Using Participatory Research, Remote Sensing and Field Surveys to Build a State and Transition Model for the Native Pastures of Northern Uruguay

Native grasslands cover 55% of the agricultural lands of Uruguay. Balancing conservation, agricultural production and human well-being is a major management challenge. Adaptive management approaches have been developed for leased land, underpinned by a newly developed state and transition model (STM). The model was tested in northern Uruguay, in the Department of Paysandú, covering an area of 8300 ha. Floristic surveys were used to define five states, based on the relative cover of key plant species and functional types. Each state was characterized in terms of livestock density, sheep/cattle ratio and years since last ploughing. Aboveground Net Primary Production (ANPP) data were derived from MODIS NDVI data using the Monteith model. Total production and ANPP, including seasonal and inter-annual variability, were characterized for each state. Hypotheses on the drivers of the transitions between states of degradation were derived from local studies on the effect of grazing and cropping on grassland structure and function. A participatory engagement process with local stakeholders was used to develop actions that focused on managing the heterogeneity of forage resources and the desired transitions between states