放牧干扰下的蝗虫－植物相互作用关系

GRASSHOPPER-PLANT INTERACTIONS UNDER DIFFERENT GRAZING INTENSITIES IN INNER MONGOLIA

本文研究了内蒙古典型草原植物和蝗虫群落在不同放牧强度影响下的多样性、均匀性和丰盛度变化。比较了蝗虫群落与植物群落在放牧梯度上的相互作用关系。研究发现，放牧干扰活动会明显地影响植物和蝗虫群落结构，但蝗虫群落结构的变化趋势并非与植物完全同步。蝗虫与植物间的联系更多地表现在植物起着蝗虫栖息地条件的作用，而并不完全是食料植物的作用。文中对放牧实践与多样性保护的关系进行了讨论。

rasshopper population had been monitored for two years on the different grazing pas-tures of natural steppes in Inner Mongolia,and correlated with floral biomass in these pas-tures. Grasshopper and plant sampling were conducted in three types of vegetation sites. Eachsite was divided into five plots as : ungrazed, lightly grazed, properly grazed, heavily grazedand overgrazed plots along grazing gradients, based on different grazing intensities, Abun-dance and diversity of plant and grasshopper communities in the plots were compared. Totalcalorific values of grasshopper biomass were significantly higher in low biomass pastures,al-though the values reduced in the overgrazed plots of Stipa steppes. Change in plant communi-ty directly affected the community structure of grasshoppers. However , the diversity andevenness pattern of vegetations were not entirely parallel to those of grasshopper species.Diversity of plant species was significantly higher in moderately grazed plots ,while diversityof grasshopper species were significantly higher in ungrazed and lightly grazed plots. Calorificvalues of grasshoppers in subfamily Catantopinae were positively correlated with grass andnegatively correlated with forbe and short grasses , while the values of grasshoppers in sub-family Oedipodinae were negatively correlated with grasses and total plant biomass and posi-tively correlated with forbs and leguminous plant. In subfainily Gomphocerinae, some specieswere closely associated with overgrazed pastures, while some species were associated withgood floral conditions. Soil compactness and water content also singnificantly affectedgrasshopper species biomass and community complex. Grazing in moderate intensity pre-served the highest plant diversity and more diverse grasshopper community with lower pro-portion of the pest species. The relationships between grazing practice and conservation ofplant and grasshopper diversity were discussed.