Opinion

What Conservation Does Laurent Godet1,3,* and Vincent Devictor2,3 New agendas for conservation are regularly proposed based on the ground that existing strategies are overly pessimistic, restricted to biodiversity hotspots, and inappropriate to halt biodiversity loss. However, little empirical evidence supports such claims. Here we review the 12 971 papers published in the leading conservation journals during the last 15 years to assess what conservation actually does. Although conservation research is affected by specific bias, conservation is playing a major role in providing empirical evidence of human impacts on biodiversity. Encouraging biodiversity comebacks are also published and a wide range of conservation tools, beyond the development of protected areas in wilderness areas, are promoted. We argue that finding new routes to conservation is neither necessary nor sufficient to halt biodiversity loss.

Highlights We test how conservation documents biodiversity status, threats, and solutions. Many threats to biodiversity are reported as well as some taxonomic bias. However, biodiversity comebacks are documented as well as effective conservation tools. New routes to conservation are neither necessary nor sufficient to halt biodiversity loss.

The Agenda of Conservation Science Discredited Biodiversity loss is not decelerating [1], either in the terrestrial [2] or marine biotas [3] and affects most taxa, particularly birds and mammals [4]. In addition to its velocity, one of the features of the current situation lies in its anthropogenic origin [5]. This critical transition has been labeled as ‘Anthropocene’ by scientists, policymakers, and the broader public [6]. However, these conditions were already recognized more than three decades ago, when they led to the emergence of the discipline of conservation biology, designated as ‘crisis discipline’ [7], whose concepts and practices revolved around a fundamental conflict between protecting nature and the acceleration of human impacts on biodiversity [8]. However, the relevance of conservation agenda has subsequently been challenged by three main line of arguments. The first one argues that accumulating evidence of negative impacts of human activities is counterproductive [9]. According to this view, conservation conveys overly pessimistic messages and the discipline should review its messages of despair and hopelessness [10,11]. The second uses the ongoing negative trend in biodiversity loss to claim that traditional conservation tools, and mainly protected areas (see [12]), are insufficient to slow down the biodiversity crisis [13]. Finally, conservation is regularly undermined as being restricted to (tropical) biodiversity hotspots instead of paying attention to places where most humans live and work [11]. 1

Such criticism remains, however, rhetorical and uninformed by empirical analysis. This has generated skeptical environmental postures as popularized by the publication of Lomborg’s book in 2001 [14] and the passionate debate it triggered [15–17]. Skeptical environmentalism already suggested that environmental problems, including biodiversity loss, lead to overly pessimistic claims and ineffective policies and are correlated with poverty. Therefore, according to this view, environmental challenges should mostly reduce to ensuring economic and social development. As already discussed by Doak et al. [18], this ancient rhetoric is surprisingly recently used again by proponents of ‘new’ conservation movements as a justification to define new directions to the field. In particular, this proposal suggests that conservation biology should 720

Trends in Ecology & Evolution, October 2018, Vol. 33, No. 10 © 2018 Elsevier Ltd. All rights reserved.

https://doi.org/10.1016/j.tree.2018.07.004

CNRS, Université de Nantes, UMR LETG, B.P. 81223, 44312 Nantes Cedex 3, France 2 CNRS, ISEM, Université de Montpellier, IRD, EPHE, 34095 Montpellier Cedex 05, France 3 Both authors contributed equally to this work

*Correspondence: [email protected] (L. Godet).

endorse a more integrative approach (and thus be called ‘conservation science’) to combine human development and biodiversity issues. Yet, if uncritically explored, this litany may create false dichotomies (between old and new and/or conservation science and conservation biology). Indeed, conservation was meant, in its origin, to be a synthetic and multidisciplinary science involving natural and social sciences, and dealing with natural resource fields such as public policy, management, or forestry [7]. Overall, whether conservation needs to be reframed toward even more compromise between biodiversity protection and human activities should be further explored and anchored in empirical investigations rather than limited to wishful thinking. In their paper ‘What is the future of conservation?’, Doak et al. [18] have already critically assessed the major arguments used by those pleading for the need to find new directions to conservation. They convincingly show that this rather dramatic proposal rests on unchecked and dubious assumptions (e.g., past conservation has been a failure, or conservation should be aligned with people’s interest, i.e., economic issues). However, a systematic review of what is achieved in academic research is missing in this recurrent debate. What have we learnt from the thousands of papers that have accumulated in conservation journals? Is conservation biology condemned to report biased biodiversity status? Are threats reported by conservation biologists exaggerated and solutions undermined? Here, we review each of the 12 971 papers published from January 2000 to February 2015 in the nine leading conservation science journals, in order to investigate how conservation contributes to produce knowledge regarding the status and threats of biodiversity and the solutions to its loss.

