Understanding the determinants of species rarity is a perennial challenge for ecologists and conservation biologists. In addition to resource specialization, competitive interactions may limit the abundance and distribution of species, thereby accentuating rarity. However, resource partitioning can reduce or altogether offset such competitive effects, and thus permit species to thrive alongside more common, widespread competitors within a narrow range of environmental conditions. In south-central Wyoming, the Wyoming Pocket Gopher (Thomomys clusius) is restricted to areas dominated by Gardner's Saltbush (Atriplex gardneri); it inhabits a geographic range that is entirely encompassed by a relatively abundant and widespread congener (T. talpoides, the Northern Pocket Gopher). However, the consumer–resource dynamics underlying the relationships among Wyoming pocket gophers, northern pocket gophers, and Gardner's Saltbush are poorly understood. We assessed one dimension of consumer–resource interactions—diet selection—between Wyoming pocket gophers, northern pocket gophers, and Gardner's Saltbush, using a combination of path analysis, DNA metabarcoding, and cafeteria-style feeding experiments. We rejected the null hypothesis that Wyoming pocket gophers and Gardner's Saltbush co-occur solely because they require similar soil conditions. Although we could not distinguish between obligate and facultative specialization by Wyoming pocket gophers, the checkerboard-like distributions of these two Thomomys likely reflect the outcome of selection and avoidance of Gardner's Saltbush. We suggest that Wyoming pocket gophers can persist within their small geographic range by capitalizing on Gardner's Saltbush, a halophyte that probably requires some combination of physiological, morphological, and behavioral adaptations to exploit. Low abundances, restricted geographic ranges, or both are hallmarks of rarity, each of which are shaped by diet selection and other consumer–resource interactions. Quantifying consumer–resource interactions can therefore provide a mechanistic basis for the further refinement and testing of hypotheses on the abundance and distribution of closely related species.

Decommissioning the dingo barrier fence has been suggested to reduce destructive dingo control and encourage a free transfer of biota between environments in Australia. Yet the potential impacts that over a century of predator exclusion might have had on the population dynamics and developmental biology of prey populations has not been assessed. We here combine demographic data and both linear and geometric morphometrics to assess differences in populations among 166 red kangaroos (Osphranter rufus)—a primary prey species of the dingo—from two isolated populations on either side of the fence. We also quantified the differences in aboveground vegetation biomass for the last 10 years on either side of the fence. We found that the age structure and growth patterns, but not cranial shape, differed between the two kangaroo populations. In the population living with a higher density of dingoes, there were relatively fewer females and juveniles. These individuals were larger for a given age, despite what seems to be lower vegetation biomass. However, how much of this biomass represented kangaroo forage is uncertain and requires further on-site assessments. We also identified unexpected differences in the ontogenetic trajectories in relative pes length between the sexes for the whole sample, possibly associated with male competition or differential weight-bearing mechanics. We discuss potential mechanisms behind our findings and suggest that the impacts of contrasting predation pressures across the fence, for red kangaroos and other species, merit further investigation.

Mesopredators play an important role in shaping communities, especially when apex predators are no longer present. To persist, mesopredators must confront competition by developing different coexistence strategies. In this study, we used detection and activity data derived from remote cameras to investigate the seasonal coexistence of mesopredators and their interactions with prey in a region of Southwest China where apex predators have been extirpated. We found that Siberian weasels (Mustela sibirica) occupied the entire study area, whereas masked palm civets (Paguma larvata) were restricted to <1,900 m in fall, and expanded their ranges up by about 600 m in spring to likely prey on small mammals. We detected weasels at almost all locations where civets were present, but detection rates and activity patterns for both species suggested avoidance of larger-bodied civets by weasels. We found that weasels were active at all hours and overlapped with all prey both spatially and temporally, whereas civets were nocturnal and crepuscular, which only overlapped with murid rodents. Although we did not directly observe intraguild or predator–prey interactions, evidence suggested that masked palm civets and Siberian weasels seem to coexist due to different seasonal dietary preferences, hunting strategies, and activity patterns.

