Many invasive plants introduce posionous compounds into the environment that inhibit the growth of native plants.  This phenonmenon is called alleopathy.  However, invasive plants can also change plant communities by introducing nutrients such as nitrogen.  And the effects can be significant.  That is the finding of a study done by a team of researchers from the universities of Bielefeld in Germany and Lisbon in Portugal.  Moreover, the area affected can be 3.5 times greater than the physical area covered by the exotic plant – in this case the leguminous shrub Acacia longifolia.  The article appears in Ecology Letters and is free.

CalWeedMapper is a new website for mapping invasive plant spread and planning regional management strategies. Users generate a report for their region that synthesizes information into three types of strategic opportunities: surveillance, eradication and containment. Land managers can use these reports to prioritize their invasive plant management, to coordinate at the landscape level (county or larger) and to justify funding requests. For some species, CalWeedMapper also provides maps of suitable range that show where a plant might be able to grow in the future. The system was developed by the California Invasive Plant Council and is designed to stay current by allowing users to edit data. 

The Calweedmapper website displays data on all 200 invasive plant species from Cal-IPC’s statewide Inventory.  These data combine two sources: interviews with invasive plant experts and occurrence information from Calflora and the Consortia of California Herbaria (CCH). The maps show abundance, spread and management status for each species, displayed by USGS quadrangle. 

Users can generate reports in pdf format based on a selected region or species. The Regional Management Opportunity Report provides a summary table of information for all plants that present opportunities for management in the selected region. The Regional Species Report provides a map that illustrates the plant’s spatial distribution in the region. These reports are designed to help land managers prioritize and fund their work. Cal-IPC is working with several regions to develop strategic management plans using the information from CalWeedMapper. Contact CAl-IPC at mapping@cal-ipc.org for more information.

This dynamic tool allows users to comment on and update abundance, spread and management information.  Also, any new occurrence data submitted to either Calflora or CCH will update the data in CalWeedMapper.  As a result, the maps will show current information.

To show where a given plant is most likely to spread, CalWeedMapper also displays suitable range based on climate. Computer models were used to generate suitable range for some plant species based on where they currently grow. The maps show the areas that contain suitable range based on climate conditions in 2010 and 2050. These maps can help land managers with climate adaptation planning and preparing for the movement of new invasive plants into their region.

Yes, there are!  Tarantulas, scorpions, and prickly pear cactus are native to glades in the Ozarks.  Missouri glades, which ecologists sometimes call sunlit islands in a forested sea, are areas of exposed bedrock in the Ozark woodlands that create their own hot, dry, desert-like microclimates and have their own unique mixture of species. 

Glades Cut at Tyson Research Center. Photo by Jon Wingo/DJM Ecological Services

Tiffany Knight, PhD, associate professor of biology in Arts & Sciences is leading the research.  This is a giant experiment at the Tyson Research Center, Washington University in St. Louis’ 2,000-acre outdoor laboratory for ecosystem studies.  The experiment will test three different variables in 32 glades with the goal of establishing best practices for restoring not just degraded glade habitats but degraded ecosystems in general. “We’re manipulating glade shape, we’re manipulating glade size, and we’re manipulating whether or not plant species are seeded or allowed to establish on their own,” Knight says. “Those are our three big treatments, and then we’ll judge the outcome by measuring the biodiversity and composition of plants.”

Knight plans to carry on the research for decades monitoring plant communities and in particular several rare species in the glade ecosystems.  Additional experiments will test the importance of plant and animal interactions on biodiversity, such as the impact of mammal and insect predation.  For more information see the University’s press release.

The Tree canopy in major cities has decreased by about 0.2 percent in recent years (mid-to-late 2000s).  This amounts to a loss of about 4 million trees a year.  This is the conclusion of an article, “Tree and Impervious Cover Change in U.S. Cities” by David J. Nowak and Eric J. Greenfield.  The article appears in the journal Urban Forestry & Urban Greening  (free access to full article).

Newell Park Oak Grove in Saint Paul Minnesota

As the study points out, ”trees provide various benefits associated with air and water quality, building energy conservation, cooler air temperatures, reductions in ultraviolet radiation, and many other environmental and social benefits.”  Trees therefore are vital to urban health and well-being.

