Threats and Issues
|Wairio Wetland area
The quality of our wetland habitats are under threat. This means that the health and state of our native biodiversity is under threat.
What are the issues?
These threats are due to a long history of practises that were carried out for a variety of reasons. These activities were aimed to gain more productivity from the land, to add recreational value for people or for urban infrastructure. This was without realising the true value of wetlands.
Some issues that have resulted are:
- Clearing of native vegetation from wetlands and streams contributing to erosion, reduced capacity of wetlands to function and reduced habitat for native fauna
- Drainage of wetlands and digging of drains
- Grazing of stock in wetland areas resulting in the decline of native plant species
- The introduction of pasture grasses and other plants
- The introduction of animals for game hunting, domestic, fur and subsequent pest animal control
- The diversion of municipal waste and storm water into streams
- The addition of extra nutrients via fertiliser application causing excess growth of weeds
- The diversion of water for irrigation or flood protection causing low stream levels
- The disturbance and subsequent failure of nesting of birds due to dogs and 4 wheel drive vehicles
What are the threats?
The issues listed above threaten the survival of our native plants and animals. They don’t do as well as they should.
These issues also threaten the cultural health of our environment. It may mean that we can’t swim in healthy water or collect plants and animals that are a traditional food source.
Threats to native freshwater fish in Wairarapa Moana include:
- Clearing of native forest and scrub—many species have evolved to live in forested rivers and streams and these days can only be found where significant stands of native forest remain
- Drainage of wetlands—some species are wetland specialists; in the Wellington region only 2.3% of wetlands remain
- Deterioration of water and habitat quality through agricultural land-use practices, including nutrient enrichment and sediment inputs, as well as stock access to streams and riverbeds
- Deterioration of water and habitat quality through urban land-use, such as piping of streams and discharges of stormwater contaminants, eg, hydrocarbons and heavy metals and in some cases treated municipal wastewater
- Extraction of water for agricultural purposes (eg, irrigation) and urban municipal water supplies (this can leave less water in lakes and rivers for the fish)
- Instream structures, like dams, wiers and perched culverts, that impede or stop migrations of diadromous species
- Commercial fishing—whitebait, eel and flounder species continue to be commercially fished, despite declining populations of some species
- Predation and competition from introduced species, such as trout and perch.
Pest plants, pest animals, pest fish….
Introduced species of plants cope better with the extra nutrients and sediment. Read more in the Pest Plants section.
Introduced animals feed on native plants and prey on native animals. Read more in the Pest Animals section.
Introduced fish compete with, and some prey on, our native fish. Read more in the Exotic Fish section.
Content on this page was last updated: 15/02/2017 11:47am