Examination of spatial variation in demography among or within populations of the same species is a topic of growing interest in ecology. We examined whether spatial variation in demography of a tropical megaherbivore followed the “temporal paradigm” or the “adult survival paradigm” of ungulate population dynamics formulated from temperate-zone studies. We quantified spatial variation in demographic rates for giraffes (Giraffa camelopardalis) at regional and continental scales. Regionally, we used photographic capture-mark-recapture data from 860 adult females and 449 calves to estimate adult female survival, calf survival, and reproduction at 5 sites in the Tarangire ecosystem of Tanzania. We examined potential mechanisms for spatial variation in regional demographic rates. At the continental scale, we synthesized demographic estimates from published studies across the range of the species. We created matrix population models for all sites at both scales and used prospective and retrospective analyses to determine which vital rate was most important to variation in population growth rate. Spatial variability of demographic parameters at the continental scale was in agreement with the temporal paradigm of low variability in adult survival and more highly variable reproduction and calf survival. In contrast, at the regional scale, adult female survival had higher spatial variation, in agreement with the adult survival paradigm. At both scales, variation in adult female survival made the greatest contribution to variation in local population growth rates. Our work documented contrasting patterns of spatial variation in demographic rates of giraffes at 2 spatial scales, but at both scales, we found the same vital rate was most important. We also found anthropogenic impacts on adult females are the most likely mechanism of regional population trajectories.

Monthly field surveys were conducted between August 2010 and July 2015 to explore seasonal group characteristics and occurrence patterns of Indo-Pacific humpback dolphins (Sousa chinensis) in Xiamen Bay, China. Dolphins formed larger groups in winter and spring (dry seasons) than in summer and autumn (wet seasons; U = 1,564.00, P < 0.001). Sighting encounter rates were higher during the wet season than during the dry season (U = 181.00, P < 0.001), while individual encounter rates were not significantly different between seasons (F = 0.494, d.f = 3, P = 0.688). Dolphin sightings and the foraging events were mainly found in inner harbors (Western Harbour and Tongan Bay) during the dry seasons and in peripheral areas (Jiulong River Estuary, Wuyu, and Dadeng-Xiaodeng) during the wet seasons. Seasonal occurrence patterns may be associated with the seasonal prey shifts between these different environments.

Although montane sky islands surrounded by desert scrub and shrub steppe comprise a large part of the biological diversity of the Basin and Range Province of southwestern North America, comprehensive ecological and population demographic studies for high-elevation small mammals within these areas are rare. Here, we examine the ecology and population parameters of the Palmer's chipmunk (Tamias palmeri) in the Spring Mountains of southern Nevada, and present a predictive GIS-based distribution and probability of occurrence model at both home range and geographic spatial scales. Logistic regression analyses and Akaike Information Criterion model selection found variables of forest type, slope, and distance to water sources as predictive of chipmunk occurrence at the geographic scale. At the home range scale, increasing population density, decreasing overstory canopy cover, and decreasing understory canopy cover contributed to increased survival rates.

Plague is a reemerging, rodent-associated zoonosis caused by the flea-borne bacterium Yersinia pestis. As a vector-borne disease, rates of plague transmission may increase when fleas are abundant. Fleas are highly susceptible to desiccation under hot-dry conditions; we posited that their densities decline during droughts. We evaluated this hypothesis with black-tailed prairie dogs (Cynomys ludovicianus) in New Mexico, June–August 2010–2012. Precipitation was relatively plentiful during 2010 and 2012 but scarce during 2011, the driest spring–summer on record for the northeastern grasslands of New Mexico. Unexpectedly, fleas were 200% more abundant in 2011 than in 2010 and 2012. Prairie dogs were in 27% better condition during 2010 and 2012, and they devoted 287% more time to grooming in 2012 than in 2011. During 2012, prairie dogs provided with supplemental food and water were in 23% better condition and carried 40% fewer fleas. Collectively, these results suggest that during dry years, prairie dogs are limited by food and water, and they exhibit weakened defenses against fleas. Long-term data are needed to evaluate the generality of whether droughts increase flea densities and how changes in flea abundance during sequences of dry and wet years might affect plague cycles in mammalian hosts.