Even in the one city where tree cover increased, Syracuse, the news was not necessarily good.  The tree canopy in Syracuse increased by one percent during the study period.  However, the increase was dominated by European buckthorn (Rhamnus cathertica), a nasty invasive tree/shrub.

There is now a forest “fire deficit in the Western United States. Human activities and ecological and climate changes have combined to

National Oceanic and Atmospheric Administration Image

contribute to this deficit. This is according to a recent study published in the Proceedings of the National Academy of Sciences: Long-Term Perspective on Wildfires in the Western USA.   (Free access to full article.)  The study was undertaken by an international twelve-member team.

The article observes that “fire regimes are primarily a product of climate, vegetation, topography, and human activities.”  These factors interact in a variety of ways.  One of these is the introduction of invasive plant species.

President Obama proposed to put 20,000 veterans to work over the next five years with a Veterans Job Corps conservation program.  The initiative would put up to 20,000 veterans back to work over the next five years "protecting and rebuilding America."  Specifically, as stated in a White House press release:  ”veterans will restore our great outdoors by providing visitor programs, restoring habitat, protecting cultural resources, eradicating invasive species, and operating facilities. Additionally, our veterans will help make a significant dent in the deferred maintenance of our Federal, State, local, and tribal lands including jobs that will repair and rehabilitate trails, roads, levees, recreation facilities and other assets. The program will serve all veterans, but will have a particular focus on post-9/11 veterans.”

This program harkens back of course to the Works Progress Adminstration (WPA) which spent about $40 million in the late 1930s and 1940s on work in the National Parks (about $650 million in 2012 dollars).

I will keep you posted on the progress of the Veterans Job Corp.

There are several recent articles and publications on the effects of fire on invasive plants.  Fire figures into ecosytem and invasive plant species management in two big ways. 

Wildland Fire

First, invasive plants can change the way an ecosystem responds to fire.  The September 2011 issue of the Journal of Rangeland Ecology & Management has six papers on the interplay between fire and invasive weeds in the cold desert regions of the western United States. One paper, for example, focuses on the Great Basin region and the spread of invasive cheatgrass among sagebrush sites.  Cheatgrass has invaded this area.  Because cheatgrass is fine-textured and matures early, fires have become more frequent.

Second, invasive plants can change the way an ecosystem is managed with fire.  Several publications have addressed the strategies behind using prescribed burns to control invasive plants.  See  Use of Fire as a Tool for Controlling Invasive Plants by Joseph M. DiTomaso, Matthew L. Brooks, Edith B. Allen, and Ralph Minnich Edited by Joseph M. DiTomaso and Douglas W. Johnson 2006 from the California Invasive Plant Council; Wildland Fire in Ecosystems: Fire and Nonnative Invasive Plants 2008; United States Fish and Wildlife Service, Fire Management and Invasive Plants: a Handbook 2011.

Dave may not be your stereotypical tree-hugger.  He doesn’t drive a Prius or sport a pony-tail.  He drives a Chevy pick-up and often wears deer hunter orange.  He worked a union job as a mechanic and

The pond at Southwood Nature Preserve

machinist at a car dealership and raised a family with his wife Donna. He served in the army during the Vietnam War.  He grew up in rural Minnesota putting himself through trade school while working at Hugo Feed

One acre oak savanna at Southwood Nature Preserve won a LEAP award for sound ecological management practicesEarth Day Volunteers on the old viewing platform at Southwood Nature Preserve

Mill.  Now in retirement, he’s a driving force behind a community effort to create one of the most successful nature preserves in the Twin Cities metro area – Southwood Nature Preserve in North St. Paul.  Dave and his family have a life-long love of nature and Southwood Nature Preserve is an expression of that love.

 In 2007 Dave and his daughter Carrie, a field biologist with U.S. Fisher and Wildlife, walked through what was then Southwood Park.  Buckthorn dominated the forest understory.  Giant knotweed and reed canary grass choked the pond.  A confusing web of unofficial trails burdened the ecosystem.   However, Carrie told her Dad that Southwood was a potential “gold mine.”  From that point on, Dave started mining.

