甘肃臭草型退化草地优势物种格局控制关系

Pattern-controlling relationships of dominant species in degraded grassland of Melica przewalskyi

在石羊河上游高寒退化草地,应用点格局和RipleyK函数检测种间格局控制关系,按照时间序列设置甘肃臭草退化的5个样地,包括未形成斑块(CK)、斑块形成(A),斑块扩散(B)、斑块稳定(C)和斑块衰退(D)样地,研究了不同样地中甘肃臭草与阿尔泰针茅之间的空间分布格局、空间关联性和格局控制关系。结果表明:CK→D样地阿尔泰针茅由随机分布转变为聚集分布;甘肃臭草和阿尔泰针茅之间的关联性由显著负关联向无显著关联转变,负关联显著性先增强后减弱;A、B、C样地中分别在0～15、0～12和0～10cm尺度范围内甘肃臭草对阿尔泰针茅表现出格局控制关系,CK和D样地中没有格局控制关系。体型、规模大,竞争力强的物种,通过改变微生境,迫使其他物种改变分布方式,形成规则分布,进而形成对其他物种的格局控制作用。

In this paper, the methods of spatial point pattern and Ripley＇ s K function were adopted to study the spatial distribution, spatial association, and pattern-controlling relationships between Melica przewcdskyi and Stipa krylovii in degraded alpine grassland in the upper reaches of Shiyang River, western China, aimed to detect the interspecific pattern-controlling relationships of dominant species during retrogressive succession. Five sampling plots were installed according to the time series, i. e. , patch not formed （CK） , patch formed （A） , patch spread （B） , patch stable （C） , and patch degraded （D）. During the process of retrogressive succession （from CK to D） , the spatial distribution pattern of S. krylovii transferred from random to aggregative, and the association between M. przewalskyi and S. krylovii transferred from significant negative to not significant, with the significance decreased after an initial increase. In plots A, B, and C, M. przewalskyi showed pattern-controlling relationships to S. krylovii at 0-15, 0-12, and 0-10 cm scales, but the pattern-controlling relationships did not appear at plots CK and D. By altering microhabitats, the species with bigger size, larger scale, and stronger competition capability forced other species changed their distribution pattern and presented regular distribution, and thus, formed pattern-controlling relationships to other species.