Scrubland Habitats Research Articles

Home range, habitat use and capture-release of translocated leopards in Gir landscape, Gujarat, India.

Understanding the spatial ecology of translocated leopards (Panthera pardus fusca) is crucial for their conservation and the effective assessment of conflict management strategies. We investigated the home range and habitat preferences of five radio-collared leopards (n = 5; 2 males; 3 females) in the Gir landscape. Additionally, we examined the usefulness of the capture-release strategy for these animals. We assessed home range and habitat selection using kernel density estimation (at 95% and 50% levels) and compositional analysis. Our findings revealed that leopards exhibited distinct patterns of movement, often returning to their original capture site or nearby locations or exploring new areas within 3 to 25 days, covering distances ranging from 48 to 260 km. The average home range (95% FK) was estimated at 103.96±36.37 (SE) km2, with a core area usage (50% FK) of 21.38±5.95 km2. Seasonally, we observed the largest home ranges during summer and the smallest during winter. Males exhibited larger home ranges (95% FK, 151±64.28 km2) compared to females (56.18±14.22 km2). The habitat analysis indicated that agricultural areas were consistently preferred in the multi-use landscape at the 2nd order habitat selection level. Additionally, habitat around water bodies was highly favoured at the 3rd order, with distinct variations in habitat selection observed during day and night. This study highlights the significance of riverine and scrubland habitats, as leopards exhibited strong preferences for these habitats within their home ranges. We emphasize the importance of conserving natural habitat patches, particularly those surrounding water bodies. We also report on the characteristics of the capture-release strategy and provide our observations indicating no escalated aggression by leopards' post-release. In conclusion, this study evaluates widely employed approaches to conflict mitigation and suggests the continuous review and assessment of management strategies for mitigating human-leopard conflicts.

Landscape associations of Asiatic black bears in Kashmir Himalaya, Pakistan

The Asiatic black bear (Ursus thibetanus) is threatened throughout its range and assessed as nationally vulnerable in Pakistan. Habitat degradation and loss, illegal exploitation, and human–bear conflict are key threats to the species, but there is a lack of empirical knowledge regarding its occurrence in Pakistan. In 2012, we conducted a sign survey study to classify Asiatic black bear presence in a little studied and isolated region of the Kashmiri Mountains in Azad, Jammu and Kashmir, northern Pakistan. We compared bear presence in 5 habitat types (agriculture, forest, pasture, plantation, and scrubland) across an elevational range of 910 to 2,990 m. We used hierarchical logistic regression analysis to identify whether elevation, habitat and/or the interaction between the two explained bear presence in the region. Type of bear sign was significantly associated with some habitats, although claw marks were not associated with any habitat type. The strongest positive predictor of bear presence was the interaction between elevation and forest habitat, with greater presence (37.5%) in forest habitat at higher elevations between 1,890 and 2,855 m. The predicted likelihood of bears occurring in agriculture, plantation, and scrubland habitats was always <10%, regardless of elevation, and >30% in forest habitat. Our findings contribute to the national understanding of black bear presence and we provide recommendations for actions that support effective conservation management of the species in Pakistan.

Are insects declining and at what rate? An analysis of standardised, systematic catches of aphid and moth abundances across Great Britain

Although we have known anecdotally that insects have been declining in Great Britain for more than 100 years, insect declines have only been statistically estimated over the last 20 years. Estimation of the rate of those declines is still hotly debated, fuelled by a lack of standardised, systematically collected data.More than 24 million individual moths and aphids collected from 112 light traps and 25 12.2 m suction‐traps, respectively, were analysed using mixed models. Our objective was to estimate the long‐term trends in both groups based on annual totals recorded every year between 1969 and 2016.The models showed that two paradigms existed: Over 47 years, long‐term linear trends showed that moths had declined significantly by −31%, but short‐term trends indicated that there were periods of significant decline and recovery in most decades since the 1960s. Conversely, despite aphid annual totals fluctuating widely, this group was in a steady state over the long‐term, with a non‐significant decline of −7.6%. Sensitivity analysis revealed that moth trends were not driven by a group of abundant species, but the sign of the overall aphid trends may have been driven by three of the most abundant species.The spatial extent of moth trends suggests that they are extremely heterogeneous. Uniquely, moth declines were different among several habitat types, with robust significant declines found in coastal, urban and woodland habitats, but notably not in agricultural, parkland and scrubland habitats. Conversely, aphid trends showed spatial synchrony extending to 338 km, albeit with local variation.

