Wildlife use and trade support the livelihoods of millions of people worldwide but also threaten thousands of species. Legal instruments, when effectively designed and implemented, can help regulate trade and mitigate negative impacts. However, activities along supply chains are rarely categorically legal or illegal, with considerable uncertainties regarding legality in the wildlife trade. These uncertainties can compromise the success of efforts to ensure, or improve, sustainability, but are often overlooked. Here, we categorize legal uncertainties in wildlife trade into three dimensions: institutional, operational, and perceptual. We explore their implications for sustainable management and discuss potential interventions to address them, drawing on examples from wildlife management and other sectors. Resolving these uncertainties can reduce unsustainable and illegal trade, strengthen traceability and enforcement, and promote equitable benefit-sharing among actors. Our findings offer actionable insights for policymakers, practitioners, and researchers to improve the clarity and effectiveness of wildlife trade management, advancing both conservation and socio-economic objectives.

Overexploitation is a major threat to biodiversity and international trade in many species is regulated through the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). However, there is no established method to systematically determine which species are most at risk from international trade to inform potential trade measures under CITES. Here, we develop a mechanism using the International Union for Conservation of Nature’s Red List of Threatened Species to identify species that are likely to be threatened by international trade. Of 2,211 such species, CITES includes 59% (1,307 species), leaving two-fifths overlooked and in potential need of international trade regulation. Our results can inform deliberations on potential proposals to revise trade measures for species at CITES Conference of the Parties meetings. We also show that, for taxa with biological resource use documented as a threat, the number of species threatened by local and national use is four times greater than species likely threatened by international trade. To effectively address the overexploitation of species, interventions focused on achieving sustainability in international trade need to be complemented by commensurate measures to ensure that local and national use and trade of wildlife is well-regulated and sustainable.

Although some sectors have made significant progress in learning from failure, there is currently limited consensus on how a similar transition could best be achieved in conservation and what is required to facilitate this. One of the key enabling conditions for other sectors is a widely accepted and standardized classification system for identifying and analyzing root causes of failure. We devised a comprehensive taxonomy of root causes of failure affecting conservation projects. To develop this, we solicited examples of real-life conservation efforts that were deemed to have failed in some way, identified their underlying root causes of failure, and used these to develop a generic, 3-tier taxonomy of the ways in which projects fail, at the top of which are 6 overarching cause categories that are further divided into midlevel cause categories and specific root causes. We tested the taxonomy by asking conservation practitioners to use it to classify the causes of failure for conservation efforts they had been involved in. No significant gaps or redundancies were identified during this testing phase. We then analyzed the frequency that particular root causes were encountered by projects within this test sample, which suggested that some root causes were more likely to be encountered than others and that a small number of root causes were more likely to be encountered by projects implementing particular types of conservation action. Our taxonomy could be used to improve identification, analysis, and subsequent learning from failed conservation efforts, address some of the barriers that currently limit the ability of conservation practitioners to learn from failure, and contribute to establishing an effective culture of learning from failure within conservation.

