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Conservation of brown bear in the Alps: Space use and settlement behavior of reintroduced bears
Abstract
Large carnivores typically need large home ranges containing habitats patches of different quality. Consequently, their conservation requires habitat protection and management at the landscape scale. In some cases. reintroduction might be used to support remnant or restore extinct populations. This is the case for the brown bear (Ursus arctos) in the Italian Alps. We monitored spacing behavior and settlement of reintroduced brown bears in Adamello-Brenta Natural Park, North-Italy, using radio-tracking. Habitat use, dispersion and survival were studied to evaluate the success of reintroduction and possible conflicts with man. All three males and five of seven females settled in the study area. Most bears roamed widely the first months after release, exploring the new habitat. Patterns of home range overlap between seasons and years revealed that home range use stabilized the year after first hibernation. Home ranges were larger in the mating season (May-July) than in spring or autumn. Home ranges varied between 34 and 1813 km(2) the year after release. but core-areas. where feeding activity was concentrated, were much smaller. Some bears had exclusive core-areas in summer and autumn, but most showed considerable core-area overlap with animals of the same and/or the opposite sex. Bears selected deciduous forests, mixed and conifer forests were used according to availability, and areas with anthropogenic disturbance were avoided. Most bears settled and some reproduced successfully at the release site, causing high initial population growth, suggesting that reintroduction call help to re-establish a brown bear Population in the Italian Alps. (c) 2005 Elsevier SAS. All rights reserved.
... In Europe, successful context-specific management strategies have played a pivotal role in the partial recovery of large carnivores during the past decades (Chapron et al. 2014), and findings assessed through GPS-based studies have often represented a solid basis to inform large carnivores' management worldwide (Preatoni et al. 2005;Chetkiewicz and Boyce 2009;Latham et al. 2011;May et al. 2012;Peters et al. 2015;Pop et al. 2018). However, in some regions of Europe, quantitative studies investigating large carnivores' habitat selection are still lacking. ...
... Habitat selection of brown bears has been thoroughly studied in the wild areas of North America (McLellan and Hovey 2001;Nielsen et al. 2002;Ciarniello et al. 2007;Chetkiewicz and Boyce 2009) and Scandinavia (Moe et al. 2007;Nellemann et al. 2007;Martin et al. 2010;Elfström et al. 2014a). Research on habitat selection has been also conducted for brown bears of the Carpatian (Fernández et al. 2012;Ziółkowska et al. 2016b;Pop et al. 2018), Cantabrian (Clevenger et al. 1990Mateo Sánchez et al. 2013;Mateo-Sanchez et al. 2016), Pyrenean (Martin et al. 2012), Eastern Italian Alps (Preatoni et al. 2005;Peters et al. 2015) and Appennine (Falcucci et al. 2009) ...
... In the attempt to capture landscape heterogeneity, we used an ensemble of GIS layers to describe topography, land cover and human infrastructures. We created predictors to be included in seasonal additive full models based on their biological meaningfulness and interpretability, as emerged from previous literature on brown bear habitat selection (Preatoni et al. 2005;Nellemann et al. 2007;May et al. 2008;Chetkiewicz and Boyce 2009;Martin et al. 2010;Milakovic et al. 2012) Topography layers included elevation, ruggedness and slope layers. We derived binary (1-0) land cover layers from Corine Land Cover (CLC) 2012 with a resolution of 100m. ...
Space is one of the most disputed resources between humans and other wildlife species in modern human-dominated landscapes. Successful wildlife management and conservation requires a deep understanding of the interactions between a species and the space where it lives, including direct and indirect effects of both natural and human-related factors of fundamental ecological processes. The high spatio-temporal resolution of Global Positioning System (GPS) tracking data turns tagged animals into in situ sensors of the environment, and allows investigating how environmental changes affect species’ distribution and ecological function. Large carnivores, in particular, with their wide movement ranges and large spatial requirements are highly susceptible to disturbance from infrastructure development; as such, they can represent an ideal case study to investigate the effects of expansion of human activities on species’ spatial ecology at multiple levels, spanning from patch to landscape scales.
In this thesis, I investigated space-use patterns of a south-eastern European population of brown bears (Ursus arctos), whose distribution is shared among more than five countries, from Slovenia to Northern Greece, with its core between Slovenia and Croatia. Despite being the third largest brown bear population in Europe, only few studies have focussed on the spatial ecology of the Dinaric-Pindos bear population. I investigated how environmental factors and proxies of human activities (e.g., roads, human settlements, hunting sites) influenced patterns of bear space use, movements and habitat selection. I used this knowledge to develop a movement-based modelling approach, aimed at mapping patch connectivity for seasonal movements of bears within the study area. In addition to enhancing our knowledge of bear ecology at broader scale across Europe, the results from this thesis are also of practical value, as they inform current and future management and conservation scenarios in the light of ongoing development projects throughout the countries inhabited by the study population.
... With its dense infrastructure the Adige Valley effectively divides the study area into two sections, representing the biggest obstacle to habitat connectivity for several mammal populations. The bear reintroduction area included submontane, montane and subalpine vegetation communities (Preatoni et al., 2005). The vegetation composition ranges from mixed deciduous vegetation of mainly common beech (Fagus sylvatica) mixed with European larch (Larix decidua) and pine (Pinus spp.) to subalpine forest communities composed of pine and spruce (Picea spp). ...
... To avoid potential effects of reintroduction on resource selection, such as exploratory movements, we excluded data before the formation of a home-range (around 6 months, usually after first denning season). VHF collared bears were triangulated from the ground twice daily (see Preatoni et al., 2005). All of the six GPS collared bears were initially radio collared because they were 'conflict' bears, that is, they used or damaged human property or were perceived as threat. ...
... The GPS-collared bears were captured either via free range darting, Aldrich snares or culvert traps (Groff et al., 2013) upon approved capture protocols (2003-DPR 357/97). For more details about the capture and reintroduction, see Mustoni et al. (2003) and Preatoni et al. (2005). GPS collars collected positions at different intervals ranging from 10 min to 1 h, which we re-sampled to a consistent 2-hour relocation schedule. ...
Large carnivores are declining worldwide and few examples of successful reintroductions exist, because of their large home-ranges, low reproductive rates, and penchant for human–wildlife conflict that is the main cause of their decline. Moreover, few studies assess whether habitat suitability predicted before reintroduction, a critical evaluation step, matches post-reintroduction habitat selection. We examined habitat-related factors contributing to a successful brown bear (Ursus arctos) reintroduction in central Europe. Starting in 1999, 10 brown bears were translocated from Slovenia to Trentino in the Italian Alps, and this population has since grown by >10%/year. First, we estimated multi-scale resource selection functions (RSF) with GPS collar data and validated models with k-folds cross validation and external VHF data. Then, we used Kappa-statistics to compare our population-scale RSF with a habitat suitability model (HSM) developed to predict potential habitat before reintroduction. Lastly, we employed least-cost path (LCP) analyses integrating our within home-range scale RSF to define movement paths. Overall, the HSM predicted post-reintroduction habitat selection well in many areas, but bears used orchards and shrubs more, and mixed/conifer forests and pastures less than expected prior to reintroduction. Finally, we identified road crossings of predicted paths between preferred habitat patches. We found two potential crossings in the Adige Valley, likely the biggest constraint for the study population to expand eastward and impeding dispersal to/from the closest bear population (Dinaric–Pindos population). Increasing awareness for key brown bear habitats and corridors, especially in potential ecological traps within cultural landscapes, will be necessary for large carnivore conservation.
... Bears are known to react to both human activity (e.g., Clevenger et al. 1992, Nellemann et al. 2007, May et al. 2008) and environmental conditions (Slobodyan 1974, Swenson et al. 2000, and we assumed based on their large range size (Preatoni et al. 2005) that they are sensitive to multiple spatial scales. Therefore, to investigate which combination of variables best explained bear activity in woodpastures, we grouped our explanatory variables as follows: (1) anthropogenic variables (AV), (2) local variables (LV), and (3) variables describing the (broader) landscape context (LC). ...
... Bear activity in wood pastures was primarily driven by environmental variables at the landscape level and to a lesser extent by anthropogenic variables. The importance of the landscape variables is consistent with previous studies, which also identified mountainous regions (Posillico et al. 2004), as well as rugged and forested areas, as being preferred by bears for shelter, denning sites, and food (Clevenger et al. 1992, Preatoni et al. 2005, Nellemann et al. 2007, May et al. 2008. The relative lack of importance of local variables was surprising because we hypothesized that distance to the forest edge could be an important element of escape cover (Swenson et al. 2000) and expected higher bear activity closer to forests. ...
... Bear occurrence has been shown to be negatively affected by human presence (Clevenger et al. 1992, Preatoni et al. 2005, Nellemann et al. 2007, May et al. 2008. However, bear activity in our study was Table 2. Best-supported model describing which variables explained bear activity in wood-pastures, Southern Transylvania, Romania, in 2012. ...
During the past century, habitat fragmentation and increased human impacts have
reduced populations of large carnivores throughout the world. Although bears have been
extirpated from human-dominated landscape in most parts of Europe, they still occur in multiuse
cultural landscapes in Southern Transylvania, Romania. Wood-pastures—grazed permanent
grasslands with scattered or clumped trees and shrubs—are important elements of these
cultural landscapes and provide habitat for a wide range of species. However, wood-pastures are
under threat from land-use change, including intensified agricultural use and land
abandonment. In 2012 we assessed the level of activity of brown bears (Ursus arctos) and
environmental factors influencing bear activity in 54 wood-pastures in Southern Transylvania.
As an index of bear activity, we measured the proportion of anthills that were destroyed by
bears. The variables were combined in 3 groups (anthropogenic effects, local variables, and
landscape context) to test which group most strongly influenced bear activity. Bear activity was
found in 47 (87%) wood-pastures. Bear activity was best explained by variables describing the
landscape context, with proximity to the Carpathian Mountains, terrain ruggedness, and
amount of surrounding woody vegetation positively related to bear activity. Local variables
(distance to forest edge and anthill density) had no effect, and surprisingly, variables related to
anthropogenic features (distance to major roads, distance to villages) were positively related to
bear activity (albeit weakly). Most of the wood-pastures in Southern Transylvania were used by
bears for foraging on ant larvae. For the conservation of brown bears in Southern Transylvania,
it is important to maintain large areas of forest but also consider cultural landscape elements
such as wood-pastures. To conserve European wood-pastures, we suggest they be explicitly
considered in national nature conservation policies and in major European Union (EU) policies
such as the EU Habitats Directive.
... EMMA 2011) and the size of individual bear ranges in the Balkans, Apennines and Alps (Kaczensky et al., 2003;Posillico et al., 2004;Preatoni et al., 2005). ...
... Observations on bear presence include sightings, but most records represent signs of presence. The number of each observation type in the corrected set of records used in SDM was assessed for observational bias inherent in exclusive day-time sightings of a nocturnal species (Kaczensky et al., 2006) or single-sign records (Preatoni et al., 2005). ...
... The output grid size (800 m) was selected for spatial consistency with SDM. The optimal circular search radius (Preatoni et al., 2005) for the density tool was generated using the likelihood crossvalidation method (Horne & Garton, 2006;Animal Space Use, 2009;Pittiglio et al., 2012). The resulting densities were compressed using natural breaks in three classes. ...
The Brown bear (Ursus arctos Linnaeus, 1758) occupies contiguous areas in Eastern and Northern Europe. In Western Europe, the largest remnant populations occur in Cantabria, Spain and the Apennines, Italy. Under Italian law the bear and its occupied range are protected. The occupied range of the Apennine brown bear includes Majella National Park. However, information on the distribution within Majella NP is extrapolated and inconsistent, thus precluding evidence-based protected area and species management. To address this lack of information, bear presence records (1996–2010) were collated and corrected for observational bias. Multiple Species Distribution Models (SDMs) were created at 800 m resolution to predict year-round and seasonal bear distribution. A hierarchical, stepwise maxent SDM approach was applied using climatic, terrain, vegetation, and anthropogenic predictors of bear distribution. Occupied ranges were identified by point density analysis of bear presence. Our climate-only SDMs predicted bear presence in areas with relatively low snowfall and temperate temperatures. Year-round bear distribution was also accurately predicted by using temperate-montane elevations and mesic, mesotrophic vegetation substrates, irrespective of vegetation. Ski-resorts were negative predictors of year-round bear occurrence. Bears were predicted in autumn and winter by beech forest, in spring by meadows and in summer by a variety of vegetation categories. The regional and our local models predicted bear throughout the south. However, our predicted and occupied range in the north includes the Orta valley and exclude alpine heights, contrary to the regional models. Only our summer bear range is similar to a regional SDM. We demonstrated that multiple maxent SDMs using a modest number of observations and a comprehensive set of environmental variables may generate essential distributional information for protected area and species management where full wildlife and food source censuses are lacking.
