Volume No. 11, 2002
A new project is under way in Canada aimed at developing potential distribution maps of thousands of native and horticultural plant species (http://g4.glfc.cfs.nrcan.gc.ca/ph_main.pl). The approach is to develop a climatic profile for individual species using new continent-wide climate models. These climatic profiles will be mapped, giving an indication of the possible range of species in relation to meso-scaled climate. We are inviting participation from plant professionals, Master Gardeners, and the public in both Canada and the United States. This note provides some general background information and history behind the project and finishes with an invitation to participate.
At this stage, prospects for undertaking a full-fledged Gap Analysis-type program in Canada similar to that under way in the United States seem limited. Canada is a large country with over 400 million hectares of forest land out of a total land area of over 900 million hectares (see http://www.nrcan-rncan.gc.ca/cfs-scf/national/what-quoi/sof/sof02/overview_e.html for additional statistics). It also has fewer biologists and fewer roads than the United States. Though Canada has no formal “Gap” program, there continues to be growing interest in species modeling generally (see Lipset-Moore et al. 2003 for a summary of a recent workshop on the subject of multi-scale species modeling needs and opportunities in Ontario). Most species modeling occurs under the aegis of forest or environmental management planning initiatives or species-at-risk planning and is therefore targeted at particular species.
A new project led by the Canadian Forest Service (CFS) in Sault Ste. Marie called “Going Beyond the Zones” is aimed at developing potential distribution maps for a large number of native and nonnative tree, shrub, perennial flower, and grass species. Ouellet and Sherk (1967) developed a plant hardiness zone map for Canada based on 7 different climatic variables and field trials at 108 locations across the country for 174 plant species. (The U.S. Hardiness Zone map is based on average extreme minimum temperature.) While work on plant hardiness has continued in several locations across Canada over the years, no new national mapping has occurred until recently (McKenney et al. 2001). That work applied the original plant hardiness model/formula but used more recent climatic data and more modern climate interpolation methods. Changes and obvious limitations in the old and updated zones has kindled interest in developing potential range maps based on more modern species modeling methods.
It is generally well accepted that climate imposes a constraint on plant distributions (Woodward 1987). A bioclimate envelope approach to species mapping has been developed by Henry Nix and colleagues at the Australian National University and has resulted in a set of tools now called ANUCLIM (http://cres.anu.edu.au/outputs/anuclim.html). Nix first applied this approach to the problem of mapping distributions of elapid snakes in Australia (Nix 1986; see also Busby 1991). The approach involves obtaining accurate location data for the plant or animal of interest. These data are used to generate a “bioclimatic profile” of the species using high-resolution climate models. The profile itself is mapped using grids of each of the variables in the profile. Only places that match the profile are mapped. Elith and Burgman (2002) compare ANUCLIM to several other species modeling/mapping approaches. They make the point that species model assessments should be based on the desired application. Our maps can be interpreted as estimates of the climatic domain of the species―a potential range as driven by meso-scale climate, based on estimates of climate where the species is known to occur. Presence-only data are required.
Lindenmayer et al. (1996) provide a good review of the ANUCLIM approach and an application to several commercially important eucalypt species in Australia. Scott et al. (2002) provide a more recent and richer source of literature associated with species modeling generally. The ANUCLIM approach has been successfully used for many ecological studies in Australia and a few other countries and is now being applied to various native and nonnative forest insects and diseases, birds, reptiles, and amphibians in Canada. The approach is described in a Canadian context in McKenney et al. (1998) with some results for reptiles and amphibians on-line at http://www.glfc.cfs.nrcan.gc.ca/landscape/herp_e.html.
Significant effort has now been put into developing seamless climatic and topographic databases to run the ANUCLIM model throughout North America. For example, the USGS Digital Elevation Model (DEM) has been combined with a new Canadian DEM built by the CFS in partnership with the Canada Centre for Topographic Information. Most importantly, seamless climate models have been developed using thin plate smoothing splines as implemented by ANUSPLIN (http://www.glfc.cfs.nrcan.gc.ca/landscape/climate_models_e.html; Hutchinson 1995). ANUCLIM requires spatially continuous climate surfaces to generate bioclimatic profiles.
An important motivation behind the development of this capacity is increased concern over exotic, invasive species and prospects of rapid climate change. However, another appealing application is the development of potential distribution maps for native species and species of more general horticultural interest―our plant list includes both.
The greatest challenge for this project will be to obtain accurate and reliable location data. We are attempting to make use of the power of the Internet, public data, and expert knowledge and data. Our Plant Hardiness Web site enables location and survival data to be entered by experts and the public. Users identify the latitude and longitude of their location. If not provided, elevation, which is essential to achieve accurate climate estimates at each location, will be estimated using a DEM. Users identify which plants are surviving (at least three years) at that location from a comprehensive, but not exhaustive, plant list (currently ~ 6,500 species). Experience in the early stages of this project will influence decisions about adding other plants to the list. We are also asking users to enter some additional basic data about soil conditions and exposure, but this is not essential.