D'Cruze et al. (2022) and Frank and Wilcove (2022) suggest that Challender et al. (2021) misrepresent their research. We reiterate that our intention was not to denigrate any particular study; instead, we aimed to draw attention to contemporary issues in wildlife trade research and highlight ways for research to better inform policy processes. Here, we respond to the points raised in these articles. D'Cruze et al. suggest that we were incorrect to deduce from Harrington et al. (2019) that their position is that “use/trade [in Asian otters as exotic pets] constitutes a threat to the species or is detrimental to wild populations.” This is despite the title of that article being “Popularity of pet otters on YouTube: evidence of an emerging trade threat.” It is difficult to reconcile this title and statements within the article with the assertion that Harrington et al. did not conclude that the pet trade posed a threat to wild populations of Asian otters. However, our primary concern is that Harrington et al.’s analysis of trends in popularity of social media videos of pet otters makes the jump to strongly endorsing an international trade policy (specifically, including two otter species in CITES Appendix I) despite the authors acknowledging that there is no evidence of a link between social media trends and trade trends. Trade bans via CITES may be considered as a sensible precautionary measure by some, but in some instances, they may do more harm than good for species (Challender et al., 2021). To avoid this scenario, the risks and benefits of such proposals should be fully assessed (Cooney et al., 2021). Regarding CITES source code “I,” users of data with this source code should be aware that CITES Parties use this code in various ways and therefore be clear whether data refer to illegal trade or legal (re-)exports of previously seized specimens. Otherwise, trade is likely to be mischaracterized (Lopes et al., 2017). A better method of characterizing illegal trade in CITES-listed species would be to use other available databases (see Supporting Information in Challender et al., 2021) and CITES source code “I” data that can be categorically identified as referring to illegal trade. Regarding Can et al.’s (2019) conclusion that “risks posed by pathogens…associated with the wildlife trade should not be under-estimated,” we agree and add that neither should they be overestimated. Both carry the risk of misleading policy processes. D'Cruze et al. also argue that their errors relating to transaction frequency in CITES trade data were minor and do not fundamentally alter their conclusions. While we acknowledge this, our concern remains that if mistakes made in published articles on wildlife trade are not addressed, there is a risk that they will be perpetuated by other authors in the future. We agree with Frank and Wilcove (2022) that the IUCN Red List of Threatened Species (hereafter “Red List”) can be used to inform the potential adoption of trade measures in CITES. Indeed, the Red List has informed CITES processes since its inception, and the potential for closer alignment is currently being explored. However, Frank and Wilcove (2022) claim that Challender et al. (2021) believe that “…CITES protection (via Appendices I and II) should be reserved for vanishing species whose main threat is international trade …” and cite the Convention text as justification for including species in CITES when trade may only be a contributing threat. They misrepresent our main point, namely that, based on lessons learnt in preceding decades (Cooney et al., 2021), species should be listed based on evidence that doing so is likely to contribute to (and not potentially undermine) their conservation. The precautionary principle which underpins conservation policy is not unidirectional and it cannot be assumed that tighter regulation of international trade, including bans, is always the most precautionary policy option. One of our major criticisms of Frank and Wilcove (2019) was that their recommendations were poorly developed, overlooking critical factors that would impede real-world adoption (Challender et al., 2021). There is far more exposition and “nuance” in their response to our commentary than their original article. We encourage researchers suggesting wildlife trade policy reforms to recognize and address the potential challenges in realistic terms, not least to ensure credibility with those who make and implement policy. Finally, we do not claim in Challender et al. (2021) that specific studies have misled policy; however, where wildlife trade data are interpreted inaccurately in research articles, there is potential to mislead policy processes, and to undermine the role of academic research in informing these processes. We would welcome collaboration with researchers interested in working with us to develop best practice guidelines that ensure that wildlife trade policy is based on the best evidence, appropriately interpreted. D.C. and E.J.M.G. acknowledge funding from the Oxford Martin Programme on Wildlife Trade and the UK Research and Innovation's Global Challenges Research Fund (UKRI GCRF) through the Trade, Development, and the Environment Hub project (project number ES/S008160/1). A.H. is funded by a Kadas Fellowship at Worcester College, Oxford. The authors declare no conflict of interest. All authors contributed to the conception, writing, editing, and reviewing of the manuscript. No primary data were collected for this manuscript and an ethical review process was not undertaken. No primary data were collected for this manuscript. No primary data were collected for this manuscript.

