Preface to the Princeton Landmarks in Biology Edition vii Preface xi Symbols Used xiii 1. The Importance of Islands 3 2. Area and Number of Speicies 8 3. Further Explanations of the Area-Diversity Pattern 19 4. The Strategy of Colonization 68 5. Invasibility and the Variable Niche 94 6. Stepping Stones and Biotic Exchange 123 7. Evolutionary Changes Following Colonization 145 8. Prospect 181 Glossary 185 References 193 Index 201

The Theory of Island Biogeography

Conservation evaluation and phylogenetic diversity

There exists little doubt that the Earth's biodiversity is declining. The Nature Conservancy, for example, has documented that one-third of the plant and animal species in the United States are now at risk of extinction. The problem is a monumental one, and forces us to consider in depth how we expect ecosystems, which ultimately are our life-support systems, to respond to reductions in diversity. This issue--commonly referred to as the diversity-stability debate--is the subject of this review, which synthesizes historical ideas with recent advances. Both theory and empirical evidence agree that we should expect declines in diversity to accelerate the simplification of ecological communities.

The diversity–stability debate

Genetic diversity is one of the three forms of biodiversity recognized by the World Conservation Union (IUCN) as deserving conservation. The need to conserve genetic diversity within populations is based on two arguments: the necessity of genetic diversity for evolution to occur, and the expected relation- ship between heterozygosity and population fitness. Because loss of genetic diversity is related to inbreed- ing, and inbreeding reduces reproductive fitness, a correlation is expected between heterozygosity and pop- ulation fitness. Long-term effective population size, which determines rates of inbreeding, should also be correlated with fitness. However, other theoretical considerations and empirical observations suggest that the correlation between fitness and heterozygosity may be weak or nonexistent. We used all the data sets we could locate (34) to perform a meta-analysis and resolve the issue. Data sets were included in the study, provided that fitness, or a component of fitness, was measured for three or more populations along with heterozygosity, heritability, and/or population size. The mean weighted correlation between measures of genetic diversity, at the population level, and population fitness was 0.4323. The correlation was highly sig- nificant and explained 19% of the variation in fitness. Our study strengthens concerns that the loss of het- erozygosity has a deleterious effect on population fitness and supports the IUCN designation of genetic di- versity as worthy of conservation.

Correlation between Fitness and Genetic Diversity

http://webpages.icav.up.pt/PTDC/BIA-BEC/099934/2008/papers/Frankham_2005_Biological_Conservation.pdf

Genetics and extinction

The 1990s may be the last decade during which constructive and creative decisions, activities, and investments can be made to ensure that many of the world's species and ecosystems are maintained, examined for their material and ecological value, and promoted for sustainable use to support new and innovative approaches to development. The combination of maintaining the maximum possible biological and cultural diversity, and the greatest possible scientific endeavor seems the most sensible approach toward dealing with the dynamic future facing humanity. The elements now exist that will reverse the trend toward the biotic impoverishment of the world. New partners in conservation need to be found, involving all ministries, departments, and private institutions that are directly dependent on biological resources. For example, national parks departments should be joined in habitat management by a wide range of other institutions to represent all interests. Furthermore, other line agencies need to develop the capacity to manage biodiversity of particular relevance to their respective missions. Actions taken in the next few years will determine whether we take a road toward a chaotic future characterized by overexploitation and abuse of our biological resources, or take the road toward maintaining greater biological diversity and resource sustainability.

Conserving the World's Biological Diversity

This book offers an overview of where the worlds species and genetic resources are located why they are valuable and a new analysis of species extinctions in tropical forests; presents a survey of the most recent findings of conservation biology; and suggests how these findings can be applied. The report ends by emphasizing the interdependence between biological diversity and human cultural diversity and the policy implications of this critical bond. The single greatest cause of species extinction is tropical deforestation where 50% of the estimated 10 million species on earth are being destroyed at the rate of 5-10% per decade. Freshwater river habitats and tropical islands are also losing species rapidly through habitat conversion and species introduction. Species can only be managed effectively by preserving habitats. The inevitable human population growth will increase demands on habitats as well as the need for biological diversity. The cost of not addressing this problem will be higher than setting management in motion. The solution is largely political; fund research put biodiversity conservation into development priorities encourage integrated regional and cross-sectoral coordination establish national priorities and promote biocultural conservation.

Keeping Options Alive: The Scientific Basis for Conserving Biodiversity

National parks, conservation and development : the role of protected areas in sustaining society : proceedings of the World Congress on National Parks, Bali, Indonesia, 11-22 October 1982

(1990). Strategies for Conserving Biodiversity. Environment: Science and Policy for Sustainable Development: Vol. 32, No. 3, pp. 16-40.

Strategies for Conserving Biodiversity

The authors would like to extend their thanks to Terry Jeggle and Allan Lavell for commenting on advanced drafts, as well as to Catherine Marie Hunt for her help in editing and revising the final draft.

Kenton R. Miller

Papers

Conserving the World's Biological Diversity

Keeping Options Alive: The Scientific Basis for Conserving Biodiversity

National parks, conservation and development : the role of protected areas in sustaining society : proceedings of the World Congress on National Parks, Bali, Indonesia, 11-22 October 1982

Strategies for Conserving Biodiversity

IUCN—The World Conservation Union