Italian Marine Reserve Effectiveness: Does Enforcement Matter?
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BIOLOGICAL CONSERVATION 141 (2008) 699– 709 available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/biocon Italian marine reserve effectiveness: Does enforcement matter? Paolo Guidettia,*, Marco Milazzob, Simona Bussottia, Andrea Molinaric, Matteo Murenud, Antonio Paise, Nunziacarla Spano` f, Raffaella Balzanog, Tundi Agardyh, Ferdinando Boeroa, Giancarlo Carradai, Riccardo Cattaneo-Viettij, Angelo Caud, Renato Chemellob, Silvestro Grecoc, Antonio Manganarof, Giuseppe Notarbartolo di Sciarak, Giovanni Fulvio Russog, Leonardo Tunesic aDepartment of Biological and Environmental Sciences and Technologies, University of Salento, Via Provinciale Monteroni, 73100 Lecce, Italy bDepartment of Ecology, University of Palermo, Via Archirafi 18, 90123 Palermo, Italy cCentral Institute for Research on the Marine Environment, Via Casalotti 300, 00166 Rome, Italy dDepartment of Animal Biology and Ecology, University of Cagliari, Viale Poetto 1, 09126 Cagliari, Italy eDepartment of Animal Sciences, University of Sassari, Via De Nicola 9, 07100 Sassari, Italy fDepartment of Animal Biology and Marine Ecology, University of Messina, Salita Sperone 31, 98166 Messina, Italy gDepartment of Sciences for the Environment, University of Naples ‘Parthenope’, Via A. De Gasperi 5, 80133 Naples, Italy hSound Seas, 6620 Broad Street, Bethesda, MD 20816, USA iDepartment of Zoology, University of Naples ‘Federico II’, Corso Umberto I, 80138, Naples, Italy jDepartment of the Study of the Territory and its Resources, University of Genoa, Corso Europa 26, 16132 Genoa, Italy kTethys Research Institute, Viale G.B. Gadio 2, 20121 Milan, Italy ARTICLE INFO ABSTRACT Article history: Marine protected areas (MPAs) have become popular tools worldwide for ecosystem conser- Received 4 June 2007 vation and fishery management. Fish assemblages can benefit from protection provided by Received in revised form MPAs, especially those that include fully no-take reserves. Fish response to protection can 17 December 2007 thus be used to evaluate the effectiveness of marine reserves. Most target fish are high- Accepted 20 December 2007 level predators and their overfishing may affect entire communities through trophic cas- Available online 13 February 2008 cades. In the Mediterranean rocky sublittoral, marine reserves may allow fish predators of sea urchins to recover and thus whole communities to be restored from coralline barrens Keywords: to macroalgae. Such direct and indirect reserve effects, however, are likely to be related to Marine reserves the enforcement implemented. In Italy, many MPAs that include no-take reserves have Fish assemblages been declared, but little effort has been spent to enforce them. This is a worldwide phe- Conservation nomenon (although more common in some regions than others) that may cause MPAs Enforcement and reserves to fail to meet their targets. We found that 3 of 15 Italian marine reserves Mediterranean Sea investigated had adequate enforcement, and that patterns of recovery of target fish were related to enforcement. No responses were detected when all reserves were analyzed as a whole, suggesting enforcement as an important factor to be considered in future studies * Corresponding author: Tel.: +39 0832 298935; fax: +39 0832 298626. E-mail addresses: [email protected] (P. Guidetti), [email protected] (M. Milazzo), [email protected] (S. Bussotti), [email protected] (A. Molinari), [email protected] (M. Murenu), [email protected] (A. Pais), [email protected] (N. Spano` ), [email protected] (R. Balzano), [email protected] (T. Agardy), [email protected] (F. Boero), [email protected] (G. Carrada), [email protected] (R. Cattaneo-Vietti), [email protected] (A. Cau), [email protected] (R. Chemello), [email protected] (S. Greco), [email protected] (A. Manganaro), [email protected] (G. Notarbartolo di Sciara), [email protected] (G.F. Russo), [email protected] (L. Tunesi). 0006-3207/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.biocon.2007.12.013 700 BIOLOGICAL CONSERVATION 141 (2008) 699– 709 particularly to avoid that positive ecological responses in properly managed reserves can be masked by neutral/negative results in paper parks. Positive responses were observed for large piscivores (e.g. dusky groupers) and sea urchin predators at reserves where enforce- ment was effective. Those reserves with low or null enforcement did not differ from fished areas. Ó 2007 Elsevier Ltd. All rights reserved. 