Effects of habitat fragmentation on invertebrates

• Research unit: COST
• Project number: C99.0023

Key words (English)

Coleoptera; carabidae; habitat fragmentation; effective population size; geneflow; bottleneck

Research programs (English)

COST-Action 341 - Habitat fragmentation due to transportation infrastructure

Short description (English)

See abstract

Partners and International Organizations (English)

A, B, CY, CZ, DK, F, H, IRL, NL, N, P, RO, E, S, CH, GB

Abstract (English)

Although habitat fragmentation is suspected to threaten the long-term survival of many species, few data are available on its impact on the genetic structure and variability of invertebrates. We assessed the population genetic structure of the two flightless ground beetles Carabus violaceus and Abax parallelepipedus in a Swiss forest, which was divided into several fragments by a highway and two main roads. One to three samples were collected from each fragment and analysed at 5 - 13 microsatellite loci. In Carabus violaceus, the largest amount of genetic differentiation was observed between samples separated by roads and in particular the highway. The number of roads between sites explained 44% of the variance in pairwise FST-estimates, whereas the age of the roads and the geographical distance between locations were not significant factors. Furthermore, the genetic variability as measured by allelic richness was significantly reduced in a small forest fragment isolated by the highway. The impact of the roads on population structure was less pronounced in Abax parallelepipedus, and mainly detectable in the sample from the smallest forest fragment. These findings were consistent with the high abundance of the species observed in the field, as the speed of population divergence is directly dependent on the effective population size. Our results support the hypothesis that large roads can be strong barriers to dispersal for insects.

References in databases (English)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C99.0023