A Change in Conservation Status of Pachyphytum caesium (Crassulaceae), a Threatened Species from Central Mexico Based on Genetic Studies
by
, , , , , and
Tania Martínez-León
1, 
Ricardo Clark-Tapia
1,
Jorge E. Campos
2,
Luz Isela Peinado-Guevara
3,
Samuel Campista-León
3,
Francisco Molina-Freaner
4,
Nelly Pacheco-Cruz
2,
Gabriel González-Adame
1,
Juan José Von Thaden Ugalde
1 and
Cecilia Alfonso-Corrado
1,* 1
Instituto de Estudios Ambientales, Universidad de la Sierra Juárez, Avenida Universidad S/N, Ixtlán de Juárez, Oaxaca 68725, Mexico
2
Unidad de Biotecnología y Prototipos, Facultad de Estudios Superiores de Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios 1, Los Reyes Iztacala, Tlaneplantla 54090, Mexico
3
Laboratorio de Microbiología y Biología Aplicada, Facultad de Biología, Universidad Autónoma de Sinaloa, Av. Universitarios, S/N, Ciudad Universitaria, Culiacán Rosales 80013, Mexico
4
Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Hermosillo 83250, Mexico
*
Author to whom correspondence should be addressed.
Biology 2022, 11(3), 379; https://doi.org/10.3390/biology11030379
Submission received: 8 January 2022
/
Revised: 19 February 2022
/
Accepted: 25 February 2022
/
Published: 27 February 2022
Simple Summary
Species decline has accelerated in recent decades, with rare species often being the first to go extinct, mainly due to low population sizes. This study worked with Pachyphytum cesium (Crassulaceae), an endemic species from central Mexico threatened by human activities and climate change. To increase our knowledge of the species, we analyze the diversity and genetic structure of all known populations of P. caesium to change their current genetic status and propose conservation strategies. The results indicate that this species presents low to moderate levels of genetic diversity and incipiently structured populations due to low genetic flow. We found that genetic parameters are essential to the conservation strategies and status vulnerability reclassification. Based on our results, we propose reclassifying the conservation status of the species in danger of extinction; hence a series of conservation strategies are provided to prevent its disappearance.
Abstract
Genetic studies in rare species are important to determine their patterns of genetic diversity among populations and implement conservation plans aimed to reduce extinction risks. Pachyphytum caesium is an endemic species with extremely small populations in central Mexico. This work analyzes the diversity and genetic structure of Pachyphytum cesium (Crassulaceae) to change the conservation status and propose conservation strategies. Twelve dominant ISSR markers were used to describe the genetic diversity of all known populations. Additionally, we carried out two simulations to explore how the loss of individuals or the local populations extinction affect the genetics parameters of the species. The average results indicated moderate levels of genetic diversity (number of alleles = 89.7 ± 3.9, expected heterozygosity = 0.212 ± 0.0, and percentage of polymorphic loci = 56.1 ± 3.9), parameters that decreased significantly when simulations were performed in P. caesium. Additionally, a genetic structure of the populations was found with low gene flow (Nm = 0.92). Genetic parameters are negatively affected by the loss of individuals and the local extinction of populations. Based on our results, we propose to reclassify the conservation status of the species in danger of extinction, hence a series of conservation strategies are provided to prevent its disappearance.
