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November 30, 2023

As the cool Northeastern U.S. warms, invasive plants are on the move. The Northeast Regional Invasive Species and Climate Change (RISCC) Network builds connections between resource managers and researchers to help create better invasive species management in the face of climate change. 

A nine-year-old boy holds a bundle of pulled herbs over his sholder
9-year-old Darrow Morelli pulling garlic mustard from the forest that surrounds his house.

There is a lot to love about the one-acre of land that surrounds Toni Lyn Morelli’s home. Part vegetable garden, part native wildflower meadow, part deciduous forest – it’s a pollinator’s paradise. It’s home to soccer balls and songbirds, raspberries and bobcats.  

As a Research Ecologist with the Northeast CASC, Morelli had long dreamed of having a wildlife-friendly garden of her own. And yet, like many homeowners, Morelli has weeds. Lots of weeds. She, occasionally joined by her 9-year-old son, spends many weekends fighting back two plants that threaten to take over her yard and the 40 acres of forest it abuts: waist-high patches of garlic mustard and heavy bittersweet vines. 

“We've been working on this one patch of garlic mustard for four years now,” says Morelli. “It has a two-year cycle, so you have to keep coming back and pulling it.” 

Garlic mustard and bittersweet are both invasive species, organisms that people have transported, either accidentally or deliberately, to a new place. To be considered “invasive,” a species must cause demonstrable harm in their new homes, for example by crowding out native plants, destroying wildlife habitat, or damaging human crops, landscaping or infrastructure. 

Invasive plants, by their nature, tend to be fast-growing, aggressive and resistant to regular weeding techniques. Once established, they can be nearly impossible to eradicate.  

“They're wreaking havoc ecologically, environmentally and economically,” Morelli says. “It's really pretty dramatic how much money is spent to deal with the damage done by invasive species.” 

It makes for an ongoing game of whack-a-mole. 

“I have a bad lower back from hours and hours of cutting bittersweet out of trees in my backyard,” says Bethany Bradley, Professor of Biogeography and Spatial Ecology in the Department of Environmental Conservation at UMass. “It will take down trees.” 

While Morelli and Bradley fight weeds at home, most of their time is spent thinking about invasive species on a much larger scale. Along with Carrie Brown-Lima, formerly at Cornell University’s New York Invasive Species Research Institute, they co-founded the Northeast Regional Invasive Species and Climate Change (RISCC) Network, an organization dedicated to improving invasive species management in the face of climate change. RISCC forms a crucial bridge between scientists and resource managers, helping to ensure that invasive species management is successful both now and in the future. It has since spread (invasive pun intended) across the country and sprouted four other RISCCs. 

“We bring invasive species managers, decision makers and researchers together to tackle the interface of these two huge global change problems,” Morelli says. 


Breaking Down Silos 

Cartoon graphic illustrating 6 mechanisms climate change helps invasive species spread, described in the caption
Climate change is impacting invasive species in many ways, including: Creating new pathways for invasive species to be introduced, such as new shipping routes that open up as sea ice retreats. Increasing CO2 levels, making some invasive plants more competitive and making herbicides less effective Causing range shifts as invasive species expand their range into habitats once too cool for them. Allowing earlier and longer emergence of pests due to extended growing seasons Creating new opportunities for invasions through extreme events like wildfires and hurricanes Graphic created by ORISE Fellow, Ben Slyngstad. 

The RISCC Network started as a chance encounter after Morelli and Brown-Lima met at a decision science training in 2016. In chatting about their day jobs, they realized that each had a key expertise the other was looking for. 

Brown-Lima explains, “Around 2015-16, we started hearing a lot of managers say, ‘We know that climate change is influencing invasive species, but we don't really know how, and we don't know how to incorporate that into our management and policy decisions.’” 

‘How can we manage invasive species in light of climate change?’  

“There wasn't a lot of synthesized information that could help managers make better decisions.” 

Through her role at the USGS, Morelli knew the science existed. She reached out to Bradley, an expert on invasive plants at UMass, and together with Brown-Lima they hatched a plan to get climate adaptation science into the hands of managers who need it. 

