Shredder colonization and decomposition of green and senescent leaves during summer in a headwater stream in northern Japan

Abstract

We conducted a decomposition experiment using green and senescent maple and alder leaves in a coastal headwater stream in Hokkaido, northern Japan, during June and July 2000. We estimated whether shredder colonization on the leaves and leaf breakdown differed between green and senescent leaves during the experimental period. Late-instar Lepidostoma complicatum (Trichoptera) and Sternomoera rhyaca (Amphipoda) were the predominant shredder taxa among the macroinvertebrates that colonized litterbags. There was no significant difference in shredder colonization between green and senescent leaves although we found a significant difference between maple and alder leaves. The colonization patterns of large individuals of L. complicatum and S. rhyaca differed from those of small individuals. All decomposition coefficients of green and senescent leaves were high. During the experiment, decomposition was significantly faster in maple than in alder leaves, although no significant difference was found between green and senescent leaves. However, the fragmented nitrogen portion was higher in green leaves than in senescent leaves during the experiment. Higher nitrogen release (2-2.5 times more) as particulate organic matter in green than in senescent leaves indicates that green leaves may be a potentially valuable food resource for other macroinvertebrate collector-gatherer species.

Breakdown and macroinvertebrate colonization of needle and leaf litter in conifer plantation streams in Shikoku, southwestern Japan

“…Site effect in the ANOVA was assumed to indicate between-site differences in macroinvertebrate abundance, because macroinvertebrate abundance in the litter bags reflects their ambient abundance (litter bags can be regarded as a sampler; e.g., Murphy et al 1998). Among the five taxa examined, gammarid amphipods, lepidostomatid caddisflies and nemourid stoneflies were generally considered as shredders (e.g., Kagaya 1990; Kobayashi and Kagaya 2004;Kochi and Yanai 2006). Leptophlebiid mayflies and many chironomid midges are generally categorized as collector-gatherers.…”

“…When compared in terms of degree day, our result from the summer experiment (k = 0.0051) is similar to that by Kochi (2002) (k = 0.0042). In Japan, like the studies referred to above, study sites where litter breakdown rates were measured are biased toward regions with relatively cool climate (in addition to the above studies: Yanai and Terazawa 1995;Kochi and Yanai 2006 in Hokkaido). Our results indicate that, in southwestern Japan, autumn-shed leaves would decompose and disappear more rapidly than those described in such previous studies in Japan.…”

Environmental conditions and biotic interactions influence ecosystem structure and function in a drying stream

“…Leafpacks were made from fresh sugar maple (Acer saccharum) leaves collected near Little Mulberry Creek, air dried to constant weight, and assembled into 3 g packs with plastic fasteners. Green leaves can be an important high-quality resource for stream detritivores during the summer (Kochi & Yanai, 2006). Six leafpacks (five collections plus a spare leafpack) were installed in each quadrat in June and August.…”

Limnological effects on a first order stream after wood ash application to a boreal forest catchment in Bispgården, Sweden

“…Leaves from deciduous trees, like A. incana, are considered to be an important input of carbon and energy to low order, oligotrophic streams (Vannote et al, 1980;Lepori et al, 2005;Kochi and Yanai, 2006). Thus, although not an aquatic species, leaves from an A. incana stand in the riparian zone at the stream Fanbergsbäcken were analyzed for elemental contents during the investigation period.…”