Phenology

For short-lived spring wildflowers such as wood anemone (Anemone quinquefolia) and Dutchman’s breeches (Dicentra cucullaria), timing is everything. These fleeting plants, known as ephemerals, grow in temperate forests around the world, leafing out and flowering early in spring before the trees towering above them leaf out. Emerge too early, and it will still be winter; emerge too late, and it will be too shady under the forest canopy for essential photosynthesis to happen. Over their evolutionary history, these plants have figured out the best timing for their survival. But climate change is altering spring growing conditions, and plant life is changing along with it. There are many examples of plants shifting flowering time in response to warming temperatures, such as cherry blossoms opening earlier and earlier each year. However, when one part of an ecosystem shifts, will all the organisms that depend on it successfully shift too? Or will they be out of luck? And what...

Henry David Thoreau, the environmental philosopher and author of “Walden”, was a keen observer of seasonal change. In 1862, for example, he wrote in the Atlantic Monthly: “October is the month of painted leaves. Their rich glow now flashes round the world. As fruits and leaves and the day itself acquire a bright tint just before they fall, so the year near its setting. October is its sunset sky; November the later twilight.” Over the past 20 years, researchers have used Thoreau’s observations of plant flowering, leaf emergence on trees and shrubs, bird migration and spring ice melt on Walden Pond to study how these events have changed since the 1850s, largely in response to climate change. Ecologists have also pulled data for modern-day research from museum specimens, journals of hunting guides and bird and butterfly club reports. Comparisons with historical records have provided insights into shifts in the natural world caused by climate chang...

The extreme weather that has battered much of the U.S. in 2022 doesn’t just affect humans. Heat waves, wildfires, droughts and storms also threaten many wild species – including some that already face other stresses. I’ve been researching bee health for over 10 years, with a focus on honey bees. In 2021, I began hearing for the first time from beekeepers about how extreme drought and rainfall were affecting bee colony health. Drought conditions in the western U.S. in 2021 dried up bee forage – the floral nectar and pollen that bees need to produce honey and stay healthy. And extreme rain in the Northeast limited the hours that bees could fly for forage. In both cases, managed colonies – hives that humans keep for honey production or commercial pollination – were starving. Beekeepers had to feed their bees more supplements of sugar water and pollen than they usually would to keep their colonies alive. Some beekeepers who had been in busines...