Mapping Portuguese Natura 2000 sites in risk of biodiversity change caused by atmospheric nitrogen pollution.

In this paper, we assess and map the risk that atmospheric nitrogen (atN) pollution poses to biodiversity in Natura 2000 sites in mainland Portugal. We first review the ecological impacts of atN pollution on terrestrial ecosystems, focusing on the biodiversity of Natura 2000 sites. These nature protection sites, especially those located within the Mediterranean Basin, are under-characterized regarding the risk posed by atN pollution. We focus on ammonia (NH3) because this N form is mostly associated with agriculture, which co-occurs at or in the immediate vicinity of most areas of conservation interest in Portugal. We produce a risk map integrating NH3 emissions and the susceptibility of Natura 2000 sites to atN pollution, ranking habitat sensitivity to atN pollution using expert knowledge from a panel of Portuguese ecological and habitat experts. Peats, mires, bogs, and similar acidic and oligotrophic habitats within Natura 2000 sites (most located in the northern mountains) were assessed to have the highest relative risk of biodiversity change due to atN pollution, whereas Natura 2000 sites in the Atlantic and Mediterranean climate zone (coastal, tidal, and scrubland habitats) were deemed the least sensitive. Overall, results allowed us to rank all Natura 2000 sites in mainland Portugal in order of evaluated risk posed by atN pollution. The approach is of great relevance for stakeholders in different countries to help prioritize site protection and to define research priorities. This is especially relevant in countries with a lack of expertise to assess the impacts of nitrogen on biodiversity and can represent an important step up from current knowledge in such countries.

Diurnal activity patterns of Harwood’s Spurfowl Pternistis harwoodi in relation to habitat types and climatic conditions in the Central Highlands of Ethiopia

Harwood’s Spurfowl Pternistis harwoodi is an endemic bird of Ethiopia. Globally, it is categorised as Vulnerable. Habitat loss and hunting are the major conservation threats to the species. This study investigated the activity patterns of Harwood’s Spurfowl in relation to biophysical variables in the Central Highlands of Ethiopia. A species focal sampling method was applied to quantify the time budget of the target species during the dry and wet seasons of 2016. The time spent by the species on various activity patterns were significantly different (p < 0.05). The mean proportion of time utilised by the species for ‘calling’, ‘feeding’, ‘preening’ and ‘resting’ activities based on habitat types and seasons were also statistically different (p < 0.05). Except for ‘resting’, most activity patterns showed bimodal patterns with peaks during the early morning and late in the afternoon. The number of Harwood’s Spurfowl (birds per hour per square metre) detected was higher during the cooler wet season. The highest bird counts occurred during low temperature, low wind speed and high relative humidity in the early morning and late afternoon. The species was recorded most in the scrubland habitat where human disturbance was low. Thus, this habitat should be conserved and managed to sustain the population.

Macro- and micro-habitat selection of small rodents and their predation risk perception under a novel invasive predator at the southern end of the Americas

Invasive predators are responsible for the extinction of numerous island species worldwide. The naive prey hypothesis suggests that the lack of co-evolutionary history between native prey and introduced predators results in the absence of behavioral responses to avoid predation. The lack of terrestrial mammal predators is a core feature of islands at the southern end of the Americas. Recently, however, the American mink (Neovison vison) established as a novel terrestrial predator, where rodents became a main portion of its diet. Here, we investigated on Navarino Island, Chile, macro- and micro-habitat selection of small rodents using Sherman traps. Additionally, we experimentally tested behavioral responses of small rodents to indirect cues of native raptorial predation risk (vegetation cover) and direct cues of novel mink predation risk (gland odor) using Sherman traps and foraging trays (giving-up density (GUD)). At the macro-habitat level, we detected native rodents of the species Abrothrix xanthorhinus and Oligoryzomys longicaudatus and the exotic Mus musculus. In general, rodents preferred scrubland habitats. At the micro-habitat level, we only captured individuals of A. xanthorhinus. They preferred covered habitats with tall vegetation. GUD increased in opened areas (riskier for raptorial predation) regardless of the presence or not of mink odor. These results suggest that A. xanthorhinus can perceive predation risk by raptors, but not by mink, results that accord with the hypothesis that co-evolutionary history is important for rodents to develop antipredator behavior. Given that these rodents represent an important proportion of mink diet, the low abundances together with the apparent lack of antipredator response raise conservation concerns for the small rodent populations inhabiting the southernmost island ecosystems of the Americas.

