Invasive Species

See also Ticks, Stiltgrass, and Crows

Even with DNA detection, Asian carp continue to evade scientists, Salon, March 15, 2020Part of the problem with Asian carp is the difficulty catching them. When things change on the very edge of their territory, where the fish are sparser. At low abundances, they evade nets, as well as the electrical currents biologists sometimes use to temporarily stun and catch the creatures.
The team took samples throughout, and following everyone’s initial surprise that the method worked, they found Asian carp DNA much closer to Lake Michigan than anyone had anticipated. Soon Michigan filed a lawsuit against the State of Illinois, demanding the closure of two shipping locks near Chicago, a move that could have decimated the city’s shipping industry. (Neighboring states joined Michigan in its fight, but in the end, the waterways remained open and so far, Asian carp haven’t established populations in the Great Lakes.)
The case never made it to court, but scientists still found themselves caught in the middle of a political battle with huge economic consequences.

Lesser Celandine is on the rise, Ohio Country Journal, March 13, 2019Lesser Celandine (Ranunculus ficaria = Ficaria verna) plants are starting to rise in southern Ohio. This non-native is known as a “spring ephemeral” owing to the time of year when the short-lived plants and flowers are present. It is beautiful unless you consider that the magic carpet rolls over native spring wildflowers. Although lesser celandine plants seldom rise more than 4 to five inches above the soil, they have dense root systems and plants grow together to form mat-like impenetrable canopies. I’ve observed lesser celandine rolling over Trillium (Trillium spp.), mayapple (Podophyllum peltatum), cutleaf toothwort (Cardamine concatenate), Dutchman’s breeches (Dicentra cucullaria) and Virginia springbeauty (Claytonia virginica).
Bulbils can give rise to new plants and are perfectly suited for being picked-up in the dew claws of deer. Indeed, deer are a major mover of lesser celandine and play a pivotal role in carrying this invasive plant to new locations.

Canada geese are as annoying as hell. In Alpena, that’s a death sentence, The Bridge, Sept 11, 2018The City Council voted 4-0 to approve the 2018 hunt. Folks with the local wildlife sanctuary, which protects a 500-acre waterfront area, are not upset. They’re more worried about invasive plants choking off the existing wildlife. “People realize (the geese) can be very messy,” said Roger Witherbee, a member of the sanctuary board who said he’s not heard anyone complain about the hunt.

Landscape Features Associated With Blacklegged Tick (Acari: Ixodidae) Density and Tick-Borne Pathogen Prevalence at Multiple Spatial Scales in Central New York State, Journal of Medical Entomology, July 18, 2018Blacklegged ticks are the most commonly encountered and medically relevant tick species in New York State and have exhibited recent geographic range expansion. Forests and adjacent habitat are important determinants of I. scapularis density and may influence tick-borne pathogen prevalence. We examined how percent forest cover, dominant land cover type, and habitat type influenced I. scapularis nymph and adult density, and associated tick-borne pathogen prevalence, in an inland Lyme-emergent region of NY. I. scapularis nymphs and adults were collected from edge and wooded habitats using tick drags at 16 sites in Onondaga County, NY in 2015 and 2016. A subsample of ticks from each site was tested for the presence of Borrelia burgdorferi, Borrelia miyamotoi, Anaplasma phagocytophilum, and Babesia microti using a novel multiplex real-time polymerase chain reaction (PCR) assay, and deer tick virus using reverse transcription–PCR. Habitat type (wooded versus edge) was an important determinant of tick density; however. B.burgdorferi was the most commonly detected pathogen and was present in ticks from all sites. Ticks infected with A. phagocytophilum and B. miyamotoi were collected more often in urban environments. Similarity between B. burgdorferi prevalence in Onondaga County and hyperendemic areas of southeastern NY indicates a more rapid emergence than expected in a relatively naive region.

With few friends on Great Lakes, chorus grows for cormorant kills, The Bridge, Aug 15, 2018The view that double-crested cormorants are an invader that threaten the natural integrity of the ecosystem is a common sentiment in upper Michigan. Lethal control of the birds to protect wild fish was authorized by the U.S. government for many years ‒ though not through raccoon militias. The control reduced cormorants in the region by about two-thirds. Anglers and congressmen are now renewing calls for lethal force. On Thursday, the federal agency is scheduled to host a meeting in Lansing with state and tribal officials to explore whether control is again needed in the Great Lakes to protect wild fish.

Gypsy moth caterpillar outbreak taking toll on Ann Arbor trees, MLink, July , 2018UM already is taking action to respond to what it considers the biggest gypsy moth caterpillar outbreak in 20 years, and the City Council took action this week to direct the city administrator to establish a monitoring plan and budget for a summer 2018 pheromone trapping effort to monitor the extent of gypsy moths in the city.

