Abstract: Leaf traits reflect the life history of plants. To determine leaf trait variability and plant adaptive strategies to heterogeneous habitats of karst, we measured leaf traits \[leaf area (LA), leaf thickness (LT), specific leaf area (SLA), leaf dry matter content (LDMC), and leaf tissue density (LTD)\] of 18 plant species in the karst region of Pingguo City, Guangxi, China. The results showed there were considerable variations in the five leaf traits. The intraspecific and interspecific variation coefficients were the highest for LA (32.92% and 228.44%, respectively) and lowest for LDMC (9.41% and 20.33%, respectively). Species-level variation in leaf traits was the highest (85.3%-91.3%), followed by plant family groups (28.4%-73.4%). Life form and growth form were the third (12.4%-59.1%) and fourth (3%-24.3%) most important factors in explaining leaf trait variations. The interaction between life form and growth form explained more variation than by single life form or single growth form (26.7%-61.2%). In general, the relationships between leaf traits were significant (P<0.05), except that between LT and LA(P>0.05)or SLA (P>0.05). These findings support those of previous studies and conform to leaf economic spectrum (LES) for karst plants. Evergreen karst species were located at the slow investmentreturn end of the LES, with high LTD and LDMC values but low SLA and LA values. In contrast, deciduous karst species were located at the quick investment-return end of the LES. The results demonstrated that all the examined species could adapt to different habitats with trade-offs among leaf traits. These findings suggested that suitable plant species should be selected and combined with different succession stages, site conditions, and management objectives to accelerate vegetation restoration in karst areas.

Key words: leaf trait, variation, leaf economic spectrum, adaptive strategy, karst.