Adaptive fitness of Sapindus emarginatus Vahl populations towards future climatic regimes and the limiting factors of its distribution

Abstract

Sapindus emarginatus Vahl (Sapindaceae) also known as 'Indian Soap nut' is significantly important for saponin content in its fruits. However, its current population in India is heavily fragmented due to a lack of sustainable harvesting practices. Moreover, changing climatic regimes may further limit its distribution and possibly compromise the survival of the species in nature. The aim of the present study was to: predict the future distribution range of S. emarginatus; identify the bioclimatic variables limiting this distribution and to evaluate its adaptive fitness and genomic resilience towards these variables. To determine future species distribution range and identify limiting bioclimatic variables, we applied two different ecological niche models (ENMs; BioClim and MaxEnt) on real occurrence data (n = 88 locations). The adaptive fitness of the species was evaluated by quantifying the genetic variability with AFLP markers and marker-environmental associations, using AFLP-associated Bayesian statistics. We found 77% overlap between the baseline (2030) and predicted (2100) species distribution ranges, which were primarily determined by maximum temperature (T MAX) and mean annual precipitation (MAP). the t MAX and MAP contributed 43.1% and 27.1%, respectively to ENM model prediction. Furthermore, AFLP loci significantly associated with bioclimatic variables, and T MAX and MAP represent the lowest proportion (6.15%), confirming to the severe response of the species genome towards these variables. Nevertheless, the very low Linkage disequilibrium (LD) in these loci (4.54%) suggests that the current sensitivity to T MAX and MAP is subject to change during recombination. Moreover, a combination of high heterozygosity (0.40-0.43) and high within-population variability (91.63 ± 0.31%) confirmed high adaptive fitness to maintain reproductive success. Therefore, the current populations of S. emarginatus have substantial genomic resilience towards future climate change, albeit significant conservation efforts (including mass multiplication) are warranted to avoid future deleterious impacts of inbreeding depression on the fragmented populations. Sapindus emarginatus Vahl (Sapindaceae) also known as 'Indian 'Soap nut' is a tree species native to Indian sub-continent. In India, it is considered to be originated in the Western-Ghats and later extended up to the West-Central-North Indian biogeographical regions 1. The species is of substantial importance for global trade in soap and perfumery industries due to the oil and saponin content obtained from its leaves, fruits and seeds. The global trade of saponin from all plant sources is expected to grow up to 970 million US$ in 2023, from 950 million US$ in 2017 2. India exports approximately 63,368 kg/year of saponin extract obtained from all plant sources to different countries 3. The exact contribution of S. emarginatus to the global saponin market is unclear, but probably substantial as the species is widely used traditionally at Indian homes as detergent to wash precious ...

Distinct Ecological Adaptations and Habitat Responses to Future Climate Change in Three East and Southeast Asian Sapindus Species

“…Based on the genetic structure and geographical variation of Sapindus germplasms, Sun (Sun et al, 2018) found that areas of high altitudes and low minimum temperatures are suitable for the growth of S. delavayi. Ashish Kumar Pal (Pal et al, 2020) found that maximum temperature and annual precipitation were the most critical environmental factors determining the distribution of suitable habitats for S. emarginatus through the MaxEnt model. These ndings also demonstrate that precipitation is a prerequisite for suitable habitat distribution of Sapindus, and that S. emarginatus similarly diverges into signi cantly different ecological suitability.…”

“…Zhang et al (Zhang, Jing, Li, Liu, & Fang, 2019) and Peng et al (Peng et al, 2019) explored suitable habitats for Cinnamomum camphora and Paeonia ostia under current and future climate conditions, respectively, using ecological niche models and offered suggestions for their respective targeted collection and preservation. Ashish (Pal, Vaishnav, Meena, Pandey, & Singh, 2020) also simulated the adaptability and limiting factors of Sapindus emarginatus Vahl in the face of future climate regimes through two ecological niche models. Therefore, ecological niche model appear one of the optimal solutions to establishing how species will adapt to future climate scenarios.…”

Predicting the potential global distribution of Sapindus mukorossi under climate change based on MaxEnt modelling

“…Currently, S. mukorossi saponins have outstanding market benefits. India exports approximately 63,368 kg of saponin extract every year, and the total global saponin trade value is expected to reach US$970 million in 2023 (Kumar Pal et al 2020). With the reduction of petroleum reserves, biodiesel will become the main substitute for nonrenewable fossil fuels globally (Chakraborty and Baruah 2013), and the S. mukorossi biomass energy industry is also gradually developing.…”