Input, retention, and invertebrate colonization of allochthonous litter in streams bordered by deciduous broadleaved forest, a conifer plantation, and a clear-cut site in southwestern Japan

Abstract

In headwater streams, conifer plantation forestry may affect stream communities through the quantity and quality of basal resources (allochthonous litter). We compared (1) the seasonal patterns of litter input from the riparian canopy, (2) those for the abundance of benthic and drifting litter in streams, and (3) the density of litterassociated invertebrates among streams bordered by deciduous broadleaved forest, a plantation of Japanese cedar (Cryptomeria japonica), and a clear-cut site, to extract the characteristics of conifer-plantation streams in terms of litter dynamics and benthic invertebrates. The results illustrate differences in litter input and in-stream processes between the broadleaved and plantation sites, although the total annual inputs from canopy were similar. In the broadleaved site, high litter storage was limited to winter, probably because pulsed inputs of litter in autumn were retained on the streambed but rapidly processed. In contrast, litter input was more constant at the plantation site, and litter was stored throughout the year. Although the litter-patch-specific density of total invertebrates was similar between the broadleaved and plantation sites, estimates of the reach-scale, habitat-weighted density considering differences in the coverage area of litter patches revealed considerable differences. Although the habitat-weighted density of total invertebrates was lower at the plantation site than at the broadleaved site in winter, it was noticeably higher at the plantation site in summer, owing to the seasonal stability of benthic litter abundance. Our results emphasized the importance of considering the spatiotemporal availability of benthic litter when assessing the effects of conifer plantations on stream ecosystems.

Terrestrial prey inputs to streams bordered by deciduous broadleaved forests, conifer plantations and clear‐cut sites in southwestern Japan: effects on the abundance of red‐spotted masu salmon

“…; Inoue et al. ). These alterations are not necessarily regarded as negative impacts on stream biota.…”

“…Overall, our results suggest that deciduous broadleaved forests provide better food conditions for masu salmon than plantation stands of conifer do. So far, several studies have suggested effects of conifer plantations on stream ecosystems, such as alterations in quality, quantity and seasonal stability of in-stream detritus and taxonomic composition of its consumer assemblages (benthic invertebrates) (Murphy & Giller 2000;Yoshimura 2007;Riipinen et al 2010;Hisabae et al 2011;Inoue et al 2012). These alterations are not necessarily regarded as negative impacts on stream biota.…”

Calcium concentration in leaf litter affects the abundance and survival of crustaceans in streams draining warm–temperate forests

“…Recent studies have shown that the abundance or density of gammarid amphipods is significantly greater in streams that in drain Japanese cedar plantations than in those that drain deciduous broad-leaved forests (Hisabae, Sone & Inoue, 2010;Inoue et al, 2012;Sakai et al, 2013). These authors argue that greater invertebrate abundances/densities are the result of C. japonica litter Total calcium in water (μmol c L -1 ) Survival rate of Gammarus nipponensis P < 0.001 Fig.…”

“…The drastic decrease in G. nipponensis by logging also affected the invertebrate community structure, similar to that at EB, although the community structure at CC and EB was still distinctively different. Gammarid amphipods are not tolerant of physical disturbances, such as flash floods, debris flows or drought (Inoue et al, 2012;Kobayashi et al, 2013). Such severe physical disturbances in clear-cut areas might partly affect the density and survival of G. nipponensis and community composition of the invertebrates.…”

Effects of Exotic Tree Plantations on Plant Litter Decomposition in Streams

“…Most conifer species planted are evergreen, and thus create important differences in the timing of litter inputs to streams compared with streams flowing through deciduous forests where trees shed leaves in autumn (Inoue et al, 2012;Martínez et al, 2016). Consequently, while in streams flowing through deciduous forests there is a peak of benthic storage of coarse particulate organic matter (CPOM) in autumn, litter storage in conifer streams shows less variation throughout the year (Inoue et al, 2012;Martínez et al, 2016). Nevertheless, CPOM annual budgets are often similar between both stream types (Martínez et al, 2013(Martínez et al, , 2016Miserendino & Masi, 2010;Riipinen et al, 2009).…”