Landscape degradation affects red fox (Vulpes vulpes) diet and its ecosystem services in the threatened Ziziphus lotus scrubland habitats of semiarid Spain

Habitat loss and landscape degradation affect carnivorous mammal populations and the ecosystem services they provide, but these services are poorly assessed in semi-arid ecosystems. In the Ziziphus semiarid scrublands, a priority habitat for conservation in Europe, we investigated how red fox diet relates to habitat loss and landscape alteration. We further evaluated potential top-down effects of foxes on vegetation through seed dispersal and the control of rabbit herbivory (fruit depulpation interfering seed dispersal). By sampling fox scats, we evaluated the variation in fox diet and its relationship to landscape features and rabbit abundance and activity in 17 habitat remnants distributed throughout the Ziziphus habitat range. Fox diet varied, with diet diversity peaking at intermediate land-use diversity, likely as a consequence of fox's ability to use natural foods and human-derived resources. We confirmed that red fox acts as seed disperser for many species and that it might contribute to control rabbit population and its impact on Ziziphus lotus regeneration by interference on seed dispersal, though this needs experimental corroboration. However, these services were affected by landscape degradation. Our results show that red fox is fundamental for Ziziphus semiarid ecosystem providing key ecosystem services which are presently jeopardized by strong landscape degradation.

Germination patterns of the scrublands in response to smoke: The role of functional groups and the effect of smoke treatment method

Smoke is thought to be one of the most important fire cues stimulating seed germination of species from both fire-prone and fire-free ecosystems. The impact of smoke on seed germination at the community level of certain habitats in Western Asia has not been investigated yet. We aimed to analyze the effects of different smoke treatments on soil seed germination of different plant functional groups in a scrubland habitat. A soil seed bank was used to count seedling emergence following aerosol smoke (15min or 30min exposure) or smoke-water (1:1000 and 1:500, v/v) treatment. Smoke-induced germination was then separated into five functional groups (i.e. annual grasses, perennial grasses, annual herbs, perennial herbs, and legumes). The results showed that seeds of annuals were stimulated with smoke. In contrast, germination of perennial grasses was reduced by the smoke treatments, whereas perennial forbs and legumes showed no particular response to the smoke treatments. The longer exposure time to the aerosol smoke (30min) and the higher concentration of smoke-water (1:500, v/v) were not at detrimental levels and resulted in maximum germination among the functional groups, other than perennial grasses. Our results indicate that smoke-stimulated germination of annuals plays an important role in species establishment after fire in the scrublands of Western Asia. Smoke treatments impacted differently on the different functional groups, and it is useful to determine the smoke response-classifications of these species to understand the effects of fires on the plant communities.

Avifaunal diversity of Manjeera Wildlife Sanctuary, Andhra Pradesh, India

A total of 164 bird species belonging to 53 families were recorded in the Manjeera Wildlife Sanctuary. Of these 107 species were resident, 55 species were winter migrants and 2 species were summer migrants. The population of the each species in different habitats was estimated. Species richness was observed to be more in agriculture habitat followed by scrubland, grassland and marshy areas, whereas species diversity was observed to be more in scrubland habitat followed by agriculture lands, grasslands and marshy areas. Similarity Index analysis showed that the habitats of agriculture land-scrubland are more similar whereas, habitats of scrubland-marshy area show dissimilarity in the sanctuary.

Individual variation in the contact calls of the monomorphic Peach-fronted Conure, Aratinga aurea, and its potential role in communication

In several avian and mammal social species, contact calls are hypothesized to function in maintaining group cohesion, coordinating activities between group members and negotiating fissions and fusions of multiple groups during foraging and roosting. They are therefore expected to exhibit acoustic features that make them suitable for communication of identity information. We investigated this in the monomorphic Peach-fronted Conure, a tropical parakeet living in open forest and scrubland habitats. The species is highly social outside the breeding season where it is assumed to live in a fission–fusion social system. In this study, contact calls from 10 visually isolated male and female Peach-fronted Conures were recorded outside the breeding season. Results from the multivariate analysis of variance and spectrographic cross-correlation with principal coordinates analysis procedure showed that contact calls varied highly between individuals and indicated that caller identity could be encoded in the duration, peak frequency, max frequency and 25%, 50% and 75% frequency energy quartiles of contact calls. The 50% frequency and 75% energy quartile was also significantly higher for females than for males. Furthermore, the results showed an inverse relationship between two morphometric measures and two spectral parameters, suggesting that variation in call parameters could also allow receivers to obtain information about the body size of the caller. Discriminant function analysis showed that contact calls could be correctly classified to individuals in 100% and to sexes in 91% of the cases, suggesting that there is sufficient variation in contact call parameters to enable vocal recognition of individuals and sex.

