Rabbit Abundance Research Articles

Satellite tracking of wild dogs in south-eastern mainland Australian forests: Implications for management of a problematic top-order carnivore

Satellite tracking was used to follow the movements of a problematic top-order carnivore, the wild dog (Canis lupus dingo, C. lupus familiaris and their hybrids), in contiguous forested landscapes in south-eastern mainland Australia. Home range sizes of wild dogs were much larger than previously determined using conventional telemetry methods, averaging 10,000ha with a maximum size of 59,000ha over approximate 3-month periods. Wild dogs at sites with high abundance of kangaroos, wallabies and rabbits had smaller areas of occupancy than did dogs at sites with low availability of these preys. Despite mostly large home ranges, tracked animals were loyal to publicly-owned tenure and there were few instances where individuals moved large distances on to adjacent private tenure. Instead, movement behaviours of most tracked animals were characterised by repeated short distance forays, often at acute angles from previous locations. Consequently, home ranges were stable and otherwise well defined. Analysis of DNA from our study animals indicated that most individuals were of ‘dingo’ ancestry, but otherwise considered hybrids because of the presence of domestic dog genes. Only two of 24 animals could be considered as ‘pure’ dingo. Contemporary wild dog management demarcates lands where control is or is not undertaken, with the latter notionally acting to ‘conserve’ dingoes. Due to the large scale of movement of animals, existing control efforts likely impact over a greater area than previously suspected. Furthermore, our genetic findings suggest that conservation of dingoes in south-eastern mainland Australia is difficult to achieve. A modified approach to wild dog management is needed, taking account of the extent of range of individual animals and the existing genetic characteristics of populations.

Micro-scale distribution of rabbits on Fuerteventura Island

The European rabbit (Oryctolagus cuniculus) is a conservation and social dilemma in the Canary Islands. It is the main prey of endangered species, it causes severe impacts on vegetation, as well as has a considerable hunting economic value but damages agriculture. We assessed drivers of European rabbit habitat selection on Fuerteventura Island (Canary Islands, Spain) in order to understand the ecology and to contribute with data for managing this introduced species. To measure rabbit abundance, we counted the total number of fresh pellets and latrines. We used Generalized Linear Models (GLMs) to analyze the relationship between rabbit abundance and four groups of variables that represented the biological requirements of the species (environmental, food resources, refuges/shelters, and biological interactions). Hierarchical partitioning techniques were used to estimate the explanatory capacity of these different groups of variables. Our model better explained fresh pellet abundance (89% of total deviance) than latrine abundance (57%). Variables related to food resources best explained the abundance of both latrines and pellets. We identified a set of plant species highly correlated with rabbit abundance, which probably makes up the species’ diet. Variables relating to refuge/shelter and the environmental were also relevant. Interactions with other mammals did not strongly affect rabbit abundance on Fuerteventura Island. Mean annual precipitation and temperature were variables that individually best explained abundance, although half of their relevance is shared with others non-environmental variables. Our results provide policy makers and land-managers with applied information on the relationship between rabbit populations and micro-scale components of Fuerteventura.

Swamp rabbits in floodplain ecosystems: Influence of landscape- and stand-level habitat on relative abundance

Abstract Swamp rabbits (Sylvilagus aquaticus) are bottomland hardwood forest specialists that may serve as useful indicators of ecosystem health. However, no studies have assessed the influence of both microhabitat and macrohabitat variables on relative abundance of swamp rabbits. To address this gap in the literature, we assessed the influence of landscape- and stand-level habitat variables on relative abundance of swamp rabbits in 29 floodplain forest sites in southern Illinois during 2006–2007. Swamp rabbits were detected at 69% of the sites surveyed. The median contiguity index of the landscape (a measure of patch size and spatial connectedness), the range in contiguity index of upland habitats, and tree stump density were positively and moderately related (w+[i] = 0.381–0.475) to relative abundance of swamp rabbits. Our results emphasize the importance of large unfragmented patches of floodplain forest habitat to swamp rabbits, and confirm that continued fragmentation of remaining habitat could hav...