中小型食肉动物在群落结构的塑造中扮演着重要角色，尤其在顶级食肉动物已经消失的景观中。为了生存，这些物种必须发展出不同的策略，以应对无法回避的种间竞争。在本研究中，我们基于红外相机数据提取物种的探测和活动信息，以期认识中小型食肉动物，尤其是花面狸（Paguma larvata）和黄鼬（Mustela sibirica），还有它们的潜在猎物的关系。我们的研究在中国西南山地的岷山山系之中开展，这里的顶级食肉动物已经消失。结果显示，黄鼬出现在几乎整个研究区域，而花面狸秋天则只记录于海拔1,900 m以下的区域，到了春天就扩展到上至海拔2,500 m的区域，以捕食小型兽类。我们也记录到其他中小型食肉动物的影像，但是其频次相对较低，因而被排除在分析之外。我们发现，记录到花面狸的位点中，几乎都有黄鼬的身影;但是来自位点探测率和活动节律的证据表明，黄鼬会躲避体型更大的花面狸。另外，黄鼬在一天的每个时段都活动，且与各个潜在的猎物类群在时间和空间上重叠;而花面狸则严格地在晨昏和夜间活动，主要与啮齿类猎物重叠。尽管我们没有观察到食肉动物集团内部物种间或者捕食者与被捕食者之间的直接作用，但是，现有证据表明花面狸和黄鼬之所以能够在岷山山系中共处一隅，与二者在不同季节的食性偏好和日活动节律的分化有着莫大的关系。

Divergent activity can change the intensity of species interactions, largely affecting species distributions and abundances, and consequently influencing the composition and function of ecological communities. Few assessments of activity patterns have focused questions around different resource constraints or have examined varying time frames when interaction strengths are expected to increase. We evaluated how activity among carnivores and their prey shifted from early to late winter, coinciding with a presumed decrease in food resources for carnivores, and we measured time between species detections within a camera station. Our study species were three forest carnivores—Pacific martens (Martes caurina), Rocky Mountain red foxes (Vulpes vulpes macroura), coyotes (Canis latrans); and two of their prey—American red squirrels (Tamiasciurus hudsonicus), and snowshoe hares (Lepus americanus). We sampled these species across an extensive network of cameras (n = 107) during the 2014–2017 winter seasons in the Greater Yellowstone Ecosystem, Wyoming. We generated kernel density plots for timing of photographs and calculated the coefficient of overlap among density plots for our predators and prey during early and late winter. Furthermore, we calculated the time-between-detections (i.e., hours) among forest carnivores. We found no consistent trends in time-between-detections across our species pairs. Pacific martens exhibited cathemeral activity that aligned with the peaks in activity of the two prey species. Temporal overlap between coyote and red fox activities was small in early winter, whereas coyotes modified activity in late winter such that they more closely aligned with red foxes. This intraguild convergence of activity may reflect an increase in resource constraints and have consequences for competitive interactions between these two canids. Our study supports the notion that variation in time is an important axis in facilitating coexistence among these forest carnivores and prey species.

Invasive Burmese pythons (Python bivittatus) in the Everglades of Florida, United States, have drastically reduced populations of mammals, yet populations of some rodents appear unaffected by the invasion. To understand this pattern, we radio-tagged cotton rats (Sigmodon hispidus) in areas of high and low python occurrence densities (hereafter occurrence) and quantified the effects of python occurrence, seasonality, and sex on their survival and cause-specific mortality. Cotton rat survival was not influenced by difference in python occurrence (hazard ratio = 1.32, 95% CI = 0.77–2.26, P = 0.30). However, cotton rats were at greater risk from mortalities caused by mammals in areas of low python occurrence. In areas with elevated python occurrence, we attributed most cotton rat mortalities to birds of prey (48.6%) and reptiles (non-python = 24.3%, python = 16.2%). Where python occurrence was relatively low, we attributed cotton rat mortalities to native reptilian (28.6%), avian (35.7%), and mammalian predators (35.7%) with no python-related deaths. In total, pythons were responsible for 11.8% of all cotton rat mortalities. Finding no difference in the survival of cotton rats, despite differences in the causative agents of mortality, suggests that predation pressure from an invasive predator was compensatory for cotton rat population dynamics. This type of compensatory mortality is common for small mammals and helps explain why mammal communities in python-invaded portions of the Greater Everglades Ecosystem are increasingly dominated by cotton rats and other rodents.