Change in demographic patterns of the Doñana Iberian lynxLynx pardinus: management implications and conservation perspectives

AbstractOver the last 20 years surveys of the population of the Iberian lynxLynx pardinusin Doñana National Park and its surroundings in Spain have produced estimates of a total population of 50–60 in fragmented patches. The population was estimated to be 26 adults in 2002–2003. Use of camera trapping and other field methods during 2004–2008 allowed us to determine the abundance of the lynx and to estimate demographic statistics. Estimated annual abundance of adult and subadult lynxes averaged 38 individuals (range 35–43). Although the population exhibited a continuous distribution it was concentrated in three major areas, including Doñana National Park, with an average area occupied of 620 km2. Our results suggest that the Doñana Iberian lynx population now has a different structure from that in the 1990s and in particular a more continuous spatial distribution. These results indicate an improved, but not secure, scenario for the population. The continuous geographical distribution suggests the population is currently less vulnerable to extinction than 10 years ago. Conservation actions now need to focus outside Doñana National Park on the reconversion of pine plantations into original Mediterranean scrubland habitat, and the continuity and intensification of ongoing restocking with rabbits in fenced areas.

Territory Distribution and Habitat Selection of the Serra Finch (Embernagra longicauda) in Serra Do Cipó, Brazil

Abstract The near-threatened Serra Finch (Embernagra longicauda) is restricted to the main mountain ranges in eastern Brazil inhabiting campos rupestres (rocky fields). We mapped 17 mated pairs in a 138-ha area within Serra do Cipo National Park; a density of 0.25 adults/ha. Estimated average territory size varied from 2.52 ± 0.77 ha (95% kernel) to 3.35 ± 0.90 ha (100% minimum convex polygon). The distance between territory centers of neighboring pairs was 162.38 ± 28.93 m. The overlap between neighboring territories was 15.3 ± 5.9% (95% kernel) and 2.0 ± 2.3% (polygon method). Pairs remained together throughout the year in the same territories and defended these against intruding neighbors. Analyses of habitat selection indicated preference for woodland and scrubland habitats associated with humid valleys, while grasslands were avoided. The Serra Finch used the available habitats more than expected from random at different spatial scales. Our data identified habitats that should be priority for conserva...

Population Demographics and Dynamics of Colonizing Elk in a Desert Grassland–Scrubland

AbstractElk Cervus elaphus are rare in Southwestern desert grassland and desert-scrub habitats, and these habitats are anecdotally considered unsuitable for elk. We studied a colonizing herd in a Southwestern desert grassland–scrubland in northwestern New Mexico to determine the condition and population dynamics of elk in this habitat type. We radiotracked ≤ 24 adult (1.5 y and older) cows and ≤ 8 calves annually, 2003–2006; the sample of radiocollared cows in this study was very close to a census of the entire population for 2004–2006 based on repeated surveys and monitoring. Mean body fat of lactating cows in autumn was 10.6–13.2% in 2003–2004, indicating that lactating elk were acquiring high moderate–low good nutrition, but dropped to 5.6% in 2005 and 6.8% in 2006, indicating poor nutrition for these years of low precipitation. We found adult female survival of 0.94–1.00 and calf survival of 0.38–1.00. Calf survival was related to maternal size, maternal condition, and cumulative annual precipitation through parturition; all calf mortality occurred at or near parturition. Pregnancy rates averaged 0.33 for yearling cows and 0.86 for ≥ 2.5-y-olds, 2003–2006, and pregnancy was positively related to body mass for ≥ 2.5-y-old adults. Lactation rates of ≥ 2.5-y-olds averaged 0.59, 2003–2005, but dropped to 0.30 in 2006, due to poor maternal condition and low precipitation. Since colonization, elk have increased from about 20 to ≥ 53 individuals, a mean rate of increase of 18%/y prior to 2006, but decreasing to ≤ 4% in 2006. The high sustained rate of increase (with few exceptions) indicates that desert grassland–scrubland habitats are suitable for elk and merit consideration in elk management plans of Southwestern agencies.

