Conclusions
This study adds strong evidence to a body of literature (Bennett & Arcese 2013; Tulloch et al. 2016; Hunter et al. 2017; Deane & He 2018; Wintle et al. 2019; Deane et al. 2020; Fahrig 2020; Valdés et al. 2020; Yan et al. 2021; Riva & Fahrig 2022) suggesting it is time to reconsider the widespread principle that large patches should always be prioritized in conservation. We suggest instead a new principle: For a given total area, protecting the largest possible number of patches, including very small ones, will maximize biodiversity for most taxa.This conclusion is grounded in a synthetic analysis of a large biodiversity dataset that includes information on both the taxonomic identities and relative size of small and large patches, two factors that have been so far poorly understood in the context of SLOSS meta-analyses (Deane et al. 2020; Fahrig 2020; Riva & Fahrig 2022).
We stress that consideration of patch sizes cannot compensate for loss of habitat. When the goal is to protect biodiversity, the priority should be to maximize the total area of habitat protected regardless of patch sizes. This also implies that continuous habitat should not be fragmented for biodiversity conservation, because this would entail habitat loss, the most important contributor to biodiversity declines (Caro et al. 2022). Furthermore, large habitat patches are now very rare in human-dominated regions (Taubert et al. 2018) and can fulfill specific roles (Arroyo-Rodríguez et al. 2020; Fahriget al. 2022). For instance, here we find that they are important for conservation of amphibians and reptiles.
That being said, the cumulative value of small patches for biodiversity has long been underappreciated. Recognizing this value will allow conservation agencies to capitalize on all opportunities for habitat protection, independent of patch sizes, facilitating habitat protection in regions where the only remaining patches left are small (Shafer 1995; Fahrig 2020; Riva & Fahrig 2022), and empowering individuals and communities to protect the nature that they experience in their daily lives (Fahrig 2019; Riva & Fahrig 2022). In a best-case scenario, acknowledging the benefits of small patches could trigger a new epoch of bottom-up conservation actions, driven by the efforts of communities and large numbers of local conservation initiatives.
Acknowledgments : FR acknowledges the support of a Mitacs Accelerate Fellowship.