Current and Future Potential Distribution of the Xerophytic Shrub Candelilla (Euphorbia antisyphilitica) under Two Climate Change Scenarios

Abstract

Candelilla (Euphorbia antisyphilitica Zucc.) is a shrub species distributed throughout the Chihuahuan Desert in northern Mexico and southern of the United States of America. Candelilla has an economic importance due to natural wax it produces. The economic importance and the intense harvest of the wax from candelilla seems to gradually reduce the natural populations of this species. The essence of this research was to project the potential distribution of candelilla populations under different climate change scenarios in its natural distribution area in North America. We created a spatial database with points of candelilla presence, according to the Global Biodiversity Information Facility (GBIF). A spatial analysis to predict the potential distribution of the species using Maxent software was performed. Thirteen of 19 variables from the WorldClim database were used for two scenarios of representative concentration pathways (RCPs) (4.5 as a conservative and 8.5 as extreme). We used climate projections from three global climate models (GCMs) (Max Planck institute, the Geophysical Fluid Dynamics Laboratory and the Met Office Hadley), each simulating the two scenarios. The final predicted distribution areas were classified in five on-site possible candelilla habitat suitability categories: none (< 19%), low (20–38%), medium (39–57%), high (58–76%) and very high (> 77%). According to the area under the curve (0.970), the models and scenarios used showed an adequate fit to project the current and future distribution of candelilla. The variable that contributed the most in the three GCMs and the two RCPs was the mean temperature of the coldest quarter with an influence of 45.7% (Jackknife test). The candelilla’s distribution area for North America was predicted as approximately 19.1 million hectares under the current conditions for the high habitat suitability; however, the projection for the next fifty years is not promising because the GCMs projected a reduction of more than 6.9 million hectares using either the conservative or extreme scenarios. The results are useful for conservation of the species in the area with vulnerable wild populations, as well as for the selection of new sites suitable for the species growth and cultivation while facing climate change.

Predicting Climate Change Impacts on Candelilla (Euphorbia antisyphilitica Zucc.) for Mexico: An Approach for Mexico’s Primary Harvest Area

“…In Mexico, several studies have been developed to model the distribution of species under current climate conditions and for climate change scenarios [18,39,49,50]. The reduction in area due to the effect of climate change in candelilla in Mexico presents a similar behavior at the national level [51]. Coahuila is one of the states with the greatest decrease in area [52], a situation that highlights the importance of developing predictive models for the presence of candelilla in the state.…”

“…However, without controlled management, harvesting candelilla could lead to a considerable decline in the species [54]. Previous models of candelilla distribution in Mexico have been developed using climatic variables [51,55], or only with edaphological and terrain variables [46].…”

Impact of climate change on Asiatic black bear (Ursus thibetanus) and its autumn diet in the northern highlands of Pakistan

“…The average global temperature is expected to increase by up to 0.9–2.0℃ under RCP4.5, whereas the average global temperature is projected to increase by up to 1.4–2.6℃ under RCP8.5 (IPCC, 2013; UNFCCC, 2015). For future projections, we used HadGEM2‐AO (Met Office Hadley Center for atmosphere–ocean coupled climate model) as earlier studies showed this model best fit to our study area (Dai et al, 2021; Raman et al, 2020; Vargas‐Piedra et al, 2020; Wei et al, 2019). We downloaded the elevation data (at 1 km resolution) from GTOPO30 (https://lta.cr.usgs.gov/GMTED2010; Danielson & Gesch, 2011) and extracted the terrain roughness index (TII), aspect, and slope from it.…”

Modelado actual y futuro de la idoneidad de hábitat el ahuehuete ( Taxodium mucronatum Ten.): una propuesta para conservación en México

“…Los resultados obtenidos por los MCG, muestran tendencias similares a los de Martínez-Sifuentes et al (2020), donde encontraron reducciones de nicho ecológico para Pinus greggii Engelm de -9.5 %, con el modelo HadGEM2-ES bajo dos escenarios de cambio climático. Con respecto al modelo MPIESM-LR, el área potencial ante el cambio climático resultó menor, en comparación al modelo HadGEM2-ES, comportamiento que se ha evidenciado en otros estudios (Vargas-Piedra et al 2020).…”