The Connection Between Our Freshwater Ecosystems and Water Quality

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Insufficient knowledge about the condition of our freshwater ecosystems and water quality directly impacts our quality of life. Nevertheless, we can better understand our ecosystems with real-time, innovative technology.

Changing waterways and other factors put Aotearoa’s diverse range of species at risk, affecting our connection to freshwater and our way of life.

Aotearoa has a diverse range of freshwater ecosystems and species. Unfortunately, many native freshwater species, habitats and ecosystems continue to decline due to developing land to cities, farms and plantations, and changing waterways. These changes put native species at risk and affect our way of life and our connection to freshwater.

Additional Threats to Freshwater Species and Ecosystems

Other issues that relate to the threat of our freshwater and are affected by water quality include:

• Polluted water in urban, farm and forestry areas, as different types of pollution, affect waterways and freshwater ecosystems.
• Waterflow changes affect freshwater, as the physical waterway and flow forms make places unsuitable for living species.
• Changes in climate affect freshwater, as extensive changes are expected to exacerbate the pressure faced by our freshwater ecosystems.

The Health of New Zealand’s Freshwater Ecosystems

Ecosystems are a connection between living things and the environment. The health of our ecosystems can be measured by several factors, including habitat quality, aquatic life, ecological processes and water quality and quantity.

Water quality includes physical and chemical measures of water. In a healthy ecosystem, low contaminated water contains oxygen essential to species. Low levels of nutrients would also be evident in a healthy ecosystem – supporting healthy plant growth. In an unhealthy ecosystem, pollution harms life and interferes with natural processes, and excess nutrients in the water enable weeds to grow.

Healthy vs. Unhealthy Ecosystems

Signs of a Healthy Ecosystem

A healthy ecosystem contains various species of native plants, fish and birds. Regarding the physical habitat, the size and shape of the body of water enable such species to thrive.

Low contaminated water contains oxygen essential to species, with low levels of nutrients to support plant growth. Thus, water quantity is reflected by healthy water flows that sustain freshwater plants and animals.

The ecological processes include absorbing carbon and nutrients into healthy freshwater food webs with a natural flow.

Healthy freshwater supports Te Mana o te Wai, contributes to food production, supports primary sectors, and enhances community wellbeing.

Te Mana o te Wai refers to the vital importance of water.

Signs of an Unhealthy Ecosystem

An unhealthy ecosystem introduces dominating species, causing low diversity. In addition, the physical habitat includes unstable riverbanks and poor riverside vegetation, as in-stream barriers cause excess sediment.

Water quality decreases due to pollutants that harm life and interfere with the ecosystem’s natural processes. Excess nutrients that are not filtered allow weeds to grow. An increased amount of water causes low water levels and flows, harming the habitat and biodiversity.

Unnatural flows occur as low carbon, and nutrients are absorbed, leading to poor water quality and low biodiversity.

Unhealthy ecosystems threaten native biodiversity and pose a risk to human health, and diminish community wellbeing.

Measuring Water Quality and Ecological Health

The health of our freshwater ecosystems can be measured in various ways, including by comparing the amount and types of native and non-native fish present in the habitat and the MCI.

The MCI (Macroinvertebrate Community Index) measures river water quality and ecological health through if different organisms are present or not.

Macroinvertebrates are animals like insects with no backbone but are visible to humans. Therefore, they are a helpful way to measure river health as they remain in a small area throughout their life cycle and reflect the local conditions.

Map of New Zealand’s MCI Trends

(Source: NZ Statistics)

573 river sites were measured using the MCI. For 2008-2017, an estimate of three-quarters or 78% scored good or excellent for pollution levels. However, there is a concerning increase in likely worsening conditions.

The Contributing Factors of Our Freshwater Health Issue

Before human arrival in New Zealand, forests covered almost 80% of the land. Then, 800 years ago, settlers from Polynesia and Europe cleared forests and drained wetlands, making way for farming and settlements. This is the leading cause of the decline in species, with one-third of forest and 10% of wetlands remaining.

Converting land in New Zealand catchments into cities and towns has reduced the water quality of our rivers and lakes.

Consequences of the Ecosystem and Water Quality Issue

Ecosystems and healthy species with high-quality water provide benefits, like freshwater fish moving nutrients between different habitats. Wetland habitats store carbon as peat, regulating water flow during a storm and purifying water by filtering nutrients and sediments.

The benefits for both people and nature exist when the relationship between the two is reciprocal. For example, when people give back to nature, it creates vitality in the environment, and in return, wellbeing is uplifted when the environment is healthy.

New Zealand’s Connection to the Land

Degraded ecosystems, loss of native species and declining water quality are harmful to everyone. However, these losses are distinct because they can cause a disconnection between identity and culture for Māori.

Nature provides food, materials and seasonal instructions for managing the environment, essential for passing knowledge to the next generation. However, loss of water quality, species and ecosystems result in the quality and quantity of food reducing – affecting critical cultural values and practices.

The CHI (Cultural Health Index) uses factors important to Māori to assess the freshwater ecosystem’s health. The three components include:

• Site status
• Mahinga kai status
• Cultural stream health

Map of New Zealand’s CHI Trends

(Source: NZ Statistics)

Nine out of the 41 freshwater sites tested between 2005 and 2016 were considered very poor based on the CHI, seen in Figure 2.

The CHI provides an opportunity for water managers to incorporate Māori perspectives and values for their water quality and health when making water management decisions.

From the Freshwater Iwi Leaders Group, “Our wai (water) is an inseparable part of our whakapapa and our identity, and is a fundamental part of what drives our very existence. The future health and wellbeing of our waters are a matter of utmost importance to all iwi, as well as all New Zealanders.”

Water quality decisions are important to the health of New Zealanders and the culture and identity of Māori.

The Freshwater Ecosystem Assessing Process

Ecosystems are complex in themselves, and measuring them can be difficult. As a country, we still have insufficient knowledge about the condition of our freshwater ecosystems and species and their habitats.

There is limited high-quality information available to describe all healthy ecosystem aspects, meaning we are only about to understand some aspects and not their entirety. The freshwater crisis cannot be addressed without gathering data through water quality testing. Nevertheless, there are new and innovative products that can help educate us on water quality and help us better understand our ecosystems.

Understanding and Monitoring Water Quality

Understanding the quality of our freshwater ecosystems can be achieved through the help of real-time water monitoring technology. At RiverWatch, our goal is to empower New Zealanders to understand their ecosystems and achieve clean and swimmable rivers.

We are committed to restoring our freshwater ecosystems and helping to sustain them for the generation to come.

Get in touch with us to learn more about RiverWatch and our innovative water quality monitoring solution.

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