Because New Zealand flora and fauna evolved without herbivorous mammals to graze plants or predatory mammals to eat the herbivores, when humans arrived and brought with them the Polynesian rat/kiore, several small bird species, natives frogs and beetles soon became extinct.
This was just the start of a mammal-driven mass extinction. Europeans brought pigs, goats, deer, dogs, sheep, horse, cattle, and of direct concern to braided rivers, predatory animals.
Invasive plants are also a growing – no pun intended – problem, along with human activities, both recreational and commercial: extraction of shingle, irrigation and electricity generation, and conversion of braided river margins to intensive agriculture.
A growing problem, one set to trump them all in the decades to come, is climate change. It multiplies existing threats and it also brings new threats: rising seas inundating coastal lagoons and estuaries, ocean acidification depleting marine food sources; altered weather patterns bring intensified rain, longer periods without rain, and higher temperatures; and changing ocean currents alter oceanic ecosystems including the food supply available to some river birds, especially over winter.
Strategies for managing these threats are continuously being researched and refined. Trapping pest mammals, preventing the spread of invasive weeds, and engaging with businesses and communities to help protect breeding birds and their habitats are key winning strategies being undertaken by BRaid and its partner organisations. Find out how you can get involved.