Large area mapping of land‐cover change in Rondônia using multitemporal spectral mixture analysis and decision tree classifiers

Abstract

[1] We describe spatiotemporal variation in land cover over 80,000 km 2 in central Rondônia. We use a multistage process to map primary forest, pasture, second growth, urban, rock/savanna, and water using 33 Landsat scenes acquired over three contiguous areas between 1975 and 1999. Accuracy of the 1999 classified maps was assessed as exceeding 85% based on digital airborne videography. Rondônia is highly fragmented, in which forests outside of restricted areas consist of numerous, small irregular patches. Pastures in Rondônia persist over many years and are not typically abandoned to second growth, which when present rarely remains unchanged longer than 8 years. Within the state, annual deforestation rates, pasture area, and ratio of second growth to cleared area varied spatially. Highest initial deforestation rates occurred in the southeast (Luiza), at over 2%, increasing to 3% by the late 1990s. In this area, the percentage of cleared land in second growth averaged 18% and few pastures were abandoned. In central Rondônia (Ji-Paraná), deforestation rates rose from 1.2% between 1978 and 1986 to a high of 4.2% in 1999. In the northwest (Ariquemes), initial deforestation rates were lowest at 0.5% but rose substantially in the late 1990s, peaking at 3% in 1998. The ratio of second growth to cleared area was more than double the ratio in Luiza and few pastures remained unchanged beyond 8 years. Land clearing was most intense close to the major highway, BR364, except in Ariquemes. Intense forest clearing extended at least 50 km along the margins of BR364 in Ji-Paraná and Luiza. Spatial differences in land use are hypothesized to result from a combination of economic factors and soil fertility.

Seasonal variation of ozone deposition to a tropical rain forest in southwest Amazonia

“…Kirkman et al, 2002). The average deforestation rate in central Rondônia increased between 1990 and 1999 from ∼1.2% per year to ∼3.4% per year (Roberts et al, 2002). The LBA-EUSTACH 1 and 2 experiments offered the unique possibility to establish a direct and comprehensive comparison of O 3 uptake by pasture and rain forest, since Kirkman et al (2002) measured O 3 deposition at a cattle pasture site simultaneously to the forest work during both campaigns, using a combination of soil chamber and micrometeorological profile techniques.…”

Using fuzzy cognitive maps to describe current system dynamics and develop land cover scenarios: a case study in the Brazilian Amazon

“…Medium (250-1000 ha) and big farms (>1000 ha) occupy areas outside the official settlements, but land aggregation is often observed in older settlements (Coy 1987;Millikan 1992;Pedlowski, Dale, Matricardi, and da Silva 1997;Escada 2003). Soil fertility is an important determinant when hardly any forest remnants are left (Roberts et al 2002;Soler and Verburg 2010). Rainfall determines deforestation at the regional scale as more pronounced dry seasons increase agro-pasture productivity (Schneider, Arima, Veríssimo, Barreto, and Souza 2000;Sombroek 2001).…”

Estimativa de área de vegetação secundária na Amazônia Legal Brasileira

“…De acordo com alguns estudos encontrados na literatura ( Odum, 1969;Moran et al, 2000;Nelson et al, 2000;Roberts et al, 2002;Neeff et al, 2006) O grande extensão da AML faz com que esta região seja um mosaico de muitos ambientes, não só físicos, mas também histórico-culturais e sócio-econômicos (Hurtienne, 2005). Assim, buscando representar a diversidade de formas de uso da terra e os agentes associados a esses usos, foi utilizado o mapa de estrutura agrária da Amazônia Legal (IBGE, 2007).…”

“…Os intervalos para o fatiamento foram definidos a partir de valores de nível de cinza que correspondiam a essa cobertura vegetal. Conforme pode ser encontrado em Shimabukuro e Smith (1991); Hall et al, (1995); Bernardes (1998); Roberts et al (2002); Lu et al (2003bLu et al ( , 2004aLu et al ( , 2004b; as área ocupadas por formações florestadas (ainda que em regeneração inicial) apresentam valores de nível de cinza expressivamente maiores que as áreas desflorestadas na imagem fração vegetação e, valores menores na fração solo.…”

“…Diversos autores mapearam em escala local a ocorrência de vegetação secundária e encontraram relações desta com os ambientes físico e sócio-econômico da região (Alves & Skole 1996;Nelson et al, 2000;Steininger, 2000;Roberts et al, 2002;Alves et al, 2003;Lu et al, 2003a;Espírito-Santo et al, 2005;). Estimativas do total de área de vegetação secundária na AML foram realizadas através de métodos amostrais, considerando quase sempre um pequeno número de amostras, ou por medidas com base em dados de sensoriamento remoto de baixa resolução.…”