Question

While human impacts on the ecology of our planet have been huge and often negative there are clear examples of where we have mitigated to a significant extent these negative impacts once we realized their importance for the health of life on earth. Give two examples.

Answer 1

Environmental mitigation is the process of addressing impacts to the environment caused by human action — notably those resulting of highway, energy, water, and other infrastructure projects. The following are a few examples of the problems posed to wildlife by human intervention and the mitigation strategies adopted:

1. Roads and traffic impact wildlife in a variety of ways. In some animal populations, they enhance mortality, limit mobility, fragment populations, and decrease habitat amount and quality, resulting in a limitation on food, shelter, and space availability, all fundamental to species' survival. Some of the mitigation strategies adopted to mitigate the ill effects of road constructions to wildlife are:

· Crossing structures: species benefit from crossing structures across the roads. They help to restore landscape permeability. The crossing structures include small, average sized or large underpasses (metal or concrete pipe culverts or small boxes 1.5m span or less, through which wildlife can travel under the road); extensive bridges built to span valleys, roads, and streams and dry ledges [In Portugal, Colorado and Montana (USA),the installation of ledges in culverts facilitated movement of small and meso-sized mammals].

· Fencing: Fencing and barrier walls used in conjunction with crossing structures is an effective means to prevent access to roads thus reducing road mortality. Fence type can vary and may be concrete, wood, plastic, polythene mesh, metal mesh for smaller animals to a minimum of 2.5m for large mammals. An example of successful use of fencing is the temporary drift fences installed over a 0.7km section of the highway at Lake Jackson (Florida, USA). This decreased road surface crossing of for turtles by 98% and for semi aquatic individuals by about 25%.

2. Construction of infrastructure projects in the natural habitats of organism poses a great threat to the survival of several species. Landscape level mitigation is necessary to avoid the impacts of such developmental projects. An important example of such a mitigation strategy is the attempts to protect the habitat of the greater sage grouse, a bird that is threatened and needs large expanses of land to provide habitat for the various stages of its lifecycle, in North America. A large, multi-agency group is working to inventory – at a landscape scale – the bird’s remaining habitat. The group’s goal is to identify important habitat strongholds for the species, some of which may be insufficiently protected and vulnerable to being lost. The adoption of more stringent regulations regarding greater sage grouse and plans to mitigate at the landscape scale is highly relevant and particularly useful in siting new energy facilities.