Journal ArticleDOI
Factors Affecting Population Fluctuations in Larval and Adult Stages of the Wood Frog (Rana Sylvatica)
TLDR
The population appeared to be regulated through density-dependent factors affecting larval survival, larval size, and time of metamorphosis, as well as adult population size, which also affected total clutch volume.Abstract:
During a 7-yr population study on the wood frog, Rana sylvatica, the breed- ing population size fluctuated by a factor of 10 and juvenile production by a factor of 100. Variation in the adult population among years was largely due to variation in juvenile recruitment. Annual net replacement rates (Ro) varied from 0.009 to 7.49. Survivorship curves (calculated using the number of eggs deposited as the initial point) showed that most variation in the proportion of individuals surviving to adulthood was due to variation in larval survival; juvenile and adult survival was relatively constant among years. Male and female survival did not differ. Because females matured a year later than males, on average 2.3 times as many males as females from a given clutch survived to breed. This difference accounted for the observed male-biased sex ratio in breeding choruses. Pre- metamorphic survival and size at metamorphosis were negatively correlated with the number of eggs deposited. Length of larval period was positively correlated with number of eggs deposited. Survival was higher among juveniles that metamorphosed early and were large at metamorphosis. Larger juveniles matured earlier and were also larger as adults. The population appeared to be regulated through density-dependent factors affecting larval survival, larval size, and time of metamorphosis. Adult population size also nega- tively affected total clutch volume. Mean monthly rainfall positively affected adult survival.read more
Citations
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Journal ArticleDOI
Food Web Complexity and Community Dynamics
Gary A. Polis,Donald R. Strong +1 more
TL;DR: It is concluded that trophic cascades and top-down community regulation as envisioned by trophIC-level theories are relatively uncommon in nature.
Journal ArticleDOI
Global Amphibian Declines: A Problem in Applied Ecology
Ross A. Alford,Stephen Richards +1 more
TL;DR: The results suggest that most amphibian populations should decrease more often than they increase, due to highly variable recruitment and less variable adult mortality.
Journal ArticleDOI
Amphibian Declines: Judging Stability, Persistence, and Susceptibility of Populations to Local and Global Extinctions
TL;DR: It is suggested that many amphibian populations may be unable to recolonize areas after local extinction, due to the physiological constraints, relatively low mobility, and site fidelity of amphibians.
Journal ArticleDOI
Declining Amphibian Populations: The Problem of Separating Human Impacts from Natural Fluctuations
Joseph H. K. Pechmann,David E. Scott,Raymond D. Semlitsch,Janalee P. Caldwell,Laurie J. Vitt,J. Whitfield Gibbons +5 more
TL;DR: Data from 1979 to 1990 for three salamander species and one frog species at a breeding pond in South Carolina showed fluctuations of substantial magnitude in both the size of breeding populations and in recruitment of juveniles, illustrating that to distinguish between natural population fluctuations and declines with anthropogenic causes may require long-term studies.
Journal ArticleDOI
Metapopulation Dynamics and Amphibian Conservation
David M. Marsh,Peter C. Trenham +1 more
TL;DR: Future efforts need to determine the mechanisms underlying patterns of abundance and distributional change and patterns in amphibian pop- ulations, and effective conservation strategies must successfully balance metapopulation with careful attention to local habitat quality.
References
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Journal ArticleDOI
Time and size at metamorphosis related to adult fitness in Ambystoma talpoideum
TL;DR: Results demonstrate a direct relationship between phenotypic variation generated in the larval stage and adult traits closely associated with an individual's fitness.
Journal ArticleDOI
Interpreting Geographic Variation in Life-History Traits
Keith A. Berven,Douglas E. Gill +1 more
TL;DR: Heritability and survivorship data support the general notion that fitness traits should have low levels of additive genetic variation, but also suggest that antagonistic pleiotropy may act to preserve genetic variation in fitness traits under simultaneous selection.
Journal ArticleDOI
Predation, Competition, and the Composition of Larval Anuran Guilds
TL;DR: Results indicate that predators mediated interspecific competition among larval anurans in the absence of predators, and intermediate values of Notophthalmus density maximized the total production of anuran metamorph biomass.
Journal ArticleDOI
Tadpoles, Predation and Pond Habitats in the Tropics
TL;DR: A model is proposed to illustrate the relationship between pond complexity and predation as they affect the species composition of a tadpole community and the predatory feeding mode of tadpoles is considered in light of this model.
Journal ArticleDOI
Factors Controlling Tadpole Populations of the Chorus Frog (Pseudacris Triseriata) on Isle Royale, Michigan
TL;DR: The results demonstrate density dependence and indicate that food is limiting and in short supply in the natural breeding pools of P. triseriata and suggest that population control may be common to other anurans of ephemeral habitats.