In order to do so, ITEX put
together simple protocols that allow scientists to perform similar
experiments in different Arctic sites. The advantage of performing
similar experiments is that the results can later be compared
The Bylot Island Ecological Studies and Environmental Monitoring
project has been considered as an official ITEX study site since
1999. Four plant species have been monitored since then: female
and male Arctic Willow (Salix arctica), Purple Saxifrage
(Saxifraga oppositifolia), Northern Wood Rush (Luzula
confusa) and Mountain Avens (Dryas integrifolia).
Individual plants from these species were marked and their phenological
phases (life stage such as flowering, for example) are monitored
many times each summer. The number of flowers produced per each
plant is also recorded.
Data from the ITEX site gives us information on how plant production,
for example the date at which a plant flowers, changes from year
to year. Analysis of our weather data can later help us determine
which climate factor is the most responsible for these changes
in plant production. In a broader perspective, understanding Arctic
plant responses to various environmental factors may give an insight
on how these plants are likely to react to climate warming.
First Flowering Date
Five years of data is still a relatively small time span to evaluate
the relation between phenological events and climatic factors.
Nevertheless, some tendencies have been observed with our data.
Within each species, the date at which first flowering events
were observed showed small intra-annual variability, but large
inter-annual variability. This means that during one year, most
of the plants of one species tended to produce their first flower
around the same date. However, this first flowering date greatly
varied from year to year.
For all the studied plant species, the date of first flowering
was not influenced by the environmental conditions of the previous
growing season (TDD and number of days above 0°C). However,
first flowering seems to be influenced by the current season climatic
conditions prior to flowering. Indeed, for all plant species except
female S. arctica, flowering is related to June thawing
degree-days. Therefore, for most of the monitored plant species,
flowering is advanced in years with warm temperature in June.
Due to missing values during the first years of sampling, it
is not possible to evaluate the relation between climate and the
number of flowers. In the future, the accumulation of a larger
database will allow us to better assess this relation.