Driving down a long and windy road can sometimes feel like the best thing in the world: music cranked all the way up, windows down and the sun shining down on the world with the hills and trees lining the fields in the distance. This is a beautiful sight especially during the summertime, however, what about the the part of the land you’re driving on, now covered with tar? Most people don’t think of this when they’re driving, but roads have a huge ecological impact to the land they are implemented in; this in turn effects the environment and the wildlife living within the habitats of the land. Habitat fragmentation is a major issue when it comes to placing major transportation infrastructures (i.e., roads, highways, interstates, railroads, etc.) into the environment, but how do they exactly affect the land and the wildlife within it?
Impacts to the Land & Wildlife
Looking at the image above, what do you see? Roads cause a lot of fragmentation in the land, as you can see from the small patches of habitat in between the sections of crossing roads. A literature review I recently read about habitat fragmentation gave prime examples of how the land and wildlife are impacted by this. Habitat fragmentation is one the largest and most single pervasive threat to biodiversity across the world; it is the destruction of habitat, as well as altering and/or fragmenting large areas of habitat into smaller patches. Roads play a major role in habitat fragmentation because they cause a large dividing of the landscape into smaller patches of habitat; roads also cause interior habitat areas to turn into edge habitats, meaning areas in the interior of the land had characteristics unchanged and have now become altered and have edges that do not resemble what the habitat used to look like or be. As of 2003, 3.9 million miles of roads have caused direct habitat loss to our landscape in the U.S., and this has only increased with the number roads we currently have in the U.S. In terms of how habitat fragmentation affects wildlife populations and species, fragmentation forms the landscape to have altered habitats or areas that have developed fundamentally differently due to being shaped from natural disturbances, such as major transportation infrastructures; this is turn causes wildlife populations and species to adapt to these altered habitats over time.
These impacts of habitat fragmentation from roads have adverse effects to wildlife, and include, but are not limited to, the following: increased isolation of populations and species causing adverse effects on genetics and diversity, changes to vegetation the animals forage or feed on, changes to the quality and quantity of food, changes in temperature, changes in the flow of energy and nutrients, changes to available shelter or cover, increased edge effects that could cause species that do not normally interact to now interact, and increased opportunities for humans to exploit resources or wildlife (i.e., poaching). All of these impacts occur from having a road placed in the middle of a landscape, causing a chain reaction to occur that creates habitat fragmentation to loss of wildlife populations and species. How can this issue be solved so we don’t lose more habitat and wildlife as new roads are created?
Solutions to Habitat Fragmentation
Now that we’ve discussed the issues roads cause to wildlife, from mortality and collisions in my early blog posts to how habitat fragmentation impacts wildlife as well, what are the solutions to help reduce the effects habitat fragmentation has on the land and wildlife? The good news is not all species are necessarily affected by it; species that do not travel very far can only be truly effected if the area they’re in is disturbed, and species that have good dispersal are only affected by the amount of habitat they have access to. However, this does not mean all wildlife are safe from roads causing habitat fragmentation, or habitat fragmentation in general. I was able to find an article discussing the practical considerations of how to address the issue of habitat fragmentation. The main issue of habitat fragmentation is that it is causing wildlife populations and species to decrease in size and amount, causing wildlife to become isolated and not be able to reproduce to keep their populations growing. Barriers such as guardrails or even buildings cause limitations to wildlife movement as well; habitat fragmentation is pushed even further when a road is placed and then there are barriers placed around the road, causing the wildlife to find new corridors to their habitats. One of the main solutions to this issue is utilizing urban green-space to reduce habitat fragmentation and keep intact the connectivity between habitat patches as development continues into the future. In existing urban areas, such as landscapes having a lot of roads or other major infrastructures, green-spaces can be utilized by implementing things such as footpaths, canals and rivers to offer more corridors for wildlife to access instead of using roads to move from habitat to habitat. In urban areas that are becoming newly developed, habitat fragmentation can be counteracted by protecting the already existing patches of habitat that are high in quality and species diversity; this would in turn allow wildlife to still have access to a valuable piece of habitat and allow for the wildlife to not be limited in their movement.
Another great solution to this issue is using habitat network maps; this is a leading development by Forest Research where they develop and apply landscape ecology techniques to combat against fragmentation. Groups of people within this research organization that are concerned with fragmentation have created habitat network maps to evaluate the connectivity of existing wildlife patches and target where to implement new patches when planning urban development. These solutions to the issue of habitat fragmentation will not only help reduce the effects roads have wildlife, but also wildlife increased movement from habitat to habitat and give them more corridors to access as well. The more wildlife movement there is, the more genetic and species diversity will be seen, causing wildlife populations and species to increase rather than decrease. Roads pose serious and adverse effects to wildlife, especially when they’re habitat becomes fragmented an destroyed in the process of implementing the road. If road ecology researchers took more of this into consideration when planning to implement roads in the least destructible way possible, this would in turn benefit the landscape and wildlife in the process.
