Obtaining body condition is an important life history challenge that directly impacts individual fitness and is particularly important for hibernating animals, whose maintenance of adequate body fat and mass is essential for survival. It is well-documented that host-associated microorganisms play a vital role in animal physiology and behavior. Recent work demonstrates that gut microbes are associated with fat accumulation and obesity, particularly the phyla Firmicutes and Bacteroidetes. The focus of most microbiome studies has been on human health or involved lab-reared animals used as a model system. However, these microbes likely are important for individual fitness in wild populations and provide potential mechanistic insights into the adaptability and survival of wildlife. Here we tested whether symbiotic microorganisms within the phyla of Firmicutes and Bacteroidetes were associated with summer mass gain in an exceptionally well-studied wild population of yellow-bellied marmots (Marmota flaviventer) by analyzing 207 fecal samples collected over 5 summer active seasons. Results showed that marmots with higher mass gain rates had a greater relative abundance of Firmicutes. In contrast, a higher relative abundance of Bacteroidetes was associated with lower mass gain rates, but only for marmots living in harsher environments. Similar patterns were found at the family level where Ruminococcaceae, a member of Firmicutes, was associated with higher mass gain rates, and Muribaculaceae, a member of Bacteroidetes, was associated with lower mass gain rates in harsher environments. Although correlative, these results highlight the potential importance of symbiotic gut microbiota to mass gain in the wild—a trait associated with survival and fitness in many taxonomic groups.

Rapid environmental changes—in climate, land use, and biotic interactions—are accelerating species extinctions and extirpations globally. Identifying drivers that threaten populations is essential for conservation yet can be difficult given the variable nature of the response of an organism to biotic and abiotic stressors. We analyzed a long-term monitoring data set to explore demographic responses of fishers (Pekania pennanti) to rapid environmental change in the southern Sierra Nevada, California, United States. Fisher survival was sensitive to both biotic and abiotic factors, although the strength and direction of these effects were ultimately mediated by age and sex. Specifically, male survival was lower among young individuals and decreased with increasing temperatures and fungi consumption. Female survival was resilient to age effects and diet but increased with greater forest heterogeneity and decreased with increasing temperatures and snow depth. Our findings suggest that continued climate change will likely have consequences for fishers through both incremental stressors and extreme weather events, but increasing forest heterogeneity may help to buffer against the impacts of such change. Further, we illustrate the importance of disentangling the effects of intrinsic and extrinsic factors on survival, especially among species with distinct sexual or ontogenetic differences. As global drivers of environmental change intensify in strength and frequency, understanding these complex relationships will allow practitioners to best manage for population persistence and habitat resilience concurrently.

Selection pressures underpinning the evolution of mammalian sociality and body mass variation have spurred great interest for several decades. Because they inhabit a wide range of geographic localities and habitats, African mole-rat subspecies of Cryptomys hottentotus present a unique opportunity to further our understanding of intra- and interspecific variation of sociality and body mass in mammalian species. We compared the demographics and body masses among 4 C. hottentotus subspecies: the Mahali mole-rat, C. h. mahali; highveld mole-rat, C. h. pretoriae; Natal mole-rat, C. h. natalensis; and common mole-rat, C. h. hottentotus within the context of their respective microclimates and evolutionary history. We propose that all ancestral C. hottentotus subspecies were arid-adapted and thus formed large colonies (as found today in the Mahali mole-rat). However, as the subspecies dispersed to occupy habitats of varying aridity and temperature across South Africa, selection for a particular colony size range in each subspecies arose to provide an adaptive fitness benefit to survive in its habitat. Consequently, the Mahali mole-rat—which remained in a warm and arid environment—retained the largest mean colony size, followed by the Natal mole-rat, which—even though inhabiting a hyper-mesic environment—selected for increased colony sizes to offset the energy requirement of thermoregulation (through huddling) in the cooler montane environments they prefer. The common mole-rat and the highveld mole-rat possessed the smallest mean colony sizes, likely the result of inhabiting a mesic and warm environment. At the same time, body mass variation in the C. hottentotus complex is likely linked to colony size variation, with subspecies having the largest colonies possessing the lowest individual body mass.

