Search

As global large carnivore populations continue to decline due to human actions, maintaining viable populations beyond protected area (PA) borders is critical. African lions (Panthera leo) ranging beyond PA borders regularly prey on domestic livestock causing humans to retaliate or even preemptively kill lions to minimize impacts of lost livestock. To understand how lions navigate high-conflict areas in human-dominated landscapes, lions were observed and monitored in the eastern Panhandle of the Okavango Delta between October 2014 and December 2016, and five lions were fitted with GPS satellite collars from August 2015 to December 2016. Lion prides and coalitions were small, with all prides having four or fewer females and all coalitions having two or fewer males. Home range size varied between the sexes but was not statistically different (males: x¯= 584 km2, n= 3; females: x¯= 319 km2, n= 2). There was considerable spatial overlap in home ranges as nonassociating, neighboring collared individuals utilized high levels of shared space (female–female overlap = 152 km2, representing 41–56% of respective home ranges; male–male overlap = 125–132 km2, representing 16–31% of respective home ranges). However, neighboring lions varied use of shared space temporally as evidenced by low coefficients of association (< 0.08), avoiding potentially costly interactions with neighboring individuals. Highest levels of overlap occurred during the wet and early dry seasons when flood waters minimized the amount of available land area. All collared individuals minimized time in close proximity (< 3 km) to human habitation, but some individuals were able to rely heavily on areas where unmonitored livestock grazed. While most lions exist within PAs, anthropogenic impacts beyond PA boundaries can impact critical populations within PAs. Studying systems beyond park boundaries with high levels of human–lion conflict while also establishing conservation programs that account for both ecological and sociocultural dimensions will better aid lion conservation efforts moving forward.African Lion (Panthera leo) movements and home range overlap in the human-dominated eastern Panhandle of the Okavango Delta, Botswana.

Depredation of domestic horses (Equus caballus) by jaguars (Panthera onca) is an example of human–wildlife conflict that has not received much attention. We monitored spatio‐temporal activity and distribution of horses in a 2.64‐km2fenced area in the dry forest of northwestern Costa Rica in response to 16 jaguar killings of horses during January‐November 2017. We monitored 4 horses (2 males, 2 females) equipped with global positioning system transmitters from February‐September 2018 to identify daily and seasonal patterns of use of cover types and a water source by horses. We then compared these results to the previous locations where jaguars killed horses to identify the circumstances under which horses seemed more vulnerable to jaguar predation. Based on 1,693 locations, horses spent most time in grassland (92%) rather than forest and edge vegetation (8%) and used a core area of 0.74 km2(kernel density estimation) to 0.86 km2(minimum convex polygon). Of 16 horse predation events by jaguars, 9 events (56%) occurred in grasslands, 4 in forested areas (25%), and 3 in the forest edge (19%), indicating predation events occurred disproportionately from expected counts based on horse use of vegetation. The predation sites were characterized by a higher proportion of edge and a lower proportion of forest compared to a random points. We suggest that when horses explored areas near the edge of forested areas, the chances of being preyed on by jaguars increased. Monitoring the spatio‐temporal activity of horses equipped with GPS transmitters revealed their preference for grasslands (92%) over forested areas. Predation events by jaguars occurred near forest edges (<29 m, compared with a random point distribution), suggesting increased vulnerability in these areas.

Data availability remains a principal factor limiting the use of species distribution models (SDMs) as tools for wildlife conservation and management of rare species. Although data collected in systematic and rigorous fashion are preferable, available data for most species of conservation interest are usually low in both quality and number. Here we show that combining records published in peer-reviewed journals and gray literature sources (e.g., theses, government, and NGO reports) with unpublished records obtained by personal communications from relevant stakeholders affect the predicted distribution of spectacled bears (Tremarctos ornatus) in Peru. We built SDMs using generalized linear models, random forest, and Maxent, first using a dataset that only included published records, and second with a dataset using both published and unpublished records. All models were replicated ten times with random subsets with controlled sample size. Models that combined published and unpublished spectacled bear records had a better performance, irrespective of with SDM method used, increasing the connectivity of the species’ range, and increasing the overall predicted distribution area than models that only included published records. This was because unpublished records added key new localities, reducing spatial sampling biases. Our study shows that the inclusion of commonly disregarded data such as opportunistic records, reports from natural park rangers, student theses, and data-deficient small studies can make an important contribution to the overall ecological knowledge of rare and difficult-to-study species such as the spectacled bear.

Understanding the mechanisms by which similar species coexist in sympatry is a major driver of ecological research. Niche partitioning and ecological plasticity can facilitate spatial and habitat use overlap between generalist and specialist species. Mouse lemurs (Microcebusspp.) are a highly speciose group of small primates that are endemic to the forests of Madagascar. In northwestern Madagascar, the relatively widespread M. murinusoccurs sympatrically with the microendemic M. ravelobensis. We investigated spatial distributions and densities of these two species across a mangrove–dry forest habitat gradient in Mariarano commune. We used capture-mark-recapture techniques and nocturnal line transect surveys along six transects during June and July 2017. Spatial capture-recapture and distance sampling models were used to estimate lemur densities across habitat types. The congeners displayed differential patterns of spatial distribution and densities. Microcebus murinuswas found in similar densities across all habitat types, while M. ravelobensiswas found at much higher densities in dry forests compared with mangroves. This suggests that the generalist M. murinususes a wider array of habitats more evenly than the specialist M. ravelobensis. Our study provides empirical evidence of how cryptic lemur species differ in their habitat use and distribution across an environmental gradient and provides new insights into their ecology in an understudied habitat. Lemurs are one of the most threatened groups of mammals in the world, and understanding how these species are distributed across different forest types is crucial for planning and implementing conservation measures to protect lemur habitat.

