Effect of ENSO‐driven precipitation on population irruptions of the Yangtze vole Microtus fortis calamorum in the Dongting Lake region of China

Abstract

The Yangtze vole (Microtus fortis Buechner, 1889) is a small herbivore species that inhabits lake beaches in the Dongting Lake region along the Yangtze River in Southern China. Its population shows strong oscillations during the wet season due to summer precipitation-induced immigration away from the lake into adjacent rice fields. The effect of El Niño-Southern Oscillation-driven precipitation on population abundance and growth of the vole species is not fully understood. We undertook an analysis of the combined data of 4 time series covering 1981-2006 from 4 different sites and a separate analysis on a single time series (1981-2006) from one site. Our results demonstrate that a dual effect of El Niño-Southern Oscillation-driven precipitation on the population abundance of voles is time-dependent: precipitation in the current year has a positive effect, whereas precipitation in the previous year has a negative effect. The dual effect of precipitation on vole population is well explained by the unique interactions among vole population, precipitation water level and the lake beach habitat around Dongting Lake. We found that drier than average weather of the previous year benefited voles because their breeding habitats, lake beaches, were exposed for long stretches of time. Wet weather was found to increase the number of voles inhabiting rice fields because as the water level of the lake rose they were forced from beaches into surrounding rice fields. Summer precipitation in the Dongting Lake region was found to be positively associated with the sea surface temperature (SST) of the eastern tropical Pacific Ocean of the previous year and winter SST and spring SST of the current year. Annual rates of increase in the vole population of the reconstructed time series are negatively associated with the vole abundance and autumn precipitation of the previous year and winter precipitation of the current years. These results suggest that both extrinsic and density-dependent intrinsic factors may affect population dynamics of the Yangtze voles.

Nonlinear effect of climate on plague during the third pandemic in China

“…also southern China (35). Heavy rain also caused high mortality of the Yangtze voles (Microtus fortis) living in close proximity to Dongting Lake's beaches (36,37), and its population size was found to be negatively correlated with water levels of Dongting Lake (38). Precipitation thus tends to have negative effects on rodent plague hosts in southern China.…”

Can rodent outbreaks be driven by major climatic events? Evidence from cyclone Nargis in the Ayeyawady Delta, Myanmar

“…The outbreak of rodent populations 15 months after cyclone Nargis is consistent with the time it would take for rodent populations in agricultural landscapes to build from a low base after a major weather event. For example, Singleton reported a 12–15 month build‐up of house mouse, Mus domesticus , populations, which reached densities greater than 1000 ha −1 in wheat fields in southeastern Australia, and Zhang et al reported that massive outbreaks of the Yangtze vole, Microtis fortis , in rice fields in southeastern China at Dongting Lake were related to low rainfall the previous year and high rainfall during the year of the outbreak.…”

Small mammal community succession on the beach of Dongting Lake, China after the Three Gorges Project

“…Therefore, the evaluation of the small mammal communities was divided into 4 periods, based on the stage of water storage: (i) before construction in the 1990s (1992-1994, and fragmentary surveys in 1997-1999); (ii) the first partial filling period (2003)(2004)(2005)(2006); (iii) the second partial filling period (2007)(2008); and (iv) during experimental water storage to a final water level of 175 m (2009)(2010)(2011)(2012). Data from each period were pooled for the analysis of community structure, because of the low number of captured individuals of some species, to overcome the issue of occasional surveys in each single investigation, and to smooth the influence of strong oscillations of M. fortis (Zhang et al 2010b). Only 1 sampling site was continuously surveyed in the 1990s (the beach outside of Matang Polder); hence, fragmentary surveys from other locations were pooled with this dataset to provide an overview of the situation before the TGP, allowing overall trap success to be calculated for all nights during which traps were set in each period.…”