El Gancho-Murillo

El Gancho-Murillo is a state ecological conservation zone in Chiapas, Mexico, protecting wetlands and transitional forests along the Pacific coastal plain south of Tuxtla Gutiérrez. The reserve encompasses riparian corridors, freshwater marshes, and remnant gallery forests along river systems that drain from the Sierra Madre de Chiapas toward the Pacific coast. It serves as an ecological link between upland forest zones and the larger coastal wetland complexes, including La Encrucijada Biosphere Reserve. The protected area provides critical habitat for migratory birds using the Pacific Flyway, resident reptiles, and fish communities in the river system. Local communities of farmers and fishers interact with the reserve through traditional resource use practices that the conservation zone management seeks to make compatible with biodiversity protection.

The wildlife of El Gancho-Murillo reflects its transitional position between upland and coastal ecosystems. American crocodiles and Morelet's crocodiles inhabit the river channels and freshwater lagoons, representing important populations of these species in Chiapas. Resident birds include belted kingfishers, green kingfishers, boat-billed herons, bare-throated tiger herons, and various egrets that exploit the river margins. Migratory waterbirds including shorebirds and waterfowl pass through during the October–April period. White-tailed deer, coatis, and raccoons are commonly observed in riparian forest patches. River otters have been recorded in better-preserved river sections. Freshwater turtles including the Mexican giant musk turtle use the river system. The riparian forest corridors support a diverse community of passerine birds including warblers, vireos, and tanagers during migration, making the reserve a locally significant birdwatching destination.

Gallery forest vegetation along the river channels of El Gancho-Murillo features trees adapted to periodic flooding, including Pachira aquatica (water chestnut), various Ficus species, and Inga trees that provide food for wildlife. Freshwater marsh communities with cattail, bulrush, and water hyacinth occupy wider, slower sections of the waterway. Riparian palm groves, including areas of corozo palm, characterize the coastal plain sections of the reserve. Surrounding agricultural lands are dominated by mango orchards, cacao plantations, and seasonal corn and bean fields that have replaced natural vegetation. Scattered remnant trees of species including cedar, mahogany, and ceiba persist in farm hedgerows and along drainage channels. Introduced pasture grasses cover much of the upland area adjacent to the river corridors, and management aims to restore native tree cover in buffer zones around the protected waterways.

El Gancho-Murillo occupies the lower reaches of river systems draining the granitic and metamorphic basement rocks of the Sierra Madre de Chiapas. The rivers transport sediment from the mountains and deposit it on the gently sloping coastal plain, building alluvial fans and flood plains that have been reworked over thousands of years of Quaternary fluvial activity. The reserve's flat terrain sits on thick alluvial deposits of sand, gravel, and clay that form productive agricultural soils. Near the river channels, levee deposits of coarser sand alternate with fine-grained overbank deposits that support gallery forest vegetation. The coastal plain geology is underlain by Tertiary marine sedimentary rocks at depth, buried beneath the alluvium. The entire coastal plain is subsiding slightly due to sediment compaction and groundwater extraction, which, combined with sea level rise, increases flood risk in low-lying areas of the reserve.

The climate of El Gancho-Murillo is warm and seasonally dry, typical of the Chiapas Pacific piedmont and coastal plain. Annual temperatures average 26 to 30°C, with little seasonal variation in temperature but pronounced variation in rainfall. The rainy season from May through October brings 1,200 to 2,000 millimeters of precipitation, causing rivers to rise significantly and inundate floodplain areas. The dry season from November through April is markedly arid, with rivers receding to low baseflows and marshes contracting. Hot, dry northerly winds occasionally descend from the interior highlands during winter months. Tropical storms and hurricanes from the Pacific can impact the region from June through October, bringing extreme rainfall events that cause flooding. The pronounced dry season concentrates wildlife near permanent water sources, making this the best period for wildlife observation.

The coastal plain and piedmont of Chiapas have been inhabited continuously since pre-Columbian times, with Mixe-Zoquean and later Maya populations farming the fertile alluvial soils and exploiting the river fisheries. Spanish colonialism transformed the landscape through cattle ranching and the establishment of large haciendas that consolidated land ownership. The Pacific coast of Chiapas developed a sugar economy in the colonial period, and later cacao and coffee cultivation expanded as cash crops in the nineteenth and twentieth centuries. The river systems within El Gancho-Murillo have historically provided subsistence fish, including snook, mojarra, and freshwater shrimp, to local communities. Land reform in the twentieth century redistributed some hacienda land to ejido communities, which continue to farm adjacent to the reserve boundary today.

El Gancho-Murillo was designated a state ecological conservation zone by the Chiapas government to protect riparian and wetland habitats facing progressive degradation on the Pacific coastal plain. The designation came as part of Chiapas's effort to complement federal protected areas with a state-level network covering ecologically important areas not included in federal reserves. Management responsibility falls under the Chiapas state environmental authority, which has worked with local municipalities and ejido communities on developing compatible land-use plans for areas adjacent to the core protected zone. The reserve has received support from Pronatura Sur and other NGOs active in Chiapas wetland conservation for developing management plans and supporting community environmental education. Its proximity to populated areas makes community engagement essential for reducing encroachment and illegal resource extraction.

El Gancho-Murillo is primarily visited by naturalists and birdwatchers interested in the river and wetland wildlife of the Chiapas coastal plain. The river channels can be explored by small boat or kayak, offering close-range observation of crocodiles resting on banks, kingfishers hunting from overhanging branches, and herons stalking the shallows. The dry season from November through April provides the best conditions for wildlife observation when vegetation is less dense and animals concentrate near water. Local community guides can be arranged through the nearest towns for navigation through the waterway system. No formal visitor center or established trail network exists within the conservation zone. The reserve is accessible via roads from the coastal highway system connecting Tonalá with Tapachula along the Chiapas Pacific coast. The combination of riverside wildlife, tropical forest remnants, and proximity to other coastal reserves makes the area suitable for a naturalist day trip.

Access to El Gancho-Murillo is via the coastal highway (Mexico Federal Highway 200) that runs along the Chiapas Pacific plain. The town of Tonalá, approximately 180 kilometers west of Tapachula, is the nearest service center with hotels, restaurants, and bus connections. Local roads off the coastal highway provide access to river communities near the reserve boundary. No formal entrance infrastructure exists; visitors should inquire with local communities or the Chiapas state environmental office for current access arrangements and guide availability. Accommodation is limited to basic options in nearby towns. Boat rental from fishing communities near the river mouths is the primary means of entering the wetland interior. The reserve is best visited in the dry season, and visitors should bring water, sun protection, and insect repellent. The closest airport with commercial service is at Tapachula, roughly two hours by road.

Key conservation challenges at El Gancho-Murillo include controlling the conversion of riparian forest to agriculture, managing invasive water hyacinth that clogs waterways, and protecting crocodile populations from poaching and conflict with local communities. The fragmented nature of the reserve means that biodiversity depends on maintaining ecological connections with adjacent wetlands and river sections outside the formal boundary. Community-based monitoring programs engage local fishers in recording crocodile sightings and fish catch data, building a evidence base for adaptive management. Programs supporting sustainable aquaculture of native fish species provide income alternatives to extractive practices. Climate change projections for the Chiapas Pacific coast suggest increased drought severity during dry seasons and more intense rainfall events, both of which stress the river and wetland ecosystem. Coordination with upstream municipalities on controlling agricultural chemical runoff is important for maintaining water quality within the reserve.