Nestor Ignacio Gasparri

A peri-urban neotropical forest transition and its consequences for environmental services.

We analyzed changes in land cover in the Sierra de San Javier and its surroundings, an area of ca. 70 000 ha near San Miguel de Tucuman, an urban center of ca. 1 million people in subtropical Argentina. The analysis covered two periods: 1949-1972 and 1972-2006 using remote sensing techniques. For the year 2001, we mapped the patterns of distribution of secondary forests dominated by the most abundant exotic tree species ( Ligustrum lucidum). Based on land-cover maps, we estimated sediment yield as an index of watershed condition. Urban area was growing during the whole study period. Between 1949 and 2006, forest area increased approximately 1400 ha, mostly over abandoned agriculture and grasslands; this expansion was accelerated between 1972 and 2006. Increased forest cover resulted in a reduction in erosion and sediment yield that was disproportionately large, as most new forests are located in areas of steep slopes and high rainfall. By 2001, Ligustum-dominated forests had expanded to more than 500 ha, in the southern portion of the sierra only. Overall, the analysis quantifies a process of Neotropical peri- urban forest transition, likely associated with socioeconomic changes related to population urbanization, that promotes improvements of some environmental services, such as watershed and biodiversity conservation. However, natural communities are strongly affected by past land use and neighboring urban areas, which have promoted a growing importance of exotic species with mostly unknown ecological consequences.

The Transformation of Land-Use Competition in the Argentinean Dry Chaco Between 1975 and 2015

The Dry Chaco in Argentina is among the most dynamic deforestation frontiers in South America. Land-use competition in this region today mainly relates to trade-offs between on the one hand ecosystem services important for local communities (e.g., fuelwood, forage, hunting, subsistence farming) and on the other side global demands for both agricultural commodities (e.g., soybean, beef) and conservation (e.g., of carbon stocks or biodiversity). Over the last four decades, land-use competition in the Dry Chaco has shifted from the local/market mode to the national/politic mode and recently to a global scale under a combination of political and market mode. Different actors and sectors try to shape land-use competition by shifting it onto a scale and into a mode more favorable for their own objectives. On the one hand, the agribusiness sector and provincial governments alike try to conserve land-use competition playing out at local-to-regional scale, with little regulation, and under market forces. On the other hand, local communities (indigenous communities and traditional small-scale farmer cattle ranchers) as well as regional NGOs try to shift land-use competition to the national and even global level. Associated with the upscaling of the competition process, new actors have emerged and become incorporated into land-use competition processes in the Dry Chaco. The national government takes on the role of a mediator to resolve conflicts, but also to create new framework conditions and legislation (most importantly a national Forest Law) for regulating land-use competition. The global community joins land-use competition by adding new options for land use (e.g., carbon stocks, conservation) and by market mechanisms that feedback on producers (e.g., sustainable or green labels). Distal drivers related to agricultural commodity trade, initially, promoted asymmetries in favor of the agribusiness sector. However, in the long run, distal drivers may also act to partially counterbalance the original asymmetries and to result in more balanced outcomes between the often conflicting aspiration of the actors involved in land-use competition in the Dry Chaco of Argentina.

Impacts of the deforestation driven by agribusiness on urban population and economic activity in the Dry Chaco of Argentina

ABSTRACT Agriculture expansion oriented to global market has changed the relation between population and deforestation in South America. Actually, the population dynamic in an agricultural frontier turned into a consequence of deforestation (rather than the cause). For Dry Chaco of Argentina during the period 1991–2001, we explore the impacts of deforestation over urban population and employment dynamics in small- and medium-size urban centers. We used deforestation maps from remote sensing data and demographic information from the national census. We found a positive relation between population growth and deforestation. Additionally, urban centers in a context of new and active deforestation stages generate more jobs than in a context of advanced stages. Based on our results, we suggest a boom and bust pattern. Agriculture expansion and deforestation generate transient jobs and benefits, but in a long-run perspective, positive impacts are uncertain.

C-Band Radiometric Response to Rainfall Events in the Subtropical Chaco Forest

In this letter, multitemporal signatures collected by Advanced Microwave Scanning Radiometer (AMSR-E) over the dry forest of Chaco, located in North Argentina, are analyzed. The forest has a biomass of about 100 t/ha and a woody volume of about 120 m3/ha. A clear increase of polarization index at C-band is observed after intense rain events in two different locations. Simulations of a discrete model attribute this effect to variations of soil moisture and predict an effect comparable with the measured one. Results indicate that there is a potential to monitor soil moisture variations below dry forests with moderate biomass, also in view of the forthcoming availability of L-band data.