Environment Drivers Acting on Rodent Rapid Morphological Change

Abstract

Rapid Morphological Changes (RMCs) in rodents has been frequently documented. However, relation between RMCs and potential environmental drivers has been understudied. Here, we utilized a museum collection of four rodent species, collected in the same Atlantic Forest fragment, to investigate variation in the skull morphology over time, and test the influence of environmental and diversity drivers in RMC. We tested differences in size and shape of the skull between specimens collected in two temporal series, 1992–1997 and 2009–2010. For size, we tested differences over time in 20 cranial measurements within each species with independent-samples t-tests. To test shape variation, we performed a PERMANOVA with data generated by 13 landmarks on the dorsal view and another 13 on the ventral view throughout two-dimensional geometric morphometrics. We also explored the best relationships between cranial changes and five drivers of climate and two of rodent diversity by Akaike model selection. Our analysis showed RMCs in all studied species and theses changes were strongly influenced by tested drivers. The best model included only maximum temperature showing a negative association with size. Other tested models that presented similar fit showed that precipitation, humidity, richness of rodents, and minimum temperature had a positive association with size. Additionally, abundance also was negatively associated with morphological changes in the most abundant and the largest of the sampled species. The results indicated these species seem to quickly respond to environmental changes. Understanding which species have the potential to adapt to changes is central for the future of biodiversity conservation.