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Pennsylvania’s Rare, Threatened, and Endangered Plants

Pennsylvania is home to approximately 3,000 plant species, roughly two-thirds of those are considered native to the commonwealth. Of these native plants, 604 of them are considered rare throughout the state.

Pennsylvania’s rare plants are currently classified as follows:

Classification
Current Number of Species listed under Chapter 45
Extirpated
106
Endangered
228
Threatened
78
Vulnerable
3
Rare
41
Tentatively Undetermined
148
Special Populations
0
TOTAL
604
 

Why Are Native Plants Important?

Different plant species make up a plant community or an ecosystem. The balance of an ecosystem can be impacted by the loss of a species. This can have negative effects on all species, plants, and animals in an ecosystem.

Native plants are important to native wildlife and pollinators, and provide greater ecosystem services (such as flood prevention and soil stabilization) than non-native plants.

Rare native plants can indicate the health of an ecosystem. Plants can be rare because their habitats are uncommon or have become degraded. When a common plant becomes rare, it often indicates that a habitat needs help.

What makes plants rare?

Many factors can threaten populations of plants and cause them to become rare. These include situations that limit gene flow among populations, loss of individuals, or competition for resources.

Some of the most common threats to plants in Pennsylvania include:

  • Habitat loss and fragmentation, due to development or conversion of habitat
  • Invasive plants displacing native plants
  • Creation of more edge habitat, increasing the threat of invasive plant species
  • Selective browsing by white-tailed deer or other wildlife may prevent plants from reproducing
  • Over-collected by humans of showy, edible or medicinal plants

What is DCNR Doing about Rare Plants?

DCNR collects and analyzes data about plants. When the Department has enough information to change a species’ status, it does so through a regulation change. By classifying plants, DCNR communicates the level of protection a plant needs.

DCNR provides recommendations for active management for these species to preserve and enhance their populations. DCNR provides information through the following:

  • Pennsylvania Conservation Explorer -- users have access to plant community information
  • Pennsylvania Natural Diversity Inventory environmental review -- provides review for potential impacts to threatened and endangered plant species; available through the PA Conservation Explorer
  • Education on invasive plants -- provides management information for this threat to native plants
  • Information on using native plants -- provides alternatives to potentially invasive landscaping plants, and benefits native pollinators
  • Updating classifications -- maintains an up-to-date list of plants that need protection in Pennsylvania. More information about classification updates can be found on the right

Rare Plants on DCNR Lands

From open areas to mature forests, DCNR lands host a wide range of plant communities and the department considers the diversity of plants in its management approach. DCNR uses planning to protect manage common and rare plants on DCNR lands.

Important plant communities are protected or designated for plant conservation such as natural and wild areas, wild plant sanctuaries, or high conservation value forests. These sites are managed using appropriate techniques and practices to promote and improve growing conditions for rare plants or may limit certain activities in other areas to conserve sensitive plant resources.

Invasive plant species are a major threat to plant communities as they can out-compete native species, alter habitats, and disrupt life cycles of native invertebrates.

Invasive species management on DCNR lands is important to limit the impact of invasive plants on native plant communities. Also, part of that approach is supplemental plantings with native plants. Here’s what DCNR is doing to benefit native wild plants:

  • Planting and Seeding Guidelines (PDF) -- These guidelines focus on native plantings for DCNR lands, which lessens the threat of invasive species.
  • Invasive Plant Management Plans -- DCNR has developed several tiers of planning to deal with invasive species, at the Department level, bureau, and site specific levels.
  • Pollinator Planting Guidelines (PDF) -- These recommendations help revegetation projects benefit native pollinators.
  • Planning and designation of important plant habitats -- DCNR uses special designations to protect some exemplary populations and communities of rare plants in wild plant sanctuaries, wild areas, natural areas, and high conservation value forests.

Jurisdictional Responsibility

DCNR obtains authority from two acts -- one gives authority to survey ecological features and the other to classify and manage native wild plants.

The Wild Resource Conservation Act (PDF) (WRCA) established a procedure for the conservation, classification, and protection of wild plants and charged the Department of Environmental Resources with that responsibility. This act required the Department of Environmental Resources to conduct investigations on native wild plants regarding populations, distribution, habitat needs, limiting factors and other biological and ecological data to classify the plants and determine management needs.

