张家界大鲵繁殖洞穴外溪冬季大型无脊椎动物

摘要

The Chinese giant salamander (Andrias davidianus) is an endangered amphibian in China and the largest salamander in the world.A. davidianus is endemic to rocky, fast-running mountain streams and lakes in China. The wild population is decreasing because of over-hunting and loss of habitat. This endemic species is currently listed in Annex I of CITES and Class II of the Protected Animals in China. Previous studies have reported that this species is carnivorous, and the larvae prey mainly on small aquatic animals, such as shrimp and aquatic insects, whereas adults prey on fish, frogs, and crabs. Macroinvertebrates are important groups in stream and river eco-systems. As most macroinvertebrates have a stationary life mode or a limited migration distance, the species and their numbers are important to access the environmental quality of a habitat. Thus, macroinvertebrate data are commonly used as water quality bioindicators. Field investigations were conducted during January 2013 and 2014 in five natural breeding caves (seven sampling sites) located in the Hunan Zhangjiajie Chinese Giant Salamander State Reserve. The objective was to use macroinvertebrates to assess the health of theA. davidianus habitat. A total of 117 macroinvertebrate taxa were identified in five phyla, eight classes, 16 orders, and 59 families during January 2013. Of them, 107 were aquatic insects, three were mollusks, two were crustaceans, and one each was Hirudinea, Turbellaria, and Nematoda. A mean of 27 macroinvertebrate taxa were collected over the 2 years of sampling. The maximum and minimum numbers collected were 33 and 15 in the water outlet of Qiyanquan Cave (S6) and the water outlet of Luozita Cave (S1), respectively. The density of macroinvertebrates ranged from 872.2 to 3511.1 ind/m2 (average, 1747.6 ind/m2). Aquatic insects were the dominant group, and their relative abundance was 97.05%.Baetis sp.,Choroterpes sp.,Hydropsyche sp.,Serratella sp.,Heptagenia sp., andAntocha sp. were the most dominant taxa, and their relative abundances were 32.27%, 9.15%, 7.13%, 6.61%, 6.52%, and 5.45% of total density, respectively. The water quality bioassessment based on the Shannon-Wiener diversity and biotic in-dex(BI) showed that S1, the water outlet of Wumuyu Cave (S3), and S6 had very good water quality, and that S1 and the water outlet of Bamaoxi Cave (S7) were slightly polluted. The dominant functional feeding groups were collectors-gatherers and predators, and all sites except S1 showed aK-dominant macroinvertebrate curve. The macroinvertebrate population had been barely disturbed by humans compared with other sites. In conclusion, higher levels of macroinvertebrate biodiversity were found in most rivers near natural breeding caves during the larval outflow period in Zhangjiajie City, but food shortages were a risk for larvae in some rivers near natural breeding caves. These results suggest that the karst caves and macroinvertebrates should be protected.%2013年1月与2014年1月对湖南张家界大鲵国家级自然保护区大鲵自然繁殖洞穴外溪大型无脊椎动物群落和水质状况进行了调查。共采集到动物117种,隶属于5门8纲16目59科。其中水生昆虫107种,软体动物3种,甲壳动物2种,环节动物3种,涡虫纲和线虫动物各1种。两年各采样点物种数平均为27种,七眼泉洞穴出水口(S6)物种数最多,为33种,骡子塔洞穴出水口(S1)物种数最少为15种。2年1个月中各采样点大型无脊椎动物密度介于872.2~3511.1 ind/m2,平均密度为1747.6 ind/m2,水生昆虫为优势类群,相对丰度97.05%,其中,四节蜉(Baetis sp.)、宽基蜉(Choroterpes sp.)、纹石蛾(Hydropsyche sp.)、锯形蜉(Serratella sp.)、扁蜉(Heptagenia sp.)和朝大蚊(Antocha sp.)为最优势的种类,其丰度分别占总丰度的32.27%、9.15%、7.13%、6.61%、6.52%、5.45%；基于Shannon-Wiener指数和BI生物指数的水质评价结果显示,各洞穴出水口溪流中,乌木峪(S3)、院子(S4)和七眼泉(S6)水质最为清洁,骡子塔(S1)和芭茅溪(S7)水质稍差,有轻微污染；功能摄食类群分析结果显示各采样点以收集者(GC)和捕食者(PR)为主要优势类群； K－优势曲线结果表明,除了骡子塔洞穴出水口溪流(S1)受到较重的人为影响外,其他采样点基本保持了较高的物种多样性。从两年调查状况来看,张家界大鲵(Andrias davidianus)自然繁殖洞穴外溪出苗期大型无脊椎动物具有较高的多样性,环境敏感类群优势地位明显,通过估算稚鲵营养容纳量推测,洞穴外溪可为野生稚鲵提供良好的饵料条件,但一些自然繁殖洞穴外溪稚鲵食物可能存在不足的风险,应加强保护区内喀斯特溶洞与大型无脊椎动物群落的保护。