Ecology Eco-Evolutionary Dynamics
by
Thomas W. Schoener
  • LAST REVIEWED: 06 May 2016
  • LAST MODIFIED: 29 October 2013
  • DOI: 10.1093/obo/9780199830060-0030

Introduction

The effect of ecological change on evolution has been a standard scientific theme for many years, but the reverse—how evolutionary dynamics affect ecological traits such as population growth rate—has only recently begun to take hold with the increasing realization that evolution can occur over ecological time scales. This newly highlighted causal direction and the feedback loop that is then implied—eco-evolutionary dynamics—has invigorated both ecologists and evolutionists and is contributing toward blurring the distinction between them. The logic of the eco-evolutionary-dynamics movement and the resulting research program is as follows. First, many studies have shown that ecological change affects evolution; indeed, natural selection is where ecology and evolution meet, and observations of this process are observations of “evolution in action.” Second, evolution can be fast, since by definition observations of evolution in action are of very fast evolution. Third, the reverse is also possible: evolutionary dynamics can affect ecology—because evolution can be so fast, ecological time and evolutionary time can be commensurate. Indeed, natural selection and population dynamics are both affected by births and deaths of individuals so are tightly related. Fourth, the view of evolution as ponderous and frequently unidirectional is now replaced with a new view: episodes of one-way directional evolutionary selection are interspersed with episodes of stasis or even episodes of selection in the other direction, giving a dynamic interplay between evolution and ecology over real time—the eco-evolutionary feedback. Fifth, there are few empirical examples, however, of evolutionary dynamics affecting ecological dynamics. Those that do exist are either laboratory experiments with small, often even micro-organisms, or field observations of long-term processes. In particular, almost no field-experimental demonstrations of eco-evolutionary dynamics have been successfully carried out so far, yet only they can settle the question of whether the evolution-to-ecology pathway is frequent and strong enough to be important in nature. A current top research priority is performing multigenerational field experiments on eco-evolutionary dynamics. I thank Jonathan Losos and David Reznick for comments on aspects of this article, and the US National Science Foundation for support.

General Overview

“Eco-evolutionary dynamics” in this article refers to the interplay between ecological and evolutionary dynamics in real time, that is, relatively instantaneously. As so named (in 2007; see Development of the Modern Field), eco-evolutionary dynamics is such a new field of science that only one general overview exists, that of Schoener 2011, although there are several historical antecedents (see Early Papers). This paper grew out of a presentation at the University of Chicago’s 2009 symposium celebrating the 150th anniversary of the publication of Darwin’s On the Origin of Species. The solicited presentation was “Population Dynamics,” but that being a rather dry topic and not particularly evolutionary, Schoener decided to try to assemble the recent research efforts aimed at showing that evolutionary dynamics can affect ecological dynamics in real time. The resulting presentation was entitled “The Newest Synthesis: Evolution + Ecology = EvoEco,” but Science, which published Schoener 2011, would not allow abbreviations or equations in titles, so the title had to be modified to what is given just below.

  • Schoener, T. W. 2011. The newest synthesis: understanding the interplay of evolutionary and ecological dynamics. Science 331.6016: 426–429.

    DOI: 10.1126/science.1193954Save Citation »Export Citation »E-mail Citation »

    A review that grew out of a presentation at the University of Chicago’s Darwin symposium, and which attempted to synthesize much of the content of the eco-evolutionary-dynamics field as it existed at the end of 2010.

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    History

    The modern field of eco-evolutionary dynamics as I am designating it began very recently, at approximately the midpoint of the last decade. As described in the first section, a number of fairly independent research efforts quickly merged to shape the currently burgeoning eco-evolutionary movement. Several earlier papers, described in the second section, contained some or even many of the basic ideas but did not lead to the explosion of research on this topic that we presently see, perhaps because of their lack of simultaneity or because research on evolution was only beginning to reap the advantages of modern molecular methodology.

    Development of the Modern Field

    Several apparently fairly independent pathways led to the formation of the modern field of eco-evolutionary dynamics. Schoener’s presentation at the 2009 Chicago Darwin symposium, which led to the review, Schoener 2011, discussed in General Overview, was invited over two years before the actual presentation; indeed 40 percent of the papers cited therein were published during or beyond 2007, thus in approximately the previous two years! A second pathway led to the first use of the term “eco-evolutionary dynamics”: a 2007 symposium sponsored by the journal Functional Ecology entitled “Evolution on Ecological Time Scales.” The two articles having “eco-evolutionary dynamics” in the title are Kinnison and Hairston 2007 and Fussmann, et al. 2007 (see Fussmann Criteria); Nelson Hairston (personal communication) said that it was actually Kinnison who was responsible for this first modern usage of the term. A similar term, “ecogenetic feedback,” was simultaneously published in Kokko and Lόpez-Sepulcre 2007 in Ecology Letters, but that term, as well as Schoener’s “EvoEco,” have fallen by the wayside. Certain mathematical treatments assessing the simultaneous (and possibly comparable) impacts of ecology versus evolution preceded the Functional Ecology symposium and were cited in some of its papers. One was Hairston, et al. 2005, in which a statistical method was presented that partitioned the relative contributions of ecology and evolution to some property such as population growth as it varied over time (see Geber Methods). The other treatment, begun in the paper Coulson, et al. 2006, gave a matrix-based mathematical framework for linking evolutionary and ecological quantities that eventually led to their Integral Projection Model (IPM) approach. Yet another pathway was embodied in Strauss, et al. 2007, a “perspective” in Ecology Letters. Although in the same department, Strauss and Schoener independently became convinced that rapid evolution was likely to influence the results of their field-ecological experiments, on plants and lizards, respectively. The paper focused on how evolutionary adaptation might change ecological effect magnitudes over time. Both Strauss, et al. 2007 and Hairston, et al. 2005 were in turn influenced by laboratory experiments on a system of predators (rotifers) and prey (algae) in Yoshida, et al. 2003. A final important benchmark in this very recent history was the Royal Society’s 2009 symposium called in fact “Eco-Evolutionary Dynamics” (Pelletier, et al. 2009). This symposium contained a large number of influential papers, including some discussed in Field Experiments on Population and Guild-Composition Effects on Community and Ecosystem Properties and Recent Laboratory Experiments on Eco-Evolutionary Dynamics.

    • Coulson, T., T. G. Benton, P. Lundberg, S. R. X. Dall, and B. E. Kendall. 2006. Putting evolutionary biology back in the ecological theatre: a demographic framework mapping genes to communities. Evolutionary Ecology Research 8:1155–1171.

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      Hugely encompassing, ambitious mathematical framework that began the series of models and applications by the Coulson research group, whose most recent effort is an application of integral projection models to wolves. In the author’s words, the framework links “genotypic, phenotypic, individual, population and community levels of organization (p. 1155).”

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      • Hairston, N. G., Jr., S. P. Ellner, M. A. Geber, T. Yoshida, and J. Fox. 2005. Rapid evolution and the convergence of ecological and evolutionary time. Ecology Letters 8.10: 1114–1127.

        DOI: 10.1111/j.1461-0248.2005.00812.xSave Citation »Export Citation »E-mail Citation »

        The first of two major papers (see Geber Methods) allowing statistical decomposition of trait data (such as population growth through time) into evolutionary and ecological contributions.

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        • Kinnison, M. T., and N. G. Hairston Jr. 2007. Eco-evolutionary conservation biology: contemporary evolution and the dynamics of persistence. Functional Ecology 21:444–454.

          DOI: 10.1111/j.1365-2435.2007.01278.xSave Citation »Export Citation »E-mail Citation »

          A paper that focuses on the implications of ongoing evolution for the persistence of populations under the circumstances: populations in place, colonizing populations, and populations subjected to gene flow and in metapopulations. The paper may have begun the modern usage of the term “eco-evolutionary dynamics.”

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          • Kokko, H., and A. Lόpez-Sepulcre. 2007. The ecogenetic link between demography and evolution: can we bridge the gap between theory and data? Ecology Letters 10.9: 773–782.

            DOI: 10.1111/j.1461-0248.2007.01086.xSave Citation »Export Citation »E-mail Citation »

            One of the clearest and most influential statements of the concept of feedback between evolution and ecology.

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            • Pelletier, F., D. Garant, and A. P. Hendry. 2009. Introduction: Eco-Evolutionary dynamics. Philosophical Transactions of the Royal Society B: Biological Sciences 364.1523: 1483–1489.

              DOI: 10.1098/rstb.2009.0027Save Citation »Export Citation »E-mail Citation »

              The introductory paper to a milestone symposium on eco-evolutionary dynamics, with many key papers.

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              • Strauss, S. Y., J. A. Lau, T. W. Schoener, and P. Tiffin. 2007. Evolution in ecological field experiments: implications for effect size. Ecology Letters 11:199–207.

                DOI: 10.1111/j.1461-0248.2007.01128.xSave Citation »Export Citation »E-mail Citation »

                Vanguard perspective arguing that under many circumstances, ongoing, rapid evolution should influence the results of ecological field experiments, a possibility almost completely ignored by ecologists at the time of its publication.

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                • Yoshida, T., N. G. Hairston Jr., and S. P. Ellner. 2003. Rapid evolution drives ecological dynamics in a predator-prey system. Nature 424:303–306.

                  DOI: 10.1038/nature01767Save Citation »Export Citation »E-mail Citation »

                  Pioneering laboratory study of eco-evolutionary dynamics showing how the puzzling almost-perfectly-out-of-phase oscillations of predators (rotifers) and prey (algae) could only be explained by a model that incorporated evolution of the prey driven by the predator.

