Ecological adaptation strategies of plant functional groups in the upper reaches of the Tarim River based on leaf functional traits

Plant functional traits can reflect plants' long-term adaptive responses to the environment. However, the ecological adaptation strategies adopted by desert plants in plant functional groups to cope with extreme environments remain unclear. Therefore, in this study, plants belonging to 16 common desert species were collected to measure leaf chemical and physiological traits in the extremely arid region along the northern edge of the Tarim Basin. Cluster analysis was used to divide the plants into different functional groups to reveal the response and adaptation mechanisms of plants to environmental and resource changes at a higher level. The results showed that (1) based on plant leaf functional traits, the 16 desert plants could be divided into three plant functional groups, showing significant differences in chemical element contents and ratios, osmoregulatory substance content, and water use efficiency (p<0.05). (2) Functional group 1 (FG1) had the highest leaf nutrient and water use efficiency and soluble sugar content, lower N and P content and the lowest soluble protein content, indicating a passive strategy of high consumption. Plants in functional group 2 (FG2) were poor in leaf N, rich in P and had the lowest organic carbon content, soluble sugar content, and water use efficiency, indicating a relatively conservative strategy. Members of functional group 3 (FG3) were rich in leaf C, N and P, and their proline, soluble protein and sugar content were all high, indicating a rapid resource acquisition and growth strategy. (3) There were significant correlations among most leaf traits of each functional group (p<0.05); although the relationships were inconsistent, extremely significant correlations existed between the organic carbon and nonstructural carbon contents in FG1, C/P and soluble sugar contents in FG2, and total N and proline contents in FG3 (p<0.01). These results indicate that desert plant functional groups adopt different ecological strategies and contribute to a comprehensive understanding of how plants adapt and respond to extremely arid environments, providing a scientific basis for the protection of desert vegetation.