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Teeth root morphology and integrity are essential to provide appropriate attachment, allowing for continuous and functional movement, with implications for adequate food processing, animal performance, and longevity. We studied the occurrence of supernumerary roots in mandibular molariform teeth of red deer ( Cervus elaphus Linnaeus, 1758) from seven separate populations spanning a range of latitudes in the Iberian Peninsula. We analyzed the influence of several factors, including sex, origin (native vs. reintroduced), lineage, and habitat, to assess extra root prevalence variations. The highest prevalence in deciduous teeth was found in pm3 (14%) and in permanent teeth in M1 (3%). We found significant differences between areas, lineages, and soil type; however, no significant relationships were found with the origin or the sex of individuals. We speculate that the high prevalence of supernumerary roots in M1 might be related to increased wear in grazers. Furthermore, we suggest that this high prevalence in deciduous teeth might be associated with a hard diet, dry climatic conditions, and a harsh weaning period, which indicate that supernumerary roots might have an adaptive value.

Wild ungulates seek out food resources at the bottom of mountain valleys in winter and spring, where their high density can negatively impact the production of hay meadows. This study determines the factors that explain the meadow use of four sympatric species: red-, roe-, and fallow-deer, and wild boar. In 2017, we counted the individuals of each species in 94 meadows for eight nights, between March and June, and estimated the frequency of meadow use as the proportion of positive censuses over the total censuses per meadow. We also recorded the presence of domestic ungulates. We inventoried the floristic composition in June. Species tended to use different meadows but only fallow- and roe-deer significantly segregated, indicated by the negative C-score index. As the ungulate frequency was skewed to 0, we used a generalized additive model (GAMLSS) to simultaneously simulate the probability of animals being absent and the frequency of positive censuses. Landscape features contributed to explaining the absence probability, while plant richness and legume cover explained the frequency of meadow use. The presence of domestic ungulates did not affect wild ungulate behavior. All studied species, except roe-deer, avoided exposed spots, preferentially using large meadows close to the forest. At meadow level, each species seemed to have different forage requirements. The frequency of fallow deer increased with the meadow forage quality, indicating a more grasses-based diet than the other two deer, and probably displacing roe-deer to suboptimum meadows. Red-deer used less plant-rich meadows, suggesting flexibility in their dietary choices.

Viruses that affect lagomorphs have decades of reported history of spillover events. One of these viruses is the causative agent of the so-called rabbit or ‘lagomorph’ haemorrhagic disease (e.g. Lagovirus europaeus/GI.1 and L. europaeus/GI.2). In particular, L. europaeus/GI.2 has shown a great capacity to recombine with existing lagoviruses. In fact, it has replaced the former GI.1 genotype in the wild, and recently, an increase on spillover events has been detected among several lagomorph species including European and North American species of hares. In this study, we report for the first time the infection of a wild Iberian hare with GI.2 (RHDV2/b), potential shedding and associated histopathological alterations. We identify the recombinant GI.4P-GI.2 as causative of the infection and discuss plausible causes regarding the origin of the spillover event and its potential consequences for the Iberian hare wild populations, which is an endemic species of the Iberian Peninsula as well as an important game and prey species for many predators, including endangered species.

The common genet Genetta genetta is a carnivore of African origin introduced in Europe at least 13 centuries ago. Its distribution, located in the southwest of the continent, is chiefly constrained by climatic factors. With this premise, and taking into account the existing climate change projections, our goal was to assess possible changes in climatic suitability for common genet in Europe in the future. The maximum entropy statistical method was used to evaluate the potential effects of two greenhouse gas scenarios-low and high emissions-of an average ensemble of six different global circulation models. Projections showed that a large increase in climatically suitable habitat for common genet in continental Europe is likely in the next decades. In this way, the species range may expand within Europe to the east and north. The fact that the common genet may be favoured in a scenario of temperature increase is compatible with the origin of the species associated with hotter climates in Africa. However, despite these results, bioclimatic models do not represent the complete biotic and ecological niche of the species (e.g. competition, predation or dispersal ability), and a full understanding of potential future expansions should include factors that also determine the presence of the species at finer local scales. Bearing this in mind, we have to interpret our results as a first step towards the potential for species distribution change in the near future, but further work should incorporate environmental variability beyond climate in future projection assessments.

Este artículo contiene 7 páginas, 3 figuras., Predators are an important ecological and evolutionary force shaping prey population dynamics. Ecologists have extensively assessed the lethal effects of invasive predators on prey populations. However, the role of non-lethal effects, such as physiological stress or behavioural responses like dispersal, has been comparatively overlooked and their potential population effects remain obscure. Over the last 23 years, we developed a mark-recapture program for the Audouin’s gull and an intensive carnivore monitoring program to assess how the appearance and invasion of the study site by carnivores affects population dynamics. We evaluate changes in turnover of discrete breeding patches within the colony, age structure and breeding performance. Once carnivores entered the colony, the number of occupied patches increased, indicating a higher patch turnover. Breeders responded by moving to areas less accessible to carnivores. More importantly, the presence of carnivores caused differential (and density-independent) breeding dispersal: experienced, better-performing breeders were more likely to leave the colony than younger breeders. This differential dispersal modified the age structure and reduced the reproductive performance of the population. Our results confirm the importance experience in the study of populations. The role of differential dispersal for animal population dynamics might be more important than previously thought, especially under scenarios of global change., RESET (ref.CGL2017-85210-P), FPU (ref. FPU2012-000869), IBISES (ref. CGL2013-42203-R) and MINOW (ref. H2020- 634495). ASA and MG are supported by a postdoctoral contract co-funded by the Regional Government of the Balearic Islands and the European Social Fund (ref. PD/003/2016 and PD/023/2015).

