Tallgrass Prairie - Threats to a Disappearing Ecosystem

Yesterday I told you about my plan for some sort of Tallgrass prairie restoration project in the Northwest corner of our property.

But why do we even need restoration? Why do we need prairie?

Did you know?

Over 500 exotic species of weeds have been introduced to North American over the last 240 years. 

And it’s not just non-native species. Canada Goldenrod is considered invasive when planning a tallgrass prairie because it will take over the ecosystem.

Why are these plants so invasive?

When they were brought from their original location, the natural creatures (wildlife, insects, bacteria, fungi, nematodes, etc.) that help control it were not brought along with it. Nothing eats it, nothing infects it, nothing kills it, so it spreads aggressively and takes over huge amounts of land. 

What non-native invaders may I have to battle?

Flowers and Grasses: 

• Spotted knapweed, Centaurea maculosa 

An invasive plant introduced to North America from Europe. It can establish large monocultures in grasslands which can cause a reduction in wildlife, a lowering of native biodiversity, and an alteration in soil nutrient composition.

• Knapweeds, Centuaurea sp. 

Spotted knapweed is highly invasive, and therefore can severely decrease the biological diversity of native habitats by degrading wildlife habitats, and hindering reforestation and landscape restoration efforts.

• Canada thistle, Cirsium arvense 

Heavy infestations growing in pasture can reduce native grass production by as much as 60 percent.

• Crown vetch, Coronilla varia 

Earliest report shows crownvetch in the United States in 1869. In the mid ‘30s it was commonly used to revegetate roadside cuts, mining sites, and railroad embankments. It was also planted as an ornamental and used as a cover crop or as green fertilizer. Then researchers started to notice that the rapid, dense growth can displace native plants limiting the success of prairie restoration. One report showed an attempt to restore a smooth brome (Bromus inermis) pasture to prairie. In 2002, the pasture was herbicide treated, plowed, and planted to prairie species. In 2003, crown vetch was present but only in trace amounts. By May 2005, crown vetch covered 46% of the restoration area, and the project was abandoned. When the project began, crown vetch was restricted to a ditchbank adjacent to the pasture. In another report one site had crown vetch spread 33 feet (10 m) outside of the planting area within 6 years of seeding. On an "extremely harsh" site, crown vetch spread to double the size of the seeded area. Because it forces a monoculture over a large area it has been shown to reduce insect abundance and diversity, even bee populations. 

• Wild carrot / Queen Anne’s lace, Daucus carota 

Will invade disturbed sites and quickly outcompete other species. It is a threat to native habitats if they are disturbed or newly restored, because it matures faster and grows larger than many native species. Fortunately, it tends to fade out as native grasses and forbs become established over time so hopefully it will not be a problem for long.

• Leafy spurge, Euphorbia esula 

Toxic to livestock. It’s extensive root system allows it to spread quickly and take much of the available water and nutrients needed by native plants. It will displace native plants in moist to dry prairies and savannas. 

• Sweet white clover, Melilotus alba

Brought as a forage crop and honey plant and quickly escaped. Native to Europe and Asia it was introduced to North America in the 17th century and is now widespread throughout Canada and the United States. It is a threat to endangered grassland and prairie habitats in Ontario and degrades these areas by out-competing native species. It is allelopathic, meaning the roots release chemicals into the soil which can prevent the growth of native plants. Yes, the honey bees may like it, but there are better suited native varieties to consider. 

• Yellow sweet clover, Melilotus officinalis 

Rapidly colonizes gravelly, well-drained soils such as roadsides, waste areas and river banks and bars. A single plant can produce 300,000 seeds and 80% of the seeds can survive after 30 years. 

• Phragmites / common reed, Phragmites communis 

A real threat in Ontario, this aggressive plant spreads quickly and out-competes native species for water and nutrients. It also releases toxins from its roots into the soil that can kill surrounding plants.

http://www.invadingspecies.com/invasive-phragmites/

Vines, Shrubs and Trees: 

• Oriental bittersweet, Celastrus orbiculatus 

Native to China, Korea and Japan it was brought to the United States in the mid 1800's as an ornamental plant and has since escaped and spread throughout the eastern US, Ontario, and Quebec. There are several threats this plant poses. One, it easily overruns native vegetation, forming nearly pure stands that can strangle shrubs and small trees and weaken or even kill mature trees. Two, it prolifically reproduces both by seed and by spreading its underground roots, which are capable of sprouting new stems. And three, there is also evidence that it can hybridize with the native American Bittersweet (C. scandens) which could result in the genetic elimination of American Bittersweet.

• Tartarian honeysuckle, Lonicera tatarica 

Don’t let it’s pretty red flowers fool you. This honeysuckle readily invades open woodlands, old fields, and other disturbed sites. Birds and mammals also cause it to spread rapidly, dispersing the seeds over wide areas. It can form an extremely dense understory thicket which can restrict native plant growth and tree seedling establishment.

http://www.invadingspecies.com/invasive-honeysuckles/

• Scotch pine / Scots pine, Pinus sylvestris 

Brought over in the ‘20s and ‘30s to deal with erosion control this is now a tree of choice for elimination from protected lands of the Nature Conservancy of Canada. Because this pine spreads like a weed it has invaded many natural areas, particularly grasslands. 