... (1) Individuals are primarily restricted to forest-dominated areas where they find nutritional and refuge resources required for maintenance, hibernation and reproduction (Naves et al., 2003;Posillico et al., 2004;Katajisto, 2006). Moreover, forest composition is a key determinant of habitat quality due to the high nutritional requirements of the species, its dependence on hard and soft mast during hyperphagia and the need for alternative food resources throughout the year (Preatoni et al., 2005;Moe et al., 2007). ...
... The human influence hypothesis was clearly supported, especially the influence of urban settlements, whereas the effect of forest composition factors on the species occurrence was less obvious. Habitat use in other European populations is characterized by a clear avoidance of human settlements, infrastructures and disseminated recreational resorts (Clevenger et al., 1997;Preatoni et al., 2005;Nellemann et al., 2007;Martin et al., 2010). Bears may adjust their seasonal and daily use of the habitat according to their perceived risk in relation to human settlements, e.g. ...
... Habitat factors associated to the distribution and availability of natural resources (forest composition and topographic variables) were not selected in the most parsimonious model. Previous studies have found a higher proportion of deciduous forests and terrain ruggedness in bear habitats linking their effects to mast production and to the availability of heterogeneous nutritional resources, respectively (Naves et al., 2003;Preatoni et al., 2005). Although deciduous forests were also more abundant in bear occurrence areas in the Carpathians, their influence was not supported when the confounding effects of the total forest coverage were separated. ...
a b s t r a c t The utility of habitat models for species conservation relies on the integration of ecological knowledge into the modeling process. However, this practice is often limited by incomplete information on the study species requirements and insufficient efforts to adopt robust inference modeling approaches. We devel-oped occurrence and breeding habitat models for the European brown bear Ursus arctos in the Northern range of the poorly-known Carpathian population, focusing on the evaluation of a restricted set of hypotheses based on prevailing insights on the species constrains. Hypotheses were confronted using a dataset of 3151 bear observations in Poland for the period 1985–2005. Forest availability was the most important limiting factor, whereas anthropic factors (human density and urban areas) separated between suitable and non-suitable forest-rich areas. Forest composition contributed poorly to predict bear occur-rence but was important to differentiate between breeding and non-breeding habitats: breeding females required a larger amount of forest cover, lower human influence and the interspersion of grassland/ shrubland patches. Model transfer to the western Carpathian population in Slovakia supported the accu-racy of habitat predictions and the robustness of the approach. Results highlight the need to control unplanned urban sprawl to preserve the species habitat and the connectivity between the Western and Eastern segments of the Carpathian population. Predicted but unoccupied habitats in other regions also require consideration, particularly some favorable areas of confluence with other large carnivore habitats. We encourage adopting robust hypothesis testing approaches in habitat modeling in order to support better model transferability and conservation planning.
... This study presents the first extensive assessment of space use and movements for brown bears in the Romanian Carpathians. Our results show larger home range size in Romania compared to bears in Bulgaria (MCP100% and Kernel 99% isopleth for home ranges and Kernel 50% isopleth for core areas, Gavrilov et al. 2015) and Sweden (MCP95%, Dahle et al. 2006) and comparable to those reported in Italy (MCP100% and Kernel 95% isopleth for home ranges and Kernel 50% isopleths for core areas, Preatoni et al. 2005). The larger home range sizes from our study could be due to external factors such as human disturbances due to logging activities, heterogeneous landscapes or food availability. ...
... As the main limitation of the study was related to the small numbers of bear females (4) and subadults (5), some of our results should therefore be interpreted with caution (Preatoni et al. 2005). Using a larger dataset and considering the seasonal and altitudinal gradient of the food availability (Roellig et al. 2014), may result in differences between seasonal movements and/or between genders. ...
Brown bear movement patterns are driven by their opportunistic feeding behaviour, with their complex life history and seasonality playing an important role in habitat selection. Within a large unfragmented forest habitats persisting over decades in the Romanian Carpathians and a prohibitive hunting management during 40 years of communist centralised game management, information about brown bear movements and spatial ecology is lacking. Using data obtained from 13 brown bears fitted with GPS telemetry collars, we estimated home ranges and core activity areas and we investigated the daily, seasonal and altitudinal movements of brown bears in the Eastern Romanian Carpathians and surrounding high hills. The median MCP95% home ranges of brown bears was 629.92 km 2 and the median size of core activity areas (estimated as 50% kernel density) was 36.37 km 2 , with no significant differences between males and females. The mean daily distance travelled, measured as daily displacement length, was 1818 m and an analysis of seasonal movements indicated significant differences between seasons (greatest movements during the Hyperphagia season). The GPS-collared brown bears travelled between a minimum altitude measured at ~234 m and a maximum at ~1634 m. Analysing the spatial overlap between the estimated home range and the game management units (GMU) limits, we obtained a median number of 8 GMUs overlapping totally or partially with estimated home range polygons. Our study, using GPS telemetry, highlights the complex spatial ecology of the brown bear in the Romanian Carpathians, with larger home range size than those estimated in other European brown bear populations and with daily movements that vary by season and within a large altitude range. Our study supports the implementation of brown bear monitoring at a regional scale, rather than focusing on county level GMUs as the monitoring unit.
... This mountain range, despite the natural fragility of its ecosystems, is the first destination for outdoor winter sports in the world, which is emblematic of the anthropogenic pressure (Elsasser and Messerli, 2001). The study area is partially inside a protected mountain area (Adamello Brenta Natural Park, PNAB) of particular faunal importance for the historical presence of the last alpine population of brown bear (Ursus arctos) that was recently reintroduced (Preatoni et al., 2005), as well as for the current recolonization of the wolf (Canis lupus; Ražen et al., 2015). ...
... Relative to TEAM's, our protocol differed because we set one camera trap site every 4 km 2 instead of 2 km 2 . This compromised between maximizing the overall area monitored, especially given the large home range of brown bears (Preatoni et al., 2005;Groff et al., 2015), and avoiding too large gaps between camera trap sites ( Fig. 1). In addition, being the area diffusely covered by forestry roads and trails, which we considered suitable sites for detecting passing wildlife, sampling sites were chosen to fall equally on these categories. ...
As human activities increase in natural areas, so do threats to wildlife, potentially leading to immediate and long-term impacts on species’ distribution, activity, reproduction and survival. This is particularly relevant for large-bodied vertebrates that are especially sensitive to human presence and human-driven habitat changes. Assessing the impact of anthropogenic disturbance requires data on species distribution and activity patterns of target species in relation to human presence and infrastructures. Here, we used camera trap data to study the influence of anthropogenic disturbance on the community of medium-to-large mammals in a mountainous area in the eastern Italian Alps, with emphasis on the local population of brown bear (Ursus arctos). In 2015, we sampled a study area of 220 km² with 60 camera trap locations adopting a systematic grid. Such design was inspired by the terrestrial vertebrate monitoring protocol developed by the TEAM Network, a pan-tropical biodiversity programme. Camera traps run for 30 days in each site and cumulated 1,978 camera trapping days, yielding 1,514 detection events of 12 species of mammals. For the 8 most recorded species, we used detection/non-detection data to model estimated occupancy and detection probability in relation to a suite of environmental and disturbance covariates. Our analysis revealed that human disturbance plays a significant role in influencing species-specific detection probability, while we found little evidence of significant relationship between occupancy and anthropogenic disturbance. For example, we found that brown bear’s detectability was negatively correlated with capture rate of humans at sampling sites, and positively correlated with distance from settlements. We also assessed species-specific daily activity patterns and found that, for all species, the overlap with human diel pattern decreases significantly at sites with higher human presence. We also discuss the potential of our approach for building cost-efficient and long-term monitoring of mammals.
... The changes in the rates of home range expansions implies a change in movement behavior from large scale exploration during early stages of release to smaller scale exploration after initial home ranges were established and the animals became more familiar with the environment. Similar behavior was found in previous studies of reintroduced carnivores that had the highest rates of movement in the first few months after release (Hunter 1998, Preatoni et al. 2005. The cumulative home ranges of two of the lion groups (F-release 1 and M-release 2) reached a long-term stabilization while M-release 1 continued to expand its home range over the entire study period. ...
... The importance of release sites in affecting movements was also revealed by the behavior of lions returning to the area of their release after initial dispersal during their early post-release movement (Yiu et al. 2015). Although studies of various reintroduced mammal species had shown successful home range establishments (Preatoni et al. 2005, Wauters et al. 2015, the location of home ranges in relation to the sites of release over time have rarely been addressed. Our study suggests a considerable influence of the location of the release site on subsequent home range establishment and utilization. ...
Understanding of animal spatial behavior is essential for informed management decisions. In southern Africa, reintroduction of lions (Panthera leo) to small reserves (<1000 km2) has increased in recent years but studies on their ranging behavior in these enclosed systems remain lacking. We applied Time Local Convex Hull (T-LoCoH) methods to study the home range establishment and utilization of 11 lions reintroduced to Dinokeng Game Reserve, South Africa, during 2011 through 2014. Lions established home ranges close to their release sites and during the following three years their home range sizes continued to increase, but in each individual case it remained smaller than half of the reserve area (< 70 km2). Space use strategies differed between core and entire home range, with higher frequency of visits found in core areas. Exceptionally high rates (> 60 separate visits) around the largest dam and along rivers suggest the importance of water and its surrounding vegetation in the lions' space utilization pattern. The home range size did not differ with season or sex of the individuals, whereas shifts in locations of home ranges revealed differences in the response of the two sexes to territorial conflicts and management interventions. Our study shows a dynamic home range utilization pattern and highlights the importance of both fine-scale space use patterns (frequency and duration of visits) and broad-scale home range changes in understanding the ranging behavior of reintroduced animals. This article is protected by copyright. All rights reserved
... Our study confirmed the results of previous studies that habitats with great importance for the bears, which they actively select, were mainly forests and transitional woodland/shrub (preatoni et al. 2005, MertZaniS et al. 2005, Moe et al. 2007, pop et al. 2012. For all tracked bears forests represented the largest part of the territory used by the bears and at the same time were greatly preferred. ...
... The preferred forest type depended on its availability in the natural vegetation cover in the study area, which was demonstrated also in other studies (preatoni et al. 2005, MertZaniS et al. 2005, Moe et al. 2007, pop et al. 2012. ...
This is the first GPS-telemetry study based on four brown bears in Bulgaria revealing data about their home range and habitat use. The brown bear is frequently the cause of conflicts with humans. For better understanding of the species needs, investigations on the size of the home range and the habitat use are crucial. Our results showed that the home range of the Bulgarian brown bear was similar to those of bears on the Balkan Peninsula (65 km2 for adult female and 212 km2 for young male in dispersal). Brown bears preferred forest areas and shrubs. They avoided actively open terrains and human-influenced habitats. Size of the core area of bears is around 16% of the home-range size (based on kernel 50% contour).
... The elevation range known to be preferred by bears in southern Europe (i.e. 500-2000 m a.s.l.) is well represented in the study area (Clevenger et al., 1992;Dupré et al., 1998;Preatoni et al., 2005). The average human population density is 86/km 2 with local and seasonal variation due to high winter and summer tourism. ...
... The Eurasian brown bear (U. a. arctos) was historically widespread in the area, but in the 1990 the species was on the brink of extinction with only three males left. The present population is the result of the releases of 10 animals translocated from Slovenia from 1999 to 2002 (Mustoni et al., 2003;Preatoni et al., 2005). The area supports a stable presence for the species (Figure 1) (Tosi et al., 2015) and it is potentially connected with the eastern Dinaric-Pindos populations by two corridors (Preatoni and Tattoni, 2006;Peters et al., 2015) occasionally used by dispersing individuals. ...
The behaviour of marking trees by the brown bear occurs throughout the range of presence of the species. It has recently been recognised as a mean of intra-specific chemical communication, besides the likely function of ecto-parasite removal, and evidence from grizzlies showed that scent marking of trees is mainly performed by adult males during the breeding season. However, detailed studies on this behaviour in the Euroasian brown bear are lacking. We conducted a three year study on a wild bear population of 50 individuals in the Eastern Italian Alps, using camera traps. We aimed to assess the use of trees by bears’ age and sex classes, its temporal variation, and to determine key habitat and human disturbance drivers of the intensity of use of rub trees. Camera trapping yielded more than 500 videos of bears from more than 9000 camera trapping days, age and sex classes were identified in 59% of the videos. Results showed that rubbing was mainly performed by adult males, with females and sub-adults that only occasionally rubbed. Rubbing was performed more during the breeding season, confirming that the main function of this behaviour is associated to males' breeding strategy. Olfactory investigation was performed by bears of all ages and sexes, indicating the importance of scent marking at rub trees for intra-specific communication. We used the camera trapping event rate as a raw index of intensity of usage of rub trees and found it to be affected by aspect, type of roads and passage of motor vehicles at the sites, while the passage of people did not affect it. We also estimated bear occupancy and detectability and found that the latter was influenced by trail type and distance from roads and buildings. Our study provides a first contribution to the use of rub trees by brown bears in the Alps.