The description of horn growth patterns is of utmost importance for the sustainable management of wild ungulate populations subjected to intense trophy hunting. This is a topic of renewed interest because horn growth patterns seem to be contingent on region and population. We sampled 2145 male Iberian ibexes (Capra pyrenaica) evenly distributed across the Els Ports de Tortosa i Beseit National Game Reserve, NE Spain. A total of 24,615 annual horn growth segments were measured and used to describe horn growth patterns of male ibexes and to test whether compensatory horn growth occurs in an heterogeneous area. We found that individual heterogeneity explained more than a quarter (27.75%) of the variability in annual segment length and that habitat characteristics foster significant phenotypic differences among male ibexes. Our results corroborate previous studies by demonstrating that compensatory horn growth in male ibexes, as in other members of the tribe Caprini, is inexistent. Our study goes one step further and suggests that compensatory horn growth in male ibexes is neither promoted by cohort effects nor by habitat differences. The absence of compensatory horn growth has important management implications, namely: (i) male ibexes are not able to recover from a bad start, and (ii) the species is prone to evolutionary effects from trophy hunting. We emphasize that the study of just one proxy of horn growth may hamper the current knowledge about compensatory mechanisms in wild ungulates and imperil the development of effective management measures.

Species distribution models (SDMs) have been widely tagged as valuable tools in a variety of conservation assessments to address pressing conservation problems. However, these solutions could be hampered by difficulties to overcome the knowledge-action boundary between conservation and modelling practice. These difficulties have been well typified in the ecological modelling sphere, but a specific conceptual framework on how to bridge this gap is still lacking. This work reports successful examples on how to use SDMs to identify the most favourable habitats for implementing conservation management actions. We use these examples to discuss about the three main topics that deserve special attention to help enhance information flow between practitioners and modellers: the decision context, the modelling framework and the spatial products. Finally, we suggest some practical solutions to improve applications of effective conservation action on the ground. We emphasize the importance of matching modelling goals and decision targets by a close collaboration of modellers with decision makers and species experts. Moreover, we highlight the key role of clear and useful spatial products to provide relevant and timely feedback to increase understanding and promote utilisation by conservation practitioners, and to inform and involve targeted audiences.

The objective of our study was to evaluate the hypothesis that the constraints on the expansion of the range of the common genet (Genetta genetta) in Europe are limitations derived from the species’ patterns of habitat selection. From a sample of 2073 genet occurrence data and using species distribution models (SDM) built with Maxent, our results show that temperature-related variables were the main factor explaining the current distribution of the species. The maximum winter temperature was by far the most important environmental constraint of the presence of the species, with genets showing a preference for higher temperatures in the two coldest seasons of the year. Genets appeared also associated to Mediterranean zones, preferred mid-elevations and were more often present in habitats dominated by sclerophyllous vegetation. Our results stongly support the view that the influence of temperature is a major limiting factor that impedes the spread of the genet northwards and eastwards into continental Europe and limits its distribution. Nevertheless, the current spread of its colonization fronts could lead to future changes in its distribution, so it would seem that its expansion has not yet finished.

The American mink (Neovison vison) is a semi-aquatic mustelid from North America that is considered an invasive species in many countries. Due to its reported damage to native species, efforts are often undertaken to eradicate or control these mink populations. The aims of this study were to describe the demographic structures of three mink populations subjected to different culling intensities, to detect possible variations in these structures caused by trapping and to identify possible efficient indicators of trapping efforts. From 1998 to 2011, a total of 1306 American mink collected during official culling operations in three different Spanish areas were submitted for study. We sexed the carcasses and removed a canine tooth from each animal during the post-mortem procedures. The incremental cementum lines of the teeth were used for age estimation. No evidence of age structure changes was detected in any population. The proportion of individuals in each sex and age class remained constant over time, suggesting that despite control efforts, the age structure remained stable over the study period. The population with the highest culling intensity has the highest sub-adult/adult ratio (1.51), and the catch per unit effort in this area was lower in the second part of the period, which is a possible indicator of reduced density. Age structure and sub-adult ratio might be useful indicators of successful trapping efforts. The results from this study could be useful for decision-making in conservation of native species and management of mink populations.

An understanding of population dynamics, especially in endangered species that present metapopulation structures, such Arvicola sapidus, is important to gain knowledge of the dispersal and patterns of both occupation and space use. Here, we use radio tracking to report for the first time the relationship of the southern water vole with the environment in a Mediterranean mountain riparian area and also the relationships between individuals. Along the Montsant River, the size of the home ranges, the average distance travelled daily, the population density and the habitat quality were contrasted. In the subsection with better quality habitat, both the home ranges and distances travelled were smaller than in the subsection with poorer quality habitat, whilst population density was higher in the subsection with better quality habitat. Interactions (static and dynamic) between individuals reflected low sociality, especially between members of different groups. Within a group, adult males did not interact, but interactions between male and female adults intensified during the reproductive period. The home ranges of individuals changed with the emergence of new available gaps and in response to reproduction needs. Tracking a dispersant young male showed a trajectory in stages and made obvious the high risk of predation during this period. Our results here, and previously, indicate the possible effect of habitat quality on space use and relationships between individuals, emphasising the importance of the quality and structure of habitat in the conservation of the southern water vole.

