Bryophyte Ecology

by

Heinjo During

• LAST REVIEWED: 24 July 2013
• LAST MODIFIED: 24 July 2013
• DOI: 10.1093/obo/9780199830060-0098

Introduction

Bryophytes occur in almost all terrestrial and fresh-water habitats, and their ecological role may be considerable. The 18,000+ species of the group, which consists of the three monophyletic lineages of liverworts, hornworts, and mosses, share the same complex life cycle in which the diploid sporophytes are lifelong-dependent, for at least part of their carbohydrates and nutrients, on the haploid, green gametophytes. Fertilization distances are restricted, as the spermatozoids have to swim through fluid water to the egg cells. Yet more than half of the species are unisexual, with male and female gametophytes genetically different. Possibilities to meet the other sex are enhanced by the multifarious ways of vegetative propagation and clonal growth. The water economy of bryophytes differs from that of vascular plants in that the gametophytes are poikilohydric: There is little if any control over water loss, and there are no roots. As a consequence, shoot water content may vary much, and most species can tolerate complete desiccation. Physiological activity is limited to the periods during which the shoots are moist. The length of such periods largely depends on the balance between the water storage capacity (and so, density) of the bryophyte colonies and the evaporation rate of the water, and so the roughness of the bryophyte canopy. As, within limits, a denser colony can store more water and have a smoother canopy surface and longer length of periods of physiological activity, growth rates of shoots tend to be positively correlated with density. This mode of life allows many species to grow on substrates such as bare rock that are inaccessible to vascular plants but also makes them vulnerable to pollution and climate change.

General Overviews

For many years, Smith 1982 has been the authoritative text on bryophyte ecology. Some chapters, notably those on quantitative approaches, “Bryophytes and Invertebrates” and “Sphagnum,” brought together information on areas that had hardly ever been reviewed before. Soon after, Schuster 1983–1984 provided extensive accounts of chemistry, cytology, developmental studies, genetics, physiology, phylogeny, and phytogeography of bryophytes. Dyer and Duckett 1984 reports on the rapid developments in experimental bryology, including chapters on breeding systems, uptake of mineral elements, photosynthesis, and photomorphogenesis. Bryophytes are particularly important in boreal and polar ecosystems. The wide array of studies on their structure and functioning in these ecosystems was brought together in Longton 1988, while many of the methods used may be found in Glime 1988. By then it had become abundantly clear that both at higher latitudes and elsewhere on Earth the environment was changing fast, and Bates and Farmer 1992 presents a range of studies of the responses of bryophytes to pollution and climate change. Around this time molecular methods started to provide radically new perspectives on many aspects of taxonomy, phylogeny, phylogeography, physiology, and ecology, as shown in Goffinet and Shaw 2009. As far as bryophyte ecology goes, everything now comes together in the exhaustive e-book Glime 2007.

• Bates, J. W., and A. M. Farmer, eds. 1992. Bryophytes and lichens in a changing environment. Oxford: Clarendon.

  After some introductory chapters, many aspects of responses of bryophytes and lichens to atmospheric and aquatic pollution and various other forms of environmental change are reviewed, with special attention to tropical rainforests, wetlands in general, and Sphagnum in particular.

• Dyer, A. F., and J. G. Duckett, eds. 1984. The experimental biology of bryophytes. Orlando, FL: Academic Press.

  Although experimental biology has been revolutionized by the use of molecular methods since this book appeared, its chapters provide extensive treatments of bryophyte structure and function, including much of the older literature that is often poorly accessible digitally.

• Glime, J. M. 2007. Bryophyte ecology. Houghton: Michigan Technological Univ.

  Although it is not complete as of 2012, this e-book already is the most comprehensive and up-to-date treatment of all aspects of bryophyte ecology, enhanced with a wealth of high-quality illustrations.

• Glime, J. M., ed. 1988. Methods in bryology. Nichinan, Japan: Hattori Botanical Laboratory.

  Bryophytes differ in many ways from vascular plants, and experimental methods often have to be adapted or invented in new forms. The fifty-one chapters of this book provide introductions and references for a wide variety of methods in ecology, physiology, microscopy, and anatomy.

• Goffinet, B., and A. J. Shaw, eds. 2009. Bryophyte biology. 2d ed. Cambridge, UK: Cambridge Univ. Press.

  The new edition of this textbook on bryophyte biology makes full use of the fast developments in molecular methods, as is obvious in several chapters on molecular developmental and physiology. The chapter on population and community ecology is particularly relevant for ecologists.

• Longton, R. H. 1988. The biology of polar bryophytes and lichens. Cambridge, UK: Cambridge Univ. Press.

  DOI: 10.1017/CBO9780511565212

  Bryophytes and lichens play a larger role in polar ecosystems than in almost any other part of the world. This book describes their communities, physiology, and ecology in great detail, with a lot of attention to interactions with climate and soil.

• Schuster, R. M., ed. 1983–1984. New manual of bryology. 2 vols. Nichinan, Japan: Hattori Botanical Laboratory.

  Two monumental volumes full of detailed information on bryology. The chapters on reproductive biology and phytogeography of bryophytes in Volume I and the chapter on tropical forest bryophytes in Volume II are still particularly relevant for ecologists.

• Smith, A. J. E., ed. 1982. Bryophyte ecology. London: Chapman & Hall.

  DOI: 10.1007/978-94-009-5891-3

  With in-depth treatments of water and nutrient economy of bryophytes, introductions to the ecology of bryophytes in a range of major biomes, a comprehensive treatment of palaeobryology, and a separate monograph on Sphagnum, this book even today is a rich source of data and ideas.