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Habitat‐related error in estimating temperatures from leaf margins in a humid tropical forest
Author(s) -
Burnham Robyn J.,
Pitman Nigel C. A.,
Johnson Kirk R.,
Wilf Peter
Publication year - 2001
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.2307/2657093
Subject(s) - liana , habitat , canopy , biology , ecology , tropical forest , tropics , physical geography , geography
Leaf margin characters are strong predictors of mean annual temperature (MAT) in modern plant communities and widely used tools for reconstructing paleoclimates from fossil floras. However, the frequency of nonentire‐margined species may vary dramatically between different habitats of the same forest. In this paper we explore the potential for this habitat variation to introduce error into temperature reconstructions, based on field data from a modern lowland forest in Amazonian Ecuador. The data show that the provenance of leaves can influence temperature estimates to an important degree and in a consistent direction. Woody plants growing along lakes and rivers underestimated MAT by 2.5°–5°C, while those in closed‐canopy forest provided very accurate predictions. The high proportion of liana species with toothed leaves in lakeside and riverside samples appears to be responsible for a large part of the bias. Samples from closed‐canopy forest that included both lianas and trees, however, were more accurate than tree‐only or liana‐only samples. We conclude that paleotemperature reconstructions based on leaf margin characters will be misleading to the extent that fossilization provides a better record of certain habitats than others. The preponderance of lake and river deposits in the angiosperm fossil record suggests that underestimation of mean annual paleotemperature may be common.