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Protecting the future of New Zealand’s freshwater ecosystems

Weeks, E., Kingsford, R.T, Taylor, A., & Joy, M.

September 2014

Conservation Science Statement No. 1

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Citation

Weeks, E., Kingsford R., Taylor A. and Joy M. (2014). Protecting the future of New Zealand’s freshwater ecosystems. Scientific Statement No. 1, 10pp. Society for Conservation Biology (Oceania), Sydney.

Authors: Weeks, E1, Kingsford, R.T.2, Taylor, A3. and Joy. M.4

1Society for Conservation Biology, New Zealand 2Centre for Ecosystem Science, UNSW, Australia 3 Department of Biological Sciences, Victoria University, New Zealand 4 Institute of Agriculture and Environment, Massey University, New Zealand

This Conservation Science Statement was peer reviewed.

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Contents

Executive Summary ............................................................................................................................. 4

The importance of freshwater ecosystems ...................................................................................... 5

Status of freshwater ecosystems and biodiversity .......................................................................... 5

Drivers of freshwater decline .............................................................................................................. 7

The future of freshwater management .............................................................................................. 8

The way forward for our rivers, wetlands and groundwater ecosystems .................................... 9

References ........................................................................................................................................ 11

Related information ............................................................................................................................ 12

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Executive Summary

Freshwater is New Zealand’s greatest asset and is a taonga of paramount importance. It is

valued for its contribution to biodiversity, recreation, the economy and overall well-being of

New Zealanders. New Zealand’s rivers, lakes, wetlands and groundwater support a unique

array of flora and fauna. They are also a vital element of whakapapa and provide valuable

resources such as mahinga kai, and underpin the country’s ever-growing tourism industry.

Reinforcing this importance, New Zealanders consider water quality to be the most important

environmental challenge facing New Zealand1.

This Conservation Science Statement uses the latest scientific understanding of New

Zealand’s unique freshwater ecosystems to propose approaches to policy and management

that safeguard these resources for future generations. We identify six clear priorities to

protect New Zealand’s freshwater ecosystems:

1. address the cumulative impacts of land use change and resulting diffuse pollution of

rivers and streams;

2. build capacity to sustainably manage freshwater ecosystems at the regional level;

3. support whole farm environmental management to control water quality impacts;

4. develop a management agenda for wetlands and groundwater ecosystems;

5. enhance the understanding of the ecological requirements to sustain native fish

habitat through Department of Conservation, the Land and Water Forum site and

other agencies and;

6. identify impacts of increased allocation on surface and ground water ecosystems and

synergies with declining water quality.

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The importance of freshwater ecosystems

Freshwater lakes, rivers, groundwater systems and wetlands provide a range of ecosystem

services for people and support a diverse array of other life. They are valued for their

contribution to biodiversity, recreation, the economy and overall well-being. Across the globe

more than 44,000 described species live in freshwater ecosystems, even though these

ecosystems cover only 0.8% of the Earth’s surface2.

New Zealand’s freshwater ecosystems are an important part of whakapapa and provide

valuable resources such as mahinga kai. More than 770 lakes and innumerable ponds cover

around 3400 square kilometres. These lakes feed into 70 major rivers systems and 100’s of

streams, and support other ecologically important ecosystems such as 73 significant

wetlands.

Freshwater ecosystems also support unique flora and fauna. There are about 50 freshwater

fish species in New Zealand, of which 31 are found nowhere else3. Half of these species

spend some part of their lives at sea, including eels and whitebait which both have important

cultural and recreational values. There are also 38 endemic species of water plants,

hundreds of native species of aquatic and semi-aquatic invertebrates from 11 orders, and

about 34 species of waterbirds4.

Many of New Zealand’s wetlands have international significance. New Zealand has six

wetlands of international importance or Ramsar wetland sites, covering 39,068 ha. These

sites are recognised for their cultural and biological significance. Historically they provided

Maori with food (particularly wildfowl, eels and other freshwater fish), taro cultivation,

harakeke (flax) for weaving and other materials for medicinal, food, building, and craft use.

