Princípios da Agroecologia

Agricultura sustentável tem que considerar aspectos socioeconômicos e culturais dos grupos sociais implicados. Não basta proteger e melhorar o solo ou a produtividade agrícola se não resulta em melhorias nas condições de vida das pessoas envolvidas. Portanto, agricultura sustentável é um conceito que implica aspectos políticos e ideológicos que tem a ver com o conceito de cidadania e libertação dos esquemas de dominação impostos por setores de nossa própria sociedade e por interesses econômicos de grandes grupos, de modo que não se pode abordar o tema reduzindo outra vez as questões técnicas.

Francisco Roberto Caporal


"Muita gente pequena, em muitos lugares pequenos, fazendo coisas pequenas, mudarão a face da Terra". provérbio africano

Como os lobos mudam rios

Como se processa os animais que comemos

Rio Banabuiu


quarta-feira, 31 de outubro de 2012

Paleoecology and conservation

The latest paper of our research team is about the contribution of Quaternary paleoecology to nature conservation, and will be published soon in Quaternary Science Reviews as an invited review. This paper analyzes the role of paleoecology, as an ecological discipline, in the understanding of ecological processes ocurring at time scales beyond human observation capacity, and the application of this knowledge to nature conservation. Emphasis is on the responses of organisms and ecosystems to climate changes and fire, as two of the main current and near-future threats. The review is not limited to the usual theoretical aspects of the problem -which are also considered- but it is an attempt to show how paleoecology can contribute to address real environmental problems. At the end, several case studies from our own experience in the Neotropics are provided, in order to illustrate the usefulness of the main proposals discussed the general part. The paper is dedicated to Margaret Bryan Davis, one of the pioneers and more influential reserachers in the field. The summary of the paper is reproduced below.

Summary: Palaeoecology, as an ecological discipline, is able to provide relevant inputs for conservation science and ecosystem management, especially for issues involving long-term processes, such as ecological succession, migration, adaptation, microevolution, and extinction. This use of palaeoecology has been noted for several decades, and it has become widely accepted, especially in the frame of ongoing and near-future global warming and its potential biotic consequences. Selected palaeoecological insights of interest for conservation include the following: 1) species respond in an individualistic manner to environmental changes that lead to changes in community composition, suggesting that future ecosystems would have no modern analogues; 2) in the short-term, acclimation is more likely a response of species that are expected to persist in the face of global warming, but the possibility of evolutionary change linked to the existence of pre-adapted genomes cannot be dismissed; 3) species unable to acclimate or adapt to new conditions should migrate or become extinct, which has been observed in past records; 4) current extinction estimates for the near-future should be revised in light of palaeoecological information, which shows that spatial reorganisations and persistence in suitable microrefugia have been more common than extinction during the Quaternary; 5) biotic responses to environmental changes do not necessarily follow the rules of equilibrium dynamics but depend on complex and non-linear processes that lead to unexpected “surprises”, which are favoured by the occurrence of thresholds and amplifying positive feedbacks; 6) threshold responses can cause the movement of ecosystems among several potentially stable states depending on their resilience, or the persistence of transient states; 7) species and their communities have responded to environmental changes in a heterogeneous fashion according to the local and regional features, which is crucial for present and future management policies; 8) the global warming that occurred at the end of the Younger Drays cold reversal (ca. 13.0 to 11.5 cal kyr BP) took place at similar rates and magnitudes compared to the global warming projected for the 21st century, thus becoming a powerful past analogue for prediction modelling; 9) environmental changes have acted upon ecosystems in an indirect way by modifying human behaviour and activities that, in turn, have had the potential of changing the environment and enhancing the disturbance effects by synergistic processes involving positive feedbacks; 10) the collapse of past civilisations under climate stress has been chiefly the result of inadequate management procedures and weaknesses in social organisation, which would be a warning for the present uncontrolled growth of human population, the consequent overexploitation of natural resources, and the continuous increase of greenhouse-gas emissions; 11) the impact of fire as a decisive ecological agent has increased since the rise of humans, especially during the last millennia, but anthropic fires were not dominant over natural fires until the 19th century; 12) fire has been an essential element in the development and ecological dynamics of many ecosystems, and it has significantly affected the worldwide biome distribution; 13) climate-fire-human synergies that amplify the effects of climate, or fire alone, have been important in the shaping of modern landscapes. These general paleoecological observations and others that have emerged from case studies of particular problems can improve the preservation of biodiversity and ecosystem functions. Nature conservation requires the full consideration of palaeoecological knowledge in an ecological context, along with the synergistic cooperation of palaeoecologists with neoecologists, anthropologists, and conservation scientists.

Fire in the Gran Sabana (SE Venezuela)

Vegas-Vilarrúbia, T., Rull, V., Montoya, E. & Safont, E. 2011. Quaternary palaeoecology and nature conservation: a general review with some examples from the Neotropics. Quaternary Science Reviews, doi: 10.1016/j.quascirev.2011.05.006.

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Assine o Abaixo-Assinado virtual que pede o banimento dos agrotóxicos já proibidos em outros países do mundo e que circulam livremente no Brasil.

A Campanha tem o objetivo de alertar a população sobre os perigos dos agrotóxicos, pressionar governos e propor um modelo de agricultura saudável para todas e todos, baseado na agroecologia.

Assine já, pelo banimento dos banidos! Entre no link abaixo.