Identifying the Status, Threats, and Solutions Considered by Conservation Science Scrutinizing the Academic Conservation Corpus We analyzed the titles, abstracts, and, if necessary, full-texts of all scientific papers published from January 2000 to February 2015 in the nine leading international conservation science journals. We restricted this analysis to journals corresponding to the field ‘conservation’ according to the Web of Science: Animal Conservation, Biodiversity and Conservation, Biological Conservation, Conservation Biology, Conservation Letters, Diversity and Distributions, Environmental Conservation, Journal for Nature Conservation, and Oryx (n = 12 971 papers). See Supplemental Material S1 online for details of the journal selection process. Defining Status, Threats, and Solutions We distinguished three categories of dominant justification to each paper: those dealing with biodiversity ‘status’, those exploring ‘threats’ to biodiversity, and others proposing ‘solutions’ to biodiversity issues. We focused on paper using either empirical data or meta-analysis. Other papers, not exploring one of the aforementioned categories or not dealing with biodiversity issues (e.g., about conservation funding, new conservation policies), were classified as ‘other’. The ‘Status’ category was defined as papers that report the state of biodiversity, without any direct causal link with a specific threat. The ‘Threats’ category was defined as papers that report threats to biodiversity (i.e., studies which identify a causal link between a pressure and any biodiversity component). The ‘Solutions’ category was defined as papers that report the influence of any conservation tool on biodiversity. Papers proposing fuzzy conservation measures that cannot be used directly by practitioners (such as ‘large patches of forests need to be protected’, or ‘fragmentation has to be avoided’) were included in the ‘other’ category. Trends in Ecology & Evolution, October 2018, Vol. 33, No. 10

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The other category also included papers reporting equivocal status of any biodiversity component (e.g., landscape fragmentation has positive effects on one taxon but negative effects on another), methodological papers, descriptive papers (e.g., species ecology), opinions, epistemological studies, perspectives in conservation biology, development of indicators, theoretical studies, improvement of knowledge of biodiversity, and editorials or book reviews. Papers classified in the three main categories (status, threats, and solutions) were then assigned to a finer and hierarchical classification. We distinguished four types of status (good status, potential good status, bad status, and potential bad status, and then subdivided them into different subcategories); 10 types of threats (subdivided into 20 different subcategories); and 14 types of solutions (subdivided in four subcategories: failure, insufficiency, proposal, and success). Note that the three main categories (status, threats, and solutions) were defined a priori, but the subcategories emerged a posteriori from the initial reading of the papers, and were gradually modified. The classification was checked twice, independently by the two authors of this paper, to confirm the match between papers and categories. The exact description of each category and subcategory is given in Supplemental Material S2 online. In addition to this typology, various additional characteristics of each study were distinguished. Geographical location: continents (Africa, Antarctica, Asia, Europe, North America, South America, and Oceania); oceans/seas (Arctic Ocean, Atlantic Ocean, Baltic Sea/North Sea, Caribbean Sea, Pacific Ocean, Indian Ocean/Persian Gulf, and Mediterranean Sea); and other (diverse continents/oceans/seas, worldwide, and ex situ studies). Mexico and Central America were included in South America. Ecological system considered: single species, multispecies, local ecosystems, or global scale. And finally, the taxonomic group studied: amphibians, birds, mammals, fish, freshwater invertebrates, marine invertebrates, terrestrial non-insect invertebrates, insects/arachnids, reptiles (excluding marine turtles), marine turtles, plants, lichens, fungi/bryophyte/algae, mix of species, and other species.

