Adversarial procurement in two-value space: insights and evidence for conservation siting

More than 190 countries have committed to protecting 30% of the Earth’s land and oceans by 2030 — the ‘30×30’ goal agreed under the 2022 Kunming–Montreal Global Biodiversity Framework. At present, about 18% of land and 10% of oceans are formally protected. Reaching the target will therefore require a near doubling of protected land and a near tripling of protected marine areas, implying a much faster pace of conservation than seen to date. This raises a key question: where should these new protected areas be located?

Conservation planning often begins with a fixed map based on the ecological value, development threat and acquisition cost of the land being considered. Based on this setup, two common strategies emerge: (i) target sites that give the greatest conservation benefit for the lowest cost to maximise efficiency; and (ii) target sites that are most at risk of development to make the most difference, i.e. to achieve ‘measured additionality’. This paper shows that both strategies can fail in an adversarial setting — which the authors call adversarial procurement in two-value space — where a mission-driven buyer (the conservationist) acquires land parcels sequentially from a shared pool against an active rival (the developer) with land prices set by the developer’s valuation. In this setting, price is both a cost and a signal of development threat; developers move their attention to different sites and the available conservation options evolve in response to these interactions.

This paper develops a framework to analyse this type of competition and applies it to a case study in Bolivia. The findings suggest that commonly used rules for procuring conservation sites can perform poorly under these conditions. For example, prioritising sites that are most at risk of development does not consistently lead to better outcomes once competitors can respond strategically. Similarly, limiting a rival’s ability to shift its focus to other sites can unintentionally worsen overall outcomes. The analysis also shows that the widely used benefit–cost ratio approach can be outperformed by a simpler rule that ignores costs altogether.

Key points for decision-makers

• While conservation provides a clear example of this type of problem, it is not unique. Similar dynamics arise whenever a mission‑driven buyer operates with a fixed budget while competing against an active rival whose willingness to pay helps set prices. This includes areas such as healthcare purchasing, government procurement and public land acquisition.
• Two central lessons emerge from the research; first, competition changes how we should think about ‘threat’; and second, this two-value setting changes how we should interpret ‘cost’.
• These insights depend on two important conditions. They are strongest where buyers and rivals tend to value the same assets similarly (positive correlation, i.e. both place a high or low value on the same sites), and where there is enough variation in how different actors value those assets (valuation heterogeneity, i.e. not all sites are valued in the same way by everyone).
• For conservation practitioners, the implication is not to apply any single rule mechanically, but to recognise how competition reshapes the decision environment. In this context, a low price may signal low competition rather than good value, and sites with high estimated ‘additionality’ — the difference between conservation outcomes achieved with and without the intervention — may in fact be highly contested and therefore less secure.
• Overall, the findings point to a more robust approach to decision-making: start by identifying sites with the highest ecological value, and then use information on cost and threat to refine priorities — rather than allowing these factors to determine choices on their own.