Only ten percent of the global terrestrial protected area network is connected via intact land

Abstract

Land free of direct anthropogenic disturbance is considered essential for achieving biodiversity conservation outcomes but is rapidly eroding. In response, many nations are increasing their protected area estates but little consideration is given to the context of the surrounding landscape. This is despite the fact that connectivity between protected areas is critical in a changing climate 5 and mandated in international protected area targets. By utilizing the latest human pressure assessment, which shows that ~40% of the terrestrial planet is still intact, and a connectivity method, we found just 9.7% of Earth's terrestrial protected network can be considered 'connected'. On average, 11% of each nation's protected area estate is connected via intact land.As the global community commits to bolder action on abating biodiversity loss, only an 10 increased focus on landscape-scale habitat retention and restoration efforts will ensure those critical areas safeguarded for conservation outcomes will remain (or become) connected.

Functional Connectivity of the World’s Protected Areas

“…S2). For example, we found that PAI, used to assess functional connectivity, varied considerably among countries that were assigned a connectivity value of zero by the ConnIntact indicator 9 , which is used to assess the contiguity of intact natural land between PAs irrespective of animal movement (i.e., structural connectivity) (Fig. 2).…”

“…We identified concentrated flows using MMP grid cells in the 90th percentile, hereafter referred to as critical connectivity areas (CCAs). We further divided CCAs into two categories based on a threshold HFI value of 4 previously used by others 9,11,31 : "modified" CCAs where HFI ≥ 4, and "intact" CCAs where HFI < 4. We found that 97% of CCAs occur in intact areas and 3% are modified (i.e., 9.7% and 0.3% of the terrestrial realm, respectively).…”

“…ConnIntact 9 -an updated version of Protconn 22 , the currently proposed global indicator -and (3) the PA connectedness index (PARC) 59 . ConnIntact is a network-based structural connectivity approach that accounts for the number of PAs, total area of PAs, total country area and the contiguity of intact land between PAs.…”

“…Our current global system of protected areas (PAs) has been unable to slow biodiversity loss 1,2 or provide adequate coverage for many threatened species and ecosystems 1,[3][4][5][6][7] . PAs are constrained in size, ecological representation and governance 8 , and 90% or more exist within a matrix of human-dominated, fragmented land 9 that is rapidly eroding 10,11 , endangering animal movement 12,13 and survival 14 . As a result, PAs and the animal populations they contain can become isolated, interrupting the flow of vital ecological (e.g., migration, dispersal) and evolutionary (e.g., gene flow) processes that maintain populations, ecosystems and adaptive capacity [14][15][16][17] .…”

“…While these targets remained unmet by the end of 2020, post-2020 global biodiversity framework discussions continue to champion the importance of connectivity, both as a stand-alone target and integrated into other relevant targets 20,21 . To date, only a few evaluations of the connectedness of the world's PAs exist 9,22,23 and none explicitly map the functional connectivity of PAs. This research gap prevents the identification of globally important areas for wildlife connectivity and the spatially explicit assessment of potential threats to connectivity.…”