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                  Early Papers

                  Beginning in 1961, Pimentel 1961 and colleagues published a series of papers which proposed the genetic feed-back mechanism, whose ultimate goal was to explain how evolutionary change can modify oscillations in population numbers—in this way presaging Yoshida, et al. 2003 (cited under Development of the Modern Field) by almost fifty years. Although the theory was mostly verbal with very sketchy mathematics, some of this group’s experiments were impressive indeed. In a predator-prey system with parasitoid wasps (predators) and houseflies (prey), evolution toward increased resistance in the prey and reduced virulence in the predator gave relatively stable population dynamics. In controls preventing evolution of prey resistance by continual replacement with unexposed prey stocks, unstable fluctuations occurred. An apparently independent line of reasoning was developed in Chitty 1960 (summary in Stenseth and Imms 1993) to explain rodent cycles: selection for spacing/aggression/dispersal rises and falls with changes in population density; this alternation was argued to produce a cycle. As discussed in Stenseth and Imms 1993, modeling has shown that if anything the opposite should happen, and indeed the latter would be consistent with the Pimentel results. The first general theoretical coalescence of such ideas was the mathematical treatment of Levin and Udovic 1977, in which both population-size and genotype-frequency variables were considered in the same framework. This paper concluded that coevolutionary interaction between two species can either stabilize or destabilize a purely ecological interaction. The synthetic chapter Antonovics 1992 developed the Levins-Udovic theme further and explicitly related it to ongoing work and modeling of a plant host/parasite system; the paper is in some ways a heralding of the eco-evolutionary-dynamical movement, although the latter took another two or three decades to really get going. Another theoretical paper contains the model of character displacement—the coevolution of trait differences such as those in feeding appendages—formulated in Taper and Case 1985. Most such models do not contain explicit dynamics of the food resource, but theirs does, thereby qualifying as an early model of eco-evolutionary dynamics. Finally, the prescient summary in Thompson 1998 of one of the first conferences under the auspices of the National Center for Ecological Analysis and Synthesis (NCEAS) pointed the way toward the modern general goal of eco-evolutionary research, which is to determine “whether the persistence of interactions and the stability of communities truly rely upon ongoing rapid evolution . . . or whether such rapid evolution is ecologically trivial” (p. 329).

                  • Antonovics, J. 1992. Toward community genetics. In Plant Resistance to Herbivores and Pathogens. Edited by R. S. Fritz and E. L. Simms, 426–440. Chicago: Univ. of Chicago Press.

                    DOI: 10.7208/chicago/9780226924854.001.0001Save Citation »Export Citation »E-mail Citation »

                    Final chapter in a volume on how plants combat herbivory and parasitism. The chapter specifically discusses the author’s research on the perennial weed Silene alba and its pathogen the smut Ustilago violacea, but it is more generally valuable for discussion of the two-way interaction between evolutionary and ecological variables.

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                    • Chitty, D. 1960. Population processes in the vole and the relevance to general theory. Canadian Journal of Zoology 38:99–113.

                      DOI: 10.1139/z60-011Save Citation »Export Citation »E-mail Citation »

                      Probably the first Chitty paper to formulate his hypothesis on population fluctuations: the alternation as a function of population density of selection for or against spacing/aggression drives the cycle of certain rodents.

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                      • Levin, S. A., and J. D. Udovic. 1977. A mathematical model of coevolving populations. American Naturalist 111:657–675.

                        DOI: 10.1086/283198Save Citation »Export Citation »E-mail Citation »

                        A general mathematical treatment that provides a framework (see especially their Fig. 1) for relating ecological (population sizes) and evolutionary (gene frequencies) in all possible intraspecific and interspecific ways for two species. Both discrete and continuous approaches are used, and stability conditions are discussed.

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                        • Pimentel, D. 1961. Animal population regulation by the genetic feed-back mechanism. American Naturalist 95:65–79.

                          DOI: 10.1086/282160Save Citation »Export Citation »E-mail Citation »

                          A classic general conceptual statement of the author’s genetic feedback mechanism, one which was later tested in laboratory experiments (see Fussmann Criteria).

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                          • Stenseth, N. C., and R. A Imms. 1993. Population dynamics of lemmings: Temporal and spatial variation—an introduction. In The Biology of Lemmings. Edited by N. C. Stenseth and R. A. Imms, 62–96. London: Academic Press.

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                            Excellent summary of the possible causes of lemming population cycles as was conceptualized in the late 1990s, with a critique of several versions of the Chitty hypothesis.

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                            • Taper, M. L., and T. J. Case. 1985. Quantitative genetic models for the coevolution of character displacement. Ecology 66:355–371.

                              DOI: 10.2307/1940385Save Citation »Export Citation »E-mail Citation »

                              Elaborate mathematical model of character displacement, allowing for evolution of both within- and between-phenotypic variance. The models correctly predict that species differences decline with number of species in a community, that within-phenotype niche width exceeds between-phenotype niche width, and that phenotypic separation exceeds niche separation. Inclusion of explicit resource dynamics makes it an early theoretical representation of eco-evolutionary dynamics.

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                              • Thompson, J. N. 1998. Rapid evolution as an ecological process. Trends in Ecology and Evolution 13.7: 329–332.

                                DOI: 10.1016/S0169-5347(98)01378-0Save Citation »Export Citation »E-mail Citation »

                                Summary of an important NCEAS conference which includes four ways in which evolution could influence ecological processes. Contains a prescient statement of the current goal of eco-evolutionary research.

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                                Rapid Evolution

                                Rapid evolution is a necessary part of the argument for eco-evolutionary dynamics, since those evolutionary processes that interact with ecological processes in real time have to be as fast as the latter. Many documentations of rapid evolution—“natural selection in action”—are now in the literature, including case studies on a variety of organisms as well as synthetic surveys of the rapidly increasing number of observations of rapid evolution, many caused by human alterations to the environment.

                                Case Studies

                                The historically most famous example of rapid evolution is industrial melanism, in which various moth species have both light and dark morphs: the latter better match tree trunks blackened from soot and the death of light-colored lichens, thereby providing better concealment from predators. We now know (Majerus 1998) that the moths don’t normally perch on tree trunks but rather on little branches, throwing a wrinkle if not a wrench into the classical story. Yet evolution indeed occurred, and its direction reversed after pollution abated. Another example (Antonovics, et al. 1971) of human-driven rapid evolution is in plants: grass growing on waste-heaps from mines have genetically based tolerance of specific toxic metals. An entirely natural example is Geospiza fortis, a Galapágos finch, which evolved larger beaks during dry years when large seeds were relatively more available; again, this evolution reversed during wet years (see Grant and Grant 1993, Grant and Grant 2002, and Grant and Grant 2008, all cited under First Geber Method). Physiological, and even behavioral, traits, can evolve rapidly: Australian black snakes evolved both a physiological resistance to and a behavioral avoidance of introduced cane toads in less than twenty-three generations (Phillips and Shine 2006). Several examples involve life histories and morphologies of fish. Heavy fishing resulted in Atlantic Cod evolving earlier maturity and smaller body size (Olsen, et al. 2004); the same was observed among guppies following experimental fish-predator introduction (Reznick, et al. 1990). Twenty-six generations after being introduced to New Zealand, locally adapted Chinook salmon had more than double the fitness of nonlocals (Kinnison, et al. 2008). Evolutionary change went to an even greater extreme in the congeneric trout Oncorhynchus mykiss, which has two forms—steelhead and rainbow—the former migratory and the latter sedentary. A rainbow population above a river-barrier waterfall evolved from a steelhead introduction in c. 1910, and fish that got back over the falls are reproductively isolated from the ancestral steelhead (Pearse, et al. 2009), thereby being a sensational case not just of rapid evolution but of rapid speciation! Indeed Christie, et al. 2012 showed in the same species that genetic adaptation to captivity can occur in a single generation: captive-born individuals have about twice the reproductive success as wild-born in captivity, and about one-third the successful return to the wild as wild-born. Finally, in many cases resistance to drugs by pathogens and insecticides by pests have arisen by rapid evolution. A notorious example is resistance of the malarial-causing plasmodium to most drugs (White 2004), a public-health situation made even worse by the rapidly evolving resistance of its mosquito vector to insecticides such as DDT.

                                • Antonovics, J., A. D. Bradshaw, and R. G. Turner. 1971. Heavy metal tolerance in plants. Advances in Ecological Research 7:1–85.

                                  DOI: 10.1016/S0065-2504(08)60202-0Save Citation »Export Citation »E-mail Citation »

                                  The classic review of how plants have evolved tolerance to potentially toxic heavy metals—copper, zinc, lead, nickel—in areas associated with human mining activities. For example, the grass Agrostis tenuis can grow on waste-heaps from mines; tolerance is metal-specific and has a genetic basis. Tolerant populations are normally surrounded by non-tolerant populations, indicating selective pressures strong enough to counter gene flow.

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                                  • Christie, M. R., M. L. Marine, R. A. French, and M. S. Blouin. 2012. Genetic adaptation to captivity can occur in a single generation. Proceedings of the National Academy of Sciences of the United States of America 109:238–242.

                                    DOI: 10.1073/pnas.1111073109Save Citation »Export Citation »E-mail Citation »

                                    An extensive hatchery venue and pedigree analysis is used to show that genetic adaptation can occur in a single generation. The research illustrates clever methodology as well as produces a surprising result, even in this time of broad acceptance of rapid evolution.

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                                    • Kinnison, M. T., M. J. Unwin, and T. F. Quinn. 2008. Eco-evolutionary vs. habitat contributions to invasion in salmon: Experimental evaluation in the wild. Molecular Ecology 17:405–414.

                                      DOI: 10.1111/j.1365-294X.2007.03495.xSave Citation »Export Citation »E-mail Citation »

                                      Clever use of experimental translocations with Chinook salmon (Oncorhynchus tshawytscha) allows the authors to compare fitness traits among locally adapted versus non-locally adapted individuals. Major changes occurred after only twenty-six generations.

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                                      • Majerus, M. E. N. 1998. Melanism: Evolution in action. Oxford: Oxford Univ. Press.

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                                        Now somewhat out-of-date, this is the classic work on industrial melanism in moths, including, among other things, photos of where and how the moth Biston betularia actually perches. Some of the classic concepts are debunked, while others survive.

