Topography is the key to protecting indigenous plant life and improving human health, says Victoria University of Wellington’s Amin Rastandeh.

PhD student Amin Rastandeh from Victoria University of Wellington’s School of Architecture has proposed a new way of using Wellington’s natural topography to help improve human health and address the impacts of climate change.

His study, completed over the past three years, analysed sections of Wellington’s landscape to determine how the topography could be used to help protect indigenous plant life from rising temperatures caused by climate change.

“Analysing the way the land is formed is crucial to providing suitable habitats for indigenous plant life suffering from climate change, because it shows landscape architects which parts of the city are best protected from high temperatures or extreme weather,” says Rastandeh. “It is especially important in topographically varied cities like Wellington, where the possible distribution of plants and humans is limited by the city’s landscape due to a lack of flat land to build housing on, for example.”

Rastandeh’s study suggests growing indigenous plants on Wellington’s south-facing slopes is a suitable way to protect them from the changing climate, as south-facing slopes are the coolest areas of the city and will thus be less affected by rising temperatures.

“Planting these vulnerable plants on south-facing slopes could provide the beginnings of a successful conservation plan for the Wellington area,” he says.

However, Rastandeh’s research also showed that currently only 416 hectares of Wellington’s south-facing slopes are covered in indigenous hardwoods and only 9.13ha are covered in other indigenous forest – a mere 3 percent and 0.7 percent respectively of the area covered by his study. Many more plants would need to be grown on these south-facing slopes to preserve Wellington’s biodiversity in the face of climate change, he says.

“These plants are important to Wellington’s ecosystems, so a robust conservation plan is needed to help preserve them for the future,” says Rastandeh.

His proposal would have other benefits for Wellingtonians. If indigenous plants were grown on south-facing slopes, this would leave north-facing slopes free for human habitation. North-facing slopes receive a large amount of direct sunlight and humans benefit from regular direct sunlight, says Rastandeh. However, he also says north-facing slopes that currently grow indigenous plant life should be left as they are where possible to preserve the indigenous plant life.

“Using south-facing slopes for indigenous fauna and north-facing slopes for human habitation could be a win-win for conservation, landscape architects and land-use planning practices,” he says.

Rastandeh says his results could benefit other topographically diverse cities, while his methodology could be used to help all cities plan their land-use.

“My methods could be applied to other cities to help them make informed decisions regarding the allocation of land to human use that either supports or at least does minimal harm to indigenous biodiversity,” he says.

Rastandeh also hopes to see further research in this area to test his hypothesis, looking especially at how indigenous plants already living on south-facing slopes respond to upcoming climate change.

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