Climate and Modern Neotropical Plant Distributions: Macroecological and Paleoecological ImplicationsEPA Grant Number: FP916377
Title: Climate and Modern Neotropical Plant Distributions: Macroecological and Paleoecological Implications
Investigators: Punyasena, Surangi W.
Institution: University of Chicago
EPA Project Officer: Graham, Karen
Project Period: January 1, 2004 through December 31, 2006
Project Amount: $111,344
RFA: STAR Graduate Fellowships (2004) RFA Text | Recipients Lists
Research Category: Fellowship - Terrestrial Ecology and Ecosystems , Academic Fellowships , Ecological Indicators/Assessment/Restoration
The climatic correlates of extant plant family and genus distributions have macroecological and macroevolutionary significance. Environmental preferences shared by individuals of a given family or genera reveal inherited ecophysiological characteristics. These characteristics provide the basis for interpreting compositional changes in fossil pollen and fossil plant records. They also provide the basis for predicting ecosystem response to ongoing climate change. The objective of this research project is to investigate the role that spatial differences in local climate play in governing the occurrence and abundance of plant families and genera in one model system in modern South American tropical forests.
I used published data from vegetation surveys of 121 forest transects and seasonal climate data that include temperature, precipitation, and insolation variables. The data include 161 families and 1,038 genera. The results identify: (1) tropical families and genera that demonstrate the greatest sensitivity to variations in climate; and (2) the climate parameters that most affect modern plant distributions.
The relationship between climate and higher-order taxonomic distributions is explained by a small number of variables. First-order variation in abundances among families in this data set is governed, surprisingly, by temperature, accounting for nearly 40 percent of the variation observed. Second-order variation is governed by precipitation particularly the number of wet days during the growing season. This accounted for more than 18 percent of the variation observed. Among genera, however, the nature of the relationship between climate and abundance is family specific.
The results run counter to patterns in species richness, number of individuals, and vegetation type, all of which correlate most strongly with water availability. In contrast, the results suggest that although richness may be most strongly affected by precipitation, the taxonomic composition of tropical forests is governed by temperature. Abundance patterns of taxa most sensitive to climatic variation, including large families such as Fabaceae and Bignoneaceae, also can be used in paleoclimatic interpretation of floras with no modern analogue.