Conservation Science
Protecting Pennsylvania’s Plants and Animals
Invader Watch List
Many invasive species are exceptionally difficult and costly to control. That’s why it’s important to identify invasive species before they make their impact on the environment. To aid in early detection efforts, Pennsylvania Natural Heritage Program staff initiated a project in 2017 to determine invasive plants likely to arrive in Pennsylvania over the next ten years, species considered “emerging threats” to the commonwealth. The project identified 12 species, of which three are currently found in Pennsylvania, but are considered rare. The remaining nine species have yet to be found in Pennsylvania.
Aggressive invasive species can rapidly cause degradation of natural habitats and the decline of native species. For example, umbrella flatsedge (Cyperus diandrus) is considered imperiled in Pennsylvania. It grows on shorelines of ponds, lakes and streams, and in bogs and marshes. By finding and reporting invasive species such as purple loosestrife (Lythrum salicaria) and creeping Jenny (Lysimachia nummularia) that are known to inhabit similar places, you are aiding in the protection of this and other native rare plants that run the risk of being outcompeted by invasive species.
Preventing invasive populations from becoming established is the first line of defense in the conservation of native species that are rare and endangered. Armed with information about potential plant invaders, invasive species coordinators, land managers and citizen scientists can refine their invasive species survey priorities and be on the lookout for these emerging threats.
![Purple loosestrife Purple loosestrife. Photo by John D. Byrd, Mississippi State University, Bugwood.org, CC BY 3.0 US](https://waterlandlife.org/wp-content/uploads/2018/02/pnhp-purple-loosestrife-invsaive-species-photocredit-John-D.-Byrd-Mississippi-State-University-400x300.jpg)
Purple loosestrife
(Lythrum salicaria)
![Umbrella flatsedge, photo by Pete Woods. Umbrella flatsedge, photo by Pete Woods.](https://waterlandlife.org/wp-content/uploads/2018/02/pnhp-invasive-species-Umbrella-flatsedge_Cyperus-diandrus-Edinboro-Fen-PeteWoods-400x300.jpg)
Umbrella flatsedge
(Cyperus diandrus Torr.)
![Creeping Jenny, photo by Steve Grund. Creeping Jenny, photo by Steve Grund.](https://waterlandlife.org/wp-content/uploads/2018/02/pnhp-invasive-species-Creeping-Jenny-steve-grund-400x300.jpg)
Creeping Jenny
(Lysimachia nummularia)
Be On the Lookout
You can help us keep a watchful eye on these emerging threats. If you find any of these species, be sure to report your findings, including distinguishing photographs, to Pennsylvania iMapInvasives, which is managed by PNHP. This free online database accepts reports for invasive species from citizen scientists and natural resource professionals. We ensure that reports for high priority species are forwarded to state and local officials for quick management action to protect native species. You can download a brochure developed by PNHP staff, featuring profiles of invading plant species and the importance of early detection.
We have identified 28 invasive species that are emerging threats to Pennsylvania’s plants and animals. Many of these species are not yet present in the state, but have the potential to cause harm to the environment, economy or human health. With the help of many, we can preserve the future of Pennsylvania’s native ecosystems for the benefit and enjoyment of all.
![African Clawed Frog, Photo Credit: (c) Hendré via iNaturalist.org, some rights reserved (CC BY-NC)](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_African-Clawed-Frog@2x-700x525.jpg)
African clawed frog
![Alligatorweed, Photo Credit: Melissa McMasters via Flickr, "Alligator weed " (CC BY 2.0)](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_Alligatorweed@2x-700x525.jpg)
Alligatorweed
![Asian Longhorned Beetle, Photo Credit: Joe Boggs, Ohio State University, Bugwood.org (CC BY-NC 3.0 US)](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_Asian-Longhorned-Beetle@2x-700x525.jpg)
Asian longhorned beetle
![Asian spiderwort, photo by © Keith Bradley](https://waterlandlife.org/wp-content/uploads/2018/02/PNHP-WILDLIFE-INVADER-WATCH-LIST-Asian-spiderwort-Murdannia-keisak-Copyright-Keith-Bradley-400x300.jpg)
Asian spiderwort
![Asiatic sand sedge : photo by © Takahiro Yamaguchi](https://waterlandlife.org/wp-content/uploads/2018/05/PNHP-Invasive-Species-New-Asiatic-sand-sedge-400x300.jpg)
Asiatic sand sedge
![Blue Catfish, Photo Credit: User "rbairdpccam" via Flickr.com (CC BY-NC 2.0)](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_Blue-Catfish@2x-700x525.jpg)
Blue catfish
