Sunday, December 13, 2015

The Forest Less Diverse

I love to explore new parks. One can find parks at the city, county, state and national level. Each one is a chance to explore the unique plants and communities found in those preserved spaces. There I often find other people enjoying the spaces: walkers, runners, dog owners, and families exploring with their kids.

Sometimes it is all I can do to keep from stopping every visitor and saying “This is not the way the land is supposed to look. This place is overrun with invasive plants from foreign lands and doesn’t reflect the beauty of Georgia.”  I’m sure that most of them would look at me strangely and sidle around me as quickly as possible. Most people are content to have clear paths and green plants in their outdoor experiences.

All that's green here is non-native
A visit to a park near Athens had me with my hand over my mouth recently. The paths through the park were at times carved out of thickets of invasive shrubs: privet (Ligustrum sinense), elaeagnus (Elaeagnus), and bush honeysuckle (Lonicera maackii).

Canopy trees like oaks (Quercus) and sycamore (Platanus occidentalis) soared high into the sky, immune to the invasion below.

One might wonder why green is not good enough. What is the difference between one shrub and another? The issue centers around plant diversity and the role that plants play in the greater community. An area that is choked out with one or two species of plants is not more diverse even though those plants came from another continent. The area becomes less diverse due to excessive competition.

Bush honeysuckle (Lonicera)
In this particular park, the canopy trees that existed prior to invasion are unaffected. Their progeny, however, may find it difficult to germinate when they land on ground that doesn’t get sufficient light or moisture below the thicket of privet. Herbaceous plants – flowering spring and summer plants plus ferns – have lost ground too. The faster-growing invasive plants have gotten the jump on them.

Insects that relied on those native plants have found less and less pollen, nectar and foliage to sustain them. Many insects are specialists, so a downturn in native plant populations equals a corresponding downturn in their populations as well. Birds that eat insects will not thrive here either.

Over time, the shift in the plant population tilts more in favor of the newcomers. Canopy trees may fall with age or due to storms, with few youngsters available to take their place due to reduced germination of their seeds. In order to restore diversity, often humans have to step in.

I was heartened at the end of the day to find signs about invasive eradication efforts getting started. These signs were there to educate the public about what they were doing, how they were doing it, and why it was important. They've got a long way to go, but volunteers will be there to help, especially when they start to see the benefits: plants often return on their own when given a helping hand.

If you've got a chance to help out at a local park with invasive removal, please do so. The benefits to the local ecosystem are immense, and you get a chance to make Georgia more "Georgia" again!


  1. The problem is not having enough people to do the removal.

  2. In Warner Robins, there is a walking trail that happens to be paved next to a series of sewer outlet in the center of an older neighborhood. I call it weed alley. Beautiful trees and plants that often are invasive species. The bright orange nandina berries are present until new blooms. Nothing eats them. Lirope, Popcorn trees, mimosa, English ivy, the list is numerous.
    If my life slows down more, I would like to get Girl Scout and Boy Scout troops to help remove privet in natural areas.

  3. Thanks for this post. It stirred me to go after the Japanese honeysuckle vines that are much easier to spot, now that much of the other vegetation has died back.

  4. We are removing groves of privet that reach 10+ feet tall on property we recently purchased. Our plan is to remove as much Japanese honeysuckle and privet this winter. It is so thick in places that it would be prime habitat for snakes so we'd better get busy before they emerge in spring. I am looking forward to reintroducing natives after we get the invaders eradicated.