The structure and dynamics of insect community in grasslands can be influenced by grazing management
via altered characteristics of plant community. However, attempts to better understand the complex
relationships among plants, insects, and large herbivores is still hampered largely by the interactive
effects of plants, insects, and large grazers on each other. In this study, we test the hypothesis that the
effect of large herbivores on insect abundance is grazer species-specific and pre-grazing plant diversitydependent using an experiment with manipulating four grazing treatments (i.e., control, cattle, goats,
and sheep) at low, intermediate, and high plant diversity levels in a meadow steppe at northeast in China.
We show that grazing significantly increased the abundance of the entire insect community. The
abundance of each insect order responded differently to grazing treatments, with higher abundance of
Orthoptera and Homoptera under sheep grazing, enhanced abundance of Coleoptera and Diptera under
cattle grazing, and reduced Hemiptera abundance, but greater abundance of Lepidoptera under goats
grazing. Thus different treatments profoundly changed insect taxonomic composition. The six most
dominant species (Euchorthippus unicolor, Aelia nasuta, Trigonotylus ruficornis, Curculionidae sp.,
Coccinula quatuordecimpustulata, and Cicadellidae sp.) responded differently to grazing by large
herbivores, with either increased or decreased its abundance. The effects of grazing on insect abundance
were driven by their differential responsive mechanisms for vegetation. More importantly, the effects of
grazing on insect abundance at both order- and species-levels potentially depended on plant diversity
levels of pre-grazing. Our results suggest that different herbivore species should be used in the
background of different plant communities for better conservation of insect community in managed
grassland
The structure and dynamics of insect community in grasslands can be influenced by grazing managementvia altered characteristics of plant community. However, attempts to better understand the complexrelationships among plants, insects, and large herbivores is still hampered largely by the interactiveeffects of plants, insects, and large grazers on each other. In this study, we test the hypothesis that theeffect of large herbivores on insect abundance is grazer species-specific and pre-grazing plant diversitydependent using an experiment with manipulating four grazing treatments (i.e., control, cattle, goats,and sheep) at low, intermediate, and high plant diversity levels in a meadow steppe at northeast in China.We show that grazing significantly increased the abundance of the entire insect community. Theabundance of each insect order responded differently to grazing treatments, with higher abundance ofOrthoptera and Homoptera under sheep grazing, enhanced abundance of Coleoptera and Diptera undercattle grazing, and reduced Hemiptera abundance, but greater abundance of Lepidoptera under goatsgrazing. Thus different treatments profoundly changed insect taxonomic composition. The six mostdominant species (Euchorthippus unicolor, Aelia nasuta, Trigonotylus ruficornis, Curculionidae sp.,Coccinula quatuordecimpustulata, and Cicadellidae sp.) responded differently to grazing by largeherbivores, with either increased or decreased its abundance. The effects of grazing on insect abundancewere driven by their differential responsive mechanisms for vegetation. More importantly, the effects ofgrazing on insect abundance at both order- and species-levels potentially depended on plant diversitylevels of pre-grazing. Our results suggest that different herbivore species should be used in thebackground of different plant communities for better conservation of insect community in managedgrassland
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