Conservation challenges

The condition of the natural ecosystems in Ria Lagartos and Ria Celestun are rated as fairly good when compared with the condition of the rest of the coastal zone of Yucatan that has experienced rapid development of infrastructure for international trade ports, fishing ports, the removal of vegetation to build holiday homes and the filling in of flooded savannahs and forest for urban development (CINVESTAV, 2007).

The coastal zone land use management study for Yucatan made by CINVESTAV (2007) identifies high levels of ecosystems degradation in the central area of the coastal zone of Yucatan where the major city port ‘Progreso” is located, due to its relative closeness to Merida, the capital of Yucatan. The magnitude of development decreases in the littoral zone of Yucatan as one moves away from ‘Progreso’, although some of the environmental threats continue along the coast. For instance, coastal lagoons show the highest levels of water pollution in the central zone. This is due to urban, agricultural and industrial discharges (including the abandonment of water bodies after industrial extraction of stone for construction materials (sascaberas); organic pollution from open sky rubbish sites established on the savannahs; chemical pollution from vessel oils and boat cleaning products and lead pollution from sport shot hunting activity. Removal of sea-grasses due to constant propeller trafficand overfishing are documented in coastal lagoons of Yucatan. Much of the low-forest in the central area has been lost for urban and industrial development. Along the central coastal area half of the coastal dune vegetation has been removed for construction purposes, and between 1988 and 2004 2,832 hectares of mangrove have been lost in Yucatan. Vast areas showing signs of drying up and salinity increase are the consequence of water flow interruption from the roads (including new motorways in the central area of the coast) (CINVESTAV, 2007).

Severe beach erosion is also higher in the central zone due to the construction of ports, including the main trade port ‘Progreso’ and the main fishing port ‘Yucatpeten’ both of which are located in the central zone of the coast. Construction of breakwaters as an immediate solution to combat beach erosion extends erosion along the coast (CINVESTAV, 2007).

Ria Lagartos and Ria Celestun have been somewhat protected from much of the degradation observable in the coastal zone. Their location at the extreme ends of the

coastal zone of Yucatan, where relatively small towns are located with less road access and a lower levels of construction than in the central area of the coast. The designation of these areas as biosphere reserves increases their significance within the coastal development context in Yucatan. The areas of study, however still face challenges for conserving biodiversity at a high magnitude. These challenges have been examined in the light of data gathered from a multidisciplinary analysis conducted by Andrade (1997).

5.3.1 Biodiversity depletion

Due to an increase in fishing caused by immigration and illegal angling techniques, most of Yucatan’s aquatic species have declined dramatically in the protected areas and indeed throughout the Peninsula (Andrews, Migoya Von Bertrab, Rojas, Sastré Méndez et al., 1998). Overfishing is identified as one of the main threats in Ria Celestun (Herrera-Silveira & Morales-Ojeda, 2010b).

Habitat loss, fragmentation and hunting has contributed to the reduction of fauna and overexploitation has caused the disappearance of the manatee (Trichechus manatus) and birds such as the King Buzzard and the Toucan (Ramphastos sulfuratus) (SEMARNAT, 2000b; INE & SEMARNAP, 1999).

Moreover, approximately 122 of the flora and fauna listed in these protected areas are included on the national list of threatened and endangered species (DOF, 2001); and approximately 97 of them are included on the list of endangered species cited by CITES (SEMARNAT & CONANP, 2006: 7). Figure 5.4 shows details of the number of species listed in Mexican NOM 059 which classified categories of protection for species of animals and plants. An update on this information was made only by Ria Lagartos after modifications on NOM 059.

Number of species of fauna listed on NOM-059-ECOL-1994 in Ria Celestun

In danger of extinction 18

Threated 37

Special protection 12

Rare species 48

Celestun (INE & SEMARNAP, 1999) (INE & SEMARNAP, 1999)

Figure 5.4 Number of species listed under a category of protection under Mexican NOM 059 in Ria Celestun and Ria Lagartos. Source: NOM- 059-ECOL-1994 & NOM-059-SEMARNAT-2001 in INE & SEMARNAP, 1999, & CONANP. 2006

Examples of priority species in the NOM 059 were illustrated by pink flamingos, sea turtles and jaguars. The most important threatened species of trees are the sapodilla (Manilkara zapota), chechem (Metopium brownei), piich (Enterolobium cyclocarpum), and amates, (Ficus spp). Among the palms of the sand dunes the kuká (Pseudophoenix sargentii), chit (Thrinax radiata) and nakax (Coccotrinax readii) are the most vulnerable species (SEMARNAT, 2000b; INE & SEMARNAP, 1999).

5.3.2 Habitat fragmentation and transformation

Habitat modification, fragmentation and loss are caused by the development of ports, roads and other tourism-related construction, including summer homes in the coastal dunes. Such construction has been undertaken on a large scale throughout the Yucatan coast and, to a lesser extent, within the study areas. Some of the effects of construction outside the study areas has also adversely affected the reserves. Infrastructure development not only replaces natural vegetation but also interrupts the natural flow of sediment and water creating beach erosion (Capurro, Euán & Herrera, 2002).

