Ecological correlates of anuran breeding activity and community structure

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Title: Ecological correlates of anuran breeding activity and community structure
Author: Saenz, Daniel
Abstract: Multiple ecological factors can simultaneously affect species activity and community structure . The goal of my dissertation was to examine the effects of abiotic factors , biotic factors , and succession on anuran communities . I took a three pronged approach dividing the study into three major chapters . First I focused on abiotic factors that affect anuran breeding activity . I found that weather , rainfall and temperature affect the breeding activity of each species differently , and species in my study area can be placed into 5 different groups based on their association with weather and season : 1 ) breed within a predictable season (summer ) independent of local weather patterns 2 ) breed opportunistically within a predictable season (summer ) dependent on local rainfall 3 ) breed opportunistically within a predictable season (winter ) dependent on local temperature 4 ) breed opportunistically dependent on local flood level rainfall events and 5 ) breed opportunistically year round dependent on local temperature in the winter and local rainfall in the summer . In the second part of the study , I created a simulation model of an anuran community using published life history parameters of the anuran species in my study system . Results of the model suggest colonizing ability is important for species with low fecundity and high susceptibility to predation . These early succession species tend to be constrained from later stages of succession by predators . Species that are resistant to predators are generally poor colonizers and tend to arrive late in succession , but once they colonize a pond they tend to persist and recruit successfully . Finally , I explored biotic mechanisms that might be important in structuring anuran communities . I found that with the exception of Rana sphenocephala , anuran species occupying sites with shorter hydroperiods had higher activity rates and were more susceptible to predation . Rana sphenocephala appeared to be better at escaping predation than the other species despite a relatively high activity rate . Examination of published phylogenies indicates R . sphenocephala is derived from a species group that uses permanent water suggesting that R . sphenocephala has retained many anti -predator defenses inherited from its ancestors , even though the species now exploits sites with low predator densities .
URI: http : / /hdl .handle .net /1969 .1 /1575
Date: 2005-02-17

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Ecological correlates of anuran breeding activity and community structure. Available electronically from http : / /hdl .handle .net /1969 .1 /1575 .

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