Las pitones birmanas (Python bivittatus) invasoras han reducido drásticamente las poblaciones de mamíferos en los Everglades de Florida, United States, pero las poblaciones de algunos roedores parecen no verse afectadas por la invasión. Para comprender este patrón, marcamos con radio ratas algodoneras (Sigmodon hispidus) en áreas de alta y baja densidad de ocurrencia de pitones y cuantificamos los efectos de las densidades de ocurrencia de pitones, la estacionalidad y el sexo en su supervivencia y causa de mortalidad específica. La supervivencia de las ratas algodoneras no estuvo influenciada por la diferencia en las densidades de aparición de pitones (HR = 1.32, IC del 95% = 0.77–2.26, P = 0.30). Sin embargo, las ratas algodoneras corrían un riesgo mayor de mortalidad causada por mamíferos en áreas de baja densidad de ocurrencia de pitones. En áreas con elevadas densidades de ocurrencia de pitones, atribuimos la mayoría de los eventos de mortalidad de ratas algodoneras a aves rapaces (48.6%) y reptiles (no pitón = 24.3%, pitón = 16.2%). Donde las densidades de ocurrencia de pitones fueron relativamente bajas, atribuimos los eventos de mortalidad de ratas algodoneras a reptiles nativos (28.6%), aves (35.7%) y mamíferos depredadores (35.7%) sin muertes relacionadas con pitones. En total, las pitones fueron responsables del 11.8% de todos los eventos de mortalidad de ratas algodoneras. No encontrar diferencias en la supervivencia de las ratas algodoneras, a pesar de las diferencias en los agentes causantes de mortalidad, sugiere que la resiliencia de las ratas algodoneras a un depredador invasivo fue una función de la mortalidad compensatoria. Este tipo de mortalidad compensatoria es común para los pequeños mamíferos y ayuda a explicar por qué las comunidades de mamíferos en las porciones del ecosistema del Gran Everglades invadidas por pitones están cada vez más dominadas por ratas algodoneras y otros roedores.

Closely related species are predicted to have similar fundamental niches, and therefore to compete locally and possibly be constrained to occur allopatrically. Over time, niche differentiation should lead to divergent use of niche axes, such as food or habitat. Most studies of niche divergence or of niche conservatism have focused on multiple species at large spatial scales. We studied two species of closely related chipmunks at two spatial scales in the northern Sierra Nevada. The Long-eared Chipmunk (Tamias quadrimaculatus) and the Shadow Chipmunk (T. senex) are subcryptic species that exhibit extensive geographic overlap in the northern and central Sierra Nevada. Habitat use at the macrohabitat scale was similar, with both species reaching their highest mean abundance in Red Fir (Abies magnifica) forests, but exhibiting divergent secondary affinities. Additionally, macrohabitat associations of T. senex appear to differ from those reported 50 years ago within the same forest, suggesting flexibility in the face of structural habitat changes resulting from forest management actions, climate change, or other factors. At a finer spatial scale, habitat affinities of these chipmunks differed modestly, suggesting that local distribution emphasizes slightly different microhabitat characteristics. We conclude that these species exhibit niche conservatism overall, but whether microhabitat differences reflect competition or niche divergence requires further study. Because T. quadrimaculatus has the smallest geographic range of any Sierra Nevada sciurid, it may be at risk of local extirpation or substantial range restriction in the face of climate change, large-scale high-severity wildfires, and other stochastic threats; the present research sheds light on the ecology of these species, but has important relevance for regional resource managers as well.

Sperm competition results from postcopulatory continuation of male–male competition for paternity. The level of sperm competition is predicted to be highest in species with greater polyandry and weakest in monogamous pairs. Sperm competition levels can be indexed using traits that reflect male investment in fertilization, particularly relative testes mass (RTM). However, the relationship between RTM and levels of sperm competition may also be influenced by precopulatory competition selecting for higher levels of testosterone, also produced by the testes. To test the relationship between RTM and both pre- and postcopulatory male–male competition we compared two bathyergid mole-rat species, the promiscuous Georychus capensis and the monogamous eusocial Fukomys damarensis. The promiscuous species had not only larger RTM, but also a greater proportion of spermatogenic tissue, maximizing germ cell production as well. Conversely, the eusocial species had smaller testes, but a higher proportion of interstitial tissue (which contains the androgenic Leydig cells) and higher levels of testosterone. Consequently, testicular traits as well as testes mass may be under selection, but these are not normally measured. More research is required on relative investment in different testicular traits in relation to both pre- and postcopulatory selection pressures.

