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The lack of information on the protection status of birds in the winter period is a serious concern, as the survival of many populations depends on this period. Here, we consider the seasonal changes in distribution patterns of bird species in central Spain to assess the value of protected areas ( PA) for simultaneously conserving breeding and wintering avifauna. We used a stepwise algorithm of complementarity to select the minimum set of Universal Transverse Mercator 10 × 10-km squares containing all species at each period and then contrasted selected areas in order to test the degree to which breeding and wintering birds overlap. Using Gap analysis, we identified areas that are still unprotected. Our results show both a weak correlation and a scant overlap between areas that are important for bird conservation during breeding and wintering periods. Thus, we conclude that valuable areas for bird diversity differ between seasons, implying that breeding hot spots are not good surrogates for overwintering hot spots. This paper addresses the need of identifying not only important areas for breeding birds, but also wintering birds, revealing potential gaps in current PA networks. Future conservation policies should take these results into account in order to optimize bird conservation, especially considering that the appropriate protection of the bird species overwintering in Spain will, overall, benefit European breeding populations. [ABSTRACT FROM AUTHOR]

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There is a lack of studies designed to detect the most important areas for bat conservation. In this context, areas of high bat activity have been rarely considered in the delimitation of protected areas for bats, which are generally focused on the protection of roosting sites. This has been due to the difficulties of sampling the distribution of these nocturnal animals when moving at night. This methodological constraint has been overcome by the development of bioacoustic sampling, which allows mapping the occurrence of active bats over large areas. In this study, we use bat detectors to sample the distribution of bat activity in central Spain. This region is under the environmental effects of a mountain range (Guadarrama Mountains) and the urban encroachment of the city of Madrid. The occurrences provided by the detectors were used to produce species distribution models of which the resulting layers were arranged to detect the most suitable areas for bat richness and rarity indices. We performed a gap analysis to explore whether the areas most commonly used by active bats are covered by the current network of protected areas. The results showed that the best areas of high bat activity are located at the piedmont of the mountains and that most of these areas overlap with the existing network of protected areas. The best areas for bats excluded the most urbanized areas and within a similar urban gradient, protected areas tended to be located within the best sites for conservation. These results suggest that bats currently benefit from a network of protected areas initially aimed to protect birds and habitats (Natura 2000). In addition, monitoring areas of high bat activity could complement roosting site protection in the conservation of bat assemblages. [ABSTRACT FROM AUTHOR]

Agricultural intensification over the last 60 decades has been linked to decreases in biodiversity and in the breeding populations of several avian species in farmlands. However, agricultural intensification has not affected all species in the same way and transformed landscapes can still provide suitable habitats for species tolerant to some degree of anthropogenic change. Understanding habitat selection in man-made landscapes is a pre-requisite to effective management and conservation of the species that use them. However, habitat-related choices made by individuals occupying these landscapes are often difficult to explain, as the cues they use may be decoupled from the ecological context in which they evolved. Here, we investigated nesting habitat selection in a ground-nesting raptor breeding mainly in wetlands, which, unlike many other species occupying farmlands, has experienced a population increase in some agricultural regions. We used multivariate analysis to assess the extent to which habitat characteristics, human disturbance or proximity to other occupied sites influenced nesting-site occupancy. Our results indicate that Marsh harriers occupied breeding sites according to habitat cues obtained at two complementary spatial scales (i.e. the breeding site and the foraging area). This study indicates that a raptor species that uses human-made structures such as ponds for breeding while exploiting their surrounding crops for hunting can take advantage of agricultural intensification. Environmental disturbances are often viewed only in terms of their harmful impacts on the affected species. However, human activities are causing many types of alterations in natural landscapes that can be exploited by certain species with positive responses towards these transformations. The adaptation of some raptors to human-altered environments, such as the Marsh harrier in our study area, raises doubts regarding the appropriateness of using such species as indicators of natural habitat quality. [ABSTRACT FROM AUTHOR]

