Invasive Plants

What makes an exotic species invasive?
There are several characteristics that increase the likelihood of an exotic species becoming invasive:

• seed dispersal by animals
• production of many, small seeds
• a long flowering and fruiting season
• a reproductive life that begins within a few years of reaching adulthood
• a lack of specific seed germination requirements, such as a cold period.

Why are invasive species bad?
All plants contribute some good things to their environment, such as reducing carbon dioxide or providing food for animals, but invasive species can threaten the biodiversity of an environment.

Invasive species can spread extensively and quickly, replacing native plants and thereby altering an ecosystem. Once the conditions of an area are changed, new species including pathogens may be able to survive where they previously could not.

Why is biodiversity so important?
A wide variety of animal and plant species is beneficial for several reasons:

Ecologically, all living things are supported by other living things. When one species is removed, other species are likely to suffer. The more complex an ecosystem, the more likely it is to survive for a long period of time, and the less vulnerable it is to damage.

Economically, the more variety there is in the natural world, the more likely we are to meet specific human needs. Everything we buy and sell originates from the natural world.

Culturally, different groups of people around the world feel a connection to nature for various reasons, such as its historical importance or beauty. The diversity of cultures is intricately linked to the diversity of the natural world.

In the Albany Pine Bush…

Invasive species have begun to replace native species in some areas of the Pine Bush. A traditional pine barrens habitat is dominated by species that thrive in dry, acidic, nutrient-poor soil and full sun conditions.

Invasive species first became established in certain disturbed areas such as farmland, golf courses, and lawns. Over time the invasive species contribute nutrients to the soil and decrease the amount of sunlight able to reach the ground, causing native species to lose their competitive advantage.

How are invasive plants controlled in the Pine Bush?
Mechanical treatments such as mowing, cutting, and girdling are used to limit the success of invasive species. Chemical herbicides are also used very sparingly, by applying them directly to the unwanted plant.

Prescribed fire is used to maintain high quality pine barrens and discourage the encroachment of invasive species. Historically, fires occurred in the Pine Bush every 2 to 15 years. The Albany Pine Bush Preserve Commission’s prescribed burn program aims to ensure safe conditions for nearby residents while maintaining native pine barrens habitat.

What can you do to limit the impact of invasive species?
Designing a garden that incorporates native species is one important way to limit the spread of invasives. Many conventional garden plants are not native to the local environment and are frequently able to invade surrounding wild habitat (although not all exotic plant species are invasive). As development increases, natural areas become fragmented. Patches of native plants grown in our yards can serve as corridors giving native species a better chance of survival.

Invasive plants of the Pine Bush

Black locust:

• A deciduous tree
• Deeply furrowed bark
• Attractive white flowers
• Native on the east coast from Pennsylvania southward
• Because of its useful hard wood, it has been planted well beyond its native range
• Able to reproduce quickly by both seeds and root sprouts, creates large clusters that push out native species
  

Aspen:

• Unique invasive species because it is native to the Pine Bush
• A clonal plant (trees close to each other are connected underground through the root system and are genetically identical)
• Very fast growing
• Out-competing desirable pine barrens vegetation in some sites of the Pine Bush
• Fire historically maintained the population, but without periodic burning, their growth can go unchecked
• Commonly controlled in the Pine Bush by girdling the tree (involves stripping a piece of bark all the way around the trunk)
  

Bush honeysuckles:

• A deciduous shrub
• Produces many flowers in the spring, followed by “showy” fruits
• Introduced to the United States from Asia between 1700 and 1900
• Can reduce the diversity of the ground layer and transform areas from prairie to scrubland
• Very hard to eradicate because seeds left in the soil can regenerate, even after a fire

Multiflora rose:

• Large shrub
• Capable of forming nearly impenetrable thickets
• Introduced as an ornamental shrub
• Birds are the primary means of seed dispersal
• Has overtaken thousands of acres throughout the country
• During the 1930’s conservation organizations promoted its spread because it is a source of food and cover for wildlife

Garlic mustard:

• Can form colonies
• Dominates the ground layer, pushing out other species

Purple loosestrife:

• A perennial plant
• Long stalks of purple flowers
• Colonizes wetland habitats
• Large populations can limit food and habitat available for native wildlife
• Difficult to control once it becomes widespread
• Attempting to dig up the roots can actually increase its spread.
• Several years of cutting the plant to the ground is one effective method of control.

Common reed:

• Nearly impossible to pull up without the aid of a backhoe or steam shovel
• Has an extensive rhizome system, which is similar to very thick horizontal roots
• Competes with native plants found in wetland habitats

The Pine Bush Preserve has an extensive system of trails open to the public where you can observe invasive species in competition with native species on a first-hand basis. There are also many volunteer opportunities to help control invasive plants in the Pine Bush. For more information on volunteering at the Pine Bush please contact the Albany Pine Bush Preserve Commission.

If you live in the Glacial Lake Albany Sandbelt and would like to help control invasive species in the Pine Bush by landscaping your home with native plants, please contact the Pine Bush Preserve Commission for more information.