... Such behaviour has been interpreted as a rejection to the forced dispersal and typically results in lowsite fidelity, i.e. animals are unwilling to settle in the new area (Miller et al. 1999). Understanding movement patterns in the early post-release period is thus critical for the survival and reestablishment of reintroduced animals (Preatoni et al. 2005;Berger-Tal and Saltz 2014). ...
... Dispersal from the release sites varied between lion groups and did not coincide with changes in movement rates. This differs from the increase in distance of released lions from boma reported by Hunter (1998) and Kilian (2003) but is similar to the diverse dispersal patterns found in other translocated or reintroduced carnivores (Linnell et al. 1997;Preatoni et al. 2005). Various factors including intra-specific interactions, internal states of individuals, habitat quality and experiences in natal habitats are suggested to influence dispersal and settlement decisions of animals (Benard and McCauley 2008;Stamps et al. 2009;Santini et al. 2013). ...
Reintroductions have been increasingly used in carnivore conservation. Animal movement influences fitness and survival and is the first behavioural response of reintroduced animals to ‘forced dispersal’ in a new habitat. However, information available on early post-release movement of reintroduced carnivores remains limited. We studied movements of 11 reintroduced lions (Panthera leo) in Dinokeng Game Reserve, South Africa, in their first season of release and investigated changes in movements over time. Movement patterns of lions were more diverse than expected and varied between sexes and individual groups. Some lion groups returned to the area surrounding the release site after initial exploration and avoided human settlements, suggesting that vegetation and human disturbances influenced dispersal upon release. Cumulative home range size continued to increase for all lions despite individual differences in movement patterns. We highlight the importance of considering the variation in individual-specific behaviour and movement patterns to assess early establishment and reintroduction success.
... The project aimed at restoring a minimum vital population (40–60 individuals) in the Southern Alps in the mid-long term. To the purpose, 10 bears (7 females and 3 males) were translocated from Slovenia, where the population is genetically similar to that of Trentino (Randi et al. 1994; see also Mustoni et al. 2003; Preatoni et al. 2005), into the area where bear presence was still documented. In order to envisage future scenarios for the Italian Alpine bear population and to gain new insights in preparation for further reintroduction efforts, we analysed the outcomes of the reintroduction project in Trentino, focusing on (i) the study area/used space in relation to the population growth and structure, and (ii) the human–bear conflict, i.e., economic damages and social acceptance. ...
... In the case of Slovenia, due to its natural process of forestation , the area which represents a favourable habitat for bears is increasing rapidly (Jerina et al. 2003). In accordance with these findings, this reintroduced population appears to select deciduous forests and avoid areas with anthropogenic disturbance (Preatoni et al. 2005). Moreover, on a broad scale, Güthlin et al. (2011) showed that successful bear recovery in the Eastern Alps is unlikely to be inhibited by a lack of biophysical habitat. ...
... The ten models were largely consistent in terms of which variables were significantly related to the response Landscape Ecol the presumed source population of bears in the Carpathian Mountains; (ii) the use of traditional livestock husbandry techniques to minimize damage from bears; and (iii) some tolerance among shepherds to occasional conflict with bears. Unlike elsewhere, avoidance of human settlements by bears (Posillico et al. 2004;Preatoni et al. 2005;Nellemann et al. 2007) and financial incentives (Maclennan et al. 2009;Banerjee et al. 2013) appeared to play negligible roles in facilitating human-bear coexistence. ...
... Alternatively, local connectivity may be related to shrub cover which was not accounted for in our analyses, and this may partly explain the lack of statistical significance of local connectivity. In contrast to other studies (Posillico et al. 2004;Preatoni et al. 2005;Nellemann et al. 2007), bears were not affected by distance to human settlements. This may be because, at present, vehicle traffic does not increase strongly near settlements, and major agricultural machinery is also relatively uncommon, although agricultural intensification is likely in the future (Mikulcak et al. 2013). ...
Facilitating human-carnivore coexistence is a major conservation concern in human-dominated landscapes worldwide. Useful insights could be gained by studying and understanding the dynamics of human-carnivore coexistence in landscapes in which carnivores and humans have coexisted for a long time. We used a two-pronged approach combining ecological and social data to study coexistence of the brown bear (Ursus arctos) and humans in Transylvania, Romania. First, we surveyed 554 km of walking transects to estimate activity via a bear sign index, namely the proportion of anthills disturbed by bears, and used spatially explicit predictive models to test which biophysical and anthropogenic variables influenced bear activity. Second, we interviewed 86 shepherds and 359 villagers and community representatives to assess conflicts with bears and attitudes of shepherds towards bears. Our interdisciplinary study showed that bears and humans coexisted relatively peacefully despite occasional conflicts. Coexistence appeared to be facilitated by: (1) the availability of large forest blocks that are connected to the source population of bears in the Carpathian Mountains; (2) the use of traditional livestock management to minimize damage from bears; and (3) some tolerance among shepherds to occasional conflict with bears. In contrast, bear activity was unrelated to human settlements, and compensation for livestock losses did not influence people's attitudes toward bears. Our study shows that coexistence of humans and carnivores is possible, even without direct economic incentives. A key challenge for settings with a discontinuous history of human-carnivore coexistence is to reinstate both practices and attitudes that facilitate coexistence.
... If animals are released in a new territory, they lack knowledge of the spatial distribution of resources and thus typically perform long exploratory movements that enable them to become familiar with their surroundings (Preatoni et al. 2005, Letty et al. 2007). Such displacements have been described in the Alpine ibex (Tron et al. 1994, Pedrotti 1995, as in other large herbivore species (Jones andWitham 1990, Michallet andToïgo 2000). ...
... If animals are released in a new territory, they lack knowledge of the spatial distribution of resources and thus typically perform long exploratory movements that enable them to become familiar with their surroundings (Preatoni et al. 2005, Letty et al. 2007). Such displacements have been described in the Alpine ibex (Tron et al. 1994, Pedrotti 1995, as in other large herbivore species (Jones andWitham 1990, Michallet andToïgo 2000). Besides implying an increased energy expenditure for translocated animals, these movements may end in dispersing from the target release site (Moorhouse et al. 2009) and eventually in mortality (Letty et al. 2003). ...
The adaptation of translocated organisms to a new environment in the first years after their release is crucial in translocation programs because it may affect survival and reproductive success. Therefore, identifying the factors determining resource selection by the relocated animals is essential to improve the planning and the outcome of such programs. Using data collected in 20062009 in the framework of a restocking program, we studied the temporal variation of habitat selection in 14 translocated Alpine ibex (Capra ibex) during the year of their release and the following 3 years. We hypothesized a progressive adaptation of the translocated individuals, highlighted by a gradual decrease in the dissimilarities between translocated and resident individuals in ecological characteristics and social behavior. We tested the differences in habitat selection and home range size between the translocated and resident individuals and compared the spatial overlap between the groups. As expected, the dissimilarities decreased annually. The translocated and resident ibex almost immediately selected the same habitat resources, but the translocated individuals required 3 years to become fully socially assimilated. Our results indicated that habitat selection by gregarious species in a new environment is primarily driven by specific ecological requirements and that sociality plays a significant role. The translocated individuals tended to colonize areas already occupied by residents, either to fulfill social requirements and/or because the location of resident individuals may indicate high-quality habitat. This pattern of behavior must be considered in the planning of translocation programs because habitat selection can affect the outcomes of the programs.
... Dispersing individuals leave their natal sites in the breeding range, which is at the core of the presence range, colonizing first the closest available areas (Støen et al., 2006;Zedrosser et al., 2007). In addition, as has been seen in this and other populations, bears tend to colonize areas with low human impact that serve as a refuge from human-induced mortality (Martin et al., 2012;Fern andez et al., 2012;Preatoni et al., 2005;Naves et al., 2003). Direct persecution and disturbance of large carnivores, often in association with conflicts with humans, are behind this general pattern (Cardillo et al., 2004;Wolf & Ripple, 2017;Woodroffe, 1998). ...
Abstract Monitoring changes in the status of threatened and endangered species is critical for conservation, especially when these changes can be more dynamic than management actions. We studied how the range of the endangered Cantabrian brown bear (Ursus arctos) population has recovered after a long period of decrease. We estimated the presence range (using all available data on bear presence) and the breeding range (using data on females with cubs presence) in: 1982–1992, 1993–2002, and 2003–2012; to analyze temporal dynamics in the spatial extension of these ranges between periods. For the presence range, we observed an initial reduction of 25% between the first two periods maintaining two isolated subpopulations, followed by an increase of 70% in the third period that merged the subpopulations into a single population. The breeding range represented about 50% of the presence range and was stable between the two first periods and increased by 30% in the last period. Despite that increase two spatial breeding cores remained separated across all periods. Generalized linear models analyzing the factors affecting extinction and colonization between periods showed that bears expanded to areas closer to the center of the population and with low human disturbance. Our model projection predicted correctly a 77% of the areas newly colonized for the period 2013–2022 (112% increases in relation to 2003–2012). Finally, we identified that the recovery plans defining the guidelines for the management of this population are outdated and its application only covers around 50% of the current presence range and 40% of the predicted range. More dynamic legal and management approaches are needed to avoid conservation success turning into failure, especially for charismatic species whose management is often subject to social conflicts.
... Also, the consideration of landscape characteristics explaining variation in the size and the shape of home ranges provided us with a more realistic measure of space use. (Dahle and Swenson, 2003) or in Trento province in Italia [34,1813] km 2 (Preatoni et al., 2005)). However, we supposed that all males and all females had a similar home range size, which can be a source of bias if some individuals display higher movement abilities. ...
Connectivity, in the sense of the persistence of movements between habitat patches, is key to maintain endangered populations and has to be evaluated in management plans. In practice, connectivity is difficult to quantify especially for rare and elusive species. Here, we use spatial capture-recapture (SCR) models with an ecological detection distance to identify barriers to movement. We focused on the transnational critically endangered Pyrenean brown bear (Ursus arctos) population, which is distributed over Spain, France and Andorra and is divided into two main cores areas following translocations. We integrate structured monitoring from camera traps and hair snags with opportunistic data gathered after depredation events. While structured monitoring focuses on areas of regular bear presence, the integration of opportunistic data allows us to obtain information in a wider range of habitat, which is especially important for ecological inference. By estimating a resistance parameter from encounter data, we show that the road network impedes movements, leading to smaller home ranges with increasing road density. Although the quantitative effect of roads is context-dependent (i.e. varying according to landscape configuration), our model predicts that a brown bear with a home range located in an area with relatively high road density (8.29 km/km²) has a home range size reduced by 1.4-fold for males and 1.6-fold for females compared to a brown bear with a home range located in an area with low road density (1.38 km/km²). When assessing connectivity, spatial capture-recapture modeling offers an alternative to the use of experts' opinion when telemetry data are not available.
... Also, the consideration of landscape characteristics explaining variation in the size and the shape of home ranges provided us with a more realistic measure of space use. (Dahle and Swenson, 2003) or in Trento province in Italia [34,1813] km 2 (Preatoni et al., 2005)). However, we supposed that all males and all females had a similar home range size, which can be a source of bias if some individuals display higher movement abilities. ...
Connectivity, in the sense of the persistence of movements between habitat patches, is key to maintain endangered populations and has to be evaluated in management plans. In practice, connectivity is difficult to quantify especially for rare and elusive species. Here, we use spatial capture-recapture (SCR) models with an ecological detection distance to identify barriers to movement. We focused on the transnational critically endangered Pyrenean brown bear (Ursus arctos) population, which is distributed over Spain, France and Andorra and is divided into two main cores areas following translocations. We integrate structured monitoring from camera traps and hair snags with opportunistic data gathered after depredation events. While structured monitoring focuses on areas of regular bear presence, the integration of opportunistic data allows us to obtain information in a wider range of habitat, which is especially important for ecological inference. By estimating a resistance parameter from encounter data, we show that the road network impedes movements, leading to smaller home ranges with increasing road density. Although the quantitative effect of roads is context-dependent (i.e. varying according to landscape configuration), our model predicts that a brown bear with a home range located in an area with relatively high road density (8.29km/km2) has a home range size reduced by 1.4-fold for males and 1.6-fold for females compared to a brown bear with a home range located in an area with low road density (1.38km/km2). When assessing connectivity, spatial capture-recapture modeling offers an alternative to the use of experts’ opinion when telemetry data are not available.
... Movement is the first behavioural response of translocated animals to "forced dispersal" in a new habitat (Stamps & Swaisgood 2007). Thus, movement patterns in the early post-release period are critical for the survival and establishment of reintroduced animals (Preatoni et al. 2005, Berger-Tal & Saltz 2014. However, information available on the early postrelease movement of translocated carnivores remains limited for most species primarily due to the lack of published data on telemetry monitoring early after the translocations (Vandel et al. 2006, Yiu et al. 2015 The Eurasian lynx (Lynx lynx) is a solitary predator with a social organisation based on territoriality. ...