Limitation of disturbing activities around the breeding areas of protected species is not always possible, if these activities are economically important and have, in addition, positive effects on protecting the habitats of those protected species. Searching for optimal solutions making commercial exploitation of natural resources compatible with biodiversity conservation is thus of concern to managers and policy makers. This is the case of the cinereous vulture Aegypius monachus, breeding primarily in cork-oak woodland, and cork exploitation, a traditional socio-economic activity carried out in several Mediterranean countries, and critical for the maintenance of this important habitat. We studied the effects of this anthropogenic activity on the behaviour and breeding success of breeding cinereous vultures in Spain. For the adults, the probability of nest abandonment was dependent on the distance of workers from the nest and the level of noise; activities within 500 m from the nest were likely to cause abandonment of the nest by adults, if the level of noise was intermediate or loud. Neither the size of the working group nor the use of machines per se, had any effect on the probability of nest abandonment. Pairs in an area of the colony exposed to intrusive anthropogenic activity had 20% lower breeding success than those in the same colony that were not exposed to these disturbances. If the application of buffer zones of 500 m is not possible (as is likely given the economic losses involved), several alternatives are recommended based on our results to minimize the impact of these activities, in particular to diminish the noise level of cork extraction activities. Observational studies like this help understanding the magnitude of the problem and finding alternative solutions for harmonizing conservation and economic development. [ABSTRACT FROM AUTHOR]

The European wild rabbit Oryctolagus cuniculus has been recently reclassified as Near Threatened in its natural range in the Red List of Endangered Species by the IUCN, and a huge conservation effort is being undertaken in Spain for this keystone species. Restocking is a frequent measure for wild rabbit population reinforcements and it is also part of predator conservation programmes. However, it can have a negative influence on the resident rabbit population when it is not carried out carefully. In our work, using a model selection procedure based on a theoretic information approach, we analyze which factors favor the presence of sarcoptic mange in some wild rabbit populations in Catalonia (north-eastern Spain), as well as the trend of rabbit abundance in affected and non-affected hunting estates. Presence of mange depends on animal abundance and on restocking numbers (22.09%). From the mean rabbit abundance (30 rabbits hunted km) and the mean restocking rate (18 rabbits km), the probability of being affected increased in nearly 5% when the restocking rate increased in one unit. Rabbit abundance (2001-2007) depends on the presence of mange and on the effect of the year (23.86%), and clearly declined in the hunting estates with mange, whereas abundance is maintained in mange-free zones. Our results indicate that a sanitary control is necessary when restocking wild rabbit populations. Furthermore, restocking is shown to be a potential way of introducing pathogens to resident populations, especially under conditions of high density. [ABSTRACT FROM AUTHOR]

Bird mortality as a result of collisions with power lines has been of increasing concern in recent decades, but the real impact on bird populations requires an experimental assessment of scavenger removal rates and searcher detection errors. Farmland and steppe birds, two of the most threatened avian groups, have been shown to be particularly vulnerable to collision with power lines, but few removal and detectability studies have been developed in cereal farmland habitats, and none in the Mediterranean region. We conducted five carcass disappearance trials in central Spain by placing 522 corpses of different sizes under power lines, and searching for remains four times during the following month. The influence of several factors was examined using multivariate approach. The accumulated number of carcasses removed by scavengers increased logarithmically, with 32% removed over the 2-day period after the initial placement, but only 1.5% removed on a daily basis by day 28. Small birds disappeared earlier and at a higher proportion than larger birds. Carcass removal rates were site-dependent, but were not influenced by carcass density or season. The detection rate increased with the observer's previous experience and carcass size. Carcass counts at power lines notably underestimate bird casualties. Our 4-week disappearance equations provide a full range of scavenging rates and observer efficiency correction factors for a wide range of bird weights. Fortnightly to monthly search frequencies may be adequate to detect medium- to large-sized corpses, but are insufficient for smaller birds. Finally, all personnel participating in carcass searches should be trained previously in this task. [ABSTRACT FROM AUTHOR]

