ECOTONES + DESIGNING FOR BIODIVERSITY
By Brad Priest, Landscape Designer
Whenever possible, we attempt to promote the health of the environment through our landscape architectural projects. One way that we can accomplish this goal is by encouraging biodiversity – i.e. creating conditions favorable to support a variety of plant and animal species. Biodiversity is important from an ecological standpoint because the more biologically varied an ecosystem is, the more stable and self-sustaining it becomes.
Through design there are many ways we can promote biodiversity in the landscape. One of the most important ways is to focus on ecotones, or the transition zones between differing ecosystem types. Ecotones are hotbeds of biodiversity, typically inhabited by a wide range of species due to the variety of environmental conditions, and abundance of food sources and shelter. Some common examples of ecotones are the edge where a forest meets a field, where water meets land, or even where a lawn meets a planting bed. In any case, these transition zones are important areas to consider when attempting to encourage biodiversity through landscape design. A primary way to take full advantage of the benefit of ecotones is to focus on the design of the shape and length of these transition zones.
Above: Ecotone interface along the edge between forest and field.
The shape of an ecotone can be as simple as a straight, stark line. However, in general the more convoluted the edge is, the more linear feet of real estate are available for those species that like to hang out in the ecotone, and thus the more species diversity that will likely exist (see Figure 1 below).
This concept can be translated into landscape design via intentional shaping of the edges of planting areas. Sinuous edges and gradual transitions provide maximum area for ecotone habitat, and they often fit in well with informal, natural-looking landscapes. In contrast, contemporary or formal landscapes that are often filled with straight lines and angles can necessitate sharp and more distinct ecotone shaping. Inclusions of the different plant communities and jagged planting edges serve to maximize the space for ecotones in these instances.
Figure 1: The diagrams above depict various configurations of ecotones – some are sharp and distinct, while others can be gradual and subtle.
While there are myriad ways that landscape designers can plan for biodiversity, the implementation of extensive ecotone habitat can be one of the most ecologically valuable at almost any scale. Being able to seamlessly integrate ecotones into the overall design such that a space can be made enjoyable by both man and nature is something we strive to accomplish in projects of all shapes, sizes and types.