The cacti of the Tehuacán-Cuicatlán Valley, Mexico: estimation of the quality of sampling

Abstract

Cacti richness and endemism from Tehuacán-Cuicatlán Valley (VTC) is well known but the qualitysampling is not. The aim of this work was to describe the distribution of cacti species in the VTC and assess the qualitysampling. We generated a species richness map and estimated the distribution area for every species, with the aid ofquantitative biogeography techniques based on species incidence records within Operative Geographic Units (OGU).We used a grid of 159 OGUs (cells 5’ longitud x 5’ latitude). Cacti richness and quality sampling in each OGU wasassessed with the Chao2 non-parametric estimator. Results indicated: 1) high (63.4%) species concentration in thesubregion of Zapotitlán Valley; 2) a richness of 71 species in the VTC and a total estimated richness of 76 species;3) an adequate quality sampling (> 75%) in 53% (85 out of 159) of the total of OGU; and 4) a restricted distributionin 63.4% (45 out of 71) of species in at least less than 10% of VTC area.