Understanding the diets of carnivores is essential for resolving food web interactions and the population dynamics of both prey and predators and for designing effective strategies for species and ecosystem conservation. As effective predators, wild felids play important roles in various ecosystems, but relatively little is known about the dietary habits of many species, primarily owing to their elusive behavior. We used a DNA-based method to analyze the vertebrates and plants constituting the diet of leopard cats (Prionailurus bengalensis) in the temperate forests of the mountains of southwest China, a global biodiversity hotspot. DNA extracted from leopard cat scats was amplified with primers targeting either the vertebrate mitochondrial 12S rRNA gene (N = 25 scats) or the psbCL region of the chloroplast genome of vascular plants (N = 42 scats). The polymerase chain reaction products were sequenced and prey taxa were assigned based on sequence similarity. We identified a total of 16 taxa of vertebrate prey, with pikas (in 76% of the scats) and rodents (40%) predominating. Plant material belonging to 12 taxa was found in 76% of the samples, and the genus Solanum and subfamily Rosoideae were the most frequently detected plant taxa. The frequency of occurrence of identified plant taxa differed between the spring–summer and fall–winter months. Thus, the leopard cats in our study area have a diversified diet and are highly flexible in adapting their foraging behavior to the locally available prey. Our data suggest that preserving their natural prey base dominated by pikas and rodents may be vital for the subsistence of local populations. The high species resolution and detection sensitivity of the DNA-based method we used in this study make it a powerful and efficient tool for fine-scale analysis of complex diets.

Impacts of large-scale changes in habitat due to human development, invasive species, and climate change are important considerations for wildlife management. Likewise, as efforts increase to recover and restore human-altered landscapes, indirect consequences on nontarget components of the restored ecosystem also must be considered. Currently, efforts are underway to eradicate nonnative Russian olive (Elaeagnus angustifolia) and tamarisk (Tamarix spp.) in Canyon de Chelly National Monument (CACH), United States, yet impacts to native wildlife, including the American black bear (Ursus americanus), which relies on these species for escape cover and foraging habitat, are not fully understood. Further, these efforts have the potential to impact sociopolitical aspects of the ecosystem, namely human–bear interactions (e.g., raiding of crops and livestock). We used occupancy modeling to evaluate black bear foraging ecology and habitat use in CACH to better understand how bears are using native and nonnative habitat resources and how restoration efforts may impact bears and human–bear interactions. We found that black bears rely heavily on Russian olive for food and that habitat use is driven by both native and nonnative (i.e., Russian olive) food resources; thus, restoration of native habitat in CACH may have negative impacts on bears through loss of a primary nonnative food source and escape cover. Furthermore, bear–human interactions may temporarily increase in the short term as bears adjust to this loss. Evaluating habitat use in an occupancy modeling framework provides an effective means for gauging nontarget impacts of restoration efforts on wildlife species, an essential step in effective wildlife management.

Computed tomography (CT) was used to compare the tissue structures involved in sound production and reception in a fetus and its maternal body of a female finless porpoise (Neophocaena asiaorientalis sunameri) found stranded at Huian, Fujian Province, China, in April 2014. Qualitative assessment of the CT images revealed the physical development of main acoustic tissues including melon, blubber, mandibular fat, muscle, and connective tissue in a 10-month old fetus. Compared to the maternal body, the cranium of the fetus was not enclosed, air sacs and nasal meatus were both absent, and the maxilla was much thinner. Furthermore, Hounsfield unit (HU) measurements from CT scanning were used to quantify the difference between the fetus and its maternal body for melon, blubber, mandibular fat, muscle, and connective tissue. Statistical analyses revealed significant differences in HU between all 5 structures melon, blubber, mandibular fat, muscle, and connective tissue (P < 0.001) both in the fetus and maternal body. The median HU values of melon, blubber, mandibular fat, and muscle in the fetus (–61.0, –74.0, –24.0, and 25.0, respectively) were higher than those recorded in the maternal body (–85.0, –85.0, –69.0, and 12.0, respectively). However, the median HU value of connective tissue (50.0) in the fetus was lower than that recorded in the maternal body (60.0). The results show that the acoustic tissue structures were not fully developed in the fetus and depending on the actual age of the fetus the structures may not be fully formed by the time of birth. Further studies are needed to determine at what age finless porpoise calves have fully developed the tissue structures needed to produce and use ultrasound beams for echolocation.

