By Professor Judith Rosales, PhD
Published: June 5, 2021 • World Environment Day 2021
Restoration can be designed to rehabilitate freshwater ecosystems, or achieve partial goals such as improve biodiversity, water quality, ecosystem services, ecological integrity and functionality, and/or key ecosystem taxa.
Judith Rosales ✉️, School of Graduate Studies and Research, University of Guyana – Turkeyen Campus
This essay is part of a series by the University of Guyana, Department of Environmental Studies on the United Nations Decade on Ecosystem Restoration 2021-2030. It was first published in the Guyana Chronicle on World Environment Day (June 5, 2021).
In the last decade of the twentieth century, scientists have been raising awareness about the need for maintenance of the delicate equilibrium of freshwater ecosystems, of which humans have unfortunately altered without understanding the important services they provide.
Thus, food chains, nutrient dynamics, inorganic and biochemical transformations, carbon sequestration, species diversity, species interactions, and population dynamics, are driven by the variables influencing the water cycle, the water budget, and water and sediment flows. Water residence time influences the nutrient budgets in all freshwater ecosystems, being a key factor to determine the spatial and temporal distribution, presence, abundance, and biomass of important species in freshwater ecosystems such as bacterio-plankton, phyto and zooplankton, periphyton, fungus, macroalgae, invertebrates, plants, fish, amphibia, reptiles, birds and mammals.
River bank destruction by hydraulic dredges on Micobie, Potaro-Siparuni (Region 8). Source: Amerindian People’s Association, 2021.
According to the Millennium Ecosystem Assessment, human activities that have a direct impact on ecosystems services for humans are: a) dam construction, which alters timing and quantity of river water and sediment flows; b) dike and levee construction, and highroads acting as levees, which destroy hydrologic connection between river and habitat; c) diversions that deplete stream flow habitat; d) draining of wetlands that eliminates key components of aquatic ecosystem, e) deforestation/land use, which alters runoff patterns, f) release of polluted water effluents, g) overharvesting, which depletes species populations important for humans, h) introduction of exotic species affecting native species, i) release of metals, which alters chemistry of habitat; and j) emission of air pollutants such as methane.
Restoration can be designed to rehabilitate freshwater ecosystems, or achieve partial goals such as improve biodiversity, water quality, ecosystem services, ecological integrity and functionality, and/or key ecosystem taxa. A spatial-temporal analysis must be initially conducted to identify key species and processes to restore watershed drivers, minimum flows and water residence requirements, and characteristics of the flood pulses. Eco designs based on landscape connectivity, analysis for optimising long term ecosystem functioning, ecological engineering practices, and eco technologies, are required to re-establish biochemical processes, improve population dynamics and species interactions. Restoration activities can be a) physical: major topographical corrections, creation of fish passages in areas of dams, reservoirs, dikes or roads, restoration of channel patterns such as meandering in rivers, minimum water flows, and b) biological: revegetation, phytoremediation, biomanipulation, and management of predator-prey populations. Community engagement has shown to be critical in the processes of successful restoration – not only in rural areas, but also in large cities. During the UN Decade of Ecosystem Restoration, it is the hope that freshwater projects based on applied science, clear goals, resources, multidisciplinary approaches, and scientifically-based regular monitoring, will be successfully conducted.
This essay is part of a University of Guyana series in observance of the United Nations Decade on Ecosystem Restoration 2021-2030.