The reproductive season of white-tailed deer (Odocoileus virginianus) has been hypothesized to be aseasonal south of about 14°–18°N latitude, where annual variation in day length is low. We tested this idea by using camera-trap data (1,336 photographed individuals identified by age and sex) collected during 2011–2017 in the dry tropical forest of Santa Rosa National Park, northwest Costa Rica, where wet and dry seasons are well-defined. We identified variation in monthly occurrence of spotted deer fawns, as well as the status of antler growth of male deer, specifically related to the very seasonal environment of the region. Year-round reproduction likely occurs, but the rainfall pattern in the area greatly influences the relative frequency of reproductive indicators, with most births occurring during the dry season, and a second peak occurring toward the latter part of the wet season. We speculate that food resources are the major influence on reproductive patterns, and that variation in types and timing of food resource availability likely account for the variation in reproductive patterns.

An understanding of a species’ diet is required to make sound conservation and management decisions. Traditionally, morphological analyses of undigested hard parts from food items remaining in scats have been used to assess diets. More recently, molecular analyses of scats have been used to identify plant and prey species’ DNA, but no studies have compared morphological and molecular diet analyses for large, terrestrial carnivores. We used molecular tools to determine the percentage of black bear and coyote scats that contained 3 common prey species (caribou, moose, and snowshoe hares) in Newfoundland and compared the results to a traditional morphological analysis. We found that a ranking of relative prey frequencies was consistent between the 2 methods, but molecular methods tended to detect prey species in a greater percentage of scats for all prey species. However, there were individual scats in which a prey species was detected by morphological methods only, and we provide evidence that molecular methods could result in false negatives if prey DNA is not uniformly distributed throughout a scat or as a result of PCR inconsistency. We also found that the per sample cost comparison between morphological and molecular analyses was dependent upon whether or not a molecular test was needed to identify scats to the predator species, the cost of developing molecular methods, and the number of samples being processed. We recommend that controlled feeding studies be performed to validate molecular methods and investigate the utility of molecular techniques to estimate the proportions of food items consumed.

Understanding spatiotemporal variability in prey accessibility is important for disentangling predator-prey interactions and is relevant to management interventions to reduce predation. Recently, caribou (Rangifer tarandus) in Newfoundland declined by 66%, with calf predation by black bears (Ursus americanus) implicated as a major proximate mechanism of the decline. Most predation occurs when calves are aggregated on calving grounds. We used telemetry data from 271 caribou and 45 black bears in 2 caribou herd ranges to examine spatial variability in calf accessibility, identify the distribution of potentially predatory bears, and assess the aggregative response of bears to the calf resource. We predicted whether a bear was a visitor to a calving ground during the calving season (a potentially predatory bear) based upon its sex, the herd range it occupied, its distance to the calving grounds, and the season. The distribution of potentially predatory bears and their degree of segregation from non-predatory bears varied seasonally. The probability of a bear visiting the calving grounds during calving decreased with increasing distance from the calving grounds, and was greater for males than for females in all seasons at distances beyond 2.4?km from the calving grounds. Residency time of bears increased in the calving grounds of 1 herd during calving, suggesting an aggregative response to neonates in that area. For both herds, the estimated distribution of potentially predatory bears was much larger than the calving grounds, illustrating that the relevant scale of predator-prey interactions may extend far beyond the area where lethal encounters occur. Our work highlights the value of examining spatiotemporal dynamics of predator movements prior to implementing ecosystem manipulations designed to reduce predation and provides a modeling framework that can be used to guide management interventions in systems with aggregated prey. © 2015 The Wildlife Society.

The use of day beds for extended periods during the transition into and out of the physiological state of hibernation has been documented in many bear populations, but has never been quantifi ed. Additionally, den abandonment by black bears Ursus americanushas rarely been observed at northern latitudes except after den visits by researchers. In three areas on the northern island of Newfoundland, where male and female black bears spent an average of 158 and 178 d denning, respectively, we identified den sites and extended-use day beds (occupied continuously for 6–26 d) remotely using GPS collars, and here provide the first systematic description of the use of these day beds by bears. We documented den abandonment in 6 (9%; 3 F, 3 M) of 67 bear-winters (6 [14%] of 44 radio-collared bears) and the use of extended-use transitional day beds in 16 (24%) of 67 bear-winters (15 [34%] of 44 radio-collared bears, 8 F, 7 M). In 5 of 10 instances bears left their fall day beds on days with > 15 mm of rain (mean = 28.2 mm, range = 15.6–63.6 mm), which was more than would be expected by chance (p < 0.01). We had more than one year of denning data for 17 bears, 6 (35%) of which reused den sites in diff erent years. Further, we observed some bears using day bed and den sites interchangeably. Though we hypothesized that environmental (flooding) or anthropogenic disturbance (researcher-, forestry-related, or recreational) may have played a role in den abandonment, we found no such relationships, nor was there a difference in the rate of abandonment or day bed use between male and female bears. We could not assess the eff ects of microhabitat attributes, condition, or reproductive status, but acknowledge that these factors may have played a role in den changes.

Mongolian gazelles are Central Asia's most abundant plains ungulate and an iconic symbol of large unfragmented grasslands. Despite a long history of commercial harvesting and subsistence hunting by herding households, adult gazelle demographic data is almost non-existent. We calculated cause-specific mortality rates for 49 adult gazelles collared with a global positioning system. Exponential models provided better fits to survival distributions from collared gazelles than did either Weibull or Gompertz models, and yielded an overall estimated annual mortality risk of 36%. The estimated daily hazard rate from human-caused mortality was 30% greater than the hazard rate due to natural mortality alone. Estimated median lifespan of adult gazelles was just 4 years, which concurred with age data taken from incisor cementum annuli obtained from harvested animals and from a natural mass mortality. For gazelles that have already reached adulthood, in the absence of hunting mortality, the estimated median lifespan of collared gazelles increased from 4 years to 8 years. Survivorship estimates from the complete telemetry dataset (including both natural and human-caused mortality sources) yielded lifespan estimates in line with greatly shortened lifespans evident during periods of heightened mortality, whether from a mass-mortality event or commercial hunting. When compared to earlier population models for the species, our results suggest current survival rates based on measures of natural and human-caused mortality will not support a stable population. © 2013 The Wildlife Society.