The northern pygmy mouse, Baiomys taylori, occurs throughout the Trans-Mexican Volcanic Belt and southern Altiplano of central Mexico and extends northward in 3 projections into northern Mexico and the United States. We used mitochondrial DNA (from the cytochrome-b and NADH dehydrogenase 2 genes) and morphological data to assess diversity within B. taylori across its geographic range in relation to recognized subspecies and putative physiographic filter-barriers. Our results indicate 5 distinct mitochondrial clades despite little morphological variation across the species' geographic range. The Sierra Madre Oriental and Sierra Madre Occidental separate clades representing the eastern (Gulf coastal lowlands), central (Altiplano), and Pacific coastal lowlands, which appear to be divided into 3 major mitochondrial clades. Based on a preliminary analysis of cranial morphology, we are able to reject the Balcones Escarpment of Texas as an impediment to the well-documented recent northern expansion of the species, while we are unable to reject a causal role of filter-barriers elsewhere in subspecific differentiation. Revision of subspecific taxonomy must await further genetic sampling, particularly along the western and southeastern portions of the species' distribution.

Subterranean rodents are characterized by limited individual mobility and patchy distribution of local populations. Habitat patches where the species is absent may either be unoccupied, but suitable patches, or in fact unsuitable as habitat due to specific habitat features. In the coastal plain of southern Brazil, Ctenomys minutus (Ctenomyidae) inhabits sandy grasslands and dunes. The aim of our study was to analyze the relationship between the distribution of this subterranean rodent and its environment. We considered vegetation and soil features. Our results showed that habitat occupancy patterns of C. minutus are determined by soil moisture and vegetation (food supply), but there might be other habitat features that regulate the habitat choice of this mammal. Habitat discontinuities in the coastal plain of southern Brazil, with numerous barriers to dispersal, are responsible for restricting individuals to their natal areas. This might result in increased intraspecific competition within each population and, consequently, in inbreeding.

A suite of dryland mammals rely on refuges for long-term persistence during alternating cycles of low and high resource availability. Refuges are small, discrete areas into which populations contract during the lengthy dry periods that characterize dryland environments. Little is known about the characteristics of a location that make it functional as a refuge. Similarly, no information exists on how grazing-facilitated landscape modification affects small mammal refuges. To examine these questions, we assessed diet at refuge sites across the low phase (“bust”) of the population cycle of the plains mouse (Pseudomys australis), a threatened, refuge-using rodent coexisting with extensive cattle production in Australia's drylands. The species has a varied diet dominated by species of grasses and forbs (mostly seeds) with a small proportion of invertebrates. Most of the plants consumed are shallow-rooted and short-lived species that should germinate in response to small rainfall events. Coexistence with cattle production is likely to be possible because grazing-tolerant plants are a dominant component of the diet. Our findings provide a plausible explanation for the persistence of P. australis with cattle production in dryland Australia, which should be further investigated to develop management strategies that will enable continued coexistence. This investigation should be extended to consider other refuge-using species of small mammal in pastoral systems.

Oral lesions in wolves (Carnivora: Canidae: Canis lupus) are usually reported in a nonstandardized manner, and often only a few abnormalities are indicated. This approach has likely led to underreporting of oral lesions, thus limiting our ability to interpret wolf health conditions and thus making comparisons across geographical and taxonomic groups difficult. Here, we present a standardized oral exam protocol to examine wolf skulls for their oral lesions. Using this protocol, we analyzed 40 skulls of adult wild Middle East wolves representing 1,680 teeth. Six wolves were Canis lupus arabs, 34 were Canis lupus pallipes. Only 3 skulls showed no oral lesions. We were able to identify a large range of oral lesions and refined subclasses, exceeding the variety of what has been reported on wolf oral lesions so far. No statistical differences were found in the type and number of lesions between the 2 subspecies of wolves. Therefore, the lesions were pooled in subsequent analyses. This standardized protocol should provide a useful framework to assess oral lesions in wolf skulls, facilitating rigorous comparisons across geographic and taxonomic groups.