Across eastern North America, glacial cycles of the Pleistocene drove episodic latitudinal range shifts by temperate species. Isolation of populations within low-latitude refugia during glacial maxima was enhanced by physiographic barriers, leading to patterns of phylogeographic differentiation that are shared across diverse taxa. Postglacial population expansion created opportunities for differentiated lineages to come into contact, with various potential population-genetic outcomes. Northern short-tailed shrews (Blarina brevicauda) exhibit three mitochondrial phylogroups that probably originated via glacial-age range restriction and isolation. We investigate the history of postglacial expansion and interlineage contact between historically isolated regional populations of B. brevicauda. Morphological differences between skulls of shrews representing a Western lineage and those representing Central and Eastern lineages are consistent with past subspecies delineations. However, we demonstrate broad range overlap between neighboring phylogroups across the Upper Peninsula and Lower Peninsula in Michigan. Further, incongruence between phylogroup association and morphology among individuals in Upper Peninsula populations suggests that genetic admixture between shrews representing the Western and Central groups has occurred in the past and may be ongoing. We show that across most cranial measurements, shrews within the contact zone are morphologically most similar to the Central group regardless of mitochondrial identity, but one measurement in these contact zone shrews (depth of skull) is more similar to that seen in the Western group. These results suggest that hybridization between historically isolated populations has resulted in the origin of a novel skull phenotype that is proportionally deeper, narrower, and shorter than those seen in core Western and Central populations.

Limited sampling for imperiled taxa inhibits effective management by obscuring windows into ecological and evolutionary processes and ultimately thwarting thoughtful conservation efforts. We report eight new locations for the endangered New Mexico Meadow Jumping Mouse (Zapus luteus luteus) detected across three states that expand their known distribution. When combined with existing curated museum records, we develop an ensemble species distribution model to evaluate persistence of populations over the next 50 years. Predicted distributions indicate complex future changes, including regional expansion and the likelihood that half of the designated critical habitat areas will be unsuitable by 2070. Three of the newly discovered populations occur where predicted climate conditions suggest extirpation is likely. Importantly, indices of historical sampling efforts show that recognized and potential distributions are mismatched, highlighting vast areas that have been insufficiently surveyed. Ongoing habitat degradation and climate disruption are projected to synergistically erode genetic diversity across four of the five divergent phylogroups. Considering these combined results, a holistic sampling strategy is needed to more completely document the distribution of jumping mice and facilitate genomic analyses aimed at establishing a roadmap for improving our understanding of geographic variation and adaptive potential. Current management efforts are not only costly, but they are lacking key biological insights, essentially wagering actions with an incomplete deck of cards.

Sex allocation theories predict that under different ecological conditions the production of sons and daughters will affect parental fitness differently. Skewed offspring sex ratios often occur under captive conditions where individuals are exposed to nutritional and social conditions that differ from nature. Here, we analyzed 29 years of offspring sex ratio data from a captive population of an endangered marsupial, the Numbat (Myrmecobius fasciatus). We partitioned variation in offspring sex ratio based on parental origin (captive- vs. wild-bred), parental weight, maternal age, and maternal reproductive history. Our analyses revealed no effect of parental weight or maternal origin on offspring sex ratio—however, there was a significant effect of paternal origin. Data visualization indicated that captive-bred males tended to produce male-biased litters. We discuss the result in relation to recent studies that have shown that male mammals have the capacity to be arbiters of sex allocation and highlight candidate mechanisms, but consider it with caution due to the small sample size from which the result was derived. We performed a population viability analysis (PVA) to explore the potential impact of a sex ratio skew on the sustainability of the captive Numbat population under hypothetical scenarios. Our PVA revealed that supplementation with wild individuals is critical to the persistence of the captive Numbat population and that a biased sex ratio will lead to extinction of the captive colony under certain conditions. Overall, our study demonstrates that covert sex ratio skews can persist undetected in captive populations, which have the potential to become impactful and compromise population sustainability under changed management processes.

