Effects of Hydroclimatic Change and Rehabilitation Activities on Salinity and Mangroves in the Ciénaga Grande de Santa Marta, Colombia

Abstract

The Ciénaga Grande de Santa Marta (CGSM), Colombia is possibly the wetland that has experienced the largest mangrove mortality on record due to modification of hydrologic connectivity and consequent hypersaline conditions. We used hydroclimatic, salinity and mangrove basal area data collected in five stations from 1993 to 2015 to study the relation between ongoing mangrove recovery, changes in salinity in the wetland and hydroclimatic changes in precipitation, potential evapotranspiration and freshwater inputs. We found that until 2015, the mangrove ecosystems in CGSM are in general terms in a path of recovery due to the combined effect of favorable hydroclimatic conditions and management operations to increase freshwater inputs into the wetland. We observed in three stations that the annual growth of mangrove basal area increased as pore water salinity decreased. Regarding surface water salinity, El Niño/Southern Oscillation explained most of the inter-annual variability in the wet season by regulating freshwater and in the dry season by regulating potential evaporation from the wetland. However, persistent channel reopening appeared to be the cause for the largest salinity decreases, whereas lack of persistent dredging slowed recovery in other areas. The monitoring of the mangrove-salinity-hydroclimate system must continue in order to increase its understanding and to avoid more recurring episodes of mangrove mortality.

Priorities and Interactions of Sustainable Development Goals (SDGs) with Focus on Wetlands

“…Wetland functions, such as nutrient and pollutant transformation and sequestration, have expanded the use of wetlands as nature-based solutions for wastewater treatment [3,50]. In fact, most scientific publications deal with the construction of wetlands for wastewater treatment but few deal with the improvement of water quality in natural wetlands [50], with only some exceptions such as the studies of References [3,23,51]. Although wetlands are still seen as "opportunities" for resource use by adequate ecosystem management [52], growing concerns over water quality relate to risks carried by wetland-dependent human communities, fishery collapses, and pollution, as society and wetland ecosystem become more integrated [53,54].…”

“…Reference [4] warns that if wetlandscapes are not used sustainably, the functions that support agriculture, as well as other food security and ecosystem services, become undermined. Furthermore, cases abound where wetland unsustainable use and development have already resulted in permanent damage to their socioecological systems and impairment of wetland functions (e.g., References [23,24]). However, the basis for making sound decisions on the manner and extent to which wetlands can be sustainably used is weak [4].…”

Integrating the Water Planetary Boundary With Water Management From Local to Global Scales

“…Beginning in the 1990s, the Colombian government developed a long-term environmental management plan for the Cienaga wetlands (Botero & Salzwedel, 1999;Vilardy et al, 2011), focused on restoring hydrological and ecological conditions by mangrove reforestation and dredging to increase freshwater inflows ( Figure 5). Mangrove cover has increased since the mid-1990s (Jaramillo, Licero, et al, 2018), but recovery is slower than expected (Röderstein et al, 2014).…”

“…Beginning in the 1990s, the Colombian government developed a long‐term environmental management plan for the Cienaga wetlands (Botero & Salzwedel, ; Vilardy et al, ), focused on restoring hydrological and ecological conditions by mangrove reforestation and dredging to increase freshwater inflows (Figure ). Mangrove cover has increased since the mid‐1990s (Jaramillo, Licero, et al, ), but recovery is slower than expected (Röderstein et al, ).The planetary boundaries framework helps identify multiple feedback mechanisms occurring at nested spatial scales that define the local safe operating space of the Cienaga wetlands (Figure ). The primary goal of local management in the Cienaga wetlands is protecting the mangrove ecosystem.…”

Determining hydrological flow paths to enhance restoration in impaired mangrove wetlands

“…Although soil salinity in both zones decreased after hydrological reconnection, by using the preferential flow paths helped to achieve greater efficiency in terms of the invested resources and time required. Furthermore, through the restoration of the flooding regimen and with the management (maintenance) of the channels, the survival of the mangroves is guaranteed in the long term (>50 years) [69,70].…”