Diversity and Distribution of Status, Threats, and Solutions in Space and among Taxonomic Groups From January 2000 to February 2015, the nine journals published 12 971 papers. The annual publication rate increased from 2000 to 2014, partly due to the appearance of three new journals: Conservation Letters, Diversity and Distributions, and the Journal for Nature Conservation. The year 2015 was not included in this analysis as data were not available for the full year (linear trend: +35 papers a year, F1,13 = 49.25, P < 0.01, R2 = 0.79). The analysis showed that 76% of papers (9844) could not be classified in the three main categories (status, threats, or solutions) and were therefore included in the ‘other’ category. Of the 3127 remaining papers, 34% documented the specific status of a biodiversity component (among which 125 and 767 papers were, respectively, showing ‘bad’ and ‘potentially bad’ status; 147 and 11 papers ‘good’ and ‘potentially good’ status); 31% reported threats to biodiversity [among which most of the papers were related to habitat changes (352), overexploitation of the resources (217), and the impact of invasive species (133)]; and 35% reported solutions [mostly related to protected areas (207), followed by sustainable conservation measures (182), species translocation (154), and habitat restoration or creation (118)] – see Figure 1. Among the solutions, we can notice that proposals of solutions (in blue on Figure 1) not only dominated the studies but also that most of the papers proposed a sustainable use of the resources (133), followed by species-specific management (97), species translocation (95), and 722

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Status (1050 papers) Family of category

Category

Bad state

Bad state 125

125 Potenal bad state

Potenal bad state 767

767 Good state

87

Spontaneous comeback

Biodiversity resistance-resilience 60

147 Potenal good state

Potenal good state 11 11 0

50

100

150

650

700

Habitat degradaon

263

Threats (983 papers) Category

Family of category Habitat change

Habitat destrucon 89

352

69 Animal hunng 61 Fishing Overexploitaon

53 Trading

217

19 Poaching 15 Earth resource exploitaon Invasive species Invasive species 133 133 27 Human disturbance 27 Human selements (roads and railways)

Human selements and presence

20 Human selements (excluding roads and railways)

100

19 Conflicts between humans and nature 7 Conflicts between humans 50 Agriculture

Agriculture, forestry, aquaculture 8 Forestry 60

2 Aquaculture 19 Genec limitaon Ecological

15 Catastrophic natural events

47

8 Other ecological causes 55 Predaon

Diseases

32 Diseases 32 Climate change 20 Climate change 20 Polluon 18 Polluon 18 Human abandonment 44 Agricultural land abandonment

4

0

50

100

150

200

250

Soluons (1094 papers) Family of category

Category

Protected areas

18

59

40

Sustainable use 5 Translocaon 11

Species-specific management 3

29

Control of invasive species or pathogens 1

70 24

37

Landscape/seascape management Species protecon 21

40

26

Failure (46)

43 43

43

Social or economic

62 53

53

Limitaon of human acvies

118

10 110

97 70

Idenficaon of hot areas for conservaon

154

48

85

182

44

95

Habitat restoraon–creaon 3 1

207

90

133

Insufficiency (42)

26 Proposal (718)

Other or mix of measures 11 11 Success (288)

Ex situ conservaon 343 10 Policy 5 5 0

50

100

150

200

250

Figure 1. Number of Papers within Each Category of Status of Biodiversity, Threats on Biodiversity, and Solutions to Conserve Biodiversity. Trends in Ecology & Evolution, October 2018, Vol. 33, No. 10

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habitat restoration or creation (85), while the proposal of solutions related to protected areas (namely extension or creation of protected areas) gathered only 59 papers. Moreover, focusing only on those studies demonstrating the insufficiency of conservation solutions (in black on Figure 1), we found that most papers conclude that protected areas are not enough (40 papers among the 207 papers on protected areas), while the insufficiency of other types of solutions was much less numerous. Mapping the study sites of all 3127 papers revealed their uneven geographical distribution (Figure 2). Only 10% focused on oceans and seas, compared with 85% of terrestrial studies. The remaining 5% examined both terrestrial and marine areas, or were not linked to a particular area. Focusing on papers assessing the status of biodiversity, we found that studies conducted in Europe were the most numerous (64), followed by Asia (46) and Africa (46), North America (35), South America (32), and, far behind, Oceania (9). More studies documented a good status of biodiversity in Europe, Africa, and South America, contrary to the other continents. Focusing on papers reporting threats to biodiversity, a comparable number of studies were located in Asia (182), Europe (160), South America (154), North America (148), while only 64 were located in Oceania. Wherever the studies were conducted, habitat change remained the major threat reported, either followed by the overexploitation of resources, the impact of invasive species, or the influence of human settlement–presence (in slightly different proportions). Finally, most of the papers dealing with conservation solutions were related to study sites located in Europe (296), followed by North America (178), Asia (132), Africa (127), Oceania (108), and South America (104). Wherever the studies were conducted, proposal of solutions gathered the largest number of papers, followed by papers documenting success, and, far behind, those documenting failures and insufficiencies. If most of the papers documenting a conservation status (75%) or conservation solutions (55%) were focused on a single species, papers related to different species dominated the literature related to threats to biodiversity. Looking at the single-species studies, most of the papers focused on birds and mammals (Figure 3).

