189 years after import, possums damage half of trees in rare New Zealand forest

In 1837, New Zealand imported Australian brushtail possums with the intention of establishing a profitable fur industry. However, the introduction of these animals has had far-reaching consequences that have significantly impacted the country's ecosystems. Over the past 189 years, possums have become one of New Zealand's most damaging invasive species, causing extensive damage to native trees and vegetation.

Aerial photographs taken over a rare South Island forest reveal that approximately half of the vulnerable trees in the area have been affected by possums. The animals feed on leaves, flowers, fruit, bark, and seedlings, stripping foliage and weakening tree canopies. As a result, many vulnerable trees have slowed in growth and reduced their ability to reproduce, altering the composition of entire forests and negatively impacting native species that rely on these trees for food, nesting habitat, and shelter.

The possums' ability to reproduce quickly and their lack of natural predators in New Zealand's ecosystems have allowed their population to grow unchecked. Originally brought to New Zealand for fur trade purposes, the animals have established themselves across the country, posing a major threat to native biodiversity. They consume various parts of plants, compete with native species for resources, and can even spread diseases such as bovine tuberculosis to livestock.

Aerial monitoring is crucial in managing the possum problem due to the vast coverage it provides and its ability to detect changes in the forest canopy over time. These images make the issue more tangible for the public by visually demonstrating the damage caused by possums, highlighting the importance of protecting native trees and ecosystems.