Comparative study of the floristic composition, diversity and productivity of the wet meadows or mallines of Tierra del Fuego, Chile

Abstract

 Wet meadow or mallines from a functional and productive point of view, are a fundamental component in the livestock systems of Patagonia, as they are the main source of forage. With the working hypothesis that, the generation of knowledge about the floristic diversity and productivity of the different types of plains present in Magallanes, will promote a sustainable livestock management of these, which, in turn, will guarantee the conservation of the functions and wet meadow ecosystem services. Between January 2019 and May 2020, a study was carried out in six estancias on the Island of Tierra del Fuego, Chile, to describe the taxonomic components, compare the diversity of plant species, evaluate the floristic similarity, along with analyzing the temporal distribution from plant biomass to the exclusion of herbivory that characterize these ecosystems. A total of 53 taxa were recorded, distributed in 16 families (Poaceae, Rosaceae, Cyperaceae, Apiaceae and Asteraceae, mainly) and 40 genera, of which 40 species are native and 11 introduced to the plains. The wet meadows analyzed presented specific richness values and diversity indices lower than those found in Patagonia Argentina. The floristic composition and the attributes of the vegetation showed patterns linked to the water content of the soil, observing a negative relationship between the water table and the values of richness and diversity indices. Regarding vegetation cover, the humid sectors presented higher percentages of vegetal cover than those of the semi-humid sectors. Finally, it was determined that the wet meadows are not homogeneous in their composition of species, nor in their structure, they show evidence of changes in their floristic diversity, due to the impacts generated by the intensity of grazing, which is reflected in forage production, fluctuating between 408 to 4,055 kg DM ha-1.