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Conservation of large carnivores in protected areas with high human use or habitation is challenging due to ecological, political and socioeconomic factors. Understanding underlying patterns of human–carnivore interactions is vital for their conservation. We investigated patterns and costs of livestock depredations by common leopards Panthera pardus in and near Pir Lasura National Park, Pakistan, using standardized questionnaires to collect data from 133 respondents during 2014–2015. Respondents lost 209 animals to leopard attacks, primarily goats (78.5%), followed by dogs (11%). Most leopard depredations of livestock occurred during the day, with almost 60% occurring during 9:00–11:00 h and 14:00–16:00 h. Greatest numbers of livestock killed was during May–July (60.9%) followed by December (9%). Most attacks occurred when livestock were not guarded (48.9%) and fewest when guarded by humans and dogs (2.3%). Most livestock depredations occurred in larger herds of ≥ 20 animals (58%). Respondent's perceptions of leopards were negative, with most (79.7%) stating their unwillingness to conserve leopards. Eight leopards were reportedly killed in retaliation to livestock. Livestock depredations by leopards represented almost 9% of the annual income of respondents. Our study provides several insights to mitigate human leopard conflict including use of humans and dogs to guard livestock during times of peak vulnerability (e.g. late morning and during summer, May–July). Further, improved corrals could reduce access to livestock by leopards and local communities should be aware of more effective corral designs. Reducing livestock depredations and corresponding economic losses could improve perceptions of local communities and promote tolerance towards leopards, reducing retaliatory killing and facilitating coexistence.
Stimuli perceived as stressful by animals increase glucocorticoid secretion over basal levels. This is an adaptive response that by altering energy metabolism and animal behavior facilitates survival during acute stress. Secretion of corticosterone increases in adult insectivorous bird species after a short period of adverse weather conditions, which may determine a decreased availability of insect prey as well as thermoregulatory stress. Hormone response to stress in altricial nestlings is not yet clear. In some species (e.g. northern mockingbird, white-crowned sparrow) early age nestlings show a reduced or null response to stress stimulation, and the hypothalamus–pituitary–adrenal (HPA) axis seems to be fully active only at an age close to independence. In other species (e.g. barn swallow, canaries) the HPA axis seems to be active even in young nestlings. However, most of the data refer to experimentally induced stress while the physiological response to natural environmental perturbations has been scarcely investigated. The main aim of our study was to evaluate corticosterone secretion response to short periods of adverse weather conditions in two different age groups of barn swallow nestlings (7–14 days old and 15–21 days old). Furthermore, stress responses were compared between medium aged nestlings, late aged nestlings and adults, to understand whether HPA axis activity changed with age. A fecal non-invasive hormone assessment method was used.
Our results showed that during adverse weather conditions, insect abundance decreased and corticosterone metabolites levels increased significantly and to a similar extent in droppings of medium and late aged barn swallow nestlings as well as in adults. Our data support previous findings, that the HPA axis is already fully functional in 7–14 days old nestlings. Further studies are required to verify the existence of a hyporesponsive period in younger barn swallow nestlings.
Hustai National Park in Mongolia became a refuge for takhi Equus ferus przewalskii, a wild horse native to central Asia, in 1992. Wild takhi became extinct in the wild in the 1960s, although there was a small captive population in European zoos that was used to repopulate Hustai National Park. This park is also inhabited by red deer Cervus elaphus, which may compete with takhi for food. We analyzed the fecal composition and habitat use of takhi and red deer. Takhi mainly foraged on grasses in the steppe, while red deer foraged on grasses and dicots in the forest. The percentage similarity (PS) of foods was 65% in summer and 58% in winter. There does not appear to be competition for food or habitat between these species because both diets and the habitat selection were different. We discuss some management implications and emphasize the importance of integrated management of the refuge.
