Threats to Coastal and Marine Ecosystems
The world’s coastlines are home to over 40% (1) of the global population and it is where majority of the megacities are found (2). At the interface of land and sea are coastal and marine ecosystems, some of the world’s most productive but also degraded ecosystems (see table below for a list of coastal and marine ecosystems found in Sri Lanka) (3).
Crain et al., (2009) lists the following as some of the biggest threats to coastal marine ecosystems:
- Habitat loss: some habitats are directly removed (to increase space for expanding industries), or lost due to degradation as a result of many factors. Due to the relative irreversibility of these types of threat, loss of habitat is a significant threat to these ecosystems.
- Over-exploitation of resources
- Pollution: introduction of organic and inorganic pollutants as a result of inland human activities
- Disease outbreak (4)
Another threat to these ecosystems is climate change. As of now, many ecosystems have already undergone damage as a result of climate change. If current conditions continue, the Intergovernmental Panel on Climate Change (IPCC) predicts a temperature increase of 1.5 °C, with high confidence, between the years of 2030 and 2052. With this increase of 1.5 °C, intensification and frequency of extreme weather conditions such as heavy rainfall is predicted to increase. Furthermore, it is predicted increasing temperatures will change the range of marine species, shifting them to higher latitudes. It will also raise the rate of loss of coastal resources, and reduce productivity levels of industries such as fisheries and aquaculture. The IPCC predicted with medium confidence that under a temperature increase of 1.5 °C, the annual catch of marine fisheries will reduce by 1.5 million tonnes. Ocean acidification (due to increasing carbon dioxide levels in the ocean) is predicted worsen the impacts of global warming on the coastal marine environment (5).
The chart below depicts the level of impact global warming (at 1 °C, 1.5 °C and 2 °C) has on selected sectors, communities and ecosystems. The letters L, M, H, VH indicate the level of confidence in the data and the colours relay the severity of the impacts. Warm water corals are at most risk as seen in the chart. It is predicted that coral reefs will see a decline of 70-90% under 1.5 °C and a 90% decline under 2 °C (5).
The chart above is adapted from the IPCC’s latest report, Global Warming of 1.5 °C – Summary for Policymakers.https://www.ipcc.ch
Coastal and Marine Ecosystems in Sri LankaExcluding lagoons, Sri Lanka has an estimated coastline of 1,620 km (6). The table below names some of the ecosystem services provided by the above coastal ecosystems, as listed in the National Biodiversity Strategic Action Plan 2016-2022 (5). (Please click on them to read more information about these ecosystems).
|Coral Reefs||Food, medicines,||Erosion regulation,||Provision of habitats||Aesthetic value, recreation and eco-tourism|
|Seagrass meadows||Food||Water purification, carbon sequestration,||Primary production, water cycling, provision of habitats||Recreation and eco-tourism|
|Salt marshes||Water regulation, erosion regulation, carbon sequestration,||Primary production, water cycling, provision of habitats|
|Mangroves||Food, fibre, timber, medicines,||Air quality regulation, water purification, water regulation, erosion regulation, climate regulation, carbon sequestration,||Soil formation, primary production, nutrient cycling, water cycling, provision of habitats||Aesthetic value, recreation and eco-tourism|
|Beaches||Provision of habitats||Aesthetic value, recreation and eco-tourism|
|Tidal flats||Food||Water regulation, erosion regulation,||Soil formation, provision of habitats|
|Lagoons||Food||Water regulation, erosion regulation,||Provision of habitats||Aesthetic value, recreation and eco-tourism|
|Estuaries||Food||Water regulation, erosion regulation,||Provision of habitats||Aesthetic value, recreation and eco-tourism|
|Sand dunes||Erosion regulation,||Provision of habitats|
The Coast Conservation and Coastal Resource Management Department is the focal Government organisation responsible for the conservation and management of Sri Lanka’s coastal resources, while the Marine Environment Protection Agency oversees the management of marine resources and pollution. The National Aquatic Resources Research and Development Agency is the key Government authority responsible for conducting research on all aquatic resources to improve management of these resources.
The Department of Wildlife Conservation oversees the conservation of protected species found in the marine and coastal environments. The Department of Fisheries and Aquatic Resources is responsible for managing the fisheries industry in a sustainable manner to reduce and limit negative impacts on the marine ecosystem. For more information, see Marine Protected Areas and Government Institutions and Acts Protecting Marine and Coastal Resources.
- The effectiveness of coral reefs for coastal hazard risk reducton and adaptation. Ferrario, Flippo, et al. 3794, s.l. : Nature Communications, 2013, Vol. 5.
- Future Coastal Population Growth and Exposure to Sea-Level Rise and Coastal Flooding – A Global Assessment. Neumann, B, et al. s.l. : PLOS ONE, 2015.
- Millennium Ecosystem Assessment. Ecosystems and Human Well-being: Synthesis. Washington : World Resources Institute , 2005. 1-59726-040-1.
- Understanding and Managing Human Threats to the Coastal Marine Environment. Crain, Caitlin, et al. 1162, s.l. : The Year in Ecology and Conservation Biology, 2009.
- IPCC. Global Warming of 1.5 °C – Summary for Policymakers above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts . Global Warming of 1.5 °C. An IPCC Special Report on the impacts of global warming of 1.5 °Cabove pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. [Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani,W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy,T. Maycock, M. Tignor, and T. Waterfield (eds.)]. Geneva : World Meteorological Organisation, 2018.
- Ministry of Mahaweli Development and Environment . National Biodiversity Strategic Action Plan 2016-2022. Colombo : Ministry of Mahaweli Development and Environment , 2016. 978-956-8396-05-09.
- Lieske, Ewald and Myers, Robert. Coral Reef Fishes – Caribbean, Indian Ocean an Pacific Ocean Including the Red Sea. s.l. : HarperCollinsPublishers , 1994 . ISBN 0 00 219974 2.
- Biodiversity of Sri Lanka. Gunuatilleke, Nimal, Pethiyagoda, Rohan and Gunatilleke, Savitri. Special Issue, s.l. : Journal of Natural Science Foundation Sri Lanka , 2008, Vol. 36.