There are many areas of the oceans that are suffering from manmade habitat destruction, but coastal areas are disproportionately affected. Humans show a preference for living near water – nearly two-thirds of the world’s population lives within 60 km of a coast.1
As the global population grows, coastal land use and development increases. With development come far-reaching impacts on coastal ecosystems and the species dependent on them. Coastal areas are home to over 90% of all marine species, and these habitats are being lost at an alarming speed.Coastal habitats include estuaries, marshes, mangrove ecosystems, sea grass, and coral reef. These habitats serve as nurseries, breeding grounds, feeding spots, and the destruction of these habitats afflict repercussions to dependent species. An altered population structure of a species causes a domino effect throughout the whole chain web. And habitats don’t exist in isolation; most of them have inputs and outputs to other habitats that are, in turn, set off balance as well.
Escalating pressures to develop coastlines for industrial purposes are increasing the rate of habitat destruction. Some causes are poorly designed development projects for residential or and commercial establishments; shipping port construction; shipping operations such as dredging, levees, and breakwater structures; chemical runoff; oil and gas related activities, water pollution, and the alteration of freshwater inflows. Spills of crude oil change the population distribution of, or even kill, hundreds of marine species and leave a toxic environment that can persist for years. Oil sediment has been detected as much as thirty years after an oil spill. The Rena oil spill in the Bay of Plenty, New Zealand killed an estimated 20,000 sea birds. 2
Another major ecological impact derives from the sediment remains of logging. When sediment loads enter the sea, it limits the penetration of the sunlight that primary and secondary producers need, thus modifies the whole food web. The sediment also smothers coral reefs and threatens dependent marine life. Coral reefs are critical, as they make up less than 1% of the ocean’s surface, but are home to 25% of all marine life. 3
NATURE TOURISM AND RECREATION
As travel becomes cheaper and more widespread, nature tourism and recreation become a persistent cause of disturbance to coastal ecosystems. Tourism brings millions of scuba divers, snorkelers, kite surfers, and bird watchers into direct contact with reefs, wetlands, and mangrove forests. Well-meaning nature enthusiasts may unknowingly damage habitats with their boat anchors, fishing gear, and improper diving or snorkelling practices.
Agriculture is a necessity for human sustenance that has unfortunate effects on coastal habitats. Fertilizer, sewage, and soil runoff are a direct cause of eutrophication. During this process, the excess nutrients from runoff, rich in nitrogen and phosphorus, stimulate growth of algae in what is called an “algal bloom”. Algal blooms block sunlight and deplete the water and reefs of oxygen, which is required by the zooxanthellae in coral to photosynthesize and remain alive. Almost 600 square miles of reef have disappeared every year since the 1960s. This means the reefs are disappearing twice as quickly as tropical rainforest are. 4
Aquaculture – fish and shellfish farming – are responsible for severe declines of productive ecosystems. Aquaculture may alter natural drainage patterns, increase salinity, or pollute coastal waters with pollutants and sediments.
An ecosystem that has been significantly disturbed by aquaculture is the mangrove forest. Commercial shrimp farming is responsible for 25% of all mangrove destruction! 5
As habitats disappear, not only marine species but also human communities suffer from the loss of resources. Healthy mangrove forests provide a habitat and nursery for fish species, filter salt water, collect sediment and protect erosion, and act as a buffer zone and protection from the impacts of storms and floods. In the past decades, 35% of all mangrove forests have vanished.6 Such a drastic loss spells out an increased exposure to natural forces.
HOW CAN I HELP?
While it’s hard to control the frightening rate of human population growth and the decisions of landholders and construction companies, you can take small steps to support the restoration and protection of coastal habitats.
1. Support and donate to the creation of marine parks, biosphere reserves, and Marine Protected Areas, where development is limited and fishing is prohibited.
2. Be a conscious consumer. Buy organic produce grown without pesticides, fertilizers, and other toxic chemicals. Carry a sustainable seafood guide so you can choose seafood obtained with nondestructive methods.
3. Support legislation that bans the dumping of sewage and chemicals into the oceans.
4. Be an ecologically respectful tourist by educating yourself on the impact your mode of recreation may have on local ecosystems. Ask your dive shop, tour guide, or tour boat what steps they take to insure a no-impact experience.
UN Atlas of the Oceans: Coasts and Coral Reefs. 2012.
Fragile Earth. Mysterious Mass Animal Death List. 2012
Roberts et al. Marine biodiversity hotspots and conservation priorities for tropical reefs. Science, 295. 1280-1284. 2002.
Center for Ocean Solutions. Pacific Ocean Threats & Impacts: Habitat Destruction. 2012.
Save Our Seas Foundation, Habitat Destruction. 2012.
Millennium Ecosystem Assessment (2005) Ecosystems and Human Well-being: Synthesis Ip.2) Island Press, Washington DC. World Resources Institute ISBN 1-59726-040-1