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

Predicting the extinction of single populations or species requires ecological and evolutionary information. Primary demographic factors affecting population dynamics include social structure, life history variation caused by environmental fluctuation, dispersal in spatially heterogeneous environments, and local extinction and colonization. In small populations, inbreeding can greatly reduce the average individual fitness, and loss of genetic variability from random genetic drift can diminish future adaptability to a changing environment. Theory and empirical examples suggest that demography is usually of more immediate importance than population genetics in determining the minimum viable sizes of wild populations. The practical need in biological conservation for understanding the interaction of demographic and genetic factors in extinction may provide a focus for fundamental advances at the interface of ecology and evolution.

https://science.sciencemag.org/content/sci/241/4872/1455.full.pdf

Genetics and demography in biological conservation

Ecosystem services are natural processes that benefit humans. Birds contribute the four types of services recognized by the UN Millennium Ecosystem Assessment-provisioning, regulating, cultural, and supporting services. In this review, we concentrate primarily on supporting services, and to a lesser extent, provisioning and regulating services. As members of ecosystems, birds play many roles, including as predators, pollinators, scavengers, seed dispersers, seed predators, and ecosystem engineers. These ecosystem services fall into two subcategories: those that arise via behavior (like consumption of agricultural pests) and those that arise via bird products (like nests and guano). Characteristics of most birds make them quite special from the perspective of ecosystem services. Because most birds fly, they can respond to irruptive or pulsed resources in ways generally not possible for other vertebrates. Migratory species link ecosystem processes and fluxes that are separated by great distances and times. Although the economic value to humans contributed by most, if not all, of the supporting services has yet to be quantified, we believe they are important to humans. Our goals for this review are 1) to lay the groundwork on these services to facilitate future efforts to estimate their economic value, 2) to highlight gaps in our knowledge, and 3) to point to future directions for additional research.

Ecosystem Services Provided by Birds

The authors attempted a complete review of the empirical literature on effects of roads and traffic on animal abundance and distribution. They found 79 studies, with results for 131 species and 30 species groups. Overall, the number of documented negative effects of roads on animal abundance outnumbered the number of positive effects by a factor of 5; 114 responses were negative, 22 were positive, and 56 showed no effect. Amphibians and reptiles tended to show negative effects. Birds showed mainly negative or no effects, with a few positive effects for some small birds and for vultures. Small mammals generally showed either positive effects or no effect, mid-sized mammals showed either negative effects or no effect, and large mammals showed predominantly negative effects. The authors synthesized this information, along with information on species attributes, to develop a set of predictions of the conditions that lead to negative or positive effects or no effect of roads on animal abundance. Four species types are predicted to respond negatively to roads: (i) species that are attracted to roads and are unable to avoid individual cars; (ii) species with large movement ranges, low reproductive rates, and low natural densities; and (iii and iv) small animals whose populations are not limited by road-affected predators and either (a) avoid habitat near roads due to traffic disturbance or (b) show no avoidance of roads or traffic disturbance and are unable to avoid oncoming cars. Two species types are predicted to respond positively to roads: (i) species that are attracted to roads for an important resource (e.g., food) and are able to avoid oncoming cars, and (ii) species that do not avoid traffic disturbance but do avoid roads, and whose main predators show negative population-level responses to roads. Other conditions lead to weak or non-existent effects of roads and traffic on animal abundance. The authors identify areas where further research is needed, but they also argue that the evidence for population-level effects of roads and traffic is already strong enough to merit routine consideration of mitigation of these effects in all road construction and maintenance projects.

/pdf/effects-of-roads-on-animal-abundance-an-empirical-review-and-1lbgf8c4mw.pdf

Effects of Roads on Animal Abundance: an Empirical Review and Synthesis

http://www.dartmouth.edu/~mpayres/pubs/gepidem.PDF

Assessing the consequences of global change for forest disturbance from herbivores and pathogens.

