Successive sheep grazing reduces population density of Brandt’s voles in steppe grassland by altering food resources: a large manipulative experiment

Abstract

Livestock grazing has shaped grassland ecosystems around the world. Previous studies indicated grazing showed various impacts on small rodents; however, most studies were conducted over 1-2 years without controlling for confounding factors such as immigration/emigration and predation in rodents. Brandt's voles (Lasiopodomys brandtii) are generally recognized as pests because of food overlap with domestic herbivores, but are also important for biodiversity conservation because they provide nests or food to many birds. Fully understanding the ecological relationship between domestic herbivores and small mammals is essential to making ecosystem management decisions. To address these needs, we carried out a field experiment during the period 2010-2013 to assess the effects of sheep grazing on vegetation and the population density of Brandt's voles along a gradient of three grazing intensities by using 12 large-scale enclosures. Responses of Brandt's voles to livestock grazing varied with grazing intensity and year. As compared to the control group, sheep grazing had no effect on vole abundance in the first year but an overall negative effect on vole abundance in the following 3 years. Successive grazing caused decreases in survival and male body mass of voles, but had no significant effect on fecundity. Negative effects of grazing were associated with a grazing-induced deterioration in both food quantity (reflected by biomass and cover of less-preferred plants), and food quality (measured by tannin and total phenol content). Our findings highlight the urgent need for more flexible management of yearly rotational grazing to optimize livestock production while maintaining species diversity and ecosystem health.

Dietary shifts influenced by livestock grazing shape the gut microbiota composition and co‐occurrence networks in a local rodent species

“…The plant abundance and composition were surveyed once a month from May to October. Five 1 × 1 m quadrats in each enclosure were randomly chosen, and the per cent cover, biomass and density of each plant species were recorded (Li, Yin, et al., ). Fresh faecal pellets were collected in September at the time of regular live trapping.…”

“…Asymmetric competitive interactions between sheep and Brandt's voles ( Lasiopodomys brandtii ) have been found in the semi‐arid grassland of Mongolia; the body weight and population density of Brandt's voles largely decreased due to the loss of their preferred forage plants after sheep grazing (Li, Yin, et al., ). Changes in both food quantity and quality are known to affect population dynamics of small mammals (Batzli, ), but, as far as we know, no study has been carried out to examine the grazing‐induced diet–microbiota relationship.…”

Dynamic expressions of hypothalamic genes regulate seasonal breeding in a natural rodent population

“…Brandt's vole ( Lasiopodomys brandtii , Figure a) is a small, nonhibernating, herbivorous and social rodent that is mainly distributed in the steppes in China, the Republic of Mongolia and the Baikal Lake region of Russia (Liu, Yue, Wang, Li, & Cong, ; Wang et al, ; Yue, Wang, Huang, & Liu, ; Zhong, Wang, Zhou, & Wang, ; Zhong, Wang, & Wan, ). Following overt seasonal changes in its habitat (Figure b), Brandt's vole shows strong seasonal breeding and its population size increases dramatically from spring (early March) to autumn (late August) (Zhong et al, ; Zhong et al, ; Li, Hou, Wan, & Zhang, ; Li, Yin, et al, ; Figure c,d). Mass of gonadal glands of adult voles is approximately 20‐fold heavier in June than in October (Liu & Sun, ; Wang, Cong, Wang, & Liu, ).…”

Effects of nitrogen addition and mowing on rodent damage in an Inner Mongolian steppe

“…Indeed, most previous studies of rodent damage in grasslands have focused on the effects of grazing, climate warming, and changes in annual precipitation regime. For instance, rodent survival rates are reportedly higher under heavy grazed management (Harris, 2010;Li et al, 2016;Zhang, Pech, et al, 2003;Zhou, Zhao, Tang, Gu, & Zhou, 2005). Climate warming has aggravated rodent damage through promoting clonal growth of Potentilla anserina in an alpine meadow (Li et al, 2011).…”