Davidson Robert L, Rykken Jessica, Farrell Brian
Section of Invertebrate Zoology, Carnegie Museum of Natural History, 4400 Forbes Avenue, Pittsburgh PA 15213.
Zookeys. 2011(147):497-526. doi: 10.3897/zookeys.147.2111. Epub 2011 Nov 16.
As part of an All Taxa Biodiversity Inventory in Boston Harbor Islands national park area, an inventory of carabid beetles on 13 islands was conducted. Intensive sampling on ten of the islands, using an assortment of passive traps and limited hand collecting, resulted in the capture of 6,194 specimens, comprising 128 species. Among these species were seven new state records for Massachusetts (Acupalpus nanellus,Amara aulica,Amara bifrons, Apenes lucidulus, Bradycellus tantillus, Harpalus rubripes and Laemostenus terricola terricola-the last also a new country record; in passing we report also new state records for Harpalus rubripes from New York and Pennsylvania, Amara ovata from Pennsylvania, and the first mainland New York records for Asaphidion curtum). For most islands, there was a clear relationship between species richness and island area. Two islands, however, Calf and Grape, had far more species than their relatively small size would predict. Freshwater marshes on these islands, along with a suite of hygrophilous species, suggested that habitat diversity plays an important role in island species richness. Introduced species (18) comprised 14.0% of the total observed species richness, compared to 5.5% (17 out of 306 species) documented for Rhode Island. We surmise that the higher proportion of introduced species on the islands is, in part, due to a higher proportion of disturbed and open habitats as well as high rates of human traffic. We predict that more active sampling in specialized habitats would bring the total carabid fauna of the Boston Harbor Islands closer to that of Rhode Island or eastern Massachusetts in richness and composition; however, isolation, human disturbance and traffic, and limited habitat diversity all contribute to reducing the species pool on the islands relative to that on the mainland.
作为波士顿港岛国家公园地区全分类生物多样性清查的一部分，对13个岛屿上的步甲科甲虫进行了清查。在其中10个岛屿上进行了密集采样，使用了各种被动诱捕器并辅以有限的手工采集，共捕获了6194个标本，分属于128个物种。这些物种中有7个是马萨诸塞州的新记录种（微小尖跗步甲、奥氏阿玛步甲、双额阿玛步甲、亮黑阿步甲、坦氏步甲、红胫婪步甲和土栖地甲步甲——最后一种也是新的国家记录种；顺便提一下，我们还报告了红胫婪步甲在纽约和宾夕法尼亚的新记录，卵形阿玛步甲在宾夕法尼亚的新记录，以及弯翅隐步甲在纽约大陆的首次记录）。对于大多数岛屿而言，物种丰富度与岛屿面积之间存在明显的关系。然而，小牛岛和葡萄岛这两个岛屿的物种数量远远超过了根据其相对较小的面积所预测的数量。这些岛屿上的淡水沼泽，以及一系列喜湿物种，表明栖息地多样性在岛屿物种丰富度中起着重要作用。外来物种（18种）占观察到的物种总丰富度的14.0%，相比之下，罗德岛记录的外来物种占比为5.5%（306个物种中的17种）。我们推测，岛屿上外来物种比例较高，部分原因是受干扰和开阔栖息地的比例较高以及人类活动频繁。我们预测，在特殊栖息地进行更积极的采样，将使波士顿港岛的步甲科甲虫总群落的丰富度和组成更接近罗德岛或马萨诸塞州东部；然而，隔离、人类干扰和活动以及有限的栖息地多样性，都导致岛屿上的物种库相对于大陆有所减少。
