岷江干旱河谷主要灌木种群生态位研究

利用Levins生态位宽度指数和Schoener生态位重叠指数分析了岷江干旱河谷20种主要灌木种群在土壤水分、全N、速效P、速效K和pH 5个资源维上的生态位宽度和生态位重叠特征.结果表明:小花滇紫草、三花莸、白刺花、多花胡枝子、马鞍羊蹄甲具有较大生态位宽度，对环境有较强的适应能力，在维持岷江干旱河谷群落的物种多样性和相对稳定性中发挥重要作用；种群在各个资源维上的宽度值不同，说明对不同的资源利用能力不尽相同，在不同资源空间中的生态适应性亦不同.各个资源维上所有种群生态位宽度和的大小依次为pH全N土壤水分速效K速效P.由此看出，物种对速效P和速效K的利用能力低于对土壤水分的利用；同属种群间的重叠值较低.具有较高生态位宽度的物种一般具有较高的生态位重叠，但并非生态位宽度小的物种其重叠值也就小.灌木种群生态位的研究可用于指导岷江干旱河谷植被的保护和恢复. 

Niche characteristics of main shrub populations in the arid valley of the Minjiang River, southwestern China

The arid valley of the Minjiang River located in southwestern China is an ecological fragile transition zone from the Tibetan Plateau to Sichuan Basin.This paper reported a field study on characteristics of shrub populations niche in the area to provide a scientific base for vegetation restoration and management. Niche breadths and overlaps of 20 main shrub populations along gradients of soil moisture,soil pH,available K,available P and total N were analyzed using Levins and Schoener indices. Onosma farrerii, Caryopteris terniflora,Sorphora vicifolia,Lespedeza floribunda and Bauhinia faberi had higher niche breadth and adaptability to environment and played a vital role in maintaining the diversity and stability of plant community; each population had different niche breadth in different resource dimensions.It showed that different populations had different ability of using resources and they had different ecological adaptability. The sum of niche breadth of all populations in different resource dimensions was as the following: soil pH > total N >soil moisture> available K > available P. It indicated that the ability of populations using available K and available P was lower than that of soil moisture, populations with high niche breadth also had high niche overlap, but not all species with low niche breadth had low niche overlap.