Geoecology

by

Nishanta Rajakaruna, Robert S. Boyd

• LAST REVIEWED: 28 October 2014
• LAST MODIFIED: 28 October 2014
• DOI: 10.1093/obo/9780199830060-0125

Introduction

Geology plays a fundamental role in shaping the biotic world around us. Geologic history (plate tectonics and orogenic or mountain-building activity), landforms (geomorphology), and lithology (parent material and substrate) influence ecological and evolutionary processes and contribute to both macro- and micro-scale patterns of biogeography. Geoecology is an interdisciplinary and multidisciplinary science that integrates the geosciences with the life sciences, focusing on the myriad influences of geological processes on historical and contemporary patterns of biogeography, including the causes and consequences of geoedaphics on biota at all temporal and spatial scales. At the same time, geoecology examines the role biota play in a range of geoedaphic processes, including in weathering and pedogenesis, thereby altering the chemical and physical composition of the Earth’s surface and its patterns of biodiversity. Geobiology (geobotany and geozoology), biogeography, and biogeochemistry are important subfields within geoecology. Much of earth’s biotic heterogeneity is a direct result of ecological heterogeneity stemming from geoedaphic influences. Early naturalists often associated the occurrence of certain plant species with particular geologies, leading to biogeochemical prospecting for highly sought after minerals and metals. Recent advances in biogeochemical studies have led to phytomining, the use of plants to extract metals such as nickel and gold from metal-enriched soils. Plant evolutionary ecology also has its roots in geoecology, with pioneering experimental studies highlighting the influence of landforms and geoedaphics on plant fitness and the evolutionary process, leading to the development of the concept of ecotypes—genetically distinct populations that are locally adapted to specific habitats characterized by distinct environmental conditions. Chemically imbalanced (i.e., nutrient poor or metal rich) geologic materials, such as serpentinites, contribute greatly to biodiversity, with high levels of plant endemism in regions overlying such geologies. Study of these endemic plants has contributed to ecological and evolutionary theory as well as basic and applied aspects of conservation and restoration sciences. Recent advances in geographic information science (GIS) and remote sensing, including light detection and ranging (LiDAR) and satellite imagery, combined with advanced computational techniques, have also provided means to closely monitor changes in patterns and processes of biota spread across geologic, topographic, and related ecological gradients. Such advances have led to effective conservation planning and better management of threats to biota resulting from stressors associated with climate change.

General Overviews

Geoecology is the study of the multifaceted relationships that exist between substrate and biota. Parent materials, climate, topography, and time determine the kind of substrate that becomes available for colonization by biota, and their habitation further influences the nature of the substrate upon which plants grow and animals and microbes dwell. Humans have long observed the special associations between organisms and their substrate, and such knowledge has served as the foundation of biogeoprospecting, the use of organisms as indicators of minerals and chemical elements found within geologic material. Martin and Coughtrey 1982 and Brooks 1983 (cited under Flora) are excellent resources for the early literature on this topic, particularly in Europe. Huggett 1995 is an authoritative treatment of geoecology, providing an extensive discussion on the roles that climate, geology, soils, altitude, topography, insularity, and disturbance play in generating and maintaining patterns of biotic diversity. Knoll, et al. 2012 is also a good resource for a solid foundation on geobiological topics, including the role of nutrient cycles in biological processes and biota as geobiological agents, in addition to information on geobiological weathering, paleogeobiology, and technological advances in geobiological research. Much of the research on geoecology has focused on microbe- and plant-substrate relations. Konhauser 2006 is an excellent introduction to the geoecology of microbes, while Kruckeberg 2002 is a comprehensive treatment on the roles that geology, topography, and geologic history play in shaping plant communities. Some plant-geology interactions have received more attention than others, particularly on serpentinites, due to their hosting unique communities containing a high proportion of endemic and rare species. Roberts and Proctor 1992 is an early but comprehensive treatment on the ecology of serpentinite-associated plants. Alexander, et al. 2007 explores the substrate-biota relationships for the serpentinites of western North America, a region that has been the focus of geoecological investigations since the mid-1900s. For recent treatments on the ecology and evolution of serpentinite habitats, see Brady, et al. 2005 and Harrison and Rajakaruna 2011 (both cited under Evolutionary Aspects). Unlike studies for plants and microbes, studies examining the role of lithology on animals are relatively scarce (but see citations under Fauna). Animal studies typically focus on how geologic history and landforms (and associated climatic conditions) influence animal ecology and evolution. Barrett and Peles 1999 is a good introductory resource for such information, including how landscape patterns and processes impact small mammals and how they, in turn, influence landscape structure and composition.

