Trampling, litter removal, and variations in the composition and relative abundance of soil arthropods in a subtropical hardwood forest

Ya-Fu Lee, Yen-Min Kuo, Sheng-Shan Lu, Duen-Yuh Chen, Hao-Jiang Jean, and Jung-Tai Chao (2009) Trampling, litter removal, and variations in the composition and relative abundance of soil arthropods in a subtropical hardwood forest. Zoological Studies 48(2): 162-173. Relationships of human trampling and litter removal with physicochemical properties and arthropod diversity of forest soils were studied in a secondary hardwood forest in northern Taiwan. In 4 sampling sessions, 360 soil cores were extracted from 24 randomly chosen replicate plots, representing soil samples from (1) densely vegetated areas, (2) bare trails as a result of non-mechanical trampling, and (3) ground underneath nylon-mesh litter traps set up on trails. We collected 7 classes and at least 17 orders of arthropods, with an estimated mean density of 13,982 ind./m2. The Collembola and Acari were the most common groups. The former dominated in abundance, comprising 8 families (2.5 ± 0.1 ore), followed by the Acari (e.g., oribatids) with at least 37 families (2.2 ± 0.1 per core). The density and number of taxa of arthropod overall, as well as the density and number of families of springtails and oribatids in particular, were highest in soil samples from vegetated areas. Soil samples beneath litter traps were in between, whereas the lowest taxon numbers and densities consistently occurred in soils from bare trails. These patterns were correlated with a trend of significantly more-compacted soils on bare trails than on trails beneath litter traps and an even greater difference when compared to soils of vegetated areas. While the moisture content and temperature of soils tended to vary in response to local weather conditions, soil samples in vegetated areas contained higher carbon and nitrogen contents and slightly lower pH values than those from bare trails. Trampling and litter removal did not affect the frequency of occurrence of the major taxa; yet dramatic declines occurred in relative abundances of the predominant collembolans and Acari, from over 20% to about 90%. At the family level, however, trampling and litter removal appeared to cause larger changes in the composition of the Acari than in collembolans. http://zoolstud.sinica.edu. tw/Journals/48.2/162.pdf.