The Diversity and Effectiveness of Conservation Solutions Our review reveals a wide range of conservation solutions, with numerous types of solutions ranging from traditional conservation tools such as protected areas and rather ‘technical’ solutions (species translocation, habitat restoration–creation, species-specific management, etc.), to ‘human-friendly’ measures such as promoting a sustainable use of natural resources, or social and economic solutions rather than restricting conservation strategies to nature protection. If protected areas remain the most documented solutions, studies promoting a sustainable use are taking the second place and even the first place if we only focus on the proposals of solutions. Contrary to what is advocated by new conservationists, it thus suggests that human-friendly solutions are already commonly proposed by the scientific literature. There is probably a bias toward reporting or not reporting failures of conservation tools, although we are unable to document in what direction our data can be biased. We may expect that a failure of a conservation tool is likely to be more reported than a success because the latter is expected and may be less appealing to journals. At the opposite, we also may expect that conservation biologists are reluctant to document conservation failures because it is potentially much more controversial. Moreover, it is probably more difficult to publish a study reporting no effect of a conservation tool (what corresponds to a failure), as this may correspond either to a real inefficiency or to an impossibility of showing significant effects with the data used. Considering this, we identified few studies reporting failures (only 46), against 288 724

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Status

N Europe (64)

Bad status

Asia (46)

North America (35)

Good status Region (number of papers) Carib. Sea (8)

Pacific Ocean (8)

Atlan c Ocean (4)

Africa (46)

Indian Ocean (8)

0

4000 km

Oceania (9)

South America (32)

Threats

N Europe (160)

Habitat change

Asia (182)

North America (148)

Overexploita on Invasive species

Pacific Ocean (41)

Carib. Atlan c Sea Ocean (19) (12)

Africa (132)

Med. Sea (10)

Indian Ocean (15)

Human se lement–presence Agriculture aquaculture and forestry Ecological Oceania (64)

Disease Other

0

4000 km

South America (154)

Region (number of papers)

Solu ons

N Europe (296)

North America (178)

Pacific Ocean (37)

Failure Insufficiency Asia (132)

Carib. Sea (9)

Success Med. Sea (10) Atlan c Ocean (19)

Region (number of papers)

Africa (127) Indian Ocean (20)

0

4000 km

Proposal

Oceania (108)

South America (104)

Figure 2. Spatial Distribution of Papers Reporting Status of Biodiversity, Threats on Biodiversity, and Solutions to Conserve Biodiversity. Carib. Sea, Caribbean Sea; Med. Sea, Mediterranean Sea.

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Status Mammals Birds Plants Amphibians 75%

Reples (excluding marine turtles) Insects and arachnids Marine turtles Fish Non-insect terrestrial invertebrates Marine invertebrates Freshwater invertebrates

24%

Fungi, bryophytes, algae 0

50

100

150

200

0

50

100

150

200

0

50

100

150

200

Threats Mammals Birds 35%

Reples (excluding marine turtles) Plants Amphibians Insects and arachnids Fish Marine invertebrates Freshwater invertebrates

52%

Non-insect terrestrial invertebrates Mulspecies Lichens Fungi, bryophytes, algae 10%

Soluons Mammals Birds Reples (excluding marine turtles) 55%

Plants Amphibians Insects and arachnids Fish Marine invertebrates Freshwater invertebrates

30%

Non-insect terrestrial invertebrates Lichens 8% 7%

Fungi, bryophytes, algae

Species Mulspecies Habitats Biodiversity and Earth

Figure 3. Proportion of Papers Included in Status of Biodiversity, Threats on Biodiversity, and Solutions to Conserve Biodiversity, According to the Group Considered, and, for Papers Dealing with Only One Species, Number of Papers by Taxonomic Group.