The European mink (Mustela lutreola) has undergone a dramatic decline and is one of the most endangered mammals in the world. The invasive American mink (Neovison vison) is considered the main factor for this decline. However, the American mink's introduction and the subsequent ecological concurrence of the two species cannot solely explain the decline or disappearance of the European mink. Aleutian mink disease virus (AMDV) is the main health problem in fur farming worldwide, causing varied clinical syndromes that depend on the viral strain and host factors. Infection with AMDV has been speculated to contribute to the decline of the European mink, but a detailed study has not been performed. To assess the potential effects of AMDV infection on the conservation of the European mink, we surveyed AMDV antibody in samples from 492 native European mink and 1,735 feral American mink collected over 16 yr. The antibody prevalence in European mink was 32%. There were no statistically significant differences in antibody prevalence between sexes, among years, or among weight classes. For recaptured European mink, incidence of seroconversion (negative to positive) was 0.46 cases per animal-year at risk. For positive animals, the incidence of conversion from positive to negative was 0.18 cases per animal-year at risk. In 1,735 feral American minks, the overall prevalence was 32.4% and varied among the six wild populations studied. Infection with AMDV appears to be endemic, distributed across the entire ranges of both species, and no effects on the population dynamics of either species were observed.

La utilización de individuos capturados en el medio natural como factor fundamental del éxito en las translocaciones de vertebrados Resulta fundamental que las translocaciones de vertebrados den buenos resultados para mejorar la eficacia y la eficiencia de las medidas de conservación, si bien a menudo es difícil de evaluar debido a que los resultados negativos (translocaciones fallidas) raramente se publican. Elaboramos encuestas y las remitimos a los jefes de los servicios de conservación de tres importantes regiones mediterráneas de España. La finalidad de nuestras encuestas era determinar el factor metodológico, que pudiera ponerse en práctica con facilidad, más influyente en el éxito de las translocaciones. Entre estos factores figuraban la procedencia de los individuos translocados (cautividad o medio natural) y el esfuerzo de translocación (tamaño del propágulo y duración del programa). Tras analizar 83 programas, correspondientes a 34 especies diferentes de vertebrados, por medio de modelos mixtos lineales generalizados, observamos que la procedencia era más importante para el éxito de la translocación que el esfuerzo, si bien no pudimos descartar que este último tuviera alguna influencia. La varianza en el éxito de los programas de translocación que utilizan individuos procedentes del medio natural fue inferior y, en consecuencia, los resultados, más predecibles. La procedencia interaccionó con los taxones de forma que el éxito fue mayor cuando se utilizaron aves silvestres y, en especial, peces y mamíferos silvestres, pero no sucedió lo mismo cuando se liberaron reptiles. Por consiguiente, sugerimos que, para un esfuerzo dado, los resultados de la translocación serán mejores para la mayoría de taxones de vertebrados si se utilizan individuos procedentes del medio natural. Cuando esto no sea posible, los gestores deberían liberar durante muchos años individuos criados en cautividad., Success of vertebrate translocations is crucial to improve efficacy and efficiency of conservation actions but it is often difficult to assess because negative results (failed translocations) are seldom published. We developed surveys and sent them to heads of conservation services in three major Spanish Mediterranean regions. The purpose of our surveys was to determine which methodological factor, that could easily be implemented in practice, was more influential for translocation success. These factors included the origin of translocated individuals (captive or wild) and translocation effort (propagule size and program duration). After analyzing 83 programs, corresponding to 34 different vertebrate species, by means of generalized linear mixed modelling, we found that ‘origin’ was more relevant for translocation success than ‘effort’, although we could not rule out some role of translocation effort. Variance in success of translocation programs involving individuals from wild sources was smaller and consequently results more predictable. Origin interacted with taxa so that success was higher when using wild birds and especially wild fish and mammals, but not when releasing reptiles. Hence, we suggest that, for any given effort, translocation results will be better for most vertebrate taxa if individuals from wild sources are used. When this is not feasible, managers should release captive–reared individuals for a long number of years rather than a short number of years.

Resumen El conocimiento de las alternancias entre actividad/descanso durante ciclos de 24 h es importante para comprender la forma en que las especies interaccionan con el medio y, a la vez, puede proporcionar herramientas para desarrollar medidas de conservacion adecuadas. El conocimiento sobre esta alternancia de actividad y reposo es escaso en la rata de agua Arvicola sapidus, un roedor endemico de la peninsula Iberica y Francia. El presente estudio tiene como objetivo contribuir al conocimiento de los patrones de actividad/reposo hora a hora, mediante la cuantificacion de las distancias recorridas (asociadas a actividad) para diferentes individuos de Arvicola sapidus en un tramo del rio Montsant, utilizando la tecnica del radioseguimiento. Los resultados han mostrado que la rata de agua se comporta como una especie catemeral. La aproximacion al patron de actividad obtenida mediante datos sobre la frecuencia de actividad en intervalos de una hora mostro una menor resolucion que la aproximacion obtenida a partir de las distancias medias recorridas en intervalos de una hora. Los individuos que ocupaban un habitat suboptimo recorrieron una distancia media por hora mayor que la de los individuos que ocupaban un habitat optimo. La actividad se ha relacionado con las condiciones de habitat. Estas consideraciones ayudarian a explicar por que la fragmentacion y destruccion del habitat se configuran como las principales causas de regresion de la rata de agua, asi como la importancia de la conservacion del habitat para favorecer el mantenimiento de la especie. Palabras-clave: actividad, Arvicola sapidus, distancias recorridas, habitat, radioseguimiento. Abstract Knowledge of the alternation between activity and rest during the 24 h daily cycle is important in order to understand how species interact with the environment and can also provide tools for designing appropriate conservation measures. At present, little is known about this alternation in Arvicola sapidus, an endemic rodent restricted to the Iberian Peninsula and France. This study aims to extend our knowledge of this rodent’s hour to hour activity/rest patterns by using radiotelemetry to quantify the distances travelled (associated with activity) by individual southern water voles along a stretch of the Montsant River. The results showed that the southern water vole’s behaviour is cathemeral. The use of data of frequency of activity in one-hour intervals to assess the activity pattern showed a lower resolution than the use of data of the mean distances travelled in one-hour intervals. The individuals occupying a suboptimal habitat travelled a greater mean distance per hour than individuals occupying an optimal habitat, indicating that their activity was related to the habitat conditions. These considerations may help to explain why fragmentation and habitat destruction are emerging as the main cause of the decline of the southern water vole, and underline the importance of habitat conservation to encourage the maintenance of the species. Key words: activity, Arvicola sapidus, distances travelled, habitat, radiotelemetry. DOI: 10.7325/Galemys.2015.A5

