Alissa Marturano
Assignment 7
1. For my project, I will attempt to find priority areas along Vermont highways for land
bridge development. More specifically, I want to use road kill data to determine which
highways have more collisions and if these highways have specific areas where more
collisions occur. I will also analyze the surroundings of these highways to find the best
place to build a land bridge. This could include narrowing in on land use around the
highways to find large forested areas where animals might live and then building a bridge
to connect two forest areas that surround the highway. This could also include analyzing
surrounding highway habitat for ecological hotspots, which may be home to most of the
roadkill in an area. I will determine which species of roadkill is most common so that I
can gear the placement and type of the bridges to best suit these specific animals’ needs. I
will also look at wildlife collisions from the driver’s point of view. I want to find
information on highway speed limits, traffic volumes, and the width of the highways to
see how numbers of collisions can be impacted by infrastructure and peoples’ behavior.
After I determine an area for land bridge placement, I want to use my analysis as a
foundation for changes in highway planning. I want to push for transportation and
conservation officials to work together in designing and maintaining highways, since
both open up new opportunities for roadkill depletion.
2. Literature Review
a. “Vermont Wildlife Linkage Habitat Analysis” by John Austin, Kevin Viani, and
Forrest Hammond.
This article does not show how GIS was used to find places for land bridges.
Instead, it describes how scientists went out into the field to determine animal
migration and traffic patterns in hopes of finding out where the most roadkill occurs
and why. They were able to create a GIS layer from the roadkill they collected data
on and also created two other data layers: Wildlife Linkage Habitats (highlights areas
of animal migration) and Wildlife Crossing Value (shows WLH at specific areas on a
highway). In order to create the WLH and the WCV layers, they mapped land
use/land cover, development density data, contiguous habitat data, and conserved
land data. Although this project does not take their results a step further to determine
areas for land bridge placement, it does describe some of the preliminary mapping I
will need to do to find my results. I thought it was important to know where my data
layers were coming from and what they mean, especially for the complex layers like
WLH and WCV.
http://www.aot.state.vt.us/TechServices/EnvPermit/Documents/Wildlife_Linkage_Ha
bitat_Report_5_15_06.pdf
b. Havlick, David. 2004. “Road Kill”. Conservation Magazine 5(1): 1.
This article describes how Daniel Smith from the University of Florida used
GIS mapping to find ‘ecological hotspots’ where high quality habitat, vehicles, and
animals intersect. He points out that not every road will show the same pattern of
collisions, and different sections of roads will be more deadly due to traffic
conditions and land characteristics surrounding the highway. Daniel Smith went out
into the field and tracked animal movement and collisions in his supposed hotspots
and found that his GIS model accurately highlighted areas of high animal migration.
Based off of his work, Florida transportation officials are building land bridges in
many of his hotspots. The article also points out that existing bridges that need to be
repaired or replaced are excellent sources for new land bridge constructions. It also
shows statistics that in Vermont from 1981-199, animal collisions caused $31
million in vehicle damage. Though this article did not go deep into the
methodology used, it did cause me to think of how we could take roadkill analysis
to a larger scale by implementing it in existing planning models.
http://www.conservationmagazine.org/articles/v5n1/road-kill/
c. Seaby M and Rivard D. 2004. Using geographic information system (GIS) technology
to study the impacts of roads on Canada’s national parks . IN: Proceedings of the
2003 International Conference on Ecology and Transportation, Eds. Irwin CL,
Garrett P, McDermott KP. Center for Transportation and the Environment, North
Carolina State University, Raleigh, NC: p. 669.
This article describes how Parks Canada used GIS to look at factors
influencing frequency of animal-vehicle collisions and identified various
mitigation measures. They found that physical characteristics of the highway, like
wide roads, and surrounding land, like good roadside habitat and water supply,
were the best criteria to determine high frequency roadkill sites. They also
determined that high traffic and high speed roads should be prioritized for land
bridge development over low traffic roads due to cost/benefit analysis. This paper
supports my opinions on land bridge placement, and it also made me think about
other forms of mitigation. I realized that we also need to mitigate with human
action, like decreasing speed in high animal traffic areas. It discussed the
placement of animal crossing signs, and how most of the time, they are not
located at high animal kill sites. If we move the signs, they may be more effective.
http://repositories.cdlib.org/jmie/roadeco/Seaby2003a/
d. C.F. Jaarsma, F. van Langevelde, J.M. Baveco, M. van Eupen, J. Arisz. 2007. Model
for rural transportation planning considering simulating mobility and traffic kills in the
badger Meles mele. Ecological Informatics 2(1): 73-82.
