Biological Resources (Vegetation & Wildlife)
Biological systems (living organisms) interact and coexist with the non living components and processes (geography, climate, hydrology, chemical cycles, etc.) to create our natural habitat. These complex relationships have developed and evolved over the ages to create the conditions that sustain life for humans. Biological diversity is generally considered to be a key indicator of ecosystem health and stability. As we modify our natural landscapes, ecological design attempts to restore, maintain or enhance natural diversity health and stability.
Ecological succession is that process of change that occurs over time whereby the species composition changes from early colonizers, through a series of transitional communities, to maturity. Succession that begins on a newly exposed area, such as a lava flow or a newly exposed sand dune, is known as primary succession, whereas succession that occurs after a disturbance, such as wildfire, severe storms, clear cutting or bulldozing, on sites previously occupied by a well developed community is known as secondary succession. After a disturbance, whether natural (fire, storm, flood, volcanic eruption) or manmade (deforestation, agriculture, bulldozing, landscaping), the land will be colonized by "pioneer" species. These are typically species that are adapted to the harsh conditions of exposed soils and full sun light. Because of their adaptability and ability to colonize exposed land aggressively, pioneer species are often considered to be pests. Over time, the pioneer species will mature and grow old, modifying the environment, creating shade and improving soil quality, and, in the process, generate conditions favorable to the succession, or colonization, of new species. This process may continue through many successional stages, as one generation creates the conditions favorable to the next, and culminates in the establishment of a “steady-state” or “climax” community. Climax communities represent a species mix that is as stable as is biologically possible for a particular habitat. Examples of climax communities include old growth forests, tall grass prairies and coral reefs.
The human effect on natural ecosystems has often been in the form of a disturbance initiating secondary succession. Most man-altered landscapes are in some state of secondary succession. Those plant and animal species that are characteristic of mature and climax communities are often the ones most threatened, as these communities have largely been replaced with early successional communities. Both horticulture and agriculture species composition is highly weighted towards these pioneer and early succession plant species.
Natural process is based upon change over time and space. Natural landscapes are in a constant process of dynamic transformation. In landscape design and planning we often create plans based on an idea of a static three-dimensional composition, much like a building or classical artwork. We don't often plan for the considerable effects of time on our compositions. In traditional landscapes we resist the natural changes of ecological succession. In striving for a static representation we set ourselves against the natural forces of change. No wonder yard work is never done. The landscape is always in a state of becoming something else, but we want it to maintain it in an arrested state of development. To that end we invest a tremendous amount of energy and generate enormous amounts of waste. In an ultimately futile attempt to maintain iconic representations, we mow, rake, blow, fertilize, pull weeds, and apply pesticides, fungicides and herbicides. We could save ourselves a lot of effort and spare the planet’s valuable resources if we stop all this nonsense and begin to work with nature. Designing and working with nature means embracing change in the landscape. The good news is that ecological landscaping is synonymous with low maintenance. When we embrace and celebrate natural processes, we will no longer need to control the uncontrollable. Liberating ourselves from fixed concepts, we allow ourselves to transform and create a more adaptable society.
Examples:
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Preserve, restore, manage and enhance native plant communities
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Select native plant species
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Select plants to provide food and shelter for wildlife
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Select plants to provide food and material for human use
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Avoid and eliminate invasive plant species
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Select
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Select plants grown locally and with sustainable practices
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Deciduous trees located to South and West of buildings can reduce energy consumption
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Evergreen trees and large shrubs can be used as a wind break or as a sound and visual barrier