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reporting successful measures. A total of 90 studies reported the success of protected areas, 18 their failures, and 40 their insufficiency, suggesting that although protected areas are not a panacea, they still represent a key strategy for the success of specific conservation goals. Moreover, conservationists seem to be aware and critical toward the issues protected areas may raise rather than promoting this tool blindly.

Diversity in Study Areas and Species We found great diversity in focus regarding geographical areas and species. As it has been reported elsewhere (e.g., [19–23]), more studies have been conducted in terrestrial than marine systems. Most studies were species specific, and essentially focused on birds and mammals. This taxa bias was demonstrated by Amori and Gippoliti [24]. It continues to be used to justify the revision of conservation agendas, specifically to take the focus off charismatic species and biodiversity hotspots, and instead pay attention to the rest of the planet, including places where humans live [11]. Our review partly challenges this view. Most studies are conducted in European developed countries, far from tropical biodiversity hotspots. Moreover, these biases provide support for even more effort being given to broadening, rather than restricting the scope of conservation.

Realistic Conservation: Beyond Pessimism and Optimism Investigating the past, present, and future of conservation science needs empirical support. Assessing its effectiveness should rest on empirical studies that make an objective evaluation of the failure and success of conservation actions [25–27]. Long-term progress toward the global objective of reducing biodiversity loss has led to massive efforts dedicated to the inventory, survey, and monitoring of biological components in space and time. Lists of biodiversity indicators (e.g., the Red List [28] or the Living Planet Index [29]) are regularly updated by work that is supported by the Convention on Biological Diversity [30]. Nevertheless, we lack a clear overview of what knowledge is actually produced by conservation science. Therefore, our objective was to paint a general picture of what conservation actually does in terms of knowledge production related to the status, threats, and solutions for the biodiversity crisis. Overall, our review is consistent with a realistic picture, which is neither overly pessimistic nor optimistic. By ‘realistic’ we of course do not mean that conservation science is free from any bias or depicts the ‘reality’ regarding the state of biodiversity. On the contrary, we document clear uneven distributions of research efforts in space and among taxonomic groups. Besides, conservation biology is not meant to substitute other and complementary initiatives tracking biodiversity trends: the global and regional trends of biodiversity loss are not primarily reported by conservation studies as those considered in our paper but rather by constant and regularly updated efforts of environmental nongovernmental organizations [e.g., World Wildlife Fund (WWF) or International Union for Conservation of Nature (IUCN) reports]. We found that in academic journals, many local and independent but empirically supported papers are still documenting threats, and among the papers documenting a status of a biodiversity component, many report a potential bad state. This highlights the accumulation of empirical evidence of degradation. Similar findings were revealed by Bini et al. [31] in 2004, suggesting that there is no sign of significant improvement in the more than 10 years that have passed. We also found that the main threats were, in decreasing order generated by, habitat change, overexploitation, and invasive species. This picture is consistent with the well-documented ‘evil quartet’ [32] of the main threats to biodiversity, and cannot be considered as resulting from the failure of conservation concepts and actions per se.