This paper demonstrates the applicability of GIS for combining ecological
conservation and highway planning. They specifically address the issue of the
endangered badger in the Netherlands and describe how GIS was needed to show the
badgers movement patterns as well as daily number of road crossings. They also included
traffic data and population sizes to determine how risky each road area is to badgers. The
authors really emphasize how important GIS is in this type of analysis. Again, this type
of analysis will be preliminary for my project, but it is still a huge part of narrowing
down areas for land bridge placement. I liked how this article included the concept of
changing planning outlooks to include ecological conservation, since that is the ultimate
goal of my project.
e. Other sites I will use:
http://www.tfhrc.gov/pubrds/marapr00/critters.htm- US Dept. of Transportation Stats
3. MethodsFirst, I will need to set up a base map of Vermont, which will include the state
boundary, county boundaries, hydrography, roads, and forested areas. Since I am
beginning my analysis by looking at the entire state, I will need data covering the entire
state, not just specific counties.
I will then put up my roadkill by species data, which will allow me to determine
which species are killed most often and which roads have the most collisions. From this
information, I will make new data layers from the highways with the most collisions and
species that are killed the most. It is important to know what species are killed the most,
because if they are large mammals as opposed to salamanders, different mitigation
projects will be needed.
After I determine which roads have the most collisions, I will have to look at the
surrounding areas of each highway for more insight into land bridge placement. I will
look for roadkill occurrence in ecological hotspots. In addition, I will look at land cover
around the highways to see if there are any spots that have forested areas on both sides of
the highway. I will also use land use to look for development around the highways so I
can avoid urban areas or those that are residential. Along those same lines, I will
determine population densities around the highways. I will also see if there are
recreational areas or bike trails in forested areas, so that people can benefit from land
bridge development as well. I could also look at deer wintering areas to see where they
congregate, and I will also need to look at WLH around the highways to see where
animals migrate the most.
Next, I will need to look at the road’s characteristics. I will need to identify areas
of the roads with high speed limits and with high traffic volumes. These areas are good
for land bridges because collisions are more likely to occur when there are more cars that
are going fast. In addition, I would like to see how wide the roads are. An animal has a
higher chance being killed on an 8 lane highway than on a 2 lane highway. I would also
like to see if a high WCV correlates to higher road kill numbers. To do this, I will
highlight areas of the roads that have a WCV greater than 8. If I find that collisions are
more likely to occur in areas with high WCV, I will definitely consider those areas when
I decide where to build the land bridge.
Finally, after I have pinpointed a specific area on a highway, I will check to see if
an overpasses or bridges already exist in the area. It is possible that some of the bridges
need to be repaired or aren’t being used that much anymore. It would be better to repair
an already existing bridge and convert it to a land bridge than to build one from scratch.
If I do need to build one, I will need to check elevation data to make sure that the slope is
high enough on the sides of the highway to be able to connect them with a land bridge.
4. I am considering using the following data layers:
Data Layer
Roadkill by Species
Ecological Hotspots
Source
VGCI
VGCI
Wildlife Crossing Value
Wildlife Linkage Habitat
(raster)
County Boundaries
VGCI
VGCI
Vermont State Boundary
VGCI
Hydrography
ESRI data maps (basemap)
or VGCI
Roads
Speed Limits
VGCI
Need Help
Traffic Volume
Highway Widths
Land Use
Land Cover (raster)
Elevation (50 ft contours)
Census Tracts 2000
Forest Data
Vermont Orthophoto
Deer Wintering Areas
Parcels
Urban Areas of Vermont
Housing Stats
Recreational/Trail Sites
Bridges
Need Help
Need Help
Need Help
VGCI
VGCI
VGCI
VGCI
VGCI
VGCI
VGCI
VGCI
VGCI
VGCI
VGCI
VGCI
Accuracy / Actual Accuracy
+/- 10-20 ft / +/- .5 miles
+/- 100-200 ft / (NMAS for
1:250,000)
+/- 10-20 ft / Not given
+/- 50-100 ft / Not given
+/- 50ft ( not important for
roadkill, but important for
implementing land bridge)/
Not given
+/-50-100ft depending on if
roadkill falls on a road on
the boundary/ Not given
+/- 100-200 ft (just need to
know that there is water in
the area) / +/- 15ft
+/- 10ft/ Not given
+/- 100-200 ft (just need a
general idea of how fast
people are going)
+/- 50ft
+/- 10 ft
+/- 50-100 ft/ not given
+/- 50-100 ft / not given
+/- 20 ft / +/- 40 ft
+/- 50-100 ft/ +/- 166.67ft
+/- 50-100 ft/ Not given
+/- 10 ft / +/- 15ft
+/- 20ft / +/- 40 ft
+/- 10-20 ft / Not given
+/- 50-100 ft/ Not given
+/- 50-100ft / Not given
+/- 20-50 ft / +/- 166.67ft
+/- 10 ft / +/- 15 ft
-The ones I need help in are either because I’m not sure of the name they would be called
in the Vermont database (speed limits, traffic volumes, highway widths) or because I just
cannot find them at VGCI (Land use).
-I feel like the accuracy of my data varies because, though the bridge placement will need
to be specific, it will be connecting large areas on either side of the highway. So, I will
just need to know if there are people or forest around an area, which doesn’t need to be
very specific. On the other hand, road data needs to be very accurate as well as bridge
placement and road kill sites.