José María Gil-Sánchez

Ecology of the native and introduced crayfishes Austropotamobius pallipes and Procambarus clarkii in southern Spain and implications for conservation of the native species

The former and present distribution of white clawed crayfish (Austropotamobius pallipes) in the province of Granada (southern Spain) is studied. Before 1980 it was widely distributed but at present only 16 populations exist. The decline is related to the presence of the freshwater red-swamp crayfish (Procambarus clarkii), an American species, vector of the aphanomycosis disease, introduced to the Iberian Peninsula in 1974 and now widely distributed in the watercourses and marshes of southern Spain. To establish an appropriate conservation policy for A. pallipes at its southernmost distribution limit, we studied watercourses from two river basins, Genil and Guadiana Menor, (tributaries of the Guadalquivir River). P. clarkii inhabits the medium to lower reaches of these two river basins (with its upper limit at 820 m a.s.l.). The distribution of this species was best explained by the effect of three of the 12 analyzed variables: altitude, water-current and minimum winter temperatures. From our results, the repopulation of the native crayfish is almost impossible in those reaches inhabited by P. clarkii. However, based on the habitat selection study, it is clear that upper reaches are unsuitable for the red-swamp crayfish, where the native white-clawed crayfish may have greater survival possibilities, and these sites can be used for future restocking projects.

Badger Meles meles feeding ecology in dry Mediterranean environments of the southwest edge of its distribution range

The dietary preference of badgers Meles meles (Linnaeus, 1758) for earthworms and other food resources has been widely discussed. In the Mediterranean area, rabbits Oryctolagus cuniculus, fruits (mainly olives Olea europaea) and arthropods are the most important foods. We describe badger dietary habits in a xeric Mediterranean area, comparing use and availability of olives and rabbits. Our results indicated that olives and rabbits are the predominant resources consumed, however we did not detect any evidence of specialisation when we compared consumption versus field availability. In the case of olives we found that their consumption is reduced when juvenile rabbits or figs Ficus carica are widely available, which is evidence against any specialisation in this resource. Figs appear to be a key food item for badgers; they were consumed in large amounts when available. Badgers in this xeric area can be viewed as generalist or facultative specialists, using the most profitable resource when available but shifting its preferences to other less profitable food resources when availability of other primary food resource are reduced. Our results also indicated the high suitability of some human agricultural uses (eg fruit orchards) for this species, especially in the otherwise harsh Mediterranean environments.

How accurate are coat traits for discriminating wild and hybrid forms of Felis silvestris

Abstract Hybridisation between domestic cats, Felis catus, and wildcats, Felis silvestris, could lead to the genetic extinction of the latter; therefore, checking hybridisation rates in wild populations is of vital conservation importance. However, detecting hybridisation in the field is particularly challenging. Here, we aim to test the success of morphological-based procedures for discriminating wildcats from their hybrids and domestic cats, against genetic methods. We checked 17 putative Spanish wildcats by using two different classification systems based on coat patterns. None of the putative wildcats analysed in this study seemed to have an admixed genotype. Concordance between genetic and pelage approaches was almost total: only one coat classification produced mixed results with detection of one potential hybrid. Assignment was worse when performed in the field after a rapid examination of coat characters. We conclude that classification systems using coat traits could serve as surrogates of genetic approaches, but only after careful examination of those characters with more discriminatory power. Thus, the control of hybrid populations in the field as a management tool to preserve the genetic identity of wild forms is problematic if based on crude approaches or incomplete classification systems.

Females know better: Sex‐biased habitat selection by the European wildcat

Abstract The interactions between animals and their environment vary across species, regions, but also with gender. Sex‐specific relations between individuals and the ecosystem may entail different behavioral choices and be expressed through different patterns of habitat use. Regardless, only rarely sex‐specific traits are addressed in ecological modeling approaches. The European wildcat (Felis silvestris silvestris) is a species of conservation concern in Europe, with a highly fragmented and declining distribution across most of its range. We assessed sex‐specific habitat selection patterns for the European wildcat, at the landscape and home range levels, across its Iberian biogeographic distribution using a multipopulation approach. We developed resource selection functions in a use‐availability framework using radio‐telemetry data from five wildcat populations. At the landscape level, we observed that, while both genders preferentially established home ranges in areas close to broadleaf forests and far from humanized areas, females selected mid‐range elevation areas with some topographic complexity, whereas males used lowland areas. At the home range level, both females and males selected areas dominated by scrublands or broadleaf forests, but habitat features were less important at this level. The strength of association to habitat features was higher for females at both spatial levels, suggesting a tendency to select habitats with higher quality that can grant them enhanced access to shelter and feeding resources. Based on our results, we hypothesize that sex‐biased behavioral patterns may contribute to the resilience of wildcats’ genetic integrity through influencing the directionality of hybridization with domestic cats. Our study provides information about European wildcats’ habitat use in an Iberian context, relevant for the implementation of conservation plans, and highlights the ecological relevance of considering sex‐related differences in environmental preferences.

Evaluating methods for surveying the Endangered Cuvier's gazelle Gazella cuvieri in arid landscapes

The Endangered Cuviers gazelle Gazella cuvieri is an endemic ungulate of north-western Africa. Information on the species has been based primarily on non-systematic surveys, and the corresponding status estimates are of unknown quality. We evaluate the effectiveness and efficiency of two field methods for systematic surveys of populations of Cuviers gazelle in arid environments: distance sampling (based on sightings) and sampling indirect sign (tracks and scats). The work was carried out in the north-western Sahara Desert, in Morocco, where what is possibly the largest population of Cuviers gazelle persists. A logistically viable survey was conducted over a total area of c. 20.000 km² in 10 expeditions during 2011–2014. A total of 67 sites were surveyed, with 194 walking surveys (2,169 km in total). Gazelle signs were detected at 50 sites, and gazelles were sighted at 21 sites (61 individuals). We found a relationship between sightings and abundance indices based on indirect sign, which could be useful for population monitoring or ecological studies. Additionally, the data could be used in occupancy modelling. Density estimates based on distance sampling required considerable effort; however, it is possible to survey large areas during relatively short campaigns, and this proved to be the most useful approach to obtain data on the demographic structure of the population.