Captive breeding is often used to produce individuals for reintroduction programs in order to reestablish a species in an area where it has become locally extinct. To maximize the likelihood of establishing a self-sustaining population in the wild, an analysis of data from captive breeding programs is commonly undertaken to (1) increase the quantity of individuals and rate at which they can be released, and (2) maintain or improve the genetic and phenotypic quality of individuals. Here we demonstrate how the knowledge gained from these analyses can also be applied to decision-making during the design of subsequent reintroductions to further advance a reintroduction program toward success. We conducted an analysis of data from a captive breeding program for the threatened pookila (Pseudomys novaehollandiae, New Holland mouse) spanning 6 years. We found evidence for relationships between the reproductive output of pookila and behavioral, demographic, experiential, health, and physiological predictors. Based on a biological interpretation of these results, and with reference to a checklist of all known translocation tactics, we recommend 11 specific design elements to maximize the probability of pookila reproduction postrelease (thereby improving the likelihood of reintroduction success). These recommendations should be interpreted as hypotheses to be evaluated and refined in future reintroduction trials for the pookila. The uncertainty around the postrelease survival and reproduction of a species that is common in reintroduction practice warrants the creative use of existing data to inform adaptive management. Indeed, there is a wealth information in well-kept captive breeding records that is currently underused by reintroduction practitioners. The direct integration of knowledge derived from captive breeding (where available) with decision-making for reintroductions, as described here, will help navigate these uncertainties, which would benefit the conservation of both understudied and well-known species around the world.

As currently understood, the genus Nyctinomops contains four species: N. aurispinosus (Peale, 1849), N. femorosaccus (Merriam, 1889), N. laticaudatus (É. Geoffroy St.-Hilaire, 1805), and N. macrotis (Gray, 1840). Only N. macrotis and N. laticaudatus have been recorded from Argentina. We found that specimens of Nyctinomops captured in the province of Misiones, Argentina did not correspond to the characters of either species known from Argentina, and did not match characters of any other known species. Morphological, morphometric, and molecular analyses of these specimens revealed that they represent a new species, which we describe herein.

Como se entiende actualmente, el género Nyctinomops contiene cuatro especies: N. aurispinosus (Peale, 1849), N. femorosaccus (Merriam, 1889), N. laticaudatus (É. Geoffroy St.-Hilaire, 1805) y N. macrotis (Gray, 1840). Para Argentina, sólo fueron registradas N. macrotis y N. laticaudatus. Encontramos especímenes de Nyctinomops capturados en la provincia de Misiones, Argentina, con caracteres que no corresponden a ninguna de las especies presentes en Argentina ni a las otras especies descriptas para el género. La revisión de la morfología y los análisis morfométricos y moleculares de los ejemplares revelan que corresponden a una nueva especie que se describe en este trabajo.

The patterns of recovery from injury or infection are not well studied in free-ranging animals. Bats that survive the fungal disease white-nose syndrome (WNS) often emerge from hibernation suffering from skin infections and wing damage. The extent of wing damage reflects physiological and immunological responses to WNS and may impact the ability of bats to fly, forage, and reproduce. Here, we built on previous studies of wing damage in both captive and free-ranging bats to better understand the patterns and extent of wing damage healing in little brown bats (Myotis lucifugus) post-hibernation. We quantified two main types of wing damage, black necrotic dots and white spots, and used the extent of damage to assign bats 1 of 6 wing damage scores. We found that the patterns of black dots and white spots on wing membranes of free-ranging bats aligned with the patterns observed in captive bats soon after emergence from hibernation. Black dot extent was highest at the beginning of the active season in May, while white spot extent peaked 3–4 weeks later. Our study also extends our knowledge of wing damage healing throughout the active season. Wing scores of bats recaptured within the summer decreased or stayed the same and >95% had negligible signs of wing damage by August. We found that black dots were more indicative of disease status than other types of wing damage and could be consistently quantified in the field and from photographs by multiple observers. These results suggest that black dots and our wing damage scoring system can be used to better understand the patterns of post-hibernation healing in little brown bats impacted by WNS.