Age estimation of three mustelid species with similar body size was performed in Northern Spain. Canine samples of 1766 carcasses from 1661 American mink (Neovison vison), 54 European mink (Mustela lutreola), and 51 European polecats (Mustela putorius) were sectioned, and cementum annuli counts in tooth sections were used for age estimation. American mink samples consisted primarily of trap-captured animals from governmental control campaigns, whereas road casualties were the principal origin of European mink and European polecat carcasses. Individuals prior to their first breeding season (class 0+) represented approximately half of all animals, with no significant differences between species or causes of death. Differences in sub-adult percentages were observed between the pre- and post-reproductive period, with a high mortality during the dispersal-winter period in all three species. Frequencies of mortality of the sub-adult age class were 0.46, 0.50, and 0.55 for American mink, European mink, and European polecat, respectively. Survival rates of the American mink were higher than those of the native species. The oldest animals detected were 7+, 5+, and 3+ years old for the American mink, European mink, and European polecat, respectively. No differences were observed in mean age of animals found dead as road casualties in all three species or between captured American mink and road casualties. The information obtained is of high value for understanding the demographic processes of the populations and particularly for conservation and management decisions for these species.

For the recovery and conservation of endangered species such as the southern water vole Arvicola sapidus, it is important to understand the effects of predation on their populations. The impact of a predator on a prey species depends on the dynamics and structure of their populations, the abundance of both species and their relationships with other species. When considering broad geographic areas, the analysis of the trophic dimension can provide an estimate of the effect of predatory pressure on the prey. To determine the potential impact of predators on the southern water vole, we used information provided in 74 studies concerning the diet of predators in the geographical range of the prey species. The trophic spectrum was determined based on faeces, stomach contents or pellets in which the arvicoline was present. Based on the percentage of biomass consumed in each of nine trophic categories, the potential impact posed by predators was linked with dietary profile, trophic diversity, intensity of southern water vole consumption and availability of preferred prey. In the localities studied, southern water voles are not the preferred prey of any of the predators we considered, but represent an alternative prey for some of them, especially when their main prey species are scarce. The predators with the greatest potential impact on southern water vole populations are Lutra lutra and Ardea cinerea; those with a moderate impact are some mesocarnivores (Felis silvestris, Genetta genetta, Neovison vison, Vulpes vulpes and Martes foina), a bird frequenting aquatic environments (Ciconia ciconia), and the raptors Aquila fasciatus and Hieraaetus pennatus. The results obtained may be useful in the planning of measures for the conservation of the southern water vole, such as translocations or reintroductions, and in the design of strategies to reduce predatory pressure with the aim of promoting the success of these programmes.

Predator control has historically shaped management towards minimising predator pressure on sensitive species in most hunting and protected areas. Despite widespread use, few studies of medium-sized carnivores have evaluated such control. To fill this void, we studied the effect of control on shaping a carnivore community consisting of European badgers Meles meles Linnaeus, 1758, stone martens Martes foina Erxleben, 1777 and red foxes Vulpes vulpes Linnaeus, 1758, in the Serra de Montsant area (NE Spain), and we report the recovery dynamics for different habitats (forest, scrubland and cultivated land) over time (3 years) when that control was halted. The results show that non-selective predator control is inadequate to reconcile the conservation of ecosystems with hunting. Specifically, it favours the frequency of occurrence of red foxes, which are the main consumer of small game species, and also reduces the frequency of occurrence of European badgers and stone martens, which are protected speci...

To promote management and conservation, it is useful to identify the factors that determine species distribution and to understand the mechanisms that regulate the organization of species assemblages or influence the dynamics of communities. Using information provided by 842 camera-trap photos and 8175 scats, we studied the factors that favour the coexistence of European badgers (Meles meles), red foxes (Vulpes vulpes) and stone martens (Martes foina) in a Mediterranean, agroforestry environment in the Iberian Peninsula. With extensive, simultaneous occupation of the space, and simultaneous activity during a broad time period (basically nocturnal and crepuscular activity patterns), the carnivores displayed different strategies depending on the availability of resources. In summer when plant resources were abundant and easy to access, there was a high overlap in patterns of diet and activity, and the temporal avoidance of the superior competitor allowed joint use of the same plots. In autumn, when there were fewer resources (although still sufficient) that were harder to access, the maintenance of food overlap was compensated for by avoidance and a reduction in overlapping activity. In winter and spring, the differentiation in response behaviour was evident in the partial substitution of plant resources. Differentiation in niche dimensions has been linked to complementarity, the differential needs and capacities of each species, and their biology. Differentiation in response behaviour was compatible with the hierarchical structure of the carnivores: European badger; red fox; stone marten. Knowledge of these factors and mechanisms increases our understanding and can help in the prediction of responses to disturbances. Consequently, it helps to improve management and conservation actions.

