Background:

Succulents are characteristic species of dry ecosystems. Of the environmental characters of the site, the slopes are runoff areas and they tend to be even drier. On the slopes succulent species of economic and ecological importance are established.

Hypothesis:

There are no differences in the floristic composition and ecological attributes of succulents on the slopes of different orientation at the Yagul Natural Monument.

Data description:

density, coverage and frequency; edaphic variables.

Study site:

Yagul, Tlacolula, Oaxaca a 1,600 m asl. Geographical coordinates 16° 58’ 26” y 16° 55’ 56” N, 96° 28’ 17” y 96° 25’ 51” W.

Methods:

Calculation of importance values. Through multivariate methods the floristic similarity among slopes was compared, and topographic and edaphic variables related to the species distribution were analyzed.

Results:

The richness of succulents in Yagul was 21 species; those with the highest IVI were Opuntia pubescens present in all slope orientations, Hechtia pringlei on the north slope, O. pilifera in the south and Myrtillocactus schenckii on the east and west slopes. The north-facing slopes showed the greatest floristic difference from the rest. The most important edaphic variables in the distribution of populations were the content of organic matter and phosphorus.

Conclusions:

There is a difference in the floristic composition between slopes; the sites on the northern slope have the lowest richness and differ from the rest. The sites of the southern slope have a higher content of organic matter and phosphorus, which favors species such as Stenocereus treleasei and S. stellatus.

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