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Density dependent growth in adult brown frogs Rana arvalis and Rana temporaria - A field experiment

Loman, Jon LU and Lardner, Björn LU (2009) In Acta Oecologica 35(6). p.824-830
Abstract
In species with complex life cycles, density regulation can operate on any of the stages. in frogs there are almost no studies of density effects on the performance of adult frogs in the terrestrial habitat. We therefore studied the effect of summer density on the growth rate of adult frogs during four years. Four 30 by 30 m plots in a moist meadow were used. In early summer, when settled after post-breeding migration, frogs (Rana arvalis and Rana temporaria that have a very similar ecology and potentially compete) were enclosed by erecting a fence around the plots. Frogs were captured, measured, marked and partly relocated to create two high density and two low density plots. In early autumn the frogs were again captured and their... (More)
In species with complex life cycles, density regulation can operate on any of the stages. in frogs there are almost no studies of density effects on the performance of adult frogs in the terrestrial habitat. We therefore studied the effect of summer density on the growth rate of adult frogs during four years. Four 30 by 30 m plots in a moist meadow were used. In early summer, when settled after post-breeding migration, frogs (Rana arvalis and Rana temporaria that have a very similar ecology and potentially compete) were enclosed by erecting a fence around the plots. Frogs were captured, measured, marked and partly relocated to create two high density and two low density plots. In early autumn the frogs were again captured and their individual summer growth determined. Growth effects were evaluated in relation to two density measures: density by design (high/low manipulation), and actual (numerical) density. R. arvalis in plots with low density by design grew faster than those in high density plots. No such effect was found for R. temporaria. For none of the species was growth related to actual summer density, determined by the Lincoln index and including the density manipulation. The result suggests that R. arvalis initially settled according to an ideal free distribution and that density had a regulatory effect (mediated through growth). The fact that there were no density effects on R. temporaria (and a significant difference in its response to that of R. arvalis) suggests it is a superior competitor to R. arvalis during the terrestrial phase. There were no density effects on frog condition index, suggesting that the growth rate modifications may actually be an adaptive trait of R. arvalis. The study demonstrates that density regulation may be dependent on resources in frogs' summer habitat. (C) 2009 Elsevier Masson SAS. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Population regulation, Amphibians, Competition, Terrestrial habitat
in
Acta Oecologica
volume
35
issue
6
pages
824 - 830
publisher
Elsevier
external identifiers
  • wos:000271969500008
  • scopus:70350135250
ISSN
1146-609X
DOI
10.1016/j.actao.2009.08.011
language
English
LU publication?
yes
id
cb5b770c-053d-4845-a130-7193fbf37236 (old id 1518569)
date added to LUP
2009-12-28 15:05:48
date last changed
2017-05-21 04:03:32
@article{cb5b770c-053d-4845-a130-7193fbf37236,
  abstract     = {In species with complex life cycles, density regulation can operate on any of the stages. in frogs there are almost no studies of density effects on the performance of adult frogs in the terrestrial habitat. We therefore studied the effect of summer density on the growth rate of adult frogs during four years. Four 30 by 30 m plots in a moist meadow were used. In early summer, when settled after post-breeding migration, frogs (Rana arvalis and Rana temporaria that have a very similar ecology and potentially compete) were enclosed by erecting a fence around the plots. Frogs were captured, measured, marked and partly relocated to create two high density and two low density plots. In early autumn the frogs were again captured and their individual summer growth determined. Growth effects were evaluated in relation to two density measures: density by design (high/low manipulation), and actual (numerical) density. R. arvalis in plots with low density by design grew faster than those in high density plots. No such effect was found for R. temporaria. For none of the species was growth related to actual summer density, determined by the Lincoln index and including the density manipulation. The result suggests that R. arvalis initially settled according to an ideal free distribution and that density had a regulatory effect (mediated through growth). The fact that there were no density effects on R. temporaria (and a significant difference in its response to that of R. arvalis) suggests it is a superior competitor to R. arvalis during the terrestrial phase. There were no density effects on frog condition index, suggesting that the growth rate modifications may actually be an adaptive trait of R. arvalis. The study demonstrates that density regulation may be dependent on resources in frogs' summer habitat. (C) 2009 Elsevier Masson SAS. All rights reserved.},
  author       = {Loman, Jon and Lardner, Björn},
  issn         = {1146-609X},
  keyword      = {Population regulation,Amphibians,Competition,Terrestrial habitat},
  language     = {eng},
  number       = {6},
  pages        = {824--830},
  publisher    = {Elsevier},
  series       = {Acta Oecologica},
  title        = {Density dependent growth in adult brown frogs Rana arvalis and Rana temporaria - A field experiment},
  url          = {http://dx.doi.org/10.1016/j.actao.2009.08.011},
  volume       = {35},
  year         = {2009},
}