XVI International Botanical Congess

Phenology is an effective means of monitoring the biological impacts of climate change. Since spring flowering of perennials occurs in response to accumulated temperature, global warming should be reflected by long term trends toward earlier spring development. Phenological data from Canada and Europe show trends toward earlier flowering for many species. Sixty years of data on first flowering of Populus tremuloides near Edmonton, AB show a 6.5 day shift (0.26 days/year) in the last 25 years. When the bloom times of five Alberta species are compared with satellite information and pacific ocean temperatures there is a correlation between earliness of bloom and El Nino events. The Internet program Plantwatch (www.devonian.ualberta.ca/pwatch/) involves observers reporting bloom times for lilac and seven native species.