No abstract

No abstract

Aims: Karst caves are a gathering place for biodiversity in belowground extreme environments, but little is known about their food web structure. We investigated this by assessing the food sources and trophic levels of terrestrial cave fauna in Yuping Town, Libo County, Guizhou Province. We further documented cave biodiversity resource utilization to provide important reference data to inform conservation of karst ecosystems. Methods: We investigated terrestrial cave animals in three representative caves in Yuping Town, Libo County, Guizhou Province in October 2016. In each cave system, we recorded δ 13 C and δ 15 N values of terrestrial cave animals and assessed variation in these characteristics. We then assessed the basic carbon source by analyzing the stable isotopes δ 13 C and δ 15 N. We then estimated the contribution rates of five types of basic carbon sources to terrestrial consumers using IsoSource software, and explored the trophic level of each faunal species in each cave. Results: The δ 13 C value of cave plants ranged from -38.25‰ ± 0.95‰ to -29.44‰ ± 0.49‰, while that of soil organic matter ranged from -32.73‰ ± 0.03‰ to -24.68‰ ± 0.41‰. Most of these values were outside the change interval of δ 13 C in cave plants. The δ 13 C and δ 15 N values of cave fauna ranged from -34.22‰ ± 0.39‰ to -14.83‰ ± 0.78‰ and from 1.86‰ ± 0.20‰ to 16.43‰ ± 0.05‰, respectively, suggesting large differences among species and groups. The •研究报告• 徐承香等: 贵州荔波玉屏洞穴陆生动物食物来源及营养级 1109 https://www.biodiversity-science.net 研究报告 78.3% contribution rate of soil organic matter to cave fauna was higher than that of the primary productivity of plants. The trophic level of cave consumers in Yuping Town, Libo County ranged from 1.01 to 5.32. Megascolecidae, snails, Oniscidae, horseshoes, Tipulidae, and Noctuidae were mainly classified as primary consumers into the second trophic level; Scutigeridae, Myrmeleontidae (larvae), and bats were classified into the third trophic level; Blattidae were classified into the second to third trophic level; Rhaphidophoridae and Labiduridae were classified into the second to fourth trophic level; and spiders spanned three trophic levels, being classified into the second to fifth trophic level. Conclusions: Organic matter in cave soil is the main food source for cave consumers. Most cave fauna in the same taxonomic group had a consistent trophic level in caves, though some fauna belonging to the same taxa had different trophic levels in different caves or in different light zones of the same cave.

Eight heavy metals content in the dominant animal groups, soil and water in Malang and Dashui caves were examined. The results showed that zinc contents in Porcellio scaber from Dashui and Malang caves were 448.80 and 598.00 mg/kg, respectively, which is the highest among all these 8 metals, while Pb was not detected in Diestrammena marmorata and Rhinolophidae pearsoni, suggesting that both animals were incapable of or poor in Pb accumulation. The highest average value of enrichment coefficient for soil-born Cd in animals from Dashui cave was 4.15, while that for water-born Zn was 91723.84. By contrast, the highest average value of enrichment coefficient for soil-born Cd in animals from Malang cave was 8.48, and that for water-born Zn was 708102.64.

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 inthe whole cave and at especially severe level of ecological risk (Eri=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