The biogeographic history of a species results from responses to past and current processes, and understanding those responses at both temporal scales is essential. We explored phylogeographic and current genetic variation structure in Ctenomys flamarioni—a subterranean rodent that inhabits a small region of the coastal plain of Brazil—and contrasted the roles of “present-day niche suitability” versus “historical climate stability” to understand current and past intraspecific genetic diversity. We used both mitochondrial DNA sequences (concatenated Cytb and D-loop, n = 78) and nuclear DNA (9 microsatellites loci, n = 154) molecular markers for individuals across the entire distribution of the species. We used phylogeographic trees, Bayesian clustering, and haplotype networks to explore genetic variation and diversity. We correlated genetic diversity with measures of current niche suitability and potential areas of Late Quaternary paleostability. Phylogeographic patterns confirmed low levels of genetic diversity structured at different hierarchical levels. We also found a weak but significant pattern of isolation by distance, indicating that geographical distance partially modulates genetic differences among populations. We also observed a positive correlation between genetic diversity and climate paleostability for microsatellites at local and regional scales. However, we found no significant association between genetic diversity and niche suitability for microsatellites at local or regional scales. We observed several signatures of bottleneck and population expansion at different geographic scales. Our results suggest that Quaternary climatic fluctuations—acting together with habitat suitability and other contemporary factors—played a fundamental role in elucidating the evolutionary history of the species—including patterns of historical dispersal, and current patterns of habitat occupation and genetic structure. In addition, based on our molecular and environmental data sets from the across the range of the species and considering the restricted endemism of C. flamarioni, we emphasize the urgency of conservation actions to protect this endangered species.

A história biogeográfica de uma espécie é resultado tanto de processos históricos quanto atuais e, compreender ambas as escalas temporais é essencial. Neste trabalho, exploramos os padrões filogeográficos e os padrões atuais de variação genética de Ctenomys flamarioni, um roedor subterrâneo que habita uma pequena região da Planície Costeira do Brasil, e comparamos a adequabilidade climática atual com a estabilidade climática histórica para entender os padrões genéticos atuais dessa espécie. Para isso, utilizamos sequências de mtDNA (um fragmento concatenado de Citocromo b e D-loop, n = 78), e nDNA (nove loci de microssatélites, n = 154) de animais coletados ao longo de toda a distribuição geográfica da espécie, e geramos hipóteses filogenéticas, análises de cluster bayesianos e redes de haplótipos. Ainda, relacionamos a diversidade genética com a adequabilidade climática atual e áreas potenciais de estabilidade climática do Quaternário. Os padrões filogeográficos obtidos indicam que a baixa variabilidade genética observada se encontra estruturada em diferentes níveis hierárquicos. Também foi verificado um fraco mas significativo padrão de isolamento pela distância, indicando que a distância geográfica parcialmente modula as diferenças genéticas entre populações ao longo da distribuição geográfica da espécie. Encontramos uma relação positiva entre a diversidade genética e a paleoestabilidade climática em escalas locais e regionais, assim como sinais de gargalo de garrafa e expansão populacional em diferentes escalas geográficas. Os resultados obtidos, indicam que as flutuações climáticas do Quaternário, agindo em conjunto com a disponibilidade do habitat e outros fatores contemporâneos (como a ocupação e modificação humana do ambiente), têm um papel fundamental na história evolutiva da espécie, bem como para a compreensão dos processos de dispersão, ocupação do hábitat, e padrões atuais de estruturação genética das populações. Finalmente, com base em nossas análises integrativas, e considerando o endemismo de C. flamarioni ao longo de um ambiente costeiro instável e restrito, enfatizamos a necessidade de gerar medidas de proteção urgentes para esta espécie altamente ameaçada.

A Late Holocene (ca. 3,100 to 380 BP) sample of the viscacha rat genus Octomys (Octodontidae) from the Vaquerías Gruta 1 site (VQG1) in western Argentina is reported. Phylogenetic and morphometric comparative analyses with living octodontids support that the VQ-G1 sample is related to the desert specialists Tympanoctomys and Octomys, and is sister to the only living species of the latter, O. mimax. The estimated morphological distance to O. mimax is greater than that between pairs of congeneric octodontid species, and even greater than that between some species belonging to different genera. This suggests that the sample represents a new species, whose young age prevents interpreting it as an anagenetic ancestor of O. mimax. If the new species is the result of cladogenesis, its absence in the current fauna represents actual extinction, which among caviomorphs is added to those of †Clyomys riograndensis, †Dicolpomys fossor, †Ctenomys viarapaensis, and †Galea tixiensis—also extinct in the Late Holocene. Thus, the VQ-G1 sample provides evidence of changes in diversity and distribution undergone by small mammals in southern South America during that time. The potential contribution of the Holocene record may be key to elucidate this issue from both an evolutionary and a conservation perspective. This requires a detailed systematic approach to determine whether the taxa under study are truly independent evolutionary units, as well as geographically broad sampling efforts to distinguish the changes affecting distribution from those producing irreversible changes in diversity.

