Spatial and Temporal Variability in Subtidal Macroinvertebrates Diversity Patterns in a Management and Exploitation Area for Benthic Resources (Meabrs)
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Ocean & Coastal Management 93 (2014) 121e128 Contents lists available at ScienceDirect Ocean & Coastal Management journal homepage: www.elsevier.com/locate/ocecoaman Spatial and temporal variability in subtidal macroinvertebrates diversity patterns in a management and exploitation area for benthic resources (MEABRs) Pilar Molina a, F. Patricio Ojeda a, Marcela Aldana a,b,c, V.M. Pulgar d, * M. Roberto García-Huidobro c, José Pulgar b, a Pontificia Universidad Católica, Alameda 340, Santiago, Chile b Universidad Andres Bello, Departamento de Ecología & Biodiversidad, República 470, Santiago, Chile c Escuela de Pedagogía en Biología y Ciencias, Facultad de Ciencias de la Educación, Universidad Central de Chile, Santa Isabel 1278, Santiago, Chile d Center for Research in Obstetrics & Gynecology, Wake Forest School of Medicine and Biomedical Research Infrastructure Center, Winston-Salem State University, Winston-Salem, NC, USA article info abstract Article history: Diversity and biological variability are key attributes to maintain a viable life system in the marine Available online 12 April 2014 benthic zone and this balance is heavily affected by human activities. In Chile, Management and Exploitation Areas for Benthic Resources (MEABRs) are coastal areas administrated by local fishermen, which regulate the extraction of species of commercial of commercial importance (e.g. Concholepas concholepas, Fissurella spp. Loxechinus albus), key components of food webs. Both spatial and temporal impacts these species have on the structure and dynamics of the subtidal community are poorly un- derstood. In one of the oldest MEABRs of Chile we evaluated spatial and temporal effects of controlled extraction of commercial species on subtidal macro invertebrate’s diversity. Our results indicate that in a spatial scale MEABRs showed increased species richness, and important temporal changes in diversity and species composition from bivalves, ascidians and gastropods to cnidarians, sponges and bryozoans. We discuss possible mechanisms associated with the combined effects of fishery management and predation by key species on temporal composition variation in the subtidal macro invertebrate assem- blage in this regulated area. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction Botsford et al., 1997; Castilla, 1999, 2000; Dayton et al., 1995; Hockey and Bosman, 1986; Siegfried et al., 1985). Predation is one of the key processes governing structure of Marine Protected Areas (MPAs) have gained worldwide recog- natural communities (Duffy, 2002; Hairston et al., 1960). In recent nition as an important tool for biodiversity conservation and years, the threat of human activities as a top-down perturbation resource management (Allison et al., 1998; Fernández et al., 2000; that affects populations of large predators in natural ecosystems Lauck et al., 1998; Roberts, 1997), including protection of spawning has been fully recognized. Thus fishing has been demonstrated to stock, increase of recruitment rates, maintenance of the age and severely impact target species that in most cases are represented by size structures of stocks, and preservation of biodiversity. MPAs high trophic level predators (Fernández and Castilla, 2005; Jackson showed ability to protect habitats, conserve biodiversity and et al., 2001; Pauly et al., 1998; Myers and Worm, 2003; Sala et al., defend endangered stocks from overexploitation (Gell and Roberts, 1998; Steneck, 1998; Tegner and Dayton, 2000). The evidence in- 2003; Halpern and Warner, 2002; Halpern, 2003; Lubchenco et al., dicates that harvesting by humans can have dramatic effects on the 2003; Manríquez and Castilla, 2001; Shears and Babcock, 2003). structure and function of marine communities (Agardy, 1994; In this context, field evidence obtained from experimental ecological studies in Chile has been essential to demonstrate hu- man impacts on inshore coastal ecosystems (e.g. Castilla and Durán, 1985; Castilla and Bustamante, 1989; Castilla, 1999, 2000; Moreno * Corresponding author. Tel.: þ56 2 6618416. et al., 1984). In MPAs of southern Chile, an increase in the density E-mail address: [email protected] (V.M. Pulgar). of keyhole limpets (Fissurella spp.) was detected during the first five http://dx.doi.org/10.1016/j.ocecoaman.2014.03.005 0964-5691/Ó 2014 Elsevier Ltd. All rights reserved. 