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Whether, and how, conservation science should communicate bad news is controversial. Garnett and Lindenmayer [9] argue that developing a narrative focused on mass extinction through the accumulation of bad news could be counterproductive. Recently, specific proposals, such as ‘green lists’ and reporting good news, have been proposed. Authors who plead for the development of ‘a new conservation science’ go further, and consider traditional conservation as overly pessimistic [11,33]. They advocate the need to endorse a ‘more optimistic, human-friendly vision’ [11], and to recognize that nature is resilient [33], even when faced with the most powerful human disturbances [11]. By contrast, others have argued that focusing on good news could obscure the need to adapt to major changes, and fail to acknowledge the conflict between human activities and the need for nature protection [34]. Our review suggests that aside from any personal or ideological position, there is no particular reason to downplay the worrying messages delivered by conservation sciences [35], or ignore the situation is degrading worldwide (e.g., [36]). The pessimistic view is however partly counterbalanced by the reports of good status of biodiversity components we found. Actually, focusing on the status regardless of the threats, we even found a larger number of papers documenting a good status than a bad status in different areas (Europe, Africa, and South America). The progressive return of wildlife is, for example, documented in Europe [37] where the comeback of large carnivores (wolf, brown bear, lynx, and wolverine) highlights that the protection and welcoming of large species is possible [38]. Our study also highlighted the very large number of proposals of solutions. These studies argue that the application of the methods they develop could enhance the future state of biodiversity. Finally, the large number of papers classified as ‘other’ (76%) also reveal that conservation biology, as a discipline, tends to develop knowledge and methods related to conservation issues, rather than making clear statements with respect to biodiversity status, threats, or conservation solutions. Among those papers, many opinion papers or epistemological studies also contribute to generate important debates, contradictory arguments, and reflexive viewpoints. These, far from reflecting a useless scientific research, are rather signs of good scientific activity. Although it is beyond the scope of this paper, note that the ‘other’ category gathers different subcategories that could be explored deeper in a future bibliographic analysis. It could be relevant to distinguish on the one hand the papers which can be considered as irrelevant for our analysis (e.g., not dealing with biodiversity issues, methodological papers, descriptive papers, opinions, epistemological studies, perspectives in conservation biology, development of indicators, theoretical studies, improvement of knowledge of biodiversity, and editorials or book reviews) and on the other hand the papers related to insufficient information (e.g., equivocal status or fuzzy conservation measures). Note that our framework is reflecting the inherent biases affecting scientific publication. For instance, stable biodiversity status, harmless anthropic impacts, and ineffective conservation solutions are probably more difficult to publish. The extent to which including those overlooked studies would change our conclusions is difficult to know. However, conservation legitimacy and credibility would clearly gain from higher transparency in the publication of what is working or not. We think that evidence-based conservation is a good step in that direction [39]. Access to unpublished reports or promoting higher visibility of unexpected conservation results should also be facilitated. The need for evidence-based conservation was defended on the ground that conservation practice is ‘based upon anecdote and myth rather than upon the systematic appraisal of the evidence’ [39]. A specific database collating effective or ineffective actions can increase the likelihood to find the best solution (or avoid the worth) to a given specific issue. This 728

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would allow finer analysis on what contributes to conservation success and failure and their respective timing. For instance, it is likely that for some specific groups a delay is necessary between a given conservation action and the first positive signs. The extent to which this reveals what problems may be more reversible in specific situations could then be scrutinized.

Concluding Remarks The aim of our study was to take a step back from current, simplistic, ideological positions, and investigate the scientific conservation literature. In doing so, we do not claim to contribute to classical ethical debates on conservation motives (e.g., as in the long-lasting discussions about wilderness and intrinsic values) or to more recent initiatives on global land sparing or sharing (e.g., Nature Needs Half movement [40]). But our empirical approach provides sufficient arguments to conclude that conservation biology does not accumulate studies dedicated to strict nature protection with no or little connexion to human well-being. Rather, we show that several targets including the protection of nature for itself, nature for people, and nature with people are coexisting [8]. Interestingly, among most effective conservation actions, protected areas are still playing a major positive role. More generally, as the world becomes ever more dominated by humans, conservation of species in the wild is in fact even more relevant [41]. What we argue, however, is that proposing dramatic, top–down changes to a discipline, or accusing it of ‘failure’, not only appears counterproductive, but also ignores the dynamics of science itself. But more importantly, this debate is a classical diversion from the more profound causes of biodiversity loss. We thus concur with adopting more lucid approaches to existing and nonreducible conflicts between biodiversity conservation and the deny of any limits to destructive human activities. Calling for new directions to conservation is neither necessary nor sufficient. Constantly seeking even more compromise when nature protection is at stake is part of the major obstacles, not of the solutions (see Outstanding Questions).

Outstanding Questions The difficulty to address conservation challenges does not result from the conservation agenda itself. The new conservation debate should focus on what is working or not and why, rather than proposing new directions for the discipline. Recognizing the existence of several biases in the distribution of research studies among countries, taxonomic groups, or topics should motivate even higher conservation efforts. In the future, the success stories of conservation actions and the effectiveness of existing conservation tools should be better investigated.

Supplemental Information Supplemental information associated with this article can be found online at https://doi.org/10.1016/j.tree.2018.07.004.

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