Se da a conocer una muestra de mandíbulas de la rata vizcacha Octomys (Octodontidae) del Holoceno tardío (ca. 3,100 a 380 años AP) del sitio Vaquerías Gruta 1 (VQ-G1) en la precordillera austral del oeste argentino. Los análisis comparativos, filogenéticos y morfométricos, con octodóntidos vivientes sustentan que la muestra de VQ-G1 está vinculada a los especialistas de desierto Tympanoctomys y Octomys, y es hermana de O. mimax, única especie viviente del género Octomys. La distancia morfológica en relación a O. mimax es mayor que la estimada entre especies congéneres e incluso más amplia que entre algunas especies de distintos géneros de octodóntidos. Esto sugiere que se trata de una especie nueva, cuya corta antigüedad impide que se interprete como ancestro anagenético de O. mimax. Si la especie nueva es producto de cladogénesis, su ausencia en la fauna actual representa una extinción real, la cual entre los caviomorfos se suma a las de Clyomys riograndensis, Dicolpomys fossor, Ctenomys viarapaensis, y Galea tixiensis, extintas también en el Holoceno tardío. De este modo, la muestra de VQ-G1 provee evidencia de los cambios de diversidad y distribución experimentados por pequeños mamíferos en la porción austral de Sudamérica durante el Holoceno. Los fósiles holocénicos podrían contribuir a dilucidar esta cuestión desde un punto de vista evolutivo y de conservación. Esto requiere un enfoque sistemático detallado del registro holocénico para determinar si los taxa en estudio son verdaderamente unidades evolutivas independientes. Serían también necesarios nuevos esfuerzos de muestreo geográficamente amplios para distinguir entre los cambios que afectan la distribución y los cambios que producen modificaciones irreversibles a la diversidad.

Although the European Roe Deer (Capreolus capreolus) is one of the most common and widespread ungulate species in Europe and inhabiting a variety of habitats, few studies have addressed its population structure at a large spatial scale using nuclear genetic data. The aims of our study were to: (i) investigate genetic diversity, level of admixture, and genetic structure across European Roe Deer populations; (ii) identify barriers to gene flow; and (iii) reveal factors that have impacted the observed pattern of population genetic structure. Using 12 microsatellite loci, we analyzed 920 European Roe Deer samples from 16 study sites from northern, southern, central, and eastern Europe. The highest genetic diversity was found in central and eastern sites, and lowest in the northern and southern sites. There were 2 main groups of genetically related populations in the study area—one inhabiting mainly Fennoscandia, and the second in the continental part of Europe. This second population was further divided into 3 to 5 spatially distributed genetic clusters. European Roe Deer belonging to the Siberian mitochondrial DNA clade, inhabiting large parts of eastern Europe, were not identified as a separate population in the analysis of microsatellite loci. No isolation by distance (IBD) was detected between roe deer from the fennoscandian and the continental study sites, but the Baltic Sea was inferred to be the main barrier to gene flow. Only weak IBD was revealed within the continental population. Three lower-level genetic barriers were detected in the western, southern, and eastern parts of the study area. The main factors inferred as shaping the observed genetic diversity and population structure of European Roe Deer were postglacial recolonization, admixture of different populations of the species originating from several Last Glacial Maximum refugial areas, and isolation of several study sites.

Climate change is one of the main threats to biodiversity in the 21st century. However, the effects that it may have on different mammal species are unknown, making it difficult to implement conservation strategies. In this paper, we used species distribution models (SDM) to assess the effect of global climate change on the potential distribution of the 8 of the 9 marsupial species in Mexico, and analyzed their distribution in the current system of natural protected areas (NPAs). We used presence records for each species and bioclimatic variables from the present and the future (2050 and 2080) with 2 contrasting possible scenarios (representative concentration pathways RCP 4.5 and 8.5). We found that Tlacuatzin canescens would have the most stable potential range under any climate change scenario, while the remaining species (Caluromys derbianus, Chironectes minimus, Didelphis marsupialis, D. virginiana, Philander opossum, Marmosa mexicana, and Metachirus nudicaudatus) would undergo notable range losses in the future, though there would not only be losses—according to our SDMs, for all species there would be some range gain under the different climate scenarios, assuming the vegetation cover remained. The current system of NPAs in Mexico currently protects and under the 2 future scenarios would protect less than 20% of the potential range of marsupials, so a reevaluation of their areas beyond the NPAs is highly recommended for the long-term conservation of this group. Our results provide relevant information on the estimated effects of global climate change on marsupials, allowing us to design more effective methodologies for the protection of this portion of the mammalian fauna in Mexico.

