Subterranean environments are buffered from external climatic fluctuations due to the absence of light and a delayed thermal response to surface conditions(Mammola 2019).Terrestrial salamanders are often found in subt...Subterranean environments are buffered from external climatic fluctuations due to the absence of light and a delayed thermal response to surface conditions(Mammola 2019).Terrestrial salamanders are often found in subterranean habitats,but few studies have assessed the influence of climatic effects on their long-term spatial distribution and niche breadth.In this study,we investigated the variability over 29 consecutive years of the spatial niche in a terrestrial salamander population inhabiting an artificial subterranean habitat.We hypothesized that juvenile salamanders,which are typically active near cave entrances and more exposed to climatic variability and dehydration(Peterman et al.2013),would exhibit an earlier and more variable behavioral adaptation to increasing external temperatures compared to adults.展开更多
Ecological networks,usually depicting interactions among species,have been recently down-scaled to the individual level,permitting description of patterns of inter-individual resource variation that are usually hinder...Ecological networks,usually depicting interactions among species,have been recently down-scaled to the individual level,permitting description of patterns of inter-individual resource variation that are usually hindered at the species level.Optimal diet theory(ODT)models,applied to prey–predator systems,predict different patterns of nestedness and modularity in the network,depending on the available resources and intra-specific competition.The effect of resource availability on the emergence of networks structures,and ODT framework,has not yet fully been clarified.Here,we analyzed the structural patterns of individual-resource networks in 3 species of Mediterranean salamanders,in relation to changes in prey availability.We used weighted individual-resource network metrics to interpret the observed patterns,according to 3 ODT models.We found significant nestedness recurring in our study system,indicating that both selective and opportunistic individuals occur in the same population.Prey diversity,rather than abundance,was apparently related to inter-individual resource variation and promoted the emergence of significant modularity within all networks.The observed patterns of nestedness and modularity,together with the variation in resource diversity and intra-specific competition,are in agreement with the distinct preferences model of ODT.These findings suggest that in the focal prey–predator systems,individuals were able to perceive changes in prey diversity and to exploit in different ways the variations in composition of available resources,shifting their diet assembly rules accordingly.Our findings also confirm that the use of weighted individual-resource networks,in prey–predator systems,allows to disclose dynamics that are masked at the species or population level.展开更多
文摘Subterranean environments are buffered from external climatic fluctuations due to the absence of light and a delayed thermal response to surface conditions(Mammola 2019).Terrestrial salamanders are often found in subterranean habitats,but few studies have assessed the influence of climatic effects on their long-term spatial distribution and niche breadth.In this study,we investigated the variability over 29 consecutive years of the spatial niche in a terrestrial salamander population inhabiting an artificial subterranean habitat.We hypothesized that juvenile salamanders,which are typically active near cave entrances and more exposed to climatic variability and dehydration(Peterman et al.2013),would exhibit an earlier and more variable behavioral adaptation to increasing external temperatures compared to adults.
基金by the Italian Ministry of Environment(DPN–2008–0008213 and PNM–II–2012–0015691)by the Prefecture of Haute Corse,France(2B–2018–01–92–004).
文摘Ecological networks,usually depicting interactions among species,have been recently down-scaled to the individual level,permitting description of patterns of inter-individual resource variation that are usually hindered at the species level.Optimal diet theory(ODT)models,applied to prey–predator systems,predict different patterns of nestedness and modularity in the network,depending on the available resources and intra-specific competition.The effect of resource availability on the emergence of networks structures,and ODT framework,has not yet fully been clarified.Here,we analyzed the structural patterns of individual-resource networks in 3 species of Mediterranean salamanders,in relation to changes in prey availability.We used weighted individual-resource network metrics to interpret the observed patterns,according to 3 ODT models.We found significant nestedness recurring in our study system,indicating that both selective and opportunistic individuals occur in the same population.Prey diversity,rather than abundance,was apparently related to inter-individual resource variation and promoted the emergence of significant modularity within all networks.The observed patterns of nestedness and modularity,together with the variation in resource diversity and intra-specific competition,are in agreement with the distinct preferences model of ODT.These findings suggest that in the focal prey–predator systems,individuals were able to perceive changes in prey diversity and to exploit in different ways the variations in composition of available resources,shifting their diet assembly rules accordingly.Our findings also confirm that the use of weighted individual-resource networks,in prey–predator systems,allows to disclose dynamics that are masked at the species or population level.
