Protected Area Connectedness Index
The Protected Area Connectedness Index represents connectivity among terrestrial protected areas. It integrates information from remotely-sensed forest change and land cover change datasets with a global protected area database.
By 2020, at least 17 per cent of terrestrial and inland water, and 10 per cent of coastal and marine areas, especially areas of particular importance for biodiversity and ecosystem services, are conserved through effectively and equitably managed, ecologically representative and well connected systems of protected areas and other effective area-based conservation measures, and integrated into the wider landscapes and seascapes.
This indicator ranges from 0-1, with values closer to 1 indicating land that is well-connected to other protected areas and areas of intact native vegetation, while values closer to 0 indicate land in less connected protected areas. A decrease in the Protected Area Connectedness Index reflects disconnection between protected areas, which can be symptomatic of loss of protected areas, loss of intact vegetation, or fragmentation among protected areas/intact vegetation.
This indicator is currently available globally at the basin, country, region and FAO ecological zone scales.
This indicator is available for the years 2000, 2005, 2010, and 2012.
The average rate of annual change in the Protected Area Connectedness Index score is available for the period 2000-2012.
The Protected Area Connectedness Index value of each protected cell in relation to other cells that are protected or contain primary vegetation in the surrounding non-protected landscape is scored using the cost-benefit analysis (CBA) technique described by Drielsma et al. (2007). Each of the protected cells of interest is first assigned a “benefit” value, representing the proportion of that cell included in protected areas or covered by primary vegetation (outside reserves) (Santini et al. 2015; UNEP-WCMC 2016; WDPA). Each cell in the surrounding landscape is also assigned a “cost” value, indicating permeability to dispersal through that cell, scaled from 0.1 for cells with no protection or primary vegetation through to 1.0 for cells fully protected or covered by primary vegetation. The primary vegetation is based on statistical downscaling of remotely-sensed MODIS land cover data (Friedl et al. 2010; Hoskins et al. 2016), abiotic environmental attributes, and Hansen et al.’s (2013) Landsat-based Global Forest Change dataset.
The connectedness of each protected cell is calculated as a weighted sum of the benefit values of all cells in the surrounding landscape weighted by the probability of dispersal associated with the least-cost path between the protected cell of interest. This probability of dispersal is a function of the permeability values of cells along the least-cost path (Drielsma et al. 2007; Santini et al. 2015). The resulting weighted sum for each protected cell is expressed as a proportion of the maximum possible sum if that cell were surrounded by a continuous expanse of protected cells within a 500km radius, thereby yielding a connectedness score for that cell between 0 and 1. The Protected Area Connectedness Index is then derived by summing these scores across all protected cells within the unit, and dividing this sum by the number of protected cells, thereby expressing overall connectedness as a proportion, also ranging between 0 and 1.
The Protected Area Connectedness Index does not currently consider the suitability of intermediate habitat on a path, or the complexities of terrain (e.g. mountain ridges). The geometry of the index favours large protected areas with internal connectedness, which is consistent with theoretical considerations.
GEO BON (2015) Global Biodiversity Change Indicators. Version 1.2. Group on Earth Observations Biodiversity Observation Network Secretariat. Leipzig. http://www.geobon.org/Downloads/brochures/2015/GBCI_Version1.2_low.pdf
Drielsma, M., Ferrier, S. and Manion, G. (2007) A raster-based technique for analysing habitat configuration: the cost-benefit approach. Ecological Modelling 202: 324-332.
Friedl, M. A., Sulla-Menashe, D., Tan, B., Schneider, A., Ramankutty, N., Sibley, A., Huang, X. (2010). MODIS Collection 5 global land cover: Algorithm refinements and characterization of new datasets. Remote Sensing of Environment 114: 168–182.
Hansen, M.C., Potapov, P.V., Moore, R., Hancher, M., Turubanova, S.A., Tyukavina, A., Thau, D., Stehman, S.V., Goetz, S.J., Loveland, T.R., Kommareddy, A., Egorov, A., Chini, L., Justice, C.O., Townshend, J.R.G. (2013) High-resolution global maps of 21st-Century forest cover change. Science 342: 850-853.
Hoskins, A.J., Bush, A., Gilmore, J., Harwood, T., Hudson, L.N., Ware, C., Williams, K.J., Ferrier, S. (2016) Downscaling land‐use data to provide global 30” estimates of five land‐use classes. Ecology and Evolution 6: 3040-3055.
Santini, L., Saura, S., Rondinini, C. (2015) Connectivity of the global network of protected areas. Diversity and Distributions 22: 199-211.
UNEP-WCMC (2016). World Database on Protected Areas User Manual 1.3. UNEP-WCMC: Cambridge, UK. Available at: http://wcmc.io/WDPA_Manual
The source data are currently unavailable for public download.
The data that went into generating the indicator are available as follows:
Land use data: https://doi.org/10.4225/08/56DCD9249B224
Landsat-based Global Forest Change dataset: http://earthenginepartners.appspot.com/science-2013-global-forest/downlo...
MODIS data: http://www.earthenv.org/
World Database on Protected Areas (UNEP-WCMC 2016): https://www.protectedplanet.net/c/world-database-on-protected-areas