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Effects of exotic eucalypt plantations on organic matter processing in Iberian streams
Author(s) -
Larrañaga Santiago,
Larrañaga Aitor,
Basaguren Ana,
Elosegi Arturo,
Pozo Jesús
Publication year - 2014
Publication title -
international review of hydrobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 52
eISSN - 1522-2632
pISSN - 1434-2944
DOI - 10.1002/iroh.201301665
Subject(s) - environmental science , riparian zone , plant litter , streams , biomass (ecology) , litter , organic matter , deciduous , ecosystem , alder , ecology , decomposer , riparian forest , vegetation (pathology) , biology , habitat , medicine , computer network , pathology , computer science
Eucalypt leaves are an organic matter source of poor quality, and therefore, extensive eucalypt plantations can affect stream ecology. Nevertheless, it is difficult to discern the effects of altered inputs from other impacts of plantations, such as increased erosion from periodic clearcuttings. To assess the effects of eucalypt inputs on organic matter decomposition in streams, we manipulated litter inputs in two headwater streams in the north of the Iberian Peninsula. Three contiguous 50‐m long reaches were selected per stream: the upstream reference reach was left unaltered, while the others were covered and separated by mesh to prevent inputs from the surrounding vegetation, and via downstream transport. Regularly, we provided the covered sites with either native deciduous (middle reach) or eucalypt (lower reach) leaf litter, mimicking the amount and seasonality of inputs from the respective forest types. Two decomposition experiments with alder and eucalypt leaves were performed half a year and 1 year after the beginning of the exclusion of natural inputs. Decomposition for both species was lower in sites receiving eucalypt leaf litter, corresponding with the lower density of shredders in these sites. Moreover, higher alder:eucalypt macroinvertebrate density and biomass ratios in sites receiving eucalypt inputs suggest that invertebrates concentrated on the higher quality alder leaves in those sites. Our study shows that eucalypt inputs can impair stream ecosystem processes in a short time span and suggests that maintaining native leaf litter inputs into streams by intact riparian corridors could help to mitigate the effect of eucalypt plantations on streams.