Litter fauna and decomposition experiment in coastal ecosystems of Sapelo Island

In a field study (2007-2009) on Sapelo Island, GA, USA (31°27' N, 81°15' W), we incubated two contrasting detritus types in three distinct habitat types in coastal Georgia to test the hypotheses that (1) the litter fauna composition depends on the habitat and the litter type available; and (2) litter mass loss (as a proxy for decomposition) depends on environmental conditions (habitat) and the litter type. Litter of oak (Quercus virginiana) and pine (Pinus palustris) was collected in mesh baskets placed below trees; this prevented shed leaves from falling onto the ground, and thereby limited decomposition prior to our study. Litter was returned to the laboratory and air-dried for >7 days at room temperature. Each litter type was weighed (4.00 + 0.01 g dry weight) separately into mesh bags. Bags were placed in groups of four (N = 2 litter types x 2 mesh sizes) with six replicates per habitat (saltmarsh, forest, creek bank) and sampling date, and embedded in the existing litter present at the site. Litter bags were deployed in August 2007 and removed from the field after 1 month (September 2007), 6 months (February 2008), 12 months (August 2008), and 25 months (September 2009). Litter bags were individually stored in plastic bags for transport to the laboratory, where fauna were extracted in a Berlese apparatus, and the remaining litter cleaned of soil particles, dried at 60°C for 72 hours, and weighed. Invertebrates extracted from the mesh bags were identified to the highest taxonomic level possible and assigned to one of three functional groups: detritivores, predators or

在美国佐治亚州（GA）萨佩洛岛（Sapelo Island，北纬31°27′，西经81°15′）开展的一项野外研究（2007-2009年）中，我们在佐治亚州沿海的三种不同栖息地类型中培养两种对比性碎屑类型，以验证以下假设：（1）凋落物动物群组成依赖于栖息地及可用的凋落物类型；（2）凋落物质量损失（作为分解的代理指标）依赖于环境条件（栖息地）和凋落物类型。橡木（Quercus virginiana）和松树（Pinus palustris）的凋落物通过放置于树下的网篮收集；此举可防止落叶掉至地面，从而限制研究前的分解作用。凋落物被带回实验室，在室温下风干超过7天。每种凋落物类型分别称重（干重4.00±0.01 g）后装入网袋。网袋以每组四个的形式放置（N=2种凋落物类型×2种网眼大小），每个栖息地（盐沼、森林、河岸）及采样日期设六个重复，并埋入研究现场现有的凋落物中。网袋于2007年8月部署，分别在1个月（2007年9月）、6个月（2008年2月）、12个月（2008年8月）及25个月（2009年9月）后从野外取回。每个网袋单独装入塑料袋运输至实验室，在实验室中通过伯勒斯装置（Berlese apparatus）提取动物群，剩余凋落物清除土壤颗粒后，于60℃下干燥72小时并称重。从网袋中提取的无脊椎动物被鉴定至尽可能高的分类水平，并被归入三个功能群之一：碎屑食性动物、捕食者或