Invasive Salix fragilis alters benthic invertebrate communities and litter decomposition in northern Patagonian streams

• Published in: Hydrobiologia Vol. 701; no. 1; pp. 173 - 188
• Main Authors: Serra, María Noel, Albariño, Ricardo, Díaz Villanueva, Verónica
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.01.2013; Springer; Springer Nature B.V
• Subjects: Animal and plant ecology; Animal populations; Animal, plant and microbial ecology; Applied ecology; Aquatic animals; Aquatic environment; Aquatic life; Benthic fauna; Biological and medical sciences; Biomass; Biomedical and Life Sciences; Biota; Conservation, protection and management of environment and wildlife; Creeks & streams; Decomposition; Ecological function; Ecology; Ecosystems; Fresh water ecosystems; Freshwater & Marine Ecology; Fundamental and applied biological sciences. Psychology; General aspects; Invertebrata; Invertebrates; Leaf litter; Leaves; Life Sciences; Nonnative species; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Primary production; Primary Research Paper; Riparian ecology; Riparian vegetation; Salix fragilis; Species composition; Streams; Synecology; Trees; Zoology; South America; America; South America, Andes Mts; Detritivores; Willow; Riparian vegetation; Exotic; Biological invasion; Zoobenthos; Decomposition; Patagonia; Freshwater environment; Aquatic environment; Salix; Dicotyledones; Angiospermae; Stream; Detritivorous; Benthic organism; Litter; Woody plant; Salicaceae; Invasive species; Biocenosis; Spermatophyta; Invertebrata; Environmental monitoring; Environmental protection; Ochetophila trinervis
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1007/s10750-012-1270-2

Invasion by exotic trees into riparian areas has the potential to impact aquatic systems. We examined the effects of the exotic Salix fragilis (crack willow) on the structure and functioning of small streams in northern Patagonian Andes via a field survey of benthic invertebrates and leaf litter and an in situ experiment. We compared leaf decomposition of the native Ochetophila trinervis (chacay) and S. fragilis in reaches dominated by native vegetation versus reaches dominated by crack willow. We hypothesized that S. fragilis affects the quality of leaf litter entering the streams, changing the aquatic biota composition and litter decomposition. Our study showed that crack willow leaves decomposed slower than chacay, likely related to leaf properties (i.e., leaf toughness). Benthic leaf litter mass was similar between the two riparian vegetation types, though in stream reaches dominated by crack willow, leaves of this species represented 82% of the total leaf litter. Benthic invertebrate abundance and diversity were similar between reaches but species composition differed. Our study found little evidence for strong impacts of crack willow on those small streams. Further studies on other aspects of ecosystem functioning, such as primary production, would enhance our understanding of the impacts of crack willow on Patagonian streams.