Sustainable Communities Workshop Eight Principles Relating to Ecological Sustainability Alan Haney

1. Communities are the fundamental unit of ecological sustainability 1. Communities are the fundamental unit of ecological sustainability. Size matters.   To be sustainable, communities can be neither too big nor too small. The "tools" used by nature to maintain communities ensures that they do not get too big. Human activities tend to break large communities into smaller ones. Fragmentation of larger communities into smaller ones, and discontinuities/barriers within landscapes are real threats to ecological sustainability.

The principle "tool" nature uses to create and maintain communities is symbiosis. The most important components are: a. Competition, both intra- and inter-specific. b. Mutualisms (there are thousands, most of which we don't know about) c. Disease and parasitism d. Predation e. Hormonal regulation/territorial tendencies By and large, these symbiotic relationships all limit growth, and keep growth adjusted to the available resource base.

Duplication of structure and functions of essential components (listed above). When one population is damaged or loss, the overlap with other populations permits continuance of vital functions. We know this as diversity and redundancy. Anything damaging this diversity and redundancy probably reduces sustainability.

With scarcely any exception, resources used by sustainable ecosystems are either nearly 100% recycled, or in the case of energy, renewable, primarily solar. However, not all resources are recycled internally. Many, such as carbon, oxygen, nitrogen, and hydrogen are recycled externally in the global ecosystem to a great extent.

The infrastructure of an ecological community is completely organic ; all components are derived from nature and recycled by natural processes. This is achieved by the functions of primary producers (energy gatherers), consumers, and decomposers. The population of each functional group must be adjusted to fit compatibly with the overall community, and this is accomplished by the tools mentioned in 2, above.

The total economy of a sustainable ecosystem is limited by the available resources within the system. Natural communities live within their means. Natural ecosystems do not borrow against the future to shore up short-falls or to stimulate the economy. When resources become limiting, the community downsizes.

Not only spatial, but also temporal scale is important when evaluating sustainability. Temporal scale applies because all sustainable systems must be viewed as dynamic steady-state systems. The inputs and outputs will ebb and flow. Evaluated over too little time can easily lead to incorrect conclusions about sustainability. The longer the better when it comes to evaluating sustainability.

The currency of ecological sustainability is environmental quality. Leopold summed it up beautifully: "A thing is right when it tends to preserve the integrity, stability and beauty of the biotic community. It is wrong when it tends otherwise."

The currency of ecological sustainability is environmental quality. Leopold summed it up beautifully: "A thing is right when it tends to preserve the integrity, stability and beauty of the biotic community. It is wrong when it tends otherwise." Can this same principle be applied to human economies?