Livestock impact over understory plant and beetle communities in grasslands and forests under silvopastoral use in Tierra del Fuego, Argentina.

MV LENCINAS; R SOLER ESTEBAN; G MARTÍNEZ PASTUR; PL PERI; JM CELLINI; MD BARRERA

Evora

Congreso; World Congress Silvo-pastoral Systems.; 2016

University of Evora

Livestock (sheep and cattle) have a strong influence over soils in grasslands and over forests under silvopastoraluse, affecting biodiversity, e.g. composition and abundance of understory plant and beetle communities.The aim of this work was to analyze the impact of different livestock grazing intensities on understory plant andbeetle communities of natural grasslands and Nothofagus antarctica forests in Tierra del Fuego, Argentina,evaluating the differential effect of cattle and sheep.Sampling was conducted in 12 N. antarctica stands and 18 grassland sites in north-central Tierra del Fuego Island,using established fences at each site to evaluate two grazing intensities (high and low) between the two sides ofeach fence, which was confirmed by feces counting. Also, two livestock types (cattle and sheep) were considered.At each site, vegetation was characterized by composition and cover, while pit-fall traps were used to evaluaterichness and abundance of beetles.Plant communities differed between N. antarctica forests and grasslands, and high grazing intensity did notinfluence these differences. These were associated with greater soil moisture and higher herbaceous layer.However within habitat types, sites with high grazing intensity doubled exotic monocot covers compared with lowgrazing intensity sites.On the other hand, beetle richness was similar between grasslands and forests, and also between grazingintensities, but sites with cattle had less richness than sites with sheeps. Furthermore, sheep sites had 3-foldgreater beetle abundance compared to cattle sites, and the same was found when comparing between low andhigh grazing intensities for sheep. Complementarily, sites with cattle had similar richness between grazingintensities, but sites with sheep showed a 5-fold greater richness in high compared to low grazing intensities.Different livestock types and grazing intensities did not greatly affect plant community composition, although highgrazing intensity allowed for the establishment and growth of exotic plants. Beetle communities were moresensitive to sheep than cattle production, as well as to grazing intensity, increasing richness and abundance byfacilitating the entrance of species from associated environments, and/or increasing the abundance of somespecies. These studies improve the knowledge of these austral ecosystems to allow the design of furtherconservation strategies through silvopastoral and grassland management.