The future of endangered crayfish in light of protected areas and habitat fragmentation

The long-term survival of a species requires, among other things, gene flow between populations. Approaches for the evaluation of fragmentation in the frame of freshwater habitats consider only a small amount of the information that combined demography and geography are currently able to provide. This study addresses two species of Austropotamobius crayfish in the light of population genetics, spatial ecology and protected areas of the Carpathians. Advancing the classical approaches, we defined ecological distances upon the rasterised river network as a surrogate of habitat resistance to migration, quantifying the deviations from the species´ suitability range for a set of relevant geospatial variables in each cell of the network. Molecular analyses revealed the populations of the two Austropotamobius crayfish species are clearly distinct, lacking hybridisation. Comparing pairs of populations, we found, in some cases, a strong disagreement regarding genetic and ecological distances, potentially due to human-mediated translocations or the geophysical phenomena of regressive erosion, which may have led to unexpected colonisation routes. Protected areas were found to offer appropriate local habitat conditions but failed to ensure connectivity. The methodology applied in this study allowed us to quantify the contribution of each geospatial (environmental) variable to the overall effect of fragmentation, and we found that water quality was the most important variable. A multilevel approach proved to reveal a better understanding of drivers behind the distribution patterns, which can lead to more adequate conservation measures.

Natural and anthropogenic substrates affect movement behavior of the Southern Graycheek Salamander (Plethodon metcalfi)

Movement behavior is a critical process that interacts with landscape structure to affect population connectivity and persistence in fragmented or altered landscapes. The purpose of our study was to test whether different substrates (forest litter, soil, grass, gravel, and asphalt) found in fragmented forested landscapes affected the movement behavior of the Southern Graycheek Salamander (Plethodon metcalfi Brimley, 1912). Latency period of the salamanders was highest on grass substrate and significantly lower only on soil substrate. Sinuosity of the movement path of salamanders was lowest and contained more turns in grass and was significantly higher than only gravel and asphalt substrates. Velocity of the salamanders was highest on asphalt substrate but was not different from gravel substrate. Velocity was higher on asphalt than on grass, forest, or soil, and velocity was higher on gravel than on grass substrate. The results indicated that P. metcalfi reacted differently to natural and anthropogenic substrates, and we suggest that these behavioral differences could have both positive and negative implications for movement success and habitat resistance in forested landscapes fragmented by roads and development.