Importance of fire in alvar ecosystems - Evidence from the burnt lands, eastern Ontario

Vascular plants recorded within 50 one metre square quadrats in 1997 in an area cut and burned 37 years earlier revealed an unusually high species div ersity with 87 native vascular plant species, which is roughly twice as hig h as that recorded in various open areas of alvars that have not recently b een burned. Site conditions appear to have favoured native species over wee dy aliens, the latter accounting for 21% of species in quadrats, but having low cover values. The sampled area was dominated by graminoid plants and s hrubs, and was transitional between alvar shrubland and alvar grassland. Th e saplings present were mostly Trembling Aspen, Populus tremuloides, and Wh ite Spruce, Picea glauca. The cut and burned area included 16 rare and/or r estricted species. Some of the prominent vascular plants serve as larval fo odplants for restricted butterflies, and the high species diversity and mor e mesic conditions in successional openings ensure adequate adult nectar so urces. The burned site also provided habitat for rare birds. Considering th ese observations and because the vast majority of alvars have burned within the past few centuries, it is concluded that successional alvar burns dese rve recognition as an important part of the alvar ecosystem and that burnin g of an alvar habitat is an appropriate management consideration. Managemen t plans should account for certain fire-susceptable features such as ancien t trees and arthropod populations.