El colapso ambiental en el rio Patia, Colombia: variaciones morfologicas y alteraciones en los ecosistemas de

Abstract

RESUMEN. El delta del Patía ha experimentado grandes variaciones morfológicas en las últimas cuatro décadas debido a presiones antrópicas. El transvase del río Patía al río Sanquianga, debido a la construcción del canal Naranjo en 1973, y la posterior formación del brazo Patianga, han derivado en complejas problemáticas ambientales que se evidencian en la reactivación del lóbulo norte del delta y el abandono de la anterior desembocadura en el lóbulo sur. En este artículo se analizan las principales alteraciones que se presentan en el delta del Patía como producto del desvío del río y las consecuentes variaciones en el aporte fluvial y de sedimentos. Estas alteraciones se reflejan en: (1) cambios drásticos en la línea de costa, con tasas de erosión de hasta 70 m año -1 ; (2) dulcificación de los estuarios del lóbulo norte del delta, cambio hidrológico que ha ocasionando la migración de la zona alta estuarina (salinidad <1) 15 km aguas abajo; y (3) alteraciones en la cobertura vegetal del Parque Nacional Natural Sanquianga, con incrementos en la vegetación de agua dulce de hasta 42%, y disminución en la cobertura de manglar de hasta 31% en un período de 15 años. Las condiciones actuales del delta del Patía son ejemplo de la importancia de las actividades humanas como agentes de cambio dentro de la evolución de los sistemas deltaicos, y revelan la necesidad de profundizar el estudio de este delta para establecer estrategias adecuadas de manejo y conservación. Palabras clave: río Patía, río Sanquianga, deltas tropicales, erosión costera, manglares, Pacífico colombiano.The environmental collapse in the Patía River, Colombia: morphological variations and impacts on mangrove ecosystems ABSTRACT. The Patía River delta has experienced major morphological variations in the last four decades due to anthropogenic pressures. The diversion of the Patía River to the Sanquianga River as a result of the construction of the Canal Naranjo in 1973, and the former development of the Patianga River, has generated complex environmental issues that are evidenced by the reactivation of the northern delta lobe and the abandonment of the previous river mouth in the southern lobe. This paper analyzes the main alterations taking place in the Patia delta as a result of the river diversion and the consequent variations in the water and sediment discharge. This alterations are reflected in: (1) drastic changes in coastline, with erosion rates up to 70 m y -1 ; (2) freshening conditions in the Sanguianga distributary channel, a hydrologic change that has shifted the upper estuarine region (salinity <1) 15 km downstream; and (3) alterations in the Sanquianga National Park land cover with increase in freshwater vegetation up to 42%, and decrease in mangrove cover up to 31% for a 15 years period. The current conditions of the Patía River delta are a clear example of the importance of human activities as change agents in the evolution of deltaic systems, and also reveal the need of deepen in the studies of this delta and establish appropriate manag...

Epidemiology of lobomycosis-like disease in bottlenose dolphins Tursiops spp. from South America and southern Africa

“…Two cases of LLD were observed in this community in 2010 to 2011 (Table 1; Herrera et al 2013). The rivers, especially the Patía, are biologically and chemically contaminated by fertilizers used for coca plantations, by heavy metals from the mining industry, by the inadequate management of solid waste from local people and by commercial logging (PNN Sanquianga 2013, Parra & Restrepo 2014). PI surveys (29 h) were conducted opportunistically from a fibreglass boat in the waters adjacent to the park from 1 to 6 July 2013.…”

Predation risk and resource availability explain roost locations of Whimbrel Numenius phaeopus in a tropical mangrove delta

“…Sand Table 3. We do not have historical survey data, but we suspect that conditions for Whimbrels and shorebirds in general have changed as compared with 40 years ago when the Pat ıa river was partially diverted into Sanquianga estuary, increasing its volume and sediment load, and doubling the size of mudflats (Restrepo & Kettner 2012, Parra & Angel 2014. beaches and pastures also occupy a marginal proportion of the habitat (< 2%) in relation to almost 15% of the area occupied by mudflats (UAESPNN 2005).…”

“…Thus, in addition to a larger availability of mudflats, individual patches near current roosts can harbour more birds. We do not have historical survey data, but we suspect that conditions for Whimbrels and shorebirds in general have changed as compared with 40 years ago when the Pat ıa river was partially diverted into Sanquianga estuary, increasing its volume and sediment load, and doubling the size of mudflats (Restrepo & Kettner 2012, Parra & Angel 2014. It is likely that the increase in mudflats provides conditions for redistribution of Whimbrels and could have an impact on roost use; however, in the absence of historical survey data, we cannot test this.…”

Evaluación de la estructura poblacional arbórea del manglar en el Parque Histórico de Guayaquil

“…A su vez, Parra & Restrepo (2014) establecen que los manglares sirven como barreras naturales cuando suceda un aumento del nivel del agua, generado por algún fenómeno natural, como los tsunamis; esto se debe al amortiguamiento de las mareas producido por las raíces fúlcreas de la especie R/iizop/ova mangle o Rlziz/zop/zora /wrrisonü, como lo especifica el CIU (1995).…”