Dandelions and Climate Change on PEI

One of the first plants to bloom on PEI in the spring is the very common yellow flower of the dandelion. Dandelions are very hardy masters of survival and will pop up in the same area year after year. They can teach us a lesson about climate change. When they are cut frequently they have adapted by producing more seeds than their closely related brethren who live in meadows (Solbrig, 1971). This shows that they can respond or adapt to dramatic differences in their environmental surroundings and are thus worth considering as an indicator of a changing world. A study at Indiana University led by Xianzhong Wang, 2007 revealed that dandelions exposed to a high concentration of CO2 ,which is projected to occur with climate change, grew more, bigger, taller flowers and big parachutes when compared to plants grown at CO2 levels of the present day.

Blooming dandelions indicate that soil temperature has reached between 10° and 12°C which is about the same temperature when soil microbes become active (Trail, 2007).

The first date a dandelion appeared in spring was tracked by James Hunter, meteorological observer, of South Kildare, PEI from 1880 to 1892. The Island Naturalist Newsletter recorded the dates that a first spring dandelion was observed from 2010 to 2021. The observations from these two sources which were recorded over 100 years apart, can provide a phenological indication of a climate change trend which may have occurred between these two eras. The James Hunter observations reveal an average date of first blooming of the dandelion flower of May 26th whereas in the recent observation period ending in 2021, the average date of first blooming for the dandelion is May 1st. This difference of over 3 weeks appears to be an indication that soil temperatures are getting warmer earlier in the spring over time which is one consequence of a gradually warming climate.

First Sighting of Dandelion Flower by James Hunter
First Sighting of Dandelion Flower, Island Naturalist Newsletter


Sources: The population biology of dandelions, Solbrig, 1971; Dandelions and Climate Change: Lessons from Your Front Lawn, Raffaele, 2010; Island Naturalist Newsletter, various issues; Amateur Phenology, Trail, 2007;  Reproduction of Dandelion (Taraxacum Officinale) in a higher CO2 environment, McPeek & Wang, 2009; James Hunter Meteorological Observations, Environment Canada Records.

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