Shifted baselines and the policy placebo effect in conservation

Abstract

Coastal ecosystems have been degraded by human activity over centuries, with loss of memory about past states resulting in shifted baselines. More recently conservation efforts have resulted in localized recoveries of species and ecosystems. Given the dynamism of ecosystem degradation and recovery, understanding how communities perceive long-term and recent changes is important for developing and implementing conservation measures. We interviewed stakeholders on three Caribbean islands and identified a shifted baseline with respect to the extent and degree of long-term declines in marine animal populations; stakeholders with more experience identified more species as depleted and key species as less abundant than those with less experience. Notably, the average respondent with < 15 years of experience listed no species as depleted despite clear evidence of declines. We also identified a phenomenon we call the policy placebo effect, in which interviewees perceived some animal populations as recently recovering following passage of new conservation legislation but in the absence of evidence for actual recovery. Although shifted baselines have a negative effect on conservation as they can lower recovery goals, the outcomes of a policy placebo effect are unclear. If the public prematurely perceives recovery, motivation for continued conservation could decline. Alternatively, perception of rapid success could lead communities to set more ambitious conservation goals.

Forgotten whales, fading codfish: Perceptions of ‘natural’ ecosystems inform visions of future recovery

“…The early decline and lack of subsequent recovery for right whales means that these inshore populations have been forgotten, which has implications for the ongoing controversy around the recovery and conservation of this species. This loss of ecological memory through time, or shifting ecological baseline, is similar to those reported from marine systems around the world (e.g., Lovell et al, 2020; Saenz‐Arroyo et al, 2005).…”

“…Perceptions of ecological baselines affect views of current ecosystem state (Pauly, 1995). Stakeholders with a long‐term understanding of ecological change perceive more depletion relative to past baselines, with implications for fisheries (Lovell et al, 2020; Saenz‐Arroyo et al, 2005), nonnative species management (Clavero, 2014), and species extinction (Turvey et al, 2010). Shifted baselines also directly inform future management.…”

Telling the same story: Fishers and landing data reveal changes in fisheries on the Southeastern Brazilian Coast

“…The small number of species reported by less experienced fishers compared with experienced ones may reflect the lack of familiarity and/or a reduced interaction of fishers with the natural environment [49]. Such disconnection with past conditions has effects on the willingness and motivation of new generations to accept management restrictions aimed to restore resources and even mislead recovery perceptions, the "placebo effect" [87]. In Arraial do Cabo, the overexploitation of fishing resources [21,54] has made less experienced fishers look for alternative income sources.…”

Fishing historical sources: a snapshot of 19th-century freshwater fauna in Spain

“…the Living Planet Index uses data starting in 1970). The underestimation of biodiversity losses can mislead the definition of conservation baselines and the conservation targets derived from them (Clavero et al 2022a), potentially generating a shifting baseline syndrome (Lovell et al 2020).…”