Eight of New Zealand’s 27 native fish species, including inanga, short-finned eels, kokopu

and bullies, are found in wetlands, along with 47 species of rush and 72 species of native

sedge5,6. Wetlands also provide feeding grounds for migratory shorebirds.

Status of freshwater ecosystems and biodiversity

There is growing evidence that freshwater ecosystems are degrading, more so than marine

and terrestrial ecosystems, contributing to the biodiversity crises7. This is nowhere more

prominent than in our rivers, lakes and wetlands. For example, more freshwater fish species

are under threat than ever before and increasing development and demand for water is

continually pushing them closer towards extinction. In 2009, the IUCN Red List of

Threatened Animals listed 37% of freshwater species extinct or threatened around the

world8. While alarming, these trends probably underestimate the true decline of freshwater

species, due to insufficient data in many parts of the world. While only one native fish

species is extinct, many are locally extinct in some parts of New Zealand. Proportionally,

New Zealand has more threatened freshwater species than almost any country globally14.

In the last 150 years, the draining of 90% of wetlands and the removal of a similar amount of

indigenous habitat has placed much strain on the health of remaining freshwater ecosystems

in New Zealand. This has been exacerbated with recent intensification of farming, along with

the effects of urbanisation and introduction of exotic species. These cumulative impacts

have increased degradation of water quality and ecosystems.

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Water quality in New Zealand’s streams and rivers has declined for the past 25 years. This

represents a period when intensification of farming, especially dairying, has been

unprecedented. Water quality consistently declined in 77 National Water Quality Monitoring

Sites (NRWQN), monitored since 1990, particularly in lowland rivers9. Further, 96% of the

sites in 300 lowland pastoral catchments, monitored by local government, and all sites in

urban catchments failed the pathogen standard for safe swimming and more than 80%

exceeded nutrient guideline levels10.

Lakes and groundwater ecosystems parallel these declines in water quality. Thirty-two

percent of monitored lakes are now classed as polluted (eutrophic or worse) 11 (Fig. 1). In

groundwater, nitrate levels are rising at 39% of monitored sites and groundwater pathogen

levels exceed human drinking standards in 21% of monitored sites12.

Freshwater biodiversity has declined over the past century, at increasing rates over the past

40 years. Numbers of species listed as threatened have grown over the past 20 years,

accounting for changes in criteria for risk assessments. The New Zealand Department of

Conservation (DOC) recorded 10 species as threatened in 1990; by 2002 the number had

risen to 16 species13. Under the new New Zealand threatened or at risk categories, 74% of

all native taxa and 76% of all non-diadromous taxa are considered threatened or at risk14,15.

Globally, New Zealand ranks among the worst nations for freshwater invasive species16.

Twenty-one introduced species of freshwater fish have established self-sustaining

populations in New Zealand17. Exotic species outcompete or prey on native fish species.

Invasive exotic plants also threaten native species. Over 70 freshwater introduced aquatic

plants are silently invading water ways. Most recently Didymosphenia geminata (aka didymo

or rock snot) has significantly impacted on biodiversity, hydroelectric power generation,

irrigation and recreational water use.

Dams, levees and channels also cause major ecological problems to New Zealand’s rivers

and wetlands18. For example, the once mighty Kumutoto Stream now traverses pipes on its

way to the ocean in Wellington– one of our many lost urban streams. Native fish that

complete part of their life cycle at sea are particularly vulnerable to man-made barriers.

What is eutrophication?

Eutrophication occurs when water

bodies (e.g. lakes) become enriched

with nutrients. Most of these nutrients

come from fertilisers used in farming

practices. Nutrients run-off into

waterways and cause phytoplankton to

grow rapidly, resulting in an algal bloom.

