Assessing climate impact: Distribution modeling and conservation of
Sesamum (Pedaliaceae) species
Abstract
Premise: Plants, particularly those with limited distribution ranges and
small population sizes, are expected to be severely impacted by changing
climatic conditions. Sesamum species are ideal for Species Distribution
Modeling (SDM) in the context of climate change due to their narrow
distribution ranges, agricultural and economic significance, sensitivity
and adaptability to environmental conditions, wide geographic range, and
potential to inform policy and adaptation strategies Methods: We used
Maximum Entropy (MaxEnt) Model to quantify global ecological niche
breadth of species in the genus Sesamum and to assess how bioclimatic
and soil heterogeneity indices impact the future (to the year 2080)
suitable distribution ranges of the genus Sesamum. We also quantified
which environmental variables contribute most to driving the patterns
and suitable geographical ranges for Sesamum. Results: Maxent models
accurately predicted suitable habitats for Sesamum species.
Precipitation patterns, especially seasonal extremes, were key
determinants of species distribution. Temperature also influenced
habitat suitability, with specific requirements varying among species.
These findings highlight the complex interplay between climate and
edaphic factors in shaping species distributions. Species with broader
niches have larger geographic ranges. However, future climate change is
predicted to reduce niche breadths for most species (74%), with some
facing substantial range contractions. In contrast, a few species (11%)
are projected to expand their ranges, while other species (15%) will
experience negligible impacts. Phylogenetic analysis did not reveal
significant patterns in extinction risk and niche breadth evolution.
Conclusion: This study highlights the vulnerability of Sesamum species
to climate change, with projected reductions in range sizes
necessitating urgent conservation efforts. Prioritizing species such as
S. forbesii and S. sesamoides, alongside targeted actions such as
habitat restoration and long-term monitoring, is crucial to prevent
population decline and potential extinction.