Conservation concern for fishers (Pekania[Martes] pennanti) in the Pacific states has highlighted a need to develop cost-effective methods of monitoring reproduction in extant and reintroduced fisher populations. We evaluated the efficacy of nipple size as a predictive index of weaning success for females with known reproductive histories from 3 study areas in California. We captured and radiocollared 91 female fishers on 146 occasions between 2004 and 2011 and measured the width and height of all 4 nipples and quantified reproductive status via radiotelemetry. We classified each radiomarked female into 1 of 3 reproductive classes (nonbreeders, attempted breeders, and current breeders) based on our telemetry observations during the den season prior to capture. We used a modified random forests (RF) procedure to account for repeated measures of individual females sampled in multiple years. Our modified RF procedure correctly classified reproductive class for 130 (89%) and 131 (90%) of our 146 observations using raw and weighted vote totals, respectively. We calculated Cohen's kappa of 0.80 and 0.81 using raw and weighted vote totals, respectively, indicating strong model performance. We conclude that nipple sizes of female fishers measured during a livetrapping effort can be used as a cost-effective index of the weaning rates of adult female fishers.

Many demographic parameters of imperiled fishers (Martes pennanti) in the Pacific Northwest remain poorly understood but are necessary to develop conservation strategies; herein we report on fisher reproduction, recruitment, and dispersal on the Hoopa Valley Indian Reservation, California, to help fill key knowledge gaps. Forty radiocollared, breeding-age females exhibited denning behavior on 80 (87%) of 92 opportunities between 2005 and 2011. Twenty-eight female fishers weaned offspring in 55 (65%) of 85 adequately monitored denning opportunities. Two-year-old female fishers were less likely than older females to den and wean kits. We counted 52, and extracted and marked 51, kits comprising 28 litters of 19 females between 2005 and 2008. Average litter size was 1.9 kits (27 females, 24 males, and 1 unknown) 4–12 weeks postbirth. Mean distances between natal dens and centroids of newly established ranges for 7 juvenile females was 4.0 km (range = 0.8–18.0 km); this distance for 1 male was 1.3 km. The recruitment rate of juveniles that successfully established a home range per adult female was 0.19 (0.16 for females and 0.02 for males). Our results suggest that managers should work toward increasing female survival rates and consider translocations to increase and expand existing fisher populations.

Factors affecting juvenile survival are poorly known in the world's most northern antelope, the endangered saiga (Saiga tatarica), yet these factors are fundamental for understanding what drives population change. We monitored Mongolia saiga (S. tatarica mongolica) calves in Sharga Nature Reserve, western Mongolia, during 2008–2010. Our results showed that male and single calves were heavier than females and twins, respectively. However, we identified no significant differences in seasonal or annual survival rates between sexes or between singletons and twins. Litter size and birth mass varied among years, and there was a negative relationship between these variables. Survival of calves during the 1st year was best explained by the covariates of year and litter size (confounded with body mass), suggesting that interannual variation in environmental conditions influenced twinning rates and body mass, and might play a key role in 1st-year survival. We identified 3 sources of mortality—predation by raptors, foxes (red fox [Vulpes vulpes] and corsac fox [V. corsac]), and lynx (Lynx lynx). Most predation was attributed to raptors, such as golden eagles (Aquila chrysaetos) and cinereous vultures (Aegypius monachus). Our results point to both environmental and biotic factors affecting survival of juvenile saiga.

A severe decline of island foxes (Urocyon littoralis) on the northern Channel Islands in the 1990s prompted the National Park Service to begin a captive breeding program to increase their numbers. Using detailed records of all the fox pairs (N?=?267) that were part of the program on San Miguel, Santa Rosa, and Santa Cruz Islands from its inception in 2000 through 2007, we identified factors influencing the breeding success of pairs in captivity in the interest of formulating strategies that could increase captive productivity. We compiled a database of variables including litter size, reproductive success, distance to nearest occupied pen during the breeding season, subspecies, exposure, female age, male age, age difference, female and male origin (wild vs. captive born), same versus different origin, years paired, previous reproductive success by the pair, previous reproductive success by the female, mate aggression-related injuries, male previous involvement in a pair with mate aggression, and female previous involvement in a pair with mate aggression. We used multiple linear regression to identify factors predictive of litter size, and logistic regression to predict the probability of reproductive success. A larger inter-pen distance, older male age, less exposure, and a smaller intra-pair age difference positively affected litter size. The probabilities of reproductive success increased with fewer years paired and less exposure. Comparatively, pairs with wild born females (vs. captive born females), and previously successful pairs (vs. previously unsuccessful and new pairs) were most likely to be successful. These results indicate that the optimal situation was to pair wild-caught females with older males in sheltered pens that were as far from other pens as possible, to maintain successful pairs and repair unsuccessful ones. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

We monitored 142 radiocollared adult (≥1.0 yr old) white‐tailed deer (Odocoileus virginianus) in 3 study areas of Massachusetts, USA, to estimate annual survival and mortality due to legal hunting. We then applied these rates to deer harvest information to estimate deer population trends over time, and compared these to trends derived solely from harvest data estimates. Estimated adult female survival rates were similar (0.82–0.86), and uniformly high, across 3 management zones in Massachusetts that differed in landscape composition, human density, and harvest regulations. Legal hunting accounted for 16–29% of all adult female mortality. Estimated adult male survival rates varied from 0.55 to 0.79, and legal hunting accounted for 40–75% of all mortality. Use of composite hunting mortality rates produced realistic estimates for adult deer populations in 2 zones, but not for the third, where estimation was hindered by regulatory restrictions on antlerless deer harvest. In addition, the population estimates we calculated were generally higher than those derived from population reconstruction, likely due to relatively low harvest pressure. Legal harvest may not be the dominant form of deer mortality in developed landscapes; thus, estimates of populations or trends that rely solely on harvest data will likely be underestimates. © 2011 The Wildlife Society.

