The continuing decline and loss of global biodiversity has resulted in a wide range of policy initiatives and practical actions. One of the most publicly visible actions is protection for sites on land and, more recently, in the seas. Thankfully, as a result, protected areas such as Kinabalu, Serengeti and Yosemite all remain jaw-dropping natural spectacles. Beyond these well-known efforts, conservationists have been busy in other ways, and our armamentarium has expanded to include a wide diversity of approaches, including regulation, education, captive breeding, reintroduction, and habitat and species management.

But despite these extensive efforts, and the numerous successes, the global pattern remains gloomy. For example, the latest Living Planet Index (summarizing 16,704 population trends of 4,005 species) reported a 60% decline between 1970 and 2014 (WWF, Reference Grooten and Almond2018) and the recent Global Assessment of the Intergovernmental Panel on Biodiversity and Ecosystem Services (IPBES, 2019) noted that we are failing to halt the acceleration of extinctions.

One of our key tools is a multilateral treaty, the Convention on Biological Diversity, the objectives of which ‘are the conservation of biological diversity, the sustainable use of its components and the fair and equitable sharing of the benefits arising out of the utilization of genetic resources’. In 2020 representatives of most governments will meet at the Conference of the Parties to the treaty to adopt a new global biodiversity framework. As the 2020 deadline approaches there is increasing urgency to devise a range of possible options in preparation for that plan. The best known is E.O. Wilson's (Reference Wilson2016) vision that half of the Earth should be dedicated to nature (but see Büscher et al., Reference Büscher, Fletcher, Brockington, Sandbrook, Adams and Campbell2017a,Reference Büscher, Fletcher, Brockington, Sandbrook, Adams and Campbellb and Cafaro et al., Reference Cafaro, Butler, Crist, Cryer, Dinerstein and Kopnina2017). Here I suggest another: kaizen conservation.

There are innumerable examples of effective conservation measures, but alongside these successes there are many studies showing how not all conservation responses or interventions are fully effective. There is a problem of ignoring existing evidence, referred to as evidence complacency, with ineffective techniques being repeatedly used (Sutherland & Wordley, Reference Sutherland and Wordley2017). For example, despite the European Union spending many billion Euros annually on agri-environment schemes, numerous studies have shown that the results are mixed, with many adopted interventions being ineffective. Batáry et al. (Reference Batáry, Dicks, Kleijn and Sutherland2015) found no evidence of recent schemes being more effective than older ones, contrary to the expectation of continual improvement from learning by experience.

Collation of the evidence shows that methods really matter. For example, in creating under-road tunnels for amphibians, to avoid them being squashed by traffic, the diameter, length, whether lit, substrate used, whether water is present, entrance position, material and tunnel microclimate all influence their effectiveness (Smith & Sutherland, Reference Smith and Sutherland2014). This knowledge provides a great opportunity to learn and improve but there is neverthless not a culture of learning from past successes and failures.

The means by which conservation is implemented has also been shown to matter. In a review of marine protected areas, Gill et al. (Reference Gill, Mascia, Ahmadia, Glew, Lester and Barnes2017) showed that the response of fish populations (measured as biomass) to protection varied greatly. The best predictor of benefit was staff and budget capacity: protected areas with adequate staff capacity had fish biomass responses 2.9 times greater than areas with inadequate capacity. Similarly, Coad et al. (Reference Coad, Watson, Geldmann, Burgess, Leverington and Hockings2019) showed that less than a quarter of the terrestrial protected areas they examined had adequate staff and financial resources for effective protection.

I suggest we can learn from the Japanese practice of kaizen—change (kai) to become good (zen)—in which there is a collective commitment to identifying and delivering improvement (Carnerud et al., Reference Carnerud, Jaca and Bäckström2018). In a very different field, this approach has been considered as key to delivering much of Toyota's considerable success, and is widely imitated. We could adopt an approach of kaizen conservation with the objective of similarly seeking means of achieving good practice. A comparable approach was adopted by the British cycling team, who were committed to the ideal of ‘aggregating the marginal gains’ or, expressed more clearly, seeking ‘the 1% margin for improvement in everything you do’ in which they examined each component and considered how it could be improved (Harrell, Reference Harrell2015), whether adjusting tyre weight or improving hand washing to reduce infection risk. The improved performance was seen as central to the team's remarkable success. This concept of continual improvement is being applied more widely, such as in medical practice (Pentecost et al., Reference Pentecost, Richards and Frost2017).

The justification underpinning this proposal for kaizen conservation is that there is currently both excellent and weak practice. As in the examples above, weak practice can result from using ineffective measures or from poor implementation as a result of insufficient staff, equipment, resources, experience, knowledge or commitment. Concentrating on improving practice is likely to be highly cost effective, with the core idea being to focus on improved delivery, including building on the global experience of successes and failures through the large-scale delivery of evidence-based conservation (Sutherland & Wordley, Reference Sutherland and Wordley2017).

What would an agenda for kaizen conservation look like? There is need to strengthen a range of elements, in particular by: (1) ensuring there are sufficient staff, (2) enhancing training to increase capacity and skills, both in programme management and in delivery, (3) continuing the collation of existing knowledge on the effectiveness of interventions, (4) disseminating recommendations for best practice effectively, (5) ensuring suitable equipment is available, including the appropriate use of modern technologies, and (6) greater testing of options, with feedback to the global community.

There are a range of plans and proposals for responding to the 2020 meeting of the Conference of the Parties to the Convention on Biological Diversity but as these typically act at a higher level they are compatible with kaizen conservation. For example, the idea of ‘bending the curve’ (Mace et al., Reference Mace, Barrett, Burgess, Cornell, Freeman, Grooten and Purvis2018) is that recovery is feasible using existing targets and commitments. One of the key three steps in bending the curve is ‘to identify actions to deliver the required biodiversity improvements. Traditional biodiversity conservation interventions such as protected areas and species conservation planning remain crucial, but actions must also address major drivers of biodiversity loss and ecosystem change’. Kaizen conservation is a means to deliver this critical step. Similarly, ambitions for dedicating more land to nature (including Half-Earth) or large-scale restoration (e.g. Wolff et al., Reference Wolff, Schrammeijer, Schulp and Verburg2018) are dependent upon effective delivery. Visconti et al. (Reference Visconti, Butchart, Brooks, Langhammer, Marnewick and Vergara2019) suggested a novel target ‘The value of all sites of global significance for biodiversity, including key biodiversity areas, is documented, retained and restored through protected areas and other effective area-based conservation measures’. This is also based on recognizing the mixed effectiveness of current actions and the need to deliver biodiversity conservation rather than to confine actions to paper.

I am not suggesting that kaizen conservation could be the sole or even major means to halt the continuing decline and loss of global biodiversity; it has to act of course alongside other measures, including expansion of the area protected and improvements in other tools. However, it seems likely that the improved delivery of conservation through kaizen conservation could not only be a cost effective means of benefiting wildlife, but that demonstrating increased cost-effectiveness could also lead to greater respect from society and so make further funding of conservation seem more justifiable and attractive.