Translocations of individuals for reintroductions and population reinforcements have been increasingly used in carnivore conservation. Movement is the first behavioural response of reintroduced animals to ‘forced dispersal’ in a new habitat and our study investigated space use and movement patterns of six male Eurasian lynx (Lynx lynx) translocated from Carpathian to Dinaric Mountains and released at four different sites in Croatia and Slovenia. Data was collected during their early post-release period (i.e. 3 months after the release) to investigate first behavioural response following the translocation. Released lynx were monitored with GPS-GSM-VHF telemetry collars set to collect GPS locations in intervals between 4h and 24h. All animals settled during the study period, on average 23 days (SD=16.5) after the release. Although it is outside of the monitoring period that was the focus of this study, two lynx left their first territory 102 and 92 days after their release and went in second exploratory movement. The main movement direction of the released animals was to the NW-SE, corresponding to the orientation of the predominant ridgelines of the Dinaric mountain range. Furthermore, by comparing the use and availability of the terrain aspect, we concluded that the lynx chose to move along the mountain range and not perpendicular to the mountain, i.e. they avoided moving uphill and downhill. First kill sites of all animals were detected on average 3.4 days (SD=1.7) after the release. This study brought valuable theoretical and practical knowledge on the early movement behaviour of translocated lynx that should be taken into consideration when planning translocations.
... We consider this process to have two distinct phases: the search phase where an animal explores the landscape and selects a general area to settle in, followed by an establishment phase in which the newly formed home range is "fine-tuned" to best fit the animal's needs (McNicol et al., 2020). Both phases are heuristic and may take an extended amount of time (Dolev et al., 2002;Preatoni et al., 2005;Sarkar et al., 2016). In this paper we focus on the dynamics of the establishment phase. ...
Translocated animals typically find themselves in a novel environment in which they must establish a home range in a manner that will maximize their fitness. We hypothesized that the initial establishment of a home range is followed by adjustments expressed as home range shifting, and occurs as familiarity with the landscape increases, until the home range is stabilized. We studied the process of home range shifting in 42 female Persian fallow deer (Dama mesopotamica) reintroduced into the Galilee, Israel over a period of 2–5 years. We used changes in the degree of home range overlap between consecutive years as an indicator of stabilization. We then compared how the mean percent cover of the key vegetation types (woodland, scrubland and open pastures) differed between the areas abandoned in the first year's home range and the areas added to the last year's home range relative to the first (using a weighted paired t-test). We also compared the distribution (using χ2 test of independence and Levene's test for homogeneity of variance) of %cover of the 3 vegetation types between the first and last year's home range. The average home range overlap increased over the 5 years following the first release. During the first-year post release, deer avoided open pastures and preferred woodland. In later years deer increase in the % open pastures (weighted t-test: p < 0.001) and decreased the % woodland cover (weighted t-test: p = 0.07) by abandoning areas with little open pasture and steeper terrain and moving into areas with more open pasture and moderate terrain. Variance of the cover types across individuals increased with time. We conclude that the home ranges of the reintroduced deer stabilized with time. The changes in vegetation and slope are driven by time-dependent changing needs reflecting a tradeoff between safety (refuge) and foraging. Our findings suggest that using the initially established home range to determine species preferences can create a misleading picture of what the optimal home range of the species really is. Individual variation in term of preferences can take a few years to be expressed due to the initial high-risk perceived by individuals in a novel environment.
... Conservation translocations of North American and European bear species have been extensively reported, with reintroductions in Europe occurring as early as the 1930s (Ursus americanus: Alt & Beecham, 1984;Stiver et al., 1997;Eastridge & Clark, 2001;Clark, 2009;U. arctos: Buchalczyk, 1977;Jonkel et al., 1980;Clark et al., 2002;Preatoni et al., 2005;Huber, 2010). Thus far however, reports on the outcomes of Malayan sun bear Helarctos malayanus releases have been limited (Fredriksson, 2005;Abidin et al., 2018). ...
Well-conceived programmes for releasing wildlife are essential due to the growing numbers of animals confiscated from the illegal wildlife and pet trade. To support the development of such programmes, we describe experiences gained from the release of Malayan sun bears Helarctos malayanus in the Southern Cardamom Mountains of southwest Cambodia. Following rehabilitation and acclimatisation, three sun bears were released on two diff erent occasions. Prior to their release, the bears had been in captivity since infancy. Post-release monitoring with GPS collars showed that all three bears were capable of sustaining themselves unassisted and avoided human interactions after their release. However, all three encountered problems which later resulted in their recapture or death: two were caught in snares and one was killed by a wild resident. Our results demonstrate that sun bears can acquire the skills necessary for survival and that captivity need not be a barrier to successful release if the animals are provided with large forested enclosures that encourage 'natural' behaviours and human contact is minimised prior to release. Our experiences also emphasize the importance of considering hunting pressure and presence of conspecifics at release sites when developing release programmes.
... Winter habitat use by bears [34] and other species, such as mountain goats (Oreamnos americanus) [35] and wolverines (Gulo gulo) [36], has been negatively associated with heli-skiing areas. In addition to wildlife disturbance and habitat avoidance, heli-skiing and snowmobile use, can trigger avalanches on steep slopes (>25˚) [37], which increases the risk of fatality for both people [38,39] and bears [40,41]. Whether the consequences of these risks are acceptable is a management decision reliant upon empirical data concerning wildlife habitat requirements necessary to inform public opinion. ...
Winter recreation and tourism continue to expand worldwide, and where these activities overlap with valuable wildlife habitat, there is greater potential for conservation concerns. Wildlife populations can be particularly vulnerable to disturbance in alpine habitats as helicopters and snowmachines are increasingly used to access remote backcountry terrain. Brown bears (Ursus arctos) have adapted hibernation strategies to survive this period when resources and energy reserves are limited, and disturbance could negatively impact fitness and survival. To help identify areas of potential conflict between helicopter skiing and den-ning brown bears in Alaska, we developed a model to predict alpine denning habitat and an associated data-based framework for mitigating disturbance activities. Following den emergence in spring, we conducted three annual aerial surveys (2015-2017) and used locations from three GPS-collared bears (2008-2014) to identify 89 brown bear dens above the forest line. We evaluated brown bear den site selection of land cover, terrain, and climate factors using resource selection function (RSF) models. Our top model supported the hypothesis that bears selected dens based on terrain and climate factors that maximized thermal efficiency. Brown bears selected den sites characterized by steep slopes at moderate elevations in smooth, well-drained topographies that promoted vegetation and deep snow. We used the RSF model to map relative probability of den selection and found 85% of dens occurred within terrain predicted as prime denning habitat. Brown bear exposure to helicopter disturbance was evident as moderate to high intensities of helicopter flight tracking data overlapped prime denning habitat, and we quantified where the risk of these impact was greatest. We also documented evidence of late season den abandonment due to disturbance from helicopter skiing. The results from this study provide valuable insights into bear denning habitat requirements in subalpine and alpine landscapes. Our quantitative framework can be used to support conservation planning for winter recreation industries operating in habitats occupied by denning brown bears.
... Mid altitude areas (500-1000 m) are characterized by diffuse farming and livestock grazing as well as fruit production, covering 25% of the provincial territory. It is the only Alpine area in which brown bears have never disappeared and in the late 1990s the provincial administration supported a restocking project that brought nine individual bears from Slovenia (Preatoni et al., 2005). Since then, the bear population has increased and in 2018, a minimum number of 39 individuals was recorded (Groff et al., 2019). ...
Social conflicts over large carnivores are becoming more frequent following the general recovery of large carnivores in human shaped landscapes in Europe. To manage conflicts over large carnivores a detailed knowledge is necessary on the social, economic, cultural but also interpersonal dimensions of the conflicts. This can be achieved through a participatory engagement of all stakeholders within a procedure tailored to local contexts. We looked at conditions necessary for implementing the above approach in areas of intense large carnivores-human conflict across Europe (bear and wolves), and where traditional management conflict policies do not appear to be successful, as often based on urgent responses to emergency situations. We focussed on four areas in Europe where we interviewed stakeholders to characterize the conflicts and assess the potential for mitigation interventions through participatory processes. We focused on four key aspects related to social conflicts: (a) perception of the current situation and relationship with other stakeholders; (b) availability and accessibility of information and communication; (c) economic, ecological and social impacts; and (d) promotion of coexistence and participatory processes. We show that (lack of) trust between stakeholders and the relevant authorities as well as the lack of genuine communication among stakeholders were the key features that characterized social conflicts related to large carnivores. With specific reference to large carnivores, the lack or inaccessibility of reliable information was reported in all cases by all stakeholders, as well as the need for proactive and inclusive policies developed and implemented by the relevant authorities. A consistent message was that support and engagement from relevant management institutions was pivotal for effective management of conflicts over large carnivores. Our findings highlight the importance for conflict mitigation of a deeper and mutual understanding of issues prior to the implementation of participatory processes.
... Interestingly, salamanders had a high sedentariness in their first summer in the wild, as high as that in winter, which was much higher than in the second summer. Reintroduced/translocated animals may exhibit exploratory movement after release, and would move more frequently with longer distances to search for suitable habitat (e.g., [39][40][41]). Our observed movement patterns were contrary to these findings. ...
Background: Very little is known about the temporal or spatial movement patterns of Chinese giant salamanders (Andrias davidianus) due to their rarity, remote habitat and secretive nature. Commercial breeding farms provide a unique opportunity as a source of animals for reintroduction and spatial ecology studies, which will help inform conservation management efforts for this threatened species. We surgically implanted radio transmitters into the body cavity of 31 juvenile giant salamanders, and these salamanders were subsequently released into two small river systems (Donghe and Heihe Rivers) located in the Qinling Mountains of central China and were monitored daily from May 2013 to August 2014.
Results: Only two salamanders survived through the end of the project at the Heihe River compared with 12 at the Donghe River, thus movement data for salamanders released at the Heihe river are described individually. The overall sedentariness (ratio of no movement to all observations) for the two salamanders at the Heihe River was 0.29 and 0.28 compared to the average sedentariness of 0.26 ± 0.01 for the 12 salamanders at the Donghe River. Mean daily movement was 15.4m± 0.7 at the Heihe River compared to 9.3m± 0.3 at the Donghe River. Overall linear home range (LHR) was 246m and 392m for the two salamanders at the Heihe River, compared with a mean LHR of 227.2m± 70.5 at the Donghe River. The Donghe salamanders exhibited different movement patterns across
seasons, having higher sedentariness, shorter daily movement, and smaller LHR in winter than in summer. Upstream dispersal and fidelity to release site were recorded at both rivers. The mean dispersal distance for the Donghe River salamanders was 145.3m± 61.9, while the two surviving salamanders at the Heihe River had a dispersal distance of 211m and 205 m.
Conclusions: This project provides important insights on the movement ecology of a large aquatic salamander species, and in particular, our results may assist with reintroduction efforts by developing best management practices on when and where to release animals as a conservation strategy.
... For example, European brown bears (Ursus arctos) released in Austria and the Pyrenees moved larger distances than did wild bears in southern and northern European populations (Ordiz et al. 2007). Brown bears released in the Italian Alps revealed strong sex-based differences in postrelease movement (Preatoni et al. 2005). In that study males showed restricted movements in the months after release, whereas females were more variable, in some cases moving dozens of kilometers away. ...
... The project aimed at restoring a minimum vital population (40-60 individuals, Dupré et al. 2000) in the Southern Alps in the mid-long term. To that purpose, 10 bears (7 females and 3 males) were translocated during 1999-2002 from a genetically similar population in Slovenia into the areas where the presence of non-reproducing individuals was still documented (Mustoni et al. 2003;Preatoni et al. 2005;Tosi et al. 2015). At the end of 2017, the reintroduced population counted 52-63 individuals (Groff et al. 2018). ...
The management and conservation of large carnivores is a challenging task because of their great spatial requirements and the hostility encountered in certain socio-political contexts. Particular fundamental requirements concern those species, such as brown bears (Ursus arctos), that need to hibernate in order to optimise the balance between energy acquisition and energy expenditure during winter. Thus, a thorough knowledge of bears’ winter behaviour is critical to ensure a proper management and protection of this species. The aim of the present study was to assess the location and features of the hibernation sites of a bear population reintroduced in the Central-Eastern Alps (Italy). Sixty-five bear dens and 85 unused caves were located and described. Bears were found to select natural rock caves (N = 64) located in medium-high slope at an altitude between 520 and 1950 m a.s.l.. Caves usually were in poorly accessible areas with low human disturbance. In particular, the comparison between used and unused caves showed that three main factors drove the selection of hibernation sites by brown bear: (i) small entrance and suitable length of the cave, (ii) their location in wooded areas and (iii) high level of solar radiation and favourable internal micro-climatic conditions. Caves selected by bears showed significantly higher monthly temperatures from October to March (especially in October and November, when bears typically search for a suitable hibernation site) than caves that were not used despite their similar structural characteristics. No differences in cave selection were found between native and reintroduced bears, suggesting that cave selection was driven by objective cave characteristics, rather than by population-specific traditions. Lastly, among different age and sex classes, pregnant females were found to select caves with a greater total length, located in more hidden areas and with more solar radiation around the entrance. Brown bear cave selection seems therefore to be driven mainly by measures, exterior habitat features and inner temperature.
