Geography Conference Abstracts
College of Liberal Arts
1250 Bellflower Boulevard
California State University
Long Beach, CA 90840-1101 USA
Dr. Paul Laris
- "The biogeographical implications of indigenous fire regimes in the humanized savanna landscape of southern Mali" to the Association of American Geographers meeting in Chicago, March 2006.
- Savanna fires have long been considered a major force of vegetation change. Each year vast areas of the West African savanna-woodland are set ablaze for myriad reasons. Experimental studies on the long-term effects of repeated burning find that the trees/grass ratio is a function of the fire regime which gives rise to two competing theories: (i) repeated burning causes a decrease in the tree/grass ratio because fires progressively burn into densely wooded areas, killing trees on the margins and gradually shrinking the size and contiguity of the woodland patches; and (ii) repeated burning has a stabilizing effect on the tree/grass ratio because fires prevent new tree saplings from reaching maturity along the fringes of the forest patches. Few diachronic studies have examined the spatiotemporal pattern of the annual fires at a scale adequate for determining whether the fires are principal cause of woodland degradation. To address this issue, this study examines a series of burn-scar maps covering a 30 year period (1972-2003) for a wooded- savanna in southern Mali. A series of 17maps were generated from Landsat imagery. The maps were combined in a GIS to provide an estimate of the fire regime in terms of fire frequency, timing, and pattern. While gaps in the data preclude a definitive conclusion, preliminary results suggest that key woodland areas are "ringed" by less intense early dry season fires thereby preventing damage from late fires. The findings have implications for savanna fire management, biodiversity conservation, and savanna fire ecology.
Dr. Laris gave a paper:
- "Three views of a burned land: how issues of scale and narrative affect mapping and monitoring anthropogenic savanna fires in West Africa" to the Association of American Geographers meeting in Denver, April 2005.
- Multi-scale analysis is a cornerstone of political ecology research. It is often argued that an understanding of nature-society relationships requires "scaling up" from the local to the global to examine the forces shaping natural resource access, use, and transformation. Yet the ways in which scale is conceived and theorized by the natural and social sciences differs greatly reflecting the epistemological differences between the two research traditions. For example, biogeographical research takes its cue from the natural sciences and places the emphasis on selecting the appropriate, "operational" scale of analysis for the phenomenon in question because different processes operate at different scales. In contrast, many contemporary human geographers view scale as a social construction. The major constructivist approaches explore how specific scales come into existence for particular phenomena and how their relative importance changes over time. Taking the case of savanna fires in West Africa this paper examines 3 perspectives of the savanna fire problem in terms of these different conceptions of scale: the continental view derived from remotely sensed imagery and grounded in global change research, the colonial view with its origins in a regional narrative of savannization, and the patch-mosaic view rooted in landscape ecology.
Dr. Laris presented:
- "Patch Mosaic Burning: Exploring the Linkages between Human Practices and Biogeographical Theory" to the Association of American Geographers meeting in New Orleans, March 2003.
- There has been a gradual shift in recent years towards promoting a regime of small, fragmented or "patch-mosaic" fires in savanna and other wet/dry ecosystems. In theory patch mosaic burning increases the number of edges_boundaries of ecological areas_and reduces the potential for a large, destructive, fires creating a greater diversity of microhabitats. Biogeographical research finds that high spatial and temporal heterogeneity in the landscape is linked to high levels of biodiversity. Numerous scholars have argued that indigenous populations in the savanna and other wet/dry environments practiced patch-mosaic burning. In most cases the indigenous burning regime has been replaced through fire suppression policies or removal of the indigens. Indeed there is now a growing trend to reintroduce patch- mosaic burning in many areas. In large parts of the West African savanna, however, indigenous burning regimes remain predominant. This study finds that these burning practices continue to produce a patch-mosaic landscape despite persistent efforts by governments to suppress fire. The study documents the spatio-temporal pattern of burning for southern Mali by analyzing data generated from remotely sensed imagery, a survey of rural inhabitants, and forest service records. It finds some marked differences between the indigenous pattern of burning in Mali and the theoretical "patch-mosaic" regime described in the fire ecology literature. The implications of the findings for savanna ecology, fire management, and biodiversity are explored.
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Last revised: 01/10/06