E. Levesque et al., PHENOLOGICAL AND GROWTH-RESPONSES OF PAPAVER-RADICATUM ALONG ALTITUDINAL GRADIENTS IN THE CANADIAN HIGH ARCTIC, Global change biology, 3, 1997, pp. 125-145
Phenology and growth of Papaver radicatum Rottb. was monitored over fo
ur summers (1990-1993) at 12 sites, along a dolomitic and a granitic a
ltitudinal gradient (330 m a.s.l.-770 m a.s.l.) at Sverdrup Pass, cent
ral Ellesmere Island, Canada. The gradients provided substantial diffe
rences in environmental characteristics. Three of the four seasons (19
90, 1991 and 1993) had more than 400 thawing degree-days (TDD) in the
valley, while the 1992 season had less than 300. The granitic sites ha
d consistently higher temperatures than the dolomitic sites, despite t
heir northerly aspect. Increasing elevation reduced total degree-day a
ccumulation (c. 40 degree-days/100 m) and length of potential growing
season. The proportion of the population producing flower buds was sim
ilar at all sites in any given year, but there were differences among
years. Production of flowers and fruits per site, decreased with altit
ude along the dolomitic gradient in 1991 and 1992. There was no differ
ence in the number of buds or flowers produced per plant with increasi
ng altitude, although larger plants with multiple flowers were found o
nly on low elevation granitic sites. Plants from the dolomitic sites w
ere smaller and flowered, on average, after the site accumulated 150 d
egree-days, while plants on the granitic sites were larger and bloomed
after 200 degree-days. Papaver is able to grow and reproduce over a w
ide range of environmental conditions and moderate climate warming wou
ld likely promote its growth and establishment, unless other factors,
especially snow-free periods and water availability, become limiting.