Government conservation policies on Mexican coastal areas: is ?top-down? management working?

Abstract

Marine and terrestrial ecosystems are declining globally due to environmental degradation and poorly planned resource use. Traditionally, local government agencies have been responsible of the management of natural reserves to preserve biodiversity. Nonetheless, much of these approaches have failed, suggesting the development of more integrative strategies. In order to discuss the importance of a holistic approach in conservation initiatives, coastal and underwater landscape value and biological/environmental indicators of coral reef degradation were assessed using the study case of Zihuatanejo, Guerrero coastal area. This area shelters representative coral reef structures of the Eastern Pacific coast and its terrestrial biodiversity and archaeology enhance the high value of its coastal area. This study explored the landscape value of both terrestrial and marine ecosystems using the geomorphosite approach in two sites on the Zihuatanejo coastal area: Caleta de Chon and Manzanillo Beach. Sedimentation rate, water transparency, chlorophyll and total suspended solids were recorded underwater in each site for environmental characterization. 50 photo-quadrants on five transects were surveyed between 3-4m depth to record coverage (%) of living corals, dead corals, algae, sand and rocks. The conservation status of coral reefs was assessed by the coral mortality index (MI). Landscape values showed that both terrestrial and marine ecosystems had important scientific and aesthetic values, being Manzanillo Beach the site with the highest potential for conservation initiatives (Ttv=14.2). However, coral reefs face elevated sedimentation rates (up to 1.16kg/m 2 d) and low water transparency (less of 5m) generated by coastal land use changes that have increased soil erosion in the adjacent coastal area. High coverage of dead corals (23.6%) and algae (up to 29%) confirm the low values in conservation status of coral reefs (MI=0.5), reflecting a poorly-planned management. Current conditions are the result of "top-down" conservation strategies in Zihuatanejo, as Federal and Municipal authorities do not coordinate, disregard local community in coral reef management, and ignore the intimate relationship between the coastal and marine realms. This work confirms the importance of conservation strategies with a holistic approach, considering both terrestrial and marine ecosystems in coastal areas; and that these initiatives should include local coastal communities in management and decision-taking processes done by government authorities. Rev. Biol. Trop. 59 (4): 1487-1501. Epub 2011 December 01.

Structure and temporal dynamic of tropical turf forming macroalgal assemblages of the western coast of Mexico

“…Zihuatanejo Bay has been subjected to a large deforestation between 2005 and 2007 that may lead to an increase in terrigenous sediments. For instance, a site 0.8 km SE from Las Gatas recorded a sedimentation rate of 1.2 kg m -2 day -1 (Nava & Ramírez-Herrera, 2011). The total and fine sedimentation high rates recorded in Puerto Mio Internal may be due to the bay hydrodynamics generated by the tides.…”

“…One consequence has been the rapid rise of sediment into the sea due to deforestation, drain downloads, and changes in land use affecting the structure and dynamics of benthic communities (Ferretti et al, 1989;Gorgula & Connell, 2004;Venturini et al, 2004;Florez-Leiva et al, 2009;Nava & Ramírez-Herrera, 2011).…”

“…Worldwide studies have shown that sedimentation plays a crucial role in the structure and dynamics of the algal assemblages (Piazzi & Cinelli, 2001;Miller et al, 2002;Eriksson & Johansson, 2005;Balata et al, 2007;Florez-Leiva et al, 2009;Shepherd et al, 2009). However in the Mexican tropical Pacific, the scarce studies carried out on sedimentation has been addressed to assess its effect on sponges communities (Carballo, 2006), on stony corals (Granja-Fernández & López-Pérez, 2008) and as an indicator of coral reef degradation (Nava & Ramírez-Herrera, 2011, nevertheless its relationship with macroalgal communities is unknown.…”

When good intentions are not enough … Insights on networks of “paper park” marine protected areas

“…Stakeholder participation in management may be low or restricted to a few individuals, for example in BLABR (Ramirez-Sanchez 2007) and LBNP (Peterson 2010). This may be because of the top-down management approach, which can result in a disconnect between stakeholders and managers (Nava & Ramírez-Herrera 2011). In UGCBR, conflict between small-scale fishers, indigenous groups, and authorities over dwindling fisheries stocks and the endangered vaquita has undermined management and conservation efforts (Ezcurra et al 2009;Bobadilla et al 2011).…”

Domestic and international environmental policy in Mexico

“…These diverse habitats provide economic livelihoods for millions of people and the destruction of this marine world would be detrimental to humans as well as numerous plant and animal species. Marine and terrestrial environmental policy in Mexico has been inadequate thus far in the management of these coastal zones and the preservation of biodiversity at the local, state, national and international levels (Nava & Ramirez-Herrera, 2011). Fishing has been found to lead to habitat destruction, overfishing, and wastewater pollution because of the capture, processing, conservation and transportation of the fish (Coleman & Williams, 2002).…”