PARENT SESSION
Organized Oral Session 2: Measuring landscape connectivity - tool for species conservation
Organizer(s): P Kindlmann, F Burel, and J Baudry
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 510b, Level 5, Palais des congrès de Montréal

Behavioural aspects of landscape connectivity: Perceptual range, grain of the landscape and special dispersal movements in the bog fritillary butterfly Proclossiana eunomia.

Baguette, Michel^*,1, Schtickzelle, Nicolas, Van Dyck, Hans¹, ¹ Catholic University Louvain (UCL), Biodiversity Research Centre, Ecology & Biogeography unit, Louvain-la-Neuve, Belgium

ABSTRACT- Dispersal bears a cost for the individual. Theory predicts, and some empirical studies documents, a higher dispersal mortality in the matrix associated to habitat fragmentation due to predation risk and the uncertainty to reach another suitable habitat patch. Even if the dispersing individual makes its way to some suitable habitat, it has lost time during travel, which may affect realized fitness. We may predict that behavioural responses have evolved to limit this cost. Besides refusal behaviour at habitat patch boundaries, changes in behaviour during travelling in the matrix could be another adaptive answer to lower dispersal cost: individuals should try to limit the time spent travelling in the matrix and to maximise the probability to end up in another suitable habitat. Under metapopulation conditions, in fragmented landscapes when the cost of dispersal is often not negligible, we predict a change in the pattern of movements for travelling in the matrix compared to movements in the habitat. Here we test this prediction by quantifying the movement behaviour of the butterfly Proclossiana eunomia in and outside habitat in two different landscapes differing in degree of fragmentation. Perceptual range was only between 15 and 30 m. Butterfly movements were significantly influenced by the suitability of their environment: butterflies showed more linear flight behaviour in the matrix than within the habitat (longer moves, smaller turns, larger area explored). Our results support the view that between-patch dispersal in fragmented landscapes (where the grain of the resource is larger than the perceptual range of the organism) is rather realized by special, directed movements than being a by-product of routine, explorative movements as shown within habitat.

Key words: Functional connectivity, Cost of dispersal, Dispersal mortality, Metapopulation