Risk analysis of potential invasive plants in Spain

Once non-native species become established in a new region, they are extremely difficult to eradicate or control, suggesting an urgent need for the development of early warning systems to determine the probability of a given species becoming invasive. Risk assessment schemes are valuable tools to diminish the risk of invasion and to concentrate resources on preventing the entrance and spread of those species with higher risk of invasion. For many European countries, plant species not yet introduced to the country and with high invasive potential have not been identified. The present study aims to identify and rank non-native plant species that could potentially become invasive in Spain if introduced. As a first step, a plant data set was pre-selected for screening, containing invasive plants in neighbouring countries and in other Mediterranean regions of the world but not present in Spain. A preliminary list of 80 species was obtained, Leguminosae being the most represented family (15%) and gardening (62%) the most common pathway of introduction. As for the potential European Nature Information System (EUNIS) habitats to invade, heath land and scrubland habitats types (F; 19%), followed by constructed, industrial and artificial habitats (J; 14%) and woodland and forest habitats (G; 13%) seem to be the habitats most at risk despite F and G habitats currently being the least invaded in Spain. We ranked these potential invasive species using the Australian Weed Risk Assessment system and a Risk Assessment for Central Europe developed by Weber & Gut (2004) [Weber, E., & Gut, D. (2004). Assessing the risk of potentially invasive plant species in central Europe. Journal for Nature Conservation , 12, 171–179]. Most species received intermediate values in both tests. The species with higher scores were mainly aquatic plants and should be prohibited or kept out of trade. Chromolaena odorata (Asteraceae) obtained the highest score in both tests and therefore is the species with the highest risk to become invasive in Spain if introduced.

Change your diet or die: predator-induced shifts in insectivorous lizard feeding ecology

Animal feeding ecology and diet are influenced by the fear of predation. While the mechanistic bases for such changes are well understood, technical difficulties often prevent testing how these mechanisms interact to affect a mesopredator's diet in natural environments. Here, we compared the insectivorous lizard Acanthodactylus beershebensis' feeding ecology and diet between high- and low-risk environments, using focal observations, intensive trapping effort and fecal pellet analysis. To create spatial variation in predation risk, we planted "artificial trees" in a scrubland habitat that lacks natural perches, allowing avian predators to hunt for lizards in patches that were previously unavailable to them. Lizards in elevated-risk environments became less mobile but did not change their microhabitat use or temporal activity. These lizards changed their diet, consuming smaller prey and less plant material. We suggest that diet shifts were mainly because lizards from risky environments consumed prey items that required shorter handling time.

Competition for food between the exotic wasp Vespula germanica and the native ant assemblage of NW Patagonia: evidence of biotic resistance?

The success of a biological invasion may depend on the interactions between the invader and the native biota. However, little experimental evidence demonstrates whether local species can successfully compete with exotics. We experimentally determined the existence of competition for food between the exotic wasp Vespula germanica, one of the most recent Patagonian invaders, and the native ant assemblage. Both wasps and ants are generalist predators and scavengers, sharing habitat and food resources. We selected 30 sites within scrubland habitats where both ants and wasps were present. At each site, we placed containers with protein baits under three treatments: wasp exclusion, ant exclusion, and control (i.e., free access for wasps and ants). Ant exclusion increased the number of wasps (with regard to a control), but wasp exclusion did not affect ant abundance. This result suggests that native ants affect the foraging activity of exotic wasps but not vice versa. Aggressive behaviors and worker aggregation may explain the competitive advantage of ants. Ants bite wasp legs and massively aggregate on food sources, physically limiting the landing of wasps on baits. If the outcome of interactions at baits reported here influence wasp population-level parameters, this competitive interaction could be one of the factors explaining the low abundance of this exotic wasp in NW Patagonia in comparison with other invaded regions.

