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Harvard Forest Symposium Abstract 2011
- Title: Land sparing vs. Land sharing in the Gran Chaco: the case of the Argentinean province of Santiago del Estero
- Primary Author: Cristina Herrero (Harvard Forest-Real Colegio Complutense)
- Additional Authors: Magdalena Abt (Universidad Nacional de Santiago del Estero); Miguel Brassiolo (Universidad Nacional de Santiago del Estero); David Foster (Harvard University); Analía Guzmán (Universidad Nacional de Santiago del Estero); Fabian Reuter (Universidad Nacional de Santiago del Estero); Florencia Sangermano (Clark Labs, Clark University); elia machado (Clark University)
- Abstract:
The impact of Land Use and Land Cover Change (LULCC) is a major issue in conservation biology. The vast plain known as the Gran Chaco is a natural region of more than 1.2 million Km2 which extends over a great portion of Argentina, Bolivia, Paraguay and a small area of Brazil. Estimates suggest that in the last 30 years, 85% of undisturbed Chaco forest has been converted to pastures and agricultural lands or is undergoing secondary succession with various ecological and social consequences. Land sparing, or the intensification of an export-oriented agriculture to respond to increasing world food demands while sparing land for nature conservation, is the dominant current land use strategy for the Argentinean Chaco, which is suffering high rates of land use change mainly from forests to soybean plantation fields and to unproductive shrub lands. The land sparing hypothesis predicts recovery of degraded forests due to rural-urban migration, a process that accompanies agricultural intensification. This contrasts with previous degradation driven by low intensity farming associated with traditional puestos, scattered throughout the region. This type of land use degrades primary forest, thereby hindering the survival of some flag species, such as the jaguar or the chacoan peccary. On the other hand, the land sharing hypothesis maintains that a matrix of degraded forest is more suitable than a mosaic of intensive agricultural fields and nature reserves for the maintenance of ecosystem services and social wellbeing, including issues of food sovereignty and social justice that are not usually incorporated in land sparing analyses, thus broadening the focus. It is important to understand what land patches are converting to what and in which ways socio-economic and ecological variables interrelate, as a first step in identifying the driving factors of this rapid land use change. This understanding will enable modeling of future scenarios, either under land sparing or under land sharing support politics, which may be used as a basis for future research hypotheses and as planning tools for policy makers.
Based on the northern Argentinean province of Santiago del Estero (Fig. 1) this research seeks to answer the following questions: i) Which land use/land cover change dynamics characterize the region? ii) Given the present conditions, what would be the most probable land use scenario of change? iii) Is Land Sparing actually occurring in the region, or is it possible to predict it will occur? iv) If it is, which is the critical threshold at which it occurs? v) What are the conditions that would make Land Sharing a sustainable option for the region? We present the following preliminary results: i) a historical analysis of LULCC in the region, and ii) the empirical modeling of LULCC. This analysis was based on the supervised classification of three MODIS images (2004, 2007, 2010; Fig. 2), the quantification of landscape dynamics and the empirical prediction of changes through a Neural Network Markov algorithm, using seven explanatory variables.
Preliminary results show conversion rates of primary forests of 14% each year. This conversion was towards agriculture and pastures in a 63% and to degraded forests in a 30%, mainly in the eastern side of the province. Distance to cultivations and pastures and distance to roads were the variables that best predicted LULCC. Distance to villages enhanced the conversion of primary forest but not of degraded forest. Given current conditions, model predicts a loss of 58% of forest cover for 2050. We calculated an error of 28% for this prediction due, among other things, to the atypicality of the 2007 data. The lower rate of forest transformation within reserve boundaries suggests that these designations seem to work. These preliminary analyses do not support a process of Land Sparing going on in the Province. - Research Category: Conservation and Management
International Research Projects
Regional Studies - Figures: Fig. 1.jpg
Fig. 2.jpg
