Effects of Long-Term Habitat Protection on Montane Small Mammals: Are Sorex araneus and S. minutus More Sensitive Than Previously Considered?

Protection of natural areas by restricting human activities aims to preserve plant and animal populations and whole communities, ensuring the conservation of biological diversity and enhancement of ecosystem services. Therefore, it is expected that the longer the protection, the stronger the desired effects. We evaluated the responses of small mammals at the population and community levels under protection in the southern Carpathian Mountains. We surveyed small mammals for five years in sites with long- and short-term protection and non-protected. Besides protection status, we included elevation, habitat heterogeneity, and the month of survey as predictors in our models. As response variables, we considered abundance, presence, species composition and species richness. Community abundance responded to all four predictors and species composition was influenced by protection status and month of study. The shrews Sorex araneus and S. minutus had positive responses to protection, both in terms of abundance and relative abundance (their ratio within the community). Our results suggest that overall, montane small mammal communities respond positively to long-term protection, especially S. araneus and S. minutus. These shrew species are considered habitat generalists, but they appear to be in fact sensitive to the habitat quality enhanced through protection.

Temporal and spatial changes in small mammal communities in a disturbed mountain forest

In 2005–2016, we investigated a secondary succession of small mammal communities in forest ecosystems in High Tatras (Slovakia) disturbed by windstorm and fire. This long-term ecological study confirmed the occurrence of significant temporal and spatial changes in species composition and number of dominant small mammal species. A comparison between disturbed and undisturbed plots indicated notable differences in species richness and abundance. The gradations of dominant small mammal species in disturbed habitats were asynchronous and showed a wider range of amplitude than in the undisturbed plots. An analysis of the temporal and spatial changes in the structure of small mammal communities in relation to selected environmental gradients confirmed the statistically significant effect of secondary succession on species composition, abundance, and exchange in forest ecosystems in the High Tatra Mountains following a disturbance.

Influence des perturbations anthropiques sur les communautés de petits mammifères des savanes gabonaises

Les savanes gabonaises connaissent des feux anthropiques récurrents, entraînant des dommages sur cet écosystème. L’influence de ce facteur sur la diversité des micromammifères n’a jamais été étudiée. Une situation préoccupante pour ce taxon qui fait l’objet de très peu de programmes de protection. A travers l’analyse de la distribution spatiale des espèces (Muridés), l’étude vise à mesurer l’empreinte écologique des activités anthropiques dans trois régions du Gabon, présentant des niveaux de perturbations différents. Au total 259 individus appartenant à six espèces de muridés ont été capturés avec un effort de 6220 nuit-pièges. Les rendements de capture varient de 0,5 à 15%. Mus minutoides (62,5%) et Lemniscomys striatus (28.9%) sont les plus abondantes. La richesse spécifique (S) varie de 1 à 4 espèces dans les savanes post -feu, alors qu’elle est de 5 dans les savanes protégées des feux, et de 2 espèces dans les savanes fauchées puis brulées. La diversité la plus élevée a été observée dans les savanes non exposées au feu (H’= 1,10 ; J= 0,68). Ceci atteste que le feu influe sur l’abondance, et lorsqu’il est préalablement associé à la fauche, il agirait à la fois sur la diversité et sur l’abondance d’espèces locales. English title: Influence of human disturbance to the small mammal communities in the Gabonese savannahs In the issue of the use of recurrent fires in Gabon, we carried out an inventory both in the Gabonese savannahs that are regularly burned and in those that are not. The study was carried out in the southern and central savannahs of Gabon during the periods from 2004, 2012 and 2013. A total of 259 individuals representing six species of small savannah rodents were captured over 6,220 trap nights. Trap success was variable (0.5 to 15%). Mus minutoides (62.5%) and Lemniscomys striatus (28.9%) are the most abundant. Small rodent abundance was significantly higher in the savannahs protected from fires. The species richness varies from 1 to 4 species in the post-fire savannahs and up to 5 species in the savannahs protected from fires. The savannahs that were mowing prior to burning have yielded only 2 species. The highest diversity index (H’) is found in savannahs not exposed to fire (H’= 1.10). Bush fires seem to have a direct effect on species abundance. Conversely, when savannahs are mown prior to burning, both the diversity and abundance of local species communities are affected. This study gave an initial idea of the diversity of the rodent population in this the recurrent use to fires.