We used a mark–resight design to calculate density estimates of fisher (Martes pennanti), a candidate for listing under the United States Endangered Species Act, on the Hoopa Valley Indian Reservation in northwestern California, USA in order to determine population status in 1998 and 2005. Our density estimation results and simultaneous population‐monitoring data provided a post hoc opportunity to evaluate the relative efficacy of 3 classical indexing techniques (catch‐per‐unit‐effort, frequency of detection at camera stations, and frequency of detection at track‐plate stations) and small‐scale occupancy estimation to accurately detect population change. We calculated densities (and 95% CI) of 52 (43–64) and 14 (13–16) fishers/100 km2in 1998 and 2005, respectively. We detected a decline in the relative abundance of fishers between 1998 and 2005 using catch‐per‐unit‐effort indices (χ2≥ 10.18, P≤ 0.007), but not in magnitude similar to our density estimates. We detected an increase (χ2= 4.23, P= 0.040) and no difference (χ2= 1.38, P= 0.240) in the relative abundance of fishers between surveys using frequency of detection indices at camera stations and at track‐plate stations, respectively. Occupancy estimates did not differ between 1998 and 2005. We speculate changes in prey habitat, increases in predation, disease, or some combination of these potential causes, were responsible for the population decline. Our results reinforce the importance of careful thought given to the study goals and potential limitations of any technique. For populations deemed valuable (e.g., at risk or sensitive), we suggest managers consider adopting more defensible, large‐scale occupancy estimation or mark–recapture methods to monitor changes in population sizes. © 2011 The Wildlife Society.

Mongolia’s Eastern Steppe is one of the largest remaining temperate grassland ecosystems and is habitat for Mongolian gazelles (Procapra gutturosa). During four surveys, we quantified vegetation composition, forage quality, and trace elements to gain insights on characteristics of forage that could be influencing how gazelles are distributed across the steppe. Grasses made up between 57% and 68% of all species, Stipaspp. (24–42% of all grasses) being the most abundant. Forbs made up 6% to 23% of all species with Alliumspp. (11–44% of all forbs) the most abundant. The shrubs and dwarf shrubs were least common (7% and 12% of all species) with Artemisia frigidaWilld. (18% and 47% of all shrubs) most common. Spring crude protein values of green vegetation averaged 21.9%. Considered an important forage for gazelles, Stipaspp. was below optimum value in phosphorous (P) and magnesium (Mg). The forbs Alliumspp. and Astragalusspp. and the dwarf shrub Artemisia frigidahad some of the highest crude protein contents and were above optimum for all important elements (except P in Astragalus). Calcium (Ca) and the Ca:P ratio were above optimal at nearly all sites surveyed. Phosphorus levels in vegetation were 96% of minimum requirements for ungulates at maintenance whereas magnesium and calcium were 113% and 145% of minimum requirements for ungulates, respectively. Magnesium and phosphorous were below values considered optimal for lactation and bone development at 78% and 71% of sites, respectively. Gazelles likely satisfy their nutrient requirements by selectively foraging on species that contain high concentrations of critical minerals. During periods of peak demands, particularly calving and postcalving periods, regions with a high abundance of forbs commonly occurring in gazelle diets (Alliumand Astragalus) might be of greater value to lactating females and growing calves and, therefore, sought out.

We hand-captured, fitted with motion-sensitive VHF transmitters, and monitored 19 newborn (1–2 days old) Mongolian gazelle Procapra gutturosaPallas, 1777 calves in Dornod, Mongolia during the 2000 and 2003 calving seasons to identify changes in activity, movements, and sociality with age. Overall, activity was highly variable throughout the day, regardless of age or year. Calf activity increased, however, from day 2 (age = 2 days; 18% total activity) to day 7 (29%), and 3-fold by day 25 (54%). By days 5–8, calves had moved an average of 6.6 km (range: 2–21 km) from capture sites but were still only seen alone or with their mother. By day 24–26, however, they were located an average of 41 km (range: 24–63 km) away from their capture site, and most (7 of 9) were in aggregations of >1000 animals. Mongolian gazelles do not display behaviour associated with “hiders” after about 2–3 weeks. This reflects the wide-ranging, nomadic existence of the species.

The study of interspecific interactions helps scientists and conservationists understand the ability of species to coexist in a given area, improving the conservation and management of ecological communities. Here we present a case study where we tested whether spatial and temporal interactions of white-tailed deer (Odocoileus virginianus),an ungulate native to Costa Rica, and horses (Equus caballus),a domestic ungulate reintroduced to a protected area, might result in avoidance. We used a paired field design with 40 camera traps deployed in two adjacent 228-ha fields within northwestern dry forest of Costa Rica during the wet season. We used general linear models to evaluate the effect of horse presence and vegetation type on white-tailed deer spatial distribution, as well as the Pianka's index to assess evidence of spatial overlapping. In addition, temporal overlap between horses and deer was assessed using the overlap coefficient, and the temporal response of white-tailed deer to horse presence was assessed using a spatially explicit null model approach. Evidence indicated that white-tailed deer used sites with horses more than sites without horses and used grass and shrubland sites more than forested sites. Within the area with horses, spatial overlap between horses and white-tailed deer was intermediate, suggesting insights of a moderate degree of spatial partitioning. Horses and white-tailed deer both showed similar activity patterns with a high degree of overlap, but our null model approach suggested neutral interaction; thus, our results indicated non-negative effects of horse presence on white-tailed deer spatiotemporal activity. Our results are limited by spatial and temporal replication, so caution is recommended when using this information to make decisions in other sites where horses and deer coexist. However, this effort provides relevant and novel information for our study area and can help decision makers to better manage ecological communities in the northwestern dry forest of Costa Rica.

