Hua-Zheng Lu1, Wen-Yao Liu2, Fei-Hai Yu3, Liang Song3, Xing-Liang Xu3, Chuan-Sheng Wu1, Yu-Long Zheng3, Yang-Ping Li1, He-De Gong3, Ke Chen1, Su Li3, Xi Chen1, Jin-Hua Qi3, Shu-Gang Lu2. 1. Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla 666303, China, School of Nature Conservation, Beijing Forestry University, Beijing 100083, China, Key Laboratory of Ecosystem Network Observation and Modeling, Chinese Academy of Sciences, Institute of Geographic Sciences and Natural Resources Research, Beijing 100101, China, Faculty of Ecotourism, Southwest Forestry University, Kunming 650224, China, Institute of Ecology and Geobotany, Yunnan University, Kunming 650091, China and University of Chinese Academy of Sciences, Beijing 100049, China Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla 666303, China, School of Nature Conservation, Beijing Forestry University, Beijing 100083, China, Key Laboratory of Ecosystem Network Observation and Modeling, Chinese Academy of Sciences, Institute of Geographic Sciences and Natural Resources Research, Beijing 100101, China, Faculty of Ecotourism, Southwest Forestry University, Kunming 650224, China, Institute of Ecology and Geobotany, Yunnan University, Kunming 650091, China and University of Chinese Academy of Sciences, Beijing 100049, China. 2. Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla 666303, China, School of Nature Conservation, Beijing Forestry University, Beijing 100083, China, Key Laboratory of Ecosystem Network Observation and Modeling, Chinese Academy of Sciences, Institute of Geographic Sciences and Natural Resources Research, Beijing 100101, China, Faculty of Ecotourism, Southwest Forestry University, Kunming 650224, China, Institute of Ecology and Geobotany, Yunnan University, Kunming 650091, China and University of Chinese Academy of Sciences, Beijing 100049, China liuwy@xtbg.ac.cn shuganglu@163.com. 3. Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla 666303, China, School of Nature Conservation, Beijing Forestry University, Beijing 100083, China, Key Laboratory of Ecosystem Network Observation and Modeling, Chinese Academy of Sciences, Institute of Geographic Sciences and Natural Resources Research, Beijing 100101, China, Faculty of Ecotourism, Southwest Forestry University, Kunming 650224, China, Institute of Ecology and Geobotany, Yunnan University, Kunming 650091, China and University of Chinese Academy of Sciences, Beijing 100049, China.
Abstract
BACKGROUND AND AIMS: The advantage of clonal integration (resource sharing between connected ramets of clonal plants) varies and a higher degree of integration is expected in more stressful and/or more heterogeneous habitats. Clonal facultative epiphytes occur in both forest canopies (epiphytic habitats) and forest understories (terrestrial habitats). Because environmental conditions, especially water and nutrients, are more stressful and heterogeneous in the canopy than in the understorey, this study hypothesizes that clonal integration is more important for facultative epiphytes in epiphytic habitats than in terrestrial habitats. METHODS: In a field experiment, an examination was made of the effects of rhizome connection (connected vs. disconnected, i.e. with vs. without clonal integration) on survival and growth of single ramets, both young and old, of the facultative epiphytic rhizomatous fern Selliguea griffithiana (Polypodiaceae) in both epiphytic and terrestrial habitats. In another field experiment, the effects of rhizome connection on performance of ramets were tested in small (10 × 10 cm(2)) and large (20 × 20 cm(2)) plots in both epiphytic and terrestrial habitats. KEY RESULTS: Rhizome disconnection significantly decreased survival and growth of S. griffithiana in both experiments. The effects of rhizome disconnection on survival of single ramets and on ramet number and growth in plots were greater in epiphytic habitats than in terrestrial habitats. CONCLUSIONS: Clonal integration contributes greatly to performance of facultative epiphytic ferns, and the effects were more important in forest canopies than in forest understories. The results therefore support the hypothesis that natural selection favours genotypes with a higher degree of integration in more stressful and heterogeneous environments.
BACKGROUND AND AIMS: The advantage of clonal integration (resource sharing between connected ramets of clonal plants) varies and a higher degree of integration is expected in more stressful and/or more heterogeneous habitats. Clonal facultative epiphytes occur in both forest canopies (epiphytic habitats) and forest understories (terrestrial habitats). Because environmental conditions, especially water and nutrients, are more stressful and heterogeneous in the canopy than in the understorey, this study hypothesizes that clonal integration is more important for facultative epiphytes in epiphytic habitats than in terrestrial habitats. METHODS: In a field experiment, an examination was made of the effects of rhizome connection (connected vs. disconnected, i.e. with vs. without clonal integration) on survival and growth of single ramets, both young and old, of the facultative epiphytic rhizomatous fern Selliguea griffithiana (Polypodiaceae) in both epiphytic and terrestrial habitats. In another field experiment, the effects of rhizome connection on performance of ramets were tested in small (10 × 10 cm(2)) and large (20 × 20 cm(2)) plots in both epiphytic and terrestrial habitats. KEY RESULTS: Rhizome disconnection significantly decreased survival and growth of S. griffithiana in both experiments. The effects of rhizome disconnection on survival of single ramets and on ramet number and growth in plots were greater in epiphytic habitats than in terrestrial habitats. CONCLUSIONS: Clonal integration contributes greatly to performance of facultative epiphytic ferns, and the effects were more important in forest canopies than in forest understories. The results therefore support the hypothesis that natural selection favours genotypes with a higher degree of integration in more stressful and heterogeneous environments.