High expression of canines in some Mediterranean roe deer populations against the general evolutionary trend

Upper canines do not usually appear in the roe deer Capreolus capreolus, Linnaeus 1758 and their occasional appearance represents the expression of a tooth, as a rudimentary canine, which has been suppressed in the evolution of the group. These dental anomalies could be potentially useful for tracing ancestral genes in local ecotypes and populations. We studied the skulls of 517 adult roe deer males from seven Iberian Peninsula hunting populations looking for canine occurrence and the variations depending on region and ecomorphological variety. A total of 18 specimens had canines (3.48 %) but a relationship was detected between the geographic origin and the canine presence. We found upper canines in three populations which were those located in the Tagus river basin, with 6.08 %, 10.91 % and 20 % prevalences, respectively. In the population with the highest prevalence, we also found a case of duplicated canines on either side of the upper jaw. Here, the high prevalence of upper canines against the evolutionary trend may be a sign of atavistic populations, possibly adapted to a less fibrous diet, in a geographical area connected through the Tagus river basin, and probably regarding one of the glacial refuges of the Iberian Peninsula.

The effect of livestock on the physiological condition of roe deer (Capreolus capreolus) is modulated by habitat quality

Free-range livestock grazing is a widespread human activity that not only modifies natural vegetation but also leads to interactions with wild ungulates. Most commonly, the interactions between cattle and wild ungulates have been studied with a focus on competition for high-quality forage. However, other mechanisms, such as the risk of parasite infection, might better describe this interaction. We aim to determine whether livestock affect roe deer (Capreolus capreolus Linnaeus, 1758) by reducing habitat quality and increasing the probability of infection by shared parasites. We measured noninvasive fecal cortisol metabolites as an indicator of habitat quality as well as the lung nematode larvae burden from the Dictyocaulus genus. A higher Dictyocaulus larvae load was found in the presence of livestock in pines, and feces collected in winter had a higher parasite load than feces collected in autumn. Additionally, fecal cortisol metabolite levels in the roe deer were affected by the interaction between habitat quality and livestock presence and were higher in the poorest habitat and when living in sympatry with cattle. Our results suggest that physiological stress responses in roe deer were mediated by the habitat type and the presence of competitors. The long-term implications of altered physiological responses such as those demonstrated here should be considered in management strategies for deer.

Linking species functional traits of terrestrial vertebrates and environmental filters: A case study in temperate mountain systems

Knowledge on the relationships between species functional traits and environmental filters is key to understanding the mechanisms underlying the current patterns of biodiversity loss from a multi-taxa perspective. The aim of this study was to identify the main environmental factors driving the functional structure of a terrestrial vertebrate community (mammals, breeding birds, reptiles and amphibians) in a temperate mountain system (the Cantabrian Mountains; NW Spain). Based on the Spanish Inventory of Terrestrial Vertebrate Species, we selected three functional traits (feeding guild, habitat use type and daily activity) and defined, for each trait, a set of functional groups considering vertebrate species with common functional characteristics. The community functional structure was evaluated by means of two functional indexes indicative of functional redundancy (species richness within each functional group) and functional diversity. Ordinary least squares regression and conditional autoregressive models were applied to determine the response of community functional structure to environmental filters (climate, topography, land cover, physiological state of vegetation, landscape heterogeneity and human influence). The results revealed that both functional redundancy and diversity of terrestrial vertebrates were non-randomly distributed across space; rather, they were driven by environmental filters. Climate, topography and human influence were the best predictors of community functional structure. The influence of land cover, physiological state of vegetation and landscape heterogeneity varied among functional groups. The results of this study are useful to identify the general assembly rules of species functional traits and to illustrate the importance of environmental filters in determining functional structure of terrestrial vertebrate communities in mountain systems.

Habitat use by sympatric red and roe deer in a Mediterranean ecosystem

Much recent research has focused on understanding the environmental factors that limit the distribution and abundance of species. However, by no means all models consider the effects of interspecific competition on species’ distributions. In this study, we explore the contribution of both environmental factors and the presence of another ungulate species on the distribution of two sympatric deer species: roe deer (Capreolus capreolus) and red deer (Cervus elaphus). To assess the importance of both biotic and abiotic factors, we constructed models for each species incorporating environmental predictors and an index of abundance of the other species. High density of shrubs and distance to roads had a positive affect on roe deer occurrence while spatial heterogeneity, namely mean shape index, and the presence of red deer had a negative effect. In contrast, the percentage of shrub cover, landscape heterogeneity and the presence of roe deer all positively affected red deer occurrence. Our results suggest that interspecific competition between these species might occur with asymmetric effects and underlines the need to explore the nature of these interactions in greater detail in southern ecosystems.

Water requirements as a bottleneck in the reintroduction of European roe deer to the southern edge of its range

Success rates of reintroduction programs are low, often owing to a lack of knowledge of site-specific ecological requirements. A reintroduction program of European roe deer ( Capreolus capreolus (L., 1758)) in a dry Mediterranean region in Israel provides an opportunity to study the bottleneck effect of water requirements on a mesic-adapted species. Four does were hand-reared and released in a 10 ha site consisting of an early succession scrubland and a mature oak forest. We measured daily energy expenditure (DEE) and water turnover (WTO) using the doubly labeled water technique during summer and winter. DEE was similar in the summer and winter, but there was a significant difference in WTO and in the source of gained water. In winter, WTO was 3.3 L/day, of which 67% was obtained from vegetation. In summer, WTO dropped to 2.1 L/day, of which only 20% was obtained from the diet and 76% was gained from drinking. When the water source was moved to a nonpreferred habitat, drinking frequency dropped significantly, but water consumption remained constant. In a dry Mediterranean environment, availability of free water is both a physiological contraint and a behavioral constraint for roe deer. This study demonstrates the importance of physiological and behavioral feasibility studies for reintroduction programs.