Clonal Plant Ecology, Forest Canopy Biology, Restoration Ecology & Global Change

What’s the species interaction in epiphyte community in forest canopies along latitudinal and altitudinal gradients, particularly in Southeast Asia? It was conceived that competition was the basic ecological process, whereas stress–gradient hypothesis (SGH) implied that the role of competition decreased and facilitation increased with the degrees of stresses. The species interaction thus should be a line or spectrum with one end of negative (competition) and the other positive (facilitation). Because the conditions become more fluctuating, heterogeneous and stressful from the forest floor to forest canopy, the interaction of epiphytes may tend to be the end of facilitation while that of terrestrial plants, the other end of competition. However, we know little about how the epiphytes interact with each other and what their effects on community assembly are, although there are plenty of related studies on terrestrial plants. Furthermore, with the increase of latitude and altitude, the environment and resource conditions may be more and more stressful. For instance, temperature and moisture (rainfall) get higher from Indo-China Peninsular to Peninsular Malaysia and from north to south in Southeast Asia, while the weather changes from seasonality to aseasonality. We thus predict the species interaction of epiphytes may move from negative in south to positive in north in Southeast Asia.

On the other hand, the diversity of functional traits with complementary functions in a community drives biodiversity–ecosystem functioning relationships. What’re the mechanisms underlying the functioning of epiphyte biodiversity in forest carbon, hydrology and nutrient fluxes? We need to know the patterns of functional traits of epiphytes along the environmental variation. First of all, we need to develop a list of expected differences between epiphytes and other plant groups and to place epiphytes in the ‘global spectrum of plant form and function’. However, we have few data of functional traits of epiphytes and know little about the global pattern of functional traits of epiphytes.

Education:  

Aug. 2017 – Sep. 2018, Visiting Scholar, University of California, Los Angeles (UCLA) 

Sep. 2012 – Jul. 2017, Ph.D. Ecology, University of Chinese Academy of Sciences 

Sep. 2006 – Jul. 2009, M.Sc. Ecology, University of Chinese Academy of Sciences

Sep. 2012 – now, Restoration Ecology Group, Xishuangbanna Tropical Botanical Garden (XTBG), Chinese Academy of Sciences

Aug. 2017 – Sep. 2018, Visiting Scholar, University of California, Los Angeles (UCLA)

Jul. 2009 – Aug. 2012, Secretary of CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences

(*Corresponding author; # joint first authors)

1)       Lu H-Z, Brooker R, Song L, Liu W-Y*, Sack L, Zhang J-L, Yu F-H*. 2020. When facilitation meets clonal integration in forest canopies. New Phytologist. 225: 135–142. https://doi.org/10.1111/nph.16228

2)       Sun J-Q, Chen Q, Li H-Y, Chang Y-F, Gong H-D, Song L, Lu H-Z*. 2019. Progress on the clonality of epiphytic ferns. Biodiversity Science. 27: 1184–1195. (in Chinese with English abstract) https://doi.org/10.17520/biods.2019120

3)       Zhang L-M#, Lu H-Z#, Alpert P, Song L, Liu W-Y, Yu F-H*. 2019. Higher benefits of clonal integration in rhizome-derived than in frond-derived ramets of the tropical fern Bolbitis heteroclita. Flora. 257: 151415. https://doi.org/10.1016/j.flora.2019.06.001

4)       Chen Q, Sun J-Q, Song L, Liu W-Y*, Yu F-H, Li S, Gong H-D, Lu H-Z*. 2019. Trait acclimation of the clonal fern Selliguea griffithiana to forest epiphytic and terrestrial habitats. Ecological Research. 34: 406-414. https://doi.org/10.1111/1440-1703.12002

5)       Chen Q#, Lu H-Z#, Liu W-Y*, Wu Y, Song L, Li S. 2019. Obligate to facultative shift of two epiphytic Lepisorus species during subtropical forest degradation: insights from functional traits. Forest Ecology & Management. 435: 66-76. https://doi.org/10.1016/j.foreco.2018.12.037

