Landscapes Forest and Global Change - ESA - Escola Superior ...

F.M. Rabenilalana et al. 2010. Multi-temporal analysis of forest landscape fragmentation in the North East of Madagascar
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4. Discussion
The annual deforestation rate was estimated to be 5.25%. This is very high in comparison to the
national rate of 0.3 % (FAO, 2009). This means that the pressure on the forest in the area of
Manompana is extremely high. In this part of the country, the local population does not produce
enough rice to feed their family, there is a chronic shortage. The rice needs are merely satisfied
on an average of nine months per year. The rest of the year people resort to other products,
mainly cassava, yams and bananas, as it is often not possible to buy rice during this starvation
period. The development of irrigated rice production is hampered by various factors, such as
topographical, technical, socio economic and policy. Thus, to maximize production, slash and
burn agriculture has remained the main method of food production so far. Therefore, the
deforestation is continuously increasing for upland rice production and the landscape is
becoming progressively more fragmented. The land use change map and examination of the
driving variables of deforestation indicate that distance to topographic parameters and to paths
has the highest impact on forest fragmentation, followed by distance to villages, rivers and
streams. Topography is an important factor impacting fragmentation. Most likely, because local
people’s choice of land clearing is strongly related to it. For example, local people prefer areas
where slopes are not too steep and land less windy because of climate. Paths are the only way of
communication in inaccessible areas. Thus, to access a forestland, the local population opened
paths along the forest edge or in the forest itself.
The result from this study will be able to contribute to the objectives of conservation. Indeed, if
the variables remain more or less the same in the coming years, meaning that there is no
opening of new paths or migration (village), and pertinence area doesn’t change, so biodiversity
richness biodiversity is maintained.
References
Achard, F., Eva, H., Stibig, H.J., Mayaux, P., Gallego, T., Richards, J.P., Malingreau, J.P.,
2002. Determination of deforestation rates of the world’s humid tropical forests. Science,
297: 999-1002.
Agresti, A., 2002. Categorical Data Analysis, Second Edition. Wiley, New York, USA. 734 pp.
Andren, H., 1992. Corvid density and nest predation in relation to forest fragmentation: a
landscape perspective. Ecology, 73 (3):
Benitez-Malvido, J. and Martinez-Ramos, M., 2003. Impact of Forest Fragmentation on
Understory Plant Species Richness in Amazonia. Conservation Biology, 17: 389-400.
Collinge, S. K., 2009. Ecology of Fragmented Landscapes. Baltimore: Johns Hopkins
University Press.
Eastman, J. R., 2006. IDRISI Andes, Tutorial. Clark University. IDRISI, production, Worcester,
USA. 284pp.
Ewers, R. and Didham, R. K., 2006. Confounding factors in the detection of species responses
to habitat fragmentation. Biological Reviews, 18: 117-142.
Fahrig, L., 2003. Effects of habitat fragmentation on Biodiversity. Annual Review of Ecology,
Evolution and Systematics, 34: 487-515.
FAO, 2009. Situation des forêts du monde. Organisation des nations Unies pour l’Agriculture et
l’Agriculture. Viale delle Terme di Caracalla - 00153 Rome, Italie. 168pp.
Forman, R. T. T., and Godron, M., 1986. Landscape ecology. John Wiley & Sons, Nex York.
620pp.
Forman, R. T. T., 1995. Land mosaics: The ecology of landscapes and regions. Cambridge
University Press, Cambridge, UK.
Franklin, S., Stenhoise, G. B., Hansen, M., Popplewell, C. C., Dechka, J.A., Peddle, D.R., 2001.
An integrated decision tree approach (IDTA) to mapping landcover using satellite remote
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.