Island Biology

by

Christoph Kueffer, Donald Drake, José María Fernández-Palacios

• LAST REVIEWED: 19 October 2022
• LAST MODIFIED: 26 May 2016
• DOI: 10.1093/obo/9780199830060-0149

Introduction

This article focuses on the ecology, evolutionary biology, and conservation of biotas on islands surrounded by ocean. These include oceanic islands in a strict sense (i.e., volcanic islands), atolls, islands on a continental shelf, and continental fragments (i.e., islands that originated from a continental plate but are now isolated in the ocean). This article treats only the terrestrial ecology of islands, and it does not cover islands in freshwater bodies, or islandlike isolated habitats on land such as mountaintops or landscape fragments. Islands can be found in all oceans of the planet and at all latitudes and consequently in all climate zones. They are characterized by their small area and isolation from other land, although both isolation and land area vary very widely. In this article we focus mostly on islands that are fully and continuously detached from the mainland and especially treat land-bridge islands (e.g., British Isles) only marginally. Islands are often part of island groups or chains, but they can also be completely isolated. Some islands reach an elevation of several thousand meters above sea level and then share many characteristics with mountains, including elevational vegetation zonation and often strongly contrasting leeward and windward climates. There are at least twenty thousand islands more than one square kilometer in area and millions if all sizes are considered. Together they make up nearly 5.3 percent of the earth’s land area. Island biodiversity is of huge importance for global biodiversity because of its high endemism. For instance, about one quarter of vascular plant diversity is endemic to islands. Oceanic islands have long been used as model systems for research in biogeography, ecology, evolution, and conservation. Islands were crucial for the formulation of Charles Darwin’s and Alfred Russel Wallace’s evolutionary theory and later for the observation of evolution in action. The relevance of processes such as biological invasions and demographic stochasticity for conservation were first recognized through examples from islands. In biogeography, the theory of island biogeography by MacArthur and Wilson is by far the most widely cited and discussed theory. Islands are also hotspots of biodiversity loss, where conservation strategies are being tested that might save some threatened species despite the dramatic degradation of most island ecosystems.

General Overviews

Despite the great importance of islands for ecology, relatively few general scientific treatises exist. The most comprehensive up-to-date overview on islands in general is Gillespie and Clague 2009. Whittaker and Fernández-Palacios 2007, although primarily a textbook about biogeography, is an excellent starting point for many aspects of island biology. The classical work Carlquist 1974 is still an indispensable reference, and Gorman 1979 is also still a useful, short, but dense introduction to the topic. Fernández-Palacios and Morici 2004 introduces some of the key issues in Spanish. For recent developments in island biology, Kueffer, et al. 2014 can serve as an entry point. Royle 2014 is a good starting point for exploring social, political, and economic aspects of insularity and how they interact with island biology.

• Carlquist, Sherwin. 1974. Island biology. New York: Columbia Univ. Press.

  This seminal book, by an icon of island biology, proposes twenty-four hypotheses about island biotas then examines them using island floras and faunas worldwide: there is a particular focus on long-distance dispersal, functional traits, and adaptive radiation of island plants. It inspired many researchers to further investigate island species from new ecological and evolutionary perspectives and is still a source of important information on island biology and plants.

• Fernández-Palacios, José María, and Carlo Morici, eds. 2004. Ecología insular/Island Ecology. Santa Cruz de La Palma, Spain: Cabildo Insular de La Palma.

  Bilingual (Spanish and English) compilation of the fifteen contributions presented at the Island Ecology Symposium held in La Palma (Canaries) in 2002. The chapters included topics such as island biogeography, metapopulation dynamics, fragmentation, mutualistic networks, and extinction on islands, among others. This is one of the few Spanish texts in this field.

• Gillespie, Rosemary G., and David A. Clague, eds. 2009. Encyclopedia of islands. Berkeley: Univ. of California Press.

  This encyclopedia is a monumental effort that collects the existing geological and biological knowledge on all aspects of island biology, including separate entries on most important island groups and oceanic regions worldwide. With the participation of more than a hundred specialists, this indispensable reference work is a must for every island researcher and a valuable starting point for information on virtually any topic in the field of island biology.

• Gorman, Martin. 1979. Island ecology. London: Chapman & Hall.

  DOI: 10.1007/978-94-009-5800-5

  Short but dense introduction to island ecology. The text touches briefly, but consistently, upon the more important aspects of island biogeography, ecology, and evolution and is a useful introductory text for students.

• Kueffer, Christoph, Donald R. Drake, and José María Fernández-Palacios. 2014. Island biology: Looking towards the future. Biology Letters 10.10: 20140719.

  DOI: 10.1098/rsbl.2014.0719

  Discusses recent developments in island biology and highlights in particular four recent developments: emergence of (1) a global, comprehensive research community incorporating previously neglected islands and taxa; (2) macroecology and big-data analyses yielding numerous global-scale synthetic studies and detailed multi-island comparisons, (3) use of modern methodologies in genomics, phylogenetic and functional ecology, and paleoecology, and (4) tight collaboration between basic research and conservation management, using islands to test new conservation solutions for the 21st century.

• Royle, Stephen A. 2014. Islands: Nature and culture. London: Reaktion.

  A small booklet illustrated with many photographs intended for a broad audience. Introduces island studies: the interdisciplinary study of islands. The main focus is on the human geography of islands. The author discusses general features of islands or insularity and how they determine, in particular, social, political, and economic life. A previous book by the same author, Geography of Islands: Small Islands Insularity (Routledge, London, and New York, 2008) provides a more systematic but less accessible introduction to island studies.

• Whittaker, Robert J., and José María Fernández-Palacios. 2007. Island biogeography: Ecology, evolution and conservation. 2d ed. Oxford: Oxford Univ. Press.

  This textbook has achieved the status of a key reference in its field, and it is the first comprehensive overview of island biogeography since the seminal work by MacArthur and Wilson in the 1960s. It is an appropriate text for both students and researchers and is divided into four parts: island environment, ecology, evolution, and conservation, plus a glossary.