Ecological facilitation between two epiphytes through drought mitigation in a subtropical rainforest
Pei-Yu Jian1, Feng Sheng Hu, Chiao Ping Wang
1Department of Life Science, National Taiwan Normal University, Taipei, Taiwan.
Plos One
|June 7, 2013
Summary
Asplenium antiquum facilitates Haplopteris zosterifolia survival by providing water during droughts. This epiphyte interaction is crucial for maintaining rainforest biodiversity, especially with climate change.
Area of Science:
- Ecology
- Plant Interactions
- Tropical Botany
Background:
- Positive species interactions, or facilitation, are vital for ecological community structure, particularly under environmental stress.
- Epiphytes in rainforests often form multi-species clumps, indicating potential interspecies facilitation, but mechanisms remain unclear.
- Understanding epiphyte co-occurrence patterns is essential for predicting community dynamics in changing environments.
Purpose of the Study:
- To investigate the co-occurrence patterns and interspecific interactions between two rainforest epiphytes: Asplenium antiquum and Haplopteris zosterifolia.
- To elucidate the mechanisms driving these interactions, focusing on resource competition and facilitation, particularly water availability.
- To assess the role of substrate-forming epiphytes in mitigating drought stress and supporting epiphyte diversity.
Main Methods:
- Field surveys to quantify co-occurrence and size-class associations of A. antiquum and H. zosterifolia.
- Reciprocal removal experiments to assess the impact of each species on the other's growth.
- Greenhouse drought experiments, nutrient, and stable isotope (δ13C, δ15N) analyses to determine resource exchange and water relations.
Main Results:
- H. zosterifolia showed higher co-occurrence with A. antiquum (45%) than vice versa (17%).
- Removal of A. antiquum substrate significantly reduced H. zosterifolia growth, indicating a facilitative effect.
- A. antiquum enhanced water availability to H. zosterifolia through substrate water storage and shading, evidenced by higher foliar δ13C in co-occurring plants during drought.
Conclusions:
- Asplenium antiquum provides significant drought mitigation for Haplopteris zosterifolia, primarily through its water-retentive substrate.
- Substrate-forming epiphytes play a critical role in maintaining epiphyte diversity in regions prone to water limitations.
- These facilitation mechanisms are increasingly important for epiphyte survival under anthropogenic climate change and increasing drought frequency.
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