Répartition des oiseaux dans le secteur forestier du canal de Panama : analyse et perspectives
|Advisor:||Desrochers, André; Robinson, Douglas|
|Abstract:||In this study, I examined the biogeography of avian species richness in fragmented tropical forests in order to understand and predict the effect of habitat loss and fragmentation on avian diversity in endangered forested landscapes near the Panama Canal. To reach this goal, I used the species-area relationship (SAR), a commonly used tool of Conservation Biology. However, the model I employed here differed from the standard SAR since it added the effect of non-random distribution patterns of species richness, and the non-random patterns of habitat loss, both previously neglected. In this study, I show that neither pattern was random. Species richness increased gradually from the dry seasonal forests of the Pacific coast to the humid evergreen forests of the Atlantic coast. Richness was higher in intact mature humid forests with higher vegetation diversity, and in rugged topography (which supports the habitat heterogeneity hypothesis); it also followed area (in larger and continuous tracts of forests). Similarly, habitat loss happened according to two predictable socio-economic patterns: urbanization or conversion to agriculture. Habitat loss scenarios were derived from the strongest factors (biophysical or socio-economic). Owing to the presence of two major growing cities in our study area, most habitat loss is expected to occur following urbanization. Unprotected forests in proximity of urbanized areas, main highways or affluent populations may be in immediate danger of conversion. The species-area relationship used in this study, which included the distribution patterns of richness and the habitat loss scenarios, yielded more dramatic and realistic results, compared to the standard SAR. The model predicted a drastic decline in forest bird species richness following the loss of only 24 % of actual forests remaining, a phenomenon called fragmentation threshold. This result alone may have strong repercussions on conservation discussions in the Panama Canal region and other endangered landscapes in the tropics. The use of this “improved” SAR model in making projections of species loss following habitat loss in the tropics represent a tool that might be extremely useful in conservation since it takes into account non-negligible aspects previously omitted.|
|Document Type:||Thèse de doctorat|
|Open Access Date:||13 April 2018|
|Collection:||Thèses et mémoires|
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