![Brown Widow Spider, Photo Credit (for both images): User "gcochrane13" via iNaturalist.org (CC BY-NC 4.0)](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_Brown-Widow-Spider@2x-700x525.jpg)
Brown widow
![Chinese privet, photo by © Sonnia Hill](https://waterlandlife.org/wp-content/uploads/2018/02/PNHP-WILDLIFE-INVADER-WATCH-LIST-Chinese-privet-Ligustrum-sinense-Copyright-Sonnia-Hill-400x300.jpg)
Chinese privet
![Cogon Grass, Photo Credit: Nancy Loewenstein, Auburn University, Bugwood.org (CC BY 3.0 US)](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_Cogon-grass@2x-700x525.jpg)
Cogon grass
![Diffuse knapweed - Photo by Matt Lavin, Montana State University, CC BY-SA 2.0](https://waterlandlife.org/wp-content/uploads/2018/02/PNHP-WILDLIFE-INVADER-WATCH-LIST-Diffuse-knapweed-Centaurea-diffusa-Copyright-Matt-Lavin-Montana-State-University-400x300.jpg)
Diffuse knapweed
![Dotted Duckweed, Photo Credit: Peter de Lange via iNaturalist (CC0 1.0)](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_Dotted-duckweed@2x-700x525.jpg)
Dotted duckweed
![Eurasian Water-milfoil, Photo by Alison Fox. University of Florida_Bugwood.org CCBY3.0_US](https://waterlandlife.org/wp-content/uploads/2020/10/EurasianWaterMilfoil_Photo_Alison_Fox_UniversityofFlorida_Bugwood.orgCCBY3.0_US400x300.jpg)
Eurasian water-milfoil
![Flattened Rush, Photo Credit: Ivan Tislenko via iNaturalist.org (CC BY-NC 4.0)](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_Flattened-rush@2x-700x525.jpg)
Flattened rush
![Garden Valerian, Photo Credit: Bart Busschots via Flickr, "Common Valerian" (CC BY-NC-ND 2.0)](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_Garden-valerian@2x-700x525.jpg)
Garden valerian
![Giant Reed, Photo Credit: Rebekah D. Wallace, University of Georgia, Bugwood.org (CC BY-NC 3.0 US)](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_Giant-reed@2x-700x525.jpg)
Giant reed
![Hardy kiwi wine, photo by Sten Porse, Bugwood.org, CC BY-NC 3.0 US](https://waterlandlife.org/wp-content/uploads/2018/02/hardy-kiwi-vine-invasive-species-PNHP-photocredit-Sten-Porse-400x300.jpg)
Hardy kiwi vine
![Indian Swampweed, Photo Credit: Shaun Winterton, Aquarium and Pond Plants of the World, Edition 3, USDA APHIS PPQ, Bugwood.org](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_Indian-swampweed@2x-700x525.jpg)
Indian swampweed
![Japanese Chaff Flower, Photo Credit: Rosemary Bauman via iNaturalist (CC BY-NC 4.0)](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_Japanese-chaff-flower@2x-700x525.jpg)
Japanese chaff flower
![Java waterdropwort, Photo Credit: LiCheng Shih via Flickr, "_ESL3410 Oenanthe javanica" (CC BY 2.0)](https://waterlandlife.org/wp-content/uploads/2018/02/java-dropwort-invasive-species-PNHP-photocredit-Erin-Stockschlaeder-400x300.jpg)
Java waterdropwort
![Leafy Spurge, Photo Credit: Lilia Efimtseva via iNaturalist (CC-BY-NC)](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_Leafy-spurge@2x-700x525.jpg)
Leafy spurge
![Leatherleaf Mahonia, Photo Credit: Robert Lyle Bolton via Flickr.com (CC BY 2.0)](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_Leatherleaf-mahonia@2x-700x525.jpg)
Leatherleaf mahonia
![Marsh thistle, Photo Credit: Peter Hanegraaf via Flickr, "Cirsium palustre” (CC BY-NC-ND 2.0)](https://waterlandlife.org/wp-content/uploads/2018/02/PNHP-WILDLIFE-INVADER-WATCH-LIST-Marsh-thistle-Cirsium-palustre-400x300.jpg)
Marsh thistle
![Nutria, Photo Credit: User "pilifv" via iNaturalist.org (CC BY-NC 4.0)](https://waterlandlife.org/wp-content/uploads/2023/01/WPC_Invasives_Invader-Watch-List_Nutria@2x-700x525.jpg)
Nutria
![Policeman's helmet - Photo by Joni Mäkinen](https://waterlandlife.org/wp-content/uploads/2019/02/PNHP-WILDLIFE-INVADER-WATCH-LIST-Policemans-helmet-Impatiens-glandulifera-400x300-1.jpg)
Policeman’s helmet
![Reed mannagrass, Photo Credit: Alexander Baransky via iNaturalist (CC-BY-NC)](https://waterlandlife.org/wp-content/uploads/2018/02/PNHP-WILDLIFE-INVADER-WATCH-LIST-Reed-mannagrass-Glyceria-maxima-400x300.jpg)
Reed mannagrass
![Swamp stonecrop - Photo by Sue Blanco White ©](https://waterlandlife.org/wp-content/uploads/2018/02/PNHP-WILDLIFE-INVADER-WATCH-LIST-Swamp-stonecrop-Crassula-helmsii-400x300.jpg)
Swamp stonecrop
![Water primrose, Photo Credit: Jardin des Plantes, Paris (CC BY-SA 3.0)](https://waterlandlife.org/wp-content/uploads/2018/02/PNHP-WILDLIFE-INVADER-WATCH-LIST-Water-primrose-Ludwigia-grandiflora-ssp-hexapetala-400x300.jpg)
Water primrose
![Water soldier, Photo Credit: Jörg Hempel, CC BY-SA 2.0](https://waterlandlife.org/wp-content/uploads/2018/02/PNHP-WILDLIFE-INVADER-WATCH-LIST-Water-soldier-Stratiotes-aloides-400x300.jpg)
Water soldier
For More Information:
Western Pennsylvania Conservancy
800 Waterfront Drive
Pittsburgh, PA 15222