• European buckthorn, Rhamnus cathartica and Glossy buckthorn, Rhamnus frangula

So many problems with these buckthorn varieties. European buckthorn hosts a fungus that can reduce oat and barley yields. Forming dense bushes, they crowd out native species and use up valuable resources. Birds eat the berries, spreading the seeds over a wide area. Pull seedlings as soon as you find them and get as much of the root as possible. Once they get established, they are very hard to remove. 

https://www.ontarioinvasiveplants.ca/wp-content/uploads/2016/06/OIPC_BMP_Buckthorn.pdf

• Black locust, Robina pseudoacacia 

Creating a dense monoculture they aggressively invade dry and nutrient-poor sites and lowlands, outcompeting native plants and forming dense colonies that shade-out native flora. If you want a locust tree plant Honey Locust instead. Though rare now in Ontario this is their habitat.

https://www.ontarioinvasiveplants.ca/wp-content/uploads/2016/06/Black_Locust_BMP.pdf

• Dog-strangling vine, Vincetoxicum rossicum

Native plants and young trees are completely crowded out by the dense stands overwhelming them. Because it appears similar to milkweed, Monarch butterflies will lay their eggs on the plant but the larvae can’t survive because there is no food for them to eat. 

http://www.invadingspecies.com/dog-strangling-vine/

We all love ornamental flowers. There are some imports that have thrilled gardeners for years, and have not spread and taken over native habitat.

The problem is many varieties brought over for one reason or another have now started to destroy the plants that were originally here.  

I’m not talking about assisted migration. They haven’t just sashayed in, no harm done. They are taking over habitat once inhabited by another species and then displacing or extirpating the wildlife that relies on that plant species to survive. Wild lupines disappearing from Ontario meant the extirpation of the Karner Blue Butterfly. And that’s not all that has been lost.

Ontario no longer possesses

• Frosted Elfin Butterfly

  • Oak savannah, the Frosted Elfin’s preferred habitat is one of the most threatened habitats in eastern North America today. Like the Karner Blue, it depends on wild lupines, and as planted pines shaded out the lupins, destroying their home, the Frosted Elfin left Ontario completely.

• American Burying Beetle

  • Lost due to habitat alteration, the extinction of the Passenger Pigeon (which provided abundant carrion), attraction to artificial lights and predation.

• Eastern Persius Duskywing

  • Wild lupine and yellow indigo plants require open, sunny areas such as what was found in Ontario’s original savannah or barrens habitat. Unfortunately development has destroyed most of it along with encroaching woodland shading out the preferred habitat.

• Greater Prairie Chicken

  • As more and more land was cleared for agriculture in the early 1900s their habitat was lost. By 1920 they were no longer found in southern Ontario. By the ‘70s they were no longer found anywhere in Ontario.

• Eskimo Curlew

  • Habitat loss and fragmentation and a decline in food supply, especially grasshoppers, at spring migration stopover sites played a role in their extirpation.

• Blue Walleye

• Gravel Chub

  • Declined due to siltation and sedimentation of the Thames River from farmland runoff. Now declining throughout North America due to the same destruction of their habitat.

• Paddlefish

  • Overfishing, dam construction which has blocked access to spawning sites, dredging of channels and pollution.

• Lake Ontario Kiyi

• Blanchard’s Cricket Frog

  • Disappeared due to loss of wetlands due to development. Habitat degradation was also a factor since this frog does not tolerate pollution. Runoff of pesticides and fertilizers is believed to have been a major contributor to the disappearance of this species.

• Eastern Tiger Salamander

  • The main threats to this species are water pollution, fish stocking of lakes, and disease. Pesticide run-off into lakes and ponds is known to affect salamander development and survival.

• Spring Salamander

• Eastern Box Turtle

  • Over 100 years ago they were over-harvested for food and there was the extensive loss of forest cover in southern Ontario

• Timber Rattlesnake

  • People killed all the snakes they could find until there were no more.

• Illinois Tick Trefoil

  • Specifically disappeared due to conversion of tallgrass prairie to agriculture.

• Spring Blue-eyed Mary

  • Lost due to logging in its habitat.

The likelihood of an extirpated species coming back is unusual but it can happen. If habitat is restored, especially a corridor of it, then there may be enough food and shelter sources along the way for a species to come back. 

It’s like the Piping Plovers at Wasaga Beach. 

In 2007 when they showed up they hadn’t successfully nested here in 30 years. But then enough people protected the necessary area for them to breed and raise their young and here they are. 

Piping Plover, Wasaga Beach 2016

Isn’t that why so many people are planting something in their garden for pollinators?

They recognize that they can do something to help preserve the necessary ecosystem for the precious life that exists here. How beautiful that is!

I can’t wait for the snow to be off the ground so I can start preparing my Tallgrass Prairie patch. 

So what exactly is the plan?

See you tomorrow.