31 research outputs found
Mandible descriptors and PCs for comparison
Sheet 1: Mandible area and Fourier coefficients from A0 to B7 describing size and shape of the mandible. Sheet 2: Mechanical advantages (MAs) and axes for comparisons: PCclimate, PC for D-loop analysis, and PC for mitochondrial analysis
A Viable Population of the European Red Squirrel in an Urban Park
<div><p>Whether urban parks can maintain viable and self-sustaining populations over the long term is questionable. In highly urbanized landscapes, urban parks could play a role in biodiversity conservation by providing habitat and resources to native species. However, populations inhabiting urban parks are usually small and isolated, leading to increased demographic stochasticity and genetic drift, with expected negative consequences on their viability. Here, we investigated a European red squirrel population located in an urban park close to Paris, France (Parc de Sceaux; 184 ha) to assess its viability. Using mitochondrial D-loop sequences and 13 microsatellite loci, we showed that the population presented high levels of genetic variation and no evidence of inbreeding. The size of the population was estimated at 100–120 individuals based on the comparison of two census techniques, Distance Sampling and Capture-Mark-Recapture. The estimated heterozygosity level and population size were integrated in a Population Viability Analysis to project the likelihood of the population's persistence over time. Results indicate that the red squirrel population of this urban park can be viable on the long term (i.e. 20 years) for a range of realistic demographic parameters (juvenile survival at least >40%) and immigration rates (at least one immigration event every two years). This study highlights that urban parks can be potential suitable refuges for the red squirrel, a locally threatened species across western European countries, provided that ecological corridors are maintained.</p></div
Results of simulations run for the population viability analysis of red squirrels population of the Parc de Sceaux.
<p>Results of simulations run for the population viability analysis of red squirrels population of the Parc de Sceaux.</p
Map of the Parc de Sceaux showing the distribution of line transects, traps, and woody areas suitable to red squirrels.
<p>Map of the Parc de Sceaux showing the distribution of line transects, traps, and woody areas suitable to red squirrels.</p
Results of the genetic diversity analyses obtained per locus for the red squirrel populations.
<p>Results of the genetic diversity analyses obtained per locus for the red squirrel populations.</p
Relationships between the deterministic growth rate of the population, the rate of juvenile survival and the age at which females have their first litter.
<p>Relationships between the deterministic growth rate of the population, the rate of juvenile survival and the age at which females have their first litter.</p
Variation of <i>S. robustus</i> abundance by host body mass.
<p>Relationship between <i>S. robustus</i> abundance and host body mass: observed values (blank circles) and values predicted by the model at different host densities (lines). Host body mass had a positive effect on <i>S. robustus</i> abundance (p = 0.0005; parameter estimate: 0.0059±0.0017 SE).</p
Helminth species infecting grey squirrels in Piedmont and Lombardy populations.
<p>N: number of host examined; n: number of infected hosts; p: prevalence; mI: mean intensity (no. parasites infected/hosts; when number of infected hosts <5, worm counts in italic).</p
Minimum selected model of the effects of host characteristics and environmental variables on parasite abundance (no. of parasites/host).
<p>Minimum selected model of the effects of host characteristics and environmental variables on parasite abundance (no. of parasites/host).</p
Most prevalent gastro-intestinal helminths and arthropods (excluding mites) parasitizing grey squirrels in North America.
<p>Only parasites that were recorded by more than one author and with maximum prevalence >5% are reported. Studies with sample size <50 hosts were excluded.</p