 Four years later Southwood is transformed.  A one acre oak savanna with wildflowers replaced an old dump site for a roofing company.  A spacious viewing platform overlooks the pond with blue wing teal, green herons, great herons egrets, mallards and occasionally a bald eagle.  Great horned owls, bluebirds, Wood ducks and bats use their newly constructed homes.  Deer and wild turkeys wander through.  New signs are up and will soon provide wildlife education.

 Southwood also draws people: classes from Cowern elementary school across the street; cross-country runners and skiers, dog walkers who get free doggie

Volunteers on Earth Day 2009 on the old viewing platform

bags and who must keep their dogs on leash.  Steve Johnson a retired teacher holds classes on bird watching for the Audubon Society along with bug classes from time to time.

 Southwood has been a lot of hard work.  Dave, Donna, city workers, and volunteers galore have done one project after another.  It started with a major buckthorn pull for which Dave designed and welded eight buckthorn wrenches.  North Haven Church, Boy Scout troop 188 and North St. Paul High Jr. ROTC pitched in.  The City, at Dave’s urging, even hired a crew from the local workhouse. 

Dave Nelson handing a buckthorn gavel to Congresswoman Betty McCollum with a buckthorn gavel - a gift for President Obama for signing a bill strengthening the Endangered Species Act.

After the buckthorn removal, garlic mustard took off.   When the garlic mustard was almost ready to go to seed, Dave recruited an “emergency crew” from the North St. Paul chapter of the Jr. ROTC to pull garlic mustard on a rainy Saturday. Seven people including Dave and Donna have done “capstone” projects for their certification as Minnesota Master Naturalists. (Now, Dave is president of the North Metro Chapter of the Minnesota Master Naturalists.) Park Commissioner Dave Andren helped design and construct the viewing platform along with other volunteers).  Two scouts provided many hours of labor to the nature preserve earning their Eagle Scout badge.

Dave has also sought broader community and political support for the preserve and for stronger environmental protection more generally.  He has gone door-to-door recruiting volunteers and donors.  He handcrafted more than seventeen gavels made from buckthorn.  The buckthorn gavels can only be earned with a $200 contribution to a Southwood Preserve fund or as recognition for significant work for the environment.

If you go to Southwood Nature Preserve on a spring, summer, or fall day

Volunteers working at the new viewing platform at Southwood

you likely will find Dave and Donna working on something. If you do, be sure to interrupt them. There is only one thing Dave likes better than working at Southwood and that’s talking to visitors about Southwood.

common teasel - dispsacus fullonum - photo by Steve Dewey

I attended the Invasive Plant Symposium 2011 in Milwaukee, Wisconsin, on December 14 and 15.  The event was co-hosted by the North Central Weed Science Society.   I tried to take a step back and look at some of the overarching topics discussed in the talks:

Mapping – critical for early detection and management of invasive species.  EDDMapS, for example, is a nationwide effort to map invasive species distrubution. 

Invasion Vectors – roads, railroads, waterways, powerlines are all routes for the spread of invasive plants. 

Prevention (e.g., cleaning off seeds and propagules from equipment), detection, and early control can limit the spred. 

Cooperative Weed Management Areas – neighbors banding together to prevent, detect, and control invasive plants. 

Protecting Gems – native prairies, wetlands, and other ecosystems can’t just be islands.  Buffer zones around these areas are critical.

Urban Area Management – some of these sites are highly disturbed and altered.  But at every conference I have been to, someone talks about rare and endangered plants that exist right in cities like Milwaukee.

Best Practices – Guidelines for organizations (forestry, construction, utilities, etc.) on detecting and preventing the spread of invasive plants.

The symposium had a lot of energy and was not doom and gloom.  Groups like MIPN and IPAW operate on very tight budgets.  It was an impressive effort.

I have spent several great sessions working with a volunteer at a park just north of St. Paul treating Japanese knotweed (Fallopia japonica, syn. Polygonum cuspidatum, Reynoutria japonica).  This is an amazingly invasive plant.  It’s not surprising given it’s a pioneer species on the volcanic desert formed on the southeast slope of Mount Fuji.  Here is striking video from the BBC showing the superweed grew more than 1m-tall (3ft) in just three weeks.