Small mammals from barn owl Tyto alba pellets in a Mediterranean agroforestry landscape of central Italy

In order to investigate diversity patterns and similarities in the small mammal communities of an agroforestry landscape in western central Italy (Maremma of Lazio), we analyzed, in a multivariate setting (Cluster analysis, DCA-Detrended Correspondence Analysis), the prey content of barn owl Tyto alba pellets collected along one year in five sampling sites. Small mammal communities were composed by guilds typical of habitats included in agroforestry landscapes (croplands and mosaics, forests and ecotones, wet habitats and synanthropic ones). Since landscape matrices were characterized almost everywhere by croplands, typical agro-ecosystem species (Apodemus cfr. sylvaticus, Microtus savii, Mus domesticus and Soricidae) dominated in the majority of the collecting sites. The statistical analyses show how small changes in land use and cover can explain the faunal differences between sites, with the occasional presence of Arvicola italicus in wet habitats, and of Muscardinus avellanarius and Sorex samniticus in sites dominated by forest or agroforestry ecotones. Communities recorded in sites characterized by wet and forest habitats showed a higher distance from the others, dominated by croplands. Communities occurring in landscapes with the lowest habitat diversity showed also the lowest species diversity.

Small Mammals in Forests of Romania: Habitat Type Use and Additive Diversity Partitioning

Small mammals are key components of forest ecosystems, playing vital roles for numerous groups of forest organisms: they exert bottom-up and top-down regulatory effects on vertebrate and invertebrate populations, respectively; they are fungus- and seed-dispersers and bioturbators. Therefore, preserving or restoring the diversity of small mammal communities may help maintain the functions of these ecosystems. In Romania, a country with low-intensity forest management and a high percentage of natural forests compared to other European countries, an overview of forest small mammal diversity and habitat type use is lacking, and our study aimed to fill this gap. We also aimed to partition the total small mammal diversity of Romanian forests into the alpha (plot-level), beta, and delta (among forest types) diversities, as well as further partition beta diversity into its spatial (among plots) and temporal (among years) components. We surveyed small mammals by live trapping in eight types of forest across Romania. We found that small mammal abundance was significantly higher in lowland than in mountain forests, but species richness was similar, being associated with the diversity of tree canopy, with the highest values in mixed forests. In contrast, small mammal heterogeneity was related to overall habitat heterogeneity. As predicted, community composition was most distinct in poplar plantations, where forest specialists coexist with open habitat species. Most of the diversity was represented by alpha diversity. Because of strong fluctuations in population density of dominant rodents, the temporal component of beta heterogeneity was larger than the spatial component, but species richness also presented an important temporal turnover. Our results show the importance of the time dimension in the design of the surveys aiming at estimating the diversity of small mammal communities, both at the local and regional scales.

Spatial variation of small mammal communities in northwestern Argentina

Northwestern Argentina (NWA) is a region characterized by a complex geomorphology, and encompasses six ecoregions in a relatively small area. The environmental heterogeneity of NWA and the sensitivity of small mammals towards environmental and landscape changes constitute a good scenario to assess the factors that influence small mammal diversity patterns in the region. We studied small mammal communities obtained from pellet samples in 24 localities of NWA. We identified 50 non-volant small mammal species and obtained topographic, climate and land cover variables. Our results show that small mammal communities respond to environmental factors at a regional scale. Such variations were explained in different proportions by the geographic position of the collecting sites, landscape and climate. Furthermore, the combined effect of these factors was the main determinant of species abundance patterns. Our results support the need of large-scale approaches to study communities, since the explanations of the observed patterns are simpler and more general. We emphasize the importance of considering the combined effect of different environmental predictors, which allows determining the amount of species variation that is spatially structured, and within that, the amount of variation related to the influence of the measured environmental variables.