Synergy claim (non-additivity): The authors define βsynergistic processesβ as positive/multiplicative interactions among threats that can produce biodiversity loss exceeding the sum of individual effects, with extinction probability becoming non-negligible when combined effects drive populations below MVP thresholds.
Empirical anchoring: The review cites examples including interactive habitat loss + fragmentation facilitating invasions/fire and case-based extinction cascades, plus a quantitative projection that continued deforestation could consign up to 79% of Southeast Asian vertebrates to extirpation by 2100 (with lagged βextinction debtβ shaping timing).
Key inference: Because the βdecouplingβ between the initial cause of decline and eventual extinction is central to the reviewβs mechanism, single-driver management could be insufficient if it fails to prevent the interacting pathways that corrode population viability and enable cascades.
What would most disconfirm this paperβs core thesis? Evidence that, across taxa/ecosystems, interacting drivers generally produce outcomes close to additive expectations once demographic stochasticity and population structure are accounted for, and that extinction timing/risk is not more sensitive to combined pressures than to single pressures.
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