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The Alwyn H. Gentry Forest Transect Data Set

Global Patterns of Plant Diversity NOW AVAILABLE from MBG Press!

Alwyn H. Gentry and Theodore A. Parker III, arguably the leading authorities on the botany and ornithology of tropical America, met an untimely death when their small airplane crashed into an isolated mountain ridge in western Ecuador on August 3, 1993. The pilot and Eduardo Aspiazu, an Ecuadorian ecologist and President of the Guayaquil chapter of Fundacion Natura also died in the crash and three others survived. This event prematurely ended the career of one of the greatest plant explorers and botanists of all time.

At the time of his death, Gentry was involved in a myriad of projects. The Missouri Botanical Garden has remained committed to bringing as many as possible of these projects to conclusion and to ensuring that the results are appropriately published and that his data is made available to researchers. His studies of Bignoniaceae are being completed by William G. D'Arcy (deceased 2000) and Warren D. Hauk. The work will include completion of treatments of Bignoniaceae for a variety of floristic projects and also publication of the "Gentry Invitation Series." Gentry's collections and his database of over 43,000 herbarium collections are available through the Missouri Botanical Garden and online.

In addition to his impressive studies on the systematics of Bignoniaceae and tropical floristics, Gentry was involved since the early 1970's in building a unique data set of tropical and temperate forest samples. In this major undertaking, Gentry was motivated by the fundamental questions of how and why forest diversity and floristic composition vary from one location to another. Many of his publications examine the correlations between diversity and taxonomic composition of forests with a variety of environmental variables, particularly precipitation, elevations, and latitude. Over 22 years, he collected data from 226 sites on six continents. Gentry and his collaborators collected all plants with stem diameters equal to or exceeding 2.5 cm diameter at breast height (dbh) along ten 2 x 50 m transects, totaling a tenth of a hectare at each site.

Al Gentry certainly never imagined that the data that he and his collaborators had amassed from 226 0.1 ha transects were, in fact, ready to be summarized. Yet the value of this incomparable data set is enormous. To ensure that Gentry's ecological data receive maximum use and are readily available to the biological research community, the Missouri Botanical Garden has committed to two related projects:

1) The data from individual transects are being made available to the research and conservation communities through this web site. The information presented here includes the raw data from each of the 226 transect sites along with some introductory material explaining how the data can be accessed, the conditions under which the data can be used, and an explanation of the tabular method in which the data are presented.

2) The data will be summarized in a volume being prepared by Oliver Phillips and James S. Miller for publication in Monographs in Systematic Botany from the Missouri Botanical Garden entitled "Global Patterns of Plant Diversity: Alwyn H. Gentry's Forest Transect Data Set." The volume will summarize the data from each site, including environmental and diversity information and a taxonomic summary of the species that were encountered. The volume will also provide full context for the information including a discussion of the history of Gentry's transect studies, an in depth description of the methodology used to collect the data, a summary of the patterns arising from the overall results, and a summary of the significance of the studies.

Data from Individual Transects

Before accessing data for individual sites or downloading part or all of the transect data, it is requested that individual users read the conditions for use of the data.

Conditions for use of the Gentry Forest Transect Data

The Missouri Botanical Garden is committed to making Al Gentry's transect data available to all researchers but does make several requests to help us track usage and insure that Gentry's work is properly acknowledged.

Researchers who make use of the data in publications are requested to acknowledge Alwyn H. Gentry, the Missouri Botanical Garden, and collectors who assisted Gentry or contributed data for specific sites.

Additional Information

The information that is provided with each transect site is further documented from a number of other sources. Information about voucher specimens may be obtained by searching the TROPICOS database. Specimen information is also available on the Internet by searching for the plant name at http://www.tropicos.org/ and using the specimen lists and maps button. The capacity to conduct Web searches for unidentified specimens by collector and collection number is currently under development and is expected in the near future.

Additional information about each site will be available in "Global Patterns of Plant Diversity: Alwyn H. Gentry's Forest Transect Data Set" currently in preparation by Oliver Phillips and James S. Miller for publication in Monographs in Systematic Botany from the Missouri Botanical Garden. The volume will provide information about environmental variables, precise location, collectors and voucher specimens, and a summary of floristic diversity data for each site.


The collection of data, processing and identification of voucher specimens, and compilation and analysis of the data were enormous tasks which could never have been completed without contributions from research colleagues, assistants, students, and volunteers. Without their support, the data set would never have reached this size or significance. We have tried to compile a list of all of those who contributed, but our efforts will certainly fall short and we apologize for any omissions. A complete list of the hundreds of people who contributed data sets or helped collect data in the field, process herbarium collections, identify the voucher specimens, and computerize and analyze the data will be published in the volume summarizing the data. Special thanks are given to Nancy Hediger who was responsible for organizing the data presented here in their final form.

Numerous organizations provided financial support for Gentry's research. The National Science Foundation awarded several grants that directly or indirectly supported the transect studies (BSR 830-5040; BSR 834-2764; BSR 86-07113; DEB 75-20325; DEB 800-6253; INT 790-6840) and joint support was also received from Colciencias and the National Science Foundation (OIP 75-18202; INT 79-20783). The U.S. Agency for International Development, MacArthur Foundation, and Mellon Foundation provided support for activities in Peru and the World Wildlife Fund provided support for studies in Madagascar. The National Geographic Society provided six grants to Gentry (1400-74; 1982-79; 2303-81; 2602-83; 3149-85; 3783-88) and provided additional support in a grant to W. Duellman (Univ. of Kansas) and Gentry. He received support from the Pew Charitable Trust Fellowship and was a Pew Scholar from 1991 until the time of his death. His work with Conservation International provided the means to survey 15 additional sites.

Financial support to bring many of Gentry's studies to a conclusion was provided by continuing support of the Pew Charitable Trusts and National Geographic Society. Specific awards were also made from the Geraldine R. Dodge Foundation, Lounsberry Foundation, Wallace Genetic Foundation, and Winslow Foundation.



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