The Fall 2009 Parsons Lab Lecture: Range and Richness of Vascular Land-Plants: The Role of Variable Light

Abstract:
Since the time of Darwin it has been recognized that the average continuous range of latitudes occupied by the individual plant species found locally increases with increasing latitude, while the number of different species found locally (i.e. the local richness of species) decreases. General agreement has developed that climate is somehow responsible, and this work provides, apparently for the first time, a bioclimatically-based theoretical explanation of these observed structures in extra-tropical vegetation communities.

Range and richness are found theoretically to be inversely related as was noted observationally by Rapoport (1975), and agreement of both theories with observations is found to be excellent at extra-tropical latitudes. [Currently in the publication process, this work will appear shortly as a research monograph in the AGU books program.]