What Are Eco Bridges/Wildlife Corridors and How Do They Help With Biodiversity Management?
What is an Eco Bridge/Wildlife Corridor?
Wildlife corridors, also known as "eco-bridges," are areas of habitat that connect wildlife populations that would otherwise be separated by human activities or structures such as roads, other infrastructure development, or logging and farming. Practically speaking, a wildlife corridor is a link of wildlife habitat, generally made up from native vegetation, which joins two or more larger areas of similar wildlife habitat. Wildlife corridors play a very important role in maintaining connections between animal and plant populations that would otherwise be isolated and therefore at greater risk of local extinction. Eco-bridges may include: underpass tunnels, viaducts, and overpasses (mainly for large or herd-type animals); amphibian tunnels; fish ladders; Canopy bridge (especially for monkeys and squirrels), tunnels and culverts (for small mammals such as otters, hedgehogs, and badgers); green roofs (for butterflies and birds).
Why Do We Need Eco-Bridges?
Human activity and intervention in our natural environment leave fragmented patches of intact or relatively intact ecosystems whose ties with others are severed. If human activities continue in the area, those islands of biodiversity become even smaller and grow further apart putting the ecosystems at risk. This ultimately leads to a breakdown in the various ecological processes such as species migration, recycling of nutrients, pollination of plants and other natural functions required for ecosystem health. As a result, the habitat will suffer severe biodiversity decline and local extinction of sensitive species.
Animals may also suffer by not being able to access particular habitats. In times of drought, roads can prohibit animals from reaching water.
Further, when animals cross roads, mortality is often the result. This rate of mortality can severely threaten animals and has been identified as a leading cause of the decline in some populations.
In such circumstances, wildlife corridors can help halt biodiversity loss and redress some of the impacts of the degradation and isolation of ecosystem.
Importance of Eco Bridges in Biodiversity Management
- To prevent genetic isolation of fragmented flora and fauna populations, the bridge would encourage the interaction of wildlife by facilitating movement between the once separated forests and effectively expand habitat, mating and foraging ranges of flora and fauna.
- With wildlife crossing the expressway from one nature reserve to another, the chances of pollination and dispersion of rare native plants could greatly increase.
- Eco-bridges would also bring about greater interaction between individuals leading to a healthy exchange of genetic materials, thereby reducing the occurrence of inbreeding and increasing the long-term survival of our native species.
- Providing crossing infrastructure at key points along transportation corridors is known to improve safety, reconnect habitats and restore wildlife movement. Throughout Europe, Asia, Australia and North America, wildlife crossing structures have been implemented with demonstrable success.
- Species that prefer natural areas (urban avoiders or urban adaptors) have not evolved as fast as the rapid pace of development. Thus, they prefer to remain within the natural areas or their edges. The species that prefer urban areas (urban exploiters) are usually different to those found in natural areas. Therefore, appropriate corridors for the dispersal of species are necessary to link between natural areas if they are far apart or isolated.
Challenges Involved with Eco Bridges
- The challenging aspects of wildlife corridors are the lack of funding because of the lack of research into the actual benefits of these corridors. Many organizations involved in spreading the word about wildlife corridors find it hard to generate a response.
- Wildlife corridors often need to be built towards a specific animal population which can decrease their efficiency in the grand scheme of conservation. A big horned sheep, for instance, might not cross a wildlife corridor built for that area’s bear population even though its migratory habits are similar.
- As many wildlife corridors intersect busy roads or places where a lot of humans are, many species shy away from the area. Corridors also need to be built very wide to maintain the wilderness effect, but this land is very hard to get approved for usage as a wildlife corridor in some cases.
- They also must maintain the same habitat as the areas the animals call home, or crossing will seem unnatural to the animals using the corridor. Unfortunately, these corridors often allow for the safe passage of invasive species of flora and fauna which can drastically change the ecosystem of a nearby area that was once inaccessible.
- More study needs to be conducted on specific animal migratory patterns as well as the overall benefits of these corridors in order to know if they are truly worth the cost of building and maintaining. In the meantime, the existing corridors should be taken care of and used as stepping stones for the future of localized animal conservation.
What Can be Done?
Overall corridor management should aim to ensure that ecological processes and corridor function are maximised:
- Maintain and increase vegetation cover and habitat quality to maximise connection between larger remnants of vegetation. This will help dispersal of wildlife populations between larger remnants and ensure genetic interchange and seasonal wildlife movement;
- Provide specific habitat resources and ecological needs, particularly for threatened species (e.g. Koalas);
- Maximise corridor width and function by revegetation and control of weeds and feral animals;
- Maximise the protection/linkage of landforms (i.e.. valley floors, floodplains, gullies, mid-slopes and ridges).