Gunshots are a worldwide source of anthropogenic disturbance, and knowledge about the potential effect on wildlife is central for conservation and sustainable management of affected species. This study contributes novel insight of the response behaviour and effect of gunshot disturbance on one of the most culturally important seabird species of the Arctic, the thick-billed murre (Brünnich's guillemot, Uria lomvia). We studied effects of gunshot disturbance at breeding colonies to explore the distance where effects started, the difference in the behavioural response between presumed disturbed colonies (e.g. by traffic and hunting) and largely undisturbed colonies, and among plots with varying seabird densities. We carried out two different types of controlled gunshot experiments – one measuring the distance at which murres first reacted to gunshots (flight initiation distance, ‘FID') and one measuring the proportion of murres remaining in the colony during and after repeated gunshots (20 gunshots within 78 min). FID varied from 0.5 to 5 km. The proportion of murres remaining in the plot after the repeated gunshots ranged from 0.44 to 0.8. Mainly murres not attending offspring took off when disturbed by gunshots, but occasionally also birds incubating their egg or brooding their chick took off. We found that density of seabirds (murres and black-legged kittiwakes Rissa tridactyla) at the plot area scale was the best explaining factor for FID, and to some extent also for the effect of repeated gunshots, both for disturbed and undisturbed colonies. Murres in denser colonies reacted earlier (had larger FIDs) and somewhat more strongly (higher proportions fleeing) to gunshots than murres in less densely populated colonies. FID clearly showed that the current legislation in Greenland regulating gunshots near breeding colonies is insufficient. We provide some recommendations for improved management of a popular game species under pressure.
Goose management in Europe is faced by multiple challenges, as some species are declining and in need of conservation actions, while other populations have become very abundant, resulting in calls for increased harvest. Sweden has long-term series of harvest data and counts of breeding and autumn-staging geese. We used national data (indices) for greylag goose, bean goose and Canada goose to study shifts in temporal trends and correlative patterns, and to infer possible causal links between harvest and population trends. Our study provides an opportunity to guide management given the data collected within the present monitoring, as well as to suggest improvements for future data collection. The populations of greylag and Canada geese increased in Sweden 1979–2018, but this long-term trend included a recent decrease in the latter species. Bean goose breeding index decreased, whilst staging numbers and harvest varied with no clear long-term trend. For Canada goose, our analysis suggests that harvest may affect population growth negatively. For bean goose and greylag goose we could not detect any effect of harvest on autumn counts the following year. We find that the present data and analysis of coherence may suffice as basis for decisions for the current management situation in Sweden with its rather unspecific goals for greylag (very abundant) and Canada goose (invasive species) populations. However, for management of bean geese, with international concerns of over harvest, data lack crucial information. For future management challenges, with more explicit goals, for all goose species we advocate information that is more precise. Data such as hunting effort, age-structure of goose populations and mark–recapture data to estimate survival and population size, is needed to feed predictive population models guiding future Swedish and European goose management.
The problem we address is motivated by the desire to regulate the size of the NW/SW European population of greylag geese Anser anser to meet a number of management objectives, including providing sustainable harvests and minimizing agricultural impacts and conflicts. Using simple models of population dynamics along with observed allometric relationships in birds, we have concluded that reported estimates of greylag goose population size and/or offtake at the flyway level are likely biased, perhaps severely so. Recognizing that resources are limited, we suggest that the most pressing need may be to investigate and strengthen monitoring protocols for offtake. We also describe a simple information-gap (‘info-gap') decision model that could allow decision makers to make informed choices about changes in offtake until such time that more reliable monitoring information is available for greylag geese. With the info-gap decision model we were compelled to use a management criterion based on the growth rate of the flyway-wide population because true levels of abundance and offtake are unknown. Moreover, we emphasize that in the face of deep uncertainty about greylag goose abundance and offtake, decisions concerning management of the population carry a high risk of failing to meet conservation objectives, whatever they may be. While the info-gap analysis suggests an increase of offtake beyond the nominal level of 450 000 reported in the International Single Species Management Plan may be necessary to stabilize the population, we do not know the current level of offtake (i.e. whether it has recently changed from that last reported). Moreover, recent counts conducted by the range states and the International Waterbird Census suggest that the winter flyway population may no longer be increasing. For these reasons, management implications of the info-gap analysis must be viewed with caution.
Wildlife managers and researchers need to understand the status of the wildlife populations they are trying to conserve. Though various methods have been developed to monitor wildlife in their natural habitats, the complexity and accessibility of most techniques often limit their usability. Such techniques often take significant resources and time to deliver results, and methodological noncompliance may lower the reliability of results. Given this need to study wildlife populations reliably, quickly and within financial and human resource constraints faced by wildlife managers, we assessed the reliability and effort required to carry the pooling local expert opinion (PLEO) method as articulated by Hoeven et al. (2004). We did this by comparing density estimates of several wildlife species derived by following the PLEO method with those estimated using a conventional method along with results from the literature on wildlife monitoring studies from Bornean rainforests. Our analysis shows that the PLEO methodology provides an effective and complementary tool to estimate wildlife densities in tropical rainforests. We suggest that by incorporating the PLEO methodology into regular monitoring activity, conservation NGOs can create a platform that allows for participatory wildlife monitoring and create the platform to involve local communities in biodiversity conservation.
