Vegetal species composition, distribution and abundance of a region affected by gold mine environmental liabilities.

MARTÍNEZ, BELÉN; ROQUEIRO, GONZALO; MONETTA PABLO; YOUNG, BRIAN JONATHAN; MARIANA MARTINELLI; TAPIA, RAÚL.

Buenos Aires

Congreso; Congreso SETAC; 2015

Metal mining and especially gold-mining represents important economic activities in South-America. It is known that mining activities may generate environmental liabilities due tounplanned disposal of residues, affecting different components of a given ecosystem. Changeson pedalogical conditions induce responses on native vegetation that can be expressed bydifferent parameters. In this sense, the aim of the present work was to evaluate floralcomposition, distribution and abundance of vegetal species as a baseline to determine therelationship between vegetation and gold mine environmental liabilities in an area located atthe northeast of San Juan province (Argentina). On base of visual interpretation of a Landsat 8image using QGis, the study area was divided on three subunits: Upstream, Downstream andInhabited area. On each subunit a combined sampling was performed. Transects and squareswere performed to quantify different variables. Transects were 50 m long and randomlydistributed. The number of transects was calculated as N≥ [( ds.T)/ (1-p). )]2. Squares had 4m2 and were realized every 10 m. Floral diversity was calculated by Shannon and Simpsonindexes. Results shown that upstream subunit was the most diverse followed by downstreamand inhabited area (Shannon index: 0.07, 0.05 and 0.02 respectively). Upstream subunit wasalso the less dominant followed by inhabited area and downstream (Simpson index: 0.002,?0.01). In agreement with index results, richness analysis indicates that inhabited areapresented the lower value (26, 21 and 13 species respectively). Finally, regarding to density ofspecies, Aristida mendocina was the densest in all subunits evaluated, presenting values of 5.6,2.69 and 2.15 individuals/m2 in upstream, downstream and inhabited area respectively.Strikingly, A. mendocina was significantly reduced in downstream and inhabited sector. Takingtogether the obtained results suggest that vegetation presents variations on floral, distributionand abundance of species among different subunits evaluated. Undoubtedly, further researchis necessary to understand weather these variations are related to changes in pedalogicalconditions induced by the abandoned gold mine environmental liabilities.