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Weighing the benefits of expanding protected areas versus managing existing ones


Protected areas are a fundamental mechanism for conserving global biodiversity. Given limited conservation funds and shortfalls in funding for existing protected area management needs, a critical question is: should countries and states spend new funds on purchasing more land or managing existing protected areas to an acceptable standard? We used a non-spatial dynamic landscape model to compare the relative importance of expansion of protected areas versus improved protected area management in diverse contexts. We provide guidance on how to allocate funding across these two actions, and the order in which these actions should be prioritized. We discover that, in contrast with spending patterns, which focus on expansion rather than management, management is often the better first investment. The relative priority of expansion and management is determined by observable factors: the relative costs of the two actions and rates of degradation in protected and unprotected areas. Importantly, regardless of these factors, the final recommended action is always to split the budget across expansion and management such that there is adequate money for management. This highlights that, while our existing protected areas are an important asset, increased investment in management is essential to maximize their potential to protect biodiversity.

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Fig. 1: Flow chart of the six potential system states and the possible pathways between those states.
Fig. 2: An example of the optimum pattern of spending for managing a landscape transformer in the Succulent Karoo hotspot.
Fig. 3: Starting action (manage or expand) when considering landscape-transforming threats.
Fig. 4: Proportion of budget dedicated to management in the first year when managing selective pressures, assuming management and acquisition costs are equal (r = 1).

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All relevant data are within the paper and its Supplementary Information.

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The MATLAB code is available from the authors on request.


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V.M.A., G.D.I. and H.P.P. were funded by the Australian Research Council ( H.P.P. was funded by an Australian Research Council Laureate Fellowship.

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Authors and Affiliations



V.M.A., G.D.I. and H.P.P. developed the initial idea. V.M.A. designed and ran the simulations. V.M.A., G.D.I. and H.P.P. wrote the paper.

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Correspondence to Vanessa M. Adams.

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The authors declare no competing interests.

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Supplementary information

Supplementary Information

Supplementary methods, Supplementary Figs. 1–5, Supplementary Table 1, Supplementary references 1–6

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Adams, V.M., Iacona, G.D. & Possingham, H.P. Weighing the benefits of expanding protected areas versus managing existing ones. Nat Sustain 2, 404–411 (2019).

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