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                                        • Olsen, E. M., M. Heino, G. R. Lilly, et al. 2004. Maturation trends indicative of rapid evolution preceded the collapse of northern cod. Nature 428:932–935.

                                          DOI: 10.1038/nature02430Save Citation »Export Citation »E-mail Citation »

                                          Humans nearly exterminated the Atlantic cod, and the now-recovering populations show adaptations—smaller body size and earlier maturation—caused by the heavy selection pressure from the past fishing.

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                                          • Pearse, D. E., S. A. Hayes, M. H. Bond, et al. 2009. Over the falls? Rapid evolution of ecotypic differentiation in steelhead/rainbow trout (Oncorhynchus mykiss). Journal of Heredity 100.5: 515–525.

                                            DOI: 10.1093/jhered/esp040Save Citation »Export Citation »E-mail Citation »

                                            Reproductive isolation constitutes most biologists’ definition of species formation, and this has happened in salmon in a period of less, perhaps far less, than one hundred years.

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                                            • Phillips, B. L., and R. Shine. 2006. An invasive species induces rapid adaptive change in a native predator: Cane toads and black snakes in Australia. Proceedings of the Royal Society of London B 273:1545–1550.

                                              DOI: 10.1098/rspb.2006.3479Save Citation »Export Citation »E-mail Citation »

                                              Introduced cane toads (Bufo marinus) are lethally toxic to predatory black snakes (Pseudechis porphyriacus) so selection is extreme; both resistance to the toxin, as well as avoiding the toads altogether as prey, has occurred over twenty-three generations. This story is not over—how will these two adaptive trends equilibrate?

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                                              • Reznick, D. A., H. Bryga, and J. Endler. 1990. Experimentally induced life-history evolution in a natural population. Nature 346:357–359.

                                                DOI: 10.1038/346357a0Save Citation »Export Citation »E-mail Citation »

                                                The classic experimental study of the evolution of life-history traits in response to predation, involving guppies and piscivorous fish. The procedure actually is only a predator-removal, since guppies were transplanted from a site where they co-occurred with predators to a site above a barrier waterfall that excluded guppies and predators.

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                                                • White, N. J. 2004. Antimalarial drug resistance. Journal of Clinical Investigation 113:1084–1092.

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                                                  Malaria is the most “prevalent and pernicious” parasitic disease of humans, killing 1–2 million people per year. Resistance has evolved to all classes of antimalarial drugs except the artemisinins and is responsible for a recent increase in malaria-related mortality, particularly in Africa. Use of antimalarial drug combinations prevents this evolution of resistance to some extent.

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                                                  Surveys

                                                  The number of reliable studies in which natural selection has been observed has increased markedly since Endler 1986 reviewed them in his now classic book Natural Selection in the Wild. The most recent comprehensive discussions characterizing which traits evolve and under what circumstances are in Reznick and Ghalambor 2001 and Reznick, et al. 2004: forty-seven studies demonstrating or implying rapid evolution involve a variety of traits: morphological, physiological, life-historical, phenological, and behavioral. Almost all examples are either of colonization events, in the sense of invasion of new areas, or of local changes in semi-isolated populations (metapopulations) spread over a varying environment. It would be interesting to see if these generalizations hold up today, but a more recent comprehensive review of natural selection in nature has not been performed. This will be a daunting task—Scott Carroll (personal communication) has guessed there will be an order-of-magnitude more studies available now than was the case ten years ago: here is a long paper, if not a book, to be written! While the Reznick/Ghalambor examples are all in nature rather than the laboratory, humans, by deliberate or accidental introduction or other environmental modification, have spurred many of them; indeed without recent and severe anthropogenic activities, the list of cases of rapid evolution would be much shorter. Two recent studies highlight the efficacy of humans as selective agents. Hendry, et al. 2008 show that rates of phenotypic change are smaller under natural environmental variation than in human-affected situations such as harvesting, acidification, thermal “pollution,” and chemical poisoning. Darimont, et al. 2009 divide the human effects into those due to harvesting versus the others; average phenotypic changes are 50 percent greater in the former (and over 300 percent greater than naturally induced changes). Palkovacs, et al. 2012 gives a summary of the ways humans induce changes in ecological properties of populations, communities, and ecosystems.

                                                  Direction and Magnitude of Selection

                                                  Given that evolution can be so fast (see Rapid Evolution), evolutionary and ecological time are commensurate. Indeed, natural selection and population dynamics are both affected by births and deaths of individuals (see Integral Projection Models). In fact, in the founding paper on calculating selection gradients—Lande and Arnold 1983—one of the examples was severe mortality from a winter storm in house sparrows. While tightly related, as Saccheri and Hanski 2006 points out, fitness gains made in the course of selection might not much influence the eventual equilibrium population size, for example, the carrying capacity, which is a population size under strong negative density-dependent regulation. However, these authors say that explicit demonstrations of this possibility are few, no matter how theoretically plausible it may be. The eco-evolutionary picture of the evolution that interacts with ecology is far from the “ponderous” (Kinnison and Hairston 2007) monotonic evolution of paleontology: rather, episodes of one-way directional evolutionary selection are hypothesized to be interspersed with episodes of stasis or even episodes of selection in the other direction—giving a dynamic interplay between evolution and ecology over real time. It is now the case that we have data to examine precisely this proposal. A first cut was made in Hendry and Kinnison 1999, who showed that the longer the observation period, the weaker the evolution—thus a kind of literature bias exists. A similar trend was found later in Hoekstra, et al. 2001 for studies of survival (viability) selection. But Hairston, et al. 2005 supplemented Hendry and Kinnison’s figure with finer-scale data on two studies—the Galápagos finch Geospiza fortis and a copepod—and found that short time intervals could give very low rates of evolution as well as high ones. So there is a bias, but it is mainly with the variance of the rates. A second cut was made in Siepielski, et al. 2009, whose massive review concluded “selection can frequently change direction.” Even this very definitive conclusion did not remain unchallenged for long: Morrissey and Hadfield 2012 analyzed much of the same data and concluded—on the basis that sampling error can give apparent but in fact speciously erratic trends—that “directional selection is remarkably constant over time.” And Hereford, et al. 2004 points out ways in which the magnitude of selection can be overestimated. Things are just getting started with this issue (Siepielski, personal communication), and it will be interesting to see how such a seemingly vital piece of the eco-evolutionary program is eventually resolved.

                                                  • Hairston, N. G., Jr., S. P. Ellner, M. A. Geber, T. Yoshida, and J. Fox. 2005. Rapid evolution and the convergence of ecological and evolutionary time. Ecology Letters 8:1114–1127.

                                                    DOI: 10.1111/j.1461-0248.2005.00812.xSave Citation »Export Citation »E-mail Citation »

                                                    Landmark paper that makes several kinds of major contributions to the development of eco-evolutionary dynamics (see Geber Methods). Most relevant here is the analysis of rates of evolution on several time scales as it relates to the confidence we can have in the very high selective magnitudes that are sometimes observed.

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                                                    • Hendry, A. P., and M. T. Kinnison. 1999. The pace of modern life: Measuring rates of contemporary microevolution. Evolution 53.6: 1637–1653.

                                                      DOI: 10.2307/2640428Save Citation »Export Citation »E-mail Citation »

                                                      First of a set of three papers with the same title but different subtitle; another is in the Genetica symposium on microevolution (see Surveys). This one focuses on various ways of measuring microevolutionary rate, that quantity most useful to researchers on eco-evolutionary dynamics. The Genetica symposium contains several valuable papers on microevolutionary rates.

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                                                      • Hereford, J., T. F. Hansen, and D. Houle. 2004. Comparing strengths of directional selection: How strong is strong? Evolution 58.10: 2133–2143.

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                                                        Important paper that should be read by anyone applying the Lande-Arnold method of calculating selection gradients. The paper explores the utility of two ways of standardizing Lande-Arnold, one of which (using the trait mean) is not commonly done.

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                                                        • Hoekstra, H. E., J. M. Hoekstra, D. Berrigan, et al. 2001. Strength and tempo of directional selection in the wild. Proceedings of the National Academy of the United States of America 98:9157–9160.

                                                          DOI: 10.1073/pnas.161281098Save Citation »Export Citation »E-mail Citation »

                                                          Detailed analysis of the strength of viability selection, finding that its magnitude was exponentially distributed, and that estimates over days gave greater magnitudes than estimates over months or years.

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                                                          • Kinnison, M. T., and N. G. Hairston Jr. 2007. Eco-evolutionary conservation biology: contemporary evolution and the dynamics of persistence. Functional Ecology 21.3: 444–454.

                                                            DOI: 10.1111/j.1365-2435.2007.01278.xSave Citation »Export Citation »E-mail Citation »

                                                            The authors give three reasons why “adaptive evolution appears to be downplayed as a factor in the ecological dynamics of populations” (p. 446). See Development of the Modern Field for further discussion of this paper.

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                                                            • Lande, R., and S. J. Arnold. 1983. The measurement of selection on correlated characters. Evolution 37.6: 1210–1226.

                                                              DOI: 10.2307/2408842Save Citation »Export Citation »E-mail Citation »

                                                              The classical paper on calculating selection gradients, which arise naturally and seemingly miraculously from standard population-genetics equations. Cited many, many times.

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                                                              • Morrissey, M. B., and J. D. Hadfield. 2012. Directional selection in temporally replicated studies is remarkably consistent. Evolution 66.2: 435–442.

                                                                DOI: 10.1111/j.1558-5646.2011.01444.xSave Citation »Export Citation »E-mail Citation »

                                                                Paper seriously calling into question the conclusion of Siepielski, et al. 2009 that selection can frequently change direction. Although the latter did point out the possible artifact of sampling error influencing their results, Morrissey and Hadfield 2012 believes the problem is far more serious than Siepielski, et al. 2009 imagined.

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                                                                • Saccheri, I., and I. Hanski. 2006. Natural selection and population dynamics. Trends in Ecology and Evolution 21.6: 341–347.