Contrasting scenarios have been proposed to explain how resource heterogeneity influences group living or sociality. First, sociality may result from individuals in larger groups attaining net fitness benefits by monopolizing access to resources (“resource-defense” hypothesis). Second, sociality may be the fitness-neutral outcome of multiple individuals using a territory with sufficient resources to sustain a group of conspecifics (“resource-dispersion” hypothesis). While previous studies have tended to support the resource-dispersion hypothesis, these analyses have typically examined only 1 or a few predictions, making it difficult to distinguish between the 2 alternatives. We conducted a 4-year field study of Octodon degus to quantify the effects of spatial heterogeneity in food and refuge distributions on group size and 2 components of reproductive success (per capita number of offspring, offspring survival) in this plural breeding and communal rearing rodent. We found only a small effect of heterogeneity of food resources on group size; the effect food resource distribution on group territory size varied across years. Group size did not vary with spatial variation in group territory size and quality. Importantly, there was no covariation between group size and quality of an individual's territory (i.e., a measure of individual access to resources), or between this measure of territory quality and reproductive success, implying no resource-based benefits to social degus. Overall, our results were more consistent with fitness-neutral relationships among spatial heterogeneity of resources, sociality, and territory size. The resource-dispersion hypothesis, however, did not provide a complete explanation for degu socioecology.

A previous study showed that Dromiciops gliroides has deep phylogeographic structure, with 3 allopatric and highly differentiated groups. Here, we constructed on that study by assessing the morphologic variation of D. gliroides. Our results show that along its distribution Dromiciops is morphologically highly variable and that the geographic pattern of morphologic variation matches the phylogeographic pattern. Taken together, morphological and molecular data indicate the existence of 2 unrecognized and unnamed species of monito del monte, which are here named and described. Cranial and dental features can easily distinguish species of Dromiciops. One of the new species is endemic of Chile, and the other new species occurs in Argentina and Chile. D. gliroides s.s. is restricted to the southern part of the genus distribution including Chiloé Island. We comment on the conservation significance of our findings and on the need of continuing with field- and collection-based research in order to characterize the richness of the Chilean mammal assemblage.

Landscape change affects the distribution of wildlife and represents a conservation concern, especially in Asia, which is experiencing rapid development. We examined the impacts of landscape change on corsac foxes in Mongolia. We addressed 2 questions: 1) how do common features of a landscape, such as habitats, topography, and human structures, shape the distribution of the species? and 2) how will the loss of those features affect distribution? We developed an occupancy model based on locations (n = 2,437) collected in Ikh Nart Nature Reserve, then estimated the marginal loss in average occupancy across the landscape when features were removed. The model with the most support indicated that occupancy was best described by the additive combination of open plain, tall grassland, and shrubland habitats. Average occupancy across the reserve was 22% under current conditions. Simulations involving the removal of each habitat resulted in a marginal loss of 12%, 35%, and 49% in average occupancy, respectively. The loss of all 3 habitats, as expected under climate change projections, will probably make the landscape unsuitable. The results provide the first model of corsac fox occupancy, which can be used to examine distribution and impacts of change in other parts of the species' range. They also suggest that managers should plan conservation activities to allow corsac fox distribution to shift northward as the region becomes warmer and drier and vegetation communities change.

Major drainage divides (separating the water flow draining to different seas) may significantly affect the dispersal, distribution, and genetic structure of semiaquatic animals. Assessing this effect is important for the proper management of both endangered and invasive riparian species. Here, I determined the fine-scale impact of the drainage divide between the Baltic Sea and the Black Sea drainage basins on the genetic structure and dispersal of the Eurasian otter (Lutra lutra) in the Bieszczady Mountains (Poland and Slovakia). I investigated the genetic structure of the otter population and assessed 3 alternative dispersal models using 6 landscape genetics methods. The analyses were based on 48 individual genotypes obtained from 622 fecal and gland secretion samples collected in 2008–2011. Results indicate that the major drainage divide is not a barrier to gene flow for this population. This was established by analyses of population genetic structure and confirmed by analysis of the spatial distribution of samples originating from closely related individuals. In line with these findings, the best-supported dispersal model assumed that otters migrate through mountain passes, away from streams, thus revealing that they are able to cross a drainage divide. The genetic structure of the population studied exhibits an isolation-by-distance pattern; however, the locations of several repeatedly recorded or closely related individuals revealed the occurrence of long-distance movements. Confirmation of the high mobility of otters and their ability to cross a major drainage divide ridge suggest that landscape obstacles and discontinuity of river network are unlikely to stop otter dispersal, gene flow, and recolonization of new areas.

