Brown County Native Woodlands Project
Brown County State Park Invasive Plant Species Mapping
Controlling invasive plants is beneficial to wildlife, wild flowers and woodlands. Once you know what invasive plant species are, they are hard to ignore. Unfortunately it can be hard to get rid of them as well. This statement is true if you own a few acres around your house or if you own 40 – 100 acres of woods. So imagine being charged with caring for 16,000 acres or forest that is used by thousands of people a year, and has over 110 miles of horse trails, hiking and mountain bike trails.
Invasive species have been introduced into Brown County State Park by a variety of methods. Some invasive plants like Autumn Olive, Bush Honeysuckle and Multiflora rose were actually planted in the park to provide food and habitat for wildlife. Other species may have been introduced by pioneers, periwinkle in particular tends to mark the location of pioneer homesteads when found in the woods. Other invasive plants have been introduced over the years in landscaping around the park or possibly by some kind visitor bringing a species to the park because they like it. Japanese knotweed, Dame’s Rocket and Kudzu may all have been introduced unintentionally be the park or friendly visitors. There are other invasive plants that make their way onto a property attached to the fur or hooves of animals, on boots, bikes, horses or mechanical equipment. Some also fly in on the wind or wash in on water in the streams.
No matter how an invasive plant finds the State Park, once it is established they can be difficult to control. The first step in control is knowing what species of invasive plants you have on your property, knowing where they are and how much you have. Once you have this information you can begin an effective and efficient control strategy. For the State Park, knowing where to start on 16,000 acres and what species to target first is a daunting task. To help with this problem, the Brown County Native Woodlands Project applied for a mini-grant in the amount of $1000 from the Brown County Soil and Water and $500 from the Southern Indiana Cooperative Weed Management Area (SICWMA). These funds allowed the Brown County Native Woodlands Project to hire a young forester for 10 weeks. The forester used a GPS unit, data recorder and mapping program provided by The Nature Conservancy. The grant required the forester to walk 19 miles of hiking trails, 20+ miles of mountain bike trails and over 72 miles of horse trails. While walking, the forester mapped the location of every species of invasive plant he encountered, whether it was an individual plant or an area covered by a clump of invasive plants.
During the process of mapping the trails, 14 different species of invasive plants were mapped. There were 2,018 individual occurrences of non-native invasive plants mapped and 285 poly lines where non-native invasive plant occurred in a 3 – 10 foot wide band at least 30 feet long along a trail and 16 non-native invasive plant polygons that were each greater than 0.10 acres. From a species standpoint, Multiflora Rose and Japanese Stiltgrass were the most common species encountered and we were surprised to find a population of Kudzu and Japanese knotweed.
The map created from this project shows the distribution of invasive plants across the state park. This map will be delivered to the state park along with smaller working maps that detail the occurrence of non-native invasive plants in different sections of the park. These smaller maps will be used to actually direct the treatment of invasive plants on the property and hopefully justify funding for invasive plant control for several years to come.
Dan Shaver
The Nature Conservancy - Brown County Hills Project
BCNWP Vice Chair