Articles

 

Boletín de la Sociedad Geológica Mexicana

Volumen 70, núm. 1, 2018, p. 133 ‒ 145

http://dx.doi.org/10.18268/BSGM2018v70n1a8

Colombian Caribbean mangrove dynamics: anthropogenic and environmental drivers

Ligia E. Urrego1,*, Alexander Correa-Metrio2, Catalina González-Arango3

1 Departamento de Ciencias Forestales, Universidad Nacional del Colombia, Sede Medellín, Medellín, Colombia.
2 Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad de México, México.
3 Departamento de Ciencias Biológicas, Universidad de los Andes, Bogotá, Colombia.

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Abstract

We review the main effects of sea level rise, salinity changes, and human disturbances on mangrove forest dynamics. The effects of these drivers on mangrove communities are evaluated at centennial time scales in the light of six palynological records from the Colombian Caribbean. Despite the accelerated rates of sea level rise, increases in sea surface and air temperatures, and decreases in precipitation of the last two centuries, mangroves have shown an increasing representation in pollen records at continental and marine locations of the region. In continental settings, such expansions have been related to the offsetting of sea levels by the increasing loads of fluvial sediments since 1850 AD, and by increases in autochthonous peat accumulation in San Andrés Island. Losses of mangrove cover in the past have been related to coastal erosion, regional droughts, and salinity increases. Such processes have commonly caused mangrove die-off or changes in forest species composition. When the substrate has become more saline, or sand sedimentation has increased significantly, the composition of mangrove communities has switched towards the dominance of Avicennia germinans at expenses of Rhizophora mangle. Resprout capacity of damaged stems of Avicennia germinans seems to have been the trait that has allowed this species to increase after strong and prolonged droughts, and occurrence of strong winds, tropical storms, and hurricanes. Human disturbances are represented either by the expansion of Laguncularia racemosa and Avicennia germinans and decreases of Rhizophora mangle, or by mangrove replacement by herbaceous vegetation (grasses or crops), especially the fern Acrostichum aureum. Around 1850 AD, mangroves and beach vegetation were replaced by coconut plantations in San Andrés Island, and in the Cispatá bay swampy areas were covered with rice crops. Although after 1900 AD these crops were abandoned because of a marine incursion, Laguncularia racemosahas prevailed so far indicating pervasive anthropogenic disturbances.

Keywords: mangrove forest, Caribbean Sea, climate change, salinity, deforestation, drought, sea level.