Assessing the Risk of Extinction of Vascular Plants Endemic to the Yucatán Peninsula Biotic Province by Means of Distributional Data

Abstract

An assessment of the extinction risk of the endemic plants from the Yucatán Peninsula Biotic Province (YPBP) was performed based on distributional data (B criteria of the IUCN) using the GeoCAT tool. The YPBP is located in southeastern Mexico and comprises the Mexican states of Campeche, Quintana Roo, and Yucatán, and the northernmost portion of Belize (districts of Belize, Corozal, and Orange Walk), as well as a portion of northern Guatemala (most of the department of Petén). An analysis of the YPBP flora identified 167 endemic taxa, 154 of which grow in at least one of the three Mexican states (Campeche, Quintana Roo, and/or Yucatán), whereas another 13 occur exclusively in Belize and/or Guatemala. Eighty-five are in some category of risk (50.9%): 17 taxa (10.18%) are categorized as Critically Endangered (CR), 40 (23.95%) as Endangered (EN), and 28 (16.77%) as Vulnerable (VU). Eighty-one (48.5%) species are not threatened: 12 (7.19%) as Near Threatened (NT) and 69 (41.32%) as Least Concern. A single species (0.6%) is considered Data Deficient (DD). The greatest number of endemic species and endemic threatened species inhabit dry and subhumid forests, and some inhabit semi-evergreen forests. The habits of endemic species and threatened endemic species are diverse, but trees, grasses, and shrubs predominate. The official system of protected natural areas (PNA) does not guarantee the conservation of all endemic species in the region. Ninety-eight (58.68%) of the endemic taxa have more than one population (record) within a PNA.

Biogeographical History of the Yucatan Peninsula Endemic Flora (Spermatophyta) from a Phylogenetic Perspective1

“…4A). Dictyanthus aeneus grows in the shady understory, while D. yucatanensis thrives in open environments, such as forest margins and along road edges (Carnevali, 2021b). However, the infrequent occurrence of natural hybrids between the two species (Carnevali, 2011) suggests that barriers to gene flow between them are still not well-established.…”

“…In the YPBP, many endemic species are not restricted to a single vegetation type but are widely distributed throughout the territory (Carnevali et al, 2021b). This suggests that environmental barriers have not been strong enough to promote diversification processes within the YPBP.…”

“…The flora of the YPBP currently faces serious anthropogenic threats from changes in land use due to urban and agricultural expansion, as well as from energy and tourism projects (Sánchez-Sánchez et al, 2015; Reyes-García et al, 2019). Approximately 51% of the endemic taxa are listed in a risk category, of which some 44% are listed as threatened or critically threatened (Carnevali et al, 2021b).…”

“…The search categories were Phylogenetic studies (including the terms phylogen*, monop*, systemat*, sistemat*, relationsh*, relacio*), Phylogeographic studies (phylogeog*, filogeog*), Phylogenomic analysis (phylogenom*, genome-scale, “plastid genome”), Diversity studies (diver*, geneti*, pop*, pobl*) and Biogeography (biogeog*). The endemic species list of Carnevali et al (2021b) was updated with the addition of taxa recently recognized as endemic (e.g., Echites yucatanensis Millsp. ex Standl.…”

“…and quasi-endemic species (8 spp.) (Carnevali et al, 2021b). Quasi-endemics are limited to the area of endemism but also reach the border or transition zones with adjacent biogeographical provinces or are represented by a few isolated populations beyond the boundaries and into neighboring provinces.…”