By Bob Engel, Professor Emeritus of Biology and Environmental Science, Marlboro College 

The super continent Pangaea broke up about 250 million years ago, and the current continents have been drifting ever since. Countering this breakup is the increasingly evident, almost thermodynamic tendency for life to homogenize across those same continents.  

Moneywort (Lysimachia nummularia), an exotic from Europe, found in moist, shady places.

We call these things exotic species--they have come from elsewhere. But when you think about it, almost everything was exotic once. Native Americans? They got here maybe 14,000 years ago. Vermont trees? The first to arrive after the last glacial period was the red spruce--it was just the fastest of the trees racing north (200 km/century) as the climate permitted. If you look further, you find out that a full 27% of the vascular plants in Vermont are not "native." They came from Europe (mostly) with humans. Very few of the plants you see in a field are "native."

A problem arises when some exotic species explosively colonize their new homes. Perhaps unchecked by predators and competitors, these new species literally take over some habitats. Japanese knotweed (a plant I actually like) comes to mind. In some, especially riverine, habitats, it is literally wall-to-wall. No other plants can compete for space and light. Getting rid of it is a Herculean task. Several years of consistent chemical and mechanical (pulling it up) work is necessary for its eradication. A mere 7% of its former rootstock will allow it to come back. This plant will continue to expand here; we have lost the battle, even without any real engagement.

When exotics become invasive, they can change the systems in which they have become developed. Perhaps the biggest concern is that they will completely eliminate the native species they displace. E.O. Wilson, the patriarch of conservation biologists, has placed invasive species in his top five threats to the world's biodiversity. Most Vermont foresters would agree.

Nature loves to surprise us. Sometimes invasives have odd, unpredictable effects. In New England, for example, invasive honeysuckle and buckthorn are preferred by some of our nesting forest birds. The wrinkle is that nest predators take more eggs and baby birds in these nests than they do in nests placed in native forest shrubs. Who could have guessed?

I have a friend who worked in the invasive capital of the world: Hawaii. He was trying to restore the dry forests there. He gave up. In spite of fires, bulldozers, and legions of volunteers, the Africa fountain grass beat them. He told me he dreamed of napalm.

Phenology is not only a fun word to say, it is also a great way to get engaged with the outdoors and contribute as a citizen scientist. The term phenology comes from the Greek word phaino, meaning to show or appear. Phenology is the study of recurring plant and animal life cycle stages--leaves appearing in spring, insects hatching, bird migration, flowers blooming. Phenology also correlates these cycles with weather and climate.

Phenology can let farmers and gardeners know when to plant to avoid frosts and at what phases of plant and insect development to apply fertilizers and pesticides. Phenology can improve our own health by telling us when certain allergens or infectious diseases may be present in our area. Phenology also helps scientists understand such hazardous conditions as fire or drought.

In Vermont, it is critical to maple sugar producers to understand the phenology of the area so they know when to tap their trees. The flowering of plants and the migrations of birds are very sensitive to changes in our climate. Phenological changes to these events can help inform us of changes in our climate and how these changes may affect us.

One of the best things about phenology is that you don't need to be a trained scientist to be part of it! The organizations below offer opportunities for citizens to practice phenology in their own backyards. Explore the links and start keeping your own records. You will be in good company, since many famous historical figures, including Henry David Thoreau and Thomas Jefferson, recorded phenological observations that are still being used to understand how environmental conditions have changed over the last century.

Phenology opportunities:

The Fairbanks Museum's Community of Observers 

Track weather, birds, butterflies, and wildflowers and share your data with the Fairbanks Museum.   

USA National Phenology Network 

Start tracking plants and animals, or share data you have collected already.  

Journey North: A Global Study of Wildlife Migration and Seasonal Change

     for K-12 students.

The Aldo Leopold Foundation's phenology resources 

Learn about data collected by Aldo Leopold and Henry David Thoreau, and download a guide for collecting your own data at home.  

North American Bird Phenology Program 

Volunteer to transcribe bird migration records for a U.S. Geological Survey database.