The Southern water vole, Arvicola sapidus, is endemic to the Iberian Peninsula and France. Despite being catalogued as vulnerable, our current knowledge of this species is not sufficient to establish measures for its conservation and recovery, particularly in riparian zones of Mediterranean mountain areas. The aim of this study was to identify factors related to habitat configuration that determine the presence or absence of the species in the Montsant River. Specifically, we associated the presence/absence of this arvicolid rodent with composition of vegetation, river bank morphology, and watercourse characteristics. The results suggest that, in this area, the most favorable places for the species are those with a high degree of cover of herbaceous plants (mainly helophytes) and moderate to low levels of tree and shrub cover; gently sloping banks and a soft substrate; and the presence of water, with moderate to high stream widths and depths. In addition, we developed a classification method which allowed us to classify and characterize habitat conditions: the optimal scenario (preferential for arvicoline establishment), the suboptimal scenario (whose use is related to opportunities to find best scenarios), and the hostile scenario (not acceptable for use). In such riparian areas, the results revealed that the Southern water vole is a specialist in terms of habitat selection, but behaves as a generalist in terms of occupancy. Its ability to adapt to suboptimal conditions widens the options for managing Southern water vole populations, and indicates that the maintenance and rehabilitation of habitat along continuous stretches of river is the most effective approach to achieving self-sustaining populations.

Loss of biodiversity due to biological invasions is one of the most critical issues our society is facing. American mink is one of the most nefarious invasive non-native species and has major consequences for diversity, ecosystems and economics. A project to evaluate the impact of American mink has been carried out in Catalonia since 2000 under the aegis of regional and national government and a European LIFE programme. In this study, we tested whether temporal variations in the relative abundance of native species were related to American mink. In addition, we compared the abundance of natives before and after mink arrival. Among the competitors spotted genet and European polecat, mink abundance and arrival had a significant negative effect on their populations. However, among black rat and fish prey only three native fish species had a negative temporal relation with the abundance of mink and three fish species showed a significant difference in their abundance before and after mink arrival. The effect of mink was significant among species with a higher niche overlap (polecat and genet versus mink). The persistence and coexistence of the alien and native species seems to depend on heterogeneity, in terms of the based on niche segregation among these species.

The traditional way to deal with hunting interests is often focused on predator control. This approach requires a detailed understanding of predator responses to game management. Control methods can be non-selective and, consequently, can potentially have a negative impact on non-target predator species, affecting carnivore guild. In order to assess the potential risks associated with non-selective predator control in the presence of intraguild competition, the classical Lotka–Volterra competition model was used, but with two additional factors: a linear factor for capture mortality (mortality caused by predator control) and a factor for vacated niche occupancy associated with immigration. Simulation in a scenario with three species revealed that one of them, the red fox Vulpes vulpes, which presented the highest intrinsic growth rate, can show population increases even under moderate control, whereas the population of European badger Meles meles, with a lower intrinsic growth rate, was reduced and, in some cases, may even become extinct. Lastly, the stone marten Martes foina presented a differential response, depending on the removal intensity and strategy employed. This behaviour is compatible with the results observed in a Mediterranean environment subjected to two types of game management: non-selective predator control (culling) and no control. In areas with non-selective control and moderate predator removal, the red fox population remained stable, while the stone marten and the European badger populations reduced markedly or disappeared.

Otters are elusive semi-aquatic mammals, occurring in low densities and difficult to count. A study was conducted in 15 stretches (10–12 km) of four tributaries of the Ebro River, with the aims to understand spatial and temporal changes in otter abundance and breeding success and the causes of such variations. Between 1990 and 2009, both otter parameters were assessed by means of visual spring–early summer censuses, carried out by sets of observers located every 500 m. A total of 134 censuses were carried out, involving 4,540 twilight watches (7,896.5 h) and 520 otter sightings were recorded. Also, 39 different habitat characteristics (including prey species) were established for each stretch. Otter abundance was assessed by means of three indexes related to the census effort and the length and surface units (in terms of otter habitat). Excluding the upper stretches, we found on average 0.07–0.26 adult and subadults per kilometre (1.45–6.26/km2). Important interannual fluctuations in otter abundance and breeding success were found in some Pyrenean stretches located downstream of a large reservoir. This was linked to the effect of autumn floods (in part due to the opening of dams) on the fish stocks (mainly Barbels). Similar habitat conditions resulted in similar abundances between stretches, and different habitat conditions generated different abundances in adjacent stretches of the same river. No significant differences were found for litter size between small cubs (1.60 ± 0.70 cubs per litter) and large cubs (1.39 ± 0.50) as a whole, but differences between stretches were found. On average we found between 0.009 and 0.130 large cubs per year per kilometre. Otters bred more successfully in stretches with higher otter densities. Otter abundance and breeding success correlated negatively with altitude as a consequence of the interaction of several habitat characteristics with altitude. The stepwise linear regression linked the number of adult otters per kilometre with the ecosystem production (chlorophyll a concentration), while the number of large cubs per kilometre per year was linked with the food (fish + crayfish) abundance. The findings bring about a consistent and congruent scenario of otter abundance and breeding success explained by the different steps along the food chain.

A study on Eurasian otter was conducted in order to establish if feeding ecology and breeding of this European freshwater top predator were affected by the habitat complexity or stability. The work was based on the comparison of contrasting environmental settings. Significant gradients were found for otter diet parameters and breeding, both also changing according to habitat gradient patterns (water capacity and permanence during droughts, habitat stability, and habitat complexity). The otter diet was less diverse in the most stable (and complex) habitats, eating more fish. Otters also breed more regularly in such more stable courses, with more suitable fish availability. The step toward lower habitat stability can put otters in a less advantageous position in front of generalist predators, foraging more frequently outside or in the edge of aquatic ecosystems. Implications for otters and other similar top predator’s conservation are discussed.