A new species of rodent is added to the highly diverse genus Oecomys (Cricetidae, Sigmodontinae, Oryzomyini) based on specimens collected in the Argentinian provinces of Chaco and Formosa. The new species is characterized by a derived carotid circulatory pattern, a feature shared with O. concolor, O. mamorae, and O. sydandersoni. A unique combination of morphological, morphometric, and molecular characters, however, provides unambiguous evidence of its validity as a separate entity. Individuals of the new species are larger than other representatives of Oecomys, and their skulls have wide and cuneate interorbital regions with well-developed supraorbital shelves, long incisive foramina, long palates, absent alisphenoid struts, and broad Eustachian tubes. This new Oecomys appears to be endemic to the Humid Chaco, an ecoregion listed as Vulnerable due to the human impact. Preliminary observations suggest that several specimens from Eastern Paraguay and the Brazilian Pantanal could also be assigned to the new species described herein.

Although many tropical countries have functional wind farms, most of the information on their impact on bat populations has come from temperate zones. Our study is based on a 5-year study (2009–2013) of bat captures using mist nets, acoustic recordings, and carcass searches at a wind farm in tropical southern Mexico. We investigated the composition of bat species, estimated the number of bat fatalities per turbine, and assessed the effect of the spatial attributes of vegetation cover near turbines on numbers of bat carcasses recovered by trophic guild. We recorded 29 bat species at the wind farm. The family Phyllostomidae was best represented in terms of number of species and individuals captured. Glossophaga soricina and G. morenoi exhibited the highest relative abundance, whereas Balantiopteryx plicata had the highest acoustic activity. We found 203 carcasses, including 73 Pteronotus davyi individuals (35.9%); other frequent species were Mormoops megalophylla, Molossus sinaloae, and Lasiurus intermedius. The total number of carcasses found within a year ranged from 17 to 83 (2012 and 2009, respectively), with the corrected estimates ranging from 410 to 1,980, or 4.18–20.20 fatalities/turbine. The number of carcasses recorded was positively correlated with secondary vegetation surrounding turbines but negatively correlated with agricultural fields. The spatial attributes of vegetation surrounding turbines influenced numbers of bat carcasses differentially depending on the bats' trophic guild and habitat use. Contrary to findings from United States and Canadian wind farms, most of the carcasses observed in our study were resident species. Notably, the most commonly captured and acoustically active species were not the most commonly found in carcass searches. To obtain more accurate information about the most vulnerable species and how to reduce the impact on bat mortality, we advise the use of alternative monitoring methods in pre-construction studies.

Rodent communities have multiple functions including comprising a majority of the mammalian diversity within an ecosystem, providing a significant portion of the available biomass consumed by predators, and contributing to ecosystem services. Despite the importance of rodent communities, few investigations have explored the effects of increasing anthropogenic modifications to the landscape on rodents. Throughout the western United States, the construction of artificial water developments to benefit game species is commonplace. While benefits for certain species have been documented, several researchers recently hypothesized that these developments may cause unintentional negative effects to desert-adapted species and communities. To test this idea, we sampled rodents near to and distant from wildlife water developments over 4 consecutive summers. We employed an asymmetrical before-after-control-impact (BACI) design with sampling over 4 summers to determine if water developments influenced total rodent abundance. We performed an additional exploratory analysis to determine if factors other than free water influenced rodent abundance. We found no evidence that water developments impacted rodent abundance. Rodent abundance was primarily driven by vegetation type and year of sampling. Our findings suggested that water developments on our study area do not represent a significant disturbance to rodent abundance and that rodent abundance was influenced by the vegetative community and temporal factors linked to precipitation and primary plant production. Our findings represent one of the 1st efforts to determine the effects of an anthropogenic activity on the rodent community utilizing a manipulation design.