American woodcock Scolopax minor (hereafter woodcock) migration ecology is poorly understood, but has implications for population ecology and management, especially related to harvest. To describe woodcock migration patterns and phenology, we captured and equipped 73 woodcock with satellite tracking devices in the Central Management Region (analogous to the Mississippi Flyway) of North America and documented migration paths of 60 individual woodcock and 87 autumn or spring woodcock migrations during 2014–2016. Woodcock migration at the scale of the Central Management Region was more synchronous in spring than in autumn, but unlike most other migratory birds, average duration of autumn migration (31 days) was shorter than duration of spring migration (53 days). This difference in migration duration resulted from woodcock making more close-together migratory stopovers during spring migration, not because woodcock had individual stopovers of longer duration. During autumn migration, the number of days, the number of stopovers, migration end date and net migration displacement were negatively related to initiation date and rate of migration, and the number of stopovers and the net migration displacement were negatively related with migration end date. Spring migration duration, end date, the number of stopovers and net migration displacement were negatively related to migration rate and initiation date was positively related to migration rate, suggesting that woodcock that initiated spring migration later had faster migration rates. Juvenile female woodcock began spring migration later than adult female woodcock. Our results provide a basis for comparing current harvest seasons with presence of migrating woodcock during autumn and provide insight into differential harvest of migratory versus local woodcock on breeding areas.
Encroachment by woody invasive plants has been recognized as a major driver of structural change in grasslands ecosystems. The impact of invasive plant-mediated changes on mammalian species from higher trophic levels is relatively less understood. This study aims to understand the impact of woody encroachment on the ecology of a relatively understudied mesopredator, the Indian desert fox Vulpes v. pusilla in a semi-arid saline grassland ecosystem in Western India. We examined the site occupancy of the Indian desert fox at the landscape level, and den site selection at the micro-habitat scale. We also examined the diet of desert foxes during winter and summer season. We found that at the landscape level the desert fox selects more open Suaeda saline habitats over dense invasive Prosopis juliflora dominated habitats. At the scale of the den, proximity to water and vegetation cover were the main drivers of den site selection. Similar to other arid zone foxes, insects, plant materials and small mammals were the main components of the diet of Indian desert fox. Given its selection of open habitats, invasive shrub encroachment is likely to result in a loss of habitat as well as resources for this species, potentially impacting on the conservation status of this already range-restricted species in India.
Increasing free-ranging cat populations are a cause of concern for wildlife management and biodiversity conservation. Cats carry and transmit multiple diseases, annually depredate billions of birds and mammals in the mainland United States, and have caused extinctions and declines of wildlife populations worldwide. Trap–neuter–return (TNR) efforts, which entail trapping, sterilizing and releasing unowned free-ranging cats with the goal of reducing populations, have been implemented globally despite limited evidence of their ability to reduce cat numbers. To assess the effectiveness of a TNR program initiated in 2013 in Stillwater, Oklahoma, USA, we used trail cameras at 15 locations to estimate changes in cat abundance and the percentage of ear-tipped (i.e. sterilized) individuals between 2014 and 2018. We reviewed photographs to identify individual cats, and after accounting for detectability with mark–resight analyses, we estimated a non-significant decrease in abundance from 62 to 48 total cats across sampled locations. In 2018, approximately 27% of cats were ear-tipped compared to 0% in 2014, yet this percentage remains far below estimated sterilization levels needed for TNR to reduce unowned cat populations. Although additional long-term monitoring is needed, our results suggest that TNR conducted at its current intensity is unlikely to reduce Stillwater's cat population. Our research adds further evidence to the growing body of scientific literature indicating that TNR is ineffective in reducing cat populations.
Water-filled tree holes (WHs), commonly referred to as dendrotelmata, develop when water accumulates in cavities related to tree architecture or in rotten parts of the tree. These structures can occur in forest ecosystems and may represent essential microhabitats in the life cycle of various animal species. WHs form temporary microhabitats during wet periods and sometimes sustain water throughout dry seasons. Research on the use of WHs by organisms mainly focuses on invertebrates developing in these while vertebrates are rarely mentioned. A literature search on the use of WHs by vertebrates revealed that attention has been given only to vertebrates in tropical and subtropical systems, mostly to groups with aquatic stages, such as amphibians. To fill the knowledge gap on the use of WHs by vertebrates in temperate forests, we conducted a camera study in three sites across Germany. We identified a total of 28 vertebrate species including 11 mammal, 17 bird and one amphibian species using the WHs. The recorded videos showed that vertebrates use the WHs mainly for nutrition and hydration. With an expected future increase in frequency and intensity of dry spells in central Europe, these microhabitats may sustain healthy forest ecosystems by providing resources for wildlife. Reliable, updated data about the importance of WHs for vertebrates is required to urge forest managers and stakeholders to enforce the preservation of these microhabitats.
