Preserving 40% forest cover is a valuable and well‐supported conservation guideline: reply to Banks‐Leite et al

Abstract

Banks‐Leite et al. (2021) claim that our suggestion of preserving ≥ 40% forest cover lacks evidence and can be problematic. We find these claims unfounded, and discuss why conservation planning urgently requires valuable, well‐supported and feasible general guidelines like the 40% criterion. Using region‐specific thresholds worldwide is unfeasible and potentially harmful.

Maintenance of different life stages of old‐growth forest trees in deforested tropical landscapes

“…Such a decrease was particularly abrupt (i.e., nonlinear) in sites surrounded by <47% forest cover, suggesting that there could be an extinction threshold for adult trees in this region. This threshold value is within the range documented in other tropical forests (reviewed in Arroyo‐Rodríguez et al, 2020, 2021) and might be related to negative edge effects, as (1) we focused on well‐known edge‐sensitive tree species (i.e., old‐growth forest species; Santos et al, 2008; Tabarelli et al, 2012) and (2) edge effects are usually stronger in landscapes dominated by high‐contrast open‐area matrices (reviewed by Arroyo‐Rodríguez, Saldaña‐Vázquez, et al, 2017; Tuff et al, 2016), such as the cattle pastures that dominate the Los Tuxtlas region. In fact, although we avoided patch edges during sampling, sample sites in more deforested landscapes were unavoidably closer to forest edges, and the number of very small and edge‐affected patches is typically higher in landscapes with <40% of forest cover (see fig.…”

“…Our findings do not imply, however, that forest loss does not have negative effects on a landscape's biodiversity. As deforestation proceeds, the number of forest‐specialist individuals and species in the whole landscape logically decreases, especially in landscapes with <40% of forest cover (Arroyo‐Rodríguez et al, 2021; Brindis‐Badillo et al, 2022; Wies et al, 2021). Therefore, preventing deforestation in all landscapes, including those where little or no deforestation has yet occurred, should be a top priority (Arroyo‐Rodríguez et al, 2020).…”

“…First, such biological responses are not always linear (proportional) because the local extinction of some species can accelerate in landscapes that have reached a certain deforestation boundary (i.e., the so‐called “extinction thresholds”; Lande, 1987). Extinction thresholds are usually evident in landscapes with 10%–30% of remaining forest cover (reviewed by Swift & Hannon, 2010), although higher thresholds (30%–50%) have also been documented in the tropics (Arroyo‐Rodríguez et al, 2020, 2021). This implies that nonlinear statistical models may fit the data better than linear models (Brindis‐Badillo et al, 2022; Morante‐Filho et al, 2015), so both linear and nonlinear models need to be considered to make confident inferences on the impact of forest loss on biodiversity.…”

Increasing Forest Cover and Connectivity Both Inside and Outside of Protected Areas in Southwestern Costa Rica

“…The region likely has sufficient forest cover to effectively provide habitat to conserve a wide array of biodiversity. Across the tropics, studies have suggested regional forest cover threshold values of ~30-40% for the effective biodiversity conservation of most generalist species [58]. In some ecosystems, such as the Amazon, values of up to 85% are suggested [3]; Osa's forest cover meets both of these thresholds.…”

Spatial Ecology of Reddish-Brown Cuxiú Monkeys (Chiropotes sagulatus, Pitheciidae) in an Isolated Forest Remnant: Movement Patterns and Edge Effects

“…Understanding the extent to which the animals remain in isolated forest remnants, versus traveling in and out of forest remnants, is important for understanding how a species will use (or not use) a particular landscape. Such information could be an important consideration as people determine the best way to design landscapes for conservation [94][95][96].…”