Abstract:The secretive nature of snow leopards (Uncia uncia) makes them difficult to monitor, yet conservation efforts require accurate and precise methods to estimate abundance. We assessed accuracy of Snow Leopard Information Management System (SLIMS) sign surveys by comparing them with 4 methods for estimating snow leopard abundance: predator:prey biomass ratios, capture-recapture density estimation, photo-capture rate, and individual identification through genetic analysis. We recorded snow leopard sign during standardized surveys in the SaryChat Zapovednik, the Jangart hunting reserve, and the Tomur Strictly Protected Area, in the Tien Shan Mountains of Kyrgyzstan and China. During June-December 2005, adjusted sign averaged 46.3 (SaryChat), 94.6 (Jangart), and 150.8 (Tomur) occurrences/km. We used counts of ibex (Capra ibex) and argali (Ovis ammon) to estimate available prey biomass and subsequent potential snow leopard densities of 8.7 (SaryChat), 1.0 (Jangart), and 1.1 (Tomur) snow leopards/100 km2. Photo capture-recapture density estimates were 0.15 (n= 1 identified individual/1 photo), 0.87 (n= 4/13), and 0.74 (n= 5/6) individuals/100 km2in SaryChat, Jangart, and Tomur, respectively. Photo-capture rates (photos/100 trap-nights) were 0.09 (SaryChat), 0.93 (Jangart), and 2.37 (Tomur). Genetic analysis of snow leopard fecal samples provided minimum population sizes of 3 (SaryChat), 5 (Jangart), and 9 (Tomur) snow leopards. These results suggest SLIMS sign surveys may be affected by observer bias and environmental variance. However, when such bias and variation are accounted for, sign surveys indicate relative abundances similar to photo rates and genetic individual identification results. Density or abundance estimates based on capture-recapture or ungulate biomass did not agree with other indices of abundance. Confidence in estimated densities, or even detection of significant changes in abundance of snow leopard, will require more effort and better documentation.

