Abstract Detail

Floristics & Taxonomy

Rodríguez-Sánchez, Mariana [1], Ochoterena, Helga [2], Pisanty, Irene [3], Flores-Olvera, Hilda [4].

GYPSOPHILES OF CUATRO CIÉNEGAS, COAHUILA, MEXICO. Comparison of plant assemblages in patches with different gypsum content.

The most diverse assemblages of gypsophiles worldwide are established within the Chihuahuan Desert, along extensive gypsum outcrops that host many endemics, particularly within the Cuatro Ciénegas Basin (CCB) in Coahuila, Mexico. The CCB is an area characterized by a complex mosaic of soils with different gypsum contents. Despite the phylogenetic and ecological importance of these assemblages, more so given the different threats that they face, studies regarding patterns and processes that drive to specialization in gypsum environments are scarce. This study aims to compare floristic assemblages established on different gypsum landscapes within the CCB and to establish whether gypsum concentration plays a major role in their differentiation. To test this, ten 30x30 m plots on gypsum-rich sites and two on gypsum-poor sites were selected within the CCB and the contiguous La Virgen valley. Among the plots, gypsum concentrations varied from 2% to 98%. Each plot was divided into six 3x3 m subplots, and three 25 m transects were set. Species presence within the subplots and in contact with the transects were recorded, collected, and identified. Richness and Jaccard dissimilarity distances were determined, and assemblages grouping was detected through hierarchical clustering analysis. All plots included 98 identified species from 62 genera and 31 families, including several endemics to the Chihuahuan Desert or even the CCB, mostly from Caryophyllales. The most diverse families were Cactaceae, Asteraceae, and Amaranthaceae, and the genera with more species were Euphorbia, Agave, and Opuntia. Floristic assemblages were grouped into two main clusters, one including poor-gypsum sites and the other with gypsum-rich plots, which suggest a relevant roll of gypsum on the differentiation of assemblages. Nonetheless, gypsum-rich plots did not group in correlation with gypsum content. We concluded that the presence of gypsum is the first factor influencing the differentiation of floristic assemblages. However, after a certain concentration of gypsum is reached, floristic differences among assemblages are probably influenced, in addition to gypsum content, by the interaction of several factors, such as physiography, topography, different soil characteristics, and biotic interactions. Thus, we suggest that further studies should focus on such factors to disentangle the explanations for the establishment and evolution of such marvelous gypsum assemblages.

1 - Posgrado en Ciencias Biológicas, UNAM, Mexico City, 04510, Mexico
2 - Instituto de Biología, UNAM, Departamento de Botánica, Apartado Postal 70-233, Mexico City, 04510, México
3 - Facultad de Ciencias, UNAM, Departamento de Ecología y Recursos Naturales, Mexico City, 04510, Mexico
4 - Instituto de Biología, UNAM, Departamento de Botánica, Apartado Postal 70-233, Mexico City, 04510, Mexico

Keywords:
Caryophyllales
Chihuahuan Desert
endemism
Plant diversity
Plant ecology.

Presentation Type: Poster
Session: P2, Floristics & Taxonomy Posters
Location: Virtual/Virtual
Date: Tuesday, July 20th, 2021
Time: 5:00 PM(EDT)
Number: P2FT004
Abstract ID:194
Candidate for Awards:None