El cambio climático es una de las principales amenazas a la biodiversidad en el siglo XXI. Sin embargo, se desconocen los efectos que pueda tener sobre las diferentes especies de mamíferos, dificultando la implementación de estrategias para su conservación. En este estudio, empleamos Modelos de Distribución de Especies (SDM) para evaluar el efecto del cambio climático global sobre la distribución potencial de ocho de las nueve especies de marsupiales registradas en México, analizando además su distribución en el actual sistema de Áreas Naturales Protegidas (ANP). Utilizamos registros de presencia de cada especie y variables bioclimáticas del presente y del futuro (2050 y 2080) con dos escenarios contrastantes (RCP 4.5 y RCP 8.5). Encontramos que Tlacuatzin canescens mostrará el área de distribución potencial más estable ante cualquier escenario de cambio climático. Por el contrario, el resto de las especies (Caluromys derbianus, Chironectes minimus, Didelphis marsupialis, Didelphis virginiana, Philander opossum, Marmosa mexicana y Metachirus nudicaudatus) presentarán notables pérdidas de área de distribución en el futuro. Sin embargo, también encontramos que no sólo habrá pérdidas, ya que de acuerdo con nuestros SDM todas las especies mostrarán cierta ganancia de área de distribución bajo los diferentes escenarios climáticos, en el supuesto de que permanezca la cubierta vegetal. El actual sistema de ANP en México protege y, bajo los dos escenarios futuros, protegerá menos del 20% del área de distribución potencial de los marsupiales, por lo que es altamente recomendable reevaluar sus áreas de extensión para la conservación de este grupo a largo plazo. Nuestros resultados proporcionan información relevante de los efectos probables del cambio climático sobre los marsupiales, lo que permite generar metodologías más efectivas para la protección de los mamíferos en México.

Winter presents environmental and energetic challenges for temperate insectivorous bats as colder temperatures increase metabolic rates while simultaneously reducing resource availability. While bats in northern regions typically hibernate or migrate to circumvent these adverse conditions, there is growing evidence of winter bat activity as weather permits. Bats at lower latitudes may experience shorter, milder winters, increasing opportunities for activity. To better understand the relationship between ambient temperature and winter bat activity, we deployed acoustic detectors in central Louisiana and eastern Texas and examined data at 3 levels of biological organization: overall bat activity, species richness, and species-specific activity. Across 1,576 detector-nights, we recorded 37,435 bat passes. Bats responded positively to warmer temperatures but the temperature threshold for winter activity varied among species, ranging from 7.2 to 15.6 °C. Consequently, observed species richness increased at warmer ambient temperatures. With activity linked to environmental conditions in a species-specific manner, different subsets of the winter bat assemblage may be active from night to night. Additionally, our study adds to a rather limited body of literature of winter bat activity and provides a baseline for future studies as white-nose syndrome and climate change affect North American bat populations.

El invierno ocasiona dificultades ambientales y energéticas a murciélagos insectívoros de zonas templadas puesto que las temperaturas bajas hacen que aumente la tasa metabólica al mismo tiempo que produce la escasez de recursos naturales. Si bien los murciélagos de regiones norteñas típicamente hibernan o migran para eludir estas condiciones adversas, hay evidencias que apuntan a que existen actividades de murciélagos durante el invierno siempre y cuando se cumplan ciertas condiciones ambientales. A menores latitudes los murciélagos cuentan con inviernos más cortos y moderados, lo que favorece al aumento de actividades nocturnas. Para comprender la relación que existe entre la temperatura ambiental y la actividad de los murciélagos durante el invierno, hemos instalado detectores acústicos en el centro del estado de Louisiana y al Este de Texas y hemos examinados los datos en tres niveles de organización biológica: actividad total, riqueza de especies, y actividad específica por especies. De 1.576 noches de muestreo hemos registrado 37.435 pases de murciélagos. Estos, responden positivamente a las temperaturas más cálidas, sin embargo la temperatura umbral para actividades de invierno variaron de 7.2 a 15.6 °C en las distintas especies de murciélagos. Como consecuencia, la riqueza de especies observada aumentó con el aumento de la temperatura ambiental. Debido a que la actividad de murciélagos está relacionada a condiciones ambientales que son específicas para cada especie, distintos grupos de murciélagos del ensamblaje de invierno pueden activarse diariamente. El presente estudio contribuye al limitado número de literatura científica acerca de las actividades de invierno de los murciélagos y sirve de referencia para estudios posteriores como el síndrome de la nariz blanca y los cambios climáticos que afectan a las poblaciones de murciélagos de Norteamérica.

