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The dry savannas of French Guiana are home to a specific suite of birds, including the Bearded tachuri, whose presence contributed to the classification of the site of Trou Poissons as an Important Bird Area. This small passerine has a highly localized and fragmented distribution range in South America. In French Guiana, it is mainly found on the last dry savannas grasses in relative good statut of conservation of the coastal strip (Sinnamary-Iracoubo). Classified as « Near Threatened » by BirdLife International (IUCN, 2008), it is threatened by the degradation of this habitat.
French Guiana’s coastal savannas constitute localized and limited open environments. With their numerous and characteristic species of fauna and flora, they are of high biodiversity value. Yet their accessibility is increasing the pressure linked to land use and agriculture. Their area is decreasing considerably due to a lack of knowledge of the important conservation issues and to inexistent management schemes. This singular habitat is disappearing to make way for agricultural land maintained using fertilizer and pesticides, quarries or land development projects. In a landscape occupied almost exclusively by forest, savannas constitute localized ecosystem. They cover less than 2% of the territory and are concentrated along the ancient coastal plain, mainly between Organabo in the west and Cayenne Island in the east. These are called coastal savannas and form an almost continuous series from Brazil to Venezuela.
The main threat to the species is the degradation of the savanna habitat. Depending on the site, these savannas are threatened by conversion into agricultural land for soybeans, Eucalyptus plantations (Brazil, Paraguay and Argentina), intensive grazing and uncontrolled slash and burn agriculture. The disappearance of the savannas would lead to the disappearance of the Bearded tachuri, a species restricted to Savanna habitat, as well as the associated suite of bird species and for which it serves as a potential umbrella species. Savannas are directly impacted by the human activities concentrated on the coast and by the population growth inherent to this territory. Their degradation is therefore the result of two major factors : a lack of ecological knowledge of these habitats and species, and the necessary of management methods to conserve them; and agricultural projects involving the use of fertilizers and seeds, with the risk of irreversible pollution and environmental damage. A more recent threat is the development of the species Acacia mangium (or Racosperma mangium), planted in forest habitats to restore gold mining sites, flourishes in open environments and is proving to be invasive, contributing to the degradation of savanna habitats.
First, a reference model of a well protected savanna will be constructed and indicator species identified. Since the Trou Poissons savanna is one of the best conserved in French Guiana, the habitats it contains will be characterized with the help of a botanical expert, and inventories will be carried out on these habitats in order to identify the associated suite of bird species. Complementary inventories of bird species will be conducted on three degraded savannas to validate the Bearded tachuri and other savanna species (Red list of the savannas of the Guianas region drawn up by WWF) as potential environmental indicators. In a second phase, the aim of the project is to identify management and restoration practices for dry savannas. The following will be tested:
A livestock breeder will make one of his savannas available for these tests. The tests on slash and burn practices will cover the extent, control of the anticipated path, the frequency and the seasonality of these practices. Their impact on the dynamics of the environment, the composition of the floristic suite and the maintenance of endangered and umbrella species such as the Bearded tachuri will be evaluated. Tests on Acacia mangium control will be based on mechanical, thermal and combined control and on the comparison of these methods according to their frequency and seasonality. The tests on restoration techniques for degraded savannas will be based on direct seeding and replanting and a combination of these two approaches.
A technical guide for management authorities and municipalities will present the most conclusive results and methodologies to enable the techniques to be reproduced. In addition, a pilot project to develop savanna eco-tourism will be carried out with the Conservatoire du Littoral, the Comité de Tourisme de la Guyane and the municipalities of Sinnamary and Iracoubo.