Journal Article

Quantifying functional connectivity: experimental assessment of boundary permeability for the natterjack toad (Bufo calamita)

Stevens, Virginie M, Baguette, Michel, Leboulengé, Éric, Wesselingh, Renate A

2006

Overview

Like other pond-breeding amphibians, the natterjack toad (Bufo calamita) typically presents a patchy distribution. Because the species experiences high probabilities of local population extinction, its persistence within landscapes relies on both local and landscape-scale processes [dispersal allowing the (re)colonization of habitat patches]. However, the structure and composition of the matrix surrounding local populations can alter the dispersal rates between populations. As shown previously (Landscape Ecol 19:829-842, 2004), the locomotor performances of individuals at the dispersal stage depend on the nature of the component crossed: some landscape components offer high resistance to movement (high resistance or high viscosity components) whereas others allow high efficiency of movement (low resistance components). We now examine the ability of individuals to discriminate between landscape components and select low-resistance components. Our experimental study investigates the ways in which young natterjack toads choose from among landscape components common to southern Belgium. Toadlets (the dispersal stage) were experimentally confronted with boundaries between surrogates of sandy soils, roads, forests, agricultural fields and intensive pastures. Our results show: 1 the ability of toadlets to react to boundaries between landscape components, 2 differences in permeability among boundaries, and 3 our inability to predict correctly the permeability of the boundaries from the patch-specific resistance assessed previously. Toadlets showed a preference for bare environments and forests, whereas they avoided the use of agricultural environments. This pattern could not be explained in terms of patch-specific resistance only, and is discussed in terms of mortality risks and resource availability in the various landscape components, with particular attention to repercussions on conservation strategies.

• Publisher: Berlin/Heidelberg : Springer-Verlag,Springer,Springer Nature B.V
• Subject: Agricultural land / Amphibians / Animal and plant ecology / Animal, plant and microbial ecology / Animals / Belgium / Biological and medical sciences / Boundaries / Bufonidae / Bufonidae - physiology / Cements / Conservation biology / Conservation Ecology / Conservation of Natural Resources / Demography / Dispersal / dispersal behavior / Ecosystem / Environment / Forest habitats / Forest litter / forests / Fundamental and applied biological sciences. Psychology / General aspects / Grasses / Habitat conservation / habitat fragmentation / habitat preferences / Health risks / land use / Landscape / Landscapes / Linear Models / Local population / Locomotion / Locomotion - physiology / Metapopulation ecology / Mortality risk / Pasture / Permeability / physiology / Population Dynamics / Resource availability / Sandy soils / Species extinction / Studies / Toads