干旱区生态环境知识资源中心

The inland vegetation of saline patches in the Cholistan desert faces extreme environmental conditions including predominantly salt stress and limited resource availability. Changes in the salinity gradients may lead to gradual variation in response of individual plant species that ultimately affect community structure and composition. The present study was conducted to determine spatial distribution of individual species along a salinity gradient in the Cholistan desert in relation to their life form and tolerance limits. The results showed variable responses of these species in spatial distribution against the salinity gradient. The plants differed considerably in their tolerance level due to development of differential adaptive strategies under extreme salinities. Excretory species like Aeluropus lagopoides and Sporobolus ioclados dominated the sites with highest salinities along with the leafy succulent Suaeda fruticosa. Stem succulents dominated moderate salinities along with spreading stoloniferous Ochthochloa compressa and tussock grass Cymbopogon jwarancusa. Non-succulent Cressa cretica and tussock grass Lasiurus scindicus were mainly distributed to sites with lower and moderate salinities, while non-succulent plants dominated the lowest salinity site. Of the soil physico-chemical characteristics in the Cholistan desert habitats, salinity may have a direct effect on the life form and survival strategies of occurring plants. Thus, the difference in spatial distribution of individual species along salinity gradients suggested that salinity alone is not a responsible factor to determine community structure, but plant tolerance limits and their life habits are also important.