Hydrological disturbance overrides the effect of substratum roughness on the resistance and resilience of stream benthic algae
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Data
2012-06-14
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Resumo
Habitat heterogeneity in lotic systems is usually associated with the availability of refuges.
Heterogeneous habitats (here, rough substrata) should mediate the effect of high-flow disturbances
by protecting benthic algae, thus increasing the resistance and resilience of the system.
Additionally, the ability of algae to resist a disturbance and recover after it should be dependent
on biological traits that confer resistance and resilience.
2. We designed a field experiment, simulating a high-flow event with bed movement, to test the
effect of substratum roughness on the resistance (assessed as the similarity between samples
collected before and immediately after disturbance) and resilience (the similarity between samples
collected before and 7 and 15 days after disturbance) of five algal life forms. We evaluated
whether algal resistance and resilience were higher on rough than on smooth substrata, and
whether the life forms differed in their ability to resist and recover from a disturbance.
3. Rough substrata had higher species richness than smooth substrata at all sampling periods, even
immediately after the disturbance. There was no significant effect of substratum roughness on
algal resistance and resilience, for both species richness and density of the total assemblage.
Neither did roughness affect the resistance and resilience of the total algal assemblage or of the
algal life forms separately, when evaluated using multivariate data sets (presence-absence and
quantitative).
4. Algal life forms differed in resistance and resilience; adnate ⁄prostrate and erect⁄ stalked species
were more resistant and resilient than the other life forms (filamentous, motile and metaphytic).
Additionally, motile species resisted and recovered better than did species that are only loosely
associated with the substratum (metaphytic species).
5. Substratum roughness had no pronounced effect on benthic algal resistance and resilience. The
results of this and some other studies suggest that the intensity of disturbance determines the
importance of habitat heterogeneity and flow refuges for benthic algae in streams.
Descrição
v. 57, p. 1678-1688, 2012.
Palavras-chave
Algal life form, Floods, Habitat heterogeneity, Periphyton, Refuges
Citação
SCHNECK, F.; MELO, A. S. Hydrological disturbance overrides the effect of substratum roughness on the resistance and resilience of stream benthic algae. Freshwater Biology , v. 57, p. 1678-1688, 2012. Disponível em: <http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2427.2012.02830.x/epdf>.