Perissinotto Renzo, Bird Matthew S, Bilton David T
DST/NRF Research Chair in Shallow Water Ecosystems, Nelson Mandela Metropolitan University, C/o Department of Zoology, P.O. Box 77000, Port Elizabeth, 6031, South Africa.
Marine Biology and Ecology Research Centre, School of Marine Science & Engineering, Plymouth University, Drake Circus, Plymouth PL4 8AA, United Kingdom.
Zookeys. 2016 Jun 2(595):85-135. doi: 10.3897/zookeys.595.8614. eCollection 2016.
Water beetles are one of the dominant macroinvertebrate groups in inland waters and are excellent ecological indicators, reflecting both the diversity and composition of the wider aquatic community. The predaceous water beetles (Hydradephaga) make up around one-third of known aquatic Coleoptera and, as predators, are a key group in the functioning of many aquatic habitats. Despite being relatively well-known taxonomically, ecological studies of these insects in tropical and subtropical systems remain rare. A dedicated survey of the hydradephagan beetles of the Lake St Lucia wetlands (South Africa) was undertaken between 2013 and 2015, providing the first biodiversity census for this important aquatic group in the iSimangaliso Wetland Park, a UNESCO World Heritage Site within the Maputaland biodiversity hotspot. A total of 32 sites covering the entire spectrum of waterbody types were sampled over the course of three collecting trips. The Lake St Lucia wetlands support at least 68 species of Hydradephaga, a very high level of diversity comparing favourably with other hotspots on the African continent and elsewhere in the world and a number of taxa are reported for South Africa for the first time. This beetle assemblage is dominated by relatively widespread Afrotropical taxa, with few locally endemic species, supporting earlier observations that hotspots of species richness and centres of endemism are not always coincident. Although there was no significant difference in the number of species supported by the various waterbody types sampled, sites with the highest species richness were mostly temporary depression wetlands. This contrasts markedly with the distribution of other taxa in the same system, such as molluscs and dragonflies, which are most diverse in permanent waters. Our study is the first to highlight the importance of temporary depression wetlands and emphasises the need to maintain a variety of wetland habitats for aquatic conservation in this biodiverse region.
水甲虫是内陆水域中占主导地位的大型无脊椎动物类群之一，是出色的生态指标，能反映更广泛水生群落的多样性和组成。捕食性水甲虫（沼甲亚目）约占已知水生鞘翅目的三分之一，作为捕食者，它们是许多水生生境功能中的关键类群。尽管在分类学上相对为人熟知，但对这些昆虫在热带和亚热带系统中的生态学研究仍然很少。2013年至2015年期间，对南非圣卢西亚湖湿地的沼甲亚目甲虫进行了专门调查，为伊西曼加利索湿地公园（马普托兰生物多样性热点地区内的一个联合国教科文组织世界遗产地）这一重要水生类群提供了首次生物多样性普查。在三次采集行程中，共对涵盖各种水体类型的32个地点进行了采样。圣卢西亚湖湿地至少有68种沼甲亚目甲虫，多样性水平非常高，与非洲大陆其他热点地区以及世界其他地方相比毫不逊色，并且有一些分类单元是南非首次报道。这个甲虫群落以分布相对广泛的 Afrotropical 分类单元为主，当地特有物种很少，这支持了早期的观察结果，即物种丰富度热点和特有中心并不总是重合的。尽管所采样的各种水体类型所支持的物种数量没有显著差异，但物种丰富度最高的地点大多是临时洼地湿地。这与同一系统中其他分类单元（如软体动物和蜻蜓）的分布形成了显著对比，它们在永久性水域中最为多样。我们的研究首次强调了临时洼地湿地的重要性，并强调在这个生物多样性地区为水生生物保护维持各种湿地生境的必要性。
