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

The most unique feature of Earth is the existence of life, and the most extraordinary feature of life is its diversity. Approximately 9 million types of plants, animals, protists and fungi inhabit the Earth. So, too, do 7 billion people. Two decades ago, at the first Earth Summit, the vast majority of the world's nations declared that human actions were dismantling the Earth's ecosystems, eliminating genes, species and biological traits at an alarming rate. This observation led to the question of how such loss of biological diversity will alter the functioning of ecosystems and their ability to provide society with the goods and services needed to prosper.

/pdf/biodiversity-loss-and-its-impact-on-humanity-2d0fgc88mg.pdf

Biodiversity loss and its impact on humanity

Just over one hundred and thirty years ago Charles Darwin, in The Descent of Man and Selection in Relation to Sex (1871), developed remarkably accurate conclusions about man's ancestry, based on a review of general comparative anatomy and psychology in which he regarded sexual selection as a necessary part of the evolutionary process. But the attention of biologists turned to the more general concept of natural selection, in which sexual selection plays a complex role that has been little understood. This volume significantly broadens the scope of modern evolutionary biology by looking at this important and long neglected concept of great importance. In this book, which is the first full discussion of sexual selection since 1871, leading biologists bring modern genetic theory and behavior observation to bear on the subject. The distinguished authors consider many aspects of sexual selection in many species, including man, within the context of contemporary evolutionary theory and research. The result is a remarkably original and well-rounded view of the whole concept that will be invaluable especially to students of evolution and human sexual behavior. The lucid authority of the contributors and the importance of the topic will interest all who share in man's perennial fascination with his own history. The book will be of central importance to a wide variety of professionals, including biologists, anthropologists, and geneticists. It will be an invaluable supplementary text for courses in vertebrate biology, theory of evolution, genetics, and physical anthropology. It is especially important with the emergence of alternative explanations of human development, under the rubric of creationism and doctrines of intelligent design.

/pdf/sexual-selection-and-the-descent-of-man-1871-1971-446kq7o7lj.pdf

Sexual selection and the descent of man, 1871-1971

Mating systems, philopatry and dispersal in birds and mammals

Understanding the negative and positive effects of agricultural land use for the conservation of biodiversity, and its relation to ecosystem services, needs a landscape perspective. Agriculture can contribute to the conservation of high-diversity systems, which may provide important ecosystem services such as pollination and biological control via complementarity and sampling effects. Land-use management is often focused on few species and local processes, but in dynamic, agricultural landscapes, only a diversity of insurance species may guarantee resilience (the capacity to reorganize after disturbance). Interacting species experience their surrounding landscape at different spatial scales, which influences trophic interactions. Structurally complex landscapes enhance local diversity in agroecosystems, which may compensate for local high-intensity management. Organisms with high-dispersal abilities appear to drive these biodiversity patterns and ecosystem services, because of their recolonization ability and larger resources experienced. Agri-environment schemes (incentives for farmers to benefit the environment) need to broaden their perspective and to take the different responses to schemes in simple (high impact) and complex (low impact) agricultural landscapes into account. In simple landscapes, local allocation of habitat is more important than in complex landscapes, which are in total at risk. However, little knowledge of the relative importance of local and landscape management for biodiversity and its relation to ecosystem services make reliable recommendations difficult.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1461-0248.2005.00782.x

Landscape perspectives on agricultural intensification and biodiversity – ecosystem service management

Publisher Summary This chapter summarizes the current information on population cycles in small rodents It first looks at the general questions about cycles, and then discusses the demographic machinery which drives the changes in numbers And finally, analyzes the current theories which explain population cycles in rodents Population cycles in voles and lemmings are accompanied by a series of changes A few of them include fluctuations occurring in a variety of genera and species from arctic to temperate areas, from Mediterranean to continental climates, from snowy areas to snow-free areas Populations living in a wide variety of plant communities in a small geographic area all fluctuate in the same way, often in phase Survival of adult males fluctuates independently of that of adult females, when viewed on a weekly time scale Males may suffer heavy losses in the decline for a few weeks when females are surviving very well, and vice versa

Population Cycles in Small Mammals

While the proportion of cases in which induced responses act as defenses against herbivores may be uncertain, we would like to consider in this review the characteristics of changes that relate to their role as defenses. What are the changes, why and how might they occur, and what might be done to further understand their influence on plant-herbivore interactions?

http://www.sysecol2.ethz.ch/Refs/EntClim/K/Ka044_S.pdf

Induced Plant Responses to Herbivory

Invasions of nonindigenous species threaten native biodiversity, ecosystem functioning, animal and plant health, and human economies. The best solution is to prevent the introduction of exotic organisms but, once introduced, eradication might be feasible. The potential ecological and social ramifications of eradication projects make them controversial; however, these programs provide unique opportunities for experimental ecological studies. Deciding whether to attempt eradication is not simple and alternative approaches might be preferable in some situations.

https://www.cell.com/trends/ecology-evolution/pdf/S0169-5347(00)01914-5.pdf

Eradication revisited: dealing with exotic species.

https://www.zoology.ubc.ca/~myers/citations/denoth.pdf

Multiple agents in biological control: improving the odds?