These blooms suffocate marine

organisms by using up all the oxygen.

Nitrates and phosphates are the most

common nutrients responsible for algal

blooms in New Zealand. Fig 1. An example of eutrophication in an Otago waterway. www.tvnz.co.nz

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Additionally, fish adapted to high water flows such as the Torrentfish (Fig 2) can be

negatively impacted when too much water is removed for irrigation19.

Fig. 2. Torrentfish (Cheimarrichthys fosteri) only live in rapid flowing water i.e. torrents. These fish are under threat with the diversion of water and creation of dams that in turn affect water velocity. www.TeAra.govt.nz (Angus McIntosh)

Drivers of freshwater decline

Around the world and in New Zealand, there are ubiquitous threats to freshwater

ecosystems including loss and degradation of habitats, caused by river regulation and

diversions, pollution, overharvesting, invasive species, disease and climate change. The

impacts of invasive species along with water quality and reduced habitat increasingly

threaten New Zealand’s remaining native species.

Most recently, widespread of diffuse pollution has become the worst threat to freshwater

ecosystems in pastoral streams and rivers, including fine sediment nutrients and faecal

microbes from increased intensification20. Increased stocking density increased near-linearly

with specific yields of sediment, nutrients and microbes. This increased stocking rates has

increased seepage through soils of nutrient laden water.

Accelerated sediment deposition, caused by forest clearance and ineffective management of

agriculture in hill country, has considerably major impacted on fish biodiversity21. Deposited

sediment particularly affects native fish, given that most New Zealand species are benthic

and spend considerable proportion of time in the substrate below the stream bed22.

Human activities threaten New Zealand's remaining wetlands23. They continue to be drained

for urban or rural development. They are also threatened by sand and gravel extraction

which changes water levels, and damages existing vegetation along, providing access for

invasive species. There is also reclamation of lake and river margins, lagoons and estuaries,

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and draining of farm swamps continues to reduce wetland areas. Wetlands are also polluted

by excess run-off of sediment and nutrients from farmlands. Stock grazing in wetlands and

surrounding catchments damages vegetation, decreases soil stability and contributes to

pollution and poor water quality.

The future of freshwater management

New Zealand politicians and communities are debating the future management of our

freshwater ecosystems. These policies will affect the viability of different plants, animals and

other organisms that depend on these systems. The ecosystem services provided by this

freshwater environment are also critical to the quality of life of many New Zealanders.

The Freshwater Fisheries Act (1983) formally protects some introduced fish species (e.g

trout and salmon) but requires amendments to adequately protect native species (e.g.

juvenile galaxiids), threatened by introduced fish. Most threatened fish species are in

Canterbury and Otago – the ancient cradle of many of the country's native fish. However,

species once protected by their remote or high-altitude locations are starting to suffer as

human development encroaches. Scientists say without formal protection for native fish

habitat, through conservation reserves, some species will become increasingly threatened

and may become extinct.

The New Zealand Government has identified core priorities and objectives to improve

freshwater management in the new National Policy Statement for Freshwater Management

2014 (NPS-FM 2014)24. There are now national ‘bottom lines’ for water quality but this is not

enough. New Zealanders need to identify how we are going to protect our freshwater

ecosystems from continuing to decline.

Fig. 3. Rivers provide ecosystem services for many people, including clean water, food, as

well as providing a key place for recreation (e.g. Taranaki). (photo by Amanda Taylor)

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The way forward for our rivers, wetlands and groundwater

ecosystems

New Zealand needs a more holistic approach to freshwater management. Moving beyond

business as usual, the approach should encompass the multiple dimensions of freshwater

systems and integrate social and economic change. This requires investment in wider

freshwater values. While the new guidelines on water quality represent positive steps, six

urgent issues need to be addressed. If we look at the cumulative costs attempting to clean-

up current freshwater issues on the Waikato River, the Whanganui River and Lakes Taupo

and Ellesmere, they alone are already running out at hundreds of taxpayer million dollars.

