Wildlife Corridor Project
By Ms. Hilary Joyner
With the growth of the Arizona population, many natural habitat areas have been increasingly introduced to highways, buildings, and other non-native animals. In order to encourage the reclamation of these habitats by their natural species, a Wildlife Corridor Plan may be implemented. These plans include designing and implementing a solution, recruiting local and government/county assistance, obtaining conservation easements to eliminate habitat fragmentation, and designing a wildlife conservation poster to raise awareness. There are six steps recommended in order to develop a solid solution: identifying habitat areas needing to be connected, selecting target species to evaluate, determining the relevant needs of each species, evaluating how the corridor could help the species, drawing a corridor map to ensure exact specifications, and developing a monitoring program. Even though in the photo below it looks like these animals are looking both ways, it doesn't mean they won't dart in front of a car when it approaches. This is the problem we are facing, and finding a solution for.
Wild animals trying to make it across the road.
Procedure
The first step in determining a Wildlife Corridor is to identify and observe two wildlife habitat areas that once were connected and are now spatial. These areas are known to be causing habitat fragmentation. For this project, two such areas were located at the edge of the national forest, south of Wilhoit, Arizona. Area number one (Area 1) consists of a space bordered on one side by homes and on the other side by highways. Area number two (Area 2) is bordered on one side by a highway and on two other sides by homes.
Area 1
Photo by: Jay Bostwick
Area 2
Photo by: Jay Bostwick
These areas are separated by various abiotic items: a highway, which has virtually extirpated the genetic interchange, and several ecotonal features in both areas, such as rocks, bushes, fences, and trees. Currently, there are not any landscape linkages in order for the species to migrate to spread their genes. Traveling along the highway between the two areas, several carcasses are seen along the ditch line. Further inspection shows there are no culverts or other avenues allowing animals to cross the highway in a safe manner. In addition, highway maintenance crews mow along the thoroughfare on a regular basis, which does not allow any natural habitat for the species to grow. When one considers that the animals habitat is removed from the highway proximity, you would see that this is better for the animals that habitat the area. Though there are no impediments to movement, these areas are excellent for habitation.
Potential danger area
Google Earth Image
The second and third steps of the Wildlife Corridor are to design the restoration of landscape linkages for a certain demographic, in this case large numbers of rabbits (Lepus capensis) and Javelina (wild pigs, Pecari tajacu)and evaluate their needs.
The intention is to restore the wildlife corridor and alleviate the current habitat fragmentation. Rejoining the two areas will allow for better breeding opportunities, reducing inbreeding, better the possibility of migration, make travel safer, allow for better foraging opportunities, and improve vegetation. Javelina tend to cross the highway as well as crossing land belonging to humans, which places them in danger from being struck by vehicles on the highway, traps set by landowners, or gunfire from landowners protecting their land. Rabbits also cross the highway and are struck by vehicles, poisoned in the summer by chemicals that landowners put on their gardens to protect from insects and disease, and shot by hunters or landowners. Providing safe passage using culverts, which the conservation committee can petition the highway department to install and maintain, and constructing conservation easements will reduce the deaths of these animals by a large percentage. Encouraging each homeowner to allow an easement for the animals that the landowner would maintain to aid the animals would also enhance this design.
Wild Rabbits
Javelina
As many of the community members already have a maintained area along the proposed landscape linkage, this should not be an impediment to the plan. In addition, most homeowners have motion sensitive lighting that remains lit for a very short time during the night, which will address concerns regarding light pollution. As part of implementing the Wildlife Corridor, wildlife awareness signage will be posted along the property lines and maintained by the county. The committee would also consult with the county animal control for tips and suggestions to ensure that proposed actions would adhere to county policies. By achieving a well centered operation, the plan will maximize the protection of the native animal species in this area. Using an adaptive management approach, the committee will attempt to make this area safer for the animals, increase opportunities for them, and make the wild land area a better place overall.
Example of an overpass corridor
The goal of the proposed corridor is to eliminate the impediments to movement, exacerbate the genetic interchange, and allow better access to conservation easements. To do this, the corridor will consist of two 2 foot culverts and two 4 foot culverts that will allow housing for large animals like Javelina (Pecari tajacu) and Whitetail Deer (Odocoileus hemionus) as well as providing safe passage for other native species. The smaller culverts are aimed at housing and providing passage for smaller species like rabbits (Lepus capensis), squirrels (Scirius arizonensis), and birds, such as quail (Lophortyx Gambelii). The four foot culverts are to be spaced approximately 1000 yards apart ( 900 meters, approx.) and extend from the roadbed at least three feet. The smaller culverts are to be set in the bottom of the larger culverts in material and secured in place with cement along the bottom. The overall length of smaller culverts shall be six feet, allowing for 2 foot extended past the larger culvert.
What I am proposing we do in Wilhoit, not quite so big.
Once the culverts are placed, and the smaller culverts placed inside the larger culverts and secured with gravel and cement, the animals will have increased shelter and safe passage opportunities across the highways. This will make rendering their offspring easier and safer for these animals. The demographic will be able to mix with a greater number of potential mates, which discourages inbreeding, reduces habitat fragmentation, and spatial disconnection over a temporal period. In addition, the project is designed to reduce abiotic barriers, allow for diversity in breeding selection, and reduce the distances needed to traverse the 0.5 mile (max) migration distances with the installation of the culverts. The genetic interchange would be greatly increased, expanding the core habitat, mitigating expiration of the umbrella species, and reducing the impediments to movement and allowing for an upswing of the birth rate. A benefit of increased interest in this conservation project is the ability for the group to manipulate the topography to extirpate restriction of movement as well as death rate using adaptive management. After execution of the agreed procedures and improved participation of community members, this project would be considered an exemplary deployment of human resources and increase the bonds in the community as well as encouraging the corridor to become a community asset.
Results
A successful Wildlife Corridor Plan, developing a monitoring program that is simple and easy to maintain.
Map by: Jay Bostwick
The Wildlife Corridor Plan as outlined would help improve the animals’ native to this area in many ways. Unrestricted access between the two areas will result in an increase in the population, a decrease in animal deaths, and more options at the height of the breeding cycle, therefore, reducing the chances of inbreeding. Additionally, benefits to the animals would include increased areas to roam and house themselves, more opportunities to forage for food, and safe passage across the highway. An opportunity to make a difference, get involved in a local project, and speak to fellow community members concerning their opinions will improve relationships in the community and help increase the emphasis on conservation and protection of animal species through adaptive management. All in all, it would be a win/win situation and a “feel good” project.
For this Wildlife Corridor Plan, the intended public watchdog poster can be seen in the figure below. Included are photos of the area that are to be protected by individuals who live adjacent to the wild land areas, as well as all members of the community. The main goal is to achieve participation from people who will help manage and enforce policies that protect the areas as well as allow for growth and adaptive management.
Photos by: Jay Bostwick
Sources/References:
Monica Bond's Principles of Wildlife Corridor Design
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