Latrine sites are used as areas for the deposition of scent-containing excretions and play important roles in intraspecific olfactory communication, territoriality, sexual attraction, and defense behaviors of many mammals. African clawless otters (Aonyx capensis) likely use latrine sites as primary areas for scent marking and scent communication but no studies to date have investigated their potential role or site selection. We assessed latrine site selection at 2 spatial scales (micro- and macroscale) and recorded behaviors via camera trap recordings. Thirty-eight latrine sites were identified and assessed at 2 locations in Mtunzini on the north coast of KwaZulu-Natal, South Africa (uMlalazi Nature Reserve and Zini Fish Farm) during the months of August to November 2021. Latrine sites were identified through several intensive surveys, while we characterized nonselected sites through a systematic sampling approach. Latrine and control sites were inventoried along a 52-m buffer around all water bodies in both study areas. At each site we measured a series of potential environmental predictors, including horizontal and vertical vegetation cover, surface slope, and averaged wind speeds for days classified as relatively wind-still and relatively windy. To assess the relative role of various environmental predictors, we used a binomial generalized linear model resource selection function to model both spatial scales of latrine site selection. The majority of latrine sites were located at the ecotone between 2 vegetation units or between a vegetation unit and a water source. At a macroscale, latrine sites were associated with areas containing little vegetative substrate cover and minimal canopy cover. The top-ranked models at the microscale also indicated that latrine sites were characterized as occurring in open areas with less canopy and horizontal cover and on flatter areas that are relatively protected against wind. The most common behaviors recorded at 3 latrine sites were the “jiggle dance” (42%) and sniffing (29%). We hypothesize that otters evaluate numerous environmental parameters to enhance the functionality of latrine sites. For example, sites with little vegetative cover may increase the conspicuousness of latrines to conspecifics, while areas exposed to less wind likely aid in the retention of scent. Ongoing research is characterizing the behaviors of otters around latrines and chemical signatures of latrine sites in an effort to facilitate interpretation of their social function to African clawless otters.

Large mammals in temperate climates typically display seasonal patterns of habitat use. However, these patterns are often overlooked because large mammals are usually surveyed at annual intervals. In addition, most studies focus on a single species and ignore other species with which the focal species could interact. Knowing seasonal patterns of habitat use in multiple species and understanding factors that cause these patterns can provide further detail on population dynamics and guide effective conservation planning. Here, using dynamic occupancy modeling, we analyze 11 years of camera-trap data collected in northwestern Anatolia, Turkey, to investigate seasonal habitat use of 8 large-mammal species: Brown Bear (Ursus arctos), Eurasian Lynx (Lynx lynx), Gray Wolf (Canis lupus), Red Fox (Vulpes vulpes), Wild Boar (Sus scrofa), Roe Deer (Capreolus capreolus), European Hare (Lepus europaeus), and Red Deer (Cervus elaphus). For each species, we study the strength of seasonality in habitat use and its dependence on human population density and elevation, which have been shown to affect distributions of species in the region. Although all species exhibited seasonality in habitat use, the strength of this seasonality varied among species; it was strongest in Wild Boar, Roe Deer, and Brown Bear. Moreover, except for Brown Bear, all species tended to avoid sites close to humans. The species responded differently to changing elevation; increasing elevation had both positive and negative effects on species-specific colonization and desertion probabilities, and these effects were likely related to either feeding habits or tendency to avoid humans. These results indicate that seasonality should be taken into consideration in population studies. However, because species differ, seasonality patterns should be identified separately for each species of interest, as differences in these patterns can explain the underlying dynamics of habitat-use patterns more accurately.

Antlers are a costly trait that require skeletal reserves to grow to a large size. Thus, insight into variation in antler size requires understanding the connection between antler and body size, which can be summarized through ontogenetic and static scaling relationships. Both types of scaling relationships are also needed to examine the influence of factors besides body mass on antler growth at different ages and whether the effects of these factors diminish with age. Dietary and maternal effects might decline with age as individuals attempt to mitigate size deficits. We examined the potential effects of diet and maternal attributes of dam (mother) age at birth and litter size on body–antler mass relationships throughout ontogeny and at discrete ages. Data on age, maternal characteristics, body mass, and antler mass were gathered from captive, pen-raised White-tailed Deer (n = 168) that consumed either a low-energy (1.77 kcal/g) or standard-energy diet (2.65 kcal/g) from the time they were weaned until they perished by 5.5 years of age. Both types of scaling relationships were estimated with linear mixed-effects models to account for repeated measurements of males, dams, and sires. Diet affected ontogenetic scaling relationships. Males eating the low-energy diet had faster antler growth when young and lighter in body mass than when they were older and heavier—whereas males fed the standard-energy diet had a similar rate of antler growth across the range of body masses. A Bayesian Information Criterion model selection analysis indicated that diet and litter size (singleton, multiple births), but not dam age at birth influenced static scaling relationships. Static scalar coefficients up to 3.5 years of age were positively allometric (>1.0), but isometric (1.0) in 4.5- and 5.5-year-old males. Furthermore, diet and litter size influenced both intercepts and slopes in only the youngest males (1.5 years) indicating that dietary and maternal effects can diminish with age. Body–antler mass relationships are complex. Young males that are small because of maternal effects, for example, might still be able to mitigate smaller body and antler sizes at older ages.

