Skip to main content

Currently Skimming:

5 Land-Use Change After Deforestation in Amazonia
Pages 94-120

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 94...
... Moran and Eduardo Brondizio This chapter describes a project that linked traditional social science and biological field methods with remotely sensed data to further understanding of how human decisions about land use have influenced both rates of deforestation and subsequent secondary successional rates of regrowth in Amazonia. The impetus for this project was a workshop held in 1987 that introduced ecological anthropologists to remotely sensed data as a tool in addressing substantive social science questions at a regional scale.
From page 95...
... Yet the large-scale work using remotely sensed data hardly mentioned secondary successional vegetation and rarely if ever suggested the significance of this vegetation to processes such as carbon sequestration, biodiversity, and land-cover dynamics.) The result of these reflections was the decision to craft a set of proposals based on the same technology as that used by the remote sensing communityLandsat Thematic Mapper (TM)
From page 96...
... THE VALUE ADDED OF SOCIAL SCIENTISTS' INTEREST IN REMOTE SENSING ANALYSIS Social scientists bring to the analysis of global change and its remote observation a concern about and an expertise in the behavior of people at the community and household levels and a desire to understand the human face behind the pixels (see Geoghegan et al., in this volume)
From page 97...
... By combining traditional ethnoecological field techniques that elicited culturally meaningful categories (A~caisal) with spatial distribution considerations elicited by the satellite data, it has been possible to distinguish between these two culturally and economically distinct vegetations (i.e., managed and unmanaged floodplain forest)
From page 98...
... One of the most important contributions social scientists can make to this type of research is to help construct data collection protocols that capture the types of socioeconomic data most closely related to land-use dynamics. It is all too common for those outside the social sciences to try to explain land-cover
From page 99...
... Soil fertility had seldom been related to or soil data collected in studies of forest ecology and succession (Buschbacher et al., 1988~. Since tracking of age classes of secondary succession and biomass accumulation in such vegetation had not been performed in Amazonia using Landsat TM (and had been unsuccessful using the Multispectral Scanner [MSS]
From page 100...
... For the selected locations, we seek available cloudfree images of the study areas; depending on availability, we also try to obtain a set of images providing data intervals within which the processes of change can be observed, at least one of which is coincident with our field research. These data are then georeferenced and registered, exploratory spectral analysis is carried out in small subsets representative of different patterns of land cover, and this analysis is then used to carry out unsupervised classification of land cover over the entire study area.
From page 101...
... Their discussion of the image provides an invaluable source of information about land-use and land-cover dynamics and makes sense out of the distribution of the different types of land cover encountered. In addition to the field-sampled plots, one or more members of the team collect "training samples" (i.e., visual observation of hundreds of locations)
From page 102...
... This data set is focused on secondary succession and land-use and land-cover change in five Amazonian regions distributed along a soil fertility gradient representing relatively nutrient-rich (eutrophic) to relatively nutrient-poor (oligotrophic)
From page 103...
... Ponta de Pedras, Marajo Island, Para, Brazil 3 Igarape-Agu, Bragantina, Para, Brazil 4 Tome-Agu, Para, Brazil 5 Yapu, Vaupes Basin, Colombia 103 FIGURE 5-2 Research sites in Amazonia of the Anthropological Center for Training and Research on Global Environmental Change (ACT) , Indiana University.
From page 104...
... A stand inventory table, including absolute and relative frequency, density, dominance, basal area, importance value, and stem and total height, is prepared for each of the inventoried sites. A soil fertility index summarizing differences among regions is used (Alvim, 1974~.
From page 105...
... Therefore, while Marajo and Bragantina offer typical examples of oxisols, Tome-A~cu presents a soil type closer to an ultisol. Differences in soil fertility are small but significant among the study regions.
From page 107...
... ~3 indice (all dephts) 1 1 2 all ~3 45 4 5 1 ALTAMIRA MARAJO BRAGANTINA TOME_ACU YAPU FIGURE 5-4 Soil fertility indexes for five research sites (pH + OM + P + K + Ca + Mg - All.
From page 108...
... The greater diversity of saplings and herbaceous vegetation in this region is closely associated with resprouting of a specific group of families and species that has made it possible for them to survive under this intensive land-use system (Denich, 1991; Vieira et al., 1996~. However, the relationships among soil fertility, fallow cycle, and indicator species are still unclear and will be the focus of attention in the near future.
From page 109...
