Species Distribution Models: Application to the Identification of Populations and Potential Distribution Areas of the Forage Plant Bituminaria bituminosa

The species Bituminaria bituminosa (L.) C.H. STIRT has been studied over the past two decades to be integrated as a forage crop in agro-silvo-pastoral systems due to its nutritional qualities and low water requirements (<200 mm). These efforts have led to the development of new varieties using genotypes from the Canary Islands. These varieties are expected to be utilized in mixed or monoculture systems, leveraging their drought tolerance to extend the availability of high-quality feed, thus reducing costs during the forage shortages of the summer season. The ability of Bituminaria to fulfill this role in Mediterranean basin farms will largely depend on its adaptation to environmental conditions.

This study aims to explore the circum-Mediterranean distribution of Bituminaria using Species Distribution Models (SDMs) and 33,132 occurrences from the GBIF platform on natural populations of the species. Bioclimatic, edaphic, geomorphological, and satellite-derived variables were used in model development through the biomod2 package in R, achieving ensemble model metrics with a mean True Skill Statistic (TSS) of 0.78. Eight clusters have been proposed to group occurrences based on the most important variables identified in the ensemble model, which also aids in identifying isolated populations or localized scenarios that may serve as a foundation for breeding programs aimed at improving specific traits. These results will contribute to a deeper understanding of the ecology, phenotypic plasticity, population dynamics, movement patterns, and evolutionary processes within the genus Bituminaria.