title: Density, climate and varying return points: an analysis of long-term population fluctuations in the threatened European tree frog.
abstract: Experimental research has identified many putative agents of amphibian decline, yet the population-level consequences of these agents remain unknown, owing to lack of information on compensatory density dependence in natural populations. Here, we investigate the relative importance of intrinsic (density-dependent) and extrinsic (climatic) factors impacting the dynamics of a tree frog (Hyla arborea) population over 22 years. A combination of log-linear density dependence and rainfall (with a 2-year time lag corresponding to development time) explain 75% of the variance in the rate of increase. Such fluctuations around a variable return point might be responsible for the seemingly erratic demography and disequilibrium dynamics of many amphibian populations.
authors.affiliation: Laboratory for Conservation Biology, Department of Ecology and Evolution, University of Lausanne, Biology Building, 1015, Dorigny, Switzerland. jerome.pellet@amaibach.ch
authors.forename: Jérôme
authors.initials: J
authors.lastname: Pellet
authors.forename: Benedikt R
authors.initials: BR
authors.lastname: Schmidt
authors.forename: Fabien
authors.initials: F
authors.lastname: Fivaz
authors.forename: Nicolas
authors.initials: N
authors.lastname: Perrin
authors.forename: Kurt
authors.initials: K
authors.lastname: Grossenbacher
mesh_terms: D000818:Animals; D001001:Anura / Q000502:physiology*; D002980:Climate; D003247:Conservation of Natural Resources / Q000706:statistics & numerical data; D017753:Ecosystem; D008137:Longitudinal Studies; D008962:Models, Theoretical; D011156:Population Density; D011157:Population Dynamics; D013557:Switzerland