Long-distance movements (LDMs) of small mammals (SMs) are complex phenomena that cover both dispersals and excursions occurring outside the home ranges of individuals. Owing to methodological difficulties, there are a lack of data on LDMs for SMs. In this study, we aimed to determine the factors that influence the LDMs of different mouse-sized rodents and shrews in the Ural taiga (Sverdlovsk region, Russia). We conducted a field experiment in a boreal forest using individual- (capture–marking–recapture [CMR]) and group- (biomarkers: tetracycline and rhodamine B) marking methods, in conjunction with additional feeding. The species, sex, maturity, plot ID, additional food supply, species abundance indices, individuals/100 trap-nights indices in the capture plot, and body weight of each animal were analyzed as predictors of LDMs. We identified 89 individuals from six species that moved at distances of 250, 350, and 500 m. LDMs varied with the particular species and its population abundance. Most of the observed movements were excursions and not dispersal events. Applying mathematical simulations to the obtained empirical data facilitated estimation of the intensity of the excursion activity for different species. We present the 1st excursion data on Sylvaemus uralensis (Pallas, 1811), Microtus arvalis (Pallas, 1778), and Sorex caecutiens (Laxmann, 1788). The detected excursion distance (250 m) for Myodes glareolus (Schreber, 1780) is the maximum excursion distance known for this species. We demonstrate that with comparable labor and time costs, the use of biomarkers makes it possible to detect many more LDMs than CMR allows.

Co-occurrence of species with similar ecological requirements could bring individual advantages, but when resources are scarce, co-occurring species would segregate to reduce competition and thus enable coexistence. We studied co-occurrence, group dynamics, and activity budgets, along with the seasonal and diel variation, of two sympatric species: the Common Dolphin (Delphinus delphis) and Dusky Dolphin (Lagenorhynchus obscurus), in Northern Patagonia, Argentina. Dolphin groups were recorded by nautical surveys between 2006 and 2018, and classified the groups by their constituent species (single- or multispecies groups), group size, age/sex composition, predominant activity, season, and time block. Frequencies were arranged in contingency tables and analyzed by log-linear models. Activity bout duration also was recorded by focal-group follows and compared using nonparametric tests. Single- and multispecies groups' occurrence varied throughout the year, with a period of high co-occurrence in spring and summer, when both species and most of multispecies groups were present, and a period of low co-occurrence, when mostly common dolphins remained in the area. Common dolphins occur in groups of more than a hundred while dusky dolphins do so in groups of 50 animals at most. Feeding time budget was higher in Dusky Dolphin single- and multispecies groups. Common dolphins showed a seasonal and diurnal pattern in activity budget. During the period of high co-occurrence, dusky dolphins' group size showed a diurnal pattern, and both species increased their feeding time budgets, a putative indication of more favorable foraging conditions. During this period, dusky dolphins associate occasionally in multispecies groups, increasing feeding time budget and feeding bouts duration, suggesting that the association between the two species is beneficial.

La co-ocurrencia de especies con requerimientos ecológicos similares puede dar lugar a ventajas, pero cuando los recursos son escasos, las especies se segregarían para así disminuir la competencia y permitir la coexistencia. Estudiamos la co-ocurrencia, dinámica de grupos y patrones de actividad, junto a su variación estacional y diaria de dos especies simpátricas: el delfín común (Delphinus delphis) y el delfín oscuro (Lagenorhynchus obscurus), en el norte de Patagonia, Argentina. Se realizaron relevamientos náuticos entre 2006 y 2018, registrando grupos de delfines que se clasificaron según su composición de especies (mono o multiespecíficos), tamaño de grupo, composición en clases de edad y sexo, actividad predominante, estación y bloque horario. Las frecuencias fueron dispuestas en tablas de contingencia y analizadas usando modelos log-lineares. Mediante seguimientos de grupo focal, se calculó la duración de los eventos de cada actividad y se compararon mediante pruebas no paramétricas. La ocurrencia de los grupos mono y multiespecíficos varió a lo largo del año, distinguiendose un periodo de alta co-ocurrencia en primavera y verano, cuando estuvieron presentes ambas especies y la mayoría de los grupos multiespecíficos, y un período de baja co-ocurrencia, en que principalmente se encontraron grupos de delfines comunes. Los delfines comunes se vieron en grupos de varios cientos de delfines como máximo, mientras que el mayor tamaño de grupo de delfines oscuros fue de 50 animales. El tiempo de alimentación fue mayor en los grupos de delfines oscuros y multiespecíficos. Los delfines comunes mostraron un patrón diario y estacional en el presupuesto de actividad. Durante el periodo de alta co-ocurrencia, el tamaño de los grupos de delfín oscuro varió con la hora del día, y ambas especies aumentaron su tiempo de alimentación, lo cual indica condiciones favorables para el forrajeo. Durante este período, se asociaron ocasionalmente en grupos multiespecíficos, aumentando el presupuesto de tiempo de alimentación así como la duración de eventos de alimentación. Esto sugiere que la asociación entre las dos especies es beneficiosa.

