Morphological correlates of community structure in North American waterfowl

DuBowy, P. J. (2000) Morphological correlates of community structure in North American waterfowl. Community Ecology, 1 (2). pp. 147-156. ISSN 1585-8553

Preview

Text comec.1.2000.2.4.pdf Download (330kB) | Preview

Abstract

I consider relationships between functional feeding morphology and feeding ecology within a guild of dabbling ducks (Anas spp.) which co-occur year round. This waterfowl guild contains three .core. species with typical bill morphologies and four .peripheral. species which vary from the typical morphology in bill length and width or interlamellar spacing. Nearest neighbors in morphological space tend to have high ecological (dietary) overlap; i.e., similarity in morphology corresponds to similarity in ecology. Moreover, by employing Monte Carlo techniques, correlations between morphology and ecology are shown to be weaker during winter than summer, implying that species overcompensate. during winter and reduce dietary overlap even more than would be expected by similarities in bill morphology alone. Additionally, I examine morphological variation among populations of North American mallards (A. platyrhynchos) to test Roughgarden.s (1974) predictions regarding relationships between intraspecific morphological variation and interspecific competition. Specifically, morphological variation should decrease with either an increase in number of competing species or a decrease in available resources. Although populations show expected trends in bill morphology with sex (males have larger bills than females) and latitude (Bergmann.s rule), I am able to demonstrate only a weak trend in females in relationship between morphological variation and intensity of interspecific competition. Examinations of relationships between morphology and ecology should be considered during that time of year when ecological .' crunches' occur, as this should be when selection for different morphologies and feeding strategies occurs, although species may utilize other mechanisms (e.g., foraging behavior, habitat selection) which could mediate resource partitioning to a greater degree than would be expected solely by morphological differences.

Actions (login required)

Edit Item