... We performed whole-genome sequencing of six Apennine bears and six additional European brown bears from Greece (two individuals), Slovakia (two individuals), the Alps (one individual), and western Spain (one individual) ( Fig. 1A and SI Appendix, Table S1). The Alpine individual was born in south Slovenia but sampled about 400 km west in the Adamello National Park in Italy, where it was released in the year 2000 during a reintroduction project (21). Paired end Illumina sequences were aligned A D B E C Fig. 1. ...
Significance
A small and relict population of brown bears lives in complete isolation in the Italian Apennine Mountains, providing a unique opportunity to study the impact of drift and selection on the genomes of a large endangered mammal and reconstruct the phenotypic consequences and the conservation implications of such evolutionary processes. The Apennine bear is highly inbred and harbors very low genomic variation. Several deleterious mutations have been accumulated by drift. We found evidence that this is a consequence of habitat fragmentation in the Neolithic, when human expansion and land clearance shrank its habitat, and that retention of variation at immune system and olfactory receptor genes as well as changes in diet and behavior prevented the extinction of the Apennine bear.
... Increased travelling speed through areas of high human disturbance and increased use of cover to reduce human encounters have also been found in other large carnivores (e.g. increased traveling speed in cougars and lions: Dickson et al. 2005, Valeix et al. 2012, Oriol-Cotteril et al. 2015; increased use of dense cover in spotted hyenas and brown bears: Boydston et al. 2003, Preatoni et al. 2005, suggesting that these behavioral ungulate in summer and the rest of the year, respectively) is much lower than what was expected from the abundance of the different ungulate species (0.8) thus indicating strong avoidance of domestic animals by lynx (p prop.test 0.0001) as anticipated by prediction 5. ...
Understanding animal space us is a fundamental concern in Ecology. Predator-prey interactions are a behavioral response game where predators try to find prey, and prey are trying to avoid the predators, thereby shaping animal space use and habitat selection. In the process both predator and prey tradeoff between risk avoidance and food acquisition in order to maximize their fitness. As such predator-prey dynamics have fascinated many generations of ecologists. At the same time the impact of human activities on ecosystem processes have become increasingly evident over the years and almost all habitats on earth today have been altered to some degree by humans. As a consequence humans can be considered as ecological players of ecosystem processes that shape the behavior and demography of their commensal species. In the presence of humans large top predators may be downgraded in the food chain or compete with humans for their prey. Furthermore prey species themselves have to tradeoff between risk avoidance towards humans or their natural predators. It was the goal of this thesis to look at various aspects involved in shaping the space use patterns of the Eurasian lynx (Lynx lynx) and its main prey, the European roe deer (Capreolus capreolus) and to characterize the spatiotemporal drivers of habitat selection and risk avoidance of both players in a human dominated environment. By focusing on both predators and prey I identify different key components of the behavioral response game between Eurasian lynx and European roe deer. In the first chapter I investigated how tradeoffs between risk avoidance and resource abundance in human-altered environments affect habitat selection of Eurasian lynx. In particular, I studied how spatial scale interacts with the intrinsic behavioral state of Eurasian lynx in shaping the response to temporal and spatial fluctuations in human activity and prey availability. I show that lynx tradeoff between anthropogenic risk and prey density by using areas of high prey density during times of low human disturbance. This tradeoff differs among behavioral states and is dependent on the spatial scale considered. In the second chapter I focused on the prey and tested how lynx and humans interact in shaping space use patterns of roe deer during the hunting season in fall. Multiple predators of a single prey may positively or negatively interact with each other via their prey. The same may be true for human hunters that compete with natural predators for the same prey. I explored how roe deer tradeoff between hunting and lynx predation risk and whether hunting increases the deer’s susceptibility to lynx predation. I found that roe deer avoid areas of high hunting risk during the hunting season at the expense of higher exposure to lynx predation risk. Furthermore there was strong evidence that lynx increased their hunting effort and hunting success during this time period. The results provided strong evidence that hunters facilitated lynx predation which resulted in superadditive mortality for deer during the hunting season. In environments with limited resources and time antipredator behavior may come at costs that ultimately affect prey demography. The strength of such non-consumptive effects (NCE) largely depends on the hunting mode of the predator. Ambush predators exert stronger NCE than active predators as they provide more persistent cues about predation risk than their widely roaming counterparts. While evidence comes from different taxonomic groups, evidence from large mammalian predator-prey systems is rare and equivocal. In the third chapter I looked at the occurrence and strength of NCE of the ambush predator, the Eurasian lynx on its main prey the European roe deer. According to ecological prediction I found that lynx evoked strong NCE that increased non-lynx-related mortality of roe deer in the study area. In summary, I focused in this thesis on identifying key drivers involved in shaping space use patterns of a large ambush predator and one of its main prey. Furthermore I characterized the spatiotemporal drivers of food acquisition and risk avoidance of both players in a human dominated environment. The presented results illustrate the tradeoffs between risk avoidance and food acquisition that affect decision making of all animals and show the potential costs of these tradeoffs in the form of reduced survival or reproduction. Finally the findings highlight the role of humans as ecological drivers of Ecosystem processes and may help developing efficient wildlife management plans that are needed for the conservation of large predators and their prey alike in human altered environements.
... Increased travelling speed through areas of high human disturbance and increased use of cover to reduce human encounters have also been found in other large carnivores (e.g. increased traveling speed in cougars and lions: Dickson et al. 2005, Valeix et al. 2012, Oriol-Cotteril et al. 2015; increased use of dense cover in spotted hyenas and brown bears: Boydston et al. 2003, Preatoni et al. 2005, suggesting that these behavioral ungulate in summer and the rest of the year, respectively) is much lower than what was expected from the abundance of the diff erent ungulate species (0.8) thus indicating strong avoidance of domestic animals by lynx (p prop.test Ͻ 0.0001) as anticipated by prediction 5. ...
Human related mortality is a major threat for large carnivores all over the world and there is increasing evidence that large predators respond to human related risks in a similar way as prey respond to predation risk. This insight recently led to the conceptual development of a landscape of coexistence that can be used to identify areas which can sustain large predator populations in human dominated landscapes. In this study we applied the landscape of coexistence concept to a large predator in Europe. We investigated to what extent Eurasian lynx Lynx lynx habitat selection is affected by human disturbance in a human dominated landscape. More specifically, we were interested in the existence of a tradeoff between the availability of roe deer, one of their main prey and avoidance of human disturbance and how this affects the spatio-temporal space use patterns of lynx. We found that lynx face a tradeoff between high prey availability and avoidance of human disturbance and that they respond to this by using areas of high prey availability (but also high human disturbance) during the night when human activity is low. Furthermore our analysis showed that lynx increase their travelling speed and remain more in cover when they are close to areas of high human disturbance. Despite clear behavioral adjustments in response to human presence, prey availability still proved to be the most important predictor of lynx occurrence at small spatial scale, whereas human disturbance was considerably less important. The results of our study demonstrate how spatio-temporal adaptations in habitat selection enable large carnivores to persist in human dominated landscapes and demonstrate the usefulness of the concept of a landscape of coexistence to develop adaptive management plans for endangered populations of large carnivores. This article is protected by copyright. All rights reserved.
... Milu dispersal from SMNNR was an exploratory process. Similar processes are found in rodents, herbivores and carnivores 6,7,[42][43][44] . The effectiveness of dispersal of Milu in the stable stage of dispersal was higher than that in the other two stages of dispersal. ...
The Milu (Père David’s deer, Elaphurus davidianus) became extinct in China in the early 20th century but was reintroduced to the country. The reintroduced Milu escaped from a nature reserve and dispersed to the south of the Yangtze River. We monitored these accidentally escaped Milu from 1995 to 2012. The escaped Milu searched for vacant habitat patches as “stepping stones” and established refuge populations. We recorded 122 dispersal events of the escaped Milu. Most dispersal events occurred in 1998, 2003, 2006 and 2010. Milu normally disperse in March, July and November. Average dispersal distance was 14.08 ± 9.03 km, with 91.41% shorter than 25 km. After 5 generations, by the end of 2012, 300 wild Milu were scattered in refuge populations in the eastern and southern edges of the Dongting Lake. We suggest that population density is the ultimate cause for Milu dispersal, whereas floods and human disturbance are proximate causes. The case of the Milu shows that accidentally escaped animals can establish viable populations; however, the dispersed animals were subject to chance in finding “stepping stones”. The re-wilded Milu persist as a meta-population with sub-populations linked by dispersals through marginal habitats in an anthropogenic landscape.
... Second, our models confirmed the importance of forested areas with low human disturbance to maintain habitat suitability and connectivity (Kobler and Adamic 2000;Preatoni et al. 2005;Martin et al. 2010;Fernández et al. 2012;Martin et al. 2012;Mateo Sánchez et al. 2013, 2014. We also found high importance of topographic complexity. ...
Context. Connectivity assessments typically rely on resistance surfaces derived from habitat models, assuming that higher-quality habitat facilitates movement. This assumption remains largely untested though, and it is unlikely that the same environmental factors determine both animal movements and habitat selection, potentially biasing connectivity assessments.
Objectives. We evaluated how much connectivity assessments differ when based on resistance surfaces from habitat versus movement models. In addition, we tested how sensitive connectivity assessments are with respect to the parameterization of the movement models.
Methods. We parameterized maximum entropy models to predict habitat suitability, and step selection functions to derive movement models for brown bear (Ursus arctos) in the northeastern Carpathians. We compared spatial patterns and distributions of resistance values derived from those models, and locations and characteristics of potential movement corridors.
Results. Brown bears preferred areas with high forest cover, close to forest edges, high topographic complexity, and with low human pressure in both habitat and movement models. However, resistance surfaces derived from the habitat models based on predictors measured at broad and medium scales tended to underestimate connectivity, as they predicted substantially higher resistance values for most of the study area, including corridors.
Conclusions. Our findings highlighted that connectivity assessments should be based on movement
information if available, rather than generic habitat models. However, the parameterization of movement models is important, because the type of movement events considered, and the sampling method of environmental covariates can greatly affect connectivity assessments, and hence the predicted corridors.
... In Southern Europe, brown bear (Ursus arctos arctos L. 1758) populations are scarce and isolated. Several countries are currently undertaking significant efforts to protect and reinforce local populations that have been on the verge of extinction (Taberlet et al. 1997, Wiegand et al. 1998, Mustoni et al. 2003, Preatoni et al. 2005, Mateo-Sanchez et al. 2014. To aid these population recovery efforts, a better understanding of the ecological role of the brown bear and its impact on local biodiversity is crucial. ...
Plant dispersal is crucial to maintaining plant community dynamics, especially in the current context of rapid environmental changes such as global warming and landscape fragmentation. We seized the opportunity to carry out a pilot study on endozoochorous dispersal by the endangered Pyrenean brown bear. We based our study on faeces collected by the Brown Bear Network and location data from three bears fitted with GPS collars and translocated from Slovenia to the Pyrenees in 2006. We studied 39 faecal samples, 25 of which contained seeds from two to three different taxa. We identified a total of 47 plant taxa, 30 to the genus level and 21 to the species level. The seeds from plants bearing fleshy fruits:
... They also search areas suitable for denning, which in the Bieszczady Mts are frequently located over 900 m (Gula & Frąckowiak 2000), resulting in bears recorded more often at higher altitudes. Low use of areas surrounding major roads and human settlements has been shown previously (Clevenger et al. 1992;Huygens et al. 2001;Wielgus et al. 2002;Kaczensky et al. 2003;Preatoni et al. 2005;Nellemann et al. 2007) and in the Bieszczady Mts this result is supported by the observation that people rarely see brown bears (Jakubiec 2001). Bears in the study area, however, frequently foraged on anthropogenic food: crops, fruits and meat deposed as bait by hunters (Frąckowiak 1997). ...
In Europe, brown bear Ursus arctos habitats frequently overlap with human settlements and infrastructure. We tested whether anthropogenic structures played an important role in habitat selection by brown bears in the Bieszczady Mountains, Poland. We analysed 668 signs of brown bear presence recorded during 6 counts along 246 km of transects (total 1,476 km) in spring, summer and autumn of 1993 and 1994. Habitat selection of bears was more related to habitat and altitude than to human factors. Avoidance of roads, settlements and forest clearings influenced habitat selection by brown bears in spring but less in summer and autumn.
... Range overlap seems to result from the relatively large home ranges of the adult males and appears to be a common feature in other bear populations in Europe and even in the cases of restocked populations like in Adamello-Brenta Alps Italy, suggesting that food abundance in the study area should not be a limiting factor (Preatoni et al., 2005) Habitat use of the studied brown bear sample was not proportional in all cases to the availability of the different habitat types in the study area, but appeared to be selective (Figs 3-8). Mixed agro-forestry habitats (MAG) were the habitat type mostly used by the sampled bears. ...