Several potential proximate causes may be implicated in a recent (post‐1984) decline in moose (Alces alces andersoni) numbers at their southern range periphery in northwest Minnesota, USA. These causes include deleterious effects of infectious pathogens, some of which are associated with white‐tailed deer (Odocoileus virginianus), negative effects of climate change, increased food competition with deer or moose, legal or illegal hunting, and increased predation by gray wolves (Canis lupus) and black bears (Ursus americanus). Long‐standing factors that may have contributed to the moose decline include those typically associated with marginal habitat such as nutritional deficiencies. We examined survival and productivity among radiocollared (n= 152) adult female and juvenile moose in northwest Minnesota during 1995–2000, and assessed cause of death and pathology through carcass necropsy of radiocollared and non‐radiocollared animals. Aerial moose surveys suggested that hunting was an unlikely source of the numerical decline because the level of harvest was relatively low (i.e., approx. 15%/2 yr) and the population usually grew in years following a hunt. The majority of moose mortalities (up to 87% of radiocollared moose [n= 76] and up to 65% of non‐radiocollared moose [n= 84]) were proximally related to pathology associated with parasites and infectious disease. Liver fluke (Fascioloides magna) infections apparently constituted the greatest single source of mortality and caused significant pathology in the liver, thoracic and peritoneal cavities, pericardial sac, and lungs. Mortality due to meningeal worm (Parelaphostrongylus tenuis) was less prevalent and was manifested through characteristic neurological disease. Several mortalities apparently were associated with unidentified infectious disease, probably acting in close association with malnutrition. Bone‐marrow fat was lower for moose dying of natural causes than those dying of anthropogenic factors or accidents, implying that acute malnutrition contributed to moose mortality. Blood profiles from live‐captured animals indicated that those dying in the subsequent 18 months were chronically malnourished. Relative to other populations, average annual survival rates for adult females (0.79 [0.74–0.84; 95% CI]) and yearlings (0.64 [0.48–0.86]) were low, whereas those for calves (0.66 [0.53–081]) were high. Pregnancy (48%) and twinning (19%) rates were among the lowest reported for moose, with reproductive senescence among females being apparent as early as 8 years. Pregnancy status was related to indices of acute (i.e., bone‐marrow fat) and chronic (i.e., blood condition indices) malnutrition. Opportunistic carcass recovery indicated that there likely were few prime‐aged males (.5 yr old) in the population. Analysis of protein content in moose browse and fecal samples indicated that food quality was probably adequate to support moose over winter, but the higher fecal protein among animals that died in the subsequent 18 months could be indicative of protein catabolism associated with malnutrition. Trace element analysis from moose livers revealed apparent deficiencies in copper and selenium, but there was limited evidence of direct association between trace element concentrations and moose disease, pathology, or mortality. Time‐series analysis of regional moose counts (1961–2000) indicated that annual population growth rate was related negatively to mean summer temperature, with winter and summer temperatures increasing by an average of 6.8 and 2.1 C, respectively, during the 40‐year period. This change may have increased moose thermoregulatory costs and disrupted their energy balance, and thereby reduced their fitness. Time‐series analysis failed to show a relationship between annual population growth rate and moose or deer abundance, indicating that food limitation via resource competition was unlikely. Population viability analyses, using count data (1961–2000) and demographic data collected during this study, suggested that the northwest Minnesota moose population likely would not persist over the next 50 years. More broadly, we conclude that the southern distribution of moose may become restricted in areas where climate and habitat conditions are marginal, especially where deer are abundant and act as reservoir hosts for parasites. Una recientedisminución (1984) en el númerode alces en los límites sur de su distribución en el noroestede Minnesota pudo haberse debido a diversas causas entre las que se incluye el efecto de patógenos infecciosos algunos de los cuales están asociados con el venado cola blanca (Odocoileus virginianus), los efectos negativos del cambio climático, el aumento en la competencia por comida con venados o alces, cacería legal e ilegal y un aumento en la depredación por lobo (Canis lupus) y oso negro (Ursus americanus). Otros factores de largo plazo que pueden haber contribuido a la disminución de la población de alce incluye a aquellos factores típicamente asociados con un hábitat marginal como deficiencias nutricionales. Evaluamos la supervivencia y productividad entre hembras adultas y alces juveniles con radiocollares (n= 152) en el noroeste de Minnesota entre 1995–2000 y determinamos causas de muerte y patología por medio de necropsias en animales con radiocollar y de animales sin collar cuando fuera oportuno. Recorridos aéreos sugieren que la cacería no fue una causa importante de la disminución debido a que el nivel de animales cosechados fue relativamente bajo (aproximadamente 15% en 2 años) y en general la población creció en años posteriores a la cacería. La mayoría de las muertes de alces (hasta un 87% de alces con radiocollar [n= 76]; y un 65% de alces sin collar [n= 84]) se debió a patologías asociadas a parásitos y enfermedades infecciosas. La infección por el trematodo hepático (Fascioloides magna) aparentemente constituyó la causa de mortalidad más importante y provocó patologías significativas en hígado, cavidades del tórax y peritoneo, saco pericárdico, y pulmones. La mortalidad por verme meníngeo (Parelaphostrongylus tenius) fue menos prevalente y menos manifiesta como enfermedad neurológica característica. Algunas mortalidades aparentemente estuvieron asociadas a enfermedades infecciosas no identificadas, probablemente interactuando con una malnutrición. Los alces que murieron de causas naturales presentaron menos grasa medular que los que murieron por factores antropogénicos o accidentes, lo que sugiere que la malnutrición aguda contribuyo a las muertes. Los perfiles sanguíneos de animales vivos capturados indicaron que aquellos que murieron en los 18 meses subsecuentes estaban crónicamente malnutridos. La tasa de supervivencia promedio anual en hembras adultas y hembras de sobre‐año fue baja (0.79 [0.74–0.84; 95% IC] y 0.64 [0.48–0.86] respectivamente), mientras que entre las crías la tasa de supervivencia fue alta (0.66 [0.53–0.81]) en comparación con otras poblaciones de alces. Los porcentajes de preñes y de crías cuates fueron de las mas bajas reportadas para alce (48 y 19% respectivamente), presentando envejecimiento reproductivo entre hembras de hasta tan solo 8 años. El estado de preñez estuvo relacionado con índices de malnutrición agudos (grasa de medula ósea) y malnutrición crónica (índices sanguíneos de condición corporal). La evaluación de cadáveres encontrados de manera oportunista reveló que lo mas seguro es que existieran muy pocos machos maduros (> 5 años de edad) en la población. El análisis de contenido de proteína en plantas consumidas por el alce y en muestras de heces fecales indicaron que la calidad de la dieta era adecuada para mantener a los alces durante el invierno, pero el elevado contenido de proteína encontrado en muestras fecales de animales capturados que murieron en los siguientes 18 meses pudo ser indicativo de un catabolismo proteico asociado a la malnutrición. El análisis de elementos traza en hígados de alce revelaron una aparente deficiencia en cobre y selenio, pero hubo poca asociación entre las concentraciones de elementos traza y las enfermedades de los alces, su patología o su mortalidad. El análisis de series temporales de los conteos de alces (1961–2000) indicó que la tasa de crecimiento anual estuvo relacionada negativamente con la temperatura promedio en verano, al haberse incrementado las temperaturas promedio en el invierno y verano en alrededor de 6.8 y 2.1 C, respectivamente durante el periodo de 40 años. Estos cambios pudieron haber incrementado los costos termoregulatorios de los alces afectando su balance energético. El análisis de series temporales falló en mostrar una relación entre la tasa de crecimiento estimada de la población de alces y la abundancia de alces y/o de venados, indicando que la población no estuvo limitada por la cantidad de alimento a través de la competencia por el mismo. El análisis de viabilidad de población utilizando los datos de los conteos (1961–2000) así como también datos demográficos colectados en este estudio sugiere que la población de alces del noroeste de Minnesota no persistirá más allá de los próximos 50 años. De manera más general concluimos que la distribución sureña del alce se vera restringida en áreas donde las condiciones de hábitat sean marginales y los venados sean abundantes y actúen como hospederos reserva de parásitos. L'Effet Des Pathogènes, Des Déficiences Nutritionelles Et Du Climat Sur Le Déclin D'Une Population D'Orignaux Plusieurs facteurs pourraient être impliqués dans le récent (depuis 1984) déclin du nombre d'orignaux (Alces alces andersoni) dans une population au sud de leur aire de distribution au nord‐ouest du Minnesota. Ces facteurs pourraient inclure les effets délétères des infections de pathogènes, dont certains sont associés au cerf de virginie (Odocoileus virginianus), les effets négatifs des changements climatiques, l'augmentation dans la compétition pour la nourriture avec les cerfs ou les orignaux; la chasse—légal ou illégal, l'augmentation de la prédation par le loup (Canis lupus) et par l'ours noir (Ursus americanus). Certains facteurs de longue date pourraient avoir contribué au déclin observé chez l'orignal, incluant ceux associés aux habitats précaires et aux déficiences nutritionnelles. La survie et la productivité de femelles et de jeunes orignaux (n= 152) ont été évaluées à l'aide de colliers émetteurs au nord‐ouest du Minnesota durant les année 1995–2000. La cause de la mort et la présence de pathogènes étaient aussi évaluées en effectuant une nécropsie sur la carcasse des animaux équipés d'un collier émetteur et sur d'autres carcasses trouvées par hasard. Les inventaires aériens d'orignaux ne corroboraient pas l'hypothèse que la chasse était la cause du déclin des populations étant donné que le niveau de récolte était relativement bas(i.e. environ 15% tous les deux ans) et que la population augmentait à la suite d'une année de chasse. La majorité des morts observées (jusqu'à 87 % des orignaux avec collier émetteur [n= 76]; jusqu'à 65 % des orignaux sans collier émetteur [n= 84]) étaient liées à des parasites et maladies infectieuses. Les infections causées par la grande douve américaine (Fascioloides magna) semblent entraîner la plus grande proportion des décès et sont aussi une cause importante de maladies du foie, des cavités thoraciques et péritonéales, du sac péricardique et des poumons. Les décès causés par le ver des méninges (Parelaphostrongylus tenuis) étaient moins prévalent et se manifestaient par des maladies neurologiques. Plusieurs morts ont été associées à des maladies infectieuses non identifiées, probablement liées à la malnutrition. La graisse de moelle osseuse était moins présente chez les orignaux morts de cause naturelle que chez ceux morts dans un accident ou d'une cause anthropogénique, corroborant l'hypothèse qu'une malnutrition aiguë contribue à la mortalité des orignaux. Les profils sanguins d'animaux capturés vivants indiquent que ceux morts dans les 18 mois suivant la capture étaient à un niveau de malnutrition chronique. Le taux de survie annuel moyen pour les femelles adultes (0.79 [0.74–0.84; 95% IC]) et les jeunes de l'année (0.64 [0.48–0.86]) était bas, considérant que le taux de survie était élevé pour les veaux (0.66 [0.53–0.81]), par comparaison avec d'autres populations d'orignaux. Le taux de gestation (48%) et de gémellité (19%) était l'un des plus bas rapportés chez l'orignal, et la sénescence reproductive chez les femelles a été observée dès l'âge de 8 ans. La predisposition à la gestation a été liée aux index de malnutrition aiguë (graisse de moelle osseuse) et chronique (indice sanguin). Le peu de carcasses de mâles adultes (>5 ans) retrouvés par hasard indique qu'ils sont très peu nombreux dans la population. L'analyse du contenu protéique des brouts d'orignaux et des échantillons fécaux indique que la qualité de la nourriture disponible était probablement adéquate pour supporter l'hiver, mais le taux plus élevé de protéines fécales retrouvé chez les animaux morts au cours des 18 mois suivants pourrait être indicatif du catabolisme des protéines associé à la malnutrition. L'analyse d'oligoéléments dans le foie révèle des déficiences en cuivre et en sélénium, mais l'association directe entre la concentration des oligoéléments et la santé/mortalité des orignaux était faible. Des analyses chronologiques sur les décomptes régionaux d'orignaux (1961–2000) ont démontré que la croissance annuelle de la population était négativement liée à la température d'été moyenne, avec des températures l'hiver et l'été augmentant respectivement de 6.8 et 2.1 C pour la période de 40 ans. Ce changement pourrait avoir provoqué une augmentation du coût de thermorégulation et une rupture dans la balance énergétique de l'orignal. L'analyse chronologique n'a cependant pas démontré de relation entre le taux de croissance estimé de la population d'orignaux et l'abondance du cerf de virginie ou de l'orignal, révélant que la limitation de la nourriture par la compétition était peu probable. L'analyse de la viabilité de la population d'orignaux du nord‐ouest du Minnesota, utilisant à la fois des données d'inventaire (1961–2000) et des données démographiques amassées au cours de l'étude, suggère que la population devrait s'éteindre au cours de 50 prochaines années. En conclusion, il est fort probable que la portion méridionale de l'aire de distribution de l'orignal soit restreinte dans les habitats limités et où le cerf de virginie est abondant et source réservoir de parasites.

