There are a number of threat issues to biodiversity that councils need to consider, which can be categorised as:
- general/ecosystem wide
General and ecosystem-wide issues
- Little remains of many lowland and coastal habitat types and less are legally protected. Both may be particularly vulnerable to the impacts of climate change.
- Many rare and threatened habitat types are vulnerable to irreversible loss.
- The habitats, and therefore survival, of many threatened and/or rare species are at risk from a variety of pressures.
- Migratory species are vulnerable to loss of any of the several habitats they require, and/or obstructions and other hazards along their migratory route.
- Plant and animal pest species threaten the integrity of many indigenous ecosystems and the survival of many indigenous species.
- New pest species are likely to be viable in New Zealand as a result of climate change.
- The ranges of existing pest species are likely to change as New Zealand experiences climate change.
- Certain activities allowed by existing use rights may result in ongoing adverse effects on indigenous biodiversity.
- Many modified lowland ecosystems are vulnerable to the cumulative effects of repeated small-scale modifications, such as vegetation clearance and streambed modifications.
- Vegetation clearance, even on a small scale, can damage habitats of value and/or result in habitat fragmentation and/or increase the edge effect and weed invasion.
- Burning, over-sowing and topdressing of natural grasslands decrease their biodiversity values.
- The establishment of exotic conifer forest plantations close to or within native grasslands can lead to wilding tree invasion of natural areas.
- Agricultural intensification can increase impacts of agricultural activities on native vegetation remnants, downstream freshwater, estuarine and marine habitats and ecosystems.
- Mining, quarrying and earthworks can adversely affect terrestrial and aquatic ecosystems.
- Roading and utility corridors fragment natural areas, increasing edge effects and encouraging weed and animal pest invasion.
- Settlement intensification, including subdivision and new housing, can destroy or damage sensitive habitats by habitat clearance or infilling, excessive human use of sensitive areas such as dunes, pet impacts on wildlife and weed invasion. Note: these effects need to be weighed against costs of urban expansion of settlements into greenfield and rural areas.
- Stock grazing in native forest and scrub destroys the understory and prevents regeneration. It also increases light and nutrient levels thereby encouraging weed invasion.
- Poorly contained/released farmed goats and/or deer pose a significant risk to biodiversity values in nearby native vegetation.
- Vehicle use in some ecosystems, such as beaches, dunes and river beds, can damage habitats and the species that use them.
- Important indigenous biodiversity values on some lands held by councils are not legally protected (eg, paper roads around some harbour and estuary margins, water supply catchments).
- Climate change will potentially reduce the viability of certain species at the climatic margins of their ranges. Officers of councils responsible for managing reserves, parks and other open spaces will have to consider how to cope with these shifts in biomes and their effect on migratory and non-migratory species.
- Drainage, diversion and stop-banking to lower water tables and control or divert natural waters for the purposes of increasing and/or protecting human settlement and agricultural activities can adversely impact aquatic ecosystems.
- Discharges of nutrients and contaminants (both point and diffuse) can adversely affect aquatic biodiversity.
- Impoundments and large-scale abstractions of natural waters can adversely affect aquatic ecosystems, while the flooding associated with impoundments and raised water levels can destroy riparian and riverine habitats.
- Road culverts, weirs and flood control works can create significant impediments to the migrations of diadromous fish.
- Mining and dredging of river beds and the coastal marine area, along with marine spoil dumping, can adversely affect aquatic habitats.
- Development and management of aquaculture and other facilities can adversely affect aquatic biodiversity values.
- Methods used to harvest fishery resources can adversely damage marine ecosystems (the effects of the actual harvest on fisheries resources are outside the scope of the RMA and local authorities’ control).
- The progressive acidification of oceans due to increasing atmospheric carbon dioxide is expected to have negative impacts on marine shell-forming organisms (eg, corals) and their dependent species.
- Urban development increases hard-standing areas and hence increases the volume of run-off entering watercourses immediately following a rain-fall event, which can cause flooding and erosion. Also, affects ground water levels.
- It can be difficult to resolve conflicts between some private property rights and the maintenance of biodiversity within the RMA arena. Related to this, non-regulatory methods can be ineffective and may not address the issue head-on.
- Biodiversity maintenance is at risk without access to appropriate ecological expertise and ongoing resources for management.
- While some ecosystems and species habitats may straddle local authority boundaries, council plan preparation and administration processes do not necessarily recognise or prepare coordinated strategies and programmes.
- There is often inadequate information on trends in biodiversity condition and extent for different ecosystem types to evaluate policy performance.
- Lack of overall strategic biodiversity direction and priorities to guide plan policies. Part of this response is an increasing need for good strong interagency coordination.
- Difficult for councils to prepare long-term frameworks with precise, measurable and effective objectives and policies.