And yet current policies are creating many more of these scenarios for generations to come,

when this need not be the outcome given the science we now possess.

There are six clear priorities for New Zealand’s freshwater ecosystems.

1. Address the cumulative impacts of land use change and resulting diffuse pollution

of rivers and streams.

To improve the health of New Zealand’s freshwater ecosystems, we need to manage

diffusion sourced pollution. The precedent and example for implementing this approach have

been set with a cap and trade limit on nutrient loads in Lake Taupo. This is one of many

options, providing a good national model. Alternatively, there is agreement to protect and

improve the health of the Waikato River, resulting in a claim taken to the Waitangi Tribunal

by Tainui-Raupatu. Under this co-management agreement (Waikato-Tainui 2010), Tainui-

Rauptu iwi have stated in their vision that a healthy and clean Waikato river is essential for

the health and safety of its people.

2. Build capacity to sustainably manage freshwater ecosystems at the regional level.

Regional councils play a crucial role in protecting waterways through administering resource

consents and monitoring compliance. They must be adequately resourced for

implementation and monitoring of whole farm environment plans. This includes assessing

the data, tools and information available to integrate into farm plans and the applicable

scale.

3. Support whole farm environmental management to control water quality impacts.

Most water quality issues, though not all, are generated from farms. Funding, legislation and

education is needed to ‘close the loop’ and ensure that nutrients and soils stay on farms and

do not enter our rivers. This requires funding to build wastewater dams, fencing for stock and

riparian buffer zones. Radical improvements need to reduce sediment and nutrient loads in

freshwater, particularly from intensive lowland agriculture.

4. Develop a wetland policy for lakes, other wetlands, estuaries and groundwater

ecosystems.

There is no policy for wetlands or groundwater ecosystems. This is despite their importance

and value to communities and the environment. Very little information exists on limit setting

for wetlands, nor are there specific objectives for groundwater ecosystems. There is an

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independent review of the NPS_FM proposed for 2016 to address degradation of wetlands

and identify potential solutions that mitigate impacts on the health of coastal waters.

5. Enhance the understanding of the ecological requirements to sustain native fish

habitat through Department of Conservation, the Land and Water Forum site and

other agencies.

We know little about the long-term viability of native fish habitat in New Zealand. In

particular, fish habitat requirements, impacts of soil pollution on water quality, and the most

effective methods of freshwater habitat conservation are poorly understood. New Zealand’s

significant invasive species problem warrants improved and comprehensive biosecurity

plans for detection, control and eradication of invasive species. Changes to legislation are

also required to adequately protect native fish species beyond existing harvesting and

consumption rules.

6. Identify impacts of increased allocation on surface and ground water

ecosystems and synergies with declining water quality

There are increasing allocations of river flows for agriculture. This has two major synergistic

impacts: it removes water necessary for ecosystems and increases the problems of

declining water quality because there is less fresh water to dilute problems. There is a clear

need to justify the quantity of water that is increasingly allocated, given how much in

cumulatively contributes to the increasing problems affecting freshwater ecosystems in New

Zealand.

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References

1. Hughey KFD, Kerr GN and Cullen R (2013) Public perceptions of New Zealand’s environment:

2013. EOS Ecology, Christchurch.

2. Reaka-Kudla ML (1997) The global biodiversity of coral reefs: A comparison with rain forests. In:

ML Reaka-Kudla, DE Wilson, and EO Wilson (eds), Biodiversity II: Understanding and protecting our

biological resources. Joseph Henry Press, Washington, D.C., USA. Pp. 83-108.

3. Ministry for the Environment (1997). State of New Zealand’s Environment 1997. Wellington.

Ministry for the Environment.

4. Department of Conservation (2014) New Zealand Biodiversity.

https://www.biodiversity.govt.nz/index.html

5.Johnson, Peter N; Brooke, Pat A (illustrator) (1998, 2007, 2009). Wetland plants in New Zealand.

