Ecological Characteristics of Sabina saltuaria Population at the Timberline Ectone on the Sunny Slope of the Sejila Mountain
Sabina saltuaria is an endemic timberline tree in the Qinghai-Tibetan Plateau, China. It is mainly distributed in the elevations between 4 320 m and 4 520 m on the sunny slope of the Sejila Mountain.One 0.8 hm~2 sample plot was established at the timberline >4 320 m on the sunny slope of the Mountain.Parameters, such as tree height,DBH,or diameter at base for seedlings and saplings, and location of each individual were recorded.The timberline features, population structure,dynamic and the time sequence prediction were investigated.The results showed that:(1)the upper elevation limit of the closed forests was found to be 4 320 m;the timberline elevations was 4 520 m on the sunny side with a gradualtype;(2) for the diameter class structure of the populations, most individuals were from Ⅰto Ⅳ, the number decreased sharply with the increase of diameter class, the survival curves were between Deevey type Ⅰ and Ⅱ, with an approximately stalbe trend;the variation trends of mortality rate (q_x) and hazard rate (k_x) were similar;(3)the analysis by time sequence model demonstrated that the individuals of the older age class would be increasing, indicating that S. saltuaria grew well before reaching the age class Ⅳ, and could adapt the timberline habitat conditions;but after Ⅳ,population self-thinning appeared because of the fiercer competition.It resulted from the biological characteristic of S. saltuaria, environment,as well as an adaptation strategy in ecological restoration of the high-altitude ecosystem.
国家科技期刊平台
NSTL
万方数据
维普