1. Introduction reserves are pooled to extract general patterns (e.g. in meta-analyses). Pooling data from enforced reserves and Generally speaking, marine protected areas (MPAs) refer to from paper parks carries the risk of incorrectly downplay- portions of the coastline and/or sea where human activities, ing the importance of reserves because neutral results from especially fishing, are restricted or banned (Agardy et al., paper parks could mask the positive responses of well-en- 2003). As fish assemblages usually include many species tar- forced reserves. geted by fishing, they are primarily expected to benefit from In the Mediterranean Sea there has been a rush in recent protection within MPAs, especially those having no-take re- years to establish MPAs and reserves (Juanes, 2001). In Italy serves (Dayton et al., 1995; Micheli et al., 2004; McClanahan there are currently 25 MPAs formally established (with more et al., 2007). The evaluation of these benefits, in terms of in- than 20 in the process of becoming established), ranging in crease in density and size of target fishes (Mosquera et al., size from 120 to more than 50,000 hectares in total surface 2000; Coˆte´ et al., 2001; Halpern, 2003; Micheli et al., 2004; Clau- area. Italian MPAs include one or more no-take/no-access det et al., 2006; Guidetti and Sala, 2007), can be useful to as- zones (hereafter called ‘reserves’ in the text and formally de- sess the ecological effectiveness of reserves. Moreover, most fined as ‘A zones’ according to Italian law), surrounded by buf- target fishes are high-level predators and their functional fer zones (defined as ‘B and C zones’, where restrictions to extinction may cause community-wide changes (Sala et al., human uses, including fishing, become progressively more 1998; Jackson et al., 2001). Protection from fishing, therefore, lax) (Villa et al., 2002). may directly restore populations of target fishes and indi- Previous studies that investigated fish response to protec- rectly drive whole communities towards an unfished state tion within Italian marine reserves showed (1) positive effects (Sala et al., 1998; Shears and Babcock, 2002; Micheli et al., (Vacchi et al., 1998; Guidetti et al., 2005; Guidetti, 2006) or neu- 2004; Bevilacqua et al., 2006; Guidetti, 2006). We use hereafter tral results (Tunesi et al., 2006) on fish density and size, and (2) the term ‘ecological effectiveness’ of marine reserves to de- no obvious patterns in terms of community shifts (Sala et al., fine the responses to protection from fishing encompassing 1998; Guidetti et al., 2005; Micheli et al., 2005; Guidetti, 2006; direct and indirect effects. Guidetti and Sala, 2007). As regards the community shift, Marine reserve studies have undoubtedly improved our two target sea breams, i.e. Diplodus sargus and Diplodus vulga- understanding of the unfished state of ecosystems and target ris, have been identified as the most effective predators of sea populations (Shears and Babcock, 2002; Guidetti and Sala, urchins, with the latter being the most important grazer in 2007). It is common wisdom, however, that a number of re- rocky reefs (Sala et al., 1998). When released from predation serves do not meet their potential ecological objectives and control, sea urchins may increase in density and overfeed that negative/neutral results in reserve studies are mostly on macroalgae, which in turn may cause the transition from underreported in the literature (Halpern and Warner, 2002). macroalgal beds to barrens (Sala et al., 1998). Since the recov- Failing reserves are attributable to causes like inappropriate ery of sea breams (and other predator fish) was observed design (Sala et al., 2002) or ineffective enforcement (Mora within reserves, along with lower urchin density and less et al., 2006), which may be overlooked if negative/neutral re- extended barrens (Guidetti and Sala, 2007), Diplodus density sults are not taken into account. can be assumed to be an index of the potential of reserves It is becoming increasingly recognized that a large pro- to recover from barrens to algal beds or to maintain flourish- portion of marine reserves around the world receive inef- ing algal beds. fective enforcement. These are the so-called ‘paper parks’, In spite of the increasing number of MPAs in Italy, no where protection occurs only in theory (Mora et al., 2006). general evaluations have been done to assess the ecological In such cases the use of proper sampling designs suggested responses to protection from fishing. A nation-wide project, by many authors to properly investigate reserve effective- named ‘‘Sistema Afrodite’’, was thus started in 2002 (Greco ness (CIESM, 1999; Guidetti, 2002), e.g. by comparing et al., 2004), with the aim of allowing a balanced assessment replicated ‘reserve vs fished’ sites, is useless. In fact, the of the actual effectiveness of marine reserves in the country comparison ‘reserve vs fished’ sites makes sense only if (including potential neutral/negative results). protection really occurs. The scant information