University of Pennsylvania
Department of Earth and Environmental Science
240 South 33rd Street
Philadelphia, PA 19104-6316
Fax: (215) 898-0964
1. Composition, Structure, Dynamics, Productivity and Climate of Eocene Forests of the Canadian High Arctic: Comparing Reconstructions from Field Measurements and Nearest Living Relatives (see http://www.sas.upenn.edu/earth/arctic/).
2. I am concerned with better understanding the origin, ecology, and evolution-biodiversification of the boreal and temperate forests. To do this I employ a multi-disciplinary approach integrating ideas and information from a number of areas. My expe rtise covers a broad range of disciplines including plant taxonomy and systematics, DNA sequencing, ecology, paleobotany, resin chemistry (chemotaxonomy), biogeography, plant-fungal interactions, geology, and geomorphology. This broad-based approach not o nly enables me to ask and study very specific aspects about terrestrial ecosystems, but also, to consider the relationships that exist between the biotic and abiotic components of specific ecosystems and interpret the results at the local, regional, and g lobal scale.
I have been studying the spatial and temporal distribution patterns of the Pinaceae and Taxodiaceae, both important constituents of the boreal and temperate forests, so that I may be able to better understand the mechanisms involved in the developmen t of modern vegetational assemblages. In particular, I have recently focused on Asia (Himalayan region) because it have been largely unaffected by glacial forces relative to North America and Europe, and therefore provides an excellent model to study and better understand the evolution and ecology of temperate and boreal floras and forest dynamics in four dimensions (latitude, longitude, altitude, and time) with climate as a major parameter. By understanding the modern distribution patterns of forest con s tituents and their ecology and physiology it is then possible to determine the intrinsic and extrinsic factors that govern the distribution of individual species. These factors may include soil characteristics, parent rock, climate, rainfall, topography , temperature, the physiological requirements of the plant, fungal-symbionts (mycorrhizae), and plant-animal co-evolutionary processes.
Assessment of a particular species distributional range and role within the environment however, requires that the species be very well defined. This often requires extensive field-based collection of fertile and vegetative organs from individuals wi thin a population for detailed taxonomic analysis so that the natural range of anatomical and morphological variability can be determined. Once the number of species represented in a population and their natural range has been determined it is then possi b le to assess the environmental and ecological factors governing a particular species distribution pattern and their role within specific ecosystems.
Tools used in my taxonomic study of anatomical and morphological features include the more traditional techniques such as light microscopy, thin section, SEM, TEM, and morphometric and statistical analyses, but also, modern systematic techniques such as DNA sequence divergence data using polymerase chain reaction (PCR) and resin analysis using pyrolysis-gas chromatography-mass spectroscopy.
My use of fossil plants and pollen to reconstruct past environments and determine ancient species distribution patterns is intimately linked with studies of modern vegetational assemblages and their environments. By studying plant fossils I am better able to examine the rate and types of anatomical and morphological changes through time, speciation rates, and relationship between species distribution patterns and climatic and environmental change through time.
My work on plant-fungal interactions provides an important new dimension to understanding how forest ecosystems function and evolve. Ninety-five percent of all plants require some type of mycorrhizal symbiont to survive and successfully compete in th eir environments. If we are to understand the development of vegetation within various
ecosystems, we must then begin to address the processes occurring in the rhizosphere and interpret them in the context of forest ecology and biodiversification. Understanding of the relationship between these plants and their fungal symbionts are pro viding significant insight into forest-growth patterns, nutrient cycling, and successional patterns presently and in the past.
My DNA research has proven to be extremely valuable in understanding the intergeneric and intraspecific relationships among plant taxa. I have recently completed a study on the evolutionary relationships among members of the genus Tsuga (Pinaceae) us ing molecular divergence data from the ITS region, part of the 18-26S nuclear ribosomal gene family. I am currently sequencing the trnL/trnF region, part of the chloroplast genome to improve the phylogenetic resolution of a few regions that the ITS regio n could not resolve. Use of DNA sequencing is a powerful tool for systematic research and continued research in this area will inevitably lead to many new and exciting discoveries. I also plan to use molecular sequencing to help determine the amount of ge n etic variation or biodiversity among and within populations of plants. Understanding of the genetic variability within plant populations will provide important data on rates of genetic and phenotypic change and may shed light on speciation processes.