The brown bear (Ursus arctos L.) is a key species indicating the conservation status of natural
and seminatural mountainous ecosystems. Brown bear populations in Greece are confined to the
mountain ranges of Pindos and Rodopi. Systematic data on brown bear spatial behavior based
on telemetry data were lacking in Greece until 1997. This paper presents the results on brown
bear habitat use patterns monitored on an annual basis in the area of Grammos and NW Voio
mountains located in Northern Pindos range. A sample of six radiocollared brown bears (n = 6,
5 males - 1 female) was monitored from 1997 to 2002 using ground telemetry. Generated data
(n = 3,052 bearings and n = 739 radiolocations) were combined to an analysis of vegetation char-
acteristics identified through a classification of eight habitat types according to vegetation struc-
ture and dominant formations. Bear home range size varied individually from 102 sq. km to 507 sq. km. Seasonal variability of home range size was also evident with fall presenting the highest values ranging from 87sq. km to 314 sq. km. Bears showed clear preference for mixed agro-forestry
systems as well as for agricultural lands especially in the end of summer and beginning of fall. Forests with mixed broadleaved species including chestnuts (Castanea sativa) and hazelnuts (Corylus avellana) were also used more than expected. Brown bear habitat choice and preferences can be used as a decision making tool to delineate important areas and to take appropriate management and conservation measures for the targeted species and the related forest ecosystems.
... For example, an increase in forest coverage favors some species, such as tawny owls, brown bear, and red deer (Marchesi et al., 2006;Preatoni et al., 2005;Mattioli et al., 2001), and can have other positive effects on the environment, such as increases in soil stability and carbon storage (Veit et al., 2007). On the other hand, reductions of pastures, agricultural areas, and ecotones are linked to reductions in biodiversity Marriott et al., 2004;Sergio et al., 2005). ...
The abandonment of farming and agriculture is leading to an increase in forest coverage in most European mountain areas. Based on a long series of data (1859–2006), this study presents the development of a spatially explicit fine-scale Markov chain model to predict future changes in forests over a broad area and to assist the management of Paneveggio Nature Park, Italy. The results predict an increase in forest coverage and a reduction in the extent of open habitats, which are a priority for conservation. This protocol can be used for designing long-term management measures focusing on endangered habitats.
... The distributions of species can be calculated from various methods, including calculation of the area that lies within a minimum convex polygon, or convex hull, encompassing all the occurrences of a species (e.g. Preatoni et al. 2005; Miller et al. 2007; Sérgio et al. 2007; Sheth et al. 2008); or statistical modelling approaches that combines observations of species occurrences at sites with environmental and/or spatial characteristics of those sites (e.g. Papeş et al. 2007; Solano et al. 2007; Parolo et al. 2008; Thorn et al. 2009). ...
Rare species are growing as one of the main issues of concern in the effort to conserve biodiversity worldwide, since these species are assumed to undergo higher risk of extinction. Rare species are characterized by restricted geographic ranges, habitat specialization and/or small population sizes. Their distribution datasets usually have small numbers of observations, often gathered over long periods of time and of limited spatial accuracy, and lack valid absences. Veronica micrantha Hoffmanns. & Link is a rare plant species, endemic of the Iberian Peninsula and protected under the EU Habitats Directive. Under Article 17 of this Directive, EU Member States are obliged to undertake monitoring, assessment and reporting of conservation status for all habitats and species of Community interest found within their territory. In this study, we propose to evaluate the usefulness of predictive models as a promising alternative approach to conventional reporting and as tools to support cost-efficient monitoring programs. Reported occurrences of species distribution are used to estimate the potential distribution of Veronica micrantha based on two different approaches: minimum convex polygon (MCP) and species distribution modelling (SDM). The main difference between the two approaches is that the former overestimates the species distribution, whereas the latter gives a more conservative, and presumably more realistic, assessment of the distribution of the species while also allowing a better understanding of the relationship between species distribution and environmental conditions. At regional scale, corresponding to the Iberian Peninsula and including the whole range of the species, we modelled the distribution of the species using only climatic data. At sub-regional scale, in Northern Portugal, where the species is fairly distributed, we applied a combined predictive modelling approach, based on fitting SDMs using different sets of environmental predictors. Our results highlight the more informative character of this approach, providing a wider variety of potential species responses than traditional models. Therefore, the proposed approach constitutes a step forward in the study of the distribution patterns of rare species, as well as in the use of these more informative projections to improve the reporting and monitoring of the condition and trends of rare species.
... In Europe, for example, all Nordic brown bear populations are increasing, whereas local expansions have been recorded in a part of the Carpathian population in Slovakia, a part of the northwestern population in European Russia, and parts of the Alps-Dinaric-Pindos population in Croatia, Italy, and Slovenia (Zedrosser et al. 2001). Moreover, numerous reintroduction projects aimed at increasing the sizes of bear populations are under way in different parts of the world (Clark et al. 2002;Preatoni et al. 2005). Several studies indicate that the demography, dispersal, and other ecological parameters of expanding populations of large predators can be different from those of stable or declining populations (Bales et al. 2005;Pletscher et al. 1997;Swenson et al. 1998). ...
Although the brown bear (Ursus arctos) is generally classified as an endangered species, the size and range of several bear populations are increasing in different parts of the world. Understanding how this occurs is essential for the species' management. Using reliable signs of bear presence and models, we analyzed multiple aspects of the spatial expansion of the brown bear population in Slovenia from the Core Bear Protective Area (an area established in 1966 for the conservation of brown bears; hereafter, Core Area) toward the Alps and other parts of the country in 1945–1995. Bear population densities increased between 1945 and 1995, but densities decreased with distance from the Core Area. The observed proportion of females increased overall during the study period from 6% to 20%, but decreased with distance from the Core Area from 27% (0–10 km from the Core Area) to 5% (>70 km from the Core Area). This pattern likely is a consequence of male-biased dispersal, which can cause substantial changes in the sex structure of peripheral parts of populations in space and time. The population showed a net annual growth rate of 1.7%, and expanded spatially at an average rate of 1.6–1.9 km/year. Some females were recorded far from the Core Area (>80 km), suggesting that unlike in stable or declining populations, females in expanding populations can exhibit long-distance dispersal. However, the frequency of females that dispersed far was so small that it probably had little impact on the dynamics of the population expansion.
... In the Abruzzo Mountains of Central Italy, bears prefer deciduous forests and high altitude areas and avoid open scrub lands (Posillico et al., 2004). Re-introduced bears in Trentino, Italy select for deciduous forests and avoid areas with anthropogenic disturbance (Preatoni et al., 2005). In Spain, bears prefer beech and oak dominated forests and show an avoidance of roads and villages (Clevenger et al., 1992). ...
According to the Habitats Directive of the European Union, a favorable conservation status for the brown bear (Ursus arctos) should be targeted at the population level in large contiguous habitats such as the Alps, the largest mountain range in Europe. However, in most of the Alps brown bears are extinct and habitat suitability in these areas is often questionable. For this paper, radio-tracking data from four projects with 42 individual bears was compiled to assess habitat suitability. Discrete-choice models with random bear effects were fitted and compared to results obtained from compositional analysis and logistic regression. Sound definition of the available area in the discrete-choice model turned out to be essential. Brown bears showed a preference for forested and steep habitats and an avoidance of roads.Results from the three approaches were used to predict habitat suitability across the entire range of the Eastern Alps. Minimum potential population size was projected based on observed densities in Trentino and Central Austria, and ranged from 1228 to 1625 individuals, with 518–686 mature bears. This would satisfy a favorable conservation status. The developed methodology also has wide applicability to quantification of habitat suitability and potential population size in other cases where species are at risk.
... Avoidance by bears of the areas of greatest human activity is well known from North America Vander Heyden and Meslow, 1999;Gibeau et al., 2002;Boyce and Waller, 2003;Chruszcz et al., 2003;Johnson et al., 2005;Waller and Servheen, 2005;Rode et al., 2006). Avoidance and low use by bears of areas surrounding major roads and human settlements has been described in numerous studies in recent years from North America, Asia and Europe (Clevenger et al., 1992;Huygens et al., 2001;Wielgus et al., 2002;Kaczensky et al., 2003;Preatoni et al., 2005). Avoidance of human disturbance is also well known for some other species of wildlife, including birds and ungulates (Reijnen et al., 1996;Forman and Alexander, 1998;UNEP, 2001;Nellemann et al., 2003). ...
... Within populations, seasonal home range sizes vary according to age and sex, population density, reproductive status during the mating season, and the occurrence of temporally available congregated foods (e.g. salmon, garbage, army cutworm moths Euxoa auxiliaris; Craighead et al. 1995a, Dahle & Swenson 2003c, Preatoni et al. 2005, Rode et al. 2006, Bellemain et al. 2006a. ...
ABSTRACT1 Research on mating systems and reproductive strategies is valuable for providing ethological knowledge, important for the management and conservation of a species, and in a broader sense, important for biodiversity conservation. 2 We reviewed the literature to document the mating system of the brown bear Ursus arctos. We determined that many aspects of the reproduction of the brown bear remain unclear, including (i) biological aspects, such as hormone and oestrous cycling, sperm competition, mate choice, sexually selected infanticide, etc. and (ii) human impacts on the mating system, occurring when humans alter population size and structure, through, for example, hunting or habitat degradation. 3 We considered three mating system classification frameworks from the literature (Emlen & Oring 1977, Clutton‐Brock 1989, Shuster & Wade 2003) and applied various brown bear populations to them. We did this (i) to document the plasticity of the mating system of the brown bear, and (ii) to find commonalities among the reported mating system classifications in order to provide a general and common classification of the brown bear's mating system. 4 The mating system of the brown bear can, in general, be classed as ‘polygamous’. Subclassifications can nevertheless be valuable on smaller spatial scales. 5 Within the polygamous mating system of the brown bear, biological aspects and human impacts can influence reproductive strategies at the individual and population level. Mating system classification frameworks often lack a common terminology, which contributes to the variety of published classifications of the mating system of the brown bear.
Reintroduced animals—especially those raised in captivity—are faced with the unique challenge of navigating a wholly unfamiliar environment, and often make erratic or extensive movements after release. Naïveté to the reintroduction landscape can be costly, e.g., through increased energy expenditure, greater exposure to predation, and reduced opportunities to forage. Integration with an extant population may provide opportunities for social information transfer. However, in the absence of interactions with residents, it is unclear how individual and social learning may affect an animal’s ability to track resources in an unfamiliar landscape. We use integrated step selection functions (iSSFs) to address these knowledge gaps, by evaluating the extent to which environmental factors, individual experience (time since release), and social information-sharing (group size) influence movement decisions by scimitar-horned oryx ( Oryx dammah ) reintroduced into their native range for the first time in ca. 30 years. We found that both experience and social factors influenced the habitat selection and movement behavior of reintroduced oryx. Of four candidate iSSFs, the model that included environmental, experience, and group size variables performed best in both dry and wet periods. Statistically significant interaction terms between environmental variables and experience were generally larger than similar terms for group size, indicating that experience may affect habitat selection by reintroduced oryx more strongly than social factors. These findings may inform the management of recovering wildlife populations, update widely-held expectations about how released ungulates acclimate to novel landscapes, and demonstrate the utility of long-term monitoring of reintroduced populations.
For successful large carnivore conservation it is important to understand mechanisms how large carnivores adapt to human presence, including anthropogenic environmental modifications. Widespread Holarctic distribution throughout various levels of human-use makes the brown bear (Ursus arctos) an appropriate model species for studying response to anthropogenic effects in large carnivores. We reviewed the literature throughout entire species' range to examine how bears modify their habitat use in response to the intensity of anthropogenic modifications of their environment. Results indicate that bears in general avoid human structures, with strongest avoidance observed for permanently inhabited areas and high-traffic roads. We observed their stronger avoidance of human structures in areas with higher human population densities. Comparison between Europe and North America indicate stronger avoidance of urban areas among European bears, while no obvious differences were observed for other types of anthropogenic infrastructure. We suggest caution when comparing responses among study areas, because most bear habitat-use studies reported only relative habitat selection (i.e. use relative to the availability) and there is lack of reported data on absolute habitat use. Therefore we recommend analysis of original data across the species' range in order to advance our understanding of bear habitat-use across a gradient of intensity of human disturbance.
The Pyrenean brown bear Ursus arctos population in the mountains between France and Spain is one of the smallest and most threatened populations of large carnivores in Europe. We assessed trends in brown bear habitat use in the Pyrenees and investigated the underlying environmental and anthropogenic drivers. Using detection/non-detection data collected during 2008–2014 through non-invasive methods, we developed dynamic occupancy models, accounting for local colonization and extinction processes. We found two non-connected core areas of occupancy, one in the west and the other in the centre of the Pyrenees, with a significant decrease in habitat use overall during 2008–2014. We also found a negative correlation between human density and bear occupancy, in agreement with previous studies on brown bear habitat suitability. Our results confirm the Critically Endangered status of the Pyrenean population of brown bears.
