Plant community structure responds strongly to anthropogenic disturbances, which greatly influence community stability. The changes in community structure, aboveground biomass（AGB）, biodiversity and community stabil...Plant community structure responds strongly to anthropogenic disturbances, which greatly influence community stability. The changes in community structure, aboveground biomass（AGB）, biodiversity and community stability associated with different management practices were studied with a three-year field investigation in a temperate steppe of Inner Mongolia, China. The species richness, Shannon-Wiener index, evenness, plant functional type abundance, AGB, temporal community stability, summed covariance, scaling coefficient and dominant species stability were compared among areas subjected to long-term reservation（R）, long-term grazing（G）, mowing since enclosure in 2008（M） and grazing enclosure since 2008（E）. Site R had higher perennial grass abundance and lower species richness than sites G, M and E, although the AGB was not significantly different among the four sites. The species structure varied from a single dominant species at site R to multiple dominant species at sites G, M and E. The long-term reservation grassland had lower biodiversity but higher stability, whereas the enclosed grassland with/without mowing had higher biodiversity but lower stability. Different stability mechanisms, such as the compensatory dynamics, mean-variance scaling and dominant species stability were examined. Results showed that community stability was most closely related to the relative stability of the dominant species, which supports the biomass ratio hypothesis proposed by Grime.展开更多
The arid and semi-arid northwestern China has been undergoing ecological degradation and the efforts to reverse the ecological degradation have been undertaken for many years. Some shifting dunes have been fixed and t...The arid and semi-arid northwestern China has been undergoing ecological degradation and the efforts to reverse the ecological degradation have been undertaken for many years. Some shifting dunes have been fixed and the vegetation has been partially recovered in certain areas and the Mu Us Sandy Land in the Ordos Plateau is an example of the success. The present study attempts to reveal the relationships between the vegetation restoration and ecohydrology in the Mu Us Sandy Land. We continuously measured soil water content at 10-min intervals under three vegetation types （i.e., shifting dune, shrub-dominated community, and herb-dominated community） in the Mu Us Sandy Land from April 2012 to October 2013. The results show the infiltration coefficient increased with increased rainfall amount and eventually reached a stable value. Infiltration coefficients were 0.91, 0.64, and 0.74 in the shifting dune, in the shrub-dominated community, and in the herb-dominated community, respectively. Cumulative infiltration and soil texture are two vital factors affecting the depths of rainfall penetration. Only rainfall events larger than 35.0 mm could recharge soil water at the 60-80 cm layer in the herb-dominated community. Our results imply that the expected forward succession of restored vegetation may be destined to deterioration after reaching the climax simply because of following two facts： （1） soil water is mainly retained at shallower layer and （2） plant fine roots mainly distribute in deeper layer in the herb-dominated community.展开更多
Rainfall interception is of great significance to the fully utilization of rainfall in water limited areas.Until now,studies on rainfall partitioning process of typical ecosystems in Heihe River Basin,one of the most ...Rainfall interception is of great significance to the fully utilization of rainfall in water limited areas.Until now,studies on rainfall partitioning process of typical ecosystems in Heihe River Basin,one of the most important inland river basins in China,is still insufficient.In this study,six typical ecosystems were selected,namely alpine meadow,coniferous forest,mountain steppe,desert,cultivated crop,and riparian forest,in Heihe River Basin for investigation of the rainfall interception characteristics and their influencing factors,including rainfall amount,duration,and intensity,based on the gross rainfall and high temporal resolution soil moisture data obtained from 12 automatic observation sites.The results show that the average interception amount and average interception rate of the six ecosystems are significantly different: alpine meadow 6.2 mm and 45.9%,coniferous forest 7.4 mm and 69.1%,mountain steppe 3.5 mm and 37.3%,desert 3.5 mm and 57.2%,cultivated crop 4.5 mm and 69.1%,and riparian forest 2.6 mm and 66.7%,respectively.The rainfall amount,duration,and intensity all had impact on the process of rainfall interception.Among these three factors,the impact of rainfall amount was most significant.The responses of these ecosystems to the rainfall characteristics were also different.Analyzing rainfall interception with high temporal resolution soil moisture data is proved to be a feasible method and need further development in the future.展开更多