Four species of otters (Mustelidae, Lutrinae) occur in Southeast Asia and are considered to be of conservation concern: Aonyx cinerea (Asian small-clawed otter), Lutra lutra (Eurasian otter), Lutra sumatrana (Hairy-nosed otter), and Lutrogale perspicillata (Smooth-coated otter). Among these, L. sumatrana is endemic to the region, yet little is known about its biology, and the precise distribution of all four species in Southeast Asia is not well known. Furthermore, the taxonomy and systematics of L. sumatrana and L. perspicillata have been the subject of controversy, which has implications for the legal protection and for conservation programs of these taxa. To resolve these controversies, we used a multigene data set comprised of segments from 13 nuclear and 5 mitochondrial loci (11,180 nucleotides) to evaluate the phylogenetic relationships of Asian Old World otters. Phylogenies were also estimated using two mitochondrial loci (1,832 nucleotides) obtained from two or more individuals of the four Southeast Asian species. The results from maximum parsimony, maximum likelihood and Bayesian inference showed that L. sumatrana and L. lutra are sister taxa, whereas L. perspicillata is sister to A. cinerea. Furthermore, the results from the two-mitochondrial gene analyses indicate that L. sumatrana is reciprocally monophyletic with respect to L. lutra, supporting the specific validity of the former taxon. Signs such as tracks and feces are often used in field surveys to provide information on the distribution and abundance of otters, but the accuracy of these methods may be compromised when several closely related species occur sympatrically. Therefore, the two-gene data set was used to develop a provisional set of diagnostic nucleotides that can be potentially used to identify the four species of Southeast Asian otters from noninvasively collected biological samples, such as feces.

The sub-species Martes martes minoricensis was described using craniometric data being larger in size than populations living on the European continent ( M. m. martes ). A new sample of 39 animals (22 males and 17 females) of this sub-species from Minorca was pooled by sex and age, and 26 craniometric variables were analysed and compared with 104 Iberian pine martens (73 males and 31 females). Age was determined through readings of the cementum layers of the teeth, enabling distinctions to be made between adult and young animals. Further data is shown regarding the characterisation of the sub-species in terms of these measurements and its sexual dimorphism for these variables. The values obtained enable us to identify the larger size of the Minorcan individuals, both males and females, in relation to those from the mainland, there being a development in the longitudinal characters of the facial bones. With regard to sexual dimorphism, the differences are similar to those found on the continent, males being on average 10.6% larger than females. However, we also found notable differences at the level of the facial bones. Some hypotheses regarding this segregation between the sexes and the larger size of individuals in relation to continental populations are discussed.

Direct observation of Eurasian otters was used to demonstrate the characteristics and interannual use of small patches of habitats by females and litters in stretches of two rivers in north‐east Spain. During censuses and other vigils, 215 otter sightings (involving 265 otters) were obtained, 14–18% of which were observations on females and litters. Thirty‐five additional sightings were obtained in stretches used by litters of large cubs (47 individuals). Six small cub (2‐ to 6‐month‐old) and 15 large cub (>7‐month‐old) different family units (litters) were detected in both rivers as a whole. Average sizes of litters of small and large cubs were significantly similar, being respectively 1.17 (sd=0.41, range 1–2, n=6) and 1.27 (sd=0.46, range 1–2, n=15), so mortality of cubs was low at the period before dispersal. Litters were detected in significantly different patches from other otters, and litters of small and large cubs were also found in significantly different river sections. Litters of large cubs used small home ranges and core areas, and selected sections at reservoir tails, reservoirs, wider stretches, rough waters and refuges. Small cubs were found in narrow river stretches with calm waters. Selected patches had sheltered zones with abundant fish. This reduced use of space may result in the low rate of mortality.

This study describes the diet of European mink (Mustela lutreola) in Northern Spain. The diet was analysed from 105 European mink samples. Moreover, we collected other 37 faeces from a radiotracked European mink male. The European mink diet was based on small mammals (relative frequency of occurrences 36,9%), fish (30,6%) and birds (17,8%). The Levins index of trophic-niche width was 3,76. Wood mouse Apodemus sylvaticus was the most consumed small mammal and Cyprinids -mainly Barbus sp. was the most consumed fish. The average size and weight of consumed fish were 13,5 cm and 31,5 g, respectively and males consumed larger and heavier fish than females.

Litters of small Eurasian otter (Lutra lutra) cubs ranged from one to four, with those of one and two accounting for 95%. Significant variations were found between locations and according to the main diet (average ranging between 1.1 and 2.4 cubs/female). We found a seasonal pattern in otter breeding in some areas, being different in each. In the Prepyrenees, most births took place between March and June (85%). In Mediterranean rivers of the Ebro basin, most births occurred between December and February (57%). In both, the small cubs were found outside the dens just 2–3 months after the time of birth. Fish and crayfish exhibited a seasonal fluctuation, with a maximum density of biomass between the end of spring and the end of summer and minimum densities in winter. Water was always flowing in the Pyrenees and Prepyrenees rivers; however, in Mediterranean rivers, important periods of drought were observed, concentrated especially in summer and some winters. Timing of birds corresponded to variation in abundance of food (energy needs) and water resources in space and time. The presence of adequate prey species for the cubs (Ebro's barbel (Barbus graellsii and Barbus haasi) and American crayfish (Procambarus clarkii) in our study area) plays an important role. Interannual variations in food can affect the otter's reproductive cycle and breeding success.

