Shifting seasons: How climate change is affecting plants and ecosystems
Shifting seasons:
How climate change is affecting plants and ecosystems
By: Sabrina Careri
Shifting seasons
How climate change is affecting plants and ecosystems
Canada is experiencing shifting weather patterns and accelerating biodiversity loss, and even small signs like early blooms in gardens, reflect deeper environmental change. Plants are responding to changes in temperatures and ecosystems, reshaping the natural rhythms that sustain our landscapes and communities.
During my usual morning walk today, I noticed something unusual: the rhododendron outside my apartment was starting to bloom. It’s not even March yet. The timing struck me as ironic because, at the same moment, I was on FaceTime with my mom in Ontario, where temperatures continue to drop to minus 20°C, during one of the coldest and wettest winters Toronto has seen in decades.
Meanwhile, here in Vancouver, our typically temperate climate has been unusually dry this winter. In fact, we’ve been on track for the first snow-free winter in 43 years, with far less rain during the usual October-to-March downpour. These extreme contrasts in weather patterns across Canada offer insights into how climate change is reshaping our daily lives and our local ecosystems.
Global perspective on flowering patterns
Recently, I came across a study in The Guardian about tropical plants flowering earlier or later than they historically have due to climate change. The article covers a new study that examined 8,000 plants dating back 200 years and found shifts in flowering times that could cause a serious ripple effect through entire ecosystems.
Researchers highlighted that when flowering patterns shift, it affects ecosystem norms such as fruit-eating timelines and the seed-dispersing animals, pollinators, and other plants. Even a few days’ difference can create cascading impacts that negatively impact ecosystems. While this study focused on tropical plants, the implications are global and resonate with what is happening right here in Canada.
Plants and climate change in Canada
Canada may not be tropical, but our native and ornamental plants are just as sensitive to changing climate patterns. Last year, Natural Resources Canada updated the Plant Hardiness Zones map, which guides gardeners on what plants can grow where. The first update since 2014, the new map shows that approximately 80% of Canadian land has warmed by between half and a full zone. The hardiness zones are determined by factors such as minimum temperatures during the coldest months and maximum temperatures during the hottest months, as well as frost, rainfall, and snowfall patterns too.
Simply put, the map tells us which plants can survive and thrive where. While this means that plants that once struggled in certain areas may now thrive because of warming temperatures, the changes have the potential to disrupt ecosystems by potentially favoring some species and threatening others.
What does it mean for biodiversity?
Shifts in flowering times and plant hardiness zones reflect deeper ecological conditions. Plants may bloom before or after pollinators are active, disrupting food chains and impacting the composition of our ecosystems and the ranges of wildlife species which may travel north or decline altogether, leading to ripple effects across entire ecosystems.
The rhododendron outside my apartment may be an early bloomer this year, but climate data and projections show that this shift reflects deeper changes in our natural rhythms where plants are responding to declining biodiversity and a climate in flux.
Understanding these changes allows us to make informed choices at home in our gardens and across our communities. That includes planting species suited to the updated hardiness zones and prioritizing native plants that support local biodiversity. It also means holding governments accountable to their climate commitments, including Canada’s 2030 climate target, the international Paris Agreement and 30×30 biodiversity pledge. Climate change might feel abstract when we see it in headlines or on social media, but its impacts are unfolding right outside our front doors in our gardens and in the plants that sustain our communities.