The development of motorways to allow communities inside the protected areas to gain access to the rest of the state, but built to unsatisfactory design standards that would allow free water flow in the coastal lagoons has led to reduced circulation of water causing increased levels of salinity and high rates of mangrove mortality along extended areas of wetland forests (Capurro, Euán & Herrera, 2002; Andrews, Migoya Von

Bertrab, Rojas, Sastré Méndez et al., 1998). It has resulted also in the creation of areas of devastated landscape along one side of the motorway where the road obstructs water flow. This has occurred with greatest magnitude in Ria Celestun where approximately 50 per cent of the lagoon has dried up as a result of motorway construction (SEMARNAT, 2000b). Other transformations to the landscape such as the erection of electricity pylons along the roads represent a significant cause of bird mortality, as they are located across their flight paths and are not always equipped with buoys or lights to prevent collisions (Andrade, 1997; Andrews, Migoya Von Bertrab, Rojas, Sastré Méndez et al., 1998).

The high rates of deforestation were initially the result of logging to clear land for commercial coconut plantations, urban development and domestic usage (Andrade, 1997). Deforestation in Ria Lagartos is also linked to industrial salt extraction, as the large evaporation lagoons required for the process have replaced mangroves and other natural vegetation (Andrews, Migoya Von Bertrab, Rojas, Sastré Méndez et al., 1998;

Vega-Moro, Cepeda-González, Duran, Méndez et al., 2006). The management plan of Ria Lagartos talks of approximately 2,800 hectares of wetlands being modified for this purpose (SEMARNAT & CONANP, 2006: 27). The construction of artificial navigation channels is another feature that contributes to landscape transformation, hydrological change and loss of sea grass coverage (Vega-Moro, Cepeda-González, Duran, Méndez et al., 2006).

Additional habitat fragmentation is caused by forest fires. The effect of hurricanes also plays a part by removing the primary canopy to expose the more vulnerable lower strata of vegetation to the full force of the wind and increase the accumulation of branches and other organic material that dry out and easily ignite in the high temperatures of the region (SEMARNAT, 2000b; INE & SEMARNAP 1999). Fires are classified as one of the main causes of forest loss in Ria Lagrtos where use for agriculture and livestock production is often uncontrolled (SEMARNAT, 2012). Fires have a strong impact on reducing habitat and mortality for wildlife such a monkeys, jaguars, and small mammals, especially those with relatively slow mobility such as tepezcuintle, armadillos and tortoises.

Agriculture and particularly cattle ranching has also exacerbated deforestation, especially in Ria Lagartos where substantial government promotion for livestock production has been registered (Vega-Moro, Cepeda-González, Duran, Méndez et al., 2006; Andrews, Migoya Von Bertrab, Rojas, Sastré Méndez et al., 1998). In Yucatan, each head of cattle requires between 2 to 5 hectares, but in Ria Lagartos the estimations are higher due to the floodable soils with averages of between 5 to 10 hectares per head of cattle (Alcerrega-Aguirre et al, 2010). This activity represents the most serious risk of ecosystem loss in the reserve (SEMARNAT & CONANP, 2006), but it sustains an important livelihood for some local inhabitants.

5.3.3 Pollution

Lack of management of both domestic and tourist waste results in it being burnt or dumped in open, floodable spaces causing polluted living conditions (Córdoba Ordóñez, Fuentes, Córdoba-Azcarate & Ayala-Arcipreste, 2004). This has tainted the image of Celestun and the problem is also evident, albeit to a lesser extent, in one community in Ria Lagartos. In Celestun, the fisheries also constitute a significant source of organic waste and exposed faecal matter, given that 41 per cent of homes lack sanitary toilets (SEMARNAT, 2000b). Exposed faecal matter is also a source of pollution in Ria Lagartos but, again, to a lesser extent. These insanitary conditions represent a health risk as the proliferation of flies encourages the spread of disease and infection in the communities, particularly among children.

Agriculture and cattle farming are identified in Ria Lagartos as an important source of diffuse pollution based on water quality monitoring reports. In the coastal lagoon signs of eutrophication have been found and presence of pollutants associated with agrochemicals (Herrera-Silveira & Morales-Ojeda, 2010)

Chemical pollution levels in the reserves have not yet been documented, but there is a continuous discharge of oil, petrol and bleach from the use, maintenance and cleaning of fishing and pleasure boats (Vega-Moro, Cepeda-González, Duran, Méndez et al., 2006). In the future, the area is likely to become more exposed to petroleum spills and accidents as the Yucatan Peninsula has been subject to government interest in oil

exploration, although no project on has been confirmed to date (Andrade, 2010 &

Dzunum, 2010).

5.3.4 Natural disasters

Ria Lagartos and Ria Celestun are located within a broad band of hurricane and tropical storm routes. The destructive power of hurricanes affects local communities and biodiversity, both during the initial storm and afterwards. Additionally, long-term flooding is caused by the heavy precipitation and the ocean’s intrusion into the estuarine system, which modifies salinity levels and has a devastating effect on the estuarine ecosystem (Herrera-Silveira, Zaldívar-Jiménez, Teutli Hernandez, Chi Chan et al., 2005). This can result in significant levels of post-hurricane wetland mortality. Flooding is also a factor that affects the prospects for survival of flamingo chicks (Vega-Moro, Cepeda-González, Duran, Méndez et al., 2006). As described before, post-effects of hurricanes increase the magnitude of fires in the area due to the accumulation of dead vegetation material drying up.