Impacts of Cycle Gabrielle has caused the largest ever recorded decline in the region’s native river and coastal bird population.
Ecologist Nikki McArthur said the survey results highlight how catastrophic the cyclone was for river and coastal habitats.
“These endangered birds are an essential part of our coastal and freshwater ecosystems and contribute to healthy biodiversity, but they face many threats to their survival,” McArthur said.
This was announced in a report by the Hawke’s Bay Regional Council.
Baseline surveys to monitor and understand trends in numbers and distribution were undertaken between 2019 and 2021.
Between October 2023 and February the 321 kms of the Hawke’s Bay coastline and 292 kms along Tukutuki, Ngaruroro and Tūtaekuri rivers were re-surveyed.
“These surveys highlight the high degree of vulnerability these species have to extreme weather events and climate change, in addition to existing threats like predators and disturbance.”
McArthur said it was evident that there were significant decreases across several species when comparing data to pre-cyclone results.
There was a 51 per cent decrease in numbers of Pohowera (banded dotterel) on Tūtaekurī River, and 20 per cent drop on the Ngaruroro River. Along the coast Pohowera were reduced by 31 per cent. This represents a 17 per cent drop in the regional breeding population.
These are the steepest declines to have been recorded since bird surveys began in 1962.
“This equates to an estimated 2.5 percent decrease in the national and global population, assuming these declines were the result of mortality, rather than a change in distribution,” McArthur said.
The regional population of the river-breeding black-fronted dotterel declined by 30 per cent across the three rivers and the coastal-breeding tūturiwhatu (New Zealand dotterel) declined by 36 per cent.
Each of these results represent the largest population declines ever observed for these species in Hawke’s Bay.
“The Tūtaekurī, Ngaruroro and Tukituki River catchments support internationally and nationally significant populations of indigenous shorebirds, including 13 percent of the global population of pohowera,” said McArthur.
Many of these species are classified as At-Risk and Threatened by the Department of Conservation and thus McArthