Scholarly Articles
Dominance of Autochthonous Trophic Base in Northeast Asian Stream Food Webs Pre- and Post-monsoon
Journals
Ecological Indicators
Author
신재기
Publication Date
20220806
Spatial and temporal variability in the trophic base of food webs is an inevitable ecological attribute in aquatic
ecosystems with the role of aquatic and terrestrial sources varying from system to system. Despite high algal
biomass, an apparent increase in terrestrial detritus during the East Asian summer monsoon would be expected to
alter the dominant food web base from the pre- to post-monsoon period. The δ13C and δ15N values of common
aquatic invertebrates and fish were compared with those of their potential sources of organic matter across the
upstream channel and lacustrine habitats during the pre- and post-monsoon periods in the Se-oak Stream system
of Korea. The purpose was to identify the variability in trophic structure (niche and diversity) at the community
level and to quantify the contribution of terrestrial and aquatic carbon sources to the food web base. The δ13C
and δ15N values of the major potential organic matter sources differentiated allochthonous leaf litter and riparian
vegetation from autochthonous biofilm and seston, but with no significant spatial and temporal changes. The
δ13C values of consumers fell within a narrower range than that of organic matter sources, consistent with the
instream biofilm and seston values. However, the consumer δ15N values spanned a broad range, increasing from
invertebrates to fish. The resultant niche overlaps of consumers in the isotopic niche space between seasons and
locations, their narrower horizontal niche breadths compared to organic matter sources, and the isotope mixingmodel
estimates indicated that aquatic production was the primary source of organic matter supporting the
aquatic food webs. Overall, the results revealed a consistent dominance of autochthonous trophic bases in both
lotic and lentic food webs before and after the summer monsoon. Our findings, which highlight the trophic
importance of aquatic algal production facilitated by anthropogenic nutrients in this shallow, low-turbidity, and
well-illuminated stream food web, may provide insight into ecosystem processes that counteract potential
terrestrial-aquatic links to influence food web dynamics based on natural nutrient sources in deep, highly turbid,
or shaded stream counterparts.
ecosystems with the role of aquatic and terrestrial sources varying from system to system. Despite high algal
biomass, an apparent increase in terrestrial detritus during the East Asian summer monsoon would be expected to
alter the dominant food web base from the pre- to post-monsoon period. The δ13C and δ15N values of common
aquatic invertebrates and fish were compared with those of their potential sources of organic matter across the
upstream channel and lacustrine habitats during the pre- and post-monsoon periods in the Se-oak Stream system
of Korea. The purpose was to identify the variability in trophic structure (niche and diversity) at the community
level and to quantify the contribution of terrestrial and aquatic carbon sources to the food web base. The δ13C
and δ15N values of the major potential organic matter sources differentiated allochthonous leaf litter and riparian
vegetation from autochthonous biofilm and seston, but with no significant spatial and temporal changes. The
δ13C values of consumers fell within a narrower range than that of organic matter sources, consistent with the
instream biofilm and seston values. However, the consumer δ15N values spanned a broad range, increasing from
invertebrates to fish. The resultant niche overlaps of consumers in the isotopic niche space between seasons and
locations, their narrower horizontal niche breadths compared to organic matter sources, and the isotope mixingmodel
estimates indicated that aquatic production was the primary source of organic matter supporting the
aquatic food webs. Overall, the results revealed a consistent dominance of autochthonous trophic bases in both
lotic and lentic food webs before and after the summer monsoon. Our findings, which highlight the trophic
importance of aquatic algal production facilitated by anthropogenic nutrients in this shallow, low-turbidity, and
well-illuminated stream food web, may provide insight into ecosystem processes that counteract potential
terrestrial-aquatic links to influence food web dynamics based on natural nutrient sources in deep, highly turbid,
or shaded stream counterparts.