In cooperation with Utah State University and the Transportation Research Board, the United States Geologic Survey of Utah has crafted a website and decision guide regarding wildlife connectivity and roads. In their own words: "There is a core of 10 ecologists, engineers, and a webmaster that have made this site possible. These people in turn have worked with others who have assisted with this research. Our sponsoring organization, NCHRP of the National Academies oversees a panel of reviewers for this project as well." This decision guide provides recommended steps organizations should take when considering wildlife crossings, and is an invaluable resource that provokes analysis and reflection upon the site under question.
Today, I hope to follow the guide in a step by step identification process, note the minor details that may have been missed, and arrive with our project's own drafted action plan. Other components of the process include: resource evaluation, construction, and monitoring, but for now we will focus purely on identification, as an initial movement towards the potential of work on Interstate 89.
Step 1: Identify Species to Benefit from Potential Migration
While this step may appear to be one of the most basic, it is extremely important in the process as a whole. The presence of species in the region does not guarantee the movement of species across regions. Therefore, species identification depends greatly upon movement patterns, habitat needs, and behavioral issues associated with traffic and roads. Furthermore, one must consider more than just one or many populations. Considering communities and community interactions within more expansive ecosystems is extremely important. If a crossing is designed to favor deer crossings, but not coyotes, an great unbalance will be created causing more problems than one hoped to originally solve. The goal is to emulate natural processes to the greatest extent.
Identification of species is often done generally through behavioral commonalities throughout trophic levels. While this will never be an exact measurement, it is a good place to start. Herbivores, in our case moose and deer, are species that create necessary minimum measurements for crossings. We have been greatly considering an underpass toward the western region of our site, but were reminded by Ms. Rose Graves of behavioral patterns of ungulates. This site provides such a reminder as well. Why would any plant-feeding prey wish to enter a dark tunnel? Vulnerability is high. Therefore, it is clear our plan would have to involve necessary measurements of a larger, light-filled underpass. It is even more clear that more research is necessary regarding the measurements that would fit deer or moose populations here in Vermont.
Carnivores, in our case: coyotes, bobcats, and bears, also have been known to utilize underpasses, but require a smaller space than most ungulates. To find a compatible size for both predator and prey is the key opportunity that would allow populations from both trophic levels to pass. The site refers to success of this task in Banff National Park, Alberta, Canada with a few "select open underpasses".
Other creatures, such as small amphibians or small sized mammals, have historically required smaller, wet spaces devoid of human presence. While it seems the easiest task to create small tunneling culverts below the Interstate site, location of these tunnels and whether or not they would truly be utilized by smaller creatures is something that also requires further research.
One thing, however, is certain: with correct measurements and a compromise of space, species such as deer, moose, bobcat, coyote, and black bear should be able to utilize an underpass across I-89.
Step 2: Identify Ecological Processes
The most clear and apparent of all the ecological processes surrounding the site is the Winooski River. While some species of moose, deer, or bear would be likely to cross the water way, it is unlikely that smaller species such as bobcat or coyote would be as eager. There are, however, road crossings that are lifted from the water towards the far west and east of our site, and terrestrial species are also able to cross in more shallow locations of the river. In maintenance of the integrity of the project, I would claim any location where the river acts as a natural barrier is, in fact, just that - natural. It should not be tampered with.
Step 3: Identify Landscape and Topographic Features that May Affect Movement and Mitigation
This step requires understanding of each species individually. How animals approach a crossing is just as, if not more, important as how they choose to cross. Regarding the location of this site and the wildlife in question, forested areas to the south and north are extremely important for cover and access to the crossings. This places special emphasis on conservation efforts surrounding the region.
As the site mentions, guiding pathways such as lightly used trails (to start) would help populations find their way towards a potential crossing. Along these lines, placement of the crossing returns as an extremely important factor.
Another less prominent landscape feature of the land are the rocky outcroppings that sit between the lanes of the highway (See Site Visit post). These regions of the site might provide difficulty of underpass, but possibly the start of a smaller overpass that continues across the remaining lanes to the north. This is without a doubt one of the more hopeful aspects of this project and requires much further consideration.
Step 4: Identifying Engineering and Maintenance Concerns
These concerns are without a doubt some of the most important a project along the stretch of I-89 would end up dealing with. Consultations involving ecologists, civil engineers, transportation agents of the state, conservationists, and other financial supporters is completely necessary. Reasons why this project has continually been swept under the table in the past is due to costs, and it is undoubtedly going to be expensive. Bridges are known to be expensive projects of construction, then initiating/allowing flora to grow, and even underpasses would require a large effort to analyze and possibly even reconstruct sections of I-89 for stability. Other factors such as gradient of the road and gradient of the crossing are essential as well.
At this point, I would once again return to our conversation with Rose Graves and how my partners and I came to the conclusion that education of the land was completely necessary. No project this large comparatively to the state of Vermont can exist without overwhelming support and understanding.
Step 5: Weigh Cost Concerns With Potential Benefits
If cost wasn't enough of a problem, weighing it against the potential benefits of a project can be even more daunting. In a simple statement, the costs of constructing wildlife crossings, whether bridges or culverts, is expensive. It is in the millions, at best. As mentioned in a previous post, however, it's not necessarily impossible to accrue those funds, especially when considering federal money distributed between wildlife issues and the recent damage from Irene (the latter would have to incorporate the Winooski River and its buffers to great extent).
The real problem is understanding the issue well enough to know that it will actually work. The guide site reports on elk who refuse to pass through box culverts - 4 reported cases in 30 years! Teams and organizations working on this project will unfortunately find themselves wondering if they settle for cheap, efficient, and quick, intended populations will not use the crossing, the public will be furious with misallocated funds, and there will exist a useless crossing that is likely to deteriorate after years lacking careful monitoring.
The moral of this issue regarding wildlife crossing cost/benefit analysis: research extremely well, consult extremely well, construct extremely well, monitor extremely well. Projects such as these are too important to fail in the eyes of the public.
Step 6: Identify Appropriate Wildlife Crossing
At this point in the project, it is easy enough to rule out any form of "at-grade" wildlife crossings, which recommend only caution to the drivers and leave the danger up to the wildlife (or the drivers as well considering moose). Underpasses, however, are worth taking a look at, assuming wildlife bridges would be eliminated (for the time being) in a cost/benefit analysis.
Considering the table laid out by the decision guide, what is likely to work in our location is a Class 2 Medium Underpass. These underpasses would not be long, but short across a few lanes, tall enough to fit the height of where the highway is already raised, and accommodate most all species in question. The only exception might be the moose, which would find the passage too small. This is truly an issue that must be considered.
With these steps, our project hopes to set forth the initiation of further analysis and consideration for locations along our three-mile site. From a quick reflection of this work, it is all the more apparent how important education and true understanding of these ecological processes can be. We simply cannot allow ourselves to be contented with where we currently are, ignoring the possibilities of wildlife crossings, shunning the costs, and refusing to change.
It might be a challenge, but it is one I have come to realize so many people from several disciplines across North America hope to tackle. To that list, you can surely add three students here at the University of Vermont and their futures beyond it.
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For more information gathered by wildlifeandroads.org on work specific to the state of Vermont, please see: http://www.wildlifeandroads.org/search/search_results.cfm?state_prov=VT&Submit=Search
The site itself is also an invaluable resource and a great place to initiate any curiosity of wildlife crossings. Share it with others and always remember to consider how work and analysis all the way from Utah can be applied to a location near you.
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