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Biogeochemical properties of fine particulate organic matter as an indicator of local and catchment impacts on forested streams
Author(s) -
Sakamaki Takashi,
Richardson John S.
Publication year - 2011
Publication title -
journal of applied ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.503
H-Index - 181
eISSN - 1365-2664
pISSN - 0021-8901
DOI - 10.1111/j.1365-2664.2011.02038.x
Subject(s) - riparian zone , environmental science , streams , biogeochemical cycle , ecosystem , benthic zone , ecology , river ecosystem , vegetation (pathology) , hydrology (agriculture) , habitat , geology , biology , geotechnical engineering , pathology , computer science , medicine , computer network
Summary 1. The magnitude and spatial scales of human effects on stream habitats need to be correctly measured to achieve sound ecosystem management. We investigated whether the biogeochemical properties of fine particulate organic matter (FPOM) might be indicative of reach‐scale vs. catchment‐scale effects on forested stream ecosystems. 2. Along each of three forested streams, we established 4–5 sampling stations at 0·6–2·0‐km intervals, which represent a range of local riparian forest conditions (e.g. vegetation types and forestry practices). At each station, rock biofilm (considered as a representative of stream‐origin POM), FPOM in sediment (FPOM S ) and suspended in water (FPOM W ) and three species of benthic macroinvertebrates were collected during a summer low‐flow period. 3. Measures of δ 13 C, C:N and chlorophyll a :C for FPOM W , FPOM S and biofilm were longitudinally heterogeneous, reflecting the reach‐scale, local environment. δ 13 C, C:N and chlorophyll a :C of FPOM S were significantly related to irradiance and streambed coarse particulate organic matter (CPOM) abundance, suggesting that the relative contribution of in‐stream primary production and CPOM breakdown are dominant controls of FPOM properties. 4. In redundancy analysis, variations in FPOM properties were principally explained by local environmental factors correlated with stream size and/or longitudinal position of the sampling stations (irradiance, streambed CPOM, stream gradient, discharge, riparian vegetation). No significant effect of riparian forestry activities (logged, riparian reserve or no harvest in the past 75 years) was found on FPOM properties. 5. Resource use by primary consumers was species dependent. δ 13 C of larval Lepidostoma roafi depended on the relative abundance of stream‐origin POM in pools of stored FPOM. Selective intake/assimilation of stream‐origin POM by this species was probably enhanced when stream‐origin POM was abundant. δ 13 C of larval Despaxia augusta or larval Paraleptophlebia spp. were not related to FPOM S δ 13 C, suggesting no linkage with FPOM composition. 6. Synthesis and applications . The tight linkages between biogeochemical properties of FPOM, resource use by primary consumers, and reach‐scale environment indicate that local effects were greater than signals transmitted from upstream in this study. The use of in‐stream FPOM properties can help managers to measure reach‐scale effects of environmental changes on forested stream habitats.