Conservation biogeography of ecologically interacting species: the case of the Iberian lynx and the European rabbit

ABSTRACTAim To relate the recent Iberian lynx decline to changes in the distribution of the European rabbit after the haemorrhagic disease outbreak of 1989. As Iberian rabbits evolved in two geographically separated lineages, being the recent lynx range practically restricted to the southwestern lineage, we also test if differential range dynamics exists for these lineages, with the consequent implications for lynx conservation and reintroduction planning.Location The Iberian Peninsula.Methods We modelled environmental favourability for the lynx based on its distribution before 1989, and for the rabbit using distribution data collected primarily after 1989, and validated them using independent abundance data. We compared both models and combined them in a lynx occurrence forecast. We correlated the prevalence of southwestern rabbit lineage with the environmental favourability for the rabbit.Results The environmental lynx model correlated with past lynx abundance data, but did not reflect its recent strong range contraction. The rabbit model correlated with recent rabbit abundance, but was negatively correlated with the environmental model for the lynx. The combination of both models forecasted lynx occurrence in a few separated nuclei, which encompass all recent lynx records. The prevalence of rabbit's southwestern lineage correlated negatively with favourability for the rabbit.Main conclusions The region to which the lynx became confined before 1989 is currently less favourable for rabbits, whereas more favourable areas remain outside lynx reach. This differential favourability correlates with rabbit phylogeographical structure, suggesting that the southwestern lineage is facing more unfavourable conditions or is less resilient to recent diseases. The loss of concordance between lynx distribution and the whole rabbit phylogeographical structure has prevented lynx persistence in northeastern rabbit lineage areas, which should be considered in lynx reintroduction planning. Similar conservation problems could affect other ecologically interacting species whose distributions’ overlapping has sharply diminished.

Influence of habitat management on the abundance and diet of wild rabbit (Oryctolagus cuniculus algirus) populations in Mediterranean ecosystems

During the last decades wild rabbit (Oryctolagus cuniculus) populations have been progressively declining in the Iberian Peninsula as a result of several factors, namely habitat deterioration. Hence, habitat management has become one of the most commonly used management techniques to restore wild rabbit populations. To test the efficacy of some of these measures (creation of pastures, opening firebreaks) in rabbit populations, two managed (M1 and M2) and two control areas (C1 and C2) were selected in the Portuguese Southwest (SW) Coast. In each study area, the influence of habitat management was tested assessing temporal changes in rabbit abundance obtained from pellet counts and in rabbits’ diet through microhistological analysis of fecal pellets. Rabbit densities were higher in managed than in control areas (mean annual values: M1–1.08 pellets/m2; M2–1.60 pellets/m2; C1–0.69 pellets/m2; C2–0.40 pellets/m2). In general, Gramineae was the most consumed plant group throughout the year and in all study areas. In control areas, consumption of alternative species with low nutritive value (e.g., Cistus ladanifer) was observed, especially in summer. Our data suggest a positive influence of habitat management on rabbit populations since in managed areas individuals presented an overall higher abundance and a more nutritive diet. In addition, there was no evidence that sown species were consumed in detriment to naturally occurring grasses, suggesting that in Mediterranean semi-arid regions clearing vegetation inside the scrubland might be sufficient to improve habitat conditions for rabbits.

European rabbit population trends and associated factors: a review of the situation in the Iberian Peninsula

ABSTRACT European rabbits are considered a keystone species in the Iberian Peninsula. Their populations have sharply declined over the past century, mainly due to habitat loss and the arrival of two viral diseases: myxomatosis in the 1950s and rabbit haemorrhagic disease (RHD) at the end of the 1980s. For the conservation of the Iberian Mediterranean ecosystem, it is important to determine whether rabbit populations are recovering two decades after the RHD outbreak, and to identify the factors associated with population recovery. Here, we review the current knowledge on recent rabbit population trends in the Iberian Peninsula and the factors associated with these trends. Although most rabbit populations are still declining in the Iberian Peninsula, a few seem to have recovered. In general, positive trends have been recorded in species‐friendly habitats characterized by non‐fragmented landscapes, interspersed patches of Mediterranean scrubland, good pastures and/or crops, soft soils that are suitable for warren construction and a Mediterranean climate with relatively high rainfall. Additionally, rabbits seem to be recovering better in areas where management practices (e.g. low hunting pressure, habitat management and predator control) are applied to increase their numbers. From these findings, it is possible to identify five broad objectives for rabbit conservation in the Iberian Peninsula. First, it is clearly necessary to establish a long‐term programme for monitoring rabbit abundance and trends on a large scale. Second, the conservation and restoration of open Mediterranean scrubland should be a priority for stabilizing and maintaining existing healthy rabbit populations. Third, despite the lack of experimental evidence, management activities aimed at increasing the quantity and quality of both refuge and food should continue to be implemented. Fourth, legislation on the timing of the hunting season should be revisited following recommendations made by scientists. Finally, experimental approaches are required to investigate whether the control of generalist predators is a successful strategy to allow rabbit populations to recover.

