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Protected Areas Data

PAD-US is America’s official national inventory of U.S. terrestrial and marine  protected areas (List of National Geospatial Data Assets) that are dedicated to the preservation of biological diversity and to other natural, recreation and cultural uses, managed for these purposes through legal or other effective means. Lands in PAD-US are mainly open space/resource lands owned in fee by agencies and non-profits. Conservation easements suitable for distribution in the public domain are also included. The current data set includes the “gap ranks” of these lands, indicating how they are being managed for conservation purposes. PAD-US includes all federal and most state conservation lands, and many areas at regional and local scales, with plans underway to expand these holdings in the database.

Why are Protected Areas data important?

Detailed information about the conservation status of our country’s protected areas is crucial to improving our understanding of how well we are protecting the animals and plants that inhabit those areas. Natural resources decision-makers, planners, researchers, private interests and others also use this information in many other ways from locating and siting public resources such as recreation areas and energy facilities, to planning for and mitigating the impacts of climate change.


How GAP Protected Areas data can be used

Information about the conservation status of common species – the purpose of protected area analyses — is important for decision makers, planners, researchers, private interests and others:

  • Biodiversity: Protected areas (parks, preserves, etc.) have often been set aside without full understanding of their value to species conservation. As a result, many protected areas have little significance in terms of biodiversity, while many biodiversity-rich areas lack protection. Information provided by the PAD-US Program can help land conservation decision makers better match biodiversity goals to land protection programs and activities.
  • Habitat Loss: Human population in the U.S. is predicted to grow by 25% in the next 50 years. This population increase, coupled with our land consumption patterns, means that there will be significant decreases in habitat for other species. Efforts to target the most effective lands for biodiversity conservation can offset some or many of the effects of habitat loss.
  • Climate: Accelerating climate change is elevating the importance of effectively targeted species protection efforts. For many species, warming climates could push them to the brink of extinction unless habitat migration corridors can be set aside. Protected Areas analysis is critical to understanding where to focus such corridor planning.
  • Energy Siting: Renewable energy projects are growing, as solar and wind farms are planned and built across the U.S., often aided by governmental incentives. Protected area analysis can inform this planning and siting work, helping energy projects to find the best balance between habitat conservation and much-needed energy production.
  • Management: Agencies and non-profits that manage protected areas often lack good information about the full range of species that might be present or could be encouraged on their lands. The Protected Area Analysis Program can provide tools to improve land management practices that support continued biodiversity.

Description of PAD-US Data

How to Cite Data:

U.S. Geological Survey, Gap Analysis Program (GAP). May 2016. Protected Areas Database of the United States (PAD-US), version 1.4 Combined Feature Class.

Main Purpose

The goals of the USGS Gap Analysis Program (GAP) are to provide landscape (e.g. state, watershed, regional and national) assessments of the conservation status of native vertebrate species and natural land cover types and to facilitate the application of this information to land management activities. The PAD-US geodatabase is required to organize and assess the status (i.e. land ownership and GAP Status Code) of protected areas for biodiversity protection. GAP has committed to develop and maintain PAD-US while implementing recommendations from the PAD-US Design Project (see A Map for the Future report) to the extent resources allow. The PAD-US geodatabase is built to support landscape analyses by describing all protected areas to illustrate patterns and possible relationships with other factors (e.g. urban areas, migration corridors) across the landscape. Characteristics of protected areas such as land owner, name, location, size and a measure of biodiversity management intent are compiled and standardized.

Our current objective is to refine the PAD-US standard to facilitate more efficient sharing of authoritative protected areas data between agencies and organizations that ultimately results in a comprehensive and accurate inventory of protected areas for the United States to meet a variety of needs (e.g. conservation, recreation or energy planning, ecological or watershed assessments). In cooperation with UNEP-World Conservation Monitoring Centre (WCMC) and the Commission for Environmental Cooperation (CEC), GAP ensures PAD-US also supports continental and global decision making by maintaining World Database for Protected Areas (WDPA) Site Codes and International Union for the Conservation of Nature (IUCN) Categories for linkage to the North American Terrestrial Protected Areas Database and WDPA.

PAD-US data features

PAD-US is available as a zipped national, regional, state, or Landscape Conservation Cooperative (LCC) geodatabase or shapefile. The following are included in PAD-US:

  • Geographic boundaries of public land ownership (primarily federal and state, local government data is incorporated with increasing frequency) and voluntarily provided private conservation lands (e.g., Nature Conservancy Preserves or land trust easements) from authoritative data sources.
  • Standardized and original land owner, land manager, management designation and parcel name descriptions, areas and the source of geographic information of each mapped land unit.
  • GAP Status Code – conservation measure of each parcel based on protection level categories that provide a measure of management intent for the long-term protection of biodiversity.
  • IUCN category – a globally inter operable conservation measure required for a protected area’s inclusion into UNEP-World Conservation Monitoring Centre’s (WCMC) World Database for Protected Areas (WDPA).
  • Reference information – aggregator source and original GIS source and dates.
  • See “Readme.txt” and metadata files included in download for more information.

How these data were aggregated

Boundaries, and their descriptors, available in spatial databases (i.e. shapefiles or geodatabase feature classes) from land management agencies are the desired and primary data sources in PAD-US. If these authoritative sources are unavailable, or the agency recommends another source, data may be incorporated by other aggregators such as non-governmental organizations. Data Sources are tracked for each record in the PAD-US geodatabase (see below).

The “Aggregator Source” field in the PAD-US geodatabase documents the organization, aggregated database name, year and file type credited with data aggregation (e.g. TNC_SecuredAreas2008.shp or BLM_sma_20090914.gdb). A data aggregator submits data in the PAD-US schema according to standards and/or aggregates state, regional or national datasets with required information for translation into PAD-US by GAP.

The “GIS Source” field in the PAD-US geodatabase identifies the original source of GIS spatial and attribute information the aggregator obtained for each record (e.g. WYG&F_whmas08.shp). This field and/or the Aggregator Source field should reference authoritative data provided by the land manager whenever possible.

The “GIS Source Date” describes the date (yyyy/mm/dd) GIS data was obtained by the data source for aggregation. This date represents the best available data the GIS source has at the time.

Data Limitations

PAD-US is an aggregated dataset that incorporates data as provided by land owners, administrators or best available sources (e.g. NGOs). As GAP does not alter source boundaries, inconsistencies in data quality or scale are present. Given these differences, GAP recommends PAD-US for use in landscape analyses of 1: 100,000 or greater. While parcel level data is increasingly available, protected area boundaries should be considered representative of management rather than legal boundaries for regulation or acquisition.

GAP also relies on source data for protected area descriptors (e.g. name, owner, designation date) and translates multiple data formats into the PAD-US schema. When information is unavailable or contains errors the overall utility of PAD-US suffers. GAP addresses comments that improve the data but, ultimately, depends on the integration of suggested edits in source data to avoid the repetition of errors in future updates.

PAD-US is updated annually however, given current resources, this does not include a complete update of all land types across the nation. An update summary is available for each version, while boundary and conservation measure update dates are documented for each record in the ‘GIS Source Date’ and ‘GAP Code Source Date’ fields in the PAD-US geodatabase, respectively.

Despite these limitations, we believe PAD-US is a valuable and powerful tool for assessing landscape level conservation questions and planning. It is the responsibility of data users to evaluate the suitability of PAD-US for their intended purpose.


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