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 impacts of roads and other infrastructure on mammal and bird populations: a meta-analysis.

Landscape Ecology in Theory and Practice

Sexes play different roles in reproduction and the adaptive significance of the often remarkably distinct morphologies of adult males and females is documented frequently. Yet, in most vertebrates, the sexes are nearly identical in morphology during early development and undergo highly divergent growth to achieve different adult sizes. The mechanisms that enable the virtually genetically identical sexes to have such divergent growth are not well understood. Of special interest are the constraints that a shared gene pool imposes on sex-specific modifications of growth and the ways that males and females overcome these constraints in response to divergent selection pressures. Recent studies show that the rapid evolution of sex-specific developmental regulators and modifiers can produce sexual dimorphism in size whilst maintaining the integrity of the developmental program that is shared between the sexes.

/pdf/growing-apart-an-ontogenetic-perspective-on-the-evolution-of-1gsgpvldt2.pdf

Growing apart: an ontogenetic perspective on the evolution of sexual size dimorphism

Among Earth's most stunning, yet imperiled, biological phenomena is long-distance migration (LDM). Although the understanding of how and why animals migrate may be of general interest, few site- specific strategies have targeted ways in which to best retain such increasingly rare events. Contrasts among 29 terrestrial mammals from five continents representing 103 populations indicate that remnant long-distant migrants have poor long-term prospects. Nonetheless, in areas of low human density in the Western Hemi- sphere, five social and nongregarious species, all from the same region of the Rocky Mountains (U.S.A.), still experience the most accentuated of remaining New World LDMs south of central Canada. These movements occur in or adjacent to the Greater Yellowstone region, where about 75% of the migration routes for elk (Cervus elaphus), bison ( Bison bison), and North America's sole surviving endemic ungulate, pronghorn (Antilocapra americana), have already been lost. However, pronghorn still migrate up to 550 km (round-trip) annually. These extreme movements (1) necessitate use of historic, exceptionally narrow corridors (0.1-0.8 km wide) that have existed for at least 5800 years, (2) exceed travel distances of elephants ( Loxodonta africana) and zebras ( Equus burchelli), and (3) are on par with those of Asian chiru ( Pantholops hodgsoni) and African wildebeest (Connochaetes taurinus). Although conservation planners face uncertainty in situating reserves in the most biologically valued locations, the concordance between archaeological and current biological data on migration through specific corridors in these unprotected areas adjacent to the Yellowstone system high- lights their retention value. It is highly likely that accelerated leasing of public lands for energy development in such regions will truncate such migrations. One landscape-level solution to conserving LDMs is the creation of a network of national migration corridors, an action in the Yellowstone region that would result in de facto protection for a multispecies complex. Tactics applied in this part of the world may not work in others, however, therefore reinforcing the value of site-specific field information on the past and current biological needs of migratory species.

The Last Mile: How to Sustain Long-Distance Migration in Mammals

Habitat selection is the disproportionate use of available conditions and resources, and involves responses in space and time to perceived risks and rewards. It frequently depends on the scale of measurement, often in non-linear ways that preclude simple extrapolation across scales. More critically, animals often select different habitat components at different scales, and species vary in their scales of selection. Although multi-scaled research on habitat selection has proliferated, synthesis of this work has been impeded by imprecise terminology and arbitrarily defined analytical scales. Here, we review key concepts and findings and evaluate future prospects opened up in part by new technologies that enable novel and more efficient data collection. Innovative measurement, combined with novel analytical approaches, permits habitat selection to be investigated across a broad continuum of scales. By linking habitat selection to fitness as a function of scale, use-of-habitat assessments can be more effective. The fitness costs and benefits of habitat selection change with scale; the scales of habitat selection may inform us of limiting factors. We outline how reward/risk ratios can be used to assess the fitness implications of habitat selection across scales.

https://faculty.washington.edu/cet6/pub/Temp/CFR521e/Mayor_etal_2009.pdf

Habitat selection at multiple scales

Hydroelectric development and the disruption of migration in caribou

Several studies have shown that habitat selection and population limitation of woodland caribou (Rangifer tarandus caribou) is typically associated with the interaction among human-induced habitat ...

Habitat selection and demography of a nonmigratory woodland caribou population in Newfoundland

In many vertebrates size is one of the most influential and variable individual characteristics and a strong determinant of reproductive success. Body size is generally density dependent and decreases when intraspecific competition increases. Frequent and long-distance movements increase energy expenditures and, therefore, may also influence body size, particularly in highly mobile species. Caribou (Rangifer tarandus, also known as reindeer) exhibit tremendous variation in size and movements and thus represent an excellent candidate species to test the relationships between body size, population size, and movements. We analyzed body measurements of adult female caribou from 7 herds of the Quebec-Labrador Peninsula, Canada, and we related their morphology to population size, movements, and annual ranges. The herds represented 3 ecotypes (migratory, montane, and sedentary). Ecotypes and herds differed in size (length), shape (roundness), and movements. The sedentary ecotype was larger and moved 4 to 7 times less than the migratory ecotype in the 1990s. At the start of a demographic growth period in the early 1960s, migratory caribou from the Riviere-George (hereafter George) herd had longer mandibles than caribou of the sedentary ecotype. Mandible length in the George herd declined in the 1980s after rapid population growth, while individuals performed extensive movements and the herd's annual range increased. Migratory caribou then became shorter than sedentary caribou. After the George herd decline in the 1990s, mandible length increased again near levels of the 1980s. Caribou from the migratory Riviere-aux-Feuilles herd later showed a similar decline in mandible length during a period of population growth, associated with longer movements and increasing annual range. We hypothesize that the density-dependent effect observed on body size might have been exerted through summer habitat degradation and movement variations during herd growth. Our study has 2 important implications for caribou management: the distinctiveness of different populations and ecotypes, and the correlations between population trajectories and changes in body condition and habitat.

https://www.caribou-ungava.ulaval.ca/fileadmin/documents/Articles_PDF/Couturier_et_al._2010_JWM.pdf

Body Size Variations in Caribou Ecotypes and Relationships With Demography

Long-term studies of demography and movements are rare but critical to understanding long-lived mobile mammals like caribou (Rangifer tarandus). We studied changes in the abundance, vital rates, body size, and timing of migration of the Buchans Plateau caribou herd in Newfoundland, Canada. From the early 1960s to 2000, the population grew at 6.5%/year, although survival and recruitment indicated a declining growth rate (1.4%) by the late 1990s. The numerical increase was negatively associated with other population attributes. Rates of parturition, survival to 6 months of age, and recruitment diminished significantly. Adults exhibited substantial decreases in body size. Spring migration was significantly later and autumn migration significantly earlier. We surmise that these responses may reflect heightened density-dependent competition for summer forage.

Shane P. Mahoney

Papers

Habitat selection at multiple scales

Hydroelectric development and the disruption of migration in caribou

Habitat selection and demography of a nonmigratory woodland caribou population in Newfoundland

Body Size Variations in Caribou Ecotypes and Relationships With Demography

Long-term changes in demography and migration of newfoundland caribou