The zone of influence (ZOI) is the area in the vicinity of industrial development where avoidance by caribou Rangifer tarandus or other wildlife species is observed. Here we examine ZOI around two diamond mines in the Northwest Territories (NWT), Canada from 1998 to 2017. In this paper, we further develop segmented/piecewise regression methods to analyze collar location and aerial survey data with a focus on yearly trend in ZOI for the Bathurst caribou herd. A base habitat model was initially formulated to account for habitat selection around mines followed by estimation of ZOI distance and magnitude. Seasonal ranges of the herd contracted from 2009 to 2017 due to decline in herd size, which influenced the distribution of caribou relative to the mines as well as larger scale habitat selection. Models with year-specific estimates of ZOI were more supported than models assuming a constant ZOI across years. Significant ZOI's occurred for aerial survey and/or collar data in 9 of 15 years from 2003 to 2017 when both mines were in full operation, with ZOI distances ranging from 6.1 to 18.7 km. Non-significant ZOI's occurred from 1998 to 2002 before both mines were fully operational. Caribou were attracted to lakes in drought years which significantly influenced distribution relative to mines as well as the magnitude of the ZOI detected. The ZOI extent averaged 7.2 km (CI = 3.8–10.5) when standardized for mean levels of drought. Our analysis suggests that ZOI varies both annually and spatially because of the location of mines relative to habitat selection and seasonal range size. Therefore, exacting analysis methods that account for these sources of variation are required for robust ZOI estimates. Segmented regression methods have become available in the R statistical program that allow flexible ZOI estimation for implementation of the methods in this study for caribou or other wildlife species.
Camera traps are widely used to collect information on the distribution and abundance of multiple species simultaneously. However, we still lack important guidance for designing camera-trap surveys to monitor multiple species, and the consequences of species-specific responses to survey design strategies are often overlooked. Using camera-trap data collected on ten medium-to-large North-American carnivores in northern Minnesota, USA, between 2016 and 2018 (23 337 active trap-days), we evaluated: 1) two different survey-design frameworks (random- versus road-based), 2) two different lure types (salmon oil versus fatty acid scent oil), 3) two different placement strategies (completely random versus randomly-selected sites with feature-based placement), 4) survey timing (spring versus fall) and 5) temporal trends in daily encounter probabilities. Using generalized linear mixed models, we found evidence of differential responses to all of these design strategies. For 9 out of 10 species, we found strong responses to survey design frameworks: red foxes Vulpes vulpes, coyotes Canis latrans, bobcats, Lynx rufus, striped skunks Mephitis mephitis, wolves C. lupus and gray foxes Urocyon cinereoargenteus, had estimated encounter frequencies that were 9- to 106-fold higher at unlured sites along secondary roads; black bears Ursus americanus, martens Martes americana and fishers Pekania pennanti had estimated encounter frequencies that were 15- to > 3600-fold higher at lured, randomly selected sites. For six species, salmon oil provided 2- to 4-fold more encounters than fatty acid scent oil, but feature-basedplacement only improved detections of fishers. Daily encounter probabilities differed between spring and fall for all species, and usually decreased slightly within each sampling period Our study confirms that even similar-sized or closely-related species respond differently to survey-design choices. To maximize encounter frequencies, we recommend that multi-species camera-trap studies use a mix of survey-design strategies and include these design features during statistical analysis.