Positive interactions between species can have important conservation implications, especially when the species associating are both vulnerable. We studied the habitat use of pin-tailed sandgrouses Pterocles alchata and their association with another vulnerable species, the little bustard Tetrax tetrax in agrarian pseudo-steppes of central Spain using radio-tracking. The occurrence of mixed-species flocks varied seasonally, being more frequent in winter (65% of pin-tailed sandgrouse flocks). In this season, pin-tailed sandgrouses preferred stubble fields and fallows. Moreover, we found that habitat selection of pin-tailed sandgrouse depended on the association with little bustards in mixed-species flocks. When in mixed-species groups, sandgrouses changed their agrarian substrate preferences, and used stubble fields significantly more often than when in sandgrouse-only flocks. We also provide evidence that pin-tailed sandgrouse benefited from the anti-predator vigilance of little bustards, allowing sandgrouse to exploit new feeding grounds (stubble fields) that would otherwise be too risky to exploit. Our results indicate a close positive association between these two species, which are both declining in Europe, and we discuss implications for their management and conservation. We also recommend taking into account inter-specific positive interactions when designing conservation strategies for threatened species. [ABSTRACT FROM AUTHOR]

In a conservation context, food supplementation is a management tool used to reverse the decline of food-limited populations by means of positive changes in behaviour and fitness that may be reflected in population parameters. The critically endangered Iberian lynx Lynx pardinus has suffered a dramatic decline primarily because of the severe drop of its main prey, the European wild rabbit Oryctolagus cuniculus. To reverse this situation, a food supplementation programme has been implemented in Doñana, south-west Spain, since 2002. In this study, we assess the utility of providing artificial food to reduce home-range (HR) size, and to increase productivity, survival and recruitment in a scenario of low lynx density, as compared with reference data from the same population in the absence of extra food. Food supplementation produced a significant contraction of core areas, but not of complete lynx HRs. We did not detect any significant change in productivity or dispersal rates, but supplementation could have helped transient adult lynx to settle down. The positive effects of food supplementation may have been partly countered by factors such as inbreeding, Allee effects and disease outbreaks, whose effects may have been exacerbated in this small lynx population. Food supplementation, however, proved useful to retain individuals, to keep range sizes within their normal range of values, thus maintaining spatial organization, and to allow lynx reproduction and kitten survival in areas with very low prey density. Therefore, we recommend keeping an extensive and intensive supplementary feeding programme until the density of wild rabbits will enable the viability of this endangered lynx population. [ABSTRACT FROM AUTHOR]

Animals make decisions relying on environmental cues associated to high survival or breeding success along their evolutionary history. However, because of rapid anthropogenic changes in the environment, they may lack useful cues, making bad decisions with potential consequences for individuals and populations. Contaminants are difficult or impossible to detect for animals, so polluted habitats could be used in spite of their dangerous effects. The Eurasian otter Lutra lutra reoccupied the Guadiamar River (SW Spain) <1 year after a toxic spill that killed the fauna living in it. The levels of heavy metals and arsenic (As) in the river trophic web at that moment were probably harmful for otters. To investigate this, we determined the amount of several heavy metals including copper, cadmium, zinc (Zn) and lead (Pb) and metalloids such as As in otter faeces and estimated the exposure of otters to these elements as average ingestion. Concentrations of Zn, Pb and As were statistically higher in faeces collected along the Guadiamar River than in those collected along the Guadalete River (reference area). An ‘average otter’ in the Guadiamar River would consume 3–4 mg of Pb and more than 5 mg of As daily. Such doses must be hazardous for the species and challenge the usual assertion that otter presence is a good indicator of river quality. [ABSTRACT FROM AUTHOR]

The conservation importance of the post-fledging period in migratory birds has been scarcely assessed. In this study, we examined the space use and habitat selection of radio-tagged lesser kestrels Falco naumanni at two spatial scales during summer in north-western Spain, where premigratory aggregations of around 1000 lesser kestrels occur. Space use was estimated by kernel accounting for the spatiotemporal autocorrelation of the radio locations, and habitat selection was analysed by weighted compositional analysis accounting for the intensity of use. Kestrels moved within 9 km around roosts during daylight and returned daily during sunset to the same roosts, exhibiting refuging behaviour. They foraged on average 3.7 km from the roost in an area of 346.8 ha (home range), 92.7 ha of which were used intensively (core area). Within these areas, lesser kestrels intensively used more farmland than any land-scale habitat. Within farmland, kestrels significantly avoided the irrigated crops. This avoidance seemed to be due to the difficulty of prey access and/or scarcity of prey available. Conservation plans of lesser kestrel should include the post-fledging period by legally protecting roost sites and maintaining dry farmland systems around the communal roosts. [ABSTRACT FROM AUTHOR]

