Resilience to salinity and drought in alien vs. native flora of Iran: a systematic review

Abstract

Background and aims

Stressful conditions in arid and semi-arid regions limit the range of plants that can thrive. These plants must possess traits that enable them to tolerate drought and salinity. This study aims to explore the complex interactions among various factors to identify the most drought- and salinity-tolerant alien and native plant species.

Methods

We collected data on germination tolerance to drought and salinity from 220 records from Iran. The selected documents contained information on X₅₀ (the level of drought or salinity stress that causes a 50 percent reduction in final seed germination). We screened the records based on their native range (native or alien) according to the recent alien plants̕ check-list of Iran. Additional information, such as the crops in which drought and salinity tolerance were examined, plant family, life cycle of the species, and ecological zones, was also included in the analysis. We employed artificial neural networks (ANN) to distinguish between alien and native species, using the aforementioned data as inputs.

Results

Alien and native species were classified with misclassification rates of 0, 0.023, and 0.01 during training, validation, and testing. We demonstrated that native species from Portulacaceae and Geraniaceae had higher drought tolerance, while the Protulacaceae, Amaranthaceae, and Fabaceae families showed the highest tolerance to salinity. Among alien plants, the Lamiaceae family had the highest drought and salinity tolerance. In general, the plant family, made the greatest contribution to both drought and salinity tolerance, followed by ecological zone for drought and life cycle for salinity. The alien plants with the highest drought tolerance were primarily concentrated in the Iranian-O-Turanian ecological zone. The Hircanian zone had a high number of alien plants, while the number in the Khaliji-O-Omanian zone was negligible. Overall, native species demonstrated significantly higher drought tolerance than alien species, but no significant difference in salinity tolerance was evident.

Conclusion

We show that an ANN can classify alien and native plants based on drought and salinity tolerance. Plant family traits, crop type, and life cycle strongly influence species classification. Native plants dominate in harsher environments, while alien species thrive in milder conditions. Understanding these differences can improve risk assessments and help prioritize harmful species, especially in the context of climate change.