Plastic pollution is a planetary threat, affecting nearly every marine and freshwater ecosystem globally. In response, multilevel mitigation strategies are being adopted but with a lack of quantitative assessment of how such strategies reduce plastic emissions. We assessed the impact of three broad management strategies, plastic waste reduction, waste management, and environmental recovery, at different levels of effort to estimate plastic emissions to 2030 for 173 countries. We estimate that 19 to 23 million metric tons, or 11%, of plastic waste generated globally in 2016 entered aquatic ecosystems. Considering the ambitious commitments currently set by governments, annual emissions may reach up to 53 million metric tons per year by 2030. To reduce emissions to a level well below this prediction, extraordinary efforts to transform the global plastics economy are needed.

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Spatial representations of threatening processes – “threat maps” – can identify where biodiversity is at risk, and are often used to identify priority locations for conservation. In doing so, decision makers are prone to making errors, either by assuming that the level of threat dictates spatial priorities for action or by relying primarily on the location of mapped threats to choose possible actions. We show that threat mapping can be a useful tool when incorporated within a transparent and repeatable structured decision‐making (SDM) process. SDM ensures transparent and defendable conservation decisions by linking objectives to biodiversity outcomes, and by considering constraints, consequences of actions, and uncertainty. If used to make conservation decisions, threat maps are best developed with an understanding of how species respond to actions that mitigate threats. This approach will ensure that conservation actions are prioritized where they are most cost‐effective or have the greatest impact, rather than where threat levels are highest.

Aichi Target 11 has galvanized expansion of the global protected area network, but there is little evidence that this enlargement brings real biodiversity gains. We argue that area-based prioritization risks unintended perverse consequences and that the focus of protected-area target development should shift from quantity to quality.

Ensuring that protected areas (PAs) maintain the biodiversity within their boundaries is fundamental in achieving global conservation goals. Despite this objective, wildlife abundance changes in PAs are patchily documented and poorly understood. Here, we use linear mixed effect models to explore correlates of population change in 1,902 populations of birds and mammals from 447 PAs globally. On an average, we find PAs are maintaining populations of monitored birds and mammals within their boundaries. Wildlife population trends are more positive in PAs located in countries with higher development scores, and for larger-bodied species. These results suggest that active management can consistently overcome disadvantages of lower reproductive rates and more severe threats experienced by larger species of birds and mammals. The link between wildlife trends and national development shows that the social and economic conditions supporting PAs are critical for the successful maintenance of their wildlife populations.

32 Protected Area coverage has reached over 15% of the global land area. However, the quality of 33 management of the vast majority of reserves remains unknown, and many are suspected to be 34 'paper parks'. Moreover, the degree to which management can be enhanced through targeted 35 conservation projects remains broadly speculative. Proven links between improved reserve 36 management and the delivery of conservation outcomes are even more elusive. In this paper we 37 present results on how management effectiveness scores change in protected areas receiving 38 conservation investment, using a globally expanded database of protected area management 39 effectiveness, focusing on the 'management effectiveness tracking tool' (METT). Of 1934 protected 40 areas with METT data, 722 sites have at least two assessments. Mean METT scores increased in 41 69.5% of sites while 25.1% experienced decreases and 5.4% experienced no change over project 42 periods (median 4 years). Low initial METT scores and longer implementation time were both 43 found to positively correlate with larger increases in management effectiveness. Performance 44 metrics related to planning and context as well as monitoring and enforcement systems increased 45 the most while protected area outcomes showed least improvement. Using a general linear mixed 46 model we tested the correlation between change in METT scores and matrices of 1) landscape and 47 protected area properties (i.e. topography and size), 2) human threats (i.e. road and human 48 population density), and 3) socio-economics (i.e. infant mortality rate). Protected areas under 49 greater threat and larger protected areas showed greatest improvements in METT. Our results 50 suggest that when funding and resources are targeted at protected areas under greater threat they 51 have a greater impact, potentially including slowing the loss of biodiversity. 52

Recognizing that protected areas (PAs) are essential for effective biodiversity conservation action, the Convention on Biological Diversity established ambitious PA targets as part of the 2020 Strategic Plan for Biodiversity. Under the strategic goal to "improve the status of biodiversity by safeguarding ecosystems, species, and genetic diversity," Target 11 aims to put 17% of terrestrial and 10% of marine regions under PA status by 2020. Additionally and crucially, these areas are required to be of particular importance for biodiversity and ecosystem services, effectively and equitably managed, ecologically representative, and well-connected and to include "other effective area-based conservation measures" (OECMs). Whereas the area-based targets are explicit and measurable, the lack of guidance for what constitutes important and representative; effective; and OECMs is affecting how nations are implementing the target. There is a real risk that Target 11 may be achieved in terms of area while failing the overall strategic goal for which it is established because the areas are poorly located, inadequately managed, or based on unjustifiable inclusion of OECMs. We argue that the conservation science community can help establish ecologically sensible PA targets to help prioritize important biodiversity areas and achieve ecological representation; identify clear, comparable performance metrics of ecological effectiveness so progress toward these targets can be assessed; and identify metrics and report on the contribution OECMs make toward the target. By providing ecologically sensible targets and new performance metrics for measuring the effectiveness of both PAs and OECMs, the science community can actively ensure that the achievement of the required area in Target 11 is not simply an end in itself but generates genuine benefits for biodiversity.