Biogeography Helps Restore Ecosystems
Understanding Plants and Climate is Key to Ecological Restoration
Humans have had an enormous impact on global ecosystems. Those who practice ecological restoration work to restore the ecological processes, plants, animals, and interactions between these plants and animals. For example, a restoration ecologist might work to remove an urban stream from a culvert, place plants around the stream, and encourage local animals to return to that stream. A good understanding of local climate and biogeography is crucial to successful restoration.
Geography Leads to Different Ecological Regions
The world has many different ecoregions, or biomes. Different parts of the earth have different rainfall patterns, temperature, and light levels throughout the year. Some of the differences between biomes are due to a particular area's location on the earth. Climate, light, and temperature combine to yield distinctly different geographic regions with plant and animal species that are well-suited to the region. For example, the equator receives the most direct sunlight for the majority of the year, leading to the growth of tropical rainforests. Regions on the lee or dry side of a mountain tend to have plants and animals that are suited to dry conditions. Biogeography is the study of the large-scale and small-scale geographic differences that produce areas with distinctive vegetation and animal life.
Understanding Biogeography is Key to Ecological Restoration
One of the first things that those who work to restore ecosystems need to do is to study the indigenous plants and animals of the area that they want to restore. What plants grow in nearby areas that have experienced fewer human impacts? For example, in a temperate rainforest the restoration practitioner might discover that Douglas-fir, Western Redcedar, and Western Hemlock are the primary tree species. Huckleberry bushes, salmonberry and salal often grow undernearth the canopy of trees. While a general understanding of the large-scale ecoregion is important, next the practitioner must also look at the smaller-scale processes at work on the specific restoration site.
Understanding Small-Scale Biogeography: Succession and Disturbance in the Ecosystem
Good restoration also depends on a solid understanding of the restoration site. For example, a streamside or riparian environment will have very different plants than a mature forest environment. This is due to the small-scale geographic differences in the two areas. A stream often floods its banks. Plants next to a stream must be adapted to frequent disturbances and they must be able to grow quickly when they are not disturbed. When a lot of trees have been pushed down by floods, this also leaves open spaces, so plants that grow next to streams often like the light. They also like sandier soil, since the stream deposits sand on its banks when it floods. All of these small-scale geographic factors are important when choosing species to plant.
Succession is the term used to describe the changes in an ecosystem over time. Early successional species might be a good choice for an area that experiences a lot of disturbance. These species often prepare the soil chemistry and make it stable for other, slower-growing plants to take over. In an area that will be restored and will not be disturbed very often, a mixture of fast and slower-growing plants woul be appropriate.
A solid understanding of geography is key to understanding the large and small-scale processes that impact the success of ecological restoration. An understanding of the indigenous plants of a specific bioregion coupled with an understanding of the small-scale geography of the restoration site will lead to better success in restoring a place.
Sources:
National Geographic Society and World Wildlife Fund. 2001. Map of the Terrestrial Ecosystems of the World.
Ecological Restoration
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