PLANT SEEDLING PERFORMANCE TRAITS IMPACT ON SUCCESSFUL RECRUITMENT IN VARIOUS MICROHABITATS FOR FIVE ALPINE SAUSSUREA SPECIES

Abstract

Habitat heterogeneity and species-specific traits (seed mass) both impact on seedling performance and recruitment. Five species of Saussurea DC., from the Qinghai-Tibetan Plateau were selected to study seedling performance and recruitment under various microhabitats.. Results showed that seedling emergence and survival were significantly affected by light regimes, seed mass and their interactions. The RGR and R/S were affected by light and nutrient levels and seed mass during all growth stages. There was a significant interaction between nutrient and light on seedling survival. Light was directly related to seedling survival but nutrient availability was only indirectly related to seedling recruitment, by influencing the RGR and R/S ratio. Seedling survival was positively related to RGR and to R/S in the 100-day growth period. Our results suggested that seedlings improved their survival by altering their RGR and R/S under various microhabitats and the light and nutrient microhabitats affect seedling recruitment by impacting on seedling emergence and growth performance.