The distribution of Nodding Ladies’-tresses (Spiranthes cernua) in Ontario appears to have expanded northward since 1980, based on 15 records within regions of northern Ontario where the flora has been well documented. Nodding Ladies’-tresses is considered a quick response species because it produces thousands of very light, wind-dispersed seeds from a single blossom by asexual reproduction (adventitious embryony). Individual plants are capable of high seed production in situations lacking pollinators and can therefore rapidly produce large populations in new areas.

An increase of 1 degree Celsius in mean yearly temperature over the past three decades is widespread in northern Ontario within the regions of the range extensions. This study concludes that the increase in temperature is sufficient to explain the northerly expansion of the range of Nodding Ladies’-tresses.

The study also projects that, because large areas appear to have already become available to species occurring on the southern edge of the boreal shield ecozone, by 2040 the northern limits of quick response species in this region may have expanded 300 km north of their 1980 limit.

Canadian Field-Naturalist, Volume 125 (2011), Number 1, pp 34-40.