We conclude that population fluctuations in Microtus in southern Indiana are produced by a syndrome of changes in birth and death rates similar to that found in other species of voles and lemmings. The mechanisms which cause the changes in birth and death rates are demolished by fencing the population so that no dispersal can occur. Dispersal thus seems critical for population regulation in Microtus. Because most dispersal occurs during the increase phase of the population cycle and there is little dispersal during the decline phase, dispersal is not directly related to population density. Hence the quality of dispersing animals must be important, and we have found one case of increased dispersal tendency by one genotype. The failure of population regulation of Microtus in enclosed areas requires an explanation by any hypothesis attempting to explain population cycles in small rodents. It might be suggested that the fence changed the predation pressure on the enclosed populations. However, the fence was only 2 feet (0.6 meter) high and did not stop the entrance of foxes, weasels, shrews, or avian predators. A striking feature was that the habitat in the enclosures quickly recovered from complete devastation by the start of the spring growing season. Obviously the habitat and food quality were sufficient to support Microtus populations of abnormally high densities, and recovery of the habitat was sufficiently quick that the introduction of new animals to these enclosed areas resulted in another population explosion. Finally, hypotheses of population regulation by social stress must account for the finding that Microtus can exist at densities several times greater than normal without "stress" taking an obvious toll. We hypothesize that the prevention of dispersal changes the quality of the populations in the enclosures in comparison to those outside the fence. Voles forced to remain in an overcrowded fenced population do not suffer high mortality rates and continue to reproduce at abnormally high densities until starvation overtakes them. The initial behavioral interactions associated with crowding do not seem sufficient to cause voles to die in situ. What happens to animals during the population decline? Our studies have not answered this question. The animals did not appear to disperse, but it is possible that the method we used to measure dispersal (movement into a vacant habitat) missed a large segment of dispersing voles which did not remain in the vacant area but kept on moving. Perhaps the dispersal during the increase phase of the population cycle is a colonization type of dispersal, and the animals taking part in it are likely to stay in a new habitat, while during the population decline dispersal is a pathological response to high density, and the animals are not attracted to settling even in a vacant habitat. The alternative to this suggestion is that animals are dying in situ during the decline because of physiological or genetically determined behavioral stress. Thus the fencing of a population prevents the change in rates of survival and reproduction, from high rates in the increase phase to low rates in the decline phase, and the fenced populations resemble "mouse plagues." A possible explanation is that the differential dispersal of animals during the phase of increase causes the quality of the voles remaining at peak densities in wild populations to be different from the quality of voles at much higher densities in enclosures. Increased sensitivity to density in Microtus could cause the decline of wild populations at densities lower than those reached by fenced populations in which selection through dispersal has been prevented. Fencing might also alter the social interactions among Microtus in other ways that are not understood. The analysis of colonizing species by MacArthur and Wilson (27) can be applied to our studies of dispersal in populations of Microtus. Groups of organisms with good dispersal and colonizing ability are called r strategists because they have high reproductive potential and are able to exploit a new environment rapidly. Dispersing voles seem to be r strategists. Young females in breeding condition were over-represented in dispersing female Microtus (17). The Tf(C)/Tf(E) females, which were more common among dispersers during the phase of population increase (Fig. 6), also have a slight reproductive advantage over the other Tf genotypes (19). Thus in Microtus populations the animals with the highest reproductive potential, the r strategists, are dispersing. The segment of the population which remains behind after the selection-via-dispersal are those individuals which are less influenced by increasing population densities. These are the individuals which maximize use of the habitat, the K strategists in MacArthur and Wilson's terminology, or voles selected for spacing behavior. Thus we can describe population cycles in Microtus in the same theoretical framework as colonizing species on islands. Our work on Microtus is consistent with the hypothesis of genetic and behavioral effects proposed by Chitty (6) (Fig. 7) in that it shows both behavioral differences in males during the phases of population fluctuation and periods of strong genetic selection. The greatest gaps in our knowledge are in the area of genetic-behavioral interactions which are most difficult to measure. We have no information on the heritability of aggressive behavior in voles. The pathways by which behavioral events are translated into physiological changes which affect reproduction and growth have been carefully analyzed by Christian and his associates (28) for rodents in laboratory situations, but the application of these findings to the complex field events described above remains to be done. Several experiments are suggested by our work. First, other populations of other rodent species should increase to abnormal densities if enclosed in a large fenced area (29). We need to find situations in which this prediction is not fulfilled. Island populations may be an important source of material for such an experiment (30). Second, if one-way exit doors were provided from a fenced area, normal population regulation through dispersal should occur. This experiment would provide another method by which dispersers could be identified. Third, if dispersal were prevented after a population reached peak densities, a normal decline phase should occur. This prediction is based on the assumption that dispersal during the increase phase is sufficient to ensure the decline phase 1 or 2 years later. All these experiments are concerned with the dispersal factor, and our work on Microtus can be summarized by the admonition: study dispersal.

https://science.sciencemag.org/content/sci/179/4068/35.full.pdf

Judith H. Myers

Papers

Population Cycles in Small Mammals

Induced Plant Responses to Herbivory

Eradication revisited: dealing with exotic species.

Multiple agents in biological control: improving the odds?

Population Cycles in Small Rodents