Measuring progress in marine protection: A new set of metrics to evaluate the strength of marine protected area networks

Abstract

24Marine protected areas (MPAs) have proven to be a valuable tool for both promoting the 25 sustainable use of marine resources and long-term biodiversity conservation outcomes. Targets for 26 marine protection under the Convention on Biological Diversity have seen rapid growth in MPAs 27 globally, with progress judged using targets for total area protected rather than evaluating growth 28 based on the capacity to protect biodiversity. The value of a MPA network to biodiversity 29 conservation depends on a range of attributes of both individual MPAs and portfolios of MPAs, 30 which are not captured by simple area-based targets. Therefore, a clear and efficient set of metrics 31 are needed to effectively evaluate progress towards building MPA networks, considering the 32 representation and adequacy of protection for biodiversity. We developed a universally applicable 33 set of metrics that can evaluate network structure in relation to its capacity to conserve marine 34 biodiversity. These metrics combine properties of effective individual MPAs with metrics for their 35 capacity to function collectively as a network. To demonstrate the value of these metrics, we apply 36 them to the Australian MPA network, the largest in the world. Collectively, the indicators suggest 37 that while Australia has made significant progress in building a representative and well-structured 38 MPA network, the level of protection offered to marine biodiversity is generally low, with 39 insufficient coverage of no-take MPAs across many bioregions. The metrics reveal how the current 40 value of the MPA network could be greatly increased by reducing the prevalence of multi-use zones 41 that allow extractive activities known to negatively impact biodiversity. • Not all MPAs are equal, therefore total area is an inadequate indicator of progress. 48• Indicators of progress can draw on attributes of effective MPAs and MPA networks. 49• We developed a suite of metrics to evaluate MPA network structure and performance. 50• Strengths of the Australian MPA network: well-structured and representative. 51

Protected area downgrading, downsizing, and degazettement (PADDD) in marine protected areas

“…To conduct a preliminary investigation of PADDD in MPAs, we documented marine PADDD events systematically in Australia by reviewing all relevant legal documents (enacted or proposed between 2007 to 2019); we identified PADDD opportunistically in other countries [13,16] (See Supplementary Text, Methods and Results). Systematic data collection focused in Australia due to the high incidence of recent Australian marine PADDD events [17], including a large downgrade event in 2018 that affected several MPAs simultaneously (hereafter referred to as the 2018 Australian Systemic Downgrade) ( Table 1). Australia has rapidly expanded its MPA coverage and is widely viewed as a global leader in MPA implementation [18].…”

“…In this study, we included MPAs that fall exclusively in the ocean, as well as PAs spanning the intertidal zone when the PADDD event was enacted or proposed in the marine portion of the PA. This analysis combined published data on PADDD (including PADDD events in MPAs from [13,17]), with previously unpublished data. To identify marine PADDD events from previously published data, spatial data from [13] was clipped to the World Vector Shoreline to exclude PADDD events that overlapped exclusively with land.…”

“…The first PADDD events in the Australian MPA network were enacted in 2011 following a formal rezoning implemented after a change in government under New South Wales jurisdiction [17]. Most enacted PADDD events in Australian MPAs were systemic (n=37), whereby one legal action affected multiple MPAs simultaneously.…”

Protected area downgrading, downsizing, and degazettement as a threat to iconic protected areas

“…These studies reveal that simple comparison of historical versions of PA databases may generate a large number of false positives (i.e., areas that appeared to be removed from protection due to version inconsistencies or boundary corrections instead of true legal changes [Cook et al 2017;Lewis et al 2019]), highlighting the value of systematic, in-country archival research. Future research should also focus on marine PADDD, which remains poorly documented despite a recent wave of PADDD proposals targeting marine protected areas in Australia (Rebgetz 2017;Roberts et al 2018) and the United States (Milman 2018).…”

South Africa’s newly approved marine protected areas have increased the protected modelled habitat of nine odontocete species

“…Countries with coastlines are introducing new legislation to increase the numbers and sizes of marine protected areas (MPAs) to reduce biodiversity loss and conserve ecosystem functioning (Edgar et al 2014, Roberts et al 2018. The Convention on Biological Diversity (CBD), through decision X/2 (reinstituted in 2010), set out 20 Aichi biodiversity targets to reduce biodiversity loss in the marine and terrestrial environments (CBD 2010, 2012, Pereira et al 2013, Edgar et al 2014, Thomas et al 2014, Roberts et al 2018. Notably, Aichi target number 11 encourages member states to increase representative MPAs to a total of 10% of their Exclusive Economic Zone (EEZ) by 2020 (Thomas et al 2014).…”