Evaluating hypotheses about dispersal in a vulnerable butterfly

Abstract

Sound management of species requires reliable estimates of dispersal. Indeed, dispersal of individuals among local populations is a key factor in the biology and persistence of local populations and metapopulations. Here, the small-scale dispersal pattern of a vulnerable species, the endemic Sardinian chalk hill blue butterfly, was studied by applying capture-recapture multistate models and a model selection based on AIC values. Model parameters were survival, capture and movement probabilities. The model selection showed that (a) survival probability of individuals varied between sexes, (b) capture probability varied between sexes and among patches, and (c) movement probability varied with direction. The probability of movement among adjacent local populations was generally low and ranged from 0.009 to 0.212. Movement probabilities were subsequently modeled using data on interpatch distance and donor patch population size or area. The ultrastructural ''biology-based'' models turned out to be the most appropriate models for inference, showing that dispersal decreases with increasing interpatch distance and increasing donor patch population size or area, and suggesting that butterfly dispersal is affected by patch geometry and the presence of conspecifics. The application of multistate models, the model selection approach, and ultrastructural modeling allowed testing the validity of some general hypotheses related to dispersal in metapopulations and helped elucidate the butterfly small-scale dispersal pattern.

Mobility of ringlet butterflies in high-elevation alpine grassland: effects of habitat barriers, resources and age

“…Since butterflies are model organisms for the study of dispersal, numerous studies on the mobility of butterflies already exist (e.g. Casula 2006;Hanski et al 2006;Nève et al 1996). However, while species of the genus Erebia make up an essential fraction of butterfly communities in alpine grassland habitats (Sonderegger 2005;Neumayer et al 2005;Gutiérrez 1997) still little is known about their dispersal behavior.…”

Towards a measure of functional connectivity: local synchrony matches small scale movements in a woodland edge butterfly

“…The importance of population connectivity for the persistence and conservation of metapopulations is widely recognised (Hanski and Gilpin, 1997;Roland et al, 2000;Moilanen and Hanski, 2001; 50 Casula, 2006). The more well-connected the populations are, the greater the opportunity for dispersal, colonisation and re-colonisation of habitat patches, thereby reducing the risk of extinction (Hanski, 1994;Hanski, 1999;Chardon et al, 2003).…”

Dispersal capability in a habitat specialist bush cricket: the role of population density and habitat moisture

“…Intensification, abandonment, and afforestation of semi-natural grassland habitats have resulted in the decline of many specialised insect species (van Swaay, 2002;WallisDeVries et al, 2002;Krauss et al, 2010). One major problem of this process is not only habitat loss, but also an increase in the degree of habitat fragmentation (Tscharntke et al, 2002;Fahrig, 2003;Ewers & Didham, 2006), because many insect species depend on regular exchange of individuals between subpopulations to ensure the persistence of the population (Hanski, 1998;Casula, 2006; Correspondence: Dominik Poniatowski, Department of Community Ecology, Institute of Landscape Ecology, University of Münster, Robert-Koch-Straße 28, 48149 Münster, Germany. E-mail: poni@ uni-muenster.de Polus et al, 2007).…”