Recent studies show that the availability of prey influences the ecology of otters by regulating breeding, carrying capacity and mortality. Mediterranean habitats experience extreme seasonal variation in water flow – a stress period can occur in summer when water flows and levels are low with long periods of drought, while torrential floods usually occur in autumn and spring. Reservoirs can affect this situation by further influencing water flow regimes and acting as a barrier. Our data show the close relationship between the amount of food (fish) available to otters and their use of a stretch of water and the otter density there. The adjustment of the number of individuals (and carrying capacity) in an area can be seen from their mortality, a decrease in their reproductive success, or migration. Our results are consistent with the hypothesis that otters are food-limited. Torrential rains, summer droughts and dams for water management have repercussions for otter populations in as much as they affect their prey-species. Barbels Barbus spp. and, secondarily, nases Chondrostoma spp. are shown to be important to otter ecology and breeding in Mediterranean Iberian rivers. The conservation and management of the otter in these habitats must not ignore the management of food sources. In order not to affect otter populations, the effect of the reservoirs and their dams also must be considered. The release and cessation of floodwater from reservoirs must be progressive and mimic more closely the flow regime of natural rivers.

At the end of the 1970s otter surveys were developed to study the distribution of the Eurasian otter Lutra lutra. The method was quickly adopted and expanded to include other species of otter. Different methods to estimate otter density were also used. There is some uncertainty, however, as to the significance and precision of the results. Otter surveys, radio-tracking studies and otter censuses (tracks and visual) were conducted in the same areas simultaneously. Comparison of the home ranges of otters tagged with transmitters with the results from otter surveys carried out in the same areas showed very similar otter distribution. Some 71% of those sites examined in which only one otter lived were positive, and 97% of those sites with two or more otters. Differences were found between different watercourses. In small or average sites with waterways, one single otter was capable of marking many kilometres so that it could be detected in most of the conventional 600 m sites (here 71% of sites). The data obtained by radio-tracking showed that almost all otters can be seen by experienced observers, confirming the validity of visual censuses. A high correlation was found between the number of otters seen during visual censuses and the number of otters detected by means of the length of their footprints. Using new and old tracks (2-days-old or more) the number of otters was overestimated.

In total, 298 transects (each 600 m long) were surveyed between 1987 and 1995 for otter Lutra lutra (Linnaeus, 1758) signs (spraints, smears and jellies) in nine rivers of NE Spain. Also two stretches of the rivers Noguera Ribagor^ana (length 2 km) and Noguera Pallaresa (length 2.6 km) in the Spanish Pyrenees were surveyed monthly between November 1989 and October 1990 for all otter tracks and signs. In both cases, all stones, rocks, beaches, hollows, caves, walls, shelves, and vegetation in the river and bankside within a 5 m band from the river edge (each side) were examined. The type of substrate on which findings were made was noted together with, the number of signs at a site. A seasonal pattern was found for the Pyrenean rivers with greatest sign density in winter and spring. In Mediterranean rivers, seasonality was not evident, founding even more signs in summer in some stretches. A total of 547.0 signs/km were recorded on the river Noguera Ribagor^ana during a year of study, of which 9.6% were smears, 1.0% jellies and 89.4% spraints. On the river Noguera Pallaresa 261.5 signs/km were noted, of which 9.2% were smears, 1.1% jellies and 89.7% spraints. A variation in sign deposition substrata (earth-beaches, grass, and rocks) and site (banks, middle river islands, caves/cracks, and river-stream confluences) throughout the year was observed. In the Noguera Ribagorgana stretch, periods of greatest sign deposition appear to be related to the presence of cubs. In accordance with the theory of the marking of resource use, a number of the spraints might not be significant, but rather the result of immature cub behaviour.

Levels of organochlorine compounds (PCBs, DDTs, HCHs and Heptachlor epoxide) were measured in fish species inhabiting the rivers of Catalonia, one of the most agriculturally and industrially developed areas of Spain. Although no time-trends in contamination levels can be determined because of the absence of data, a clear geographical distribution pattern is observed, with higher levels of contamination occurring in the lower reaches of the rivers. The Rivers Ebro and Ter show the highest levels of organochlorine compounds (mainly PCBs and DDTs). Furthermore, high levels of PCBs were found in an area of the Pre-Pyrenean mountains, which could be explained by aerial transport. The PCBs and pp'DDE were found to be widely distributed and were present in all the samples analysed. The other compounds analysed occurred in more than 79% of samples. Mean values ranged from 0.001 mg/Kg for α-HCH to 0.181 mg/Kg for the PCBs, wet weight basis, and 0.11 mg/Kg for α-HCH to 17.84 mg/Kg for the PCBs, lipid weight basis. Most observed levels fall within those recommended for human consumption, although heptachlor epoxide may exceed permitted levels in some areas. However, the threat to wildlife may be considerable due to biomagnification and, particularly, to sensitive species situated high in the food web, such as the otter (Lutra lutra).

Adult and sub-adult otters Lutra lutra (Linnaeus, 1758) caugh and consumed 3.36 prey (fish) per hour (n=32 captures). This represents 273.8 g of wet mass/h of activity outside the rest sites. (10.5-13.1% of the day) and it is enough to get their daily needs. Otters ate the pray without hiding on average (n=93) 0.46 m from the bank (up to 3.9 m) and 0.25 m above water level (up to 2.05 m). Prey weighing less than 150-200 g were consumed entirely, for this reason prey remains are very rare (except large trout, American crayfish and gravide cyprond females). Unpleasant tasting or toxic parts and sharp or wide parts of the bones, scales, teeth, claws, heads or leggs in large prey were not eaten.

Ruiz Olmo Jordi. Conservation of European mink in Catalonia Project Life Nature LIFE 02 NAT/E/ 8604. In: Ecologia mediterranea, tome 29 n°1, 2003. p. 111.

