By Alex Schlueter & Ingrid Schneider
What is emerald ash borer?
Emerald ash borer (EAB) is an invasive species native to Asia and eastern Russia that threatens the ash component of all North American forests. There are 16 ash trees native to North America and their ranges cover much of Southeast Canada, some of northeastern Mexico, and the entire eastern U.S., plus pockets in the Southwest and California. Emerald ash borer preys almost exclusively on ash. Although it was discovered in 2002 near Detroit, MI it likely arrived in the early 1990s via shipping crates. As of May 2015, EAB has been confirmed in 24 states and two Canadian provinces. In Minnesota, as of May 2015, it has been confirmed in Ramsey, Hennepin, Winona, Houston, Olmsted, Anoka, Dakota, and Fillmore counties.
Although EAB adults do feed on the foliage of ash trees, defoliation is not the cause of ash mortality. Rather, EAB lays its eggs under the bark of the ash. When the eggs hatch, EAB larvae feed on the bark, creating tunnels that eventually cut off nutrients to the rest of the tree. It typically takes 1-6 years after infestation for ash to succumb to EAB.
This study was about EAB and public preference for how it is managed. Specifically, it was an on-site survey of visitors to one Minnesota state park to see how acceptable they found different management approaches that seek to slow spread of EAB. There is a general consensus among scientists that eradicating EAB is no longer feasible, but these techniques are often used by municipalities, public agencies, private land managers, and other entities to slow it down. By slowing its spread, more time is available to prepare for EAB infestation and associated ash mortality. Our main study question focused on how acceptable visitors find each of eight EAB management approaches. We chose to split this question into two areas, use and natural (represented on handout as pictures of picnic shelter and primitive shoreline, respectively).
The survey further included a general management question (“should EAB be managed on public recreational lands?”), a knowledge question (“How knowledgeable are you about EAB?”), questions about respondent characteristics (e.g. age, education, etc.), and others.
Wild River State Park in Center City, MN was chosen as the study site based on its ash cover, location about 50 miles from the nearest confirmed EAB location, and research availability.
EAB management approaches
We focused on eight approaches, summarized in Figure 1. This graphic is the same handout that informed respondents of the EAB management approaches.
Why visitor opinions and perceptions matter
One may ask why we care what the public thinks about these management approaches. Can we not just leave these decisions up to biologists and managers? First of all, the public is the customer. If public land managers implement strategies that are unacceptable to the visitor, then support for the management agency as well as for the resource itself will likely suffer.
Second, the public often has justifiable concerns that need to be heard by the scientific community prior to actions being taken. Very little research has been done on the social implications of EAB management, but the one published scientific study on the topic focused on an early effort by a Canadian agency to cut a 10-km wide swath of ash across a peninsula on public and private land, theoretically eliminating possible EAB hosts and creating a barrier to EAB spread. The plan was very controversial and was met with much public discontent due to its lack of stakeholder involvement. It was also ineffective, as it was later shown that EAB had established on the far side of the ash-free zone prior to the cutting.
We approached 542 visitors and 355 of them completed the survey, making our response rate 65.5%. Respondents strongly supported EAB management with 85.3% agreeing that EAB should be managed on public recreational land. A few people said it should not be managed (2.6%) and some did not know (12.1%).
Five of the eight management approaches were deemed acceptable by respondents, meaning that each had a mean acceptance rating above 3.0 on a scale of 1 being very unacceptable to 5 being very acceptable (Figure 2). The acceptable management approaches included wood regulations, sanitation cutting, progressive thinning, biological control, and creating sinks. Three management approaches were unacceptable (mean < 3.0): chemical treatment, complete harvest, and doing nothing. With the exception of biological control, the acceptance rating of each EAB management approach was significantly different between use and natural areas.
Visitors considered themselves fairly knowledgeable about EAB. While few respondents knew a lot about EAB
(4.8%), the majority had some knowledge of it (64.8%) and 23.6% had at least heard of EAB (Figure 3).
What do the results mean for management?
There are many ways that public land managers can use the data collected in this study, but the first conclusion is obvious. We need to do something about EAB! Doing nothing was less acceptable than every other management option and less than 3% of visitors said that EAB should not be managed on public recreational land.
