The European rabbit (Oryctolagus cuniculus) has been a remarkably successful invasive species due to its generalist nature and fast reproduction. The rabbit population in Helsinki (Finland) originated from escaped pet rabbits in the late 1980s, and the population expanded rapidly in the early 2000s. The Rabbit haemorrhagic disease (RHD) spread naturally to Finland in 2016, and the disease caused a significant reduction in the Helsinki area population. The aim of this study was to examine the effect of the RHD epidemic on genetic diversity, and on the temporal and spatial population structure of the Helsinki area rabbit population from samples collected before and after the epidemic. We found that genetic diversity in the Helsinki area rabbits is low compared to other wild rabbit populations worldwide. An initial founding effect could be detected in the population, but the effect of the RHD epidemic on genetic diversity was unclear, and there was no obvious bottleneck after it. Interestingly, genetic diversity was higher after the population crash, which may be explained by continuing gene flow from escaped and/or intentionally released pet rabbits. Although the period of separation has been relatively short, the subpopulations have already diverged genetically to some extent, indicating that dispersal is not unrestricted across the study area. There was also a slight allele frequency shift after the RHD epidemic. The European rabbit has become an established member of the Finnish fauna, and eliminating this invasive species would be difficult, as the current population is continually replenished by escaping and intentionally released pet rabbits.
Most species are adapted to navigate the seasonal variations that impact their habitat use and behavior. We can use this baseline understanding of their seasonal responses to understand how they may respond to more extreme and unexpected changes. The canopy structure can provide a buffering effect for arboreal species through vertical microclimatic gradients, creating potential microrefugia. In this study we examine how seasonality impacts the activity and vertical space usage of the nocturnal Bengal slow lorises (Nycticebus bengalensis) in Northeastern Thailand. We collected behavioral and concurrent climatic data from June 2023 – August 2024 and used Bayesian multinomial logistic models for each season to understand the impact of loris height in the tree, temperature, and relative humidity on behavior. We found that temperature had the strongest negative association with activity levels and verticality across all seasons. When temperatures rose above average, slow loris activity declined, suggesting that the buffering effect of lower canopy layers was limited when temperatures exceeded the thermal neutral zone for this species. The lower canopy is a climate microrefugia for Bengal slow lorises, however it depends on upper canopy connectivity. As global temperatures rise due to climate change, it is essential that we maintain forest canopy structure to preserve these microrefugia, especially for nocturnal species that have no cooler period to utilize.
The Central Andes is a global hotspot of biodiversity and endemism and harbor the highest species richness of sigmodontine rodents, one of the most diverse groups of Neotropical mammals. However, the geographical patterns and environmental correlates of genetic diversity in this region remain poorly understood. Here, we compiled a mitochondrial DNA dataset combining newly generated and published Cytb sequences for sigmodontine rodents from the Central Andes and adjacent lowlands. We analyzed 521 sequences from 30 species across 23 altitudinal bands to evaluate variation in nucleotide diversity in relation to elevation and environmental predictors. Nucleotide diversity did not vary significantly among altitudinal bands, whereas substantial differences were observed among species, with no detectable phylogenetic signal. Linear mixed-effects models identified mean solar radiation as the only environmental predictor, showing a positive association with nucleotide diversity. Solar radiation explained 6.3
Trabecular bone is known to adapt to mechanical stimuli, but its adaptive signal is understudied in small mammals. Such studies could, for example, inform previous hypotheses about size-specific scaling patterns. Here we looked at muroid rodents to analyse the effect of body size and locomotor behaviour on the trabecular network of the proximal stylopodia. We used µCT scans of humeri and femora to quantify various trabecular parameters. We found that the trabecular network changes with size, characterised by positive allometric scaling of bone volume fraction, connectivity density, and specific bone surface and negative allometric scaling of trabecular thickness and spacing. When compared with the available literature on scaling within various mammalian taxa, our results add to growing evidence that scaling patterns differ between smaller and larger mammals. We detected no significant differences among locomotor groups, which may reflect the limited sample size. However, some descriptive patterns were apparent. Trends in the femur were more in line with the mammalian literature than those observed in the humerus, but more data is needed to confirm these patterns.
Quaternary climatic oscillations strongly influenced diversification in Palearctic mammals, yet patterns of genetic structure and speciation in Anatolian rodents remain insufficiently resolved. We examined the genetic variation of social voles (Microtus socialis species complex) to clarify their phylogeography and population structure in Anatolia. The mitochondrial (Cytochrome b), nuclear (two exon regions), and microsatellite data were analysed from 264 individuals sampled across 157 localities and combined with available GenBank sequences. Mitochondrial phylogenies revealed two well-supported lineages corresponding to refugial areas in Central and Eastern Anatolia, with divergence dating to the Middle Pleistocene. In contrast, the nuclear markers showed widespread haplotype sharing among taxa, and microsatellite loci detected sympatric admixture between Microtus anatolicus and Microtus irani-schidlovskii species complex at the Taurus Mountains. These results indicate incomplete lineage sorting and mito-nuclear discordance among young evolutionary lineages. The Central Anatolian Plateau likely functioned as glacial refugium for M. anatolicus and Microtus dogramacii, whereas the Mediterranean and Iran-Anatolia biomes shaped the current distribution boundaries. Our findings highlight Anatolia’s dual role as a center of endemism and a contact zone for postglacial expansion, providing new insight into the speciation processes and regional biogeography in Palearctic voles.