6)       Lu H-Z#, Song L#, Liu W-Y*, Xu X-L, Hu Y-H, Shi X-M, Li S, Ma W-Z, Chang Y-F, Fan Z-X, Lu S-G, Wu Y, Yu F-H*. 2016. Survival and growth of epiphytic ferns depend on resource sharing. Frontiers in Plant Science. 7: 416. https://doi.org/10.3389/fpls.2016.00416

7)       Song L#*, Lu H-Z#, Xu X-L, Li S, Shi X-M, Chen X, Wu Y, Huang J-B, Chen Q, Liu S, Wu C-S, Liu W-Y*. 2016. Organic nitrogen uptake is a significant contributor to nitrogen economy of subtropical epiphytic bryophytes. Scientific Reports. 6: 30408. https://doi.org/10.1038/srep30408

8)       Lu H-Z, Liu W-Y*, Yu F-H, Song L, Xu X-L, Wu C-S, Zheng Y-L, Li Y-P, Gong H-D, Chen K, Li S, Chen X, Qi J-H, Lu S-G*. 2015. Higher clonal integration in the facultative epiphytic fern Selliguea griffithiana growing in the forest canopy compared to the forest understorey. Annals of Botany. 116: 113-122. https://doi.org/10.1093/aob/mcv059

9)       Huang J-B, Liu W-Y, Li S, Song L, Lu H-Z, Shi X-M, Chen X, Hu T, Liu S, Liu T. 2019. Ecological stoichiometry of the epiphyte community in a subtropical forest canopy. Ecology and Evolution. 9: 14394–14406. https://doi.org/10.1002/ece3.5875

10)    Li S*, Liu W-Y*, Shi X-M, Liu S, Hu T, Song L, Lu H-Z, Chen X, Wu C-S. 2019. Non-dominant trees significantly enhance species richness of epiphytic lichens in subtropical forests of southwest China. Fungal Ecology. 37: 10-18. https://doi.org/10.1016/j.funeco.2018.10.005

11)    Wu Y, Song L, Liu W-Y*, Liu W-J, Li S, Fu P-L, Shen Y-X, Wu J-E, Wang P-Y, Chen Q, Lu H-Z. 2018. Vascular epiphytes utilize more fog water than their hosts in an Asian tropical karst forest during the dry season. Forests. 9: 260. https://doi.org/10.3390/f9050260

12)    Shi X-M, Song L*, Liu W-Y, Lu H-Z, Qi J-H, Li S, Chen X, Wu J-F, Liu S, Wu C-S. 2017. Epiphytic bryophytes as bioindicator of atmospheric nitrogen deposition in a subtropical montane cloud forest: response patterns, mechanism, and critical load. Environmental Pollution. 229: 932-941. https://doi.org/10.1016/j.envpol.2017.07.077

13)    Li S*, Liu S, Shi X-M, Liu W-Y*, Song L, Lu H-Z, Chen X, Wu C-S. 2017. Forest type and tree characteristics determine the vertical distribution of epiphytic lichen biomass in subtropical forests. Forests. 8, 436. https://doi.org/10.3390/f8110436

14)    Zhou W-J, Lu H-Z, Zhang Y-P*, Sha L-Q, Schaefer D A, Song Q-H, Deng Y, Deng X-B. 2016. Hydrologically transported dissolved organic carbon influences soil respiration in a tropical rainforest. Biogeosciences. 13: 5487-5497. https://doi.org/10.5194/bg-13-5487-2016

15)    Chen X, Liu W-Y*, Song L, Li S, Wu C-S, Lu H-Z. 2016. Adaptation of epiphytic bryophytes in the understorey attributing the correlations and trade-offs between functional traits. Journal of Bryology. 38: 110-117. https://doi.org/10.1080/03736687.2015.1120370

16)    Wu C-S, Liang N-S, Sha L-Q*, Xu X-L, Zhang Y-P*, Lu H-Z, Song L, Song Q-H, Xie Y-N. 2016. Heterotrophic respiration does not acclimate to continuous warming in a subtropical forest. Scientific Reports. 6: 21561. https://doi.org/10.1038/srep21561

