Biotechnologie et biomatériaux

Abstrait

Taxonomic diversity of woody species from 6 agroforestry systems in two sites with a different agricultural development in Nicaragua

Willan J Caicedo, Geovana Carreño - Rocabado, Jenny C Ordoñez, Bryan Finegan, Miguel Cifuentes and Eduardo Somarriba

The continued loss of biodiversity affects ecosystem functioning and reduces provision of key ecosystem services. With an ever increasing
land area devoted to agriculture, assessing the biodiversity value of different agricultural systems is becoming a priority issue to develop strategies
that maintain biodiversity in agricultural landscapes. This study was carried out in the central-northwest part of Nicaragua, in two sites in the
municipalities of El Tuma - La Dalia and Waslala -that exemplify different state of agricultural development- and 90 farms (n=45 per site). We
assessed the taxonomic diversity and composition of the woody species that are present in six land uses under agroforestry (coffee = CF, cocoa =
CC, live fences = CV, basic grains = GB, pastures = PA and patios = PT). An inventory of all woody species with a diameter > 9.9 cm was carried
out in 171.6 ha trough different sampling units according to the land uses assessed. The floristic similarity between the two study sites according to
the Bray – Curtis index was 60%, with 144 shared species. The species rarefaction curves showed higher total species richness in Waslala than in
La Dalia. In addition there were marked differences in species richness by land use in each of the sites evaluated, as well as significant differences
(p <0.01) for species richness ha-1 and for diversity indexes H ’and D’. Finally, we also found an interaction between agricultural land use and site
(analysis of variance p <0.05). Species richness at the landscape level is different both by sites and by land uses, while the species richness ha-1
and plot diversity was only different by land use, evidencing a change in the relative importance of land uses for diversity values in every place.