Disease ecologists commonly use abiotic factors (e.g. temperature and moisture) or measures of biodiversity (e.g. species richness) to predict Lyme disease transmission patterns, but variance in infection probability among individuals within a population is poorly understood. Most studies assume intraspecific consistency, but recent evidence suggests that individual traits, such as animal personality, may drive differences in encounter rates with infected vectors and pathogen transmission probabilities through differential space use and microhabitat selection, leading to intraspecific variation in infection probability. In addition, because vectors and hosts are nonrandomly distributed across a landscape, land-use changes that modify key habitat features—such as forest management practices—may substantially alter associations between individual traits and infection probability. To address these gaps in our knowledge, we used a large-scale capture–mark–recapture study targeting Peromyscus mice in Maine, United States, to test whether personality drives probability of Borrelia burgdorferi infection in hosts within managed forest compartments with different silvicultural treatments. Specifically, we tested effects of individual phenotypic traits (physical and behavioral) and environmental traits (microhabitat and forest type) on infection probability within 2 species: P. leucopus and P. maniculatus. We found evidence that boldness negatively influences infection probability in P. maniculatus, and that body mass positively influences infection probability in both species. We found no effect of mouse density, microhabitat, or forest type in our analyses. These results suggest that personalities vary in their functional contributions to the natural cycle of B. burgdorferi, and that broader integration of behavioral diversity in disease ecology studies may aid in identifying key transmission zones for this rapidly expanding vector-borne zoonosis.

Disturbance events are increasing at a global scale, with cascading impacts to ecosystems and residents therein that include fragmentation and altered vegetation structure and composition. Such changes may disproportionately impact small mammal movements, risk perception, and community dynamics as smaller species perceive such changes at finer spatial scales. We examined movement response to burn severity, vegetation structure, and composition in Mexican woodrats (Neotoma mexicana), a common but understudied small mammal species. The study was conducted on Mt. Graham in southeastern Arizona, United States, following a fire that burned over 19,400 ha. We measured path tortuosity of woodrats translocated over patches of different burn severity. Tortuosity can indicate microhabitat selection, foraging behavior, and perceived predation risk—features affecting population-level processes that changes in community composition alone cannot fully demonstrate. We captured woodrats, released them 50 m away from their midden, and used fluorescent powder to track woodrat movement paths through areas of low–severe burn severity. We analyzed features of the resulting powder trails including straightness, average step length, fractal dimension, and squared displacement. We also compared used versus expected vegetation structure and composition along movement paths across burn severities. Analyses indicated shorter step length with increased bare ground, as well as higher squared displacement in areas with more logs. Vegetation analyses likewise showed that logs were heavily used in low-burned areas, whereas dense vegetation was avoided in highly burned areas. Burn severity alone did not have a direct effect on movement parameters, rather its influence on vegetative composition and structure appears to be most important. Selection for logs and avoidance of dense vegetation may be attributed to auditory concealment and ease of travel. With projected increases in wildfire extent and severity, this work represents an understudied approach to understanding these disturbances and their effects on ecological communities.