At first, Bradley was surprised that climate change effects on invasive species weren’t more well-known. She was well aware of the many ways in which climate change is causing invasive species to spread – how invasives are moving north following warming temperatures, how disturbances caused by extreme weather events and fires create footholds into new areas, how higher atmospheric carbon dioxide levels allow already weedy species to grow even faster.  

“The science was already pretty well established, so I kind of thought ‘what do they need me for?’,” Bradley says. “But what I learned from Carrie was that none of that science was known in the management community.”  

“It was like there was a complete barrier between science and management, in terms of getting that information out.” 

Like many fields, there is a historical divide between invasive species researchers and on-the-ground managers. Not from lack of interest in each other’s work – they just often work in different institutions, answer different questions, and have different goals. 

Morelli, Bradley, and Brown-Lima knew that had to change. 

“We realized we needed to start connecting researchers and managers,” Brown-Lima says. “We needed to create a platform to deliver information and to hear from managers about what they're actually doing.”  

“From there, the RISCC Network was born.” 


Bridging the Gap 

Today, the Northeast RISCC Network is made up of nearly 800 researchers, invasive species managers and policy makers from across the Northeast and even into Canada. 

The network serves three major functions: 1) creating connections among invasive species professionals, 2) getting published research into the hands of managers and policy makers and 3) producing new science to meet managers’ most pressing needs. 

The Northeast has few professional communities for invasion biologists, and none focused on the intersection of climate change, so it was critical to create spaces for managers to share insights across state lines. The RISCC team organizes webinars, workshops and annual symposia to allow RISCC members to learn from each other’s experiences.  

“We've created opportunities for people who've never met but are in similar roles across different states to connect and ask for advice,” Bradley says. “Learning from your neighbors is really important for climate-smart invasive species management.” 

The leadership team also summarizes existing research to help make it more accessible for managers and policy makers. The team writes summaries of academic articles that would otherwise be behind paywalls. They also create “Management Challenges,” two-page documents synthesizing everything known about a particular topic and giving clear management guidelines. They tailor these write-ups to cover high-priority topics of interest to the broader RISCC community, which they identify through surveys they send out to the RISCC listserv.  

These products, particularly the Management Challenges, are hugely popular. One Management Challenge has been downloaded over 4,000 times.  

Another function of the Northeast RISCC Network is producing original research. One of their main priorities: understanding which invasive species could be next for the Northeast. 

Climate models predict that the northeastern U.S. will resemble the warm and humid Southeast in the coming decades. For example, models from the National Oceanic and Atmospheric Administration (NOAA) forecast that New York City will have a similar average temperature to modern-day Charlotte, North Carolina by the end of the century. 

“The Northeast is predicted to be the hotspot in the country for invasive species, either range shifting from the South or coming over from other countries, as our climate gets warmer and wetter,” says Morelli.  


Oriental Bittersweet in a field
Bittersweet (Celastrus orbiculatus) is an aggressive invasive vine found across the northeastern US. Photo credit: Noel Pavlovic, USGS.
Green, leafy vines cover the trees, bushes and telephone poles on a hill outside of an apartment building
Kudzu (genus Pueraria) is an invasive vine found across the southeastern U.S. that is predicted to spread north due to climate change. Photo Credit: Jordan Bush, ORISE Fellow


In addition to new invaders, there is also the risk of so called “sleeper species.” Some invasive species can maintain small populations in areas that aren’t quite right for them – it may be a little too dry, or the winters a little too cold. But if climate change nudges the climate towards their ideal conditions, their populations can explode, suddenly becoming a big problem. 

RISCC scientists have generated publications, risk assessments and decision tools exploring future invasions in the Northeast. They have also leveraged their RISCC community to get this research into the hands of decision makers, informing invasive species management policies in New York, Maine and Massachusetts. 

“Here in New York, we have ‘prohibited’ and ‘regulated’ invasive species lists,” says Brown-Lima. “But most of those species are already here and widespread and it’s difficult to do anything about them. Now, [based on RISCC science], we're proactively listing species before they are introduced and become a problem, which is the best way to address it. 

