Changes in Size of Deforested Patches in the Brazilian Amazon

• Published in: Conservation biology 2012-10, Vol.26 (5), p.932-937
• Main Authors: ROSA, ISABEL M. D., SOUZA, CARLOS, EWERS, ROBERT M.
• Format: Article
• Language: English
• Subjects: Agriculture - classification; Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Brazil; Cattle ranching; Conservation biology; conservation effectiveness; Conservation of Natural Resources - methods; Conservation, protection and management of environment and wildlife; deforestación tropical; Deforestation; dinámica espacial; dinámica temporal; distribución de tamaños; efectividad de la conservación; Environment; Environmental Policy; Forest conservation; Fundamental and applied biological sciences. Psychology; General aspects; Geographic Mapping; Government Regulation; Land management; Land ownership; Old growth forests; Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Property rights; Research Note; Seasons; Size distribution; Spacecraft; spatial dynamics; temporal dynamics; tropical deforestation; Tropical rain forests
• ISSN: 0888-8892; 1523-1739
• DOI: 10.1111/j.1523-1739.2012.01901.x

Different deforestation agents, such as small farmers and large agricultural businesses, create different spatial patterns of deforestation. We analyzed the proportion of deforestation associated with different-sized clearings in the Brazilian Amazon from 2002 through 2009. We used annual deforestation maps to determine total area deforested and the size distribution of deforested patches per year. The size distribution of deforested areas changed over time in a consistent, directional manner. Large clearings (> 1000 ha) comprised progressively smaller amounts of total annual deforestation. The number of smaller clearings (6.25—50.00 ha) remained unchanged over time. Small clearings accounted for 73% of all deforestation in 2009, up from 30% in 2002, whereas the proportion of deforestation attributable to large clearings decreased from 13% to 3% between 2002 and 2009. Large clearings were concentrated in Mato Grosso, but also occurred in eastern Pará and in Rondônia. In 2002 large clearings accounted for 17%, 15%, and 10% of all deforestation in Mato Grosso, Pará, and Rondônia, respectively. Even in these states, where there is a highly developed agricultural business dominated by soybean production and cattle ranching, the proportional contribution of large clearings to total deforestation declined. By 2009 large clearings accounted for 2.5%, 3.5%, and 1% of all deforestation in Mato Grosso, Pará, and Rondônia, respectively. These changes in deforestation patch size are coincident with the implementation of new conservation policies by the Brazilian government, which suggests that these policies are not effectively reducing the number of small clearings in primary forest, whether these are caused by large landholders or smallholders, but have been more effective at reducing the frequency of larger clearings. Diferentes agentes de deforestación, como campesinos y negocios agrícolas, crean diferentes patrones espaciales de deforestación. Analizamos la proporción de deforestación asociada con claros de diferentes tamaños en la Amazonía brasileña entre 2002 y 2009. Utilizamos mapas de deforestación anual para determinar el área total deforestada y la distribución de tamaños de parches deforestados por año. La distribución de tamaños de áreas deforestadas cambió de manera consistente y direccional. Los claros extensos (> 1000 ha) progresivamente abarcaron cantidades menores de deforestación anual total. El número de claros pequeños (6.25—50.00ha) permanecieron