Because of potential conflicts between commercial and conservation interests, one challenge in coastal-area management is how to regulate harvesting practices in coastal areas without adversely affecting the survival of migratory waterbirds. In most Spanish intertidal areas of importance for shorebirds, managers have concentrated only on stock management of the shellfish species. Here, we studied aspects of the foraging behaviour of Eurasian curlews Numenius arquata migrating through a Ramsar area in north Spain in the presence and absence of hand harvesters. We aimed to assess potential negative effects on curlews with a view to making coastal management recommendations that would help reduce conflict between local people and waterbirds. The average density of hand harvesters and foraging curlews at low tide was 0.56±0.09 persons per 10 ha and 16.47±0.73 birds per 10 ha, respectively. The presence of harvesters had a significant effect on foraging activity (no harvesting: 86.47±1.01%; harvesting: 82.70±1.00%). However, the absence of significant differences in all other foraging variables, between days with and without harvesting, indicated that curlews were able to compensate for the impact of harvesters on their foraging activity. We recommend, as a point of departure, that intertidal coastal managers of this Spanish site and similar areas of importance for shorebirds limit the harvesting load to <0.56 persons per 10 ha−1 at least during autumn migration. [ABSTRACT FROM AUTHOR]

Rana iberica is an Iberian endemic with populations mainly distributed in northwestern Iberia, but with scattered populations along the Sistema Central in central Spain. These latter populations inhabit mostly mountain areas and are endangered due to habitat loss and fragmentation. At present, no information about genetic variability and gene flow patterns between populations is available and, consequently, it is unknown to what extent geographical fragmentation might have caused restrictions to gene flow. We used six microsatellite loci to characterise genetic variability in R. iberica populations from the Sistema Central. We analysed samples of 142 specimens from 15 populations in this region and another two from additional locations in the Iberian Peninsula. The number of alleles per locus observed ranged from four to 15. Allelic richness, percentage of private alleles and gene diversity was significantly lower in populations from the Sistema Central, where inbreeding coefficients were relatively high. Analysis of molecular variance (AMOVA) and estimated FST values indicated the existence of genetic substructuring within this region and suggested the existence of restrictions to gene flow in geographically close populations. Low heterozygosities and a trend towards lower values of genetic variability from western to eastern populations within the Sistema Central suggest that R. iberica has colonised this region recently. We hypothesise that the observed pattern is due to the interaction of both historical (reduced genetic variability in peripheral populations) and present-day (anthropogenic habitat loss) factors that confirm the vulnerable status of populations of R. iberica in central Spain and point to the need for adopting measures directed towards the preservation of existing habitat. [ABSTRACT FROM AUTHOR]

We studied variables affecting spatial and inter-annual variations in presence/absence and abundance of little bustard (Tetrax tetrax) males in extensive cereal farmland in central Spain. Both variables were positively influenced by the percentage of arable surface and also by substrate heterogeneity. In addition, male abundance varied significantly between years and among sectors of the study area, even when taking into account variation in landscape variables. A significant interaction between year and sector showed that abundance variations did not follow a fixed pattern, meaning that interannual variation in male abundance among sectors cannot be predicted. We discuss potential alternatives to explain such variation, as well as the implications of our results for the species' population estimates, status assessment and conservation. [ABSTRACT FROM AUTHOR]

The author comments on a study about the outbreak of feline leukemia virus (feLV) infection among endangered Iberian lynx in Spain. She commends the study authors for providing an excellent example of how endangered species can be managed. She says that the study was able to show the dynamic and unpredictable nature of pathogen invasion outcomes. The author adds that the study demonstrated that the value of long-term monitoring should not be over emphasized.