Hybridization presents a unique challenge for conservation biologists and managers. While hybridization is an important evolutionary process, hybridization is also a threat formany native species. The endangered species recovery effort for the red wolf Canis rufus is a classic system for understanding and addressing the challenges of hybridization. From 1987?1993, 63 red wolves were released from captivity in eastern North Carolina, USA, to establish a free-ranging, non-essential experimental population. By 1999, managers recognized hybridization with invasive coyotes Canis latrans was the single greatest threat to successful recovery, and an adaptive management plan was adopted with innovative approaches for managing the threat of hybridization. Here we review the application and results of the adaptive management efforts from 1993 to 2013 by comparing: (1) the numbers of wolves, coyotes, and hybrids captured, (2) the numbers of territorial social groups with presumed breeding capabilities, (3) the number of red wolf and hybrid litters documented each year and (4) the degree of coyote introgression into the wild red wolf gene pool. We documented substantial increases in the number of known red wolves and red wolf social groups from 1987–2004 followed by a plateau and slight decline by 2013.The number of red wolf litters exceeded hybrid litters each year and the proportion of hybrid litters per year averaged 21%. The genetic composition of the wild red wolf population is estimated to include < 4% coyote ancestry from recent introgression since reintroduction. We conclude that the adaptive management plan was effective at reducing the introgression of coyote genes into the red wolf population, but population recovery of red wolves will require continuation of the current management plan, or alternative approaches, for the foreseeable future. More broadly, we discuss the lessons learned from red wolf adaptive management that could assist other endangered species recovery efforts facing the challenge of minimizing hybridization.