                                                                  DOI: 10.1016/j.tree.2006.03.018Save Citation »Export Citation »E-mail Citation »

                                                                  Another important broad treatment of how selection can influence ecological population dynamics, appearing independently and about the same time as Hairston, et al. 2005. The important point is made that strong ecological dynamics might muffle any effect of selection.

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                                                                  • Siepielski, A. M., J. D. DiBattista, and S. M. Carlson. 2009. It’s about time: the temporal dynamics of phenotypic selection in the wild. Ecology Letters 12.11: 1261–1276.

                                                                    DOI: 10.1111/j.1461-0248.2009.01381.xSave Citation »Export Citation »E-mail Citation »

                                                                    Giant review of 89 studies incorporating 5,519 estimates of selection, concluding that selection can frequently change direction over the short run. Now at odds with Morrissey and Hadfield 2012.

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                                                                    Geber Methods

                                                                    The two Geber methods are ways of calculating the relative contribution of evolution versus ecology to various traits; they thus provide one way of assessing if in fact evolution contributes significantly to ecological traits such as change in population growth rate. The first Geber method assumes all phenotypic trait change is due to evolution, that is, change in gene frequency, whereas the second Geber method allows for what is sometimes called “transmission bias,” for example, plasticity, which produces trait change that is not due to evolution.

                                                                    First Geber Method

                                                                    The simpler way of partitioning the relative effects of evolution versus ecology was introduced in Hairston, et al. 2005, in which what they later called the “Geber Method,” and which we call “Geber 1” here. (The story goes that Geber, one of the “et al.,” conceived of the basic idea in the shower—much like Archimedes!). The mathematics are straightforward. Let the response variable of the trait, for example, population growth rate, be X as a function of z and k, that is, X[z(t), k(t)] where z is a heritable evolving trait, and k is an ecological variable. Then dX/dt = (∂X/∂z)(dz/dt) + (∂X/∂k)(dk/dt), which reads that the change with time in X = the change in X due to trait evolution + the change in X due to environmental/ecological change. Each term on the right-hand side is the product of a partial derivative giving the effect of a change in z or in k on X, and a regular derivative giving how z or k change through time. The three regular derivatives can be viewed as one dependent and two independent variables in a time series, and a regression-type approach can fit the partial derivatives as coefficients. Once the coefficients are estimated, they can be plugged into the above equation along with the time series data using absolute values, and the relative contributions of the two right-hand pieces, evolution and ecology, can be estimated. Use of this method for the Grants’ (Grant and Grant 1993, Grant and Grant 2002 and personal communication; synthesis in Grant and Grant 2008) data on fluctuating population fluctuation growth of the finch Geospiza fortis gives that evolutionary contributions (via beak and body size) exceeded ecological contributions (via seed density and relative size) by a factor of 2.2. In their own copepod data, the evolutionary contribution (via life history: whether diapausing or immediately hatching eggs are produced) was one-fourth the ecological contribution (via fish predation), “less than in the finch example, but nevertheless substantial (p. 1114).” Ezard, et al. 2009 used the Geber method to partition population change for five ungulate species. They characterize the evolutionary versus ecological contribution as “statistically indistinguishable”; that model having the most support includes both factors, evolutionary and ecological, as well as the interaction between them.

                                                                    • Ezard, T. H. G., S. D. Cote, and F. Pelletier. 2009. Eco-evolutionary dynamics: Disentangling phenotypic, environmental and population fluctuations. Philosophical Transactions of the Royal Society of London B 364:1491–1498.

                                                                      DOI: 10.1098/rstb.2009.0006Save Citation »Export Citation »E-mail Citation »

                                                                      Time-series data from five ungulate species allow the Geber Method to assess the relative importance of phenotypic (mainly measures of body size) versus ecological (mainly climatic and vegetation) factors. The two emerge in a dead heat.

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                                                                      • Grant, B. R., and P. R. Grant. 1993. Evolution of Darwin’s finches caused by a rare climatic event. Proceedings of the Royal Society of London B 251.1331: 111–117.

                                                                        DOI: 10.1098/rspb.1993.0016Save Citation »Export Citation »E-mail Citation »

                                                                        Study of how a major El Nifio event affected the evolution of some Darwin’s finches on a Galápagos island. Data from this study were used in the analysis of Hairston, et al. 2005 to estimate the relative ecological versus evolutionary contributions to the total rate of change (per year) in population growth rate.

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                                                                        • Grant, P. R., and B. R. Grant. 2002. Unpredictable evolution in a 30-year study of Darwin’s finches. Science 296.5568: 717–711.

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                                                                          Study of how variable natural selection over a thirty-year period resulted in unpredictable phenotypic states for two Darwin’s finch species. Data from this study were used in the analysis of Hairston, et al. 2005 to estimate the relative ecological versus evolutionary contributions to the total rate of change (per year) in population growth rate.

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                                                                          • Grant, P., and R. Grant. 2008. How and Why Species Multiply: The Radiation of Darwin’s Finches. Princeton, NJ: Princeton Univ. Press.

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                                                                            The most recent synthesis of work by the Grants and colleagues, in which the classic work on Geospiza fortis is discussed and documented. Although of very wide scope, this book is the place to begin for comprehending any aspect of the research on Darwin’s finches, one of the longest-going field studies still in existence.

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                                                                            • Hairston, N. G., Jr., S. P. Ellner, M. A. Geber, T. Yoshida, and J. Fox. 2005. Rapid evolution and the convergence of ecological and evolutionary time. Ecology Letters 8.10: 1114–1127.

                                                                              DOI: 10.1111/j.1461-0248.2005.00812.xSave Citation »Export Citation »E-mail Citation »

                                                                              The classic paper that first introduces the Geber Method (Geber 1) for estimating the relative contributions of evolution versus ecology to traits such as change in population growth rate. The contribution of evolution is large, about the same as ecology.

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                                                                              Second Geber Method

                                                                              Ezard, et al. 2009 pointed out the possible flaw that the method discussed in First Geber Method assumes all trait change is due to evolution—but what about plasticity or changes in population structure that affect average phenotype? (The cases in Hairston, et al. 2005 have high heritability so this issue is not thought to be major for them [Ellner, et al. 2011].) Inspired in Ozgul, et al. 2009 use of the Price Equation to decompose trait change over time, Ellner, et al. 2011 rectified the possible incompleteness of their previous approach in Geber 2. There are now three terms on the right-hand side, the two in the equation above plus the change in X due to trait change not resulting from change in gene frequency but resulting from “transmission bias” such as plasticity. Incorporation of this third term might seem at first glance to disfavor the relative importance of evolution since it is part of the ecological contribution, but inter alia because of the way the absolute values are used to get the relative contributions, using Geber 2 can both help or hurt evolution depending on the particularities. Ellner, et al. 2011 give instances of both in their worked examples, and their analysis of fourteen community and ecosystem traits from Bassar, et al. 2010 mesocosm experiments show exactly half more impacted by guppy evolution and half more by guppy density—exactly equal contributions of evolution and ecology. However, selection had only a minor effect in Ozgul, et al. 2009 application to weight change over time in St. Kilda sheep.

                                                                              • Bassar, R. D., M. C. Marshall, A. Lόpez-Sepulcre, et al. 2010. Local adaptation in Trinidadian guppies alters ecosystem processes. Proceedings of the National Academy of Sciences of the United States of America 107.8: 3616–3621.

                                                                                DOI: 10.1073/pnas.0908023107Save Citation »Export Citation »E-mail Citation »

                                                                                A replicated, common garden mesocosm experiment on guppies (Poecilia reticulata), showing that differences between guppy phenotypes produce differences in community and ecosystem traits. Such phenotypic effects are further modified by effects of guppy density. Data were analyzed in Ellner, et al. 2011 to illustrate application of their Geber 2 method.

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                                                                                • Ellner, S. P., M. A. Geber, and N. G. Hairston. 2011. Does rapid evolution matter? Measuring the rate of contemporary evolution and its impacts on ecological dynamics. Ecology Letters 14.6: 603–614.

                                                                                  DOI: 10.1111/j.1461-0248.2011.01616.xSave Citation »Export Citation »E-mail Citation »

                                                                                  Methodologically a follow-up to Hairston, et al. 2005, presenting Geber 2. This method expands the calculation to include a term for non-heritable trait change, in particular plasticity. Geber 2 uses the Price Equation in its derivation. Many examples are analyzed, and the contribution of evolution is still quite large overall.

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                                                                                  • Ezard, T. H. G., S. D. Cote, and F. Pelletier. 2009. Eco-evolutionary dynamics: Disentangling phenotypic, environmental and population fluctuations. Philosophical Transactions of the Royal Society of London B 364:1491–1498.

                                                                                    DOI: 10.1098/rstb.2009.0006Save Citation »Export Citation »E-mail Citation »

                                                                                    Application of the first Geber method for assessing the relative importance of phenotypic versus ecological factors. The authors acknowledge that some of the phenotypic trait change may not be due to evolution, that is, to change in gene frequencies.

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                                                                                    • Hairston, N. G., Jr., S. P. Ellner, M. A. Geber, T. Yoshida, and J. Fox. 2005. Rapid evolution and the convergence of ecological and evolutionary time. Ecology Letters 8.10: 1114–1127.

                                                                                      DOI: 10.1111/j.1461-0248.2005.00812.xSave Citation »Export Citation »E-mail Citation »

                                                                                      This paper deals with the first Geber method, which does not take into account phenotypic trait variation not due to evolution, for example, that due to plasticity. The main cases analyzed here, however, are of organisms (finches, copepods) whose traits considered have high heritability.

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                                                                                      • Ozgul, A., S. Tuljapurkar, T. G. Benton, J. M. Pemberton, T. H. Clutton-Brock, and T. Coulson. 2009. The dynamics of phenotypic change and the shrinking sheep of St. Kilda. Science 325:464–467.

