Mammalian Biology最新文献

Over the last century, a significant decline in the population size of the Nubian Capra nubiana has been observed across its distribution range. This decline is attributed to the changes in natural resources, including water and foraging site capacity, due to the ongoing climate change. We applied species distribution models (SDMs) to investigate the response of C. nubiana to projected climate change in the next decades. We fitted ensemble SDMs with recently developed climate data based on climate models and two different dispersal scenarios to minimize the uncertainty and bias in our SDMs prediction. Our SDMs predicted a significant shrinkage of the distribution range of the C. nubiana in the coming decades, where C. nubiana may lose ca. 60% of its area of occupancy before 2050, while it may become extinct (lose > 90% of its projected area) before the end of the current century. Our results call for urgent conservation intervention at global and national scales to halt the impact of climate change on one of the remaining top mountain ungulate species in desert ecosystems.

Among human activities agriculture is one of the main drivers of biodiversity loss worldwide in recent decades. The effects of agricultural intensification on vertebrate populations may vary depending on their habitat requirements. The effect of environmental and/or genetic stress on populations can be assessed using fluctuating asymmetry and body condition of animals. We implemented both linear and geometric morphometric methods to assess the influence of agricultural intensification on three native rodent species. For this, we evaluated different stress indicators on skulls and mandibles (fluctuating asymmetry, centroid size and scaled mass index) of three species of small mammals at borders of rural roads in agroecosystems in central Argentina. We explored the impact of intensification using variables at different scales: landscape level, assessing complexity through functional and structural heterogeneity; and local level, through vegetal volume of the border. We found species-specific responses, where the most sensitive species was Calomys venustus, which showed individuals with lower developmental stability and body condition in simple landscapes and low-quality habitats. Akodon azarae responded in an intermediate manner to both size and mass index indicators, while the species Calomys musculinus was the least affected, with changes only in body condition observed, with larger individuals in more complex landscapes. Our results suggest that the impact of agricultural intensification on small mammals varies according to their habitat requirements and the landscape heterogeneity. This study shows the importance of considering both local and landscape variables to propose management measures for biodiversity conservation in cropland anthromes.

The American mink (Mustela vison) is known as a successful non-native species in Europe, impacting native species’ population sizes and habitats. This study investigates the genetic structure and diversity of American mink populations in France over two decades (1997–2016). The analysis involves feral and farmed mink sampled from various regions, using ten autosomal microsatellite loci for genotyping. The objective is to identify the putative existence of genetic lineages, especially between feral and farmed individuals, and to assess changes in genetic structure over time. Results reveal high genetic diversity and inbreeding within populations, with evidence of genetic structure influenced by both farm releases and feral colonization. The study highlights the reflection of the genetic structure in farm populations in the feral populations within the first period (1997–2007), and a decline of a lineage over time in the second period (2007–2016) with the emergence of a new genetic cluster, potentially influenced by factors such as selection, phenotypic changes, and interactions with pathogens. Overall, this research contributes to the understanding of the dynamics of American mink populations in France and their genetic variability, emphasizing the importance of ongoing monitoring and management efforts to mitigate the impact of this invasive species, especially on endangered or/and endemic species such as European mink (Mustela lutreola) and Iberian desman (Galemys pyrenaicus).

Much remains to be established about the socio-ecology and mating system of the soft-furred tree mouse, the Typhlomys species, only genus of rodents confirmed to have evolved echolocation. In this study, we examined sexual size dimorphism (SSD) in T. daloushanensis to gain insight into its as yet unknown mating system. Sexual selection has been generally theorized to drive male-biased SSD among mammals, linked to male competitiveness in polygynous mating systems. We live-trapped 212 adults from Xingshan County in Hubei Province from 2021 to 2023 and supplemented this dataset with 67 individuals measured during a previous study. Our findings revealed a significant male-biased sexual size dimorphism, with males exhibiting notably greater body length (+ 4.3%) and body mass (+ 16.7%) compared to females. This suggests that the larger size may provide an advantage to male T. daloushanensis in competition for access to females (i.e., the Darwin-Bateman-Trivers paradigm), implying the likelihood of a polygynous mating system, although monogamous and promiscuous mating strategies should also be considered in future research. Additionally, ANCOVA analyses revealed that males had significantly longer ears and forefeet than females, beyond allometric scaling. This may indicate a functional basis to specific trait sexual dimorphism linked to differences in agility and auditory perception in this echolocation species. Our first report of male-biased SSD in T. daloushanensis suggests directions for future research to expand understanding of this little-known, echolocating mice, and adds further data on SSD in the Muroidea.

