The value of coastal ecosystems through goods and services

Coastal ecosystems, including coral reefs, mangroves, salt marshes, and sand dunes, provide immense benefits to humans through a variety of resources and advantages. These benefits are categorised as goods, which are tangible materials that can be extracted, and services, which are broader benefits that support human life and activities.

Goods provided by coastal ecosystems

• Fish and shellfish - Vital sources of food and income for many communities.
• Fishmeal and animal feed - Used in agriculture and aquaculture to support livestock.
• Seaweed - Harvested for food and industrial applications.
• Salt - Extracted for culinary and industrial purposes.
• Land for settlement and farming - Provides space for human habitation and agriculture.
• Construction materials - Includes resources like sand and timber for building.

Services offered by coastal ecosystems

• Protection from storms - Acts as a natural barrier against extreme weather events.
• Harbours - Offers safe locations for boats and shipping activities.
• Shelter - Provides refuge for both wildlife and human communities.
• Recreational opportunities - Supports activities such as tourism, snorkelling, and other leisure pursuits.
• Biodiversity and wildlife habitats - Sustains a wide range of species, maintaining ecological balance.
• Natural treatment of wastes - Helps in filtering and breaking down pollutants naturally.

Threats to coral reefs and their decline

Coral reefs are among the most biodiverse ecosystems on Earth, offering significant value to humans. However, they face severe threats from human activities and environmental changes, leading to widespread degradation.

The importance of coral reefs

• Biodiversity hotspot - For instance, the Great Barrier Reef hosts over 550 coral species, 1300 fish species, and 3000 mollusc species.
• Coastal protection - Shields low-lying areas from the destructive forces of tropical storms.
• Food security - Supplies essential fish stocks, critical for the diets of many in developing nations.
• Tourism and recreation - Attracts millions annually for activities like snorkelling and diving, with over 110 million visitors to reef areas each year.

Human-induced threats to coral reefs

• Physical damage - Direct contact from humans, such as touching during diving, can kill coral at the point of impact.
• Pollution - Contaminants from urban and agricultural runoff harm coral health.
• Overfishing - Depletes fish populations, disrupting the reef ecosystem.
• Quarrying - Extraction of coral for construction materials damages reef structures.

Environmental threats and coral bleaching

Global warming causes rising sea temperatures that lead to coral bleaching, where corals expel their symbiotic algae, leading to potential death if prolonged. Surveys indicate that 22% of global coral reefs are under high threat from human activities, with another 28% facing medium threat levels.

Sequence of coral reef decline due to coastal development

1. Coastal development - Urban expansion, growth of fishing industries, commercial farming, and tourism development near reefs.
2. Primary impacts - Includes urban growth, attraction of fishing and tourism due to reef beauty, farming on coastal plains, and mining reefs for materials.
3. Secondary impacts - Leads to increased pollution, raw sewage discharge, fertiliser runoff, silting from deforestation, and eutrophication.
4. Reef destruction - Results from activities like snorkelling, diving, and pollution, causing the sea to become murky and polluted.
5. Final decline - Reef quality diminishes, fish stop feeding there, tourism drops, and reefs become more susceptible to bleaching and disease, ultimately threatening local food supplies, income, and employment.

The importance of mangroves and reasons for their destruction

Mangroves are vital coastal ecosystems that support marine life and protect human settlements. Despite their value, they are being rapidly destroyed due to various human activities.

The significance of mangroves

• Nurseries for marine life - Provides breeding grounds for fish and crustaceans.
• Wildlife richness - Supports diverse species within its unique habitat.
• Land creation - Roots trap silt at low tide, helping to form new land over time.
• Timber resources - Supplies wood for fuel and construction.
• Storm surge protection - Acts as a barrier against rising sea levels and storm surges, significantly reducing casualties during events like the 2004 tsunami, where a village with dense mangroves reported far fewer deaths compared to one without.

Causes of mangrove destruction

• Shrimp aquaculture - Accounts for 36% of global mangrove loss, clearing areas for shrimp farming.
• Deforestation - Contributes to 21% of destruction, harvesting timber for fuel and building.
• Fish aquaculture - Represents 16% of loss, converting mangroves into fish farms.
• Diversion of freshwater - Makes up 12% of destruction, redirecting water for tourism and agriculture.
• Land reclamation - Constitutes 7% of loss, creating space for tourist facilities and other developments.
• Herbicides and other causes - Herbicides account for 4% and other minor factors for 4% of loss.

The significance of salt marshes and pressures they face

Salt marshes are often undervalued but play crucial roles in coastal protection and biodiversity. They are under significant threat from human exploitation and environmental changes.

The value of salt marshes

• Silt and organic matter collection - Traps sediment, aiding in land formation and nutrient cycling.
• Nursery for marine species - Serves as a breeding ground for fish and crustaceans.
• Erosion and sea-level protection - Buffers coastlines against wave action and rising waters.

Threats to salt marshes

• Reclamation for development - Converted into farmland, industrial zones, or port facilities, often viewed as wasted space.
• Industrial pollution - Water contamination from nearby industries, especially in estuarine areas with ports and refineries.
• Agricultural pollution - Runoff of fertilisers and pesticides from adjacent farms causes eutrophication, overloading marsh waters with nutrients.
• Recreational developments - Pressure from building marinas and leisure facilities disrupts marsh ecosystems.
• Global warming impacts - Increased storm frequency and higher sea levels threaten marsh stability and survival.

Challenges facing coastal sand dunes

Coastal sand dunes, while less threatened globally compared to other ecosystems, face significant local pressures, particularly in areas like the UK, due to human activities and development.

Coastal sand dunes act as a natural barrier against erosion and storm surges, safeguarding inland areas.

Pressures on coastal sand dunes

• Recreational damage - Activities such as trail biking and horse riding cause physical disturbance, leading to vegetation loss and blow-outs, which are wind-eroded depressions in the dunes.
• Urban and industrial encroachment - Near urban areas, dunes are at risk of being built over for infrastructure.
• Tourism infrastructure - Pressure to develop amenities like golf courses and caravan parks near coastlines disrupts dune ecosystems.
• Stabilisation efforts - Planting trees to stabilise mobile dunes often destroys the natural dune ecosystem by altering its unique characteristics.