Habitat destruction

Habitat destruction is one of five global ecological pressures affecting the ocean, along

with fishing pressure, climate change (including ocean acidification, water pollution and

the introduction of alien species or genotypes.

Damage or destruction of habitats kills the plants and animals responsible for the habitat

ecological functions and, in some cases, its survival and regeneration. This pressure

focuses on destruction of intertidal habitats and two types of subtidal habitats, soft bottom

and hard bottom. These habitats include coral reefs, sea grasses and mangrove forests,

but do not include sea ice, which is accounted for elsewhere.

ECOLOGICAL IMPACT

Habitat destruction can have a significant impact on marine abiodiversity as species

richness, abundance, distribution, genetic variation and inter-population dynamics are

affected and entire ecosystems are altered by the loss of habitat.

Destructive fishing practices (e.g. dredging, bottom trawling, shrimp farming,

dynamiting, and poisoning) can displace or destroy habitats, eliminating food, shelter

and breeding grounds for numerous species and decreasing primary production due to

increased sedimentation.

When seagrass, mangrove and salt marsh habitats are destroyed, they are no longer

able to sequester carbon dioxide (CO 2 ) from the atmosphere and significant amounts

of CO 2 , released from stored carbon, are emitted back into the atmosphere.

Ships can damage habitats with their hulls, propellers and anchors.

Divers and snorkelers can damage habitats such as coral reefs and seagrasses when in

direct contact (i.e. breaking and trampling).

The installation and maintenance of pipelines and fiber optic cables on the seafloor

can damage marine ecosystems and result in sedimentation and pollution.

HUMAN HEALTH IMPACT

Habitat destruction

Marine plants and animals are an important biological source of unique chemicals

with potential for medical use.

More than half of all new cancer drug research is focused on marine organisms

(Cesar et al. 2003).

Habitat destruction can result in a loss in commercially or recreationally important

marine species, potentially impacting opportunities for exercise, relaxation or

outdoor learning.

The destruction and loss of coastal habitats decreases shoreline protection, which can

negatively impact human lives and property.

Habitat destruction can eliminate organisms that filter sediments and pollutants,

reducing water quality and impacting human health.

ECONOMIC IMPACT

Loss and destruction of habitat for commercially harvested species (food and natural

products) can reduce food and livelihood security.

Decreased shoreline protection due to habitat loss can affect coastal communities and

industries that are exposed to climactic events (e.g., storms, floods).

Currently, half of the world population lives within 60 km of the ocean and three-

quarters of the large cities are located by the coast. By 2020, it is projected that some

60 per cent of the world population ( 6 billion) will live in coastal areas (Kennish

2002, in UNEP 2007).