122 P. Molina et al. / Ocean & Coastal Management 93 (2014) 121e128 years as consequence of human gatherers exclusion. This change Table 1 was coupled with a decline in the abundance of mid-intertidal Results of General Linear Model (Two-Way ANOVA) comparing the time spent filming the different types of subtidal habitats (boulders, crevices, walls, algae, and macroalgae (Moreno et al., 1984). In central Chile, human exclu- sand) in MEABRs and open-access area (sampled sector). df ¼ degrees of freedom, sion resulted in higher density of muricid gastropod Concholepas MS ¼ mean square, F ¼ F value, p ¼ probability value. concholepas, which in turn resulted in stronger predation of the Effect df MS Fp dominant intertidal mussel Perumytilus purpuratus. Primary space liberated by predation was colonized by barnacles, such as Sampled sector (SS) 1 0.76 0.012 0.91 Notochthamalus scabrosus and Jehlius cirratus, and several species of Habitat (H) 4 400.02 6.57 0.0001 SSxH 4 152.65 2.50 0.041 macroalgae (Castilla, 1999; Navarrete et al., 2010). Error 506 60.83 Management and Exploitation Areas for Benthic Resource (MEABRs) represent a tool for management and diversity protec- tion developed in Chile (Castilla and Fernández, 1998; Gelcich et al., 2008; Manríquez and Castilla, 2001). The Chilean Under- comparisons were developed in the same sector, nearest to secretary of Fisheries assigns temporary permits quotes to legally CIMARQ (Center for Marine Investigation Quintay, Universidad registered artisanal fishing associations in defined geographical Andres Bello). In spatial evaluation, open-access area corresponds coastal areas, ranging from 50 to 300 ha of seabed. MEABRs are to a zone adjacent to MEABRs; and the temporal evaluation was created and assessed considering economically important benthic performed by comparing data obtained in 1989e1990 (just before species such as the carnivorous muricid gastropod Concholepas the establishment of MEABRs) under tenure of project FONDECYT concholepas (evaluated in w80% of MEABRs), key-hole limpets, 0349/1989 (F. P. Ojeda) with those obtained during 2008e2009 Fissurella spp. (w70%), and the red sea urchin Loxechinus albus (about 20 years after the establishment of MEABRs). In each of (w30%) (Castilla et al., 2007). The biological and economic suc- these areas, habitat characterization, density and richness of cesses of MEABRs policies have been proclaimed based on sub- macro-invertebrates were surveyed by SCUBA divers along subtidal stantial increases in abundances and sizes of managed species transects perpendicular to the coast. All diving activities were within MEABRs in comparison to open-access areas (Castilla and performed from a fisherman boat. Fernández, 1998; Castilla et al., 1998; Gelcich et al., 2008; Manríquez and Castilla, 2001; SUBPESCA, 2002). However, this 2.1. Habitat characterization economic success is associated to important dynamic and struc- tural changes in the marine ecosystem (Castilla, 2000; Gelcich Frequency of different habitats was estimated by filming for one et al., 2008), which would be even more relevant when the minute in 360 , every 10 m of depth in six subtidal transects within extent of MEABRs is considered. The 479 MEABRs in full operation of MEABRs and three subtidal transects in open-access area, at are spread over w1100km2 along the coast of Chile (SERNAPESCA, depths from 2 to 32 m. Habitat considered were: boulders, crevices, 2011), which exceeds the total area covered by no-take marine walls, algae, and sand. Data are expressed as habitat type by second. reserves, marine concessions with conservation purposes, multiple This methodology is a modification of nondestructive visual sam- use MPAs, and marine park (Fernández and Castilla, 2005). pling methods (Gelcich et al., 2008). MEABRs spread across the w4 000 km of coastal Chile and thus have the potential to scale-up the sustainable use of benthic re- 2.2. Spatial comparisons sources and also enhance marine conservation initiatives (Castilla, 2000; Castilla et al., 2007). The macro-invertebrates density and richness were recorded Despite MEABRs economic success, some objections have been along seven transects within of MEABRs and four transects in open- risen due to: a) the lack of baseline studies or information pre- access area, at depths from 2 to 30 m. They were set perpendicular vious to MEABRs started operation (Parnell et al., 2005; Sale et al., to the coast and were surveyed by autonomous divers. In each 2005), and specifically because b) only economically benthic transect and every 2 m, on average four quadrats (0.5 Â 0.5 m) were species are included in the biological evaluation. These are surveyed. The position of transect and quadrants were randomly fundamental and critical points to validate MEABRs as manage- allocated. ment and biological conservation tools and finally determine the ecological change associated to protection (Castilla, 2000; Folke et al., 2005; Huitric, 2005). The aim of our study was: a) to compare community structure in a MEABRs versus an open- access area (non protected marine belt, with free access to marine resources), and b) to evaluate temporal ecological varia- tions in community