Los eventos de perturbación están aumentando a escala global, con alto impacto para los ecosistemas y sus residentes que incluyen fragmentación y alteración de la estructura y composición de la vegetación. Dichos cambios pueden afectar desproporcionadamente los movimientos de los pequeños mamíferos, la percepción de riesgo y la dinámica comunitaria, ya que las especies más pequeñas perciben dichos cambios en escalas espaciales más finas. Examinamos la respuesta del movimiento de acuerdo a la gravedad de las quemaduras, la estructura de la vegetación y la composición en los woodrat mexicanos (Neotoma mexicana), una especie del pequeño mamífero común poco estudiada. El estudio se llevó a cabo en el monte Graham, en el sureste de Arizona, USA, tras un incendio que quemó más de 19.400 ha. Medimos la tortuosidad del camino de los woodrat traslocados sobre parches de diferente gravedad de quemaduras. La tortuosidad puede indicar selección de microhábitat, comportamiento de búsqueda de alimento y riesgo percibido de depredación, características que afectan los procesos a nivel poblacional y que los cambios en la composición de la comunidad por sí solos no pueden demostrar completamente. Capturamos woodrat mexicanos, los liberamos a 50 m de su muladar y utilizamos polvo fluorescente para rastrear las rutas de movimiento que dejarían a través del área con quemaduras de gravedad baja y severa. Analizamos las características de los rastros de polvo fluorescente que dejaron los woodrat, incluido la rectitud, la longitud promedio del paso, la dimensión fractal y el desplazamiento al cuadrado. También comparamos la estructura y composición de la vegetación utilizada versus la esperada a lo largo de las rutas de movimiento a través de la gravedad de los incendios. Los análisis indicaron una longitud de paso más corto con mayor suelo desnudo, así como un mayor desplazamiento cuadrado en áreas con más troncos. Los análisis de vegetación también mostraron que se utilizaron muchos troncos en áreas poco quemadas, mientras que se eludía la vegetación densa en áreas muy quemadas. La gravedad de las quemaduras por sí sola no tuvo un efecto directo sobre los parámetros de movimiento, sino que su influencia sobre la composición y estructura vegetativa parece ser la más importante. La elección de troncos y el eludir vegetación densa pueden atribuirse a que los woodrat evitan hacer ruido para protegerse de los depredadores, y por la facilidad de viajar. Con los incendios forestales proyectados a aumentar en extensión y gravedad, este trabajo representa un enfoque poco estudiado para comprender las perturbaciones y sus efectos en las comunidades ecológicas.

The San Quintin Kangaroo Rat, a rodent species microendemic to the San Quintin–El Rosario region in Baja California that was considered potentially extinct in the wild, was recently rediscovered. This stimulated subsequent searches by us throughout its known distribution range and on sites that seemed suitable beyond its limits. We captured the species at 19 out of 42 localities surveyed, of which 6 are beyond its historically known distribution range, expanding the latter by ∼60 km. Most sites occupied by the species occur on abandoned farmland in early ecological successional stages. Our data support that in the highly transformed agricultural landscape into which the region was converted in the 20th century, the species was able to survive undetected and colonize/recolonize sites once habitat became adequate after agricultural abandonment. This exhibits that the species is highly resilient and persisted as a metapopulation. Further research and conservation actions must be framed within context of the region's agricultural development.

Quintín–El Rosario, Baja California, considerada potencialmente extinta, se redescubrió recientemente. Ello estimuló búsquedas en todo su rango de distribución conocido y en sitios potenciales que parecían adecuados más allá de sus límites geográficos. Capturamos a la especie en 19 de 42 localidades, de las cuales 6 estaban fuera de su rango de distribución históricamente conocido, expandiendo este rango en ∼60 km. La mayoría de los sitios ocupados por la especie se encuentran en tierras de cultivo abandonadas en etapas tempranas de sucesión ecológica. Nuestros datos respaldan la hipótesis de que el paisaje agrícola altamente antropizado, en el que se convirtió la región en el siglo XX, la especie sobrevivió en refugios y colonizó/recolonizó sitios una vez que el hábitat se volvió adecuado después de su abandono agrícola. Esto mostró que la especie es altamente resiliente y persistió como una metapoblación. Las futuras acciones de investigación y conservación deben enmarcarse en el contexto del desarrollo agrícola de la región.

Urbanization often results in biodiversity loss and homogenization, but this result is not universal and there is substantial variability in the spatiotemporal effects of urbanization on wildlife across cities and taxa. Areas with lower population and housing density are some of the fastest-growing regions in the western United States; thus, more research in these areas could offer additional insight into the effects of urbanization on wildlife and the potential importance of wild spaces in maintaining a diverse biotic community surrounding developed areas. To address this need, we conducted a study to identify the effects of urbanization (i.e. housing density) on mammals along a housing density gradient from wilderness to suburbia in Missoula, Montana. We deployed 178 motion-activated trail cameras at random sites within urban/suburban, exurban, rural, and wild regions from May to October 2019 to 2020. We identified all mammals >150 g, then evaluated how housing density influenced: (i) occupancy and (ii) species richness using multispecies occupancy models; (iii) relative abundance using Poisson models; and (iv) diel activity patterns using kernel density estimation and logistic regression. Urbanization was the strongest driver of mammal distribution, with a linear decline in mammal species richness as housing density increased. Urbanization also had strong effects on occupancy and detection rates, with larger-bodied mammals generally having stronger negative associations. Overall, mammal relative abundance was highest in suburban regions; however, this effect was largely driven by White-tailed Deer. Natural environmental factors explained most changes in mammal nocturnal activity; however, urbanization strongly affected nocturnality in some species, with Black Bear and White-tailed Deer becoming more nocturnal and Red Fox and Northern Raccoon becoming less nocturnal as housing density increased. While our study confirms that some mammals can live and thrive in developed areas, it emphasizes the importance of maintaining wild areas for those species that cannot.

