Beta diversity and similarity among cactus assemblages in the Chihuahuan Desert

• Published in: Journal of arid environments Vol. 65; no. 4; pp. 513 - 528
• Main Authors: Goettsch, B., Hernández, H.M.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2006
• Subjects: Cactaceae; cacti and succulents; deserts; Jaccard's similarity index; Mexico; species diversity; Species turnover; Mexico; Species turnover; Mexico; Cactaceae; Jaccard's similarity index
• ISSN: 0140-1963; 1095-922X
• DOI: 10.1016/j.jaridenv.2005.08.008

We sampled the cactus species in 23 localities along a longitudinal transect in the southeastern segment of the Chihuahuan Desert. Using Wilson and Shmida's formula we calculated beta diversity values among contiguous and non-contiguous sites. As a complement, Jaccard's index of similarity was also calculated among all sites. A total of 61 species were found along the transect, although most tended to be infrequent, and only 27 surpassed the mean value of the frequencies (mean f = 28.3 % ). In most cases, relatively high to moderate β diversity values were obtained. The average value for all the site combinations was β = 0.52 (S.D.=±0.17, range=0.12–0.93). The highest similarity value was I S J = 0.79 , corresponding to two non-contiguous localities. The high diversity of cactus species in the study area may be explained, in part, by a relatively high to moderate level of turnover among the different species assemblages. However, β diversity is mainly a product of the intermittent pattern of spatial distribution of the cactus species in this region, rather than a real species turnover.