“This was a great way to take the science, get it to the decision makers and turn that into real, effective decisions that proactively incorporate climate change into invasive species policies.” 


An Actionable Science Model 

Three woman smile at the camera.
(From left to right) Toni Lyn Morelli, Bethany Bradley, and Carrie Brown Lima at the RISCC Symposium in 2018.

The community has embraced the RISCC model. The Northeast RISCC listserv grows every year, as does participation in their online and in-person events. The Northeast network has also inspired similar initiatives across the country, with RISCC networks popping up in the Northwest, North Central, Southeast and Pacific Islands regions. There is even a budding RISCC in Canada! 

“We've had a lot of the same managers with us since day one,” Brown-Lima says. “They've learned a lot from us and taught us so much. It's been a very fruitful partnership.” 

“I'm so proud of the RISCC network. There are so many advancements that have come out of this collaboration.” 

One such manager is Julie Richburg, Lead Ecologist for Inland Natural Resources with the Trustees of Reservations in Massachusetts. She manages grassland, forest and wetland habitats protected by the Trustees and develops strategies to ensure the ecosystems remain healthy. A large part of her job is controlling a “never ending slew” of invasive plants, particularly in the grassland habitats.  

“Ever since I started working at The Trustees, climate change has always been a constant thought,” Richburg says. “I remember thinking that [the first RISCC conference] was such an important opportunity to look at both climate change and invasive species together.  

“It got me excited as a manager.” 

Richburg has participated in the network in many ways, including as part of the leadership team. She continues to attend their symposia, broadening her professional network and learning what is working (and not working) in other locations. She has sat in on subcommittees, helping to develop strategies to increase engagement with managers in non-profits like hers. And she uses RISCC products in her work. 

“I think RISCC is doing a really good job of thinking about new and diverse ways to reach out to managers,” she says. 

The success of RISCC can be boiled down to its core foundation: actionable science. The network is committed to creating and communicating science that is directly relevant to the on-the-ground needs of invasive species managers.  

This type of work is hard. It requires engaged, sustained partnerships and in-depth knowledge of the needs of potential users. 

“Being a bridging organization is a full-time job,” says Brown-Lima. “I don't feel like funders always take into account the amount of time it takes to bring people together and make collaborations work.” 

“That's why the CASCs are such a perfect fit for a RISCC initiative.” 

Through its one national and nine regional centers, the CASCs provide funding for researchers and natural resource managers to work together to address climate challenges. The network also employs scientists, like Morelli, to conduct actionable science research full-time. The Northeast CASC provides funding and personnel support to the Northeast RISCC Network.  

Since engaging with the CASCs through RISCC, Bradley has become more and more involved in the network. She now serves as the University Co-Director of the Northeast CASC. 

“It's just a very different model and one that I really like,” she says. “The CASCs want me to do science with a purpose. I feel like they are onto something awesome.” 

Brown-Lima has also since joined the CASC network. She left the New York Invasive Species Research Institute to be the Regional Administrator for the Northeast CASC in Fall 2023. 

“RISCC has driven me to better understand the importance of adapting to climate change,” she says. “It has brought to my attention that we need to think about climate change first, and other issues, like invasive species, are now falling under that umbrella.” 


A Transformative Experience 

RISCC has forever changed the way Bradley thinks about her science. 

“What I've come to learn is that what I had always thought of as ‘applied science’ was not actually useful, because I wasn't taking the extra step to make it useful,” she says. “I was ending with the publication and hoping that somebody would find it and use it.” 

“I love research. But RISCC to me is something that people actually need. It feels so rewarding, so we keep coming back.” 

Morelli feels RISCC’s transformative effects closer to home. She would often leave RISCC leadership meetings having learned about some new invasive species, and she would think, “I think I have that in my backyard.” 

Now, after years of sustained eradication efforts, she can see the benefits of her labor every day. 

“There's a whole section of my yard that used to be just garlic mustard and now we have these beautiful flowers. I've seen trees that would have come down but didn’t. There are more pollinators.”  

“I'm confident saying it's more diverse than it was before.” 

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