Patrones de distribución y estructura de la vegetación en el gradiente de humedales costeros El Castaño, Chiapas, México

Abstract

Introduction: The characteristics of coastal wetlands are the result of hydrogeomorphological interactions between the continent and the ocean, which cause an environmental gradient, hat results in different vegetation types such as mangroves, freshwater marshes, swamp forests and palm swamps. Objective: To characterize the hydroperiod and physicochemical variables of water and soil and their effect on the distribution of vegetation in the Sistema de Humedales El Castaño. Methods: A total of 11 permanent sampling units (UM) were established by defined strata: five in the mangrove, two in swamp forest, two in freshwater marshes and two in the flooded pasture. From May 2016 to October 2017 the vegetation was characterized and the water levels and physicochemical parameters (superficial, interstitial and groundwater) were sampled monthly for: salinity, and pH; and the soil for: bulk density, humidity percentage, and redox potential. Results: Mangroves are the closest to the sea, have the lowest diversity (H: 1.66) and species richness (14), they are dominated by Laguncularia racemosa and Rhizophora mangle, have the highest values of interstitial and groundwater salinity, (> 10.8 ups), remain flooded for 4 to 12 months per year, and have a redox potential of 14.57 mV. Immediately, inland, there are remnants of the swamp forests (H: 2.18 and 18 species), dominated by Pachira aquatica, with 5 ups interstitial and groundwater salinity, flooded from 0 to 6 months per year, with a redox potential of 119.07 mV. These forests are followed inland by freshwater marshes (H: 1.92 and 16 species), dominated by Typha domingensis with 6.1 ups interstitial and groundwater salinity, flooded for 5 to 8 months per year and a redox potential of 125.9 mV. Finally, furthest inland is the flooded pasture, a modified herbaceous wetland for cattle grazing (H: 3.44 and 50 species) dominated by Paspalum conjugatum, where interstitial and groundwater salinity is less than 0.5 ups, it stays flooded for 5 to 9 months and the redox potential is 151.23 mV. Conclusions: In each type of vegetation, the structure, composition, and diversity are different, with a high turnover of species that indicates a gradient defined by salinity. The vegetation in the SHC follows the patterns of typical organization of the tropical coastal wetlands, mangroves, swamp forests and herbaceous wetlands, in this case the freshwater marshes and flooded pastures. The factor that define the distribution of the vegetation is the salinity and the gradient that is observed are a function of the hydrological dynamics that depends on the mixing of marine and freshwater.

Relationship between Carbon Sequestration and Soil Physicochemical Parameters in Northern Campeche, Mexico

“…Thus, the accumulation of salts is associated with soils with textures showing a high clay content, low permeability, and reduced leaching, promoting the concentration of salts and ions such as SO 4 2− , Cl − , Na + , Ca 2+ , and Mg 2+ , which are predominantly salt-forming agents [63]. Salinity in coastal wetlands is basically determined by hydroperiod, tidal fluctuations, seawater salinity, changes in sea level, freshwater inputs from rivers, precipitation, and groundwater [64][65][66].…”

Global Peatlands Assessment: The State of the World’s Peatlands - Evidence for Action toward the Conservation, Restoration, and Sustainable Management of Peatlands

“…Peat up to 7 m thick has been reported in Jamaica in a wetland area covering around 220 hectares, as well as on other Caribbean islands (Harty et al 1991). In Mexico, peatlands have been identified in the southern coastal plains, mainly in Veracruz, Tabasco, Campeche and Chiapas states (Rincón-Pérez et al 2020;Sjögersten et al 2021;Cejudo et al 2022).…”

“….1), Raphia taedigera dominated palm swamps, stands of mixed woody species (including Campnosperma panamensis and Symphonia globulifera), forested swamps dominated by Pachira aquatica, Annona glabra, Ficus spp., Attalea liebmannii and Roystonea dunlapiana (InfanteMata et al 2011;Moreno-Casasola et al 2012;Rincón-Pérez et al 2020) and open herbaceous swamps (with Typha domingensis, Thalia geniculata, Pontederia sagittata, Cyperus giganteus, Cladium jamaicensis, and Eleocharis spp. )(Cohen et al 1995;Phillips et al 1997;Moreno-Casasola et al 2010;Campos et al 2011;.…”

“…Such land use change due to deforestation and degradation reduces peat carbon stocks due to biomass loss and peat decomposition and alters GHG emissions (vanLent et al 2019;Hergoualc'h et al 2020).6.4.3.3. Coastal plain of Chiapas, Mexico.In the state of Chiapas, more than 20 rivers drain into a short flood plain, causing the establishment of peatlands with a high capacity to store carbon(Rincón-Pérez et al 2020;Sjögersten et al 2021). Following floods caused by hurricanesPaulina (1997) and Mitch (1998), embankments were built changing river courses(Carranza-Ortiz et al 2018;Reyes-Arroyo et al 2021).…”