Plateau pikas (Ochotona curzoniae) play a keystone role in the alpine meadow ecosystem on the Qinghai–Tibetan Plateau (QTP). For decades, alpine meadows on the QTP have suffered from severe degradation, predominantly due to livestock grazing and frequent dramatic increases in plateau pikas. The cause has long been thought to be that livestock grazing provides open habitats for pikas. However, open habitats with low food nutrient quality are insufficient to maintain high-density populations. Feeding facilitation is a process or action undertaken by one species whose activity benefits another species. However, the facilitative effects on population consequences remain unclear. Here, we examined the impact of feeding facilitation on the population dynamics of plateau pikas. We hypothesize that the high protein amount provided by meadows that have been overgrazed would be an important factor leading to dramatic increases in plateau pikas. We found that plateau pikas preferred high-protein foods, and relatively abundant high-protein food resources were found in meadows following high levels of livestock grazing. Body mass and amount of protein in stomach digesta of pikas were higher in moderately and heavily grazed meadows than in lightly grazed meadow. Thus, pika population density was associated with high-protein food resources. A supplemental protein experiment confirmed that high-protein foods led to higher pika population density by increasing reproductive performance. Livestock grazing increased the abundance of plateau pikas by shifting plant nutrient contents toward higher protein conditions favorable to them. Feeding facilitation is an important factor that causes a dramatic increase in plateau pikas.

Wildlife monitoring plays a key role in species conservation, with growing importance under the threat of climate change. The Northern Pika (Ochotona hyperborea) is a cold-adapted species found in Hokkaido, Japan, presumably vulnerable to such threats. However, its high elusiveness hinders detailed population surveys, and visual detection methods—often used for other pika species—are not applicable to its densely vegetated habitats. In this study, we assessed the efficacy of aural detection methods to survey the occupancy of Northern Pika through their distinct vocalizations. We conducted two types of point-count surveys—auditory observation and playback—during 2021 at 18 sites in and around Daisetsuzan National Park. We then assessed the efficacy of these methods in detecting presence and compared time until first detection of the animal. The Northern Pika was present at 11 of all surveyed sites, with a predominance at higher elevations. Our results suggest that both auditory observation and playback are effective at detecting presence, but playback is more time-efficient. We discuss the advantages and disadvantages of each method given these results. In conclusion, our results demonstrate that both survey methods are applicable for Northern Pika population surveys—even in densely vegetated habitats—representing valid and affordable survey methods that can help to improve current monitoring and conservation efforts, and will be of increasing value given potentially negative effects of climate change on persistence of the species.

Measures of fecal bacterial abundance and taxonomic composition are commonly used as proxies for gut microbial diversity in studies of free-living mammals. Because methods of sample collection and storage may affect measures of bacterial diversity, we evaluated the effects of several procedures on fecal bacterial diversity in a free-living population of California ground squirrels (Otospermophilus beecheyi). Replicate fecal samples from 12 adult female squirrels were collected either from the soil beneath traps in which individuals had been captured or from tubs placed under squirrels during handling. Samples were then either frozen immediately in liquid nitrogen or stored on ice for several hours before being transferred to a –80°C freezer. Sequencing of the bacterial 16s RNA gene revealed no differences among methods with regard to sequence read depth (number of sequences recovered per animal) or alpha (within-individual) diversity of bacterial taxa. While our collection-storage procedures had a significant effect on one of the metrics of beta (among-individual) bacterial diversity examined, this effect was small compared to that of individual identity. Date of sample collection affected alpha and beta diversity; samples collected only 1 week apart differed significantly in bacterial diversity. Overall, these findings suggest that the collection and storage methods employed yield generally comparable information and are capable of capturing potentially important patterns of fecal bacterial composition and diversity in free-living mammals.