                                                                                        DOI: 10.1126/science.1173668Save Citation »Export Citation »E-mail Citation »

                                                                                        Apparently the first paper to use the Price Equation to decompose trait variation over time into evolutionary and ecological components.

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                                                                                        Other Theoretical Approaches

                                                                                        Two kinds of mathematical models have now received enough attention to be characterized as major theoretical approaches to the study of eco-evolutionary dynamics. The first, integral projection models, begun in the middle of the last decade (see Development of the Modern Field), has now more than a half-dozen papers with new ones appearing annually. The second, simultaneous differential-equation models, has a longer history, dating back as far as Levin and Udovic 1977 (cited under Early Papers)—one has the feeling that this sort of model will soon proliferate greatly, given the great empirical interest in eco-evolutionary dynamics.

                                                                                        Integral Projection Models

                                                                                        Coulson and colleagues published a series of papers in which they use integral projection models (IPMs) to simulate eco-evolutionary responses to environmental change, culminating (so far) in Coulson, et al. 2011. As Schreiber 2011 explains it, IPMs describe dynamics of populations having traits that vary continuously as well as discrete traits. Previous IPMs track how numbers of individuals with various body sizes vary over time due to births, deaths, and individual growth. In analyzing data on Yellowstone wolves, Coulson, et al. 2011 adds genetics to these ecological quantities, focusing on the K locus which determines coat color. The statistical relationships between body size and births, deaths and growth are genotype specific, and the IPM includes inheritance. This mathematical framework generates eco-evolutionary change, but the details are dauntingly complex. Thus if an environmental change increases offspring body size, gray individuals become more common, variation in body size decreases, and fertility selection increases. If on the other hand environmental change increases adult growth rates, each of these predictions is reversed. Another result is that changes in the mean environment will have greater effect on population parameters than changes in the variance. More detailed descriptions of the expanded IPM methodology are Coulson, et al. 2010 and Coulson 2012. A second application of IPMs is Ozgul, et al. 2010, an analysis of yellow-bellied-marmot data collected over thirty-three years. The approach here does not incorporate genetics, but it allows the authors to understand complex dynamical relationships between phenology (emergence from hibernation), morphology (body mass), and population growth. Most recently, Smallegange and Coulson 2013 review again the IMP approach and emphasize the simultaneity in interaction between evolution and ecology that these models capture.

                                                                                        • Coulson, T., S. Tuljapurkar, and D. Z. Childs. 2010. Using evolutionary demography to link life history theory, quantitative genetics and population ecology. Journal of Animal Ecology 79.6: 1226–1240.

                                                                                          DOI: 10.1111/j.1365-2656.2010.01734.xSave Citation »Export Citation »E-mail Citation »

                                                                                          Detailed discussion of models that describe age-specific relationships between some character (such as body mass) and survival, fertility, ontogeny of the character, and distribution of reproductive allocation.

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                                                                                          • Coulson, T. 2012. Integral projections models, their construction and use in posing hypotheses in ecology. Oikos 121.9: 1337–1350.

                                                                                            DOI: 10.1111/j.1600-0706.2012.00035.xSave Citation »Export Citation »E-mail Citation »

                                                                                            Solo piece by Tim Coulson following the talk he gave upon receiving the Per Brinck Award from the journal Oikos. It suggests using the IPM models to understand eco-evolutionary dynamics, and stresses that many workers, sometimes unknowingly, have data suitable to plug into such models.

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                                                                                            • Coulson, T., D. R. MacNulty, D. R. Stahler, B. vonHoldt, R. K. Wayne, and D. W. Smith. 2011. Modeling effects of environmental change on wolf population dynamics, trait evolution, and life history. Science 334.6060: 1275–1278.

                                                                                              DOI: 10.1126/science.1209441Save Citation »Export Citation »E-mail Citation »

                                                                                              Probably the most impressive of the IPM contributions, in which population vital rates, individual growth, and coat-color genetics intertwine to yield predictions about the effects of environmental perturbations on quantities such as frequency of coat color, strength of selection on fertility, and variance of body-size distributions. The complexity of the simulations is so great that understanding the mechanisms leading to particular results can be elusive.

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                                                                                              • Ozgul, A., D. Z. Childs, M. K. Oli, et al. 2010. Coupled dynamics of body mass and population growth in response to environmental change. Nature 466:482–485.

                                                                                                DOI: 10.1038/nature09210Save Citation »Export Citation »E-mail Citation »

                                                                                                Body mass and emergence-from-hibernation phenology are related to population dynamics. More traditional IMP approach than Coulson, et al. 2012.

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                                                                                                • Schreiber, S. J. 2011. Mathematical dances with wolves. Science 334.6060: 1214–1215.

                                                                                                  DOI: 10.1126/science.1214845Save Citation »Export Citation »E-mail Citation »

                                                                                                  A very understandable commentary that accompanies Coulson, et al. 2012. Probably should be read before the latter.

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                                                                                                  • Smallegange I. M., and T. Coulson. 2013. Towards a general, population-level understanding of eco-evolutionary change. Trends in Ecology and Evolution 28:143–148.

                                                                                                    DOI: 10.1016/j.tree.2012.07.021Save Citation »Export Citation »E-mail Citation »

                                                                                                    The most recently advocacy by the Coulson group of understanding eco-evolutionary dynamics using IPMs. The simultaneity of the IPM approach is contrasted with a perceived sequential view of eco-evolutionary feedback of previous authors, although this seems more semantic than real (compare with papers in the next section). Closes with interesting questions about eco-evolutionary change showing we are just starting with this field.

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                                                                                                    Simultaneous Differential-Equation Models

                                                                                                    The Geber methods and IPM models are mathematical approaches that have immediate application to data from real organisms. Eco-evolutionary thinking is now beginning to engender more purely theoretical efforts. Use of simultaneous differential equations (with respect to time)—some having ecological and some evolutionary variables—is currently the method of choice, and this practice in fact follows what might be the first explicit differential-equation model of eco-evolutionary dynamics, that of Abrams and Matsuda 1997 (although see Early Papers for a pioneering general treatment that can encompass such models). In their “evolutionary model,” there are a predator-numbers and prey-numbers equation, plus an equation whose dependent variable represents a trait value under evolution. Certain conditions allow either limit cycles or chaos to result from a model that has a locally stable equilibrium without evolution (see Early Papers for a contrasting example; the review Abrams 2000 gives examples of evolution either stabilizing or destabilizing ecological interactions). Schreiber, et al. 2011 set up a predator-prey system with one predator and two prey (the “apparent competition” paradigm), plus an evolutionary variable (mean fitness of the predator). In their words “Classical apparent competition theory predicts that prey have reciprocally negative effects on each other. The addition of phenotypic trait variation in predation can marginalize these negative effects, mediate coexistence, or generate positive indirect effects between the prey species (p. 1582).” Finally, Vasseur, et al. 2011 constructed a model incorporating neighbor-dependent selection. Two differential equations represent a competitor either having or not having trait variation over time; a quantitative genetics derivation leads to the mean of that trait having being represented by a third differential equation. Trait variation biases the system toward greater coexistence: selection causes a species to be the superior competitor when rare and the inferior competitor when common. In summary so far, it seems that adding an evolutionary variable can either lead to greater or lesser stability, and we probably are going to find out much more about this theoretical behavior in the near future.

                                                                                                    • Abrams, P. A. 2000. The evolution of predator-prey interactions: theory and evidence. Annual Review Ecology and Systematics 31:79–105.

                                                                                                      DOI: 10.1146/annurev.ecolsys.31.1.79Save Citation »Export Citation »E-mail Citation »

                                                                                                      Although evolution can both stabilize and destabilize predator-prey dynamics, specific predictions vary. Evolution in a predator’s capture-related traits is most likely to be stabilizing. Prey evolution often increases the instability of a system that would cycle in the absence of evolutionary change, but prey evolution by itself is unlikely to destabilize otherwise stable systems and may stabilize some unstable systems. Empirical information needed to test the models is regretted as frequently lacking.

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                                                                                                      • Abrams, P. A., and H. Matsuda. 1997. Prey adaptation as a cause of predator-prey cycles. Evolution 51.6: 1742–1750.

                                                                                                        DOI: 10.2307/2410997Save Citation »Export Citation »E-mail Citation »

                                                                                                        Perhaps the first simultaneous-differential-equation model of eco-evolutionary dynamics (but see Taper and Case 1985, cited under Early Papers, for a discrete approach). Hairston, et al. 2005 (cited under First Geber Method) decomposed this model into evolutionary and ecological components, concluding that the “impact of prey evolution on predator per capita growth rate is 63 percent that of internal ecological dynamics.”

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                                                                                                        • Schreiber, S. J., D. Bolnick, and R. Bürger. 2011. The community effects of phenotypic and genetic variation within a predator population. Ecology 92.8: 1582–1593.

                                                                                                          DOI: 10.1890/10-2071.1Save Citation »Export Citation »E-mail Citation »

                                                                                                          A fascinating theoretical study, producing the entirely nonintuitive result that evolution in the predator can muffle or even reverse the negative effects of apparent competition (prey sharing a common predator).

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                                                                                                          • Vasseur, D. A., P. Amarasekare, V. H. W. Volker, and J. M. Levine. 2011. Eco-evolutionary dynamics enable coexistence via neighbor-dependent selection. American Naturalist 178:E96–E109.

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                                                                                                            In the authors’ words, they develop “a general framework for elucidating how and when selection will allow coexistence in natural communities.” Their assumption of “neighbor-dependent selection” is itself, however, not so general, but the result is that the evolution predilects coexistence; this and the last paper seem to show that evolutionary dynamics lead communities away from extinction.

