Thu, Aug 05, 2021:On Demand
Background/Question/Methods
The Colombian Andean basin is experiencing high and growing impacts from anthropic pressures including deforestation, oil and mineral extraction and water pollution. We examined patterns of spatial turnover and nestedness in the diverse but understudied assemblage of freshwater fishes of the eastern slope to inform conservation strategies aimed at preserving its unique ichthyofauna.
Presence and absence of 196 fish species from 183 sites (i.e. lagoons, rivers, streams) visited from 1971 to 2016 in the Cusiana River sub-basin, from Orinoco basin, were obtained from the metadata available in the Information System on Biodiversity of Colombia (SIB). Fish Collections reported in the metadata were visited and examined to verify the taxonomic, geographic and temporal accuracy of the reports We computed two family of dissimilarity indices, Sorensen and Jaccard, to quantify the spatial turnover and the nestedness components in four groups: Cusiana River basin (Overall species and sites), and three ecoregions classified accordinglyAbell et al (2008, Bioscience): Andean Region (7 species, 15 sites), Piedmont Region (96 species, 117 sites) and Llanos region (175 species, 51 sites).
Results/Conclusions We found that beta dissimilarity was driven mainly by turnover rather than nestedeness within each of the regions, however, the nestedness component also contributed significantly within the Andean region. The importance of differentiating the components of beta diversity is that they allow us to elucidate patterns of occurrence of the species and this helps to formulate the design of protected areas. The conservation strategies based on components of beta diversity are: if the process is nestedness, it is advisable to protect some areas that represent the highest species richness; if the process is spatial turnover, it is advisable to protect many areas with varied habitats. With the results obtained in this research, it will be possible to contribute to the improvement of the Cusiana River Basin Management and Planning (POMCA, for the acronym in Spanish) proposed by the governmental institutions and policy and decision-makers. In conclusion our results evidence that our study area is a hotspot of beta diversity and all ecoregions must be protected.
Results/Conclusions We found that beta dissimilarity was driven mainly by turnover rather than nestedeness within each of the regions, however, the nestedness component also contributed significantly within the Andean region. The importance of differentiating the components of beta diversity is that they allow us to elucidate patterns of occurrence of the species and this helps to formulate the design of protected areas. The conservation strategies based on components of beta diversity are: if the process is nestedness, it is advisable to protect some areas that represent the highest species richness; if the process is spatial turnover, it is advisable to protect many areas with varied habitats. With the results obtained in this research, it will be possible to contribute to the improvement of the Cusiana River Basin Management and Planning (POMCA, for the acronym in Spanish) proposed by the governmental institutions and policy and decision-makers. In conclusion our results evidence that our study area is a hotspot of beta diversity and all ecoregions must be protected.