Experts and researchers who have larger quantities of data can contact us directly if they would like to contribute and would prefer to simply e-mail spreadsheet or flat files. Contributions can be confidential and their use restricted to this specific application. Any maps showing location data will only be coarsely georeferenced to no less than 5-10 km resolution to ensure confidentiality. We would also be most willing to provide climate estimates/profiles to scientific contributors, if desired (see http://www.glfc.cfs.nrcan.gc.ca/landscape/climate_models_e.html for a listing of sample variables). Such climate estimates can be useful for other scientific research.
Once sufficient data are entered, climatic profiles for individual species will be generated using several temperature- and precipitation-based variables. Range maps will be posted on our Internet mapping system. Thirty to fifty well-distributed observations are sometimes all that is required to generate reasonable, stable results. An important point, however, is that the maps can be updated relatively easily. Our hope is that both experts and the public will be enticed to contribute, especially if they see their particular area is not well represented.
Over time we will also develop at least two sets of climatic range maps. One set will be based on data from experts and the other based on the data from both experts and the public. We feel it is important to keep these data sources separate, because mistakes in plant identification are possible. We will strive to ensure data quality from all sources. If there appear to be discrepancies, these data will not be used. We will also generate models based on temperature variables only and temperature and precipitation variables combined.
We hope the project is of interest to both Canadians and Americans. Plant data from the United States will greatly aid in developing more robust climatic profiles of individual plant species. To encourage participation from the United States, the potential range maps will include the United States. Already some data from the United States have been contributed, and plans are under way to extend some of the Tree Atlas work of Louis Iverson (USFS) and colleagues (http://www.fs.fed.us/ne/delaware/atlas/index.html) into Canada. More information on this project can be found on the “Going Beyond the Zones” Web site (http://g4.glfc.cfs.nrcan.gc.ca/ph_main.pl).
This project is funded by Natural Resources Canada, Canadian Forest Service but includes the cooperation and assistance of several other organizations and individuals. Thanks to Mike Jennings and an anonymous reviewer for comments on an earlier version of this article.
Busby, J.R. 1991. BIOCLIM―A bioclimate analysis and prediction system. Pages 64-68 in C.R. Margules and M.P. Austin, editors. Nature conservation: Cost-effective biological surveys and data analysis. CSIRO, Australia.
Elith, J., and M. Burgman. 2002. Predictions and their validation: Rare plants in the Central Highlands, Victoria, Australia. Pages 303-313 in J.M. Scott, P.J. Heglund, M.L. Morrison, et al., editors. Predicting species occurrences: Issues of accuracy and scale. Island Press, Washington, DC. 868 pp.
Hutchinson, M.F. 1995. Interpolating mean rainfall using thin plate smoothing splines. International Journal of GIS 9:385-403.
Lindenmayer, D.B., B.G. Mackey, and H.A. Nix. 1996. The bioclimatic domains of four species of commercially important eucalypts from south-eastern Australia. Australian Forestry 59(2):74-89.
Lipsett-Moore, G., D.W. McKenney, and S. Jones. In press. Multi-scale species modelling in Ontario: A workshop on needs and opportunities. The Forestry Chronicle.
McKenney, D.W., B.G. Mackey, J.P. Bogart, J.E. McKee, M.J. Oldham, and A. Chek. 1998. Bioclimatic and spatial analysis of Ontario reptiles and amphibians. Ecoscience 5(1):18-30.
McKenney, D.W., M.F. Hutchinson, J.L. Kesteven, and L.A. Venier. 2001. Canada’s plant hardiness zones revisited using modern climate interpolation techniques. Canadian Journal of Plant Science 81:129-143.
Nix, H.A. 1986. A biogeographic analysis of Australian elapid snakes. Pages 4-15 in R. Longmore, editor. Atlas of elapid snakes of Australia. Australian Flora Fauna Series 7. Australian Government Publications service, Canberra, Australia.
Ouellet, C.E., and L.C. Sherk. 1967. Woody ornamental plant zonation I: Indices of winter hardiness. Canadian Journal of Plant Science 47:231-238.
Scott, J.M., P.J. Heglund, M.L. Morrison, J.B. Haufler, M.G. Raphael, W.A. Wall, and F.B. Samson, editors. 2002. Predicting species occurrences: Issues of accuracy and scale. Island Press, Washington, DC. 868 pp.
Woodward, F.I. 1987. Climate and plant distribution. Cambridge University Press, Cambridge, UK.
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