The study of ultrasonic signaling has provided important insights into the ecology of bats and marine mammals, but it is poorly understood in other mammalian taxa. Recently, ultrasonic and high frequency vocalizations were described in southern flying squirrels (Glaucomys volans) in the southeastern United States and Ontario, Canada. Notable differences in many call characteristics suggest regional variation in G. volans communication. We evaluated this observation of regional variation by examining G. volans communication in a little studied portion of their range, the Central Hardwoods Region of the United States. We recorded calls of wild G. volans near West Point, Indiana, with Anabat II ultrasonic recorders. We described frequency and time characteristics of recorded calls, categorized call syllables into types, and used a canonical discriminant function analysis to refine our classification. Our analyses yielded 11 distinct types of G. volans syllables, 7 of which are unlike any calls described in other portions of the species range. This suggests G. volans either communicates in distinct regional dialects or has a much larger call repertoire than previously known. We recommend the creation of locally specific call libraries across the range of G. volans to ensure accuracy in the study of high frequency communication.

Historically, mule deer (Odocoileus hemionus) had a distribution area as large as the Chihuahuan Desert in Mexico, but in recent years, its populations have decreased and distribution areas have become isolated. This species exhibits a high degree of intraspecific variation in its use of habitat resources and home range size. In the Mapimí Biosphere Reserve, where the southernmost population of mule deer is located, over the course of 3 years, 7 females and 1 young male mule deer were monitored using radiotelemetry. Based on the deer location data, home range and habitat use were estimated for each deer. The mean (± SD) home range size for females was 14.70 km² (± 5.89), the home range of the male was 18.05 km². These estimates are among the smallest reported for the species. During the dry season, the use of certain topographic characteristics of the habitat was more similar among the individual deer than it was during the rainy season. The group of deer we sampled did not show preference for any particular type of vegetation, but rather used the majority of plant associations, depending on their availability. Preference was only exhibited by individual deer. The young male made use of the habitat similar to that of most of the females.

Diving mammals use blubber for a variety of structural and physiological functions, including buoyancy, streamlining, thermoregulation, and energy storage. Estimating blubber stores provides proxies for body condition, nutritional status, and health. Blubber stores may vary topographically within individuals, across seasons, and with age, sex, and reproductive status; therefore, a single full-depth blubber biopsy does not provide an accurate measure of blubber depth, and additional biopsies are limited because they result in open wounds. We examined high-resolution ultrasound as a noninvasive method for assessing blubber stores by sampling blubber depth at 11 locations on beluga whales in Alaska. Blubber mass was estimated as a proportion of body mass (40% from the literature) and compared to a function of volume calculated using ultrasound blubber depth measurements in a truncated cone. Blubber volume was converted to total and mass-specific blubber mass estimates based on the density of beluga blubber. There was no significant difference in mean total blubber mass between the 2 estimates (R² = 0.88); however, body mass alone predicted only 68% of the variation in mass-specific blubber stores in juveniles, 7% for adults in the fall, and 33% for adults in the spring. Mass-specific blubber stores calculated from ultrasound measurements were highly variable. Adults had significantly greater blubber stores in the fall (0.48 ± 0.02 kg/kg_MB) than in the spring (0.33 ± 0.02 kg/kg_MB). There was no seasonal effect in juveniles. High-resolution ultrasound is a more powerful, noninvasive method for assessing blubber stores in wild belugas, allowing for precise measurements at multiple locations.

We were able to substantially increase our knowledge of what is likely the least understood endangered terrestrial mammal in the United States, the Florida salt marsh vole (FSMV; Microtus pennsylvanicus dukecampbelli). We developed a predictive landscape model that estimated 264 ha of potential habitat for FSMVs. Evaluating our model, we found voles at 8 of the 36 sites sampled, yielding a model accuracy of 22% for a subspecies that previously was known from only 3 locations. Within areas of potential habitat, FSMVs selected patches of marsh vegetation > 0.49 ha with at least some (≥ 16.75% and ≤ 43.61%) smooth cordgrass (Spartina alterniflora) cover. Suggestive of a meta-population dynamic, FSMV activity decreased outside of patches of smooth cordgrass and saltgrass (Distichlis spicata) identified by the predictive landscape model. Our hierarchical approach to studying FSMVs allowed us to leverage a limited amount of data to ultimately produce important ecological information about an endangered species. This approach easily may be adapted to other mammals with similar information needs.