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plant monitoring
    Mesic Communities
  Mesic Communities  
The International Tundra Experiment (ITEX) is a network of scientists from more than 11 countries, studying tundra plants in more than two dozen Arctic locations. The main goal of the ITEX network is to understand the response of tundra plant species to climate changes, especially to a warming in summer air temperatures. Salix arctica and/et Saxifraga oppositifolia © Austin Reed

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 among sites.

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 nivalis) 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.

buds of Dryas integrifolia - bourgeons de Dryas integrifolia © Esther Lévesque
flowers of Dryas integrifolia – fleurs de Dryas integrifolia © Esther Lévesque
Dryas integrifolia in seeds – Dryas integrifolia en graines © Esther Lévesque

Data from the ITEX site gives us information on how plant production, for example the number of flowers it produces 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

From 1999 to 2005, the average date of first flowering for the species monitored in mesic communities was the 29 June for Saxifraga oppositifolia, 3 July for Salix arctica male, 2 July for Salix arctica female, 4 July for Luzula nivalis and 11 July for Dryas integrifolia. For all these species, except for male S. arctica, the date of first flowering has been advancing since 1999. Over a 7-year period, the first flowering date has been advancing of 4 days for D. integrifolia, 6 days for S. oppositifolia, 12 days for S. arctica female and 14 days for L. nivalis.


Number of Flowers Produced

For most of our species, the average number of flowers produced annually showed large annual differences.

On average, each D. integrifolia plant produced 8.9 flowers per year. For the other plant species, the average annual flower production was lower with 2.3 flowers per plant for S. oppositifolia, 1 for L. nivalis, 0.5 for male S. arctica and 0.2 for female S. arctica. However, since 2000-2001, the number of flowers produced by plants of D. integrifolia, S. oppositifolia and L. nivalis has been declining.