Fires are becoming increasingly frequent, intense, severe and prolonged worldwide, and such situation is worsening. As a result, extreme fire conditions will increase, with consequences for wildlife, including increased mass mortality and changes in trophic relationships in natural communities. This intensification is expected to be particularly pronounced in the Mediterranean ecosystems. In this scoping review, we summarized current knowledge and gaps in understanding the effects of fires on wildlife, focusing on predator–prey interactions. These interactions play a critical role in animal communities and their understanding is fundamental for appropriate management and conservation. Mammals were chosen as a model group because of their remarkable ecological role. We grouped and analysed the post-wildfire changes in the predator–prey relationships into three-time intervals: immediate, short- and long-term effects. This is relevant as vegetation restoration, by altering cover and habitat structure, may affect hunting strategies and anti-predatory behaviour. Our review showed that studies generally had several limitations, the most common of which were the lack of replication, the strong geographical bias, and the focus on few target species. Nevertheless, we could formally describe how fire affects predator–prey relationships in Mediterranean ecosystems through processes that exert different cascading effects at different times after the fire event. We encourage long-term studies on communities, including as many components of the food chain as possible, using an interdisciplinary approach, and prioritising investigations in high-risk ecosystems.

The common opossum (Didelphis marsupialis) is a marsupial widely distributed in the Neotropics, where it lives in urbanized environments. The apparent scarcity and fragmentation of available habitat, and high rates of vehicle collisions, may represent barriers to dispersal. To assess the functional connectivity of this species and its potential use as a model in urban ecology, we evaluated the structure and genetic diversity of opossums in the metropolitan area of the Aburrá Valley (AMVA), Colombia, using sequences of the mitochondrial Cytochrome B (Cytb) gene and nine autosomal microsatellite loci. Although Cytb presented low levels of variation, microsatellite markers revealed high genetic diversity (He = 0.852 and Ho = 0.698). The geographic distribution of mitochondrial lineages and a spatial principal component analysis (sPCA) of microsatellites showed the absence of genetic structure and effective barriers to dispersal of opossums in the study area. This scenario suggests that hostile landscapes such as those in urban environments may be suitable enough to allow the effective connectivity of some species such as the common opossum and others with high dispersal ability in urbanized areas. Nonetheless, it is necessary to evaluate the impact of releases of rescued fauna made by the environmental authority on the population structure of urban opossums.

We examined some factors that might allow for the coexistence of two sympatric skunk species, southern spotted skunks (Spilogale angustifrons) and striped hog-nosed skunks (Conepatus semistriatus), in a dry forest of northwest Costa Rica (Santa Rosa Sector of Guanacaste National Park) by comparing distribution of captures and occurrence in cover-types derived from 56 camera traps monitored from June 2016-June 2017, as well as relative activity patterns derived from these and 45 other cameras in the same area monitored irregularly from 2011 to 2016. Photo rates of spotted skunks in our study area were twice those of striped skunks. At no camera were both species photographed over the course of a year, but both species were commonly recorded in the same cover types. Photo rates of spotted skunks, however, were higher than expected in Secondary Forest and lower in Riparian Forest, whereas for striped skunks the rate was higher than expected in Mangrove and Beach Forest. Both species were clearly nocturnal, and the plots suggesting that spotted skunks were more active than striped skunks before midnight, and striped skunks were more active after midnight, were not significantly different. Differences we observed in the distribution of photos by cover types and camara location for the two skunk species were notable and suggest local allopatry, likely the result of interspecific avoidance. Species-specific food habits, predation, and competition with other species may also be an important factor affecting these observations, and other techniques should be used to investigate these factors. Still, cameras can provide important insights into cryptic species’ ecology.