Refereed Publications (last 5 years):
1998. Stockey, R.A., LePage, B.A, and Pigg, K.B. Permineralized fruits of Diplopanax (Cornaceae, Mastixioideae) from the middle Eocene Princeton chert of British Columbia. Review of Palaeobotany and Palynology 103:223-234.
1998. Satoru, K., Sweda, T., LePage, B.A., and Basinger, J.F. A new method to estimate accumulation rates of lignites in the Eocene Buchanan Lake Formation, Canadian Arctic. Palaeogeography, Palaeoclimatology, Palaeoecology 141:115-122.
1998. Currah, R.S., Stockey, R.A, and LePage, B.A. An Eocene tar spot on a fossil palm and its fungal hyperparasite. Mycologia 90:667-673.
1998. Aulenback, K.R. and LePage, B.A. Taxodium wallisii gen. et sp. nov.; the first occurrence of Taxodium from the Upper Cretaceous of North America. International Journal of Plant Sciences 159:367-390.
1997. Nobori, Y., Hayashi, K., Kumagai, H., Kojima, S. LePage, B.A., and Sweda, T. Reconstruction of a Tertiary fossil forest from the Canadian High Arctic using three-dimensional computer graphics. Journal of Forest Planning 3:49-54.
1997. LePage, B.A., Currah, R.S., Stockey, R.A., and Rothwell, G.W. Fossil ectomycorrhizae in Eocene Pinus roots. American Journal of Botany 84: 410-412.
1995. Anderson, K.B. and LePage, B.A. Analysis of fossil resins from Axel Heiberg Island, Canadian Arctic. American Chemical Society Symposium Series 617: 170-192.
1995. LePage, B.A. and Basinger, J.F. The evolutionary history of Pseudolarix (Pinaceae). International Journal of Plant Sciences 156: 910-950.
1995. LePage, B.A. and Basinger, J.F. The evolutionary history of the genus Larix (Pinaceae). United States Department of Agriculture, Forest Service, Intermountain Research Station, General Technical Report GTR-INT-319: 19-29.
1994. LePage, B.A., Currah, R.S., and Stockey, R.A. The fossil fungi of the middle Eocene Princeton Chert, British Columbia, Canada. International Journal of Plant Sciences 155: 829-836.
1994. LePage, B.A. and Basinger, J.F. Additional note on the preservation of fossil leaf compressions, impressions, and cuticle. Journal of Paleontology 68: 1164.
1993. LePage, B.A. and Basinger, J.F. A new technique for the preservation of fossil leaf compressions, impressions, and cuticle. Journal of Paleontology 67: 128-134.
1991. LePage, B.A. and Basinger, J.F. A new species of Larix (Pinaceae) from the Early Tertiary of Axel Heiberg Island, Arctic Canada. Review of Palaeobotany and Palynology 70: 89-111.
1991. LePage, B.A. and Basinger, J.F. Early Tertiary Larix from the Buchanan Lake Formation, Canadian Arctic, and a consideration of the phytogeography of the genus. In Tertiary fossil forests of the Geodetic Hills, Axel Heiberg Island, Arctic Archip elago. R L. Christie and N.J. McMillan (eds.). Geological Survey of Canada, Bulletin 403: 67-82.
1989. LePage, B.A. and Basinger, J.F. Early Tertiary Larix from the Canadian High Arctic. Musk-Ox 37: 103-109.
1988. Basinger, J.F., McIver, E.E., and LePage, B.A. The fossil forests of Axel Heiberg Island. Musk-Ox 36: 50-55.
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