The recently diminished caribou (Rangifer tarandus) population in insular Newfoundland, Canada, has been severely limited by predation on newborn calves. These neonates are patchily distributed on the landscape; therefore, to adequately understand predator-prey interactions, the temporal and geographic extent of the distribution of caribou calves must be identified so that current areas with calves can be differentiated from areas without calves. We used telemetry locations of 309 caribou calves and 100 adult females from 4 herds, 2008–2010, to estimate the spatiotemporal distribution of caribou calves during the time when they were most vulnerable to predation, to evaluate the predictability of the calf resource among years, and to assess the degree of aggregation during calving. Patterns of calf distribution were predictable in time and space from year to year, with an average distributional overlap of 68% between years. The dispersion of female caribou during calving varied among herds from highly aggregated (8% and 20% of herd range) to more dispersed (50–70% of herd range). Postcalving (up to 9 weeks) distributions also varied among herds; the 2 more-dispersed herds remained sedentary, whereas both highly aggregated herds migrated away from their calving grounds at the end of June. The most-aggregated herd remained so as it migrated from its calving ground, whereas the less-aggregated herd spread out and moved in a variety of predictable directions. Dispersion and movement patterns varied with forest cover; herds with less forest cover in their range were more aggregated and migratory than herds with more forest cover.

The use of camera‐trap methods, though important, has pitfalls and inconsistencies such as factors and interactions that may influence species photo rates. Jaguar (Panthera onca) camera‐trap studies place cameras at sites where jaguar detections are likely greater (e.g., sites with previous evidence such tracks, feces, and other presence signs), but do not account for potential placement biases. Our study evaluated methodological implications of a paired camera‐trap design at trail and off‐trail locations, and climate seasonality, on photo rates of jaguars, their prey, and competitors. From June 2016 to June 2017, camera traps were deployed at 58 different sites in a hexagon grid array of 3 km2 each in the Sector Santa Rosa (SSR) of Área de Conservación Guancaste in Costa Rica. Half of the cameras were located at a trail location that jaguars were likely to use, and the other half at an off‐trail location closest to each hexagon centroid. We estimated a photographic relative abundance index (RAI; no. of independent photos/100 trap nights) and used Generalized Linear Models (GLMs) to assess statistical evidence of trail location and climate seasonality. With a total effort of 19,408 trap nights, we recorded 12,678 independent photo events of 64 species of amphibians, reptiles, birds, and mammals. For the 3 bird species and 14 mammal species we focused on, most species‐specific RAIs were greater at trail locations (n = 8 species, including jaguars and pumas [Puma concolor]), some were greater at off‐trail locations (n = 2 species, including collared peccaries [Pecari tajacu]), and there was no discernable location effect for others (n = 7 species, including tapirs [Tapirus bairdii] and white‐tailed deer [Odocoileus virginianus]). For jaguars, sex ratio data showed a smaller proportion of males at off‐trail locations. Analysis of competitor and prey interaction data indicated temporal segregation at trail locations. Further jaguar camera‐trap studies should highlight camera placement as important source of bias that might influence results; hence, conservationists must be aware of this to avoid erroneous decisions. [ABSTRACT FROM AUTHOR]

We studied the home-range and core-area size and overlap of Tehuantepec jackrabbits (Lepus flavigularis) by radiotracking 32 individuals between May 2001 and April 2003 in savanna habitat in the Isthmus of Tehuantepec, Oaxaca, Mexico. Annual home-range and core-area sizes averaged 55 ha ± 8 SE and 8 ± 1 ha for 10 adults of both sexes using the 95% and 50% fixed-kernel isopleths, respectively. Seasonal home ranges varied widely for adults, from 15 to 111 ha for females and from 24 to 166 ha for males. Juvenile males had larger seasonal home ranges than did juvenile females (X¯ = 80 and 24 ha). For adult jackrabbits, seasonal home ranges were larger during the 1st year compared to those of the 2nd year of study (X¯ = 87 and 49 ha), particularly for females. Home ranges and core areas of Tehuantepec jackrabbits were comparable in size and overlapped between active periods (nocturnal and crepuscular hours) and inactive periods (diurnal hours). Adults overlapped their home ranges with 1–10 individuals. Home-range overlap among females was greater than among males. Females shared portions of their ranges with other females more frequently than did males with other males. Home-range and overlap analysis suggests that Tehuantepec jackrabbits have polygamous mating behavior and nonterritorial social organization.

We investigated the role of changing abundance of spring foods on female American black bear (Ursus americanus) diet, milk composition, and cub survival in western Massachusetts. We hypothesized that diets would change, percentage milk fat would be higher, and cub survival would be higher in a year when overwintered hard mast was more abundant. We obtained paired samples of milk from 7 adult female bears across consecutive reproductive cycles during which spring diets differed; 1 year followed a bumper acorn (Quereus rubra) crop and estimated spring diets were 25% acorns; the other year followed an extremely poor acorn crop and spring diets were estimated to be 99% skunk cabbage (Symplocarpus foetidus). Postdenning milk was higher in fat (26.7% versus 18.2%; P = 0.0557) during the spring when acorns were abundant, but we did not identify any carryover affect to cub survival. We suggest that adult female black bears compensate for changes in food availability by eating greater volumes of alternative foods, and perhaps allocate resources primarily to milk production; the bears appear to be able to produce milk of adequate quality to sustain cubs, regardless of spring diet.

A pack of 19–29 African wild dogs (Lycaon pictus) in the Masai Mara area of Kenya was monitored during July–August 1989 to document their success in capturing various ungulate species. The pack was most successful killing smaller, abundant ungulate prey, and was not less successful when pack size abruptly was reduced; overall hunting success (all species) was 51%. Abundant prey, low competition with other large carnivores, and large size of pack confound conjecture concerning the evolution of pack size.