Short term effects of wildfire on Patagonian headwater streams

WILLIAMS SUBIZA, E.A.; BRAND, C.

INTERNATIONAL JOURNAL OF WILDLAND FIRE

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2018 p. 457 - 470

1049-8001

In March-April, 2015 the El Cristo fire burned 1228 ha of mixed Nothofagus forest in Los Alerces National Park (Argentine Patagonia). Effects on first order streams were examined by comparing environmental variables and benthic communities from burned and unburned streams. Sampling began shortly after the fire was extinguished and comprised periodic water quality assessments and four visits to collect periphyton and invertebrate samples (May, August, October and December). Fire significantly altered water temperature, total dissolved solids, total suspended solids, and specific conductance. No major differences in nutrient or oxygen concentrations were found when comparing burned and unburned streams. Chlorophyll a (used as a surrogate for autotrophic periphyton biomass) also did not differ significantly. Macroinvertebrate taxonomic richness, abundance and diversity showed no differences across sites, but taxonomic composition and densities of sensitive taxa were markedly lower at burned streams, while oligochaete and amphipod abundances increased. Functional feeding groups were also affected, reductions in relative abundances of shredders and collector-filterers occurred at affected sites, reflecting a shift in detrital input.