Figure 1. This infographic was made by the New Zealand Ministry for the Environment as part of the Environment Aotearoa 2015 report. — Figure 1. This infographic was made by the New Zealand Ministry for the Environment as part of the Environment Aotearoa 2015 report.

Environment at Risk: New Zealand

An ecological discussion of a country dependent upon its environment

New Zealand is a county unlike any other in terms of its ecology, history, and people. As the world's last landmass to be settled by humans, New Zealand became a time capsule for prehistoric flora and fauna. When the Polynesians discovered New Zealand in the 13th century, it was a land dominated by dense jungle, active volcanoes, 12 foot tall flightless Moa birds, and giant predatory eagles with 10 foot wingspans (Figure 2). Due to its long geographic isolation, New Zealand is now home to numerous endemic and endangered species of plants and animals. Additionally, with a large number of agricultural communities and a growing interest in "Hobbit tourism," New Zealand's economy relies heavily upon a sustainable and healthy environment. New Zealand's environment is currently threatened by climate change, run off from farms, marine pollution, and invasive species.

Figure 2. This image was taken from Bunce et al. 2005. It shows an artists rendering of Haast's eagle hunting a Moa. Signs of eagle attacks were found on the bones of Moa weighing up to 500 pounds.

The unique ecology of New Zealand is intimately tied to a complex and often debated geological history. According to the New Zealand Ministry of Culture and Heritage, New Zealand is currently part of a small, primarily underwater continent called Zealandia, which is divided into two moving plates. The seismic activity between the two plates produces the characteristic geology of the North and South Islands.

Around 540 million years ago, New Zealand began to form along the edge of the Gondwana supercontinent, now divided into South America, Africa, Australia, and Antarctica. Due to increased volcanic activity, around 100 million years ago, the Gondwana supercontinent began to break apart. Over the course of 15 million years, New Zealand drifted away from Gondwana and began to sink in the Pacific Ocean.

It is currently known that around the time of New Zealand's migration, much of the current landmass of New Zealand was underwater. Some geologists even postulate that the entire landmass was at one point submerged.

Around 25 million years ago, the continent of Zealandia started to split apart as the Australian and Pacific continents continued to migrate around it. As the plates collided, the current New Zealand landmass was thrust from the ocean and the two main islands took shape. Much of the current New Zealand landscape has formed only within the last 1.8 million years, called the Quaternary Period, including the formation of the Southern Alps and the movement of glaciers.

Plate tectonics and the history of geographic isolation still influence New Zealand today. The Southern Alps continue to rise and earthquakes, volcanoes, and thermal activity require constant government monitoring.

Additionally, New Zealand's millions of years of geographic isolation has produced distinctive evolutionary trends for its flora and fauna. Until human settlement in the 13th century, New Zealand was home to only four species of mammals, all of which were species of bats. As a result, New Zealand's native birds evolved to fill the open ecological niches.

Figure 3. This image of a Kiwi was taken from the New Zealand Department of Conservation. Note the Kiwi is standing upon its large hind limbs with its vestigial wings hidden. Unfortunately, since kiwis are nocturnal, I was unable to photograph one i… — Figure 3. This image of a Kiwi was taken from the New Zealand Department of Conservation. Note the Kiwi is standing upon its large hind limbs with its vestigial wings hidden. Unfortunately, since kiwis are nocturnal, I was unable to photograph one in the wild.

For example, the flightless Kiwi bird (Figure 3), which is endangered, endemic, and a distinctive feature of the national identity, evolved via convergent evolution to fill the niche of mammalian insectivores. The Kiwi evolved a long probing beak with nostrils at the tip of the beak (instead of by the eyes like most birds) to search for worms and insects in the dirt. As flightless birds, Kiwi bone density is closer to mammals than other birds and their wings are largely vestigial. The Kiwi is one of numerous examples of the New Zealand ecosystem specifically adapting to the ancient dearth of mammals and evolving unique endemic species.

One of the most significant ecological issues facing New Zealand today is invasive species, particularly the introduction of mammals. According to the Environment Aotearoa 2015 report, over 94 percent of New Zealand's land including offshore islands is infested with possums, rats, and stoats. All three of these mammals prey on the endangered indigenous birds and have devastated population viability of native species. Possums are additionally problematic because they eat native vegetation and can infect livestock with bovine tuberculosis. Current estimates place the possum population at 30 million, which out numbers humans over seven fold.

Below I summarize other key findings from the Environment Aotearoa 2015 report subdivided by the ecosystem they impact. When reading the following case studies in the Features section, it is crucial to keep this information in mind understand the environmental issues conservationists are currently facing in New Zealand.

Air - The primary source of air pollution in New Zealand is from wood and coal home heating accounting for 58 percent of the total air pollution. This number is currently declining as homes switch to cleaner fuel.

Atmosphere and Climate - New Zealand is currently responsible for 0.1 percent of global greenhouse gas emission and has reduced their emissions by 42 percent since 1990. Despite their internal decrease in emissions, the carbon dioxide concentration in the air over New Zealand has increased by 21 percent since 1972. Also due to the distribution of ozone, New Zealand has very high ultraviolet levels and incidence of skin cancer.

Fresh Water - The biggest polluter of New Zealand's fresh water rivers and lakes is agriculture. Since 1990, the amount of nitrogen leached into the soil from cattle and fertilizer has increased by 29 percent. In conjunction with increased phosphorous levels, about half of all monitored sites can foster nuisance periphyton blooms (similar to algae blooms).

Land - As previously mentioned, invasive pests are the most critical problem facing New Zealand land use. This issue is discussed further in the Zealandia case study. Additional problems include land compaction from cows and erosion.

Marine - As discussed further in the Scuba Diving case study, the most serious problems faced by the New Zealand marine ecosystems are caused by global warming, which result in changes in sea level, acidity, and temperatures. 26 percent of marine mammal species and 35 percent of seabird species are threatened with extinction. The Maui dolphin is currently the most rare dolphin in the world with an estimated 55 individuals remaining in the wild.

Despite these current environmental issues, New Zealand depends heavily upon its ecological capital. According to the Tourism Satellite Account: 2016 released by the New Zealand government, 7.5 percent of all Kiwis are employed by the tourism industry much of which is ecotourism. This represents an increase of 3.7 percent since 2015. As of March 2016, New Zealand's total annual tourism expenditure was $34.7 billion (NZD) and in the same timeframe, international tourism expenditure increased 19.6 percent. Additionally, when including both direct and indirect contribution to gross domestic product, tourism accounts for 9.9 percent of New Zealand's total GDP.

New Zealand's other primary exports include agriculture and forestry, which also clearly rely upon the environment.

Resources

Bunce, Michael, Marta Szulkin, Heather R. L Lerner, Ian Barnes, Beth Shapiro, Alan Cooper, and Richard N. Holdaway. "Ancient DNA Provides New Insights into the Evolutionary History of New Zealand's Extinct Giant Eagle." PLoS Biology 3.1 (2005): n. pag. Web.