载畜率和生活型功能群对荒漠草原植物群落物种多样性的影响OA

Based on a long-term grazing experiment platform with a gradient of stocking rates[0、0.81、1.92、2.73 sheep/(hm2·a)],this study employed a single-factor randomized block design to investigate the response mechanisms of plant community species diversity to stocking rate and life form functional groups in the Stipa breviflora desert steppe of Inner Mongolia,and to elucidate the coupling relationship between multi-scale diversity dynamics and functional groups interaction.The results showed that:With increasing of stocking rate,α and γ diversity of plant communities decreased,whereas β diversity increased under light grazing.The shrub and semi-shrub functional group contributed the largest proportion of variance in commu-nity diversity at the α and γ scales(>60%),while the annual and biennial plants functional groups and the shrub and semi-shrub functional group played key roles in explaining variance the β scale(43.61%and 43.42%,respectively);The species diversity of the perennial grass functional group showed no significant response to stocking rate.Complementary diversity trends between perennial forbs and shrubs and semi-shrubs were observed,which may partially buffer the negative effects of grazing on community diversity.Meanwhile,the species diversity of annual and biennial plants was significantly negatively correlated with that of perennial forbs and shrubs and semi-shrubs(P<0.05).In conclusion,grazing regulates multi-scale diversity by altering species composition and interactions among functional groups.The tolerance of the shrub and semi-shrub functional group,coupled with the dynamic compensation of annual and biennial plant functional group,represents an important mechanism sustaining diversity in the desert steppe.The findings provide a theoretical basis for ecological restoration and sustainable management of degraded grasslands.