Hayford Barbara L, Caires Andrea M, Chandra Sudeep, Girdner Scott F
Department of Life Sciences, Wayne State College, Wayne, Nebraska, United States of America.
Biology Department, University of Nevada Reno, Reno, Nevada, United States of America.
PLoS One. 2015 Jan 16;10(1):e0117024. doi: 10.1371/journal.pone.0117024. eCollection 2015.
Relative to their scarcity, large, deep lakes support a large proportion of the world's freshwater species. This biodiversity is threatened by human development and is in need of conservation. Direct comparison of biodiversity is the basis of biological monitoring for conservation but is difficult to conduct between large, insular ecosystems. The objective of our study was to conduct such a comparison of benthic biodiversity between three of the world's largest lakes: Lake Tahoe, USA; Lake Hövsgöl, Mongolia; and Crater Lake, USA. We examined biodiversity of common benthic organism, the non-biting midges (Chironomidae) and determined lake trophic status using chironomid-based lake typology, tested whether community structure was similar between the three lakes despite geographic distance; and tested whether chironomid diversity would show significant variation within and between lakes. Typology analysis indicated that Lake Hövsgöl was ultra-oligotrophic, Crater Lake was oligotrophic, and Lake Tahoe was borderline oligotrophic/mesotrophic. These results were similar to traditional pelagic measures of lake trophic status for Lake Hövsgöl and Crater Lake but differed for Lake Tahoe, which has been designated as ultra-oligotrophic by traditional pelagic measures such as transparency found in the literature. Analysis of similarity showed that Lake Tahoe and Lake Hövsgöl chironomid communities were more similar to each other than either was to Crater Lake communities. Diversity varied between the three lakes and spatially within each lake. This research shows that chironomid communities from these large lakes were sensitive to trophic conditions. Chironomid communities were similar between the deep environments of Lake Hövsgöl and Lake Tahoe, indicating that chironomid communities from these lakes may be useful in comparing trophic state changes in large lakes. Spatial variation in Lake Tahoe's diversity is indicative of differential response of chironomid communities to nutrient enrichment which may be an indication of changes in trophic state within and across habitats.
相对于其稀缺性而言，大型深水湖泊拥有世界上很大一部分淡水物种。这种生物多样性正受到人类发展的威胁，亟需保护。生物多样性的直接比较是保护生物监测的基础，但在大型岛屿生态系统之间很难进行。我们研究的目的是对世界上最大的三个湖泊进行底栖生物多样性比较：美国的太浩湖、蒙古的库苏古尔湖和美国的火山口湖。我们研究了常见底栖生物——非吸血摇蚊（摇蚊科）的生物多样性，并使用基于摇蚊的湖泊分类法确定湖泊营养状态，测试了尽管地理距离遥远，这三个湖泊的群落结构是否相似；并测试了摇蚊多样性在湖泊内部和湖泊之间是否会显示出显著差异。分类分析表明，库苏古尔湖是超贫营养湖，火山口湖是贫营养湖，太浩湖是贫营养/中营养边界湖。这些结果与库苏古尔湖和火山口湖传统的浮游生物营养状态测量结果相似，但太浩湖的情况不同，根据文献中透明度等传统浮游生物测量方法，太浩湖被指定为超贫营养湖。相似性分析表明，太浩湖和库苏古尔湖的摇蚊群落彼此之间比它们与火山口湖群落更相似。三个湖泊之间以及每个湖泊内部的多样性各不相同。这项研究表明，这些大型湖泊的摇蚊群落对营养条件敏感。库苏古尔湖和太浩湖的深层环境中的摇蚊群落相似，这表明来自这些湖泊的摇蚊群落可能有助于比较大型湖泊的营养状态变化。太浩湖多样性的空间变化表明摇蚊群落对营养物质富集的不同反应，这可能表明不同栖息地内部和之间的营养状态发生了变化。
