Abstract:

We investigated the community diversity of cave animals in different light zones of the Guizhou Zhijin Cave in August, 2011. We used principal components analysis (PCA) to examine the relationships between animal community diversity and environment factors. We assessed the potential ecological risk degree of heavy metals in the cave based on the Hakanson potential ecological risk index. We identified 1,080 specimens, which belong to three phyla, five classes, 26 families and 41 species or groups of species, which could be divided into five communities. The highest community diversity, richness index, evenness index, and dominance index were light zone of exit (2.7996), light zone of entrance (4.5399), light zone of exit (0.9196) and weak-light zone of exit (0.1868), respectively. Index of similarity between light zone of entrance and light zone of exit (0.6248) was highest. The richness and dominance indices of the communities were low, but community diversity and richness tended to decrease based on the order of the light intensity (i.e., light zone>weak-light zone>dark zone). Dominant species included Hemiphaedusa pluviatilis and H. moellendorffiana. Organic matter of soil, content of CO₂ in the air, cave humidity, cave temperature, and heavy metal contamination of soil were the dominant factors to affect animal community diversity in the cave. Although Cu, Zn, Ni, Cr, As in soils were at ecologically low levels, Hg pollution was relatively high in the whole cave and at especially severe level of ecological risk (E_rⁱ=256.000) in the light zone of cave entrance. As far as the average potential ecological risk level (RI=192.714) of six heavy metals were concerned, the cave was contaminated at a certain degree with heavy metals.

Key words: diversity of animal communities, environmental factors, ecological risk appraisal, principal components analysis, Zhijin Cave