Response to Delibes-Mateos et al. : Pellet size matters

In Rueda et al. [Rueda, M., Rebollo, S., Gálvez-Bravo, L., 2008. Age and season determine European rabbit habitat use in Mediterranean ecosystems. Acta Oecol. 34, 266–273] we used a threshold of 6 mm faecal pellet diameter to differentiate between adult and juvenile European rabbit ( Oryctolagus cuniculus) habitat use. Delibes-Mateos et al. designed a housing experiment with 12 adult rabbits and criticised the choice of 6 mm as a threshold to separate adult and juvenile rabbit pellets, claiming that adults can produce pellets both larger and smaller than 6 mm in similar proportions. In response to their criticism we argue the following. The selection of a 6 mm threshold has a bibliographic basis, it is not a new method developed by Rueda et al. and produces consistent results when applied in the field. Assuming that Delibes-Mateos et al. results are accurate, we should have found a greater number of <6 mm pellets than >6 mm, overall and seasonally, which is not the case. We believe that the use of commercial pelleted food, keeping animals isolated in small cages for over a year, and the use of adult rabbits only, makes the experimental design used by these authors not suitable to refute the usefulness of separating rabbit pellets smaller and larger than 6 mm diameter as indicators of changes in the relative abundance of juvenile and adult rabbits in the field. Finally, we agree with the authors that the use of indirect methods of animal aging would require case-specific validation studies; however, we believe these studies should be correctly designed.

The presence and implications of viable seed in the faeces of invasive free-ranging European Rabbits and Red Foxes

Invasion by weeds and other undesirable plants threatens global biodiversity. However, the role of mammals in maintaining and spreading weeds is often overlooked. Here we confirm that two widely distributed and abundant Australian mammalian pests, the European Rabbit (Oryctolagus cuniculus) and the Red Fox (Vulpes vulpes), can spread viable seed. Our assessment mainly involved determining the number and viability of seeds recovered from faeces of free-ranging individuals inhabiting several areas within the Mediterranean region of south-western Australia, an internationally recognized biodiversity hotspot. In summer, viable seeds were recovered from 3?4% of the rabbit faecal pellets (n = 190) compared to 21?40% of pellets in autumn (n = 235). Ten (77%) of the 13 species of seed identified were weeds. Of the 1,136 seeds recovered, 16% germinated. In all, 13-30% of rabbits passed viable seeds in summer, increasing to 44?73% of rabbits in autumn. In captive wild rabbits, mean passage time of marked seed through the intestinal tract ranged from 4?7 h. This, together with the small home ranges of Australian European rabbits, suggests that they may generally disperse seeds over 1?2 km. Nine to 27% of foxes passed viable seed. Although 48% of scats (n = 62) contained whole seed, only 12.9% of all scats contained viable seed (range 9.1%?19.0%). Viable seeds (4/8) were also recovered from the hides of some shot foxes. In all, 63% (12/19) of seed species identified in the scats and pelts of foxes were weeds. Rabbits (primary dispersal) and foxes (primary, and secondary dispersal via seeds ingested with prey) may be important dispersers of viable seed, and may be essential for less common, but important, long-distance plant dispersal, particularly by some invasive species. Thus, suppression of weeds can be added to the benefits of reducing the abundance of rabbits and foxes to protect the unique biota and agricultural production in southwestern Australia.