If parties to the Convention on Biological Diversity (CBD) and their partners are to report effectively on progress against national, regional and global biodiversity conservation goals, data will need to be collected at multiple levels. Global data sets, many gathered using remote sensing, offer partial solutions but need to be complemented by field-level observations to provide the resolution necessary to track conservation measures in a meaningful way. This paper summarises efforts made by the conservation organisation WWF, working with partners, to integrate 10 indicators of relevance to CBD parties into its global monitoring system and to use global data sets and data from field programmes to determine progress against multi-level goals and to assess programme performance and impacts. Integration of in-situ and ex-situ data into reporting dashboards tailored to WWF's needs allowed some degree of assessment of progress and adaptive management of the programme portfolio. Indicator trends were most favourable (on track) for protected area (PA) coverage and market share of sustainable commodities, and least favourable (worsening) for species offtake, species populations, wildlife trade, habitat fragmentation and Ecological Footprint. The most useful indicators – which could be disaggregated to provide trends at local levels relevant to WWF field programmes – were species populations, habitat cover and fragmentation, PA coverage and PA management effectiveness. However challenges remain if local and global monitoring objectives are to be aligned, including the need for increased collection of data by field projects, improved harmonisation of indicators, and greater sharing of data in formats of use to practitioners. We advocate wider adoption by governments and civil society organisations of indicators with the dual function of tracking delivery of CBD Aichi Targets as well as monitoring national, regional and ecoregional level conservation programmes, and urge more NGOs and academic bodies to support capacity building and data collection.

In 2002, world leaders committed, through the Convention on Biological Diversity, to achieve a significant reduction in the rate of biodiversity loss by 2010. We compiled 31 indicators to report on progress toward this target. Most indicators of the state of biodiversity (covering species’ population trends, extinction risk, habitat extent and condition, and community composition) showed declines, with no significant recent reductions in rate, whereas indicators of pressures on biodiversity (including resource consumption, invasive alien species, nitrogen pollution, overexploitation, and climate change impacts) showed increases. Despite some local successes and increasing responses (including extent and biodiversity coverage of protected areas, sustainable forest management, policy responses to invasive alien species, and biodiversity-related aid), the rate of biodiversity loss does not appear to be slowing.

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) came into effect in 1975 to protect certain species of wild fauna and flora against over-exploitation through international trade. Determining which trade is detrimental to the survival of species in the wild can be a major difficulty in the implementation of CITES by national authorities, partly due to limited knowledge and understanding of the species’ biology, management, and the impacts of harvesting. Some of this knowledge could be acquired through targeted scientific research. However, to date there exists no general overview of the current use of biological information in determining detriment in CITES to help scientists identify research priorities. For an international meeting in 2008, over 100 scientists and regulators compiled 60 case studies covering a wide range of CITES-listed taxa, outlining how information on the biology, harvesting and management might be used to determine whether international trade is detrimental. We used these case studies, workshop conclusions, and other published literature, to identify 10 potential research directions for the scientific community which, if addressed, could greatly assist in the making of Non-Detriment Findings. We hope that this will encourage more scientists to study CITES-listed species, and foster more collaboration between research scientists, CITES national authorities, CITES technical committees and local communities. The case studies highlight a general need for advice on how to identify and manage levels of risk involved when assessing possible detriment, and for advice on assessing detriment under complex harvesting scenarios such as when multiple species, or parts of individuals, are harvested. Broadly, they highlight an opportunity for scientists to further develop a body of scientific studies that propose, refine and adapt methods for assessing detrimental trade in CITES-listed taxa. Comparisons within life-form groups indicated the potential for the identification of practical advice that could apply to groups of taxa. The case studies highlighted a widespread need for more information gathering studies of CITES-listed taxa such as the broader impacts of harvesting on populations and ecosystems, and the potential long-term evolutionary impacts. The case studies also highlighted the need for practical advice on how to implement adaptive management programmes and for research into enterprises based on the harvesting of CITES-listed species from the wild.

Many protected area (PA) systems have developed in response to socio-economic and aesthetic criteria and need to be modified to increase their conservation value. National gap analyses are an important step in describing and addressing this problem, so we sought to determine the representativeness of English PAs devoted to biodiversity conservation by using Natural Areas (NAs), elevation and PA boundary data. We found that National Nature Reserves (NNRs) and Sites of Special Scientific Interests (SSSIs) cover only 6.3% of England and are generally small, with respective median areas of 1.1 and 0.2 km2. The English PA system under-represents lowland areas and provides a median level of 2.5% protection for the NA types, with seventy nine per cent of NA types having less than 10% protection. Therefore, we suggest that England's PA system needs to be expanded, although this would probably entail modification of existing legislation to increase involvement by landowners. We also compare our results with previous appraisals that used species distribution record data and suggest that landscape-level analyses may give a more accurate and less positive assessment.