Most studies focused on species coexistence have been directed at the differential use of habitat and food resources; nonetheless, the differential use of the diel cycle may enhance the coexistence of same-sized species. We investigated the activity patterns of mesocarnivores (red fox (Vulpes vulpes), European badger (Meles meles), pine marten (Martes martes), stone marten (M. foina)) in NW Italy via camera-trapping. We hypothesized that the smallest species would tend to avoid competition by selecting time periods when larger species were less active. Foxes, badgers, and stone martens were mainly nocturnal. In lowland areas overlap between coexisting species was generally low, while in Mediterranean habitats all activity patterns tended to be unimodal and overlap was generally high. The pine marten showed a cathemeral pattern. We suggest that the lower ability of the stone marten to avoid interference competition at community-level may play a major role in determining its widespread exclusion from forested areas by the pine marten.
1 October 2020 in Science of The Total Environment
Long-term population trends are considerable sources of information to set wildlife conservation priorities and to evaluate the performance of management actions. In addition, trends observed in functional groups (e.g., trophic guilds) can provide the foundation to test specific hypotheses about the drivers of the observed population dynamics. The aims of this study were to assess population trends of breeding birds in Lombardy (N Italy) from 1992 to 2019 and to explore the relationships between trends and species sharing similar ecological and life history traits. Trends were quantified and tested for significance by weighted linear regression models and using yearly population indices (median and 95% confidence interval) predicted through generalized additive models. Results showed that 45% of the species increased, 24% decreased, and 31% showed non-significant trends. Life history traits analyses revealed a general decrease of migrants, of species with short incubation period and of species with high annual fecundity. Ecological traits analyses showed that plant-eaters and species feeding on invertebrates, farmland birds, and ground-nesters declined, while woodland birds increased. Further studies should focus on investigation of the relationship between long-term trends and species traits at large spatial scales, and on quantifying the effects of specific drivers across multiple functional groups.
Integrating host plants in distribution modeling of phytophagous species and disentangling the effect of habitat and bioclimatic variables are key aspects to produce reliable predictions when the aim is to identify suitable areas outside species’ native range. To this aim, we implemented a framework of Species Distribution Model aimed at predicting potential suitable areas of establishment for the beetle Psacothea hilaris across the world. Since habitat (including host plants) and bioclimatic variables affect species distribution according to processes acting at different geographical scales, we modeled these variables separately. For the species native range, we fitted a habitat (HSM) and a bioclimatic (BSM) suitability model calibrated on a local and a large scale, respectively; the overall suitability map was obtained as the spatial product of HSM and BSM projection maps. ROC, TSS and Cohen’s Kappa obtained in validation confirmed a good predictive performance of modeling framework. Within HSM, host plants played a substantial effect on species presence probability, while among bioclimatic variables, precipitation of the warmer quarter and isothermality were the most important. Native HSM and BSM models were used to realize an overall suitability map at world scale. At global scale, many areas resulted suitable for habitat, some for bioclimate, and few for both conditions; indeed, if the species would not be able to modify its bioclimatic niche, it might not be considered a major invasive species. However, the high rate of range expansion documented for P. hilaris in Northern Italy, a poorly suitable bioclimatic area, suggests a plasticity of the species that requires increasing the level of attention to its invasive potential.