Abstract
Tropical ferns are characterized by a high diversity of plant life forms, yet there have been few large-scale studies on the functional ecology of these different forms. We examined epiphytic, hemiepiphytic, and terrestrial ferns, and asked whether there are differences in the mineral nutrition and water relations across different growth forms of a diverse assemblage of species. We measured specific leaf area, leaf nitrogen concentrations, and natural abundance of the stable isotopes δ15N and δ13C of 48 fern species from 36 genera across a wide range of habitats at La Selva Biological Station in Costa Rica. We found that epiphytes were significantly different in all measured variables from hemiepiphytic and terrestrial species, and that terrestrial and soil-rooted hemiepiphytes were indistinguishable in all variables excluding SLW. A multivariate analysis revealed that aspects of N nutrition were the most reliable at separating epiphytic species from other life forms. Our study demonstrates that the natural abundance of both C and N as well as N relations and leaf morphology are useful when segregating different plant life forms, and that the N cycle of epiphytic and terrestrial habitats function independently from each other.
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Acknowledgments
This work was supported by an NSF Doctoral Dissertation Improvement Grant to JEW, a grant from the A.W. Mellon Foundation (to CLC), an NSF Postdoctoral Research Fellowship (Grant No. 0309827 to CLC), and the NSF Center for Embedded Networked Sensing at UCLA (PWR). Authors would also like to thank the Organization for Tropical Studies and the staff of La Selva Biological Station for their assistance in facilitating this research.
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Communicated by Mercedes Bustamante.
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Watkins, J.E., Rundel, P.W. & Cardelús, C.L. The influence of life form on carbon and nitrogen relationships in tropical rainforest ferns. Oecologia 153, 225–232 (2007). https://doi.org/10.1007/s00442-007-0723-1
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DOI: https://doi.org/10.1007/s00442-007-0723-1