Data di Pubblicazione:
2017
Abstract:
Clogging, the streambed colmation by fine sediments, is an important widespread source of impact affecting
freshwaters. Alterations in stream morphology and hydrology, added to the effects of global climate change,
are responsible for this phenomenon, that is particularly pernicious in mountainous lotic systems naturally characterized
by coarse substrates. Among the studies investigating this issue some were descriptive, while others
used artificial substrates to compare ongoing fine sediment accumulation andmacroinvertebrate assemblage recruitment.
Other studies used from the outset artificial substrates arranged with different levels of clogging. Our
study fits into this line, but adding an innovative element simulating different availability of coarse particulate
organic matter, i.e. the main trophic input in low-order, mountainous stream. To investigate how clogging and
CPOM can influence macroinvertebrate communities, we placed 135 artificial substrates in the upper Po river
(NW Italy). We set up a three way factorial design with three different levels of sedimentation and terrestrial
leaf material. Artificial substrates were removed on three different dates. Benthic invertebrates were identified
and classified according to their bio-ecological traits. We also measured macroinvertebrate dry mass and
CPOMdegradation in the different trap types. Our findings showthat clogging acts as a selective filter influencing
taxa richness, density, functional composition and biomass of benthic assemblage. Moreover, fine sediments affect
the energetic dynamics in the river ecosystem, decreasing themass loss rate of terrestrial leaves. Interestingly,
our results clearly demonstrate that high availability of CPOM can buffer the negative effect of clogging,
suggesting that an adequate input of allochthonous organic matter may lessen the impact of fine sediment
Tipologia CRIS:
03A-Articolo su Rivista
Keywords:
hydrological alterations, climate change, fine sediments, benthic macroinvertebrates, allochthonous organic matter, functional groups
Elenco autori:
Doretto, Alberto; Bona, Francesca; Piano, Elena; Zanin, Ilaria; Eandi, Anna Chiara; Fenoglio, Stefano
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