Climate change can have a large impact on the population dynamics of many species. Shifts in precipitation can affect plant community composition and primary productivity, especially in arid and semi-arid environments, and hence trigger cascading changes in resources availability for herbivores. Resource availability, in turn, alters small mammal (e.g., rodent) fitness and population dynamics.

Although the bottom-up effect of precipitation on rodents has been well documented, few studies have evaluated the relationship between precipitation and rodent populations using manipulative field experiments. Likewise, field studies rarely identify the physiological mechanisms causing the bottom-up regulation of plants on rodents, or examine the role of host-microbiota interactions in this regulation.

Prof. ZHANG Zhibin's team from the Institute of Zoology of the Chinese Academy of Sciences found that climate change could shape the population of vole by regulating the composition and metabolism functions of vole's gut microbiota.

The researchers found precipitation supplementation facilitated the recovery of a perennial rhizomatous grass (Leymus chinensis) species, which altered the diet composition and increase the intake of fructose and fructooligosaccharides for Brandt’s vole. Results were published in a paper titled "Host-microbiota interaction helps to explain the bottom-up effects of climate change on a small rodent species" in the ISME Journal.

Lab results showed that this nutrient shift was accompanied by the modulation of gut microbiota composition and functional pathways (especially for the degradation or biosynthesis of L-histidine).

Particularly, the relative abundance of Eubacterium hallii was consistently increased after feeding voles with more L. chinensis, fructose or fructooligosaccharide. These modulations ultimately increased the production of short chain fatty acids (SCFAs) and boosted the growth of vole.

This study provides evidence that the precipitation pulses cascades through the plant community to affect rodent gut microbiome. The results highlight the importance of considering host-microbiota interaction when investigating rodent population responses to climate change.

Fig.1 Rainfall supplementation experiment in Research Station of animal ecology in Inner Mongolia, China (Image by IOZ)