The Red-cockaded Woodpecker: Surviving in a Fire-Maintained Ecosystem

/pdf/red-cockaded-woodpecker-colony-status-and-trends-on-the-2mxffbqold.pdf

Red-cockaded Woodpecker Colony Status and Trends On the Angelina, Davy Crockett and Sabine National Forests

Loss of mature forest habitat was measured around Red-cockaded Wood- pecker (Picoides borealis) cavity tree clusters (colonies) in three National Forests in eastern Texas. Forest removal results in a loss of foraging habitat and causes habitat fragmentation of the remaining mature forest. Habitat loss was negatively associated with woodpecker group size in small populations that had relatively isolated clusters but not in a larger, more dense population. Cutting patterns also may affect the amount of foraging habitat available to a family group if the group is forced to go through the territories of other groups to access suitable foraging habitat. Habitat loss may affect woodpecker group size by causing an

/pdf/forest-habitat-loss-fragmentation-and-red-cockaded-1rhb49cbxs.pdf

Forest habitat loss, fragmentation, and red-cockaded woodpecker populations

ABSTRACr.-We aged over 1350 Red-cockaded Woodpecker (Picoides borealis) cavity trees and a comparable number of randomly selected trees. Resulting data strongly support the hypothesis that Red-cockaded Woodpeckers preferentially select older trees. Ages of recently initiated cavity trees in the Texas study areas generally were similar to those of cavity trees initiated during the last several decades. In effect, the birds are continuing to select the oldest trees from a pool of trees of increasing age. This suggests that the current average age of cavity trees on these sites (85-130 yrs) may not provide optimum cavity trees for this endangered species. Received 15 July 1990, accepted 27 March 1991.

/pdf/cavity-tree-selection-by-red-cockaded-woodpeckers-in-35gr5p3aci.pdf

Cavity tree selection by red-cockaded woodpeckers in relation to tree age

Red-cockaded Woodpeckers (Picoides borealis) excavate resin wells in the immediate vicinity of roost and nest cavity entrances. Resin wells are worked regularly, resulting in a copious and persistent resin flow that coats the tree trunk, especially below cavity entrances. Red-cockaded Woodpeckers also scale loose bark from cavity trees and closely adjacent trees. These two behaviors result in smooth, sticky surfaces surrounding cavity entrances. Climbing experiments on cavity, scaled, and control trees using rat snakes (Elaphe obsoleta) demonstrate that these behaviors produce a resinous barrier that is highly effective in preventing predatory snakes from gaining access to active Red-cockaded Wood- pecker cavities. Received 23 Jan. 1989, accepted I5 May 1989. Red-cockaded Woodpeckers (Picoides borealis) and rat snakes (Elaphe obsoleta) are sympatric over an extensive area in the southeastern United States (Jackson 197 1, Conant 1985). Unique aspects of the behavioral biology of the Red-cockaded Woodpecker have been hypothesized as adaptations to reduce predation by rat snakes (Dennis 197 la, Ligon 1970). In this paper, we report experimental data supporting the hypothesis that cavity protection behavior, specifically when this behavior results in co- pious fresh resin accumulation adjacent to cavity entrances, significantly reduces the ability of rat snakes to climb Red-cockaded Woodpecker cavity trees. The Red-cockaded Woodpecker primarily inhabits mature pine forests over much of the southeastern United States (Jackson 197 1) where habitat alteration due to various management procedures has resulted in the species being placed on the Federal list of endangered species (Thompson and Baker 1971, Wood 1983). Southeastern pine forests, due to climate and the historical importance of fire, provide few dead trees and limbs for cavity construction by wood- peckers (Ligon 1970, 197 1). The Red-cockaded Woodpecker, unlike most other woodpecker species, uses living pines as cavity sites, with rare ex- ceptions (Ligon 1970, Patterson and Robertson 1983, Wayne 19 10). The selection of living pines, which produce copious resin flows when me- chanical damage occurs, places constraints on cavity location and archi- tecture. Cavities need to be located in trunk segments of sufficient diameter ,

https://sora.unm.edu/sites/default/files/journals/wilson/v102n01/p0014-p0022.pdf

D. Craig Rudolph

Papers

The Red-cockaded Woodpecker: Surviving in a Fire-Maintained Ecosystem

Red-cockaded Woodpecker Colony Status and Trends On the Angelina, Davy Crockett and Sabine National Forests

Forest habitat loss, fragmentation, and red-cockaded woodpecker populations

Cavity tree selection by red-cockaded woodpeckers in relation to tree age

Red-cockaded woodpeckers vs rat snakes: the effectiveness of the resin barrier