Pennsylvania may ban this popular landscaping shrub, Public Opinion, July 6, 2018Japanese barberry (Berberis thunbergii DC) is a prickly, hardy and cheap bush small oval leaves come in colors from green to purple. Deer won’t eat it and people won’t walk shortcuts through it. The thorny plant offers protection to deer mice, the primary winter host for deer ticks, which spread Lyme disease to humans. Barberry’s dense foliage also traps humidity that ticks need to stay active. A University of Connecticut study found in 2011 that the number of ticks carrying the Lyme spirochete were more than 10 times greater in barberry thickets than areas without the bushes.

Small dogs no match for coyotes in metro Detroit, attacks on the rise, Free Press, June 4, 2018There have been several reports in recent months of dogs being killed or suspected of being killed by coyotes in the metro Detroit area.

Browse by White-tailed Deer Decreases Cover and Growth of the Invasive Shrub, Lonicera maackii, Naturalist, Apirl 2018We found leaf frequency of L. maackii in two height ranges, 0.5–1 m and 1–1.5 m, was significantly greater where deer had been excluded for 4 y. Furthermore, the basal area growth of these shrubs over 5 y tended to be higher, and the final basal area of small shrubs was significantly higher, in exclosures. These findings, along with direct evidence of deer browse from the literature, indicate deer browse on this invasive shrub is sufficient to affect its architecture and growth, and potentially mitigate its negative effect on native plants. [abstract, pdf download]

White-tailed deer browse on an invasive shrub with extended leaf phenology meets assumptions of an apparent competition hypothesis, AoB Plants, Nov 2017We estimated L. maackii comprised 14–47 % of the annual deer diet. Deer browsed L. maackii each month, but consumption was high in early spring and late summer. Crude protein of leafy twigs of L. maackii in early spring was 12.9 %, much higher than leafless twigs of native species on-site. These findings support the assumptions of the hypothesis that invasive plants with ELP impact native plants via deer-mediated apparent competition.

Ideas for Your Nuisance Deer Conservation Program, Integrated Pest Management Insights. Nov 2017In New York State, if there is too much damage from deer, you could organize a nuisance deer removal program. This option is not available in all states. Fencing is another option. An eight-foot fence will keep out most deer from an area. Obviously, it is impractical to fence off a town.
There’s a popular myth that humans are invading deer territory. Wrong! The invention of the suburb created the perfect habitat for deer. Ecologists call deer an “edge” species, meaning they thrive in exactly the same kind of suburban landscapes people enjoy: lush gardens, wide open grass lawns, a diversity of flowering and fruiting plants and shrubs.10

‘Cute’ urban deer eat tons of vegetation, spread disease and damage ecosystems, Pittsburgh Post-Gazette, Nov 26, 2017 At a November meeting of Friends of Riverview Park, ecologist Tim Nuttle explained that the 251-acre public space, billed by the Pittsburgh Parks Conservancy as “a jewel of Pittsburgh’s North Side,” is being tarnished by an infestation of an aggressive invasive Asian worm. The worm destroys leaf litter, threatening the growth of new plants throughout the forest. A high density of white-tailed deer, which eat young plant shoots before their roots anchor to the ground and deposit waste that feeds the worms, is exacerbating the problem.

Fighting phragmites a never-ending battle, MLive, Aug 8, 2017Phragmites (frag-MY-teez) is an aggressive, invasive plant that grows to 15 feet in height and has had a massive impact on the ecological health of Michigan’s wetlands and coastal shoreline. Ever-expanding stands of the grass have crowded out thousands of acres of native plants across the state in recent decades, destroying food and shelter for wildlife, blocking natural shoreline views, and reducing access for swimming, fishing and hunting.

Fewer Deer, Less Garlic Mustard, Outside My Window, Dec 12, 2016It turns out that garlic mustard likes more sun than it normally gets in Pennsylvania’s summer woods so when deer over browse native plants their shade goes away and garlic mustard thrives.

Deer Discovery: Invasive Plants Get Boost from too Many Deer, Smithsonian Insider, May 6, 2016A survey of the two study plots after 25 years revealed the density of Japanese barberry, wine raspberry and Japanese stiltgrass was much higher in the open plot. The presence or absence of deer, they found, was an excellent predictor of the abundance of exotic plant species.

Deer Facilitate Invasive Plant Success in a Pennsylvania Forest Understory, Natural Areas Journal, 2009We suggest that deer-mediated disturbance to understory communities facilitates the success of invaders in forests. Many North American forests experience both exotic plant invasion and deer overabundance, but the two problems have never been empirically linked. In this paper, we quantify deer effects on native and exotic understory herbs in a western Pennsylvania forest.

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