Modeling the Distribution of Wild Cotton Gossypium aridum in Mexico Using Flowering Growing Degree Days and Annual Available Soil Water

Abstract

Climate change is expected to alter species distribution and habitat composition, with wild species being particularly vulnerable. Gossypium aridum, a wild cotton species in Mexico, has shown a decrease in habitat extent and population; however, the data are not precise. The objectives of this study are: (1) to develop a distribution model of G. aridum in Mexico, (2) to identify areas with environmental conditions similar to where the species currently maintains populations, and (3) to determine which variable, flowering growing degree days (FGDD) or annual available soil water (AASW, mm year−1), has greater influence on the distribution of the species. Geographic information system (GIS) software was used with datasets from two databases in Mexico that were partitioned for site characterization, model construction, calibration, validation, and sensitivity analysis. The range of 330–860 FGDD and 4–110 mm year−1 AASW best described the species habitat, according to results of seven precision and accuracy statistical tests. The model identified geographic regions throughout the country with similar conditions as the locations where the species has been observed, including some where no collections have not yet been registered in Mexican databases. FGDD, rather than AASW, showed greater influence on the distribution of the species. The generated information can be used to guide collection expeditions for G. aridum and to study climatic impact on species distribution. The approach using FGDD and AASW can be used in the modeling of wild cotton species that are valuable natural resources for crop improvement.

Loss and Gain in Potential Distribution of Threatened Wild Cotton Gossypium thurberi in Mexico under Future Climate

“…Some studies have demonstrated good predictive ability even with only three variables [67]. For this study, we considered the following variables because of their importance to the cotton plant [2,15,[68][69][70][71]: annual available soil water (mm year −1 , AASW), Flowering Growing Degree Days (FGDD), absolute minimum temperature ( • C, Tminabs), and altitude (amsl, ALT).…”

“…Flowering Growing Degree Days: the variable Growing Degree Days (GDD), also known as Heat Units (HUs) or thermal time, reflects the relationship between growth rate and temperature and refers to the specific amount of heat units that plants require to develop from one stage of development to another [15,[77][78][79][80]. In the present study, we considered Flowering Growing Degree Days (FGDD), which refers to the necessary GDD to cover the flowering phase, the prime physiological stage of the cotton plant that determines the final productivity [2,71]. It is calculated as follows:…”