This provisional Biogeographic Analysis Package provides an analysis of protection status for ecological systems within Omernik Level III Ecoregions. The ecological system classification defines groups of plant communities that tend to co-occur within landscapes with similar ecological processes, substrates, and/or environmental gradients and is the primary map class used in the Gap Analysis Program (GAP) land cover layer (based on 2001 satellite imagery). This package can be used to identify the ecoregions where ecological systems have the greatest representation in GAP Status 1 and 2 lands (lands managed for the protection of biodiversity) and the ecoregions where ecological systems are the least protected.
One important use of the data in this Biogeographic Analysis Package is to evaluate what proportion of the ecological systems in an ecoregion are managed for long-term conservation. These data can be expressed as “threshold” levels of ecological system protection. These thresholds provide a convenient reporting framework. The following thresholds of ecological systems protection are used in this Biogeographic Analysis Package. For definitions of GAP Status codes see: https://www.sciencebase.gov/vocab/vocabulary/56db17ede4b0c798f3c8b712.
- Threshold 1: Less than 1% of ecological system is on GAP Status 1 and 2 lands (least protected).
- Threshold 2: From 1% to less than 10% is on GAP Status 1 and 2 lands.
- Threshold 3: Between 10% and less than 17%* is on GAP Status 1 and 2 lands.
- Threshold 4: Between 17% and 50% is on GAP Status 1 and 2 lands or on GAP Status 1, 2, and 3 lands.
- Threshold 5: More than 50% of ecological system is on GAP Status 1, 2, and 3 lands (most protected).
* 17% represents the 2020 target threshold for protection of terrestrial ecosystems agreed upon by Parties to the Conservation on Biological Diversity during the Aichi Convention. < https://www.cbd.int/sp/targets/>
Data Use Constraints
These provisional data were compiled with regard to the following standards and appropriate uses. Please be aware of the limitations of the data.
- These data are meant to be used at a scale of 1:100,000 or smaller (such as 1:250,000 or 1:500,000) for the purpose of assessing the conservation status of animals and vegetation types over large geographic regions.
- All information is created with a specific end use or uses in mind. For the Gap Analysis Program, minimum standards were set including: scale or resolution (1:100,000 or 100 hectare minimum mapping unit), accuracy (80% accurate at 95% confidence), and format (ARC/INFO coverage tiled to the 30' x 60' USGS quadrangle).
- Scale: The data were produced with an intended application at the ecoregion level, that is, geographic areas from several hundred thousand to millions of hectares in size. The data provide a coarse-filter approach to analysis, meaning that not every occurrence of every plant community or animal species habitat is mapped, only larger, more generalized distributions.
- The data are also based on the USGS 1:100,000 scale of mapping in both detail and precision. When determining whether to apply GAP data to a particular use, there are two primary questions: Do you want to use the data as a map for the particular geographic area, or do you wish to use the data to provide context for a particular area? The example below illustrates two appropriate uses of the data: as a coarse map for a large area such as a county and to provide context for finer-level maps.
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You could use GAP land cover to determine the approximate amount of oak woodland occurring in a county, or you could map oak woodland with aerial photography to determine the exact amount. You then could use GAP data to determine the approximate percentage of all oak woodland in the region or state that occurs in the county, and thus gain a sense of how important the county's distribution is to maintaining that plant community.
- Appropriate uses: statewide biodiversity planning; regional habitat conservation planning; large-area resource management planning; coarse-filter evaluation of potential impacts/benefits of major projects on biodiversity (e.g., utility or transportation corridors, wilderness proposals, recreation proposals); determining relative amounts of management responsibility for specific biological resources among land stewards to facilitate cooperative management and planning; basic research on regional distributions of plants and animals and to help target both specific species and geographic areas for needed research; environmental impact assessment for large projects or military activities; and estimation of potential economic impacts from loss of biological resource-based activities.
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Inappropriate uses: There is a "fuzzy line" that is eventually crossed when the differences in resolution of the data, size of geographic area being analyzed, and precision of the answer required for the question are no longer compatible. Examples of inappropriate uses include: using the data to map small areas (less than thousands of hectares), typically requiring mapping resolution at 1:24,000 scale and using aerial photographs or ground surveys; combining GAP data with other data finer than 1:100,000 scale to produce new hybrid maps or answer queries; generating specific areal measurements from the data finer than the nearest thousand hectares (minimum mapping unit size and accuracy affect this precision); establishing exact boundaries for regulation or acquisition; establishing definite occurrence or non-occurrence of any feature for an exact geographic area (for land cover, the percent accuracy will provide a measure of probability); determining abundance, health, or condition of any feature; and establishing a measure of accuracy of any other data by comparison with GAP data.