La abundancia de bacterias y composición taxonómica en muestras fecales son medidas comúnmente utilizadas para evaluar la diversidad de microbiomas intestinales en estudios de mamíferos de vida libre. Debido a que métodos de colección y almacenamiento de muestras pueden impactar las medidas de diversidad bacteriana, evaluamos los efectos de diferentes métodos en la diversidad bacteriana en muestras fecales en la población de vida libre de la ardilla de tierra de California (Otospermophilus beecheyi). Réplicas de muestras fecales de doce hembras adultas fueron colectadas tanto del suelo debajo de las trampas o de los contenedores de plástico donde se llevó a cabo el manejo de las ardillas. Las muestras fueron congeladas inmediatamente en nitrógeno líquido o almacenadas en hielo por varias horas, antes de transferirlas a un congelador a –80°C. La secuenciación del gen bacteriano 16s RNA, no mostró diferencias en los métodos con respecto a la profundidad de secuenciación (número de secuencias recuperadas para cada animal) o la diversidad alfa de los taxa bacterianos (dentro de cada individuo). Sin embargo, nuestro protocolo de colecta-almacenamiento tuvo un efecto significativo en una de las métricas examinadas de diversidad bacteriana beta (entre individuos), siendo un efecto pequeño en comparación con la identidad individual. Asimismo, la fecha de la colección de la muestra afectó la diversidad alfa y beta; donde las muestras colectadas sólo con una semana de distancia muestran una significante diferencia en la diversidad bacteriana. En general, estos resultados sugieren que los métodos de colección y almacenamiento empleados producen información comparable y son capaces de potencialmente capturar importantes patrones de composición y diversidad bacteriana en muestras fecales en mamíferos de vida libre.

We report an elevational record for the Andean sigmodontine Puna Mouse Punomys, which is also the first record of the genus in Chile. The record is based on a mummified specimen that we discovered at an elevation of 5,461 m (17,917 feet) in the caldera of Volcán Acamarachi, Región de Antofagasta, Chile. Results of a morphological assessment suggest that the specimen can be provisionally referred to the species P. lemminus. This new record also extends the known geographic distribution of the genus by 700 km to the south and brings the known Chilean mammal richness to a total of 170 living species and 88 genera. This finding highlights the need for increased survey efforts in more remote, high-elevation regions and demonstrates that there is still much to be learned about the mammal fauna of the Andean Altiplano.

Se reporta un registro altitudinal para el roedor sigmodontino Punomys, el cual corresponde a su vez al primer hallazgo del género para Chile. Este se basa en un espécimen momificado encontrado a una elevación de 5,461 m en la caldera del Volcán Acamarachi, Región de Antofagasta, Chile. Los caracteres morfológicos sugieren que el espécimen puede ser referido provisionalmente a la especie P. lemminus. Este nuevo registro amplía la distribución geográfica conocida del género en 700 km al sur, y eleva la riqueza de mamíferos vivientes chilenos a un nuevo total de 170 especies y 88 géneros. Este hallazgo resalta la necesidad de aumentar los esfuerzos de prospección en las regiones más remotas y de mayor altitud y demuestra que aún queda mucho por aprender sobre el ensamble de los mamíferos del Altiplano andino.

The American Society of Mammalogists (ASM) currently has 13 Restricted Funds intended to make financial resources available to support the mission of the Society by providing grants and awards to students, early-career mammalogists, and members who perform activities relevant to ASM. Restricted Funds are specified to support a Society objective or area of research. When initially established, the originator(s) defined the use of a Restricted Fund. However, descriptions and requirements of each Restricted Fund are not often stored in a readily available location or format making it difficult for potential applicants to determine how to proceed. We collected information on each Fund from journal articles, book chapters, minutes of ASM Board of Directors meetings, and personal communications from ASM members. Then we compiled information relevant to each Restricted Fund to centralize this information and make available the intended purpose of each Restricted Fund. Several of the Funds have reached a level to be self-sustaining at the current award amounts, but others remain in desperate need of funding to be able to support the intentions of the originators. Mammalogists recognize through their establishment of Restricted Funds that allocations from these Funds are instrumental in supporting the development of students and junior colleagues as they hone their science and contribute to the science of mammalogy.