基金funded by the National Natural Science Foundation of China (41030535, 41371069)the Fundamental Research Funds for the Central Universitiesthe Program for Changjiang Scholars and Innovative Research Team in University (IRT1108)
文摘Plant community structure responds strongly to anthropogenic disturbances, which greatly influence community stability. The changes in community structure, aboveground biomass（AGB）, biodiversity and community stability associated with different management practices were studied with a three-year field investigation in a temperate steppe of Inner Mongolia, China. The species richness, Shannon-Wiener index, evenness, plant functional type abundance, AGB, temporal community stability, summed covariance, scaling coefficient and dominant species stability were compared among areas subjected to long-term reservation（R）, long-term grazing（G）, mowing since enclosure in 2008（M） and grazing enclosure since 2008（E）. Site R had higher perennial grass abundance and lower species richness than sites G, M and E, although the AGB was not significantly different among the four sites. The species structure varied from a single dominant species at site R to multiple dominant species at sites G, M and E. The long-term reservation grassland had lower biodiversity but higher stability, whereas the enclosed grassland with/without mowing had higher biodiversity but lower stability. Different stability mechanisms, such as the compensatory dynamics, mean-variance scaling and dominant species stability were examined. Results showed that community stability was most closely related to the relative stability of the dominant species, which supports the biomass ratio hypothesis proposed by Grime.
基金supported by the National Natural Science Foundation of China(41130640,41321001,31470402)the Program for Changjiang Scholars and Innovative Research Team in University(IRT1108)the Fundamental Research Funds for the Central Universities(2012CXQT07)
文摘The arid and semi-arid northwestern China has been undergoing ecological degradation and the efforts to reverse the ecological degradation have been undertaken for many years. Some shifting dunes have been fixed and the vegetation has been partially recovered in certain areas and the Mu Us Sandy Land in the Ordos Plateau is an example of the success. The present study attempts to reveal the relationships between the vegetation restoration and ecohydrology in the Mu Us Sandy Land. We continuously measured soil water content at 10-min intervals under three vegetation types （i.e., shifting dune, shrub-dominated community, and herb-dominated community） in the Mu Us Sandy Land from April 2012 to October 2013. The results show the infiltration coefficient increased with increased rainfall amount and eventually reached a stable value. Infiltration coefficients were 0.91, 0.64, and 0.74 in the shifting dune, in the shrub-dominated community, and in the herb-dominated community, respectively. Cumulative infiltration and soil texture are two vital factors affecting the depths of rainfall penetration. Only rainfall events larger than 35.0 mm could recharge soil water at the 60-80 cm layer in the herb-dominated community. Our results imply that the expected forward succession of restored vegetation may be destined to deterioration after reaching the climax simply because of following two facts： （1） soil water is mainly retained at shallower layer and （2） plant fine roots mainly distribute in deeper layer in the herb-dominated community.
基金National Natural Science Foundation of China,No.91425301,No.91725000State Key Laboratory of Land Surface Processes and Resource Ecology,No.2017-ZY-04
文摘Rainfall interception is of great significance to the fully utilization of rainfall in water limited areas.Until now,studies on rainfall partitioning process of typical ecosystems in Heihe River Basin,one of the most important inland river basins in China,is still insufficient.In this study,six typical ecosystems were selected,namely alpine meadow,coniferous forest,mountain steppe,desert,cultivated crop,and riparian forest,in Heihe River Basin for investigation of the rainfall interception characteristics and their influencing factors,including rainfall amount,duration,and intensity,based on the gross rainfall and high temporal resolution soil moisture data obtained from 12 automatic observation sites.The results show that the average interception amount and average interception rate of the six ecosystems are significantly different: alpine meadow 6.2 mm and 45.9%,coniferous forest 7.4 mm and 69.1%,mountain steppe 3.5 mm and 37.3%,desert 3.5 mm and 57.2%,cultivated crop 4.5 mm and 69.1%,and riparian forest 2.6 mm and 66.7%,respectively.The rainfall amount,duration,and intensity all had impact on the process of rainfall interception.Among these three factors,the impact of rainfall amount was most significant.The responses of these ecosystems to the rainfall characteristics were also different.Analyzing rainfall interception with high temporal resolution soil moisture data is proved to be a feasible method and need further development in the future.
