Search

In 2010, the American organization ARC held an international competition to design a series of 25 wildlife crossings across highways to connect the southern and northern Rocky Mountains. Zwarts & Jansma Architects, in collaboration with OKRA landscape architects, Iv-Infra, and Sjef Jansen Plan Ecology, won 1 of the 5 finalists’ places with their “Landshape” design. For the designers and ecologists, the main challenge was to create a series of wildlife crossings that would be buildable, affordable, and adaptable to context. To meet the set criteria, the team made an important technical invention. They designed a repeatable, modular structure. For its construction, the team developed a flexible formwork, which can be used to create variable shells. The formwork is made of cable nets, over which a fabric (textile membrane) is placed. Its unique property is that the cable nets can be re-used many times in varying forms. The ecological composition of an area is the decisive factor in the composition of a wildlife crossing. The most important organizational feature of the architecture is the extrapolation of existing curves in the landscape. With “Landshape,” the team produced a physical entity that connects culture and nature. [ABSTRACT FROM AUTHOR]

The story of our crossing structure unfolds with an examination of the dramatic forces that drive wildlife movement biology and behavior, along with the adaptive response we have taken against the ecological variability inherent within the Colorado landscape. We have relied on scientific knowledge, site evidence, and information on regional wildlife populations to inspire our design. The questions we raised led us to closely examine animal anatomy, physiology, and behavior, and to imagine our design from an animal’s perspective. We set our sights, minds, and challenges on an evolutionary step in the design of an animal road crossing, not simply a bridge, but a new “species” in form and function. At the heart of our crossing structure is a three-dimensional module with a planted deck, piers, and protective edges. On repetition, the module can produce curved paths as well as linear ones that respond to the clues to animal movement through the terrain, their living landscape, and their reactions to light, color, and sound that have influenced our design. Our crossing structure presents a variety of conditions suitable for a wide array of species and is adaptable to different preferences for site and science. The connections made between areas on one side of the road and the other generate a footprint that is not only modular, but more importantly for scientific research, is site specific, minimally intrusive on the existing landscape, continually changeable, and aims to make the crossing free of stress for wildlife. [ABSTRACT FROM AUTHOR]

The Earth’s network of roads is vast and is reaching new regions with each year that passes. The effects of roads as barriers to animal movement and as conduits for other threats to the conservation of natural systems are well documented. Wildlife crossings can successfully mitigate some of the negative effects of roads by making it possible for wildlife to traverse even major highways safely. However, despite decades of successful deployment, the use of crossings remains uncommon. Their continuing rarity has a variety of origins, but cost and public appreciation of their benefits remain the most important limiting factors. We hypothesize that design can address both challenges. Here we describe a crossing design that is unconventional by current standards. We employ massed wood in a bridge crossing using laminated modules. These modules make it straightforward to customize the structure to its site while also keeping costs low, both because the materials are relatively inexpensive and because the need for specialized labor has been minimized. Other benefits include the rapidity with which the structure can be raised and the reduced need to close roadways during construction. Collectively, these innovations are intended to make crossings much less expensive and more easily adapted to a particular application. The use of massed wood creates a structure that is strong enough to support landscaping on its surface, is both weather- and fire-resistant, and that sequesters many tons of carbon in a long lasting structure. [ABSTRACT FROM AUTHOR]

Ecologists, landscape architects, and bridge and structural engineers do not work together often enough, and this paper illustrates the advantages of collaboration in the design of the next generation wildlife crossing. The process and details of collaboration are as unique as the solutions included in the award winning entry for the ARC International Wildlife Crossing Infrastructure Design Competition. This article illustrates the benefits of multidisciplinary collaboration, how ecological restoration was foundational to the design, and how all parties worked to develop a new and innovative highway crossing for wildlife. [ABSTRACT FROM AUTHOR]

The article discusses wildlife-vehicle collisions in North America with a focus on the increased construction of roads and the design of wildlife crossings within the context of a design competition for a wildlife crossing over Interstate 70 in Vail Pass, Colorado won by HNTB with Michael Van Valkenburgh & Associates.

In landscapes inundated with roads, wildlife is likely to negatively interact with vehicles during its lifetime. Wildlife crossing signs are easily deployed, cost-effective, and meant to encourage wildlife-friendly driving practices in hopes of reducing wildlife-vehicle collisions (WVCs) along roads. Here we use the placement of turtle crossing signs as a case study to provide recommendations for informed placement of mitigation structures across regional landscapes in Ontario and elsewhere. We collected relevant information (design, theft, and location) from 369 turtle crossing signs placed along roads. We then compiled turtle-vehicle collision data from various sources to statistically analyze where they occur in relation to habitat and road type. We also compared the locations of turtle crossing signs to validated hotspots, which was equivalent to 19,000 km of road in Southern Ontario. We found that at least 27% of signs were stolen and at least 10 different design types exist for crossing signs in Ontario. Thirteen percent of signs were not located at validated hotspots, and turtle-vehicle collisions occurred most often on paved highways and county roads. We conclude that a road mitigation strategy should accurately inventory where structures are located and monitor their effectiveness. Structures should be selectively placed using the best available information, such as metapopulation science and WVC data, especially in regions heavily fragmented by roads. In multi-jurisdictional regions, an effective strategy should also consider regional coordination that focuses on standardized sign design and information sharing in an adaptive approach. [ABSTRACT FROM AUTHOR]