Predator abundance in relation to small game management in southern Portugal: conservation implications

The interaction between hunting interests and legally protected predators is often a contentious conservation problem, requiring detailed understanding of predator responses to game management. This issue was addressed in southern Portugal in a treatment-control natural experiment, whereby the abundances of small game, corvids, birds of prey and carnivores were compared in 12 game estates (>500 ha) and 12 matching areas with similar sizes and land uses but no game management. European rabbits (Oryctolagus cuniculus), Iberian hares (Lepus granatensis) and, less so, red-legged partridges (Alectoris rufa) were far more numerous in game estates than elsewhere. Among legally controlled species, there were less Eurasian jays (Garrulus glandarius) but more red foxes (Vulpes vulpes) in game estates, though the latter were primary targets of predator culling. Fox abundance within game estates varied inversely with an index of management intensity (density of small game feeding sites) and increased along with hare abundance. As for protected species, only common kestrels (Falco tinnunculus) and genets (Genetta genetta) were fewer in game estates. The abundance of raptors within game estates varied inversely with gamekeeper density, whereas that of common buzzards (Buteo buteo) increased along with rabbit abundance. Overall, there was little evidence that game management reduced local predator abundances, except in the most intensively managed estates. Game estates provided concentrations of prey that was scarce elsewhere, which may have favoured increased abundances of some predators. Further investigations are needed to find out whether high prey densities may attract predators to game estates with increased mortality risk, which may thus become population sinks for protected species.

Carnivore population trends in Spanish agrosystems after the reduction in food availability due to rabbit decline by rabbit haemorrhagic disease and improved waste management

We conducted spotlight counts from 1992 to 2006 in 59 localities to describe carnivore presence, distribution and relative abundance in open agriculture lands in Aragon, northeastern Spain. During the study period, urban waste and carcases of domestic livestock became less available to wild animals, and rabbit (Oryctolagus cuniculus) abundance was low after rabbit haemorragic disease. We calculated a kilometric abundance index (KAI, individuals seen per 100 km surveyed) and the ratio between the number of positive localities in which a species was detected and the total of localities surveyed in a year. Indices to abundance and presence included: red fox (Vulpes vulpes), KAI per 100 km 10.70 and 100.0% localities per year; stray dog (Canis familiaris), KAI 0.48 and 22.6% localities; wildcat (Felis silvestris), KAI 0.10 and 19.1% localities; domestic cat (Felis catus), KAI 0.21 and 20.6% localities; polecat (Mustela putorius), KAI 0.02 and 2.0% localities; badger (Meles meles), KAI 0.16 and 23.6% localities; stone marten (Martes foina), KAI 0.11 and 19.6% localities; weasel (Mustela nivalis), KAI 0.002 and 0.6% localities; and genet (Genetta genetta), KAI 0.06 and 10.0% localities. Indices of badger abundance increased significantly, whereas indices of stray dogs decreased significantly over the study period. Abundance indices of red fox, the most important predator of small game, were stable throughout the study period. No significant trend was observed to other studied species. This study concludes that Aragon region maintains a diverse and rather stable carnivore community and shows that large scale data may help to identify trends of the more abundant wild and feral carnivores.

Seasonal Abundance and Management Implications for Wild Rabbits (&lt;em&gt;Oryctolagus cuniculus&lt;/em&gt;) on La Palma, Canary Islands, Spain.

There is little information on introduced European rabbit populations in the Canary Islands, an oceanic archipelago close to the north-west coast of Africa. Seasonal changes in rabbit abundance have important consequences for the management of this species. The study involved spotlight counts of wild rabbits over 3 years to characterize patterns of seasonal abundance through time and across insular biotopes. There were more rabbits at the beginning of summer than in late autumn or early winter in all years and biotopes. Coastal biotopes had more rabbits than had other biotopes, probably because of good grass cover, a factor associated with rabbit abundance. There was no seasonal change in rabbit abundance among biotopes. Adjusting hunting seasons to seasonal variations in rabbit abundance could be used to control populations of this species.

Rabbit (Oryctolagus cuniculus) abundance and protected areas in central-southern Spain: why they do not match?

