Representation

Conservationists need to represent all natural communities in some sort of a conservation network, which is generally a mix of different levels of protection. It is important that the mix of natural communities is one that has existed before a major disturbance rather than the existing mix. But all of these original communities may no longer be present in the quantity and quality necessary, and that is where the potential application of restoration comes in. This is especially true during periods of climate change when species will need to move in response to changing conditions.

One of the first steps in any conservation planning initiative is to obtain or develop a map of historic (sometimes called "potential") natural community types across the entire ecoregion/ priority landscape. A number of coverages may suffice for this purpose, including historic vegetation maps, potential vegetation maps, or maps of plant communities or ecosystems. In the case where land conversion has made this task impossible, maps of environmental domains, which are unique combinations of substrate (soils or geology), elevation, and climate classifications, may be developed. If these environmental domains are carefully developed, they should represent unique environmental classes that correlate with the species living in them.

It is common practice for a target level of representation to be chosen for each natural community type (or environmental domain). This is not always easy, but endeavouring to determine what these levels should be (preferably on an individual habitat-by-habitat basis rather than a blanket prescription) is one of the highest callings of a conservation biologist. It is altogether appropriate to begin with coarse estimates that can be improved over time. Custom representation targets are preferable to blanket prescriptions. Once an appropriate level of representation of each historic natural community is decided (20 percent, 30 percent, 50 percent, etc.), it may be discovered that less intact habitat of a particular type(s) remains than the target representation amount. This is a sign that some restoration is in order. Madagascar and the dry forests of New Caledonia are prime examples—forest conversion has proceeded so far in these ecoregions that forest restoration is required to meet the most basic habitat representation goals.

It should also be noted that each natural community is itself made up of seral stages, and the appropriate mix of seral stages, or more likely the allowable ranges of seral stages, corresponding to a natural range of variation, must be specified. The ability of a natural community type to support a natural range of seral stages must be protected, or if necessary enhanced, and this may also require some forest restoration activities. An example is the relative lack of primary, or old-growth forest, in many temperate forest ecoregions compared to historic levels. Efforts to increase the proportion of late seral stages are an appropriate application of forest restoration in this case.

Many ecoregional programmes, especially those in developed or densely populated countries, have found that the amount of lowland and riparian communities are in short supply— they have already been converted for human uses. Clearly in such situations, restoration will necessarily be an important component of the overall conservation strategy if representation targets are to be met.

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