California sea lions (Zalophus californianus) are distributed along the Gulf of California and northeastern Pacific coast. Genetic studies have suggested the existence of 3 to 4 subpopulations in Mexico—1 on the Pacific coast of the Baja California peninsula (PC) and 3 in the Gulf of California—but the extent of this divergence is unclear, and it remains unknown if these subpopulations are morphologically distinct. In this context, we analyzed variation in skull size and shape of adult males between 5 and 13 years of age among 2 (north and central) of the 3 subpopulations of Z. californianus from the Gulf of California and the PC in Mexico. However, since the sample sizes for the 2 subpopulations in the Gulf of California were small, we merged all samples into 1 that we called the Gulf of California (GC) subpopulation. Artificial neural networks and geometric morphometrics were used to analyze skull images to quantify the extent to which these geographically separated subpopulations are undergoing morphological divergence. Our results find no significant differences in size in any view between the 2 subpopulations, but significant differences in the morphology of the dorsal, ventral, and lateral views of the skull between the 2 subpopulations. Overall, Z. californianus from the GC subpopulation have wider and lower skulls, extended back and outward with a more voluminous (bulky) nuchal crest, and narrow rostrum in comparison with skulls of Z. californianus from the PC subpopulation. Results concur with a previous genetic-based study, demonstrating that Z. californianus from both subpopulations in Mexico are diverging in their skull morphology and perhaps suggesting that they are experiencing different evolutionary pressures.

El lobo marino de California, Zalophus californianus se encuentra ampliamente distribuido a lo largo de la costa nororiental del Pacífico y el Golfo de California. Los estudios genéticos han sugerido la existencia de 3 a 5 subpoblaciones en México— una en la costa del Pacífico de la península de Baja California (CP) y tres en el Golfo de California— pero el grado de divergencia no es claro, y se desconoce si estas subpoblaciones son morfológicamente distintas. En este contexto, analizamos la variación del tamaño y la forma del cráneo de machos adultos de entre 5 y 13 años entre 2 (norte y central) de las 3 subpoblaciones de Z. californianus del Golfo de California y la de la CP en México. Sin embargo, dado que los tamaños de muestra de las 2 subpoblaciones del Golfo de California eran pequeños, juntamos todas las muestras en 1 sola a la que llamamos la subpoblación del Golfo de California (GC). Se utilizaron técnicas de morfometría geométrica y redes neuronales artificiales para analizar imágenes de cráneos con el fin de cuantificar en qué medida estas subpoblaciones separadas geográficamente, han divergido morfológicamente. Los resultados no muestran diferencias significativas en ninguna de las vistas entre las 2 subpoblaciones, pero si hubo diferencias significativas en la forma de las vistas dorsal, ventral y lateral de los cráneos entre las dos subpoblaciones. En general, los ejemplares de Z. californianus de la GC tienen cráneos más anchos y bajos, 1 caja craneana alargada anteroposteriormente con 1 cresta sagital más voluminosa (voluptuosa) y un rostro más angosto en comparación con los cráneos de los Z. californianus de la CP. Nuestros resultados son consistentes con trabajos genéticos previos, demostrando que ambas subpoblaciones de Z. californianus en México están divergiendo en la forma de sus cráneos, lo que sugiere que están experimentando presiones evolutivas distintas.

Comparatively little is known about the distribution and ecology of Aardvark (Orycteropus afer) and Temminck's Ground Pangolin (Smutsia temminckii). Both are elusive species that are normally nocturnal, solitary, and fossorial. Formally collected records have been used to map the distribution of these species, and social media records provide a tool to gather information on their distribution and ecology. We obtained 680 photographs and videos of aardvarks and 790 of ground pangolins in southern Africa from publicly available posts on Facebook and Instagram (2010–2019). The images provide new insights into the distribution, activity, drinking, and predation—and confirm that aardvarks are more diurnally active when they are in poor body condition. Social media can provide useful supplementary information for understanding of elusive mammals. These “soft” data can be applied to other species.