N. Ignacio Gasparri

Globalization and soybean expansion into semiarid ecosystems of Argentina.

Deforestation is the product of complex interaction among local idiosyncratic properties of natural and social systems and driving forces that commonly operate at large spatial scales (1). Social and economic globalization, particularly reduced communication and transportation barriers, has increased the relative importance of global drivers of environmental change (e.g. deforestation). For example, agriculture expansion is increasingly influenced by technological changes that are rapidly disseminatedworldwide (2) and by changes in consumption patterns of a few countries that have a disproportionate influence on the global markets because of their large population (e.g. China) or high levels of consumption (e.g. USA, European Union). The increased importance of soybean production in the global economy is an example of how local and global factors can interact and have large effects on natural systems. A number of characteristics of soybean havemade it an attractive crop in the globalized context. Soybean has low water content, high nutritive value, and the capacity to yield a variety of products (e.g. human food, animal food, oil, and industrial derivates) (3). These characteristics reduce vulnerability tomarket fluctuations, reduce storage and transportation costs, and have contributed to its rapid expansion. Furthermore, the increasing global demand for soybean products has resulted in large investments in research and development and the widespread use of transgenic cultivars that have increased yields, reduced costs by reducing herbicide use, and increased the range of appropriate planting environments (4). A major factor influencing the growing demand for soybean has been a global increase inmeat consumption (5), much of which is produced with soybean meal. Until 1993, China was a major exporter of soybeans, but the increasing demand for meat, particularly pork and chicken, associated with the socioeconomic changes during the last 10 y has converted China into the number one soybean importer in the world (6). This increasing demand for soybeans is reflected in a doubling in planted area during the last 30 y (7). Globally, approximately 80 million ha are planted in soybean, and .70% is in the United States, Brazil, and Argentina. During the last 10 y, production in the United States has been relatively stable, but South America has experienced a dramatic increase, much of which was established by deforesting extensive areas of tropical dry forest (3, 4, 8). In this communication, we describe how increasing demand, technological advances, and climate change are driving soybean expansion in Argentina and seriously jeopardizing the integrity of extensive semiarid biomes.

Land-use and land-cover effects on regional biodiversity distribution in a subtropical dry forest: a hierarchical integrative multi-taxa study

Abstract Latin American subtropical dry ecosystems have experienced significant human impact for more than a century, mainly in the form of extensive livestock grazing, forest products extraction, and agriculture expansion. We assessed the regional-scale effect of land use and land cover (LULC) on patterns of richness distribution of trees, birds, amphibians, and mammals in the Northern Argentine Dry Chaco (NADC) over c. 19 million hectares. Using species distribution models in a hierarchical framework, we modeled the distributions of 138 species. First, we trained the models for the entire Argentinean Chaco with climatic and topographic variables. Second, we modeled the same species for the NADC including the biophysical variables identified as relevant in the first step plus four LULC-related variables: woody biomass, distance to crops, density of livestock-based rural settlements (puestos), and vegetation cover. Third, we constructed species richness maps by adding the models of individual species and considering two situations, with and without LULC variables. Four, richness maps were used for assessing differences when LULC variables are added and for determining the main drivers of current patterns of species richness. We found a marked decrease in species richness of the four groups as a consequence of inclusion of LULC variables in distribution models. The main factors associated with current richness distribution patterns (both negatively) were woody biomass and density of livestock puestos. Species richness in present-day Semiarid Chaco landscapes is strongly affected by LULC patterns, even in areas not transformed to agriculture. Regional-scale biodiversity planning should consider open habitats such as grasslands and savannas in addition to woodlands.

The role of bioclimatic features, landscape configuration and historical land use in the invasion of an Asian tree in subtropical Argentina

ContextKnowing which factors determine the spread of plant invaders is a relevant issue in global ecology. Cultural landscapes both influence and are affected by exotic species. Although bioclimatic boundaries, seed sources and landscape configuration all control the invasion process, they have been mostly studied separately and independently from their distant drivers.ObjectivesWe followed a multiscale approach to describe the invasion dynamics of the Asian tree (Ligustrum lucidum) in subtropical NW Argentina cultural landscapes by: (1) identifying the potential bioclimatic area of invasion, (2) mapping the currently invaded area in peri-urban focal sectors, and (3) quantitatively describing the landscape-scale patterns of invasion in relation to environmental and cultural variables.MethodNiche models were used to map potential invasion area, remote sensing, GIS and field surveys to map patterns of invasion and their association to landscape and environmental variables.ResultsClimate suitability to L. lucidum extends over important ranges of the studied area, but currently invaded areas are mostly restricted to clusters around the main cities. The historical and demographic features of cities (e.g., date foundation, population) are important in predicting invaded forest location and spread. At local scale, invasion is associated to abandoned fields nearby urban centers, roads and rivers.ConclusionsThe invasion patterns of L. lucidum reflect the combined effect of historical socioeconomic connections between Asia and America, as well as the local cultural landscape history and configuration. Teleconnected cultural landscapes need to be explored as a theoretical framework for the study of biological invasions in the Anthropocene.