CRITICAL AREAS OF LAND COVER CHANGE: AN INDICATOR IN THE FRAMEWORK OF INTEGRATED ASSESSMENT AND MONITORING OF DESERTIFICATION AT LOCAL SCALE. PROVINCE OF MENDOZA, ARGENTINA.

RUBIO, CECILIA; RUBIO, MARÍA CLARA; ABRAHAM, ELENA; SALOMON, MARIO

Cancun

Conferencia; 3rd UNCCD Scientific Conference "Combating desertification, land degradation and drought for poverty reduction and sustainable development",; 2015

UNCCD

The drylands in Mendoza province (Argentina) are fragile ecosystems, subjected to severe and complex processes of desertification (LADA/FAO, 2011), where physical-biological and socioeconomic subsystems interact. As an input to the integrated assessment and monitoring of desertification (Abraham et al., 2006) in the non-irrigated area of the department of Lavalle, NE of Mendoza, we identified the ?Critical areas of land cover change?, an analysis infrequently conducted in desertification studies (Rubio, 2014). Although there is extensive background on assessing land cover and land use changes, most studies address productive humid areas, related to the advancement of soybean monoculture and cattle breeding. Consequently, we proposed to incorporate this indicator into the integrated assessment, in order to define areas susceptible to degradation from the land cover changes experienced in drylands. In these areas, land cover changes bring about strong modifications in the supply of ecosystem goods and services (Daily et al., 1997) and influence the vulnerability of both places and people to climatic, economic or socio-political disturbances. Methods used and partnership set up With the aim to assess land cover changes, we worked with a global scale database, thus supplying the lack of data on land cover and land use layers in the study area for two different years. We used the GlobCover Land Cover product (2005-2006 and 2009), from the European Space Agency (ESA- http://due.esrin.esa.int/globcover/). The thematic legend is compatible with the FAO?s land cover classification system -LCCS- (Di Gregorio and Jansen, 2005), which identifies 23 land-cover classes worldwide, at 300 m spatial resolution. This information can be fit and corroborated at local scale with data on the physiognomy and dominant plant species surveyed in the field (LADA/FAO, 2011). Subsequently, in a GIS environment, we conducted an analysis of land cover changes between years 1 and 2, in the non-irrigated area of Lavalle department. Information layers were processed using the Land Change Modeler for Ecological Sustainability (LCM), integrated into IDRISI software. The LCM includes a set of broad tools to approach the complexity of land cover and land use change. Determination of the areas susceptible to degradation through land cover changes was based on two criteria: type of land cover transition or change, considering those transformations caused by loss of ecosystem goods and services, and therefore having an impact on desertification processes, and the spatial extent of land cover change. Results Outstanding among the main results of the analysis of land cover change in the non-irrigated area of Lavalle department is the fact that the ?Bare areas? class is the one showing the highest growth (67017 ha). In contrast, the ?Forest or shrubland? and ?Closed to open shrubland? classes have notably decreased their surface area (40948 ha and 38217 ha respectively). We determined the critical areas susceptible to degradation from land cover changes. The following transitions between classes were selected: in the first place, the transition from ?Sparse vegetation? to ?Bare areas? (3920.92 ha), second, the transition from ?Closed to open shrubland? to ?Bare areas? (25756.69 ha), and finally, and with the largest transition area identified (35567.2 ha), the change from ?Forest or shrubland? to ?Bare areas? (Fig. 1). The spatial trend of change from ?Forest or shrubland? to ?Bare areas? occurs across the eastern part along the Desaguadero river, in El Forzudo and Arroyito villages; and in the western part, in Asunción and San José villages. The spatial trend of change from ?Closed to open shrubland? to ?Bare areas? again occurs in nearby areas to San José and Asunción villages and to the south of ?Lagunas del Rosario?, which evidences a strong relationship between human pressure and land cover changes that leads to ?Bare areas?. Finally, the spatial trend of change from ?Sparse vegetation? to ?Bare areas? occurs near San José village and in the area corresponding to ?Camino de los Huarpes? which exhibits critical soil and vegetation conditions. Analysis of the spatial trend of change in critical areas within the framework of the integrated assessment of desertification allowed linking it to biophysical and socioeconomic indicators such as stocking rate, population density, aridity index, soil texture, water quality and poverty, among others. Outcomes The constructed indicator, ?Critical areas of land cover change?, is a contribution to strengthening the integrated system for assessing desertification. Applying this indicator in the non-irrigated area of Lavalle department, as a part of the integrated assessment, allowed identification of the major changes and transitions occurred in the area and determination of critical areas of change subjected to loss of related ecosystem services. The newly produced knowledge contributes to territorial decision making for it represents an input to the establishment of sustainable land management practices (SLM), a design to monitor desertification processes and the formulation of measures and strategies for stopping and mitigating these processes. This information contributes to local land management in Mendoza through Law No. 8051/09.