Biogeographic regionalization by spatial and environmental components: Numerical proposal

Abstract

Regionalization through the analysis of species groups offers important advantages in conservation biology, compared to the single taxon approach in areas of high species richness. We use a systematic framework for biogeographic regionalization at a regional scale based on species turnover and environmental drivers (climate variables and soil properties) mainly of herbaceous plant species richness. To identify phytogeographic regions in the Balsas Depression (BD), we use Asteraceae species, a family widely distributed in Seasonally Dry Tropical Forest (SDTF) and the most diverse of the vascular plants in Mexico. Occurrence records of 571 species were used to apply a quantitative analysis based on the species turnover, the rate of changes in their composition between sites (β-Simpson index) and the analysis of the identified environmental drivers. Also, the environmental predictors that influence species richness in the SDTF were determined with a redundancy analysis. We identified and named two phytogeographic districts within the SDTF of the BD (Upper Balsas and Lower Balsas). According to the multi-response permutation procedure, floristic composition of the two districts differs significantly, and the richness of exclusive species in Upper Balsas was higher (292 species) than in the Lower Balsas (32 species). The proportion of Mg and Ca in the soil and the precipitation of the driest three-month period were the environmental factors with greatest positive influence on species richness. The division of geographic districts subordinated to the province level, based on diverse families such as Asteraceae, proved to be appropriate to set up strategies for the conservation of the regional flora, since at this scale, variation in species richness is more evident. Our findings are consistent with a growing body of biogeographic literature that indicates that the identification of smaller biotic districts is more efficient for the conservation of biodiversity, particularly of endemic or rare plants, whose distribution responds more to microhabitats variation.

The role of ecological niche conservatism in the evolution of bird distributional patterns in Mesoamerican seasonally dry forests

“…Models of YP/MPS‐VS and MPS‐VS predicted similar suitable areas and showed similar temporal patterns. The contraction to the Balsas Basin (Flores‐Tolentino et al., 2021) during the LIG and MH and the latitudinal expansion to the Pacific Slope during the LGM and current time scenarios resemble the Interglacial Refugia Hypothesis, in which species contracted to warm/humid refugia during interglacials and expanded out during the cold/dry climate of the LGM (Contreras‐Negrete et al., 2021; Cornejo‐Romero et al., 2017). The inverse pattern was found for G. velox , A. rutila and F. cyanopygius , which roughly resembles the Glacial Refugia Hypothesis, in which species ranges contracted to refugia during the cold/dry glacial periods and later expanded following warm/humid interglacial periods (Avise & Walker, 1998; Cornejo‐Romero et al., 2017; Hewitt, 2000).…”

The use of ecological niche models improves biogeographic regionalization of the Balsas Depression, Mexico

“…ENM covers the limitations in the data available on species pres- The distribution analysis with the set of species analyzed identifies more regions than those reported in works carried out with the genus Bursera (Gámez et al, 2014) or Asteraceae (Flores-Tolentino et al, 2021). The study by Flores-Tolentino et al ( 2023)…”

“…In Mexico, the Balsas Depression (BD) has been used in various biogeographic regionalizations that include groups of fauna and flora (Flores-Tolentino et al, 2021). Based on the work of Smith (1941) with lizards of the genus Sceloporus or that of Gámez et al (2014) with trees of the genus Bursera, the province is divided into two districts: Balsas Superior and Balsas Inferior.…”

“…This is a result of, among other factors, its rugged orography and climatic heterogeneity (Fernández-Nava et al, 1998). Despite the importance of the BD, it has not been easy to circumscribe its geographical limits (Pérez-García et al, 2012;Flores-Tolentino et al, 2021, 2023. The importance of the regionalization of the BD lies mainly in the identification of important phytogeographic areas due to species sharing and richness of endemic species, in which further studies can be carried out aimed at their protection and management.…”

Georeferenced database and interactive online map of limnoterrestrial and freshwater Tardigrada from Central and South America

“…Murphy (2021) demonstrated several critical issues of this practice, which include overestimating endemism, underestimating biodiversity metrics (particularly endemism estimates), hindering understanding of biodiversity discontinuity across the world (especially true for measures containing species range size), and identifying hotspots. Thus, biogeographic regionalization is essential to comprehend ecological and evolutionary aspects of life (Crisp et al 2009, Holt et al 2013, Flores-Tolentino et al 2021.…”