Herbivore phenology can predict response to changes in plant quality by livestock grazing

作者：Yu Zhu, G. F. Veen, Deli Wang, Ling Wang, Zhiwei Zhong, Quanhui Ma, Heng Li, Xincheng Li, Duofeng Pan, Elisabeth S. Bakker · 发表于：Oikos · 年份：2020 · DOI：10.1111/oik.07008 · 被引用次数：12 · 研究领域：Ecology and Vegetation Dynamics Studies、Plant and animal studies、Wildlife Ecology and Conservation

Livestock grazing can have a strong impact on herbivore abundance, distribution and community. However, not all species of herbivores respond the same way to livestock grazing, and we still have a poor understanding of the underlying mechanisms driving these differential responses. Here, we investigate the effect of light intensity cattle grazing on the abundance of two grasshoppers ( Euchorthippus cheui and E. unicolor ) that co‐occur in the same grasslands and feed on the same food plant (the dominant grass Leymus chinensis ). The two grasshopper species differ in phenology so that their peak abundances are separated into early‐ and late‐growing seasons. We used an exclosure experiment to monitor grasshopper abundance and food quality in the field under grazed and ungrazed conditions, and performed feeding trials to examine grasshopper preference for grazed or ungrazed food plants in the laboratory. We found that the nitrogen content of L. chinensis leaves continuously declined in the ungrazed areas, but was significantly enhanced by cattle grazing over the growing season. Cattle grazing facilitated the early‐season grasshopper E. cheui , whereas it suppressed the late‐season grasshopper E. unicolor . Moreover, feeding trials showed that E. cheui preferred L. chinensis from grazed plots, while E. unicolor preferred the leaves from ungrazed plots. We conclude that livestock grazing has opposite effects on the two grasshopper species, and that these effects may be driven by g...