Welcome small patches; beware of the risks of changing conservation priorities

Abstract

Welcome small patches; beware of the risks of changing conservation prioritiesRecently, Riva and Fahrig revisited the SLOSS question with fresh data from Chase et al. (2019) and concluded that small patches (SP) are disproportionately important for biodiversity conservation compared to large patches (LP). They recommended that conservation priorities, canonically oriented toward LP, should shift to recognize the value of SP. We appreciate their new analysis, agree that SP have outstanding importance for maintaining diversity, and understand they do not suggest neglecting LP. However, we want to clarify two points. First, the political reality is that conservation decisions are rarely as clean cut as choosing to conserve one large patch versus several SP. Second, time lags and spatial dependencies in extinction dynamics severely complicate the interpretation that SP are better for biodiversity conservation.Conservation biology does not happen in a void, and studies that seek to influence decision-making need to address political and institutional reality. Many countries, especially in the tropics, face recurring threats to biodiversity, including inside protected areas, and these threats are not distributed evenly across patch sizes, occurring more severely on SP (e.g., Reid et al., 2019). Even large reserves with highly restrictive human use face multiple threats including deforestation, changes in protection status, and/or area reduction. Moreover, the dismantling of environmental laws and institutions in charge of environment protection, currently happening in several countries (e.g., Vale et al., 2021), put at risk the role current reserves of any size have in protecting highly sensitive species and those that require large habitats.Furthermore, the detection of high species richness and globally endangered species in SP, even the older ones, does not guarantee the local presence of viable populations. These patterns may result from past landscape connectivity, especially in highly dynamic landscapes (e.g., Atlantic Forest). Although fragmented for decades, landscapes may have only recently crossed extinction thresholds (Figure S2), sheltering declining populations andThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.