The priority value of scrubland habitats for carnivore conservation in Mediterranean ecosystems

Carnivores are umbrella species with a key role in ecosystems. In the Mediterranean, they face with several conservation problems, mainly habitat loss or transformation. In this region, scrubland habitats are considered of minor conservation relevance as compared to mature forest formations. Conservation of scrublands in Mediterranean ecosystems is also difficult because to control fires, they are removed over large areas. For carnivores, scrublands may be essential to guarantee shelter and food. Here, we analyzed the importance of scrublands and other habitat variables in determining the richness of medium-sized carnivores in a typical Mediterranean area of central Spain (Monfrague Natural Park). The Park was divided into plots of 2 × 2 km (n = 30). In each plot, a 2 km-length survey route was walked searching for carnivore scats. We recorded the number of species of carnivores and we related this value to several habitat variables. Habitat variables were summarized by means of Principal Component Analysis (PCA). Habitat models were developed by, using multiple regression models, including PCA factors and the habitat type as predictors. The only variable included in the final model was the first PCA factor. Carnivore richness was positively associated with large tree, shrub, and rock cover areas, which is the typical habitat structure of scrublands. This habitat offers the best available area for shelter and may be considered as a key element for carnivore conservation in the Mediterranean region. To reconciliate carnivore conservation and forestry management, we proposed small-scale clearances as a management alternative to typical large scrubland removals.

Diet, habitat use, and relative abundance of pampas fox ( Pseudalopex gymnocercus) in northern Patagonia, Argentina

Diet, habitat use and relative abundance of pampas fox Pseudalopex gymnocercus were studied in grassland, sand dune, and scrubland habitats, on the Bahía San Blas and Isla Gama Reserve, Argentina. Scat contents showed a generalist diet, where mammals, insects, and fruits were the main food items. Dietary composition differed among habitats; fruits were mainly consumed in sand dunes; insects, mammals, and fruits predominated in grassland; while insects and mammals were frequent in scrubland habitat. The European hare was the most common vertebrate prey and had the major contribution to the biomass of consumed prey. Pampas fox was the most common carnivore of the reserve and used all available habitats, frequenting more regularly scrubland and sand dune than grassland habitat.

Winter bird communities in the northern Negev: species dispersal patterns, habitat use and implications for habitat conservation

Bird habitat conservation may require different management strategies for different seasonal bird assemblages. We studied habitat use by winter birds in forest and scrubland habitat patches in the northern Negev, Israel. Our goal was to assess whether differences in responses to landscape and habitat structure between breeding and non-breeding seasons require changes in future conservation plans that have been suggested for the Negev breeding bird community. We evaluated habitat and area effects on bird abundance and distribution and tested whether species habitat use during winter involves niche shifts. Compared with breeding birds, a larger proportion of winter bird species occupied both scrubland and forest. As in summer, forest bird species responded to habitat structure, whereas scrubland species were associated with both habitat structure and area. Resident birds disperse into habitats in which they were not present during summer. Consequently, for several species, the correlation between bird densities and environmental factors showed a better fit at the landscape rather than at the habitat scale. In addition, rather than niche shift, birds actually extended their niche breadth. Nest site selection may constrain bird distribution into a realized niche, smaller than their fundamental niche. Despite the scale differences in habitat use, the similar species diversity patterns between seasons suggest that both winter and summer birds would benefit from conservation of scrub patches larger than 50 ha, and enrichment of foliage layers within the planted forests.

The negative impact of heavy rains on the abundance of a Mediterranean population of European rabbits

European rabbits, Oryctolagus cuniculus, are the basic prey of several endangered predators and an important hunting bag in the area of its origin in southwestern Europe. Conversely, they are considered an undesirable species in other areas where they were introduced. Therefore, there is great interest in understanding the factors that influence population dynamics and abundance of this species. I studied the effects of relatively common heavy rains on inter-annual variations in rabbit density in four habitats of Donana National Park and surrounding areas (southwestern Spain) during several years when rainfall was either lower or higher than average. I estimated spring and autumn rabbit densities by line transect sampling between autumn 1993 and autumn 1998, and counted rabbit warrens and entrances in two of the habitats (one with and the other without scrubland vegetation) in 1995, 1996 and 1997. Rabbit density significantly decreased in all habitats during the rainy years, densities being on average 5.3 and 4.6 times lower for spring and autumn censuses, respectively. Both number of warrens and entrances significantly decreased after two consecutive years of heavy rain in both habitat types, although in the scrubland habitats some recovery was observed during the second consecutive year of heavy rains. The area where warrens were apparently free of the effects of rains was only between 2.7 and 3.8% in the open habitat and 21.5% in the scrubland. At least for the open habitat, no clear relationship was observed between the height above sea level and whether warrens were affected by rain or not. The results indicate that heavy rains may be an important factor decreasing rabbit density, at least in flat areas, by negatively acting on warrens during the breeding period.