17)    Song L*, Yao Y-L, Ma W-Z, Liu W-Y*, Li S, Chen K, Lu H-Z, Cao M, Sun Z-H, Tan Z-H, Nakamura A. 2015. Bole bryophyte diversity and distribution patterns along three altitudinal gradients in Yunnan, China. Journal of Vegetation Science. 26: 576–587. https://doi.org/10.1111/jvs.12263

18)    Song L, Zhang Y-J, Chen X, Li S, Lu H-Z, Wu C-S, Tan Z-H, Liu W-Y*, Shi X-M. 2015. Water relations and gas exchange of fan bryophytes and their adaptations to microhabitats in an Asian subtropical montane cloud forest. Journal of Plant Research. 128: 573-584. https://doi.org/10.1007/s10265-015-0721-z

19)    Li S, Liu W-Y*, Li D-W, Song L, Shi X-M, Lu H-Z. 2015. Species richness and vertical stratification of epiphytic lichens in subtropical primary and secondary forests in southwest China. Fungal Ecology. 17: 30-40. https://doi.org/10.1016/j.funeco.2015.02.005

20)    Wu Y, Song L, Liu Q, Zhao M-X, Lu H-Z, Tan Y-H, Liu W-Y*. 2016. Diversity and floristic characteristics of vascular epiphytes in the tropical forest of Xishuangbanna. Biodiversity Science. 24: 271-279. (In Chinese with English abstract) https://doi.org/10.17520/biods.2015308

21)    Wu Y, Song L*, Chen X, Lu H-Z, Li S, Shi X-M. 2016. Advances in ecological studies of epiphytes using canopy cranes. Chinese Journal of Plant Ecology. 40: 508-522. (In Chinese with English abstract) https://doi.org/10.17521/cjpe.2015.0424

22)    Shi X-M, Qi J-H, Song L, Liu W-Y*, Huang J-B, Li S, Lu H-Z, Chen X. 2015. C, N and P stoichiometry of two dominant seedlings and their responses to nitrogen additions in the montane moist evergreen broad-leaved forest in Ailao Mountains, Yunnan. Chinese Journal of Plant Ecology. 39: 962-970. (In Chinese with English abstract) https://doi.org/10.17521/cjpe.2015.0093

23)    Chen X, Liu W-Y*, Song L, Wu C-S, Li S, Lu H-Z. 2015. Applicability of three photosynthesis models for epiphytic Homaliodendron flabellatum. Journal of Northeast Forestry University. 43: 142-145, 149. (In Chinese with English abstract)

On one hand, how do various epiphytes adapt to and coexist in the canopies in tropical and sub-tropical forests? I’m interested in the clonality of epiphytes and its adaptation in tropical and sub-tropical forests. At first, we found many epiphytes were able to grow clonally in nature, e.g. almost all lichens and bryophytes, many epiphytic ferns, orchids and bromeliads. What deserves to be mentioned is that different from terrestrial ferns, more epiphytic fern species in Southwest China have long-creeping rhizomes, which mean the traditional clonal growth. Second, we found that clonal integration was one of adaptation strategies of epiphytes to heterogeneous habitats in forest canopies, and that there was higher clonal integration in the facultative epiphytic ferns growing in the forest canopy compared with the forest understory. Under the background of anthropic activities and land-use changes, disturbance and microhabitat fragmentation are ubiquitous in forests. It is reasonable to predict that microhabitat fragmentation affects the performance of epiphytes in forest canopy where varies in environmental conditions, structure and resources. Our results showed that the fragment size of clonal epiphytes had significant effects on survival probability and growth of individuals and that there was significant interaction effects between fragmentation and age of epiphytes. Third, according to the development of epiphyte community, vascular epiphytes come after the establishment of the epiphytic mats consisted of bryophytes and lichens. We found that there were intra- and inter- specific facilitations (e.g. clonal integration within species and facilitation between non-vascular and vascular species) among epiphytes in community assembly in forest canopies. It implied that the disappearance of an epiphytic species may have domino effects on the others. Meanwhile, using the isotope labelling methods, we found that various vascular epiphytes preferred different nitrogen forms (i.e. ammonium, nitrate and organic nitrogen) and that the N economics of non-vascular epiphytes (e.g. bryophytes) differentiated from vascular epiphytes (e.g. ferns and seed plants). We, therefore, inferred that facilitation within clonal species and between plant groups and ecological niche differentiation of N resources may shape the assembly of epiphyte communities in forest canopies where resources are limited and heterogeneously distributed in space and time.

