Volume 90, Issue 2 - Special Issue: Mammalian adaptations and responses to high elevation in the face of climate change; Issue Editors: Peter J. Taylor and Christiane Denys

Mitochondria provide most of energy in animal cells through oxidative phosphorylation; therefore, the evaluation of selective pressures on the mitochondrial genome can yield valuable insights into evolution of adaptations to different energy requirements within unique environments. The distribution of East African shrews is directly related to an altitudinal gradient, implying their high level of adaptive divergence and making them a unique model for revealing molecular mechanisms of the adaptation. Here we analysed signs of adaptive evolution in 17 mitogenomes of endemic Ethiopian white-toothed shrews (three ecotypes of Crocidura glassi s.l.) that replace each other in adjacent altitudinal belts of the Bale Massif, possibly indicating large adaptive divergence. To test this hypothesis, we used a combination of different methods besides classic tests of selection; we also analysed physicochemical changes of amino acid properties in protein-coding genes. None of the analyses yielded significant results on positive selection. We can theorize that purifying selection might have been a common selection pattern for mitochondrial genes in C. glassi s.l. ecotypes. Finally, different environmental adaptations – reflecting organisms’ various strategies and possibly important in white-toothed shrews – are discussed.

Recent studies have shown that Mus imberbis , formerly known as Muriculus imberbis , is an internal lineage of the African subgenus Nannomys . Due to differences in coloration between specimens from the Abyssinian Plateau and Harar Plateau of the Ethiopian Highlands, populations from the Harar Plateau have been given subspecies status. Nonetheless, available data have been insufficient to assess phylogenetic structure of this species. In this work, we reconstruct phylogeographic structure of M. imberbis on the basis of molecular data. The obtained results refute the division of M. imberbis into two subspecies. We also describe for the first time the karyotype of this species.

Monotypic genera (MTGs) hold significant evolutionary value, as their extinction results in the loss of an entire lineage. Given their frequent endemism and restricted distributions, particularly in mountainous regions, MTGs may be disproportionately vulnerable to climate change. In this study, we evaluated the extinction risks of rodent MTGs globally, considering three key factors: (i) proportion of range in mountains, (ii) habitat niche breadth, and (iii) proportion of range in high climate change areas, using a 2080–2099 published scenario. Using IUCN-based assessments and principal component analysis (PCA), we identified 41 MTGs at high risk, with the Oriental region – especially Sulawesi – emerging as a hotspot. While 36.6 % of high-risk MTGs were strictly montane, our multivariate analysis revealed a weak correlation between the proportion of the range within mountainous regions and the percentage of the range located in areas experiencing rapid climatic change, with eleven genera (e.g., Nilopegamys, Eupetaurus, Aeretes, Hodomys ) being positioned near the axis representing the proportion of their range situated within high climate change zones. The impact of niche width appeared to be minor with relatively few genera being habitat specialists. The most affected genera were primarily Muridae, occurred predominantly in the Oriental region, and often had extremely narrow distributions. Conservation efforts should prioritize regions with high-risk MTGs, particularly Sulawesi, Sichuan (China), Ethiopia, and Mexico.

Climate change is affecting biotic conditions at high altitude, particularly for species with narrow habitat preferences. Among them is the Andean rodent Aconaemys fuscus , known only from its holotype, collected in Argentina more than 150 years ago. Surveys in its purported habitat, including those conducted in 2017, have failed to detect the species and instead have documented the presence of another caviomorph, Ctenomys . Glacier recession, reduced snow precipitation, and increased grazing pressure on highland wetlands in the Central Andes suggest that A. fuscus may have been extirpated from the region due to climate change.

The Ethiopian Highlands (EH) represent one of the most outstanding centres of endemism in Africa. There is an important biogeographical structure of EH, driven by the presence of the Great Rift Valley (GRV) and deep river valleys, promoting diversification of biota. Here we focused on small mammals of the Wolaita and Gamo zones in the southern part of EH, eastward of GRV. We DNA-barcoded all taxa and combined the new data with previous sequences from other parts of EH and elsewhere. Based on the phylogeographic patterns, we assess the role of GRV in southern Ethiopia as a barrier to gene flow (in montane taxa) or as a corridor facilitating gene flow (in lowland taxa from savanna). We show that the bottom of GRV is inhabited by a unique mix of taxa from the Sudanian and Somali-Masai savannas. The mountains are inhabited (i) by species widely distributed on both sides of GRV, (ii) by species restricted to remnant forests of south-western EH, and (iii) by specialists of Afroalpine habitats, including one possibly new species of Lophuromys . The high diversity of indigenous ecosystems is significantly threatened by an increasing human population and by invasive commensal mammals, mainly the black rat Rattus rattus .

