Activity

Habitats Affected

Impacts To Habitats

Shoreline armouring (?hard? structures such as seawalls, angular rock, jetties, etc, built to protect beaches and shorelines from erosion)

Intertidal and subtidal shorelines

(See altered shorelines )

•  Loss of complexity and surface area

•  Depletion of sediment supply to adjacent areas (see coastal sediment processes )

•  Increased exposure to wave energy fewer species can survive

Fishing – bottom trawling (large ships that drag weighted nets with rollers across the ocean bottom) 2

Subtidal and deep water marine areas

•  Physical destruction of bottom-dwelling plants/animals

•  By-catch (unmarketable fish species that are thrown away)

Dredging (excavation in marine or freshwater areas)

Subtidal , intertidal and freshwater habitats

•  Physical destruction of bottom-dwelling plants/animals

•  Smothering of bottom-dwelling organisms with displaced sediment

•  Fewer plants can grow in reduced light fish gills become clogged with sediment

Diking and in-filling

Estuaries shorelines wetlands

•  Productive intertidal and wetland habitat is destroyed, replaced with ecologically less valuable land use

•  Decline of commercially important species

Invasive Species

Shoreline, upland , freshwater habitats

•  Directly compete with native species for habitat, food

•  Alter structure of habitat often create dense, unproductive monocultures

Logging and vegetation removal

Upland , freshwater, marine habitats

•  Destroys structure of habitat

•  Removes organic material necessary for soil replenishment machinery disturbs soil

•  Can create erosion , which degrades water quality and causes further habitat loss

•  Less large woody debris in streams alters flow and channel characteristics

•  Reduces natural infiltration of rainwater

Log booming (storage of logs in lakes and sea ports)

Lakes, sheltered marine habitats

•  Accumulation of wood debris on the bottom of the water body smothers bottom-dwelling plants/animals

•  Chemical composition of substrate is altered

•  Decomposition of wood debris by bacteria depletes oxygen in water

Agriculture

Upland , marine, freshwater habitats

•  Replacement of diverse habitats with single- species crops (loss of wildlife habitat)

•  Possible runoff of livestock wastes, pesticides, fertilizers, into freshwater and marine environments

•  Transformation of streams into drainage ditches (less valuable habitat)

Sewage, animal wastes and fertilizer pollution

Streams, wetlands, lakes, marine areas

•  Nutrients cause explosive algae growth decomposition of algae robs water of oxygen ?dead zones? created.

•  Heavy metals and pharmaceuticals in wastes affect health of aquatic organisms

•  Sediments in sewage/animal waste may bury bottom-dwelling organisms

Industrial and automobile pollution

All habitats

•  Many substances are directly toxic to plants/animals others have long-term cumulative effects on health

•  Heavily polluted areas become ?dead zones? where few organisms can live.

Threats to Aquatic Biodiversity

Human activities are causing species to disappear at an alarming rate. It has been estimated that between 1975 and 2015, species extinction will occur at a rate of 1 to 11 percent per decade. Aquatic species are at a higher risk of extinction than mammals and birds. Losses of this magnitude impact the entire ecosystem, depriving valuable resources used to provide food, medicines, and industrial materials to human beings.

While freshwater and marine ecosystems face similar threats, there are some differences regarding the severity of each threat. Runoff from agricultural and urban areas, the invasion of exotic species, and the creation of dams and water diversion have been identified as the greatest challenges to freshwater environments (Allan and Flecker 1993 Scientific American 1997). Overfishing is the greatest threat to marine environments, thus the need for sustainable fisheries has been identified by the Environmental Defense Fund as the key priority in preserving marine biodiversity.

Other threats to aquatic biodiversity include urban development and resource-based industries, such as mining and forestry that destroy or reduce natural habitats. In addition, air and water pollution, sedimentation and erosion, and climate change also pose threats to aquatic biodiversity.

 

 

NPS Categories

• Abandoned Mine Drainage

• Agriculture

• Forestry

• Hydromodification & Habitat Alteration

• Marinas & Boating

• Roads, Highways & Bridges

• Urban Areas

o Low Impact Development

• Wetland & Riparian Management

Hydromodification activities include channelization and channel modification, dams, and streambank and shoreline erosion. A frequent result of channelization and channel modification activities is a diminished suitability of instream and streamside habitat for fish and wildlife. They can also alter instream patterns of water temperature and sediment type, as well as the rates and paths of sediment erosion, transport and deposition. Hardening of banks along waterways has increased the movement of nonpoint source pollutants from the upper reaches of watersheds into coastal waters.

Dams can adversely impact the hydraulic regime, surface water quality and habitat in the stream or river where they are located. The siting, construction and operation of these facilities have a variety of impacts on these systems.

The erosion of shorelines and streambanks is a natural process that can have either beneficial or adverse impacts on the creation and maintenance of riparian habitat. Excessively high sediment loads can smother submerged aquatic vegetation, cover shellfish beds and tidal flats, fill in riffle pools, and contribute to increased levels of turbidity and nutrients.

WWF's Global Freshwater Programme has a long history of promoting the protection of freshwater habitats. For example, about 75% of new sites included in the Ramsar List of Wetlands of International Importance since 1999 are the result of WWF?s work at different levels. 

Working with the Ramsar Convention, national governments, international river basin organizations and other institutions, our work to protect freshwater habitats includes:

• Supporting implementation of international agreements and treaties on biodiversity and wetlands

• Mainstreaming wetlands conservation into national laws and polices

• Promoting payments for environmental services (PES) for financing freshwater ecosystem services

• Assessing and increasing the representativeness of freshwater habitats in protected area networks

• Establishing freshwater conservation networks

• Restoring critical freshwater habitats

• Linking freshwater enhancements to protection of downstream estuaries and marine environments such as coral reefs