On the other hand, epiphytes are sorted along several axes of environmental variation, such as precipitation gradients, elevation or height above the forest floor, and what’s the pattern of functional traits of vascular epiphytes from forest floor to forest canopy? Forest canopies house ca.50% of terrestrial biodiversity. As a key component of tropical and subtropical floras, epiphytes serve important ecological functions in forest hydrology and nutrient fluxes. Because of the contrasting microhabitats between forest canopies and forest understories, we found that for facultative epiphytes, the morphological, anatomical and physiological traits of epiphytic individuals can mitigate water scarcity at some cost of a reduced photosynthetic capacity, whereas terrestrial individuals can afford to improve the light capture to a higher photosynthetic capacity without any water stresses. Since among-individual variation is the substrate for natural selection, these results open interesting ecological and evolutionary questions for the future. Therefore, further studies should focus on how the epiphytic individuals, which have a lower photosynthetic capacity, are maintained in facultative epiphyte populations, whether they are frequent or rare, and whether they have a differential fitness.

2018.8. (New Orleans, USA), 2018 ESA Annual Meeting. 'Effects of Clonality on Heavy Metal Tolerance of Clonal Ferns'. (Poster)

2018.7-8. (Maine, USA), 12th Clonal Plant Workshop. 'Intra- and inter-specific facilitation shapes community assembly in forest canopies'. (Oral 1).

2018.7-8. (Maine, USA), 12th Clonal Plant Workshop. 'Does clonal integration vary with clonal forms of fern under stresses of heavy metals?' (Oral 2).

2016.8. (London, UK), 7th International Canopy Conference: Patterns and processes in canopy science. 'Effects of fragmentation and age on performance of clonal epiphytes'. (Oral).

2016.8. (Hainan, China), 7th Tropical Forest Ecology Conference in China. 'Effects of clonal forms on clonal integration of a clonal fern'. (Oral).

2015.10. (Xishuangbanna, China). International Workshop on Forest Canopies: Frontiers of Ecosystem Services. 'The interaction of coexisting epiphytes in SW China'. (Oral).

2015.8. (Třeboň, Czech Republic). 11th Clonal Plant Workshop. 'Survival depends on resource sharing: evidences from the epiphytes in a montane moist forest, SW China'. (Oral).

2014.12. (Beijing, China). The First Chinese Graduate Forum on Global Change: Global Change Studies - Power of Interdisciplines. ‘The Effects of Climate Change on Epiphytes in the Forest Canopy’ (Oral).

2014.1. (Xishuangbanna, China). The Third Xishuangbanna International Symposium - Botanical Gardens and Climate Change. ‘Vital role of Clonal Integration in Forest Canopy Rather Than Understory - A Case of Ferns’ (Oral).

2013.11. (Xishuangbanna, China). Advanced Field-course in Ecology and Conservation - XTBG, China 2013 (AFEC-X 2013). ‘Epiphytic Fern Ecology’ (Oral); Epiphytic Lichen/Fern Ecology Research Technique Practice (Field practice guider).2013.10. (Shanghai, China). Conference of Chinese Ferns, 2013. ‘Clonal Integration and Its Ecological Adaptation of Epiphytic Ferns’ (Oral).

Lawren Sack,  Department of Ecology and Evolutionary Biology, University of California Los Angeles, USA

Rob Brooker, The James Hutton Institute, Aberdeen, UK

Fei-Hai Yu, Beijing Forestry University & Taizhou University

Xing-Liang Xu, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences

Shu-Gang Lu, Yunnan University

He-De Gong, Southwest Forestry University