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                                                                                                            Fussmann Criteria

                                                                                                            The Fussmann, et al. 2007 paper is a benchmark in the development of eco-evolutionary dynamics because it was the first systematic attempt to assess empirical support for its existence in the real world. In their words, “we review . . . the handful of examples that, we believe, come close to providing empirical support for eco-evolutionary community dynamics (p. 470).” Their criteria are: (1) Does the study document change of abundance of multiple populations over several generations? (2) Is there a record of genetic frequencies and of their changes over time? (3) Is the mechanistic link between ecological and evolutionary dynamics plausible? (4) Is there a control in the sense that dynamics in the absence of evolution are reported? In fact, of the eight studies found, none fulfills all criteria—all fulfill (1) and (3); five fail (2) and five fail (4). Five studies satisfy three criteria and two satisfied two criteria. Two of the studies are in the field and six in the laboratory; the latter are all experimental but neither of the field studies is. The two field studies are the one of Geospiza fortis discussed under Case Studies and the long-term observations of rabbits and Myxoma virus in Australia summarized in Fenner 1983. In the latter, rabbits were found over time to be less and less affected by the virus, and this was in part due to evolution of immunity in the rabbits. But that was not the whole story: tests with rabbits never exposed to the virus found that the virus itself had become less virulent! Pimentel 1961 (cited under Early Papers) and famous laboratory studies were included, as well as another lab study Yoshida, et al. 2003 (cited under Development of the Modern Field). Note that there are no field-experimental studies in the review Fussmann, et al. 2007 that support eco-evolutionary dynamics!

                                                                                                            • Fenner, F. 1983. The Florey lecture, 1983: Biological control, as exemplified by smallpox eradication and myxomatosis. Proceedings of the Royal Society of London B 218.1212: 259–285.

                                                                                                              DOI: 10.1098/rspb.1983.0039Save Citation »Export Citation »E-mail Citation »

                                                                                                              Contains the classic story about selection against virulence in the Myxoma virus, a phenomenon that some have viewed as a kind of group selection.

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                                                                                                              • Fussmann, G. F., M. Loreau, and P. A. Abrams. 2007. Eco-evolutionary dynamics of communities and ecosystems. Functional Ecology 21.3: 465–477.

                                                                                                                DOI: 10.1111/j.1365-2435.2007.01275.xSave Citation »Export Citation »E-mail Citation »

                                                                                                                The first literature review of eco-evolutionary dynamics, proposing a rather strict set of four criteria that would have to be satisfied in order to support fully the existence of the phenomenon; no studies were found that satisfied all four, so in a sense the review came up empty—however, substantial partial support was noted and deemed much better than nothing.

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                                                                                                                Recent Laboratory Experiments on Eco-Evolutionary Dynamics

                                                                                                                At least seven laboratory studies on eco-evolutionary dynamics have appeared since Fussmann, et al. 2007 sent in their review (see Fussmann Criteria) that would probably have been included were they published soon enough. This gives about twice as many papers in five years, and because all of the studies are laboratory experiments, gives better than twice as many for the latter (since two of Fussmann and colleagues’ eight were in the field; see Fussmann, et al. 2007, cited under Fussmann Criteria). The laboratory experiments are on short-generationed organisms—the highest organism was a mosquito (coupled with protozoans; TerHorst, et al. 2010)—and three pairs of organism were bacteria and phage (Brockhurst, et al. 2007; Bull, et al. 2006; and Kerr, et al. 2006). Two of the studies were published in 2006, thus predating the publication date of Fussmann, et al. 2007 (cited under Fussmann Criteria) (but the latter did not see these papers [Fussmann personal communication] so did not in fact disqualify them). Bull, et al. 2006 showed that bacteriophage in chemostats with continuous influx of their essential resource (bacteria) experience eco-evolutionary feedback. First, viral density was low because the viruses were poorly adapted, as little competition was present. This favored faster multiplying viruses, leading to higher population densities, but then other genotypes were selected for as competitive ability was increasingly favored. Kerr, et al. 2006 also used bacteriophages in a laboratory metapopulation set-up; restricted migration between sites resulted in evolutionary restraint in resource use as selfish individuals caused their subpopulations to become extinct. This is similar to the scenario with rabbits and Myxoma virus, in which the latter evolved reduced virulence (see Fussmann Criteria). The experiments of Brockhurst, et al. 2007 with phage and a different genus of bacteria also simulated a metapopulation system. In contrast to Kerr, et al. 2006, the study of Lennon and Martiny 2008 found that the main evolutionary mechanism in their study of bacteria and viruses was evolution of the host. Two papers in Becks, et al. 2010 and Becks, et al. 2012 (cited under Prospect) on Chlamydomonas algae and rotifers get into the genetic mechanisms of the evolutionary dynamics in depth, the first looking at genetic variance and the second at actual functional genetics. Finally, another installment in Yoshida, et al. 2007 of their ongoing set of studies on the Chlorella-alga/rotifer system appeared after publication of the Fussmann, et al. 2007 criteria (cited under Fussmann Criteria), for which their earlier paper had already qualified. (The study in Lawrence, et al. 2012 was also with microorganisms—bacteria—and while not explicitly on ongoing eco-evolutionary dynamics, was related by the authors to the latter.)

                                                                                                                • Becks, L., S. P. Ellner, L. E. Jones, and N. G. Hairston Jr. 2010. Reduction of adaptive genetic diversity radically alters eco-evolutionary community dynamics. Ecology Letters 13:989–997.

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                                                                                                                  Chemostat experiments in which heritable variation in defense ability of an algal prey (Chlamydomonas reinhardtii) caused radically different population dynamics in their rotifer predator (Brachionus calyciflorus). Mathematical models of this kind of system reproduced the empirical dynamics down to the finest detail.

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                                                                                                                  • Brockhurst, M. A., A. Buckling, V. Poullain, and M. E. Hochberg. 2007. The impact of migration from parasite-free patches on antagonistic host-parasite coevolution. Evolution 61:1238–1243.

                                                                                                                    DOI: 10.1111/j.1558-5646.2007.00087.xSave Citation »Export Citation »E-mail Citation »

                                                                                                                    Several ways in which host migration can influence host-parasite coevolution are explored using bacteriophage and Pseudomonas bacteria in a laboratory metapopulation setting. Host immigration can actually increase coevolutionary rates under certain conditions.

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                                                                                                                    • Bull, J. J., J. Millstein, J. Orcutt, and H. A. Wichman. 2006. Evolutionary feedback mediated through population density, illustrated with viruses in chemostats. American Naturalist 167:E39–E51.

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                                                                                                                      Experiments using bacteria and bacteriophage showing that selection switches between rapidly reproducing viruses to less rapidly reproducing viruses but with greater competitive ability, in turn affecting the selective environment provided by the host.

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                                                                                                                      • Kerr, B., C. Neuhauser, B. J. M. Bohannan, and A. M. Dean. 2006. Local migration promotes competitive restraint in a host-pathogen “tragedy of the commons.” Nature 442:75–78.

                                                                                                                        DOI: 10.1038/nature04864Save Citation »Export Citation »E-mail Citation »

                                                                                                                        Fascinating experiment showing that in a subdivided population with finite but limited dispersal between the subpopulation sites, less rapacious predators (phage) were selected for. Resembles the rabbit-Myxoma situation in that lower virulence is selected for, but neither that study nor the group-selection framework in which it has been couched are cited (see Fussmann Criteria).

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                                                                                                                        • Lawrence, D., F. Fiegna, V. Behrends, et al. 2012. Species interactions alter evolutionary responses to a novel environment. PLoS Biology 10.5.

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                                                                                                                          Five species of decomposer bacteria evolved traits in communities that were different than traits in monocultures, diverging in resource use and using other species’ waste products. The evolution affected an ecosystem property—productivity—as in certain studies in Field Experiments on Population and Guild-Composition Effects on Community and Ecosystem Properties.

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                                                                                                                          • Lennon, J. T., and J. B. H. Martiny. 2008. Rapid evolution buffers ecosystem impacts of viruses in a microbial food web. Ecology Letters 11:1178–1188.

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                                                                                                                            Study using autotrophic marine bacteria (Synechococcus) as a viral host and also observing other trophic types of bacteria. Viruses dramatically alter host population dynamics, in turn influencing phosphorus; heterotrophic bacteria were not much affected. Unlike the rabbit-Myxoma case, the mechanism driving these changes is the evolution of resistance in the host; viral effects diminished over time.

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                                                                                                                            • TerHorst, C. P., T. E. Miller, and D. R. Levitan. 2010. Evolution of prey in ecological time reduces the effect size of predators. Ecology 91:629–636.

                                                                                                                              DOI: 10.1890/09-1481.1Save Citation »Export Citation »E-mail Citation »

                                                                                                                              Two organisms naturally found in pitcher plants, mosquitoes and their protozoan prey, are used in laboratory microcosm experiments to determine how the effect size of predators may diminish over time as their prey evolve. This nicely illustrates a parallel expectation for field experiments in Strauss, et al. 2007 (cited under Development of the Modern Field).

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                                                                                                                              • Yoshida, T., S. P. Ellner, L. E. Jones, B. J. M. Bohannan, R. E. Lenski, and N. G. Hairston Jr. 2007. Cryptic population dynamics: Rapid evolution masks trophic interactions. PLoS Biology 5.9: e235.

                                                                                                                                DOI: 10.1371/journal.pbio.0050235Save Citation »Export Citation »E-mail Citation »

                                                                                                                                The well-studied Yoshida algal/rotifer system shows that strong links can be missed by traditional time-series analyses of abundance when contemporaneous rapid evolution in the prey or predator is present: the predator can exhibit large-amplitude cycles while prey abundance varies little. Mathematics shows such cryptic dynamics are favored by rapid prey evolution for traits defending against attack and defense cost is low.

