The overarching solution presented within this section will be the construction of green spaces connected by wildlife corridors, both through implementation in existing cities and through incorporation in currently developing urban areas. Generally, a network of effective corridors and large patch areas are the most important methods in maintaining high levels of urban biodiversity, compared to other preservation strategies.[1] Critical factors for the success of both wildlife corridors and green spaces will be laid out in the following pages, and the practicality of such solutions will be demonstrated through case studies.
Ultimately, green spaces and wildlife corridors will be addressed in the contrasting contexts of present cities and currently developing areas. The former approach will focus on improving current cities, specifically Boston, through both urban planning strategies and policy proposals. The latter will focus on creating spaces that would allow for a future city that coexists with the surrounding ecosystem. Both of these perspectives will maintain a focus on wildlife corridors and green spaces.
Wildlife Corridors
The most viable compromise to perfect nature preservation that has been explored tangibly thus far has been wildlife corridors, which have demonstrated substantial improvements in biodiversity.[2] These seek to integrate surrounding wildlife with urban areas and allow them to cohabitate with the cities that currently threaten them. A wildlife corridor is a small-scale corridor of native flora in an urban setting that allows animals to move on a daily basis and interact with other previously-fragmented populations.
The proposed solution will focus on implementing optimal wildlife corridors for the native species in the Boston area and future cities. Initially, an evaluation of which factors form the greatest barriers to the movement of wildlife within the city should be conducted. Major highways, roads, and infrastructure, for example, seriously impede the free and natural flow of wildlife. It is also important to identify specific areas and species that are affected by disproportionally high levels of fragmentation. A successful wildlife corridor both allows the physical movement of animals, and critically, enhances the gene flow between populations. This results in greater genetic diversity, and a network of stronger, and more resilient, populations of organisms.
Steps also must be taken to limit the impacts of nearby human activity. This is because both noise and light pollution are detrimental to the efficacy of the corridor, and can be major stressors to corridor-dwelling species.[3] Natural wildlife corridors can be maintained by implementing regulations that allow for the uninterrupted passage of animals.
Green Spaces and Urban Natural Parks
When considering green spaces and natural parks in urban spaces, special attention must be given to their placement and size. It has been found that even urbanized species of birds require 10-35 hectares of continuous green space.[4] This limits placement of green spaces in densely built urban areas. Other important factors to consider in the construction of green spaces include the size, connectivity, distribution, and method of connection of green spaces, specifically with the recognition that “stepping stone” pathways are also viable forms of wildlife corridors between natural parks.[5] To effectively connect fragmented populations, links between smaller spaces must be created to prevent ecological traps and population sinks. Indeed, according to the Population Reference Bureau, “much of what determines the extent of the environmental impacts is how the urban populations behave—their consumption and living patterns—not just how large they are”.[6] Other considerations include the amount of endemic vegetation in green spaces, as well as human activity within these areas. A key way to ensure the created space will promote biodiversity is to utilize a variety of native vegetation.[7] Finally, it is important to evaluate the viability of conservation of natural habitats, in comparison to the construction of new and artificial green spaces.
It must be taken into account that natural park construction requires an evaluation of social and architectural perspectives alongside the scientific issues associated with biodiversity.[8] Public opinions can heavily impact the placement of these spaces. Care must be taken to plan urban parks that will encourage engagement and education while simultaneously avoiding connectivity issues.[9] Natural parks can promote public involvement with wildlife in the city, resulting in greater environmental education and the promotion of sustainability initiatives.
With these criteria in mind, the proposal will include a natural park that increases the biodiversity of the area by providing a space for species populations to thrive.
Criteria for Success
The metrics for success will be a statistically significant (with a significance level of 5%) increase in taxonomic and genetic diversity within the city (as defined on the What Is Biodiversity? page), as well as in the rate of species travel throughout urban spaces. To measure taxonomic and genetic diversity, a pre-implementation baseline assessment of the numbers of endemic species outside urban limits as well as a measure of the genetic variability within the populations of these species will be utilized. In addition, the measurement of the rate of species traveling within the urban area and the taxonomic and genetic diversity of those species will be considered. The comparison of the biodiversity of species residing in the center of urban areas with the biodiversity of those living on the outskirts of cities will also serve as a benchmark to compare the greenification progress of a city. Post-implementation, these measurements should be taken again every ten years using a distribution mapping tool. Success is defined as a statistically significant increase in genetic and taxonomic diversity both inside the urban area and on its periphery, as well as an increase in the total number of species inside city parks and corridors per square unit area.