Shifted baselines 389
time of 35–50 years, and hawksbill 20–40 years. Therefore, with the exception of the turtle hatchery, it is unlikely that these conservation actions and policies could have resulted in population increases within this time frame. Likewise, parrotfish, lobster, grouper and conch were all considered to be increasing, but with legislation in place for less than one generation time for each group. Conservation policies include the implementation of closed seasons for these other taxa in 2013 (Barbuda Council, 2013). On Barbuda, parrotfish harvesting was banned and a system of extensive marine reserves was created in 2014 (Barbuda Council, 2014). Given that enforcement of these new regula- tions was implemented slowly on both islands, and the gen- eration times for parrotfish and groupers are 3 to.10 years, respectively, it is unlikely that any increases in abundance to date are the result of these policy changes.
Discussion
Local ecological knowledge, ecological data and historical observations
Our results reveal that, collectively, resource users on three Caribbean islands identify declines in key taxa, including coral, other invertebrates and reef fish. These perceptions are largely confirmed by ecological data. Barbuda has live coral cover as low as 2.6% (Jackson et al., 2014) and the de- cline in coral cover during 2005–2008 for the island was es- timated to have been 12.7% (Ruttenberg et al., 2013). Across both Antigua and Barbuda there have been documented de- clines in reef cover and health (Francis, 2010). In Montserrat the volcanic eruption and continued sedimentation de- stroyed large portions of reef off the southern and eastern coasts (Ferguson & Daniel, 2015), consistent with intervie- wees’ responses. Forty per cent of interviewees described grouper and parrotfish as declining; ecological assessments re- port low abundance of large fish species around Montserrat, Antigua and Barbuda (Francis, 2010; Ruttenberg et al., 2013;
Ferguson &Daniel, 2015). The decline in invertebrate popula- tions on the islands is also mirrored by interviewee percep- tions: .50% of interviewees described lobster as declining and 40% described conch as declining. Declines have oc- curred in landings of spiny lobster on Barbuda (Peacock, 1974; Albuquerque & McElroy, 1995) and conch popula- tions are low on Barbuda compared to other Caribbean islands (Ruttenberg et al., 2013). Despite this alignment of ecological assessments and in-
terviewees’ responses, we also identified a shifted baseline in the degree and extent of perceived change in the abundance of key taxa, with years of experience dictating perceptions of decline. Our approach of prioritizing knowledgeable indivi- duals may have underestimated this shifting baseline effect, as many fishers or divers may have less experience than our interviewees. At the same time, even our knowledgeable in- terviewees were limited in their observations to the past 2–3 decades. The species with the longest generation time and lowest possible recovery rates were not perceived to have declined, whereas the shorter-lived species were. This may be because many of these species were probably depleted before the period observed by any of our interviewees. Although historical information is limited, it suggests re- duction in abundances extending back decades or centuries. Historical sources from the 1790s to early 1900s describe abundant snapper, sharks and barracuda on Montserrat, Antigua and Barbuda (Riddell, 1792; Coleridge, 1826; Nutting, 1919; Supplementary Table 3) and early maps refer- ence locations named after particular taxa (Fig. 3), usually an indication that the taxa were abundant there.We located five maps published between 1748 and 1977 that referenced our taxa of interest, including sharks, groupers, snappers and lobsters. For example, a 1784 map noted ‘sharks without number’ west of Antigua and Barbuda, and a 1977 map in- dicated a location south of Barbuda as having ‘excellent spearfishing’ for groupers. These observations suggest that these marine species were historically abundant, and may have declined prior to observations by our interviewees. More recent historical information also indicates reef
FIG. 3 (a) The Caribbean, with rectangle indicating the location of the islands of Montserrat, Antigua and Barbuda, and (b) places named after marine species, identified from historical maps, with year of map (from: Baker, 1748;De La Rochette, 1784; Luffman, 1788; Fielding, 1824; Nicholson & Sons, 1977).
Oryx, 2020, 54(3), 383–391 © 2018 Fauna & Flora International doi:10.1017/S0030605318000169
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