European rabbits (Oryctolagus cuniculus), a keystone species in the Iberian Mediterranean ecosystem, are the staple prey of the Iberian lynx (Lynx pardinus) and the Spanish imperial eagle (Aquila adalberti). These predators require medium to high rabbit densities and a low degree of human disturbance. We compared rabbit abundances in areas of central-southern Spain under three levels of protection and management: protected areas, intensively managed (nonprotected) hunting estates, and other nonprotected areas. We used pellet abundance indices to estimate rabbit density in 118 surveys conducted during the summers of 2002 and 2003. We observed greater rabbit abundance in intensively managed hunting estates compared to protected areas and other nonprotected areas, perhaps because policy makers did not consider rabbit numbers when selecting priority areas. Alternatively, differences in game management practices (e.g., predator control or habitat management) may explain the higher rabbit densities observed in managed hunting estates. Our results suggest that the best feeding conditions for the Iberian lynx and the Spanish imperial eagle occur in intensively managed hunting areas, where such predators are frequently persecuted. The conservation of these endangered predators may require efforts to increase rabbit densities in protected areas.

Status and habitat changes in the endangered Spanish Imperial Eagle Aquila adalberti population during 1974–2004: implications for its recovery

AbstractThe distribution and abundance of Spanish Imperial Eagle Aquila adalberti populations between 1974 and 2004 were determined using information from national censuses. Its breeding area occupies the south-western quadrant of the Iberian Peninsula (Spain and Portugal) and is composed of 13 nuclei and 5 subpopulations. Since 1974, population levels in all nuclei, except the one in Doñana, have expanded. The non-breeding dispersion area, according to sightings of juvenile and immature individuals in quadrants of 10 x 10 km, coincided with that of the breeding area. Bibliographical information showed that halfway through the 19th century the Spanish Imperial Eagle was considered abundant, at least locally; and most cited breeding areas were in relatively human-occupied plains. Towards the end of the 19th century the population became scarce; remaining so for most of the 20th century, with remote mountain ranges being the most cited breeding habitats. The comparison between the data from the first census, in 1974, that located 38 territorial pairs, and the 2004 census that located 198 pairs, shows that: 1) percentages of pairs in plains have increased, while those in mountains have decreased; 2) the trophic quality of the habitat, based on rabbit abundance, has decreased, and 3) numbers of nests in both protected areas and on private ground have increased significantly. The type of land ownership did not seem to affect breeding performance. Populations have increased more outside protected areas than within, despite the availability of potential habitat. In the past century, legal protection and attitude changes towards this eagle seem to have been influential in preventing its extinction. At present, habitat management seems also to be an important factor in its continuing recovery.

Is habitat management an effective tool for wild rabbit (Oryctolagus cuniculus) population reinforcement?

Wild rabbit scarcity in Spain is a serious problem due to its economic and ecological value; thus, management techniques to reinforce their populations are being implemented. Translocations are traditionally applied but high short-term mortality by predation makes them unsuccessful and increases their biological cost. An alternative to translocation would be to strengthen local reduced populations through habitat management (building artificial warrens and increasing food availability). Here, we test this method to determine its efficiency as an exportable protocol to recover wild rabbit populations. We compare two areas with and without artificial warrens and increased food availability and assess relative rabbit abundance by means of pellet counts. Results show that, during the 2 years following habitat management, rabbit numbers increased in the experimental plot in contrast to the not managed one, suggesting its effectiveness to reinforce low-density rabbit populations.

Changes in immunity to rabbit haemorrhagic disease virus, and in abundance and rates of increase of wild rabbits in Mackenzie Basin, New Zealand

