Grazing significantly affects the distribution,growth,and productivity of shrubs.In this study,we evalu-ated the effects of grazing disturbance on the spatial distri-bution patterns and interspecific relationships of ...Grazing significantly affects the distribution,growth,and productivity of shrubs.In this study,we evalu-ated the effects of grazing disturbance on the spatial distri-bution patterns and interspecific relationships of two desert shrubs,Ammopiptanthus mongolicus and Sarcozygium xan-thoxylon.Three types of grazing conditions were considered,including enclosed area(EA),seasonal rotational grazing area(SRGA),and grazing area(GA)(100 m×100 m),in the West Ordos Nature Reserve of Inner Mongolia,China.The results showed that A.mongolicus and S.xanthoxylon populations were uniformly distributed at a small scale,and the distribution in EA and SRGA became gradually ran-dom.In GA,A.mongolicus population showed aggregated distribution but S.xanthoxylon population showed random distribution at a small scale. Moreover, both A. mongolicus and S. xanthoxylon populations at the 5-7 m scale showed random distribution. At the small and intermediate scales, the two species showed positive interspecific relationships of GA. However, no interspecific relationship was noted between the two species in EA and SRGA. A significant positive relationship (P < 0.01) was noted between the two species at 2-9 m and a negative relationship (P < 0.01) at 13-17 m scales in GA. Positive relationship (P < 0.01) was noted between the two species at 6-13 m scales and a sig-nificant negative relationship (P < 0.01) at 14-24 m scales in SRGA. The two species of desert shrubs showed posi-tive interspecific relationships at the small scale, and they showed negative relationships as the interspecific compe-tition intensified in the presence of grazing disturbance. When the grazing intensity exceeds a certain threshold, the interspecific relationships become weak. Therefore, moder-ate grazing would facilitate interspecific competition and species succession, whereas excessive grazing would disrupt natural competition causing desertification ultimately.展开更多
基金The work was supported by the Basic Scientific Research Foundation Special Project of the China Institute of Water Resources and Hydropower Research(nos.MK2020J08 and MK2016J03)National Natural Science Foundation of China:Action Mechanism Research on Ecological Spatial Configuration of Desert Shrub To The Formation and Development of Fertile Island(41967009).
文摘Grazing significantly affects the distribution,growth,and productivity of shrubs.In this study,we evalu-ated the effects of grazing disturbance on the spatial distri-bution patterns and interspecific relationships of two desert shrubs,Ammopiptanthus mongolicus and Sarcozygium xan-thoxylon.Three types of grazing conditions were considered,including enclosed area(EA),seasonal rotational grazing area(SRGA),and grazing area(GA)(100 m×100 m),in the West Ordos Nature Reserve of Inner Mongolia,China.The results showed that A.mongolicus and S.xanthoxylon populations were uniformly distributed at a small scale,and the distribution in EA and SRGA became gradually ran-dom.In GA,A.mongolicus population showed aggregated distribution but S.xanthoxylon population showed random distribution at a small scale. Moreover, both A. mongolicus and S. xanthoxylon populations at the 5-7 m scale showed random distribution. At the small and intermediate scales, the two species showed positive interspecific relationships of GA. However, no interspecific relationship was noted between the two species in EA and SRGA. A significant positive relationship (P < 0.01) was noted between the two species at 2-9 m and a negative relationship (P < 0.01) at 13-17 m scales in GA. Positive relationship (P < 0.01) was noted between the two species at 6-13 m scales and a sig-nificant negative relationship (P < 0.01) at 14-24 m scales in SRGA. The two species of desert shrubs showed posi-tive interspecific relationships at the small scale, and they showed negative relationships as the interspecific compe-tition intensified in the presence of grazing disturbance. When the grazing intensity exceeds a certain threshold, the interspecific relationships become weak. Therefore, moder-ate grazing would facilitate interspecific competition and species succession, whereas excessive grazing would disrupt natural competition causing desertification ultimately.
