Phenology of Vascular Plant Flowering in Edmonton and Across Alberta

Abstract

Phenology, the study of the timing of life cycle events, has a long history in Europe where networks of observers provide data on growth of native and crop plants to agro-meteorological departments. It has much potential for Alberta. For this thesis, two phenological studies were carried out over the growing seasons of 1987 and 1988. Both concentrated on the phenophases (growth stages) of native perennial plant species. The intensive study described the flowering phenology of 127 vascular plant species along a 1.5 km transect in Edmonton’s Whitemud ravine (aspen parkland). In general, flowering times were earlier in 1987 and 1988 than average, corresponding with higher than average temperatures. Temperatures fluctuated more in the bottom of the ravine, and flowering was generally earlier at the ravine top. Phenodynamic strips illustrate species’ development over time and plant wheels show the growing season divided into subseasons marked by the start of indicator species’ phenophases. The extensive study involved volunteers across Alberta to record three flowering phenophases - 10%, 50%, and 90% flowering - for up to 15 species of native "wildflowers". Flowering dates were received from 60 observers in 1987 (1300 dates), and 190 observers in 1988 (approximately 3000 dates). Linear contour mapping using SPANS on a microcomputer illustrated flowering progressions for each species in colour. Trends in flowering were generally from SE Alberta to the NW, continuing on to the foothills, mountains and the north, with a heat island effect causing earlier flowering at cities. Plant species and phenophases were evaluated with respect to their value for phenology. The data from this ongoing survey have large potential benefits for agriculture, forestry, climatology, medicine, tourism and environmental education.