Structure and dynamics of herbaceous layer vegetation of artificial Caragana intermedia shrublands in desert steppe
Summary Caragana intermedia is a leguminous shrub plant , which is planted in desert steppe area on a large scale , which can also be used as forage grass , with very important ecological and economic value . However , a series of shrub and grass resource competition problem emerged with the aging of C . intermedia shrublands . The growth of zonal perennial vegetation often subjected to great constraints , and self‐degradation of C . intermedia shrublands was also developed to different degrees . The reasonable collocation relations of shrub and grass were one of the key elements to maintain ecology and production services of C . intermedia shrublands in desert steppe . The objective of this study is to understand composition characteristics of herbaceous plant species and its dynamic change rules around the C . intermedia shrublands , and to reveal the structure of shrub and grass and the evolution trend of C . intermedia shrubland system . Taking natural grassland as a control , spatiotemporal substitution methods were used , and a research sequence constituted of different ages of C . intermedia shrubland plots was erected to carry out tracking , monitoring and analysis of vegetation seasonal dynamics at interior and exterior of the shrubs . The results showed that : 1) The number of natural grassland (CK) and herbaceous plant species of C . intermedia shrublands were 25 species , belonging to 8 families and 23 genera . The highest species number was the 16 a C . intermedia shrublands ( 16 species) , and the number of species gradually decreased with aging of C . intermedia shrublands .Pennisetum centrasiaticum , Cleistogenes squarrosa and other perennial grasses began to appear , but the dominant species still was short‐lived annual plants . Species diversity indexes showed a decreasing trend after a steady increase with aging of C . intermedia shrublands . 2) The seasonal dynamics , coverage degree , aboveground biomass and species number of herbaceous layer vegetation were mainly affected by the change of precipitation and temperature , but the existence of C . intermedia shrubs delayed the grow th recovery rate of herbaceous layer vegetation after spring drought , and the highest relative volatility index was 25 a C . intermedia shrublands . 3) The coverage degree of herbaceous layer vegetation at the interior and exterior of the C . intermedia shrubs and the seasonal dynamics of aboveground biomass at the interior of the C . intermedia shrubs were significantly changed by the ages of C . intermedia shrubland , and a significant interaction between ages of C . intermedia shrublands and seasonal factors was observed . In conclusion , the structure and dynamics of herbaceous layer vegetation of C . intermedia shrublands in desert steppe is regulated by the ages of C . intermedia shrublands , season and spatial heterogeneity and so on . With the decay of C . intermedia shrublands , the community gradually grows towards zonal vegetation succession , but under the circumstance of short‐lived annual plants as dominant species , maintenance of system stability and succession direction still has many uncertainties .
desert steppeartificial Caragana intermedia shrublandsage of shrublandsseasonal dynamicsherbaceous layer vegetation
NETL
NSTL
万方数据
维普