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                                                                                                                                Effects of Genetic Structure on Ecological Properties

                                                                                                                                A variety of studies, many quite recent, document effects of genetic structure on ecological properties. While such studies do not observe ongoing eco-evolutionary dynamics directly, they provide important support of a principal assumption of the research program: that evolutionary change, defined as change in gene frequencies, affects ecological traits. Approaches can be experimental or correlative. A relatively recent example of the former is Crutsinger, et al. 2006, in which twenty-one genotypes of goldenrod were sampled to seed into plots representing a range of genotype numbers. Species numbers of both herbivorous and predatory arthropods increased with genotype number, as did a measure of productivity. A second example is Johnson and Agrawal 2005, in which fourteen genotypes of evening primrose were planted into a range of natural habitats. Genotypic differences among plants accounted for up to 41 percent of variation in arthropod diversity; arthropod evenness, richness, abundance, and biomass on individual plants were also affected. Various reviews of the effects of genetic diversity emerged a few years later than these experimental papers. Haloin and Strauss 2008 provide an extensive table of the kinds of community properties that have been shown to be affected by genetic diversity. Hughes, et al. 2008 conclude that while a large number of examples exist of genetic diversity affecting community and ecosystem properties, they are biased toward clonal plants so we don’t really know how widespread the phenomenon is. Bailey, et al. 2009 reviews plant studies and concludes that genetic variation has less of an effect the higher the level of organization, being strongest at the individual level, weakest at the ecosystem level, and intermediate at the community level. In the most recent general assessment, Hersch-Green, et al. 2011 calls for a second generation of research that “includes a mechanistic genes-to-ecosystem understanding of natural systems;” experiments are needed at every level and linkage. In some sense this undertaking is underway in the astonishing series of poplar studies summarized in Whitham, et al. 2006, ranging from functional genetics to eco-evolutionary feedback. Whitham, et al. 2006 is also important for its introduction of the term “community heritability,” defined in the broad sense as “the tendency for related individuals to support similar communities of organisms and ecosystem processes.” Their concept of course applies to ecosystems as well, and they suggest may even apply to trophic interactions. It will be interesting to see to what extent this language and its accompanying research approaches will be picked up by other workers.

                                                                                                                                • Bailey, J. K., J. A. Schweitzer, F. Ubeda, et al. 2009. From genes to ecosystems: A synthesis of the effects of plant genetic factors across levels of organization. Philosophical Transactions of the Royal Society of London B 364:1607–1616.

                                                                                                                                  DOI: 10.1098/rstb.2008.0336Save Citation »Export Citation »E-mail Citation »

                                                                                                                                  Extensive review of plant studies showing that genetic variation has less effect the higher the level of organization: it is strongest at the individual level (phytochemistry, architecture, physiology), weaker at the community level (species richness, total abundance, community composition) and weakest at the ecosystem level (carbon accumulation, productivity, soil-nutrient dynamics), but sometimes ecosystem properties can be affected quite strongly.

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                                                                                                                                  • Crutsinger, G. M., M. D. Collins, J. A. Fordyce, Z. Gompert, C. C. Nice, and N. J. Sanders. 2006. Plant genotypic diversity predicts community structure and governs an ecosystem process. Science 313:966–968.

                                                                                                                                    DOI: 10.1126/science.1128326Save Citation »Export Citation »E-mail Citation »

                                                                                                                                    Experiment in which twenty-two genotypes of a goldenrod species (Solidago altissima) were randomly sampled to give replicated plots of one, three, six or twelve genotypes. Aboveground net productivity and several measures of arthropod diversity increased as genotypic diversity increased.

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                                                                                                                                    • Haloin, J. R., and S. Y. Strauss. 2008. Interplay between ecological communities and evolution. Annals of the New York Academy of Sciences 1133:87–125.

                                                                                                                                      DOI: 10.1196/annals.1438.003Save Citation »Export Citation »E-mail Citation »

                                                                                                                                      A huge, wide-ranging review that includes but is far from limited to how genetic variation within species affects ecological properties. Curiously, this paper is hardly ever cited in the literature.

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                                                                                                                                      • Hersch-Green, E. I., N. E. Turley, and M. T. J. Johnson. 2011. Community genetics: what have we accomplished and where should we be going? Philosophical Transactions of the Royal Society B: Biological Sciences 366:1453–1460.

                                                                                                                                        DOI: 10.1098/rstb.2010.0331Save Citation »Export Citation »E-mail Citation »

                                                                                                                                        Assessment of the field of community genetics as of early 2011.

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                                                                                                                                        • Hughes, A. R., B. D. Inouye, M. T. J. Johnson, N. Underwood, and M. Vellend. 2008. Ecological consequences of genetic diversity. Ecology Letters 11.6: 609–623.

                                                                                                                                          DOI: 10.1111/j.1461-0248.2008.01179.xSave Citation »Export Citation »E-mail Citation »

                                                                                                                                          A review showing significant effects of genetic diversity on inter alia primary productivity, recovery from disturbance, interspecific competition, species richness of arthropods, and flow of energy and nutrients.

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                                                                                                                                          • Johnson, M. T. J., and A. A. Agrawal. 2005. Plant genotype and environment interact to shape a diverse arthropod community on evening primrose (Oenothera biennis). Ecology 86:874–885.

                                                                                                                                            DOI: 10.1890/04-1068Save Citation »Export Citation »E-mail Citation »

                                                                                                                                            Experiment in which plants from fourteen genotypes of Oenothera biennis were planted into five natural habitats. Arthropod diversity, evenness, abundance, and biomass were affected. Effects of particular genotypes varied across habitats. Plant genotype explained more variation in the arthropod community than did environmental variation among microhabitats, but less variation than habitat.

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                                                                                                                                            • Whitham, T. G., J. K Bailey, J. A. Schweitzer, et al. 2006. A framework for community and ecosystem genetics: from genes to ecosystems. Nature Reviews 7:510–523.

                                                                                                                                              DOI: 10.1038/nrg1877Save Citation »Export Citation »E-mail Citation »

                                                                                                                                              Summary of the hugely multidisciplinary research by Whitham and colleagues on poplars, truly from genes to ecosystems. Important new concepts such as community heritability are introduced.

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                                                                                                                                              Field Experiments on Population and Guild-Composition Effects on Community and Ecosystem Properties

                                                                                                                                              This section collects studies that comprise eco-evolutionary field experiments but do not follow evolutionary change over multiple generations. Most can be thought of as simulating points on the eco-evolutionary time course, in which the points comprise different evolutionary stages of component species. A common design is to use species and/or populations within species as experimental treatments and various community and ecosystem properties as response variables. Harmon, et al. 2009 take advantage of the well-studied Schluter stickleback system in which two species having different habitats and morphologies evolved repeatedly from a generalist species. Each species by itself and the co-occurring pair of species comprise an experimental treatment. Palkovacs, et al. 2009 is a similar experiment on the equally well-studied Reznick Trinidadian stream system: populations of two species, guppies and killifish, from three kinds of sites representing the three fish communities—species-rich high predation killifish-guppy low predation, and killifish only—are combined in four treatments to simulate invasion, evolution, and coevolution. Again with the Trinidadian system, Bassar, et al. 2010 manipulated two kinds of guppy populations with those phenotypic and life-history traits associated with different predation regimes. Bassar, et al. 2012 further investigates this system, elucidating the direct and indirect effects of the major mechanism affecting ecology—dietary differences between the two kinds of guppies. Palkovacs and Post 2009 use in a paired manipulation yet a third fish system, populations of alewife that are either migratory or landlocked; the latter have recently and rapidly diverged from the former in morphological and behavioral traits related to foraging. A final such approach is Ingram, et al. 2012 with a predator, sculpin, and a prey, again sticklebacks. Two factors—sculpin addition (control vs. one sculpin added) and stickleback population of origin (from a lake containing sculpin vs. a lake without sculpin) cross to give four treatments. These approaches are all similar in basic strategy: experimental treatments comprise representatives of populations and/or species that have had different evolutionary histories. Another approach was taken in Johnson, et al. 2009 with the evening primrose. Seeds were germinated from fourteen genotypes and grown in a greenhouse for five weeks, after which they were planted into an old field and allowed to develop. Directional selection was found for three traits, and genetically based variation of two of them affected community/ecosystem properties of arthropods.

                                                                                                                                              • Bassar, R. D., M. C. Marshall, A. Lόpez-Sepulcre, et al. 2010. Local adaptation in Trinidadian guppies alters ecosystem processes. Proceedings of the National Academy of Sciences of the United States of America 107:3616–3621.

                                                                                                                                                DOI: 10.1073/pnas.0908023107Save Citation »Export Citation »E-mail Citation »

                                                                                                                                                Guppies (Poecilia reticulata) from high and low predation environments were manipulated in an mesocosm experiment producing a number of effects on ecosystems, including biomasses of algae, invertebrates and detritus, as well as productivity, leaf decomposition rates, and nutrient flux. Differences in diet between the two kinds of guppies seemed the primary root mechanism.

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                                                                                                                                                • Bassar, R. D., R. Ferriere, A. Lόpez-Sepulcre, et al. 2012. Direct and indirect ecosystem effects of evolutionary adaptation in the Trinidadian Guppy (Poecilia reticulata). American Naturalist 180:167–185.

                                                                                                                                                  DOI: 10.1086/666611Save Citation »Export Citation »E-mail Citation »

                                                                                                                                                  Follow-up to Bassar, et al. 2010 in which the proposal that differences in diet between the two kinds of guppies is the major mechanism affecting communities and ecosystems is examined in detail. Direct and indirect effects are distinguished. Indirect effects appear minor, but a model simulation suggests the potential existence of large opposing (in direction) indirect effects that cancel.

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                                                                                                                                                  • Harmon, L. J., B. Matthews, S. Des Roches, J. M. Chase, J. B. Shurin, and D. Schluter. 2009. Evolutionary diversification in stickleback affects ecosystem functioning. Nature 458:1167–1170.

                                                                                                                                                    DOI: 10.1038/nature07974Save Citation »Export Citation »E-mail Citation »

                                                                                                                                                    Mesocosm experiment in which a benthic specialist, a limnetic specialist, an intermediate species and the pair of specialists comprise four treatments. Effects on primary production, DOM, and prey diversity differ according to treatment, but no simple trends with respect to specialization or stickleback diversity are found. Ultimate explanations for these results are expected to be complex.

