Shifted baselines and the policy placebo effect in conservation


SAMANTHA LOVE L L,AYA N A E LIZABETH JOHNSON ROB IN RAMDEEN and LOREN MCCLENACHAN


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 ef- forts have resulted in localized recoveries of species and eco- systems. 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; stake- holders with more experience identifiedmore species as de- pleted 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 evi- dence 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 com- munities to set more ambitious conservation goals.


Keywords Historical ecology, local ecological knowledge, marine conservation, marine protected areas, policy pla- cebo, recovery, shifting baselines


Supplementary material for this article is available at https://doi.org/10.1017/S0030605318000169


Introduction I


nformation on long-term change is important for conser- vation andmanagement, particularly in coastal ecosystems,


SAMANTHA LOVELL* and LOREN McCLENACHAN (Corresponding author) Environmental Studies Program, Colby College, 5351 Mayflower Hill Drive, Waterville, Maine, USA. E-mail lemcclen@colby.edu


AYANA ELIZABETH JOHNSON, Ocean Collective, Brooklyn, New York, USA ROBIN RAMDEEN,Waitt Institute, Montserrat, West Indies *Also at: Environmental Defense Fund, Washington, DC, USA


whose history of degradation can be obscured by a lack of ecological data from the past (Jackson et al., 2001). Failure to document past change can lead to the shifting baseline syndrome, in which knowledge of past ecosystem produc- tivity is lost over the course of generations (Pauly, 1995). Shifted baselines have been documented among marine resource users; for example, in both Mexico and Brazil older fishers named more fish species and fishing sites as depleted than younger fishers (Sáenz-Arroyo et al., 2005; Giglio et al., 2015). In Curaçao and Bonaire (Netherlands), fishers’ baselines were not shifted because stories of plentiful past catches were passed down within these communities, whereas scuba divers had unrealis- tically positive perceptions of the health of the reefs and fish populations because they lacked this information (Johnson & Jackson, 2015). Such shifted baselines have im- plications for conservation, as they may lead to reduced restoration targets for exploited species (McClenachan et al., 2012, 2018). Change in Caribbean marine ecosystems has been docu-


mented over century-long time scales, with historical losses of large vertebrates fundamentally altering trophic dynamics (McClenachan et al., 2006; McClenachan & Cooper, 2008), losses of herbivorous fishes such as parrotfish (Scarus spp.) contributing to declines in reef accretion rates (Cramer et al., 2017), and reductions in the spatial distribution of coral reef habitats (McClenachan et al., 2017). In recent decades, the three-dimensional structure of Caribbean reefs has been re- duced (Alvarez-Filip et al., 2009), and hard coral cover de- clined on average by 50% between the 1970s and early 2000s, with shifts to non-framework building species (Jackson et al., 2014). Together with ongoing overfishing, these changes have led to declines in the density of both exploited and unexploited reef fishes (Paddack et al., 2009). A phase shift from coral to algal dominance was triggered and maintained by a combination of a disease in the sea urchin Diadema antillarum in the early 1980s, overexploitation of parrotfish and other algal grazers (Jackson et al., 2014), and land-based pollution (Cramer et al., 2012, 2015). More recently, climate change, disease, and invasive species have added additional stresses (Hoegh-Guldberg et al., 2007;Green et al., 2012;Randall &van Woesik, 2015). Despite these longer-term declines in Caribbean marine


Received 2 August 2017. Revision requested 20 October 2017. Accepted 18 January 2018. First published online 18 October 2018. Oryx, 2020, 54(3), 383–391 © 2018 Fauna & Flora International doi:10.1017/S0030605318000169


ecosystems, some recent conservation efforts have been suc- cessful, and localized recoveries of marine species and eco- systems are occurring. Although Caribbean green turtle


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