Bennett’s chinchilla rat ( Abrocoma bennettii ) is an hystricomorph rodent endemic to Chile inhabiting semi-arid and mediterranean regions below 2,000 m above sea level, from northern and central Chile. Using various lines of evidence, including camera traps, skulls, middens, and DNA, this study reports two new records of A. bennettii discovered during the course of a baseline fauna survey. These new records expand their current altitudinal limit up to 3,500 m above sea level and reveal an unprecedented potential sympatry with Abrocoma cinerea in the Andes of the Atacama Region, highlighting the ecological versatility of this common yet elusive rodent.

Bats are among the most phylogenetically diverse and ecologically significant mammalian groups, comprising ca. 22 % of all mammal species. They provide ecosystem services, including insect pest control, pollination, and seed dispersal of agriculturally important plants. As bioindicators, their population status offers insight into ecosystem health, particularly in fragile environments such as cave systems. We investigated bat diversity and composition in sandstone and limestone caves in the Tigray Region, Ethiopia, based on surveys conducted from December 2016 to April 2017 and March to October 2020. Using morphological and genetic identification, from 15 sampling sites we recorded 151 individuals representing 10 species from five families. While four species, Nycteris macrotis 1, N. sp., Plecotus balensis , and Hipposideros megalotis , were restricted to either sandstone or limestone caves, Hipposideros tephrus , Rhinolophus blasii , and Nycteris thebaica occurred in both, suggesting broader ecological valence. Notably, P. balensis , the Ethiopian Highland endemic bat, was recorded in a cave for the first time, extending its known distribution northward. Given the extensive network of caves and rock-hewn churches in Tigray, a comprehensive inventory of the region’s bat fauna is essential for evidence-based conservation. With increasing anthropogenic pressure from tourism and habitat degradation, protecting key roosting sites is vital for sustaining bat populations.

This study aimed at understanding the effects of hydrology on the activity pattern of the Pyrenean desman. Fourteen individuals were monitored by radiotracking in six rivers having different hydrology. Several metrics describing aquatic activity were assessed to study variability among individuals. First, whatever hydrology, individuals had a similar average daily activity. Individuals which experienced the greatest variations in flow during monitoring and which were radiotracked in autumn tended to be more or less active depending on days. Second, several patterns of activity were observed. Individuals monitored at a flow value close to the mean annual flow in summer tended to be mainly active at night and to travel a larger distance along the river. Individuals monitored during periods of low or high flows tended to be more active during daytime and to travel smaller distance. Finally, some individuals had consistent daily activity throughout the monitoring period, while others showed some variability. These differences are not related to hydrology or other variables studied but the highest intra-individual variabilities were observed during significant flow variations. These findings provide new information on the ecology of the Pyrenean desman and will help to improve management and conservation actions.

Advance in the phenology of plants and animals is a widely observed response to climate change. The magnitude of the changes is, however, very variable across species. Several biological factors could influence the strength of the phenological advances, including lifestyle. Hibernation has evolved in response to harsh environmental conditions and could, hence, potentially buffer organisms against changing climatic conditions. In the Alps, the Alpine marmot hibernates for almost 6 months. Owing to its slow pace-of-life, we expected Alpine marmots to be more responsive to earlier springs than non-hibernating species. Here we investigate temporal variation in the date at which pups emerge from their natal burrow for the first time. Using quantile regressions, we provide clear evidence of an earlier pup emergence between 1990 and 2023. Over the study period, the predicted change is 4.7 days. In particular, late emergence dates are becoming especially rare over time. Our findings are in line with previous works on other Alpine species, which suggest a general advance in reproductive phenology. The rate of change of pup emergence dates over years is, however, weaker in the Alpine marmot than in most other mammalian species studied so far.

Climate change is altering phenological traits across many taxa. While northern temperate species often adjust migration or breeding to track these shifts, such adjustments may be insufficient, leading to mismatches between trophic levels. Most studies focus on changes in the timing of spring onset, but few assess how climate change affects the speed of seasonal changes. Rapid spring green-up can shorten the period of high-quality forage, potentially constraining herbivore nutrition. We investigated how both the timing and duration of vegetation green-up influence body mass in bighorn sheep ( Ovis canadensis ). Using 23 years of satellite-derived Enhanced Vegetation Index (EVI) data, we quantified the onset, date of maximum green-up rate, and end of green-up, and assessed their effects on lamb weaning mass and female autumn mass. Green-up occurred increasingly early over time, but its duration showed no consistent trend. Green-up date weakly affected female mass, whereas neither green-up date nor duration influenced lamb weaning mass. These findings suggest that while shifts in timing are detectable, their demographic effects are limited. Future research should consider not only the onset of vegetation growth but also its rate and the timing of browning down, as both can shape forage availability and herbivore performance.