Les modifications de la distribution du vison d'Europe (Mustela lutreola) entre 1950 et 1999 sont decrites, avec 258 nouvelles donnees pour l'espece. Toutes les donnees proviennent du nord de l'Espagne (Pays basque, Rioja, Navarre, NO Aragon, NE Castilla-Leon) avec quelques-unes du sud de la Catalogne. Le type de donnees s'est modifie au cours du temps. La quantite d'animaux tues par l'homme a diminue alors que la mortalite due a la route a augmente. Entre 1980 et 1999, les visons ont ete trouves dans 99 carres UTM (10 x 10 km), et dans seulement 85 carres depuis 1990 (2,0 % et 1,8 % du territoire espagnol, respectivement). M.lutreola existe sous forme de trois noyaux de populations, plus ou moins connectes. On peut emettre deux hypotheses principales pour expliquer la repartition actuelle du vison d'Europe en Espagne; (1) M lutreola se trouve en Espagne depuis avant le XIX e siecle, au sein de son aire historique, et (2) M. lutreola a rejoint l'Espagne recemment (au cours du XX e siecle) a partir du SO de la France, par une extension au sud. Nos donnees semblent confirmer cette derniere hypothese. Meme si des visons d'Europe ont ete trouves dans des rivieres fortement polluees, ils evitent en general les eaux polluees. De plus, l'etablissement, a l'interieur de l'aire de repartition du vison d'Europe, d'une population de visons d'Amerique dans le nord de l'Espagne, et l'expansion de la grosse population de visons americains depuis le centre de l'Espagne, ainsi que la presence d'ADVirus chez plusieurs visons d'Europe constituent de serieuses menaces pour sa survie en Espagne.

Serious declines in populations of native European mink (Mustela lutreola) have occurred in Europe. One responsible factor may be infectious diseases introduced by exotic American mink (Mustela vison). In order to investigate a possible role for Aleutian mink disease parvovirus (ADV), we surveyed native riparian carnivores and feral American mink. When serum samples from 12 free-ranging European and 16 feral American mink were tested, antibodies to ADV were detected from three of nine European mink. ADV DNA was detected by polymerase chain reaction in whole cell DNA from four of seven carcasses; two American mink, one European mink and a Eurasian otter (Lutra lutra). Lesions typical of Aleutian disease were present in one of the American mink. A portion of the ADV VP2 capsid gene was sequenced and the results suggested that two sequence types of ADV were circulating in Spain, and that the Spanish ADVs differed from other described isolates from North America and Europe. Future conservation and restoration efforts should include measures to avoid introduction or spread of ADV infection to native animals.

The dramatic reduction observed in the distribution of the Eurasian otter (Lutralutra ) during the latter half of this century has been largely attributed to pollution(MacDonald, 1991). Attention has focused on organochlorine compounds, inparticular PCB (Mason 1989; Olsson and Sandegren 1991; MacDonald and Mason1992). The scarcity of the otter, and protection afforded, has meant tissue samplesare difficult to obtain and has led to fish, the principal prey, being used in manystudies (Hider et al. 1982; Olsson and Sandegren 1991; Smit and de Jongh 1991).Studies combining both otter and fish tissue samples from the same location,however, are rare (Foley et al. 1988; Smit and de Jongh 1991) due primarily tothe difficulty of obtaining samples of this mustelid. Bioconcentration factors ofthese pollutants have not, therefore, usually been calculated for this species in thewild. To address this shortcoming fish were analyzed from sites where ottersamples were taken. Fish constitute between 95-100 % of the otter’s diet in thearea of study (Ruiz-Olmo 1995). This area is constituted by three rivers(Noguera Ribagorzana, Noguera Pallaresa and Segre) where live the last otterpopulations in Catalonia (Ruiz-Olmo 1995). These populations are completelyisolated by unsurmountable dams built in narrow gorges.The bioconcentration factors thus obtained allow theoretical concentrations of thesecompounds in otter tissues to be calculated from the mean levels found in fish:MATERIALS AND METHODSSix otters were found dead by different causes: road-traffic accident (4), hunted(1) and mother killed (1), in the N.E. Spain between 1988 and 1993. The corpseswere frozen at -20 °C until post-morten analysis. Each specimen was sexed (4males and 2 females), measured and removed the canine tooth to age (2 of 0+, and 1of 1+, 2+, 4+ and 6+ year category). Tissue samples from the leg muscle andliver were removed for organochlorine analysis. These data are included in anotherfuller study about the otter pollution in Spain (Ruiz-Olmo et al. in press). Fish,captured using electro-fishing, were taken from the stretch of the river (0-15km.) where the otters had been found. These were also frozen until the analysiswhen the weight and length were measured (Table 1). Fish tail muscle was used forchemical analysis.The samples were analyzed using gas chromatography, followingthe method described by Lopez-Martin et al. (1994).

We studied the basic biology of the Red Fox (Vulpes vulpes) and its interactions with the waterbird colonies in the Ebro Delta natural park, Spain. Dens (earths) were found in areas characterized by sandy dune vegetation, a few buildings, areas where human entry was prohibited, and areas where hunting of waterfowl was banned. Regression associated the presence of dens to the abundance of dunes, halophytic vegetation and prohibited entry. Birds constituted 96% of the prey found at dens, mainly waterfowl (68%), gulls (16%) and rails (10%), but this differed markedly between areas. During the breeding season, foxes obtained their food from a reduced number of sources in the area surrounding their dens, and impacted the nearest breeding birds. We propose changes in the management of foxes in the natural park to safeguard internationally threatened bird species and to prevent them from decreasing, or even disappearing, as a result of fox predation.