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12 The concept and practical application of permeability might Scale-sensitivity considerations enter the picture because dif- best be understood by an example. Imagine a couple who live ferent animals have different movement capabilities and re- in a small town or suburb. They work close to their home and spond to the same landscape in very different ways. A mouse shop in the neighborhood. They have walking access to a gro- does not use or move across its home range in the same way a cery store, a church, a pharmacy, a movie theater, a medical moose does. Hence, an assessment of the local animal commu- clinic--in short, all of the amenities they need for a happy and nity that exists in the landscape that the road crosses is essential comfortable life. Then suppose that a major road that runs and will suggest different crossing types, configurations, and through the suburb is enhanced and made into a four-lane di- locations in order to achieve permeability in roaded land- vided interstate highway, with its accompanying fences and scapes. Understanding animal behavior is critical in achieving barriers, to accommodate the increased traffic and to provide permeability. the requisite and expected transportation services. Because of Providing guidance on the use and effectiveness of wildlife the location of the road, it now separates the imaginary couple crossings to mitigate habitat fragmentation and reduce the from their work and the amenities that they depended on and number of WVCs involves thinking in a large-scale, context- could access easily before. The couple, who always walked to sensitive framework that is based on sound ecological princi- access these amenities and resources, is now blocked by the ples. Connectivity is intimately linked to permeability. highway. The highway does, however, provide connectivity in Permeability is the goal of smart roads and intelligent mitiga- the form of crosswalks spaced approximately six to eight blocks tion. The goal for this research project is based on this prem- apart. The couple has a choice. They can either use their car and ise: understanding and establishing landscape permeability bear with the heavy traffic, or walk many more blocks to access guidelines that lead to effective landscape connectivity and the the crosswalks that would allow them to cross the road. It is restoration of ecosystem integrity--while continuing to unsafe for them to cross the highway in any place other than provide efficient and effective transportation infrastructure in the crosswalks provided. Their cohesive neighborhood is still a cost-effective economic manner. Research conducted for connected, but much less permeable. This is the critical difference this project was undertaken with the goal to evaluate how the between connectivity and permeability. Regardless of the selection, configuration, and location of crossing facilities can choice they make, the couple now find accessing the resources help restore landscape permeability as well as provide for they need for everyday life to be much more difficult and to improved motorist safety. entail much longer distances and a greater time commitment. According to Evink,79 motorist safety and the problems re- Although fanciful, this everyday urban situation is analogous to sulting from vehicular collisions with wildlife are important what happens to ecosystem resources for wildlife when high- concerns. Wildlifevehicle collision studies are used as an ways are built across natural landscapes. analytical guide to identify overall trends and problem areas Connectivity can be maintained by crossings, but the because collisions with larger animals can result in substan- placement, type, and configuration of the crossing will tial damage and personal injury. However, available datasets determine whether permeability is impacted. Think of cross- often do not include collisions with elk, moose, or caribou ings as a funnel that guides animals under or over roads. Then and seldom address collisions caused by "swerve to miss" imagine a context-sensitive road design that incorporates dif- responses by the driver, phenomena that will certainly in- ferent types and designs of crossings in appropriate locations. crease the valuation of damage caused by WVCs. There are The result can be thought of as a "sieve" that facilitates ani- serious methodological problems associated with current mal movement, rather than a "funnel." Connectivity evolves WVC research. The research of relevance to safety concerns to permeability. Restoring connectivity is a land-based con- addressed in this document use relevant data and models to cept and easy to understand. However, as can be seen by the identify collision-prone locations and to evaluate the safety example given previously, it is not necessarily equivalent with effectiveness of wildlife crossing measures. the idea of landscape permeability, which is an animal- centered concept. Research Approach The difference between the two concepts involves the idea of scale-sensitive (allometric), animal-based movement. Perme- The objectives of this project are to provide clearly written ability implies the ability of the animal to move across its home guidelines for: range or territory (its ecological neighborhood) in a relatively unhindered manner, i.e., movement ease can be indexed by es- The selection of crossing types, sentially a straight-line distance to resources. In scientific terms, Their configuration, the fractal measure of the pathway is non-tortuous and is of low Their appropriate location, dimension. Anything that hinders movement or increases dis- Monitoring and evaluation of crossing effectiveness, and tance moves the landscape in the direction of impermeability. Maintenance.