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                                                                                                                                                    • Ingram, T., R. Svanback, N. J. B. Kraft, P. Kratina, L. Southcott, and D. Schluter. 2012. Intraguild predation drives evolutionary niche shift in three-spine stickleback. Evolution 66.6: 1819–1832.

                                                                                                                                                      DOI: 10.1111/j.1558-5646.2011.01545.xSave Citation »Export Citation »E-mail Citation »

                                                                                                                                                      Mesocosm experiment crossing presence/absence of a predator (the sculpin Cottus asper) and population of origin—sympatric or allopatric—of a prey (the stickleback Gasterosteus aculeatus). Sculpin presence greatly increased the mortality of allopatric but not sympatric stickleback, although the latter did have slower body growth. Sympatric stickleback included more pelagic prey in their diets, thereby depleting zooplankton.

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                                                                                                                                                      • Johnson, M. T. J., M. Vellend, and J. R. Stinchcombe. 2009. Evolution in plant populations as a driver of ecological changes in arthropod communities. Philosophical Transactions of the Royal Society B: Biological Sciences 364:1593–1605.

                                                                                                                                                        DOI: 10.1098/rstb.2008.0334Save Citation »Export Citation »E-mail Citation »

                                                                                                                                                        Field study with Oenothera biennis and arthropods (over ninety species), in which fourteen genotypes were raised in greenhouses and then transplanted to nature. The experiment showed directional selection on plant biomass, life history (annual vs biennial), and herbivore resistance. Genetically based variation in the first two affected abundance (total and by species) and diversity of arthropods.

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                                                                                                                                                        • Palkovacs, E. P., and D. M. Post. 2009. Experimental evidence that pheonotypic divergence in predators drives community divergence in prey. Ecology 90.2: 300–305.

                                                                                                                                                          DOI: 10.1890/08-1673.1Save Citation »Export Citation »E-mail Citation »

                                                                                                                                                          Mesocosm experiment comparing effects on zooplankton of anadromous versus landlocked alewife fishes (Alosa pseudoharengus); the latter have undergone recent and rapid evolution. Anadromous alewives exploit larger prey items and reduced mean body size, biomass, species richness and diversity of crustaceans, consistent with patterns observed in unmanipulated lake communities.

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                                                                                                                                                          • Palkovacs, E. P., M. C. Marshall, B. A. Lamphere, et al. 2009. Experimental evaluation of evolution and coevolution as agents of ecosystem change in Trinidadian streams. Philosophical Transactions of the Royal Society B: Biological Sciences 364:1617–1628.

                                                                                                                                                            DOI: 10.1098/rstb.2009.0016Save Citation »Export Citation »E-mail Citation »

                                                                                                                                                            Experimental mesocosms adjacent to natural streams contained one of four treatments varying presence and population-of-origin of guppies (Poecilia reticulata) and killifish (Rivulus hartii) to represent invasion, evolution, and co-evolution. Effects of evolution and coevolution for some ecosystem variables were larger than those of invasion: inter alia guppy evolution significantly affected algal variables, while killifish-guppy coevolution affected biomass of invertebrates.

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                                                                                                                                                            Prospect

                                                                                                                                                            Palkovacs, et al. 2009 says “ . . . it remains a frontier to experimentally examine the ecosystem effects of dynamically evolving (and coevolving) populations in the wild . . . one potentially critical element that can only be captured using dynamic experiments is the eco-evolutionary feedback . . . (p. 1624).” At the time of the present writing, the frontier is largely still in place. A relatively large number of laboratory experiments have been done demonstrating eco-evolutionary dynamics over multiple generations (see Recent Laboratory Experiments on Eco-Evolutionary Dynamics). Field experiments have been performed, but they are not of populations evolving over multiple generations in nature (see Field Experiments on Population and Guild-Composition Effects on Community and Ecosystem Properties). Schoener 2011 could find no example of published field experiments of eco-evolutionary dynamics that spanned multiple generations, although ongoing work on lizards by Schoener and his colleagues Jason Kolbe, Manuel Leal, Jonathan Losos and David Spiller has that ultimate objective. However, one example has since appeared, Turcotte, et al. 2011, in which the ability to evolve or not can be controlled by using two or one-clone aphids. Lizards are relatively long-lived, and even though their traits can be selected for quickly (Losos, et al. 2006), need at least a few years to turn over several generations. Arthropods, on the other hand, have quicker generational turnover, and further experiments with this taxon should be forthcoming. The same can be said for many plants, especially in the tropics, for which I know of no ongoing field experiments on eco-evolutionary dynamics. Other frontiers include integrating functional genetics into studies of eco-evolutionary dynamics as Becks, et al. 2012 have done in the laboratory with an alga and rotifer, and as Hanski 2011 is doing with butterflies; clearly, recent major advances in determining gene expression and related endeavors have jump-started this area of research. Despite all the promise, we are still not very close to resolving the question in Thompson 1998 question (cited under Early Papers): “whether the persistence of interactions and the stability of communities truly rely upon ongoing rapid evolution . . . or whether such rapid evolution is ecologically trivial” (p. 329). The present review of research in eco-evolutionary dynamics notes many positive results, but it is not always so: Lau and Lennon 2012 manipulated drought stress in a multigenerational experiment but found only weak evolutionary responses in the target plants. Indeed, it may take many generations of field experiments with both positive and negative results to resolve Thompson’s question.

                                                                                                                                                            • Becks, L., S. P. Ellner, L. E. Jones, and N. G. Hairston Jr. 2012. The functional genomics of an eco-evolutionary feedback loop: Linking gene expression, trait evolution, and community dynamics. Ecology Letters 15.5: 492–501.

                                                                                                                                                              DOI: 10.1111/j.1461-0248.2012.01763.xSave Citation »Export Citation »E-mail Citation »

                                                                                                                                                              Latest study on the Chlamydomonas/rotifer system, in which cyclical changes in predator abundance drove fluctuating selection for a heritable prey defense—cell clumping. This prey evolution markedly affected predator population growth, completing the feedback loop. Changes in gene expression were studied, with the surprising result that expression of individual genes did not change consistently between successive cycles, suggesting several transcription pathways.

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                                                                                                                                                              • Hanski, I. 2011. Eco-evolutionary spatial dynamics in the Glanville fritillary butterfly. Proceedings of the National Academy of Sciences of the United States of America 108:14397–14404.

                                                                                                                                                                DOI: 10.1073/pnas.1110020108Save Citation »Export Citation »E-mail Citation »

                                                                                                                                                                Twenty years of data on the Glanville Fritillary (Melitaea cinxia) in about four thousand meadows are reviewed with a special eye toward eco-evolutionary dynamics. Extinction and colonization in this metapopulational system affect frequency changes in a particular gene, leading to associations between genetic variation and metapopulational processes. The study is notable not only for its scope but also for the explicit linkage of functional genetics to ecology.

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                                                                                                                                                                • Lau, J. A., and J. T. Lennon. 2012. Rapid responses of soil microorganisms improve plant fitness in novel environments. Proceedings of the National Academy of Sciences of the United States of America 35:14058–14062.

                                                                                                                                                                  DOI: 10.1073/pnas.1202319109Save Citation »Export Citation »E-mail Citation »

                                                                                                                                                                  Experimental mesocosm study of Brassica rapa simulating drought stress. There was only a weak evolutionary response in this plant, but a rapid and strong response in the associated soil microbial communities. The study thus documents a major reason why evolution may not always occur.

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                                                                                                                                                                  • Losos, J. B., T. W. Schoener, R. B. Langerhans, and D. A. Spiller. 2006. Rapid temporal reversal in predator-driven natural selection. Science 314:1111.

                                                                                                                                                                    DOI: 10.1126/science.1133584Save Citation »Export Citation »E-mail Citation »

                                                                                                                                                                    Experimental introduction of a terrestrial predatory lizard on small islands caused a prey lizard to shift upward in the vegetation. During the first six months, longer-legged individuals were selected for because they could run faster on the ground, but in the second six months short-legged individuals were selected because they were more agile in the small-diametered higher vegetation that they then mostly frequented.

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                                                                                                                                                                    • Palkovacs, E. P., M. C. Marshall, B. A. Lamphere, et al. 2009. Experimental evaluation of evolution and coevolution as agents of ecosystem change in Trinidadian streams. Philosophical Transactions of the Royal Society B: Biological Sciences 364:1617–1628.

                                                                                                                                                                      DOI: 10.1098/rstb.2009.0016Save Citation »Export Citation »E-mail Citation »

                                                                                                                                                                      An elaborate experimental examination of the ecological effects of populations of two species of fishes in various combinations (see Field Experiments on Population and Guild-Composition Effects on Community and Ecosystem Properties). The need for eco-evolutionary experiments in the field is stressed.

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                                                                                                                                                                      • Schoener, T. W. 2011. The newest synthesis: understanding the interplay of evolutionary and ecological dynamics. Science 331.6016: 426–429.

                                                                                                                                                                        DOI: 10.1126/science.1193954Save Citation »Export Citation »E-mail Citation »

                                                                                                                                                                        A review of progress in eco-evolutionary dynamics by the end of 2011.

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                                                                                                                                                                        • Turcotte, M. M., D. N. Reznick, and J. D. Hare. 2011. The impact of rapid evolution on population dynamics in the wild: Experimental test of eco-evolutionary dynamics. Ecology Letters 14.11: 1084–1092.

                                                                                                                                                                          DOI: 10.1111/j.1461-0248.2011.01676.xSave Citation »Export Citation »E-mail Citation »

                                                                                                                                                                          The first multigenerational-field-experimental publication on eco-evolutionary dynamics. Clever choice of subject—the aphid Myzus persicae—allowed comparison of non-evolving (single-clone) to potentially evolving (two-clone) organisms. Evolution occurred whether or not the aphids were exposed to competitors/predators, but only in the second did they grow faster (up to 42 percent) and attain higher densities (up to 67 percent). The latter correlate with fitness, supporting the full eco-evolutionary dynamic.

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