... Basin-Wide Patterns of Rates of Regrowth: Defining Stages of Regrowth in Amazonia An important finding of this study is the definition of basin-wide stages of regrowth based on the analysis of average stand height and basal area of the study locations that correspond to distinctions derivable from spectral analysis of satellite data. While this finding may not seem to represent an important social science contribution, the detection of rates of regrowth illustrates the use of remote sensing to discriminate social phenomena, specifically land-use patterns, thus socializing the pixel (see Geoghegan et al., in this volume)
From page 110...
... This model of regrowth stages can be applied to the Amazon region if landuse intensity, landscape diversity, and soil fertility variables are taken into account at the regional and local levels. The proposed regrowth classes provide a baseline for remote sensing analysis and large-scale studies of land-use and deforestation dynamics.
From page 111...
... Understanding these structural/spectral relationships gives social scientists a powerful tool for studying land use and agricultural cycles of human populations. The structural parameters presented above allow one to discriminate with modest effort between areas recently and long abandoned, and to collect good-quality training samples for image-supervised classification (see Mausel et al., 1993, for a fuller discussion of spectral characteristics of vegetation types)
From page 112...
... The feedback from social science research and the incorporation of culturally meaningful categories are important contributions to the mapping of changes between land-cover classes and understanding of the driving forces of such changes. One of the important reasons for social scientists to play an increasing role in efforts to classify land uses with remotely sensed data is that in so doing they can begin to shift the applications of remote sensing from a mapping mode to one that seeks to explain social structures and processes land-use dynamics, the lag time between commodity price shifts and landscape transformations, the estimation of yield from noncereal and even agroforestry crops, and the internal structure of households as revealed by the behavioral outcomes of that structure that are visible in land-cover changes.
From page 113...
... Coarse scales tend to mask both environmental and human variabilityone of the main things threatened by environmental change. To understand human and biological diversity, we need instrumentation that is sensitive to these fine-scale patterns and permits the linkage of fine-scale field research to remotely sensed data (see Cowen and Jensen in this volume, who raise similar issues relevant to work in urban areas)
From page 114...
... Such software packages provide an ideal tool for training social scientists, since they allow more effort to be dedicated to image analysis and interpretation than to the learning process for the software itself. Many social scientists are reluctant to work with digital data because of the slow learning curve for many remote sensing and geographic information system (GIS)
From page 115...
... Cumulatively, our various studies have developed structural criteria that facilitate the application of these considerations in spectral analysis of satellite data for other Amazonian regions. The linking of remotely sensed data to traditional field methods in the social and biological sciences has permitted more thoughtful sampling over a larger region, addressing questions of decadal change that could not be examined through traditional methods alone.
From page 116...
... Perhaps more important to discussions of global environmental change are findings that show the large extent of carbon sequestration by secondary vegetation and its very high rate in the initial 10 years after abandonment, its spatial variability as a function of soil fertility, and the role of land use in this process (Randolph et al., 1996~. In documenting the role of soils we have also found
From page 117...
... In both of the above new efforts, remotely sensed data play a key role at every stage of the research from the exploration of types of land cover, to the sampling approach taken in the field work, to the interviews with land users, to the analysis of land-use changes in time and space. These plans suggest a productive collaboration among social scientists, biological scientists, and the remote sensing community for years to come.
From page 118...
... This synthesis table includes information such as average stand height and range of diameter at breast height for particular land-cover classes to facilitate discrimination of classes of interest. This guide is based on earlier field vegetation inventories carried out in the region, but it can also be based on existing studies carried out by others.
From page 119...
... Brondizio 1994 Discrimination between advanced secondary succession and mature forest near Altamira, Brazil, using Landsat TM data.
From page 120...
... 1996 Secondary Succession in the Brazilian Amazon: Investigation of Regional Differences in Forest Structure in Altamira and Bragantina, Para State. Honors thesis, Indiana University.


This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More information on Chapter Skim is available.