重庆中梁山不同石漠化生境中石生南亚毛灰藓斑块的空间分布格局

基于重庆市中梁山喀斯特(Karst)地区3种不同石漠化生境(潜在石漠化、轻度石漠化和中度石漠化)中0.75 hm2样地的数据,以石生南亚毛灰藓(Homomallium simlaense)的3种斑块(小斑块、中斑块和大斑块)为研究对象,运用点格局O-ring的单变量和双变量统计方法对斑块空间格局以及斑块间的关联性进行生态学特性与形成过程分析,取得以下结果。(1)南亚毛灰藓总斑块数量关系为轻度石漠化潜在石漠化中度石漠化;在3种石漠化生境中,各种类型的斑块均呈现出小斑块中斑块大斑块的数量变化。(2)小斑块和中斑块在小尺度上主要为聚集分布,其它尺度上为随机分布;大斑块在整个尺度上都呈随机分布。(3)中斑块与小斑块在3种生境中均在小尺度上有显著的关联性;大斑块与中斑块仅在潜在石漠化生境中的小尺度上有关联性,其它斑块间在不同生境与尺度上均无关联性。(4)环境因子中坡度和石缝数对斑块的分布起很大作用,但是相对湿度是影响分布的主要因子。(5)在相对湿度和郁闭度胁迫方面,小斑块和中斑块随环境胁迫增大而趋于聚集分布。研究结果表明,苔藓斑块大小及其分布式样在石漠化地区裸露岩石的生态恢复中具有重要指示意义。

Spatial Distribution Pattern of Epilithic Moss Homomallium simlaense Patches in Rocky Desertification Habitats in Zhongliang Mountain,Chongqing, Southwest China

The present study used O-ring Point Pattern Analysis to analyze the spatial distribution patterns of three sizes of moss patches in the Karst area of Zhongliang Mountain, Chongqing, to understand the ecological characteristics and process of the common epilithic moss species Homomallium simlaense. Data were from 0.75 hm² sample plots in three rocky desertification habitats (potential, slight, and medium rocky desertification). The total number of H. simlaense patches was higher in slight rocky desertification plots, then potential rock desertification plots; medium rock desertification plots had lower patch number. In the three habitats, the changes in patch number were from small patches>medium patches>large patches. Small and medium patches were significantly clustered at small scales but randomly distributed at other scales; however, the large patches randomly distributed at all scales. We found a positive correlation between medium and small patches at small scales in the three habitats and no significant correlation between large and medium patches at most scales, except small scales in potential rocky desertification plots. Relative humidity was the most important environmental factor affecting the moss patch distribution, and the slope and number of rock fracture also played a significant role. Small and medium patches tended to aggregate with increasing moisture and shade stress. Moss patch size and its distribution pattern are good predictors of the ecological restoration in Karst rocky desertification areas.