Solid understanding of species’ range and local population densities is important for successful wildlife management and research. Specific behavioural and ecological characteristics make brown bear Ursus arctos a difficult species to study. We present a map of range and local population densities of brown bears in Slovenia made with the use of new approach similar to voting classifications based on a combination of four datasets: GPS telemetry data, records of bear removals, systematic and opportunistic direct observations and signs of bear presence, and non-invasive genetic samples. Results indicate that the majority of bears in Slovenia live in Dinaric Mountains in the southern part of the country where local bear population densities exceed 40 bears / 100 km2. This is one of the highest population densities reported so far for this species worldwide. Population densities decrease towards the north (Alpine region) and are very low along the border with Italy and Austria where almost no females are present. This explains slow past and present expansion of this transboundary bear population into the Alps and should be considered in future bear re-colonization management strategies. Results also showed that data from observations and removals overestimate bear population densities at low values, while mortality and genetic data overestimate population densities in areas with more people. Nevertheless, all data types appeared useful for describing the general bear distribution patterns. Similar approach could be applied to studies of other charismatic or game species, for which several types of data are often available.
1The metapopulation metaphor is increasingly used to explain the spatial dynamics of animal populations. However, metapopulation structure is difficult to identify in long-lived species that are widely distributed in stochastic environments, where they can resist extinctions. The literature on mammals may not provide supporting evidence for classic metapopulation dynamics, which call for the availability of discrete habitat patches, asynchrony in local population dynamics, evidence for extinction and colonization processes, and dispersal between local populations.2Empirical evidence for metapopulation structure among mammals may exist when applying more lenient criteria. To meet these criteria, mammals should live in landscapes as discrete local breeding populations, and their demography should be asynchronous.3We examined the literature for empirical evidence in support of the classical criteria set by Hanski (1999), and for the more lenient subset of criteria proposed by Elmhagen & Angerbjörn (2001). We suggest circumstances where metapopulation theory could be important in understanding population processes in mammals of different body sizes.4The patchy distribution of large (>100 kg) mammals and dispersal often motivate inferences in support of a metapopulation structure. Published studies seldom address the full suite of classical criteria. However, studies on small mammals are more likely to record classic metapopulation criteria than those on large mammals. The slow turnover rate that is typical for medium-sized and large mammals apparently makes it difficult to identify a metapopulation structure during studies of short duration.5To identify a metapopulation structure, studies should combine the criteria set by Hanski (1999) and Elmhagen & Angerbjörn (2001). Mammals frequently live in fragmented landscapes, and processes involved in the maintenance of a metapopulation structure should be considered in conservation planning and management.
We conducted a regional-scale evaluation of landscape permeability for large carnivores in Washington and adjacent portions of British Columbia and Idaho. We developed geographic information system based landscape permeability models for wolves (Canis lupus), wolverine (Gulo gulo), lynx (Lynx canadensis), and grizzly bear (Ursus arctos). We also developed a general large carnivore model to provide a single generalization of the predominant landscape patterns for the four focal species. The models evaluated land cover type, road density, human population density, elevation, and slope to provide an estimate of landscape permeability. We identified five concentrations of large carnivore habitat between which we evaluated landscape permeability. The habitat concentration areas were the southern Cascade Range, the north-central Cascade Range, the Coast Range, the Kettle-Monashee Ranges, and the Selkirk-Columbia Mountains. We evaluated landscape permeability in fracture zones between these areas, including the 1-90 Snoqualmie Pass area, the Fraser-Coquihalla area, the Okanogan Valley, and the upper Columbia and Pend Oreille River valleys. We identified the portions of the Washington state highway system that passed through habitat linkages between the habitat concentration areas and areas accessible to the focal species. This analysis provides a consistent measure of estimated landscape permeability across the analysis area, which can be used to develop conservation strategies, contribute to future field survey efforts, and help identify management priorities for the focal species.
At least 73 European brown bears (Ursus arctos) have been killed by vehicles in the forest region (1500 km 2) of Gorski kotar, Croatia, from 1963 to 1994. Fifty-one (70%) were killed by trains along the Zagreb-Rijeka railway and 22 (30%) were killed by motor vehicles along roadways in Gorski kotar. Several parameters were measured at known collision sites (n = 46) and at an appropriate number of random sites (n = 61) along roads and railroads. Slope angle and length, as well as longitudinal and perpendicular visibility at accident and random sites were not significantly different. We concluded that microsite topography had little or no influence on the occurrence of bear traffic accidents. Instead, food sources related to human activities, such as garbage along roads, may have served as local attractants to bears and were found near at least 15 (33%) accident sites, but at only 5 (8%) of the random sites. We found that 3 main corridors for bear movements were cut by traffic lines. Provisional mitigation measures were proposed to reduce conflict between bears and traffic, and an artificial tunnel or green bridge (100.5 m long) was added to a new highway project.
Bears preferred forested habitats and used beech Fagus sylvatica and durmast (Quercus petraea)/pyrenean (Q. pyrenaica) oak forests in greater proportion than their availability. The most critical area for bears was a multi-community complex of deciduous forest/shrub/grassland between 1100-1400m, situated above areas of intense agricultural activity but below the subalpine zone. -from Authors
Theoretical and empirical research indicates that territoriality is related to habitat productivity. Female black bears (Ursus americanus) exhibit intrasexual territoriality in northern North America where habitat productivity is low. However, telemetry studies show that adult female black bears in the Southern Appalachian Mountains, where productivity is higher, exhibit considerable home range overlap. This overlap was quantified using an index that weighs home range overlap by the extent that 2 bears share parts of their home ranges. Home range of adult females overlapped extensively during each year and season. Females who reached sexual maturity established home ranges close to their mothers or took over their mothers' home ranges if their mothers had died. The importance of sample size and statistical and biological independence of bear locations to home range analysis is unclear. Int. Conf. Bear Res. and Manage. 7:235-242 Burt (1943) clarified the terms territory and home range as applied to mammals. He defined a mammal's home range as "the area ... over which the animal normally travels in search of food" (1943:351), and defined territory as "any defended area" (1943:346). Since then, home range analysis has become impor- tant to field research on mammals, especially carni- vores, and home ranges have been studied from many approaches (e.g., Waser and Jones 1983, Bekoff and Mech 1984, Harrington and Mech 1984, Hemker et al. 1984, Laundre and Keller 1984, Liberg 1984, Lima 1984, Stamps 1984). However, because an animal's home range is easier to conceive than to map and because different researchers have had different in- terests, researchers have used a variety of definitions more precise than Burt's to facilitate mapping and description. Not all of these definitions are equivalent, and some may even be inappropriate for methodo- logical or statistical reasons (Bekoff and Mech 1984, Laundre and Keller 1984, Swihart and Slade 1985). The concept of territory has undergone even more evolution than has that of home range. In general, an individual or a group of animals is now considered to be territorial when it has exclusive use of an area or resource with respect to other members of its spe- cies. The potential effects of territoriality on popu- lation regulation have received considerable theoretical attention (Brown 1969, Fretwell and Lu- cas 1969, Watson and Moss 1970, Maynard Smith 1974) and territory size appears to be the most critical factor. A predominant determinant of territory size is food and in general increased availability of food leads to decreased territory size (Ebersole 1980, Hixon 1980, Schoener 1983). Under some conditions, increased food availability affects territory size in- directly through increased trespassing (Myers et al. 1979). Increased food availability may also lead to a breakdown of territorial behavior altogether (Car-
Proposes a set of hypotheses to predict under what conditions females and males should defend territories. 1) Microtines have a low-quality diet and should tend to be food-limited. Females invest a large portion of their energy in reproductive physiology, and their reproductive success should be limited by their ability to acquire food and convert it into weaned offspring. Males invest much less energy in reproductive effort and do not participate in parental care; thus, their reproductive success should be limited by access to females. Territoriality in females should thus be food-based, that in males, female-based. 2) There are 3 main dietary categories for microtines; fruit-seed-fungus, forbs, and grasses. In general, fruits and seeds (in forest habitat) and forbs (in meadows) are patchily distributed, relatively sparse and poorly renewable. Since patchy distribution of a resource increases its defensibility, and since sparseness and poor renewability increase the costs of allowing exploitation by intruders, females relying on these 2 diets should be territorial. Grass in meadows is evenly distributed, abundant and highly renewable. Thus, females of species that rely largely on grasses should be nonterritorial. 3) When females are territorial they tend to be hyperdispersed; when females are nonterritorial they should be clumped in distribution. Since evenly spaced females are difficult to defend, males territoriality should not occur in species showing female territoriality. Conversely, when females are nonterritorial, males should be territorial. -from Author
Twenty six Ursus arctos were captured, radio-collared, and tracked in and around Plitvice Lakes and Risnjak National Parks. The largest male and female ranges were 224 km 2 and 147 km 2, respectively. Mean annual ranges were 128 km 2 and 58 km 2, respectively. Male ranges were 2-5 times larger than female ranges. The median straight-line distance between consecutive day locations was 1.5 km for all bears and the maximum distance was 8.5 km. Distances traveled daily by males and females were similar, but movements of females were restricted to smaller areas. Winter ranges were significantly smaller than ranges during other seasons. -from Authors
The size of the home range is examined in mammals. It is determined, mainly, by the amount of energy expended by the species, and, therefore, the home range area may vary according to the direct and indirect influences of weather and climate on the animal. But the kind of food that is utilized will also influence home range size. Those species that must hunt for their food need larger areas for food gathering than those species that feed on the vegetation. As a result the largest hunters appear to have their food habits regulated by considerations of the efficient use of the food materials in their home range. Finally, the home range size affects population density, which in turn influences the behavior in the population.
Area of home range (H) can be related empirically to body weight (W) by the formulation H = aW^k. The computed values of exponent k have generated controversy concerning potential differences between trophic groups and whether they differ from 0.75 (the value expected if area of home range is a function of basal metabolic rate). When large mammals are considered, the empirical relationship assumes the form H = .002W^1^.^0^2 for herbivores, H = .059W^.^9^2 for omnivores, and H = .11W^1^.^3^6 for carnivores. By treating the animal's energetic requirements and the productivity of its habitat explicitly, empirical values of k > 0.75 are shown to result from declining rates of production of utilizable energy per unit area of habitat with increasing body weight. While trophic status and weight modify the utilizable proportion of energy in the habitat, broad correlations also exist between size of home range and surrogate variables for productivity (precipitation and latitude). Differences in weight alone account for a large portion of the differences between male and female or subadult and adult home ranges. Behavioral phenomena need not be invoked. Differences between herbivores and carnivores are in the direction suggested for birds and mammals. Criticisms regarding inter-class and inter-tropic comparisons appear resolved.
The diet of the European brown bear (Ursus arctos) was studied in the Cantabrian Mountains, Spain, by analyzing the frequency of occurrence and percent volume of 929 feces collected 1983-1988. Plant material was the predominant food during spring and summer (84.1 and 44.8% of total volume, respectively) until more nutritious foods became available. During autumn and winter, hard mast formed the greatest part of the diet constituting 61.5 and 49.9% of the total volume, respectively. Livestock and wild ungulates were supplementary foods for bears, usually obtained by scavenging rather than predation. Insects were consumed year-round, ranging from 19.5% volume in summer to 0.1% in winter. Remnant deciduous forests and upland creek drainages were prime feeding areas of bears.
IUCN categories of threat (Endangered, Vulnerable, Rare, Indeterminate, and others) are widely used in "Red lists' of endangered species and have become an important tool in conservation action at international, national, regional and thematic levels. The authors present proposals to redefine categories in terms of the probability of extinction within a specific time period, based on the theory of extinction times for single populations and on meaningful time scales for conservation action. Three categories are proposed (critical, endangered, vulnerable) with decreasing levels of threat over increasing time scales for species estimated to have at least a 10% probability of extinction within 100 yr. -from Authors
At least 73 European brown bears (Ursus arctos) have been killed by vehicles in the forest region (1500 km^) of Gorski kotar, Croatia, from 1963 to 1994. Fifty-one (70%) were killed by trains along the Zagreb-Rijeka railway and 22 (30%) were killed by motor vehicles along roadways in Gorski kotar. Several parameters were measured at known collision sites {n = 46) and at an appropriate number of random sites {n = 61) along roads and railroads. Slope angle and length, as well as longitudinal and perpendicular visibility at accident and random sites were not significantly different. We concluded that microsite topography had little or no influence on the occurrence of bear traffic accidents. Instead, food sources related to human activities, such as garbage along roads, may have served as local attractants to bears and were found near at least 15 (33%) accident sites, but at only 5 (8%) of the random sites. We found that 3 main corridors for bear movements were cut by traffic lines. Provisional mitigation measures were proposed to reduce conflict between bears and traffic, and an artificial tunnel or green bridge (100.5 m long) was added to a new highway project. Ursus 10:167-171
The brown bear (Ursus arctos) population in Croatia is a possible source of bears for reintroducing and augmenting disappearing European brown bear populations in western Europe. For successful reintroduction, knowledge about bear habitat quality of both source and target areas is necessary. We developed a habitat suitability index (HSI) model to assess European brown bear habitat quality in Gorski kotar, Croatia. Important habitat variables included seasonal foods, cover, roads, and fragmentation. Food sources were available year-round, whereas foraging and denning cover were more limited. Human influence was manifested through a relatively high density of roads (1.91 km/km 2), which included forest roads. Habitat fragmentation did not occur within the study area, but a highway under construction was a possible threat. The overall HSI value of 0.42 for the entire area indicated that brown bear habitat in Gorski kotar is average. Brown bear habitat could be improved with changes in management practices such as closing forest roads, seasonally avoiding logging in denning areas, and reducing reforestation of beech-fir (Fagus sp -Abies sp.) areas to spruce (Picea abies).
