Elkins Ned Z, Whitford Walter G
Department of Biology, New Mexico State University, 88003, Las Cruces, New Mexico, USA.
Oecologia. 1982 Dec;55(3):303-310. doi: 10.1007/BF00376916.
We sampled the soil microarthropod community monthly in the oak-mesquite sand hill ecosystem. Small fungiphagous prostigmated mites (pyemotids, lordalychids and tarsonemids) that dominated the soil fauna in winter were replaced by large predaceous mites (rhodacarids and laelapids) in summer and autumn.We compared organic matter loss and microarthropod and nematode populations in shinnery oak (Quercus harvardii) using insecticide and untreated litter in fiberglass litterbags.Microarthropods extracted from litterbags showed a seasonal pattern similar to the soil cores except that collembolans and psocopterans were abundant in the litter and not in the soil cores. Numbers of free living nematodes were consistently greater than from untreated litter. The ratio of non-stylet to stylet bearing nematodes extracted from litter decreased from 4:1 in one month bags to 0.8:1.0 in the one year bags. Laboratory experiments showed that rhodacarid mites fed voraciously on nematodes.Untreated litter exhibited higher rates of organic matter loss than the insecticide treated litter; 20% and 35% respectively.We suggest that the abundant mesostigmatid mites prey on free living nematodes and that eliminating the predators allows the nematodes to overgraze the fungi and bacteria. The soil modifies the microclimate in buried litter allowing for higher biological activity, hence higher rates of decomposition.
我们每月在橡木-牧豆树沙丘生态系统中对土壤微型节肢动物群落进行采样。冬季主导土壤动物群落的小型食真菌前气门螨（蒲螨、洛氏螨和跗线螨）在夏季和秋季被大型捕食性螨（红螨和厉螨）所取代。我们使用装有杀虫剂和未处理凋落物的玻璃纤维凋落物袋，比较了矮栎（哈佛栎）中有机质损失以及微型节肢动物和线虫的数量。从凋落物袋中提取的微型节肢动物呈现出与土壤核心类似的季节性模式，只是弹尾虫和啮虫在凋落物中数量丰富，而在土壤核心中则不然。自由生活线虫的数量始终高于未处理的凋落物。从凋落物中提取的无口针线虫与有口针线虫的比例从一个月袋中的4:1降至一年袋中的0.8:1.0。实验室实验表明，红螨大量捕食线虫。未处理的凋落物比用杀虫剂处理的凋落物表现出更高的有机质损失率，分别为20%和35%。我们认为，丰富的中气门螨捕食自由生活的线虫，而消灭捕食者会使线虫过度啃食真菌和细菌。土壤改变了埋藏凋落物中的小气候，从而允许更高的生物活性，进而实现更高的分解速率。
