Calculating protected area coverage

When calculating protected area coverage at any scale there are four questions that will have a major influence in the final results:

1) What is a protected area?

2) What protected areas data is used?

3) Which base map layer is used?

4) Which method should I follow?

The decisions made when responding to these questions will have an important influence in the final results. Therefore differences between the www.protectedplanet.net national statistics and any other national statistics can be expected.

UNEP-WCMC acknowledges these differences and works closely with countries and territories when the calculation in www.protectedplanet.net and national official statistics differ. The aim is that the data in the WDPA accurately reflects the protected area network of each country and territory

1)What is a protected area?

UNEP-WCMC only use protected areas that meet the IUCN and CBD definitions of protected areas when calculating protected area coverage. For more information see this: http://www.biodiversitya-z.org/content/protected-area

2)What protected areas data is used?

UNEP-WCMC only uses points and polygons submitted to the World Database on Protected Areas. The majority of these sites are available for download at www.protectedplanet.net. However, due to restrictions requested by the data providers, a small number of sites are not made publicly available, but are used in our analyses.

UNEP-WCMC decides not to include all sites in the database for protected area coverage analyses. Proposed protected areas are excluded as are sites submitted as points with no reported area (more information is available in Section 4). Currently UNESCO Man and Biosphere Reserves (MAB) are excluded, on the basis that that the MAB sites currently in the WDPA include buffer and transition zones that in many cases are not protected areas. MAB Core areas are usually protected areas designated at a national level and are therefore generally accounted for in our calculation. UNEP-WCMC is working with the MAB Secretariat to have an accurate set of boundaries for the core areas to ensure the contribution of these sites is accurately reflected. .

3)Which base map layer is used?

UNEP-WCMC use a dataset combining Exclusive Economic Zones (EEZ; VLIZ 2014) and terrestrial country boundaries (World Vector Shoreline, 3rd edition, National Geospatial-Intelligence Agency). A simplified version of this layer has been published at Nature Scientific Data journal ( Brooks et al. 2016) and is available here: http://datadryad.org/resource/doi:10.5061/dryad.6gb90.2

Every country or territory has its own detailed base layer which is used at a national level for calculations of area and other statistical requirements. By using a global data set to calculate national values there is an acknowledged potential for the results to differ slightly from those used at the national level. This will have an influence on the final protected area coverage for that country or territory.

The designations employed and the presentation of materials and maps in www.protectedplanet.net do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.

4)Method used to calculate national protected area coverage

This is a step by step guide on the method used to calculate national protected areas coverage in www.protectedplanet.net. National statistics split by regions are available here.

1.Start with the latest WDPA monthly release. For the data that is currently on the country profile pages the latest WDPA monthly release is used.

2.Only sites with Status = designated, inscribed, and established are included.

3.Only points with a Reported Area are included.

4.Sites with Status = Proposed, Not Reported; points with no reported area, and UNESCO Man and Biosphere Reserves (see reasons above in Section 2) are excluded.

5.A buffer is created around protected areas reported as points. The area of the buffer is = Reported Area. There are important caveats associated with this method some of which are explored by Visconti et al. 2013. Buffering points can underestimate or overestimate protected area coverage as the circles created around points might cover areas where protected areas do not exist (overestimation) or overlap with areas where other protected areas already exist (underestimation). It can also give inaccurate values for sites that are partly terrestrial and marine as the absence of boundaries make it difficult to predict which portion of a protected area is in the land or the sea.

6.All buffered point and polygons are combined into one single feature dataset.

7.The "Dissolve" tool in Arc GIS is used to eliminate overlaps between designations and avoid double counting. The field ISO3 is kept to represent each country or territory. Transboundary sites will be allocated areas to different countries using our base map (see Section 3).

8.The dissolved output is intersected with the coast line (see Section 3 above). The intersected output has its area recalculated in the Mollweide projection and is is used to calculate the protected area coverage of every country and territory. Marine and coastal area are those outlined in the Economic Exclusion Zones dataset (see section 3 above). Beyond 200 nautical miles is considered as Areas Beyond National Jurisdiction (ABNJ).

9.The terrestrial protected area coverage is calculated for each country or territory by dividing the total area of terrestrial protected areas by total terrestrial area of that country.

10.The marine and coastal protected area coverage is calculated for each country or territory by dividing the total marine and coastal area of protected areas by total marine and coastal area of that country.

To complete a successful analyses it is fundamental to check and repair geometry at least after steps 7 and 8 and run topology tests to identify any duplicates or geometry issues. This is a simplified methodology, if you have any further questions please contact us at [email protected]

5)Method used to calculate global protected area coverage

This is a step by step guide on the method used to calculate global protected areas coverage in www.protectedplanet.net.

1.Start with the latest WDPA monthly release.

2.Only sites with Status = designated, inscribed, and established are included.

3.Only points with a Reported Area are included.

4.Sites with Status = Proposed, Not Reported; points with no reported area, and UNESCO Man and Biosphere Reserves (see reasons above in Section 2) are excluded.

5.A buffer is created around protected areas reported as points. The area of the buffer is = Reported Area. There are important caveats associated with this method some of which are explored by Visconti et al. 2013. Buffering points can underestimate or overestimate protected area coverage as the circles created around points might cover areas where protected areas do not exist (overestimation) or overlap with areas where other protected areas already exist (underestimation). It can also give inaccurate values for sites that are partly terrestrial and marine as the absence of boundaries make it difficult to predict which portion of a protected area is in the land or the sea.

6.All buffered point and polygons are combined into one single feature dataset.

7.The "Dissolve" tool in Arc GIS is used to eliminate overlaps between designations and countries and avoid double counting.

8.The dissolved output is intersected with the base layer (see Section 3 above). The intersected output has its area recalculated in the Mollweide projection and is is used to calculate global protected area coverage. Marine and coastal area are those outlined in the Economic Exclusion Zones dataset (see Section 3 above). Beyond 200 nautical miles is considered as Areas Beyond National Jurisdiction (ABNJ).

9.The terrestrial protected area coverage is calculated by dividing the total area of terrestrial protected areas by total global terrestrial area excluding Antarctica.

10.The marine and coastal protected area coverage is calculated by dividing the total marine and coastal area of protected areas by total marine and coastal area of that country.

To complete a successful analyses it is fundamental to check and repair geometry at least after steps 7 and 8 and run topology tests to identify any duplicates or geometry issues. This is a simplified methodology, if you have any further questions please contact us at [email protected]