Inter-Annual and Habitat Variation of the Mayfly Assemblage in Grassland and Pine Afforested Headwater Streams (Córdoba, Central Argentina)

MONTILLA V.; PRINCIPE R. E.; MARQUEZ J. A.

Champaign

Conferencia; 2022 XVITH INTERNATIONAL CONFERENCE ON EPHEMEROPTERA AND XXTH INTERNATIONAL SYMPOSIUM ON PLECOPTERA; 2022

University of Illinois, Illinois Natural History Survey, Champaign

Mayflies are widely used as indicators of stream conditions since their presence and abundanceare closely associated with changes in environmental characteristics. We aim to analyze therichness and abundance patterns of mayflies in headwater streams of the Ctalamochita Riverbasin in central Argentina, where some sub-basins have been fully afforested with exotic pines.We sampled 3 grassland streams and 3 pine afforested streams in 2008, 2012, 2014, and 2015.We took Surber samples in riffles, and in 2012 we also sampled 2 additional habitats: pools andmacrophyte patches. We found 9 mayfly genera. Americabaetis spp. was the most frequent andabundant while Cloeodes spp., Farrodes spp. and Tricorythodes spp. were the least ones, with arelative frequency < 3%. Richness and abundance were higher in grassland streams (ANOVA, p< 0.05), but the abundance pattern of different mayfly genera varied. In 2012 mayfly abundancewas higher in pools and macrophytes in the afforested streams (ANOVA, p < 0.05), but it wassimilar among habitats in grassland streams. Americabaetis spp. dominated in macrophytepatches while Baetodes spp. and Nanomis spp. in riffles. Caenis spp. dominated in pools but itwas also abundant in macrophytes in the afforested streams. Leptohyphes spp. dominates inriffles but it was also abundant in macrophytes in the grassland streams. Callibaetis spp. wasonly found in grassland streams in pools and macrophyte patches. Distribution patterns areinfluenced by microhabitat characteristics which may be conditioned by changes in riparian landuses.