Conservation Biology of Eastern Tallgrass Prairie: Integrating Issues of Management and Restoration for the 21st Century
Nyberg, Dennis .
Vegetation Dynamics on a Remnant Prairie: Difficulties Measuring Rates of Colonization and Extinction.
Floral inventories of the 2.1 ha Woodworth Prairie in Glenview Illinois (USA) have been published in 1929, 1969, 1981 and 2001. Additionally, there is a record of species seen in each year since 2000 on this small original prairie. To use the floral lists to calculate rates of extinction and colonization, the lists must be made to conform to a single taxonomic authority. The 428 unique entries were reduced to 271 legitimate names by eliminated spelling errors and other trivial differences and changes in taxonomy. Misidentifications occur. Using range and ‘potential confusion’ information I decided only 238 taxa were ever part of the flora. Each taxa can be placed into one of 15 types of presence (P) absence (A) sequence, e.g., PAAA is a species present in 1929, but not seen thereafter. There was at least one species in each of the 15 types. Between ‘29 & ‘69 there were 19 gains and 25 losses, between ‘69 and ‘81 there were 70 gains and 15 losses, between ‘81 & ‘01 there were 34 gains and 25 losses. There have been more colonizations (123) than extinctions (65) at this small site. Taxa were grouped into exotics (58), native-but-not-prairie (68) and prairie species (112). Thirty of the ‘colonists’ were prairie species. New prairie species have appeared since 2001. Because species can be invisibly present as seeds and be difficult to distinguish when not in flower, comparisons of species lists will tend to exaggerate change. Floral lists will be much more useful if they include all dates and time spent doing the inventory, an explicit description of boundaries, GPS information on routes meandered and the names of individuals doing species determinations.
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Website of the Prairie Study Site
1 - University of Illinois at Chicago, Biological Sciences mc066, 845 W. Taylor St., Chicago, IL, 60607, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Williford B/Hilton
Date: Wednesday, July 11th, 2007
Time: 9:45 AM