Walter D. Koenig

Detectability, philopatry, and the distribution of dispersal distances in vertebrates

Dispersal is of central importance to population biology, behavioral ecology and conservation. However, because field studies are based on finite study areas, nearly all dispersal distributions for vertebrates currently available are biased, often highly so. The inadequacy of dispersal data obtained directly by traditional methods using population studies of marked individuals is highlighted by comparing the resulting distributions with dispersal estimates obtained by radio-tracking and by using genetic estimates of gene flow.

Spatial autocorrelation of ecological phenomena

Ecological variables often fluctuate synchronously over wide geographical areas, a phenomenon known as spatial autocorrelation or spatial synchrony. Development of statistical approaches designed to test for spatial autocorrelation combined with the increasing accessibility of long-term, large-scale ecological datasets are now making it possible to document the patterns and understand the causes of spatial synchrony at scales that were previously intractable. These developments promise to foster significant future advances in understanding population regulation, metapopulation dynamics and other areas of population ecology.

Cooperative Breeding in Birds: long-term studies of ecology and behavior

Animals have evolved to behave in ways that maximize their reproductive success. This makes behavior that reduces their reproduction, but helps someone elses, di cult to understand. Possible solutions to this dilemma include helping relatives, improving the chance of inheriting a good reproductive position in the future, and maximizing access to resources. Examples of this phenomenon are particularly widespread within populations of birds engaged in cooperative breeding, where individuals heavily invest in rearing o spring that are not their own. Biological parents and one or more foster parents cooperate to raise a nests o spring. This helpful behavior results in a foster parent foregoing its opportunity to have progeny of its own during that breeding season. Despite this signi cant cost, there are many major bene ts to being a helper. This section will examine these bene ts and the ecological variables that determine whether or not an individual will participate in cooperative breeding. Author: Omar Metwalli

Ecology and evolution of cooperative breeding in birds

Introduction Walter D. Koenig and Janis L. Dickinson 1. Evolutionary origins J. David Ligon and D. Brent Burt 2. Delayed dispersal Jan Ekman, Janis L. Dickinson, Ben J. Hatchwell and Michael Griesser 3. Fitness consequences of helping Janis L. Dickinson and Ben J. Hatchwell 4. Parental care, load-lightening and costs Robert G. Heinsohn 5. Matings systems and sexual conflict Andrew Cockburn 6. Sex-ratio manipulation Jan Komdeur 7. Physiological ecology Morne Du Plessis 8. Endocrinology Steven J. Schoech, S. James Reynolds and Raoul K. Boughton 9. Incest and incest avoidance Walter D. Koenig and Joseph Haydock 10. Reproductive skew Robert D. Magrath, Rufus A. Johnstone and Robert G. Heinsohn 11. Joint-laying systems Sandra L. Vehrencamp and James S. Quinn 12. Conservation biology Jeffrey R. Walters, Caren B. Cooper, Susan J. Daniels, Gilberto Pasinelli and Karen Schiegg 13. Mammalian contrasts and comparisons Andrew F. Russell Summary Steven J. Pruett-Jones Names of bird and mammal species mentioned in the text References Index.

The Evolution of Delayed Dispersal in Cooperative Breeders

Why do the young of cooperative breeders-species in which more than two individuals help raise offspring at a single nest-delay dispersal and live in groups? Answering this deceptively simple question involves examining the costs and benefits of three alternative strategies: (1) dispersal and attempting to breed, (2) dispersal and floating, and (3) delayed dispersal and helping. If, all other things being equal, the fitness of individuals that delay dispersal is greater than the fitness of individuals that disperse and freed on their own, intrinsic benefits are paramount to the current maintenance of delayed dispersal. Intrinsic benefits are directly due to living with others and may include enhanced foraging efficienty and redudec susceptibility to predation. However, if individuals that disperse and attempt to breed in high-quality habitat achieve the highest fitness, extrinsic constraints on the ability of offspring to obtain such high-quality breeding opportunities force offspring to either delay dispersal or float. The relevant constraint to independent reproduction has frequently been termed habitat saturation. This concept, of itself, fails to explain the evolution of delayed dispersal. Instead, we propose the delayed-dispersal threshold model as a guide for organizing and evaluating the ecological factors potentially responsible for this phenomenon. We identify five parameters critical to the probability of delayed dispersal: relative population desnity, the fitness differential between early dispersal/breeding and delayed dispersal, the observed or hypothetical fitness of floaters, the distribution of territory quality, and spatiotemporal environmental variability. A key conclusion from the model is that no one factor by itself causes delayed dispersal and cooperative breeding. However, a difference in the dispersal patterns between two closely related species or populations (or between individuals in the same population in different years) may be attributable to one or a small set of factors. Much remains to be done to pinpoint the relative importance of different ecological factors in promoting delayed dispersal. This is underscored by our current inability to explain satisfactory several patterns including the relative significance of flooting, geographic biases in the incidence of cooperative breeding, sexual asymmetries in delayed dispersal, the relationship between delayed dispersal leading to helping behavior and cooperative polygamy, and the rarity of the co-occurrence of helpers and floaters within the same population. Advances in this field remain to be made along several fronts. In particular, we advocate experimental tests of specific ecological factors affecting the parameters of the delayed-dispersal threshold model, studies of noncooperatively breeding taxa focusing on what constraints to independent reproduction exist and why they do not result in delayed dispersal, and studies of intraspecific variation in group size and composition of cooperative breeders in relation to local habitat gradients and patchiness.

Patterns of Annual Seed Production by Northern Hemisphere Trees: A Global Perspective

We tested whether annual seed production (masting or mast fruiting) in Northern Hemisphere trees is an evolved strategy or a consequence of resource tracking by comparing masting patterns with those of annual rainfall and mean summer temperatures, two environmental variables likely to correlate with available resources. There were generally significant negative autocorrelations between the seed crop in year x and year \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape

Scale of mast-seeding and tree-ring growth

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SPATIALLY AUTOCORRELATED DEMOGRAPHY AND INTERPOND DISPERSAL IN THE SALAMANDER AMBYSTOMA CALIFORNIENSE

\end{document} (year \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape