Author(s): Hector Angarita; John Chavarro; Nelsy Verdugo; Franklin Ruiz; Juanita Gonzalez; Carlos A. Rogeliz; Daniel Ruiz-Carrascal
Linked Author(s):
Keywords: No Keywords
Abstract: Riverine floodplains and wetlands are ecosystems of high biodiversity and productivity, providing numerous benefits: stable water supply, support for fisheries, flood risk mitigation, carbon and nutrient regulation, and improved water quality. Functional floodplain ecosystems depend on hydrologic dynamics -- from local- to basinlevel -- to sustain key physical and ecosystem processes, including episodic lateral and vertical connectivity; habitat heterogeneity; transport and deposition of nutrients and organic matter; recharge of the water table; recruitment, dispersion, and colonization of plants; fish migration triggers; and access to soil moisture. Climate variability is a major factor controlling hydrologic dynamics of floodplains; under climate change, intensified variability (in terms of the magnitude or severity of extreme wet, dry, hot, and cold events) can induce large changes in floodplains dynamics, affecting their capacity to sustain ecosystem processes and the benefits they provide. Here, we present a case study of the effects of predicted mid-term climate change on hydrologic variability of a floodplain system. Our study area is in the Mompos Depression Wetlands, a 3400 km2 floodplain complex in the Magdalena River Basin (MRB) (Figure 1). The MRB comprises about 25% of Colombia’s territory between the Central and Eastern Andes. The system hosts over 226 native fish species [1], including at least 16 that migrate for reproduction from the low floodplain to the foothills of the Andes [2]. System dynamics are controlled by both local hydrologic processes, associated with fluvial morphology and topography that determine the connectivity of rivers and floodplains, and by inflows from the upstream tributary basin of approximately 2 x 105 km2. We evaluated the changes of the hydrologic dynamics as Eco-deficits and Eco-surpluses [3] of seasonal storage events associated with migratory fish ecology. Our results indicate that the compound effect of the changes in precipitation variability (characterized by amplified events at the tails of the distribution) and increased temperature will induce large deficits of seasonal water storages in the floodplain during regular to dry years, and larger flooding events during extreme wet conditions. Figure 2 summarizes the methods used in this work.
Year: 2018