We respond to the note by Russo et al. “Of greater noctule “migration” from Russia to Italy: a comment on Vasenkov et al. (2023)”, which comments on our paper “Vasenkov DA, Vasiliev NS, Sidorchuk NV, Rozhnov VV (2023) Autumn migration of greater noctule bat (Nyctalus lasiopterus): through countries and over mountains to a new migration flight record in bats. Dokl Biol Sci 513:395–399. https://doi.org/10.1134/S0012496623700746” regarding our use of the term “migration”. We used “migration” to describe the long-distance seasonal flights of three greater noctule (Nyctalus lasiopterus) individuals. We chose exactly this term as it is commonly used in a broader sense to refer to bat autumn long-distance flights, when the further fate of these flying bats remains unknown. Russo and co-authors challenge the use of the term “migration” in the context of bat long-distance movements. However, we believe that it is not always easy to efficiently distinguish between cases of dispersal flight and migratory flight.

The earliest mammals are characterized by a series of derived characters when compared to their synapsid predecessors. In comparison to non-mammalian synapsids, these features include highly efficient teeth, a small body size, a parasagittal limb posture, as well as a reduced number of ribs and girdle elements and light-weighted tails. We argue that the mammalian body construction and its functionality are constituted by a set of partially interrelated morphological traits, including akinetic skulls, tooth anatomy, and food processing; body size, locomotor speed, and tail reduction; the posture of the body and the construction of the girdle elements; as well as body torsion and rib reduction. By discussing these features from a biomechanical view, we demonstrate that high speed was the most important evolutionary advantage of the small earliest mammals over their larger synapsid ancestors, as well as over dinosaurs at the end of the Mesozoic.

Sympatric species reduce competitive interactions by segregating their ecological niche as a strategy that promotes coexistence. The main dimensions in which niche differentiation occurs are spatial, trophic, and temporal axes. Thus, describing the spatiotemporal patterns of sympatric species help us better grasp how species coexist. In Mexico, coyotes (Canis latrans) and gray foxes (Urocyon cinereoargenteus) are sympatric and widely distributed, and information about their temporal and spatiotemporal interactions is still needed to explain their coexistence throughout their distribution. The evaluation of the ecological niche in temperate forests where both species coexist has shown high spatial and trophic overlap. Therefore, more pronounced segregation must occur in other niche dimensions, such as temporal and spatiotemporal axes, to maintain the coexistence between coyotes and gray foxes. As an approach to exploring the coexistence between these species in temperate forests, we pose the following question: Is there temporal or spatiotemporal segregation between sympatric coyotes and gray foxes? We hypothesized that both species maintain coexistence due to differences in their daily activity patterns (temporal segregation) and the presence of avoidance behaviors at the spatiotemporal level (spatiotemporal segregation), thereby reducing agonistic interactions. We aimed to evaluate indicators of niche segregation through two approaches: (i) temporal niche partitioning, measuring the overlap of the daily activity patterns and activity levels; and (ii) spatiotemporal niche partitioning, through temporal co-occurrence analysis and time to encounter analysis. In 2018, we used a camera-trap array (n = 43) to evaluate spatiotemporal interactions of coyotes and gray foxes in temperate forests of northern Mexico. We found that coyotes exhibited a diurnal daily activity pattern, whereas gray foxes were nocturnal, showing low overlap between daily activity patterns. Temporal co-occurrence and time to encounter analysis showed that coyotes and gray foxes occurred independently of each other. Therefore, we demonstrated that the spatiotemporal interactions between both species is a result of random species associations. In conclusion, here we provide evidence that ecological segregation occurred in the temporal niche and not in the spatiotemporal niche of the species. Thus, the temporal niche segregation represents one of the ecological strategies that facilitates the coexistence between coyotes and gray foxes and therefore promotes their sympatry in the temperate forests of northern Mexico.