Synergistic combinations of climatic and land use changes have the potential to produce the most dramatic impacts on land cover. Although this is widely accepted, empirical examples, particularly involving deforestation in Latin America, are still very few. The geographic extent and causes of deforestation in subtropical seasonally dry forests of the world have received very little attention. This is especially true for the Chaco forests in South America, which are being lost at an alarming rate, sometimes higher than those reported for tropical forests. On this basis, the aims of this study were to analyze the changes in land cover that have occurred during the last three decades of the 20th century in the Chaco forests of central Argentina, and to explain the factors that have driven those changes. Results show major land cover changes. Approximately 80% of the area that was originally undisturbed forest is now occupied by crops, pastures, and secondary scrub. The main proximate cause of deforestation has been agricultural expansion, soybean cultivation in particular. This appears as the result of the synergistic convergence of climatic, technological, and socioeconomic factors, supporting the hypothesis of a multiple-factor explanation for forest loss, while providing one of the very few existing analyses of changes in subtropical forests of the world.

What drives accelerated land cover change in central Argentina? Synergistic consequences of climatic, socioeconomic, and technological factors.

How does nature work in our human-created city, suburb, and exurb/peri-urb? Indeed how is ecology - including its urban water, soil, air, plant, and animal foundations - spatially entwined with this great human enterprise? And how can we improve urban areas for both nature and people? Urban Ecology: Science of Cities explores the entire urban area: from streets, lawns, and parks to riversides, sewer systems, and industrial sites. The book presents models, patterns, and examples from hundreds of cities worldwide. Numerous illustrations enrich the presentation. Cities are analyzed, not as ecologically bad or good, but as places with concentrated rather than dispersed people. Urban ecology principles, traditionally adapted from natural-area ecology, now increasingly emerge from the distinctive features of cities. Spatial patterns and flows, linking organisms, built structures, and the physical environment highlight a treasure chest of useful principles. This pioneering interdisciplinary book opens up frontiers of insight, as a valuable source and text for undergraduates, graduates, researchers, professionals, and others with a thirst for solutions to growing urban problems.

Urban Ecology: Science of Cities

Changes in rodent communities according to the landscape structure in an urban ecosystem

We analyzed the relation between rodent communities composition and diversity and the landscape structure in the city of Buenos Aires. Between October 2002 and December 2005 rodent samplings were conducted in a natural reserve, three parklands, three shantytowns and two industrial–residential neighborhoods. Landscape structure at each site was characterized by the proportion of the surface occupied by different land-cover types, and the proportion covered by buildings. We caught 413 rodents of the following species: the native Oligoryzomys flavescens, Deltamys kempi, Calomys musculinus and Cavia aperea; and the introduced Rattus norvegicus, R. rattus and Mus musculus. Native species were dominant in the natural reserve but were also present in parklands. R. rattus, R. norvegicus and/or M. musculus were the dominant species in parklands, shantytowns or industrial–residential neighborhoods. Differences in landscape structure contributed to explain differences in community composition. Diversity, richness and representation of native species decreased with increasing urbanization. Our findings may be useful for planning decisions for either conservation or pest control goals, based on the rodent community composition inferred from the landscape structure.

Changes in rodent communities according to the landscape structure in an urban ecosystem. Landsc Urban Plan

Assessing the sustainability of complex development processes requires multi-causal and integrated analyses. We develop a system-based methodology, rooted in interdisciplinary discussion and consensus building between 15 experts, to construct a multi-causal diagram which examines the sustainability of the Argentine Pampas´ process of agriculturization. The resulting diagram includes 25 factors and provides a big-picture of the multiple dimensions and interrelations affecting sustainability. According to this examination, the increasing concentration of production and the incorporation of technological innovations, triggered by economic and institutional factors, are the cause of environmental distresses and social changes, whose consequences for sustainability are still highly disputed. Nevertheless, the symptoms of both environmental and social unsustainability are more evident in the case of the extra-Pampean regions than in the Pampas. This suggests that the Pampean agriculture model should not be transferred to these regions without substantial modifications. The experts did not reach consensus on whether the agriculturization process is overall sustainable or unsustainable. Lack of consensus revolved mainly around opposing perspectives regarding the significance of the threats to environmental sustainability. The magnitude of socio-distributive unbalance and loss of rural jobs were also contentious. Yet, the paper shows how the exercise of building a joint causal diagram was undoubtedly helpful for linking piece-meal disciplinary facts, brought in from all fronts, into a comprehensive and coherent picture.

Multi-causal and integrated assessment of sustainability: the case of agriculturization in the Argentine Pampas

This paper describes the conflict between agriculture and urban development in the Pampa Ondulada, the eco-region where the city of Buenos Aires is located and which is one of the world’s richest a...

http://eau.sagepub.com/content/12/2/119.full.pdf+html

Urbanization and the consumption of fertile land and other ecological changes: the case of Buenos Aires

La ciudad de Buenos Aires, hoy convertida en megalopolis, esta asentada en la region del pais mas apta para la produccion agricola y ganadera: la pampa ondulada. En ella prosperaron tambien varios ecosistemas nativos que sucumbieron ante los avances agropecuario y urbanistico. La tierra que se urbaniza se pierde irrecuperablemente para otros usos.

R. R. Casas

Papers

Urbanization and the consumption of fertile land and other ecological changes: the case of Buenos Aires

Urbanización y consumo de tierra fértil