The evolutionary race between diseases and their hosts may lead to attenuation of the disease agent, increasing resistance in the host, or both. This is an undesirable outcome when the disease is being used as a biocontrol agent but a desired outcome when the host is valued by people. Introduced wild rabbits Oryctolagus cuniculus are a pest to agriculture and biodiversity values in New Zealand’s grasslands, particularly on the drier eastern sides of both islands. The costs to manage them using conventional control could not be sustained by landowners who since the 1980s have proposed the introduction of the viral biocontrol agents myxomatosis and then rabbit haemorrhagic disease virus (RHDV). Myxomatosis failed to establish but RHDV did establish and spread following its illegal introduction in 1997. However, since 1997, rabbit haemorrhagic disease (RHD) has become less effective for biocontrol of rabbits in New Zealand. Three lines of evidence from our four study sites in the Mackenzie Basin support this claim. First, the proportion of rabbits of all ages with antibodies to RHDV has increased in samples of rabbits shot each year since 1997. Taken alone this may simply reflect an accumulation in cross-sectional samples of seropositive older rabbits that have been exposed to infection but survived successive epizootics. Second, the proportion of young rabbits, sampled at an age when they have been exposed to a single epizootic event, that have antibodies to RHDV has also increased since 1997. This is strong evidence that something has changed in the rabbit–virus interaction. The cause of this effect remains unknown but is reflected in the third line of evidence, that the abundance of rabbits as indexed by standardised spotlight counts has increased since 1997. The rate of increase has, however, been much slower than that seen in the same populations as they recovered from conventional control before the arrival of RHD. Thus, we conclude that RHD is still an effective biocontrol but its efficacy is waning.

Rabbit populations and game management: the situation after 15 years of rabbit haemorrhagic disease in central-southern Spain

Over recent decades wild rabbit populations have undergone a sharp decline in Spain with consequent negative impact both on a game-based economy, and on the conservation of threatened species that depend on rabbits. We investigated the relationships between rabbit population change and habitat and game management in central-southern Spain. To determine recent rabbit population changes we revisited 60 localities during summer 2002 to repeat surveys previously carried out in 1993. Each survey consisted of 4-km walked transects to record indices of rabbit abundance. The percentage of vegetation cover and of different soil types were also estimated during these transects. In the same areas, the type and intensity of game management practices were obtained by interviewing hunting managers, hunters or gamekeepers. Rabbit populations were stable or increasing only in 26.6% of the studied populations, more commonly in areas with soft soils where warren building is easier for rabbits and where rabbits were an important game species and managed to increase their numbers. Although we could not establish causality, habitat management and predator removal were the main management practices related to rabbit population change. Rabbit scarcity in Spain constitutes a serious problem for conservation, so hunters, researchers and policy makers need to reach a consensus to establish a long-term program to monitor rabbit population trends and share results obtained, especially when intense manage programs are being carried out to improve rabbit abundance.

Feeding responses of the red fox (Vulpes vulpes) to different wild rabbit (Oryctolagus cuniculus) densities: a regional approach

We investigate the feeding responses of the red fox (Vulpes vulpes) at a regional scale to different densities of European wild rabbit (Oryctolagus cuniculus) in central- southern Spain. Rabbit abundance indices were obtained in 86 localities during summer 2002. The diet of the fox was studied by analysis of 114 scats collected in 47 of these localities. The feeding response of the fox was examined by a representation of the dry weight percent of rabbit in the diet as a function of the abundance of rabbits; this used data only from those localities where at least 3 scats were collected (70 fox scats from 18 localities). We evaluated the relationship between rabbit abundance and the diversity of the diet of the fox. The feeding patterns of red foxes approximated to Holling's type III functional response, typical of opportunistic predators. There was a negative relationship between the diversity of the fox's diet and the abundance of rabbits. Therefore, the fox apparently behaves as a facultative predator, feeding on rabbits when they are abundant and shifting to other prey (and hence a more diverse diet)

An experimental study of translocation success and habitat improvement in wild rabbits

AbstractThe translocation of wild animals is a strategy frequently used in the conservation and management of natural populations. The aim of this study was to evaluate the impact of translocation (population supplementation) and habitat improvement on the abundance of European wild rabbitOryctolagus cuniculus. We used eight open plots with different habitat treatments: two with increased shelter, two with increased food, two with increased shelter and food and two without habitat treatment (control plots). We translocated wild rabbits during 3 consecutive years, each year in four of the eight plots, with the remaining plots serving as control for the translocation treatment. Rabbit abundance (translocated plus native rabbits) was calculated by means of pellet counts, and the results were evaluated mainly by generalized linear mixed models. We found that rabbit abundance was determined primarily by habitat improvement. Rabbits were more abundant in treated than in control plots, and most abundant in the plots where food availability was increased. This effect persisted throughout the year. Translocation also increased abundance, but this effect was the strongest where shelter and food had also been improved and declined and disappeared after breeding. These findings suggest that the habitat is an important factor for rabbit abundance, with food availability being the prime factor regulating densities. Moreover, translocations on their own are only effective in the short term in situations in which factors limiting population growth (e.g. disease and predation) have not been corrected. Translocations should be carried out in conjunction with improvements in release habitat as rabbit densities will depend on the maximum carrying capacity of the habitat.

