Murdoch University Research Repository

Welcome to the Murdoch University Research Repository

The Murdoch University Research Repository is an open access digital collection of research
created by Murdoch University staff, researchers and postgraduate students.

Learn more

Latitudinal gradient of floristic condition among Great Lakes coastal wetlands

Johnston, C.A., Zedler, J.B. and Tulbure, M.G. (2010) Latitudinal gradient of floristic condition among Great Lakes coastal wetlands. Journal of Great Lakes Research, 36 (4). pp. 772-779.

Link to Published Version:
*Subscription may be required


Coastal wetland vegetation along the Great Lakes differs strongly with latitude, but most studies of Great Lakes wetland condition have attempted to exclude the effect of latitude to discern anthropogenic effects on condition. We developed an alternative approach that takes advantage of the strong relationship between latitude and coastal wetland floristic condition. Latitude was significantly correlated with 13 of 37 environmental variables tested, including growing degree days, agriculture, atmospheric deposition, nonpoint-source pollution, and soil texture, which suggests that latitude is a good proxy for several environmental drivers of vegetation. Using data from 64 wetlands along the U.S. coast of Lakes Huron, Michigan, Erie, and Ontario, we developed linear regressions between latitude and two measures of floristic condition, the Floristic Quality Index (FQI, adj. r2=0.437, p<0.001) and the first axis scores from a non-metric multidimensional scaling of wetland plant cover (MDS1, adj. r2=0.501, p<0.001). Departures from the central tendency of these regression models represented wetlands of better or worse condition than expected for their latitude. This approach provides a means to identify wetlands worthy of preservation, to establish vegetation targets for wetland restoration, and to forecast changes in floristic quality associated with future climate change.

Item Type: Journal Article
Publisher: International Association for Great Lakes Research
Copyright: © 2010 International Association for Great Lakes Research
Item Control Page Item Control Page