The behaviour of eight radiotagged red squirrels (Sciurus vulgaris Linnaeus, 1758) reintroduced at Parco Groane, northern Italy, was monitored for two months following their release. Both male and female squirrels moved over considerable distances the first two weeks after introduction, exploring the new habitat. Two types of exploring behaviour were observed: (i) gradually expanding the home range, moving only short distances each day; and (ii) making regular excursions of more than 1 km followed by short periods of activity in a small area. The latter behaviour resulted in very large home ranges during the exploring phase. After the initial exploring, home range size decreased and one male and two female squirrels changed their space use by increasing the number of activity centres (core‐areas) within their home range. Post‐settlement home ranges were spaced out over the available habitat and all squirrels used almost completely exclusive core‐areas. Only four red squirrels (two males and two females) survived long enough to be the potential founders of the new population that established itself at Parco Groane. We discuss methods to decrease post‐release mortality in red squirrels and consider genetic and demographic consequences of squirrel reintroductions.
Overhunting reduced Eurasian Beaver (Castor fiber) populations to c. 1200 animals, in eight isolated populations, around the end of the 19th century. Protection, natural spread and reintroductions led to a powerful recovery in both range and populations during the 20th century, which continues at a rapid pace. The minimum population estimate is 593 000. There are also c. 12 500 North American Beaver (C. canadensis) established in Finland and Russian Karelia; however, other populations of C. canadensis introduced in Austria, Poland and France ap-pear to be extinct. Castor fiber is now established throughout Europe with the exception of the British Isles, Iberia, Italy and the southern Balkans; reintroductions are continuing. Considerable further expansion in range and population, especially in western Europe and the lower Danube basin, can be expected. If current trends continue, C. fiber will, within a few decades, be a fairly common mammal in much of Europe. Following initial recolonization, populations typically show a pattern of rapid range extension within a watershed, followed only later by rapid population growth, and a barrier effect of watershed divides, which can be strongly isolating where physical or habitat barriers (such as mountains or intensive farmland) intrude between watersheds. Management of beaver distribution should therefore operate at the watershed scale, except where large human-made dams form significant bar-riers to spread. The period of rapid population increase, if unchecked, leads to a phase of population decline as marginal habitats are occupied and exhausted. This coincides with a peak in conflicts with human land-use interests. A regulated hunting take of healthy beaver populations is recommended as the optimal management regime in managed landscapes. Early provision of interpretation and public viewing opportunities has been a feature of several recent reintroductions. This provides a benefit to the local economy through wildlife tourism, and helps foster positive attitudes to beavers.
Kernel density estimators are becoming more widely used, particularly as home range estimators. Despite extensive interest in their theoretical properties, little empirical research has been done to investigate their performance as home range estimators. We used computer simulations to compare the area and shape of kernel density estimates to the true area and shape of multimodal two-dimensional distributions. The fixed kernel gave area estimates with very little bias when least squares cross validation was used to select the smoothing parameter. The cross-validated fixed kernel also gave surface estimates with the lowest error. The adaptive kernel overestimated the area of the distribution and had higher error associated with its surface estimate.
Over the past ten years the scientific basis for reserve selection and design have rapidly developed. This period has also been characterized by a shift in emphasis toward large spatial and organizational scales of conservation efforts. I discuss the evidence in support of this shift toward larger scale conservation by contrasting the success of fine-filter (genes, populations, species) conservation and coarse-filter (communities, habitats, ecosystems, landscapes) conservation. Conservation at both organizational scales has been successful and merits continued support, although fine-filter conservation is more straightforward. Ecological theory suggests that conservation at large scales is preferred. Despite this preference, both fine- and coarse-filter conservation objectives have been met by small reserves. In many landscapes there are no opportunities for the conservation of native species diversity that encompass a large spatial scale. Thus, reserve selection at any organizational scale may include conservation at a variety of spatial scales. A variety of methods have been suggested that integrate across scales of conservation. Some, such as umbrella, flagship, and indicator species, remain very problematic. Reserve selection algorithms and gap analyses, in contrast, offer promising opportunities to increase the efficiency of conservation at all scales.
Home range size, range use and range overlap of adult male and female red squirrels in a coniferous and a deciduous woodland were studied using radio-telemetry. Hypotheses, concerning (1) resource predictability and territorial behaviour, and (2) sex-related and habitat-related differences in spacing strategies were tested. In both habitats males had larger home ranges than females. Range size varied seasonally, tending to increase in April–June and to decrease in winter. Both males and females had intensively used core-areas (70% of all locations) that were much smaller than their total range. Dominant males had larger ranges than subordinates, and male body weight was positively correlated with home range size. For females, range size was inversely correlated with food abundance (coniferous area) or local density (deciduous area). Core-area overlap within a sex was smaller than that between sexes. Dominant females defended exlusive core-area overlap within a sex was smaller than that between sexes. Dominant females defended exclusive core-areas against other females, while subordinates behaved as floaters or settled on the edges of the ranges of dominant females. In the deciduous woodland squirrels had larger home ranges, used significantly larger and more strongly overlapping core-areas and were more tolerant of conspecifics than in the coniferous woodland. The results support the hypotheses that (1) the predictability in time and space of food resources, and (2) sexual differences in key resources used to increase reproductive success in mammals with promiscuous or polygynous mating systems, cause differences in spacing behaviour between habitat types and between adult males and females.
The Ljubljana–Razdrto highway and the parallel Ljubljana–Trieste railway cut through critical brown bear (Ursus arctos) habitat in south-central Slovenia. These high speed, high volume traffic axes are located close to the main dispersal corridor for bears from the Dinaric Mountain range into the Alps. We analyzed radiotracking data of 15 individual bears that lived within 10 km of the highway, compared transportation related and overall known bear mortality, and analyzed the spatial distribution of bear–vehicle accidents. The highway posed a home range boundary to resident bears, but was not an absolute barrier. Transportation-related mortality was high in the vicinity of the highway and railway, and averaged 31% of the total known local mortality from 1992 to 1999. At present the detrimental impact of transportation routes on the bear population in Slovenia is modest due to the high density of bears and the low density of highways—but new highways are planned or already under construction. Managers have to be aware that, due to bears large home ranges and long dispersal distances, a single highway affects bears from a huge area—emphasizing the importance of international cooperation and a landscape approach in highway planning.
The western barred bandicoot was reintroduced to the Australian mainland in 1995 after an absence of at least 60 years. The new population was derived from 14 animals, reintroduced to Heirisson Prong from Dorre Island in Shark Bay, Western Australia. Introduced predators (the European red fox and the feral cat) were controlled at the reintroduction site, but European rabbits were not. A large fenced area of natural vegetation within the reintroduction site was used as a secure refuge from mammalian predators. Bandicoots were released from this predator refuge to the 12 km2 conservation site. Dispersal from the point of free release was minimal. The reintroduced population has persisted for 4 years and increased, with at least 175 bandicoots recruited to the population in this time. The recapture rate of marked bandicoots was low, suggesting that adult mortality was high. Reproductive output at Heirisson Prong appeared greater than that of the two surviving wild populations on Bernier and Dorre Islands. Litter size was similar, but there was an extended annual breeding season at the reintroduction site. Body condition of reintroduced and wild bandicoots were similar, although there was some indication that reintroduced males may have been in poorer condition than their island counterparts. The litter size of bandicoots increased with a decrease in rabbit abundance, however, bandicoots were able to reproduce, maintain condition, and sustain recruitment to allow the population to increase despite the presence of rabbits. Two fox incursions occurred during the 4-year period of establishment, and feral cats were present on occasion in low numbers. Feral cats may be responsible for a lower rate of population increase than that observed on predator-free Dorre Island. Ongoing predator control is essential for any mainland reintroduction of bandicoots.
The demography of red squirrels Sciurus vulgaris removed from three different source areas and reintroduced between February 1987 and January 1988 in an urban park near Antwerp, Belgium was monitored for six years. Animals that were used to human presence had a higher initial survival than those not accustomed to human disturbance. Contrary to our predictions, woodland structure at the removal site did not affect a squirrel's settlement success, and post-release survival of subadults was not higher than that of adults. Only three (33%) introduced males, and five (50%) females survived to produce offspring. Reproductive rate was density-dependent and tended to increase with food abundance (tree seed crop of beech and oak). Consequently, population growth was high the first three years (low density) and decreased after 1990 (high density), when both adult and post-breeding densities (0·8–0·9 squirrels/ha) remained stable, suggesting the reintroduced population had reached its equilibrium density. We discuss some guidelines to increase the success of red squirrel reintroduction projects.
Informed management of large carnivores depends on the timely and useful presentation of relevant information. We describe an approach to evaluating carnivore habitat that uses pre-existing qualitative and quantitative information on humans and carnivores to generate coarse-scale maps of habitat suitability, habitat productivity, potential reserves, and areas of potential conflict. We use information pertinent to the contemplated reintroduction of grizzly bears Ursus arctos horribilis into central Idaho to demonstrate our approach. The approach uses measures of human numbers, their estimated distribution, road and trail access, and abundance and quality of bear foods to create standardized indices that are analogues of death and birth rates, respectively; the first subtracted from the second indicates habitat suitability (HS). We calibrate HS to sightings of grizzly bears in two ecosystems in northern Idaho and develop an empirical model from these same sightings based on piece-wise treatment of the variables contained in HS. Depending on whether the empirical model or HS is used, we estimate that there is 14 800 km2 of suitable habitat in two blocks or 37 100 km2 in one block in central Idaho, respectively. Both approaches show suitable habitat in the current Evaluation Area and in an area of southeastern Idaho centered on the Palisades Reservoir. Areas of highly productive habitat are concentrated in northern and western Idaho and in the Palisades area. Future conflicts between humans and bears are most likely to occur on the western and northern margins of suitable habitat in central Idaho, rather than to the east, where opposition to reintroduction of grizzly bears is currently strongest.
In recent years, the European wolf (Canis lupus) population has expanded its southern range from the Italian Peninsula to the Maritime Alps (Italy and France) and to Piemonte (Italy); establishing small sub-populations. Hence re-colonisation of the Swiss Alps is now likely to occur. In 1995–1996 the wolf reached the southern part of Switzerland (Canton of Valais) from where he got extinct 150 years ago. Actual conflicts of interests between livestock breeders, local political authorities and nature conservation parties, as well as federal authorities defending the protected status of wolf, require serious management investigations.
Despite numerous, generally unsuccessful attempts to reintroduce threatened Australian mammals, the factors leading to their failure have not been fully clarified, although predator control would appear to be of paramount importance. An experimental approach was taken in attempting to establish a population of bridled nailtail wallabies in an area of apparently suitable habitat and low fox density, but on the edge of the species’ former range. The 133 wallabies released since late 1996 comprised four groups: captive-bred animals, wild caught from the single remaining wild population, animals that were captive bred and acclimatised at the translocation site in a 10 ha predator-proof enclosure, and animals which had been bred in the enclosure. Survival was highest in those bred in the enclosure and highly variable among captive-bred animals. Survival estimates for wild recruits suggested the population would maintain a positive rate of increase under prevailing environmental conditions. Spotlighting surveys suggested the population had increased to approximately 400 animals by late 1999. Above average rainfall during 1996–1999 and no apparent predation suggests caution in describing the translocation as a success. Ongoing monitoring is critical, because it is uncertain how the population will cope with drought and inevitable predation events, and whether the population will expand and persist outside of limited preferred habitat.
Data presented in this paper suggest that a complex interaction occurs between the physiological parameters of mammals and the growth and fluctuation of their populations: The Malthusian parameter rm increases with rate of metabolism, which in turn varies with body size and food habits. It can be concluded that it behooves all mammals to have as high a rate of metabolism as can be sustained by the quantity and quality of their food resources in space and time, because this adjustment will permit them to maximize their reproductive efforts. These interactions raise many questions, one of which concerns the temporal variation in reproductive strategies. Thus, Coady (1975) showed that the basal rate in the brown lemming (Lemmus trimucronatus) may be especially high during a winter in which the snow cover is reduced. Does a seasonal variation in the rate of metabolism therefore have a significant influence on seasonal variation in reproduction and therefore in population size? Whatever the correct answer to t...