Biodiversity estimators as conservation priority: the experience from benthic fauna from the Yungas basin.

MESA, L. M., FERNÁNDEZ H. R., DOMINGUEZ, E.

Buenos Aires

Congreso; Environmental change and rational water use.; 2005

Comisión para la sustentabilidad del agua de la Unión Geográfica Internacional (UGI).

The International Conference on “Biodiversity: Science and Governance” in Paris (February 2005) recalls the commitment of governments to the global target of significantly reduce the rate of biodiversity loss by 2010 as a fundamental condition for sustainable development. They recognized that Biodiversity is a vital and poorly appreciated resource for all humankind that underpins the achievement of the Millennium Development Goals. Also, biodiversity is being irreversibly destroyed by human activities at an unprecedented rate, that demands urgent and significant action to conserve, sustainable use and equitably share the benefits of biodiversity. Because of its broad scope and multidimensional nature, biodiversity has the potential to serve a unifying role by providing a basis for effective management and restoration initiatives. Among aquatic organisms, invertebrates are frequently omitted from biodiversity analysis for conservation priorities. We were committed  with the aquatic macroinvertebrate fauna from the NW  Argentina Yungas focusing our studies in richness estimations and their possible use for conservation. This ecoregion includes 3 900 000 ha, between 22º and 28º S. This is one of the biological richest area in Argentina, included in a Tropical Andes hot-spot. To estimate the richness of four sub-basins of Sali-Dulce basin we used a data base (>2,500 inputs) of  macroinvertebrates from this region. Among these, 960 data of 6 orders of arthropods were chosen. We used Coleman, ICE and Jacknife estimators of richness, focusing in curves and in richness estimation for further comparisons. One basin was very well sampled, considering no gap existence between estimators and observed curves. On the same basis, two other were undersampled, and the last one was intermediate.  This situation is observed when data come from undersampled basins. Also, the Jacknife estimator subsample shows no differences (p<0.05) between the two Northernmost basins (>70 taxa each one). On the other hand, the Southernmost basins compared presented lower richness (p>0.05). The comparation of the estimators of the two well sampled basins, allowed us to determine that one of  them presents a higher richness, and suggest it is a potential source of new species. This could represent a higher biodiversity conservation potential. Due to the size and conservation of the two undersampled basins, they are potentially richer than the well-sampled ones. Which would be the picture if the four  basins  would be equally known? It is necessary to have an accurate estimation of the richness of the considered basins before a conservation decisions can be taken. A database that integrates the systematic, ecological and geographical information represents a tool that provided the basis to logically compare the conservation potential of these different basins.