The recent increase in wind energy facilities (WEF) has led to concerns about their effect on wildlife. While the focus of most studies has mainly been on increased mortality of birds and bats due to collision, indirect effects, such as behavioural responses, are currently gaining attention. Indeed, effects of WEF on the behaviour of forest dwelling wildlife still remain largely unknown. Using GPS-tracking of 16 individuals, we studied how seasonal resource selection of the capercaillie Tetrao urogallus, a forest grouse species known as sensitive to disturbance by human presence and infrastructure, was related to wind turbines and other environmental covariates in a wind farm in Sweden. During the lekking season, the probability of site-selection by capercaillie decreased with increasing turbine noise, turbine visibility and turbine shadow. During summer, we found reduced resource selection with increasing proximity to the turbines (up to 865 m), turbine density, noise, shadow and visibility. Furthermore, we found an avoidance of turbine access roads. Due to the high collinearity of the wind turbine predictors it was not possible to identify the specific mechanism causing turbine avoidance. Our study reveals that forest dwelling species with known sensitivity to other forms of human disturbance (i.e. recreation) are also likely to be affected by wind turbine presence. In addition, we provide proximity thresholds below which effects are likely to be present as a basis for conservation planning.
Liselotte Wesley Andersen, Henriette Sallo Schousgaard, Johnny Kahlert, Anton Linnet, Ole Hyttel Jensen, Erik Arnfred Thomsen, Flemming Sørensen, Hans Jørgen Baagøe, John Frikke, Henrik Jacobsen, Bo Håkansson, Volker Loeschcke, Aksel Bo Madsen
In the past the European otter Lutra lutra was distributed throughout most of Europe but since the 1980s its distributional range has been reduced. Currently, the otter population is increasing. Conservation efforts have been implemented, however due to the natural elusiveness of the species it is difficult to monitor. Non-invasive sampling has proven to be the most effective method to derive population parameters such as presence/absence, genetic variability and population structure in European otters. The method to collect non-invasive samples is robust and provides reliable data. This study investigates the validity of the present state-of-the-art method of identifying otter feces, and suggests modifications and improvements of the method. Results from the comparison of field collected data and data derived from a blind test show that the method is applicable in areas abundant with otters, however the method loses its power in the periphery of the distributional range. In these areas, it would be relevant to supplement traditional sampling with DNA analysis to verify the identification of the sample.
KEYWORDS: aerial survey, Arkansas, dabbling ducks, habitat use, Mississippi Alluvial Valley, spatial random effect, species distribution modeling, waterfowl
Mallard Anas platyrhynchos ecology drives current habitat management strategies for most waterfowl; however, are these management strategies suitable for other dabbling duck species? Migratory waterfowl, in addition to mallards, in the lower Mississippi Alluvial Valley experience heavy hunting pressure, so management strategies should be appropriate for a broader array of species. We investigated habitat associations of dabbling ducks (dabblers) in the Arkansas portion of the Mississippi Alluvial Valley and factors driving winter distributions. We modeled winter aerial survey data over seven years with Bayesian spatio–temporal models to test what landscape covariates most affected dabbler habitat use. We found that dabbler distributions were closely associated with open water, habitat inundated with surface water and agricultural habitat such as rice, soybeans and fallow fields. Surface water extent and rice field extent were the key drivers of high dabbler abundances. These habitat–covariate associations were the same as used by mallards, suggesting landscape management focused on mallards likely is appropriate for dabblers, at least at the broad scale of our study.
Farmland habitats host important populations of several threatened bird species. So far, how to reconcile farmland management with the maintenance of viable populations of these taxa is a major challenge for conservation biology. Southeastern Italy hosts ca 7000 pairs of breeding lesser kestrels Falco naumanni, representing one of the European strongholds of this small colonial raptor of conservation concern. We firstly assessed the relative importance of managed crops versus semi-natural grasslands in determining the local abundance of lesser kestrels at the landscape scale, and we successively studied the foraging habitat preferences at a smaller spatial scale. Surveys of foraging birds were associated with land-use collection at 191 homogeneous habitat sampling parcels from 14 plots of 16 km2 each, uniformly distributed over a 2400 km2 area. Each plot was visited six times during the 2017 breeding season (May–July). Land-use markedly changed along the season, unripe cereals being dominant in May, while harvested cereal crops prevailed in July. Land-use did not affect lesser kestrel distribution early in the season while foraging birds were more abundant in plots with a greater proportion of harvested cereal crops and a lower one of semi-natural grassland in the late breeding season. In accordance, the analysis of foraging habitat preferences within plots showed that in May unripe cereal crops and semi-natural grasslands were used proportionally to their availability. In June and July, harvested cereal crops were used more than expected from their availability, while semi-natural grasslands were significantly avoided. Our landscape-scale analysis thus indicates that semi-natural grasslands are much less used in comparison to harvested crops during the mid and late parts of the breeding season, suggesting that lesser kestrel may be able to take advantage of crop management practices more than other farmland birds of conservation priority.
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