Mammals and agri‐environment schemes: hare haven or pest paradise?

Summary 1 Agri-environment schemes (AESs) are designed to create landscape-scale improvements in biodiversity. While the specific aims of AESs do not always include the enhancement of species of conservation concern, associated conservation strategies, such as the UK Biodiversity Action Plan, often rest on the assumption that AESs enhance environmental conditions and thereby improve the conservation status of target species. However, there is little evidence for the general efficacy of AESs in this respect. 2 To evaluate the effects of the Environmentally Sensitive Area (ESA) scheme, a widespread AES in Northern Ireland, a spotlight survey of the relative abundance of three mammal species, Irish hare Lepus timidus hibernicus, European rabbit Oryctolagus cuniculus and red fox Vulpes vulpes, was conducted. Of these, the Irish hare is a priority species for conservation action and the focus of a species action plan, while rabbit and fox are commonly considered agricultural pests. The effects of ESA designation and habitat on each species were assessed at 150 ESA and 50 non-ESA sites, matched for landscape characteristics. 3 The ESA scheme had no demonstrable effect on the abundance of Irish hares, and this agri-environment scheme did not target the landscape and habitat variables associated with hares. 4 In contrast, the abundance of rabbits and foxes was significantly greater within ESAs than the wider countryside. Agricultural factors such as reduced livestock stocking density, reduced overgrazing and field boundary enhancements may create more favourable conditions for both species. Aside from the implications for farm economics, the proliferation of rabbit populations within conservation areas may raise issues concerning the grazing of important plant communities, while increases in fox populations may adversely affect ground-nesting birds and other animal species of conservation concern. 5 Synthesis and applications. The abundance of rabbits and foxes corroborates recent work that suggests AESs may benefit common species but can not be relied upon to encourage rarer species. The Irish hare species action plan relies on agri-environment schemes to enhance the species’ status and realize the target of increasing the hare population by 2010 by promoting suitable habitat. However, the ESA scheme is unlikely to help in achieving these objectives. Targeted and evidence-based agri-environment prescriptions are clearly required in order to ensure the realization of species-specific conservation targets.

Increase of large game species in Mediterranean areas: Is the European wildcat ( Felis silvestris) facing a new threat?

There are several factors that threaten wildcat ( Felis silvestris) populations in Europe, including habitat destruction, direct persecution and genetic introgression from domestic cats. However, in contrast to other predatory species, lack of prey availability has not been evaluated as a risk factor for wildcats. In this study, we analyse the relationship between the abundance of wildcats and the abundance of their preferred prey, the wild rabbit ( Oryctolagus cuniculus), and the abundance of two large ungulates, the wild boar ( Sus scrofa) and red deer ( Cervus elaphus). The study was conducted in a typical Mediterranean ecosystem, the Monfragüe Natural Park (central Spain). We surveyed 30 (2 × 2 km) sites along a 2 km linear transect within each site, looking for signs indicating the presence of each species. Using this indirect method, we calculated an abundance index for each species based on their frequencies of occurrence. The results showed that the abundances of wild rabbits and ungulates were negatively associated. Moreover, wildcat abundance was positively related to rabbit abundance, but negatively related to ungulate abundances. Thus, the high population densities that ungulates reach in some natural areas, promoted in many cases by the hunting management strategies, appear to jeopardise wildcat populations by reducing rabbit availability. Therefore, as a new key action for the conservation of European wildcat we advocate the change of hunting management strategies in order to control ungulate populations, and therefore facilitate the recovery of wild rabbit populations.