Phenology & Climate Change – Changing Nature’s Clocks

Each spring, people in Northwest Lower Michigan witness the emergence of wildflowers on the forest floor. Then, the buds of hardwood trees burst open, unfurling broad chartreuse leaves. These and other annual events in nature are timed to match the seasons, responding to the changing light, temperature and precipitation.

So, what can such familiar natural events tell us about climate? If the climate is changing, can we see it in the responses of plants and animals?

In this video, the botanist and ecologist, Liana May (Borealis Consulting) explains how an understanding of phenology can help us track climate change. She also describes how a changing climate is impacting familiar plant communities and encouraging some invasive plants.

Working with the Leelanau Conservancy, Liana conducts regular plant surveys on preserves, characterizing the occurrence and abundance of key species. According to Matt Heiman, Land Programs Director for the Leelanau Conservancy, these plant surveys or floristic assessments provide extremely valuable information for the management of land preserves. The surveys also provide a baseline from which to measure change – including the impacts of climate change.

As Matt describes, climate change and variability pose other challenges for natural resource managers by generating possible miss-matches between the phenophases of plants and pollinating insects. For example, sudden early spring warm ups can cause plant buds to burst open before the pollinators are ready or mature enough.

Phenological events such as the leafing out of particular species of shrubs and trees or the flowering of plants are influenced by a number of environmental factors such as light and temperature. But different species of plants respond in different ways.

As Liana notes, some plants are more sensitive to one environmental factor or another. Other plants respond to a combination of environmental factors, making it difficult to predict how climate change will impact native plants.

That’s why many scientists and volunteer conservationists are keeping track of the phenophases of plants and sharing the information with a national database. The evaluation of the data will help resource managers assess the impacts of climate change over time as well as the sensitivity of various ecosystems.

To learn more about phenology and climate change, we recommend visiting the USA National Phenology Network (NPN). NPN encourages citizens and scientists to contribute information to a growing national database on plant phenology and changes observed over time.

To learn more about Liana May and the work she’s doing for the Leelanau Conservancy, check out their blog here.