Canterbury, N.Z.: Manaaki Whenua Press.

6. Suren A. and Sorrel B (2010) Aquatic invertebrate communities of lowland wetlands in New

Zealand. Wellington. Department of Conservation.

7. Millennium Ecosystem Assessment (2005). Ecosystems and Human Well-being: Synthesis. Island

Press, Washington, DC.

8. IUCN (2010) The IUCN Red List of Threatened Species. http://www.iucnredlist.org

9. Ballantine DJ and Davies-Colley RJ (2010) Water quality trends at NRWQN sites for the period

1989-2007. National Institute of Water & Atmospheric Research Ltd.

10. Larned ST, Scarsbrook TH, Snelder NJ, et al (2004) Water quality in low-elevation streams and

rivers of New Zealand: recent state and trends in contrasting land-cover classes. The New Zealand

Journal of Marine and Freshwater Research 38:347-266.

11. Verburg P, Hamill K, Unwin M and Abell J (2010) Lake water quality in New Zealand 2010: Status

and trends. National Institute of Water & Atmospheric Research Ltd.

12. Daughney CJ and Wall M (2007) Ground water quality in New Zealand. State and trends 1995-

2006. GNS Science Consultancy Report 2007/23.

13. Hitchmough R, and Comarty P (2007) New Zealand Threat Classification System lists.

14. Allibone R, David R, Hitchmough, et al (2010) Conservation Status of New Zealand freshwater

fish, 2009. New Zealand Journal of Marine and Freshwater Research 44: 271-287

15. Goodman JM, Dunn NR, Ravenscroft PJ (2013) Conservation status of New Zealand freshwater

fish, 2013. Department of Conservation. Wellington, NZ.

16. Joy M and Death RG (2013) Freshwater biodiversity. In Ecosystem Services in New Zealand:

conditions and trends edited by John R Dymond. Manaaki Whenua Press.

17. Dean T (2010) Invasive freshwater fish in New Zealand: DOC’s present and future management.

Department of Conservation. Wellington.

18. Young, RA, Smart, G. and Harding, J. (2004) Impacts of hydro-dams, irrigation schemes and river

control works. Freshwaters of New Zealand: 37-31.

19. McDowall, RM (1998). Fighting the flow: Downstream-upstream linkages in the ecology of

diadromous fish faunas in West Coast New Zealand rivers. Freshwater Biology 40:111-122.

20. Davies-Colley RJ (2014) River quality in New Zealand: An introduction and Overview. In

Ecosystem Services in New Zealand: conditions and trends edited by John R Dymond. Manaaki

Whenua Press.

21 Quinn JM and Stroud MJ (2002) Water quality and sediment and nutrient export from New Zealand

hill-land catchments of contrasting land use. New Zealand Journal of Marine and Freshwater

Research 36: 409-429.

22. McEwan, AJ and Joy, MK (2011) Monitoring a New Zealand freshwater fish community using

passive integrated transponder (PIT) technology; lessons learned and recommendations for future

use. New Zealand Journal of Marine and Freshwater Research 45: 12-133.

23. Johnson P and Gereaux P (2004) Wetland types of New Zealand. Department of Conservation.

Wellington.

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24. Ministry for the Environment (2014) National Policy Statement for Freshwater Management.

Wellington.

Related information

http://www.mfe.govt.nz/issues/water/freshwater/supporting-papers/

http://www.sciencemediacentre.co.nz/2014/07/03/freshwater-national-standards-set-experts-respond/

http://www.doc.govt.nz/conservation/land-and-freshwater/freshwater/

http://www.mfe.govt.nz/issues/water/

http://www.niwa.co.nz/publications/wa/water-atmosphere-7-june-2013/qa-is-new-zealand-really-clean-

and-green

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Conservation Science Statement No. 1