Implications of zero‐deforestation commitments: Forest quality and hunting pressure limit mammal persistence in fragmented tropical landscapes

Abstract

Zero-deforestation commitments seek to decouple agricultural production and forest loss to improve prospects for biodiversity. However, the effectiveness of methods designed to meet these commitments is poorly understood. In a highly fragmented tropical landscape dominated by oil palm, we tested the capacity for the High Carbon Stock (HCS) Approach to prioritize forest remnants that sustain mammal diversity. Patches afforded high priority by HCS protocols (100 ha core area) provided important refuges for IUCN-threatened species and megafauna. However, patch-scale HCS area recommendations conserved only 35% of the mammal community. At least 3,000 ha would be required to retain intact mammal assemblages, with nearly 10 times this area needed if hunting pressure was high. While current HCS protocols will safeguard patches capable of sustaining biodiversity, highly fragmented tropical landscapes typical of zero-deforestation pledges will require thinking beyond the patch toward strategically configured forest remnants at the landscape level and enforcing strict controls on hunting. K E Y W O R D Sbiodiversity, camera-trapping, habitat fragmentation, High Carbon Stock Approach, land-use planning, occupancy modeling, oil palm, RSPO, Southeast Asia, tropical forest INTRODUCTIONTropical forests are important reservoirs for biodiversity, but are compromised by anthropogenic activities (Barlow et al., 2018). Over 200 million ha of tropical forest has been lostThis 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.

Altered structure and stability of bat-prey interaction networks in logged tropical forests revealed by metabarcoding

“…Systems that are specialised in this manner have been shown to be more vulnerable to extinctions than those with a more generalised structure (Memmott et al, 2004), such as the old growth rainforest networks analysed. Rainforests in Southeast Asia are facing multiple stressors, including the effects of disturbance, habitat fragmentation and climate change (Deere et al, 2020; Struebig et al, 2015). Our findings of altered network structure in an area which has been selectively logged indicate that such logged forests may be more sensitive to the effects of these future perturbations.…”

The environmental impacts of palm oil in context

“…Oil palm in Guatemala and Brazil supported 23 and 58 bird species, respectively 36,38 , while 12 species of snakes were found in a Nigerian oil palm plantation 39 . Various species will enter plantations to feed on oil palm fruit, including palm-nut vultures Gypohierax angolensis 43 and chimpanzee Pan troglodytes 40 in Africa and porcupines (Hystricidae), civets (Viverridae), macaques (Cercopithecidae), elephants (Elephantidae) and orangutans in Southeast Asia 41 . The highest diversity of animal species in oil palm areas, however, is generally found in the wider landscape that includes remnant patches of native vegetation 42,43 .…”

“…Various species will enter plantations to feed on oil palm fruit, including palm-nut vultures Gypohierax angolensis 43 and chimpanzee Pan troglodytes 40 in Africa and porcupines (Hystricidae), civets (Viverridae), macaques (Cercopithecidae), elephants (Elephantidae) and orangutans in Southeast Asia 41 . The highest diversity of animal species in oil palm areas, however, is generally found in the wider landscape that includes remnant patches of native vegetation 42,43 . Factors that are likely to positively influence biodiversity values in both industrial-scale and smallholder plantations include higher landscape heterogeneity, the presence of large forest patches and connectivity among these 44 , and the plant diversity and structure of undergrowth vegetation.…”

Designing optimal human‐modified landscapes for forest biodiversity conservation

“…2010); (5) maintaining a small number of large forest patches (Diamond 1975); (6) maintaining a large number of small forest patches (Simberloff & Abele 1982; Fahrig 2017, 2020) and (7) improving the quality of the anthropogenic matrix by reducing agricultural intensification (Hendershot et al . 2020), pesticide use (Sánchez‐Bayo & Wyckhuys 2019) and hunting (Deere et al 2020), and implementing measures to mitigate wildlife road‐kill (Rytwinski & Fahrig 2015; Alamgir et al . 2017).…”