Species‐specific responses to landscape fragmentation: implications for management strategies

Abstract

Habitat fragmentation affects the integrity of many species, but little is known about species-specific sensitivity to fragmentation. Here, we compared the genetic structure of four freshwater fish species differing in their body size (Leuciscus cephalus; Leuciscus leuciscus; Gobio gobio and Phoxinus phoxinus) between a fragmented and a continuous landscape. We tested if, overall, fragmentation affected the genetic structure of these fish species, and if these species differed in their sensitivity to fragmentation. Fragmentation negatively affected the genetic structure of these species. Indeed, irrespective of the species identity, allelic richness and heterozygosity were lower, and population divergence was higher in the fragmented than in the continuous landscape. This response to fragmentation was highly species-specific, with the smallest fish species (P. phoxinus) being slightly affected by fragmentation. On the contrary, fish species of intermediate body size (L. leuciscus and G. gobio) were highly affected, whereas the largest fish species (L. cephalus) was intermediately affected by fragmentation. We discuss the relative role of dispersal ability and effective population size on the responses to fragmentation we report here. The weirs studied here are of considerable historical importance. We therefore conclude that restoration programmes will need to consider both this societal context and the biological characteristics of the species sharing this ecosystem.

Hidden dispersal in an urban world: genetic analysis reveals occasional long-distance dispersal and limited spatial substructure among Dutch pine martens

“…This surprising conclusion gives hope for the survival of pine martens and related mustelids in our human-dominated world, although ongoing urbanization may already have started to impact gene flow at a yet still undetectable level and may impact genetic diversity in the future. Besides, our results reinforce the statement of Blanchet et al (2009) that the effects of habitat fragmentation may strongly differ between (groups of) species, and should therefore be assessed separately for organisms with different life histories. While any potential negative impact of infrastructural works on wildlife connectivity is best avoided, detailed and landscape-scale information on multiple species would strongly aid managers to prioritize and optimize measures to mitigate the effects of fragmentation.…”

“…Yet, responses are variable among groups of species (Blanchet et al 2009). Many carnivorous mammals are disproportionately affected by habitat destruction, as they typically occur in low densities and thus require large areas to sustain a genetically viable population (Henle et al 2004).…”

The impact of wildfire on stream fishes in an Atlantic-Mediterranean climate: evidence from an 18-year chronosequence

“…KAM). Despite their small-scale, such structures can fragment river ecosystems and impede dispersal, leaving fish populations vulnerable to subsequent disturbance (Blanchet et al, 2010). While the analysis of fish presence verses barriers was not statistically significant, this result may, in part, be explained by the absence of fish at several burnt sites without barriers where naturally steep channel slopes may have otherwise restricted colonization.…”

Heritable variation in host tolerance and resistance inferred from a wild host–parasite system

“…Host sampling was conducted by electric-fishing according to French legislation and prefectoral decrees from the Direction Départementale des Territoires at eight sampling sites which cover the whole distribution of dace in the river (see the electronic supplementary material, figure S1). We consider individuals from these sampling sites to belong to the same population, because we previously showed that genetic spatial structure in this river was weak (with a mean pairwise F ST ¼ 3.06% [30]). These eight sampling sites have been monitored at the end of June for each year from 2005 to 2011.…”