2001 NATURAL HISTORY SOCIETY EXECUTIVE COMMITTEE: 
     
    
   
   
    
     The Natural History Society of Prince Edward Island’s 2000 Executive Committee was re-elected 
     
     at the Annual Meeting held on February 6, 2001. The members present at the meeting expressed their 
     
     appreciation for the work the Executive has done on their behalf. Congratulations go out to Ben Hoteling 
     
     (president), Jim Jenkins (V ice-President) Lois Doan (Secretary), Michelle Johnston (Treasurer), Meike 
     
    
   
   
    
     Keunecke (Director for programs), Eric Marcum (Director, assistant for programs), and Ray Cooke (Past- 
     
     President). 
     
    
   
   
    
     INVASIVE PLANTS: by Kate MacQuarrie 
     
    
   
   
    
     “A mine that modified the landscape on a similar scale [as invasive plants] would be 
     
     subjected to intense scrutiny by the environmental impact assessment process and would 
     
     probably not be approved ”. 
     
    

    
     - W.M. Lonsdale writing in the Australian Journal of Ecology, 1994. 
     
    
   
   
    
     Invasion by non-native plants is now believed to be second only to land development as the 
     
     greatest threat to biodiversity on both a local and global scale. Although high-profile problematic 
     
     introductions such as the European green crab or brown spruce longhorn beetle have focussed attention on 
     
     non-native animals recently (eg. Issue #156 of Island Naturalist), the general public remains largely 
     
     unaware of the biological and economic impacts of non-native plants. 
     
    

    
     Of course, not all non-native plants are problems. About 900 species of non-native plants have 
     
     become established outside of cultivation in Canada, but only 6% of these are considered invasive 
     
     (spreading into natural habitats). Unfortunately, these few dozen invasive species can incur huge 
     
     biological and economic costs. In Canada, nearly 60% of our National Parks - including remote, 
     
     wilderness areas - report non-native vegetation as causing significant ecological impacts. Nearly 20% of 
     
     plants on the national endangered species list are threatened by non-native species. The United States 
     
     alone spends as much as $5.4 billion annually to control non-native plants, and has seen native plant 
     
     communities displaced in more than 437,000 km2 of grasslands and wetlands (that’s an area about 77 
     
     times the size of PEI, or nearly as large as the Yukon Territory). While displacement of native plant 
     
     communities and spread of disease are some highly-visible impacts of non-native plants, less obvious 
     
     impacts include alteration of fire regimes, and ecosystem-level changes such as alteration of productivity 
     
     and energy flow. Despite the huge amount of money spent on control, more than 500 million non-native 
     
     plant individuals are imported to North America each year. 
     
    

    
     Although it was once thought that natural, complex habitats such as mature forests were more 
     
     resistant to invasion, it is now known that even highly diverse and relatively undisturbed ecosystems can 
     
     be threatened by non-native species. PEI's habitats have a long history of human use, and so it is not 
     
     surprising that 33% of all our plants are non-native and some of these species are invasive. Most people 
     
     are aware of the notorious purple loosestrife (Lythrum salicaria), but the 
     
     Island has other invasive species as well. For example, ground ivy 
     
     (Glechoma hederacea) and creeping buttercup (Ranunculus repens) have 
     
     escaped domestication and are now common in habitats such as along 
     
     streams and in wet woodlands where they can become the dominat 
     
     vegetation. Hawkweeds (Hieracium spp) and common Speedwell (Veronica 
     
     ofiicinalis) have invaded even relatively undisturbed forests, where they 
     
     extend well into the interior. For easily found, graphic examples of 
     
    
   
   
    
       
     
    
   
   
    
     HIERACIUM AURANTIACUM 3