Later, the Conservation and Natural Resources Act (Act 18) of 1995 split the Department of Environmental Resources into the Department of Environmental Protection and created the new Department of Conservation and Natural Resources.

Act 18 gave the WRCA responsibilities to the DCNR. Pennsylvania code Title 17 Chapter 45, the Conservation of Pennsylvania native Wild Plants, is DCNR’s regulatory effort to carry out the responsibilities of the WRCA. Since the DCNR Bureau of Forestry’s mission includes the conservation of native wild plants, the responsibility of implementing Chapter 45 and the WRCA has been the bureau’s.

The Listing Process

DCNR has a robust process of public participation, data gathering, and input. Anyone in Pennsylvania can petition DCNR to change a plant’s status.

DCNR’s process for making changes to the list of classified plants involves stakeholder groups, particularly the Pennsylvania Biological Survey’s Vascular Plant Technical Committee (VPTC -- the technical committee of the Pennsylvania Biological Survey focusing on plants), and the Rare Plant Forum (RPF -- the public function of the Vascular Plant Technical Committee).

Through public meetings and technical committee meetings, in addition to DCNR’s own investigations, information is obtained on plants to aid in determining classification changes. The VPTC, made up of experts in the botanical field including academics, consultants, natural history museums, and non-profits, meet twice a year to make recommendations on species listings to DCNR.

The RPF includes experts and amateur enthusiasts, and meets once a year to discuss trends and present new research on plants, including species taxonomy, inventories or field surveys, and genetic studies.

Some of the data that is used to determine plant statuses include:

  • Number of known populations
  • Threats
  • Habitat decline
  • Level of information available

Status Definitions

The regulation, Conservation of Native Wild Plants, gives DCNR the status definitions used to classify plants that are in decline in Pennsylvania.

  • Pennsylvania Endangered -- A classification of plant species which are in danger of extinction throughout most or all of their natural range within this commonwealth, if critical habitat is not maintained or if the species is greatly exploited by man. This classification also includes populations of plant species that have been classified as Pennsylvania Extirpated, but which subsequently are found to exist in this commonwealth.
  • Pennsylvania Extirpated -- A classification of plant species believed by the department to be extinct within this commonwealth. The plants may or may not exist outside this commonwealth. If plant species classified as Pennsylvania Extirpated are found to exist, the species automatically will be considered to be classified as Pennsylvania Endangered.
  • Pennsylvania Rare -- A classification of plant species which are uncommon within this commonwealth because they may be found in restricted geographic areas or in low numbers throughout this commonwealth.
  • Pennsylvania Threatened -- A classification of plant species which may become endangered throughout most or all of their natural range within this commonwealth, if critical habitat is not maintained to prevent their further decline in this commonwealth, or if the species is greatly exploited by man.
  • Pennsylvania Vulnerable -- A classification of plant species which are in danger of population decline within this commonwealth because of their beauty, economic value, use as a cultivar or other factors which indicate that persons may seek to remove these species from their native habitats.
  • Special Concern Population -- A classification that is composed of colonies, groups or single individuals of a plant species that the department has determined to be a unique occurrence deserving protection. Among the factors that may be used to classify a plant population within this category are the existence of unusual geographic locations, unisexual populations or extraordinarily diverse plant populations.
  • Tentatively Undetermined -- A classification of plant species which are believed to be in danger of population decline, but which cannot presently be included within another classification due to taxonomic uncertainties, limited evidence within historical records or insufficient data.
  • Unlisted -- Plant species which are native to this commonwealth, presently capable of sustaining their populations successfully, not in need of protection currently and currently not included in classifications under this chapter.
  • Wild Plants -- Naturally occurring native flora, except those commonly considered an agricultural commodity, including green and non-green species or subspecies, variety or a part, product, seed or progeny thereof.

What can you do at home?

There are some things you can do at home to help native wild plants.

First, leave native wild plants where they are. Picking flowers means the plant will not go to seed. For plants with very few individual, this can be detrimental. Take pictures, but leave the flowers in their habitats.

Do not remove plants from the wild to plant home. They generally will not survive and it removing them hurts their natural populations.

You can also help by identifying invasive plants and removing them at home. This will prevent the spread of invasives to other areas.

Also, by choosing a native species suited to your site conditions, you can get the right plant in the right place.

You can also get involved in local friends’ groups that help by maintaining parks and trails or removing invasives.

Tell your friends about native landscaping and the importance of plants in our everyday lives -- conservation begins at home.