Vol. 46 No. 5, 2007
Leaf Breakdown in a Subtropical Stream Riffle and Its Association with Macroinvertebrates
Sen-Her Shieh1, Chorng-Bin Hsu2, Chiao-Ping Wang3, and Ping-Shih Yang4,*
1Department of Ecology, Providence University, 200 Chung-Chi Rd., Shalu, Taichung 433, Taiwan
2Research Center for Biodiversity, Academia Sinica, 128 Academia Rd., Sec. 2, Taipei 115, Taiwan
3Fushan Research Center, Taiwan Forestry Research Institute, Ilan 260, Taiwan
4Department of Entomology, National Taiwan University, 1 Roosevelt Rd., Sec.4, Taipei 106, Taiwan
Sen-Her Shieh, Chorng-Bin Hsu, Chiao-Ping Wang, and Ping-Shih Yang (2007) The relationships between the quality of leaves of 3 trees (Machilus thunbergii, Schefflera octophylla, and Ficus erecta)
and the assemblages of macroinvertebrates were studied at a riffle
section of a 3rd-order subtropical forest stream in northern Taiwan.
Macroinvertebrate taxon richness and density that colonized bags of
leaves of the 3 tree species did not significantly differ.
Macroinvertebrate assemblages were dominated by collectors, such as
non-Tanypondinae Chironomidae, Prosimulium spp., and Baetis
spp., which constituted > 79% of the total fauna. Results of a
principal component analysis (PCA) showed that the macroinvertebrate
assemblages were associated with the incubation time of the litter bags
in the stream and the fine particulate organic matter (FPOM) trapped by
the leaf bags, but not with the variables of leaf litter quality.
Shredders, predominantly small nemourids, accounted for only 5.7%, 7.1%
and 10.8% of the total macroinvertebrate assemblages on M. thunbergii, S. octophylla, and F. erecta,
respectively, suggesting that macroinvertebrates played only a minor
role in leaf litter breakdown in this subtropical 3rd-order stream.
However, the density of shredders on F. erecta, as a function of the weight of the leaf litter remaining, was significantly higher than that of M. thunbergii,
possibly because of the preference of shredders for high-quality food
resources. In a comparison with the temperate zone systems, the
dominant taxa of shredders that colonized the leaf litter were similar,
but their relative abundances were much less in this subtropical forest
Key words: Leaf litter quality, Shredders, Collectors, Particulate organic matter (POM), Taiwan.
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