Second, managers can use acceptance ratings as a straightforward way of determining visitor support (or lack thereof) for EAB management approaches they are considering. The data from this study in one state park, however, will not be directly applicable to all recreation areas that are threatened by EAB. Managers have to further consider how their area and visitor population differ from the study site, as well as differences within their recreation area as seven of eight EAB management approaches were significantly different in acceptance ratings between use and natural areas. As far as we know, though, no similar data on public preferences for EAB management exist. Therefore, this study serves as a good foundation to better understand public perceptions on the topic.
Lastly, we learned that visitors are quite knowledgeable on the topic. Over 93% of visitors had at least heard of EAB and considering that over 85% agree it should be managed on public recreational land, it seems we can suggest that most visitors know about EAB and know that it may have negative effects on their recreational experience. This shows that efforts to increase awareness in this region have been effective. Beyond that surface level, however, we do not know the content of visitors’ knowledge. Do they know what approaches are being used to fight EAB spread? Do they know where EAB currently is? Since awareness is high in this region, moving beyond simply getting the word out about EAB and instead informing the public about available or chosen EAB management approaches may be a logical next step.
Beyond the statistics and what might be next
On-site surveys are inherently time consuming and labor intensive. Other options such as internet questionnaires that reduce time to find respondents and eliminate data entry are faster and less labor intensive. However, talking to visitors at the site was beneficial in ways I had not considered when developing our research plan. As a researcher, I really appreciated how surveying on-site granted me an opportunity to further interact with respondents beyond what their survey responses might tell me. The thing that really stuck out to me was how many, and how deeply, these people cared about the topic and about specific ash trees. I can’t count how many people told me a story of the beautiful ash in their neighbor’s yard that was a tragic victim to EAB, reminisced about the ash they used to climb at their grandparents’ home as a child, or voiced very real concerns about the ash they currently cherish in their own yard.
In these informal conversations, I also learned a bit about some of the respondents’ reasoning for their preferences. I noticed, for example, that numerous people brought up biological control and how it has failed in the past. Many of these people were older and remembered personally witnessing these failures. For this reason, I compared preferences between three different generations. My hypothesis that preferences would differ between generations, more specifically acceptance of biological control, was not supported by the statistics. In fact, there was little statistically significant variation between groups on any management approach. However, I do believe that in order to fully understand how the visitors feel about EAB management approaches, we need to further explore the reasoning behind their preferences. This might be better understood through qualitative interviews.
Another avenue for research is multiple study sites. Having only a single study site was a major limitation to this study. Future research should address sites across levels of infestation (unthreatened, threatened, infested, infested in the past) and geographic regions. Longitudinal research would also be helpful to understand changes in the visitor perspective as an area experiences and recovers from infestation.
For more information
Many quality resources exist on EAB. Perhaps chief among them is http://www.emeraldashborer.info/#sthash.CH1nDShG.dpbs, a wealth of information provided by a collaboration between numerous states and organizations. In Minnesota, forest pests are handled jointly by the Minnesota Department of Agriculture (MDA) and the Minnesota Department of Natural Resources (DNR). These two agencies provide EAB information at http://www.mda.state.mn.us/emeraldashborer and http://www.dnr.state.mn.us/invasives/terrestrialanimals/eab/index.html.
A poster summarizing results of tourist respondents (those that had traveled at least 50 miles) can be found at http://www.tourism.umn.edu/sites/tourism.umn.edu/files/postereabtouristacceptance.pdf.
About the Author
Alex Schlueter completed his Master of Science in natural resources science & management at the University of Minnesota in December 2014. His career goal is to be a Forest Supervisor with the USDA Forest Service or Park Superintendent with the National Park Service. Progressing toward this goal, Alex will be joining the Forest Service as a Presidential Management Fellow at the agency’s Washington, D.C. headquarters in October 2015. He will be a Natural Resources Specialist in the Office of Wilderness and Wild & Scenic Rivers. In his free time, Alex likes to hike trails, binge watch Netflix, and explore the city via his motorcycle.