From Halpern et al. 2012 supplemental info:
The ‘Lasting Special Places’ sub-goal focuses instead on those geographic locations that hold particular value for aesthetic, spiritual, cultural, recreational or existence reasons57. This sub-goal is particularly hard to quantify. Ideally one would survey every community around the world to determine the top list of special places, and then assess how those locations are faring relative to a desired state (e.g., protected or well managed). The reality is that such lists do not exist. Instead, we assume areas that are protected represent these special places (i.e. the effort to protect them suggests they are important places).
Clearly this is an imperfect assumption but in many cases it will be true. Using lists of protected areas as the catalogue of special places then creates the problem of determining a reference condition. We do not know how many special places have yet to be protected, and so we end up having all identified special places also being protected. To solve this problem we make two important assumptions. First, we assume that all countries have roughly the same percentage of their coastal waters and coastline that qualify as lasting special places. In other words, they all have the same reference target (as a percentage of the total area). Second, we assume that the target reference level is 30% of area protected.
The model for this goal considers the inland coastal zone (up to 1 km inland) independently from, and equally weighted with, the offshore coastal zone (up to 3 nm offshore). The status for this goal is calculated as:
\[X_{LSP} = \frac{\left(\frac{Area_{P}}{Area_{P_{ref}}} + \frac{Area_{MPA}}{Area_{MPA_{ref}}}\right)}{2}\]
where:
No longer use ArcPy for rasterization of WDPA-MPA database. ArcPy works great for our purposes, but is neither open-source nor cross-platform. Using fasterize
in R to rasterize the shapefiles.
Reference: IUCN and UNEP-WCMC (2018), The World Database on Protected Areas (WDPA) [On-line], June 2018. Cambridge, UK: UNEP-WCMC. Available at: www.protectedplanet.net.
Downloaded: July 2, 2018
Description: Shapefile of World Database on Protected Areas
Time range: 1819 - 2018; some protected areas do not have an associated “status year” and are reported as year 0.
Format: Shapefile
File location: Mazu:git-annex/globalprep/_raw_data/wdpa_mpa/d2018/WDPA_June2018-shapefile/
The WDPA-MPA dataset comes as a shapefile or geodatabase in WGS84 coordinate reference system.
Once the polygons have been prepped, we rasterize the results to 500 m resolution.
This process is all done in the script: 1_prep_wdpa_rast.Rmd
. After that is complete, move on to computing zonal statistics.
Comparing the global WDPA raster to the 3 nautical miles offshore and 1 km inland rasters, we can tally the protected area within each region and compare to the total area within each region. Note each cell is 500 m x 500 m, so area is .25 km2, but since we are simply calculating a ratio, this cancels out.
Once the WDPA raster is cross-tabulated against the OHI region rasters (both 3 nm offshore and 1 km inland) we have the number of protected cells, identified by year of protection, within each region. NA values are unprotected cells.
Grouping by rgn_id, the total number of cells per region is determined by summing cell counts across ALL years, including cells with year == NA (unprotected cells). We can then determine the protected area for each year by looking at the cumulative sum of cells up to any given year.
Since the cells are 500 m on a side, we can easily calculate area by multiplying cell count * 0.25 km2 per cell.
Finally we can calculate the status of a region for any given year by finding the ratio of protected:total and normalizing by the goal’s target of 30% protected area.
From the protected area files, write out the individual layers ready for the Toolbox[TM].
Some goals require calculation of resilience nearshore (3nm) or entire EEZ.
There was no gapfilling for these data. Created gapfill files with values of 0.
Plot scores for 2018 vs 2017 assessment years