Pérdida de humedales y vegetación por urbanización en la cuenca del río Grijalva, México

Abstract

La periurbanización se ha considerado como motor del cambio de uso del suelo y de la pérdida de ecosistemas y de biodiversidad. A partir de esta premisa, la investigación plantea el seguimiento, desde una doble perspectiva, histórica y predictiva, de los cambios en la superficie de los humedales y en la deforestación progresiva entorno a Villahermosa, la urbe más importante de la cuenca del río Grijalva, en el Estado de Tabasco (México). Se han utilizado diferentes métodos: el análisis bibliográfico para el periodo desde la fundación de la ciudad hasta el último tercio del siglo XX, la verificación de fotografías aéreas entre 1984 y 2008 y la modelización de escenarios futuros, entre 2020 y 2040. Desde el periodo colonial hasta mediados del siglo veinte, las inundaciones y la insalubridad dificultaron el crecimiento de la ciudad pese a la transformación de la red hídrica superficial en la cuenca, iniciada mediante la construcción de diques en el siglo XVII. Posteriormente, las elevadas tasas de pérdida de humedales y deforestación (-0.50 y -4.63 %) se incrementaron por la urbanización y el impacto de los programas de producción agropecuaria y petrolización. En los últimos 40 años, el desarrollo periurbano ocasionó la pérdida de 4.008 ha de vegetación arbórea y 289 ha de humedales, con una tendencia a desaparecer 1.449 y 356 ha adicionales respectivamente en el futuro 2040. Estos resultados resaltan la necesidad de rediseñar un programa metropolitano, transdisciplinario y sustentable que respete y actualice las reservas territoriales para regular la periurbanización.

Genetic diversity, structure, and kinship analysis ofTrachemys venusta venustain Wildlife Management Units and wild populations in south Mexico. Implications for conservation and management

“…The genetic diversity of the wild population of T. venusta venusta may have declined since the UMA was founded, probably due to habitat fragmentation and water pollution [19]. Indeed, the state of Tabasco lost around 60% of its wetlands at the beginning of the 21st century, mainly due to anthropogenic activities such as the oil industry, the establishment of new crop areas and grassland for livestock use, road construction, population growth, and increased pollution derived from these activities [20, 77]. Additionally, in Tabasco state, freshwater turtles are subject to intense hunting and illegal trading and trafficking [78–80] that has contributed to a decline in population numbers leading to a loss of genetic diversity.…”

“…Turtles are still in demand for commercial and consumption purposes. In addition to this culinary practice, urban growth has increased markedly since the mid-20 th century leading to high rates of deforestation [19–20]. The city of Villahermosa, the largest urban area in the state of Tabasco, is a perfect example of such environmental degradation; over a period of only 40 years, 4,008 ha of forest vegetation and 289 ha of wetlands have been lost [20].…”

“…In addition to this culinary practice, urban growth has increased markedly since the mid-20 th century leading to high rates of deforestation [19–20]. The city of Villahermosa, the largest urban area in the state of Tabasco, is a perfect example of such environmental degradation; over a period of only 40 years, 4,008 ha of forest vegetation and 289 ha of wetlands have been lost [20]. The uncontrolled exploitation of freshwater turtles in Mexico, particularly in Tabasco, together with habitat loss, has resulted in many species of turtles being placed in the endangered category in the Official Mexican Standard (Norma Oficial Mexicana), the NOM-059-SEMARNAT-2010.…”

Water Quality Indicators in Three Surface Hydraulic Connection Conditions in Tropical Floodplain Lakes

“…Agricultural, livestock, and forestry activities are also ried out in over 70% of the study area; in contrast, aquatic emergent macrophytes c The Mezcalapa River drains the Mezcalapa Viejo, Samaria, Carrizal, Medellin-Gonzalez, and Grijalva river areas. This drainage network was modified to avoid flooding the current Metropolitan Area of Villahermosa (MAV) by the construction of five banks to divert river water (16th to 20th centuries), five dams (20th century), 207 km of embankments, 56 bridges, and an added 62 h of roads (late 20th to early 21st centuries), as well as the urban sprawl that took place over the last 50 years [36,37]. The last three hydraulic transformations are key to this study, as the dams and the urban infrastructure regulate the intra-annual water level variations in two drainage areas down-river: the Mezcalapa River and the Grijalva River, and divert the flow to avoid flooding the MAV, further changing the flow magnitude and the natural flood cycle of both rivers [38][39][40][41].…”

“…Similarly, hydraulically isolated lakes registered eutrophic or hypereutrophic conditions in the Grijalva, Illinois, and Atchafalaya River basins [6,14,27]. The biggest overlap of TCL with IL2 is attributed to the fact that this lake has a degree of urban disturbance lower than IL1, because it is at the outer limit of the urban sprawl [37,83].…”