• Alexander, Earl B., Robert G. Coleman, Todd Keeler-Wolf, and Susan P. Harrison. 2007. Serpentine geoecology of western North America: Geology, soils and vegetation. New York: Oxford Univ. Press.

  This book explores the ecology of serpentinite rock outcrops in western North America, focusing on soils and plants but including information on other organisms, including animals, fungi, and other microorganisms where feasible.

• Barrett, Gary W., and John D. Peles, eds. 1999. Landscape ecology of small mammals. New York: Springer.

  DOI: 10.1007/978-0-387-21622-5

  The fifteen chapters discuss case studies, providing new insights into how landscape patterns and processes impact small mammals and how small mammals, in turn, influence landscape structure and composition.

• Huggett, Richard J. 1995. Geoecology: An evolutionary approach. New York: Routledge.

  DOI: 10.4324/9780203307373

  The nine chapters introduce the reader to the structure and function of geoecosystems, their components, and their environment. The roles that climate, soils, geology, altitude, topography, insularity, and disturbance play in shaping biotic communities are a central focus of this book.

• Knoll, Andrew H., Donald E. Canfield, and Kurt O. Konhauser, eds. 2012. Fundamentals of geobiology. Oxford: Wiley-Blackwell.

  DOI: 10.1002/9781118280874

  The book is a thorough introduction to the use of molecular tools and stable isotopes in geobiological research, and to geobiology and associated topics such as the role of carbon, nitrogen, and other nutrient cycles in biological processes; geochemical origins of life; paleogeobiology; microbes; plants; animals; and humans as geobiological agents.

• Konhauser, Kurt O. 2006. Introduction to geomicrobiology. Malden, MA: Blackwell Science.

  The seven chapters provide a comprehensive review of the role microbes play in shaping Earth’s physical environments. Topics include biomineralization, microbial weathering, microbial role in contaminant mobility, bioremediation and biorecovery, the function of microorganisms in mineral dissolution and oxidation, and Earth’s early microbial life, among others.

• Kruckeberg, Arthur R. 2002. Geology and plant life: The effects of landforms and rock types on plants. Seattle: Univ. of Washington Press.

  The book explores the roles landforms, lithology, and geologic histories play in generating and maintaining plant diversity. It reviews the rich history of geobotanical studies; discusses geoedaphic influences on plant life, including in ecological and evolutionary processes; and provides an overview of human influences on the geology-plant interphase.

• Martin, Michael H., and Peter J. Coughtrey. 1982. Biological monitoring of heavy metal pollution: Land and air. Dordrecht, The Netherlands: Springer.

  DOI: 10.1007/978-94-009-7352-7

  Although published in the 1980s, the eight chapters provide an excellent overview of the historic and current uses of plants and animals to detect heavy metals in both natural and anthropogenic settings. The primary focus is on the use of plants as effective monitors of heavy metals in rocks, soils, and air.

• Roberts, Bruce A., and John Proctor, eds. 1992. The ecology of areas with serpentinized rocks: A world view. Geobotany 17. Dordrecht, The Netherlands: Kluwer Academic.

  DOI: 10.1007/978-94-011-3722-5

  After a brief geological review, thirteen contributed chapters cover serpentinite ecology in areas within North America, Europe, Africa, Australia, and Asia. Coverage reflects the limited state of knowledge at the time, but the book is a good entry point into the pre-1990s serpentinite ecology literature.