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Seasonal differences in growth and leaf physiology between lianas and trees. A test of the dry season growth advantage hypothesis.

Leonor Alvarez Cansino1, Eric Mazane2, Geertje van Der Heijden3, Stefan Schnitzer3
1 Department of Plant Ecology, University of Bayreuth
2 Smithsonian Tropical Research Institute
3 Smithsonian Tropical Research Institute, University of Wisconsin-Milwaukee

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Determining the factors that control large-scale patterns of species distributions is a key goal in ecology, yet the mechanisms responsible for the number of lianas and trees through the tropics with annual rainfall have received little attention. Lianas are key components of most tropical forest and they peak in abundance in seasonally dry tropical forests. The dry season growth advantage hypothesis propose that lianas are more abundant in seasonally dry forest because they may avoid physiological stress by remaining active and growing during dry periods. We tested the dry season growth advantage hypothesis for liana and trees along a steep rainfall gradient across the Isthmus of Panama. We measured liana and tree growth, seasonal physiological responses and leaf traits (N and C content, δ15N, δ13C, LMA, gas exchange, and water potential) in co-occurring lianas and trees in a dry, moist, and wet forest. Lianas had stronger stomatal control and higher water use efficiency than trees in the drier forest, but not the wet forest. Greater leaf-level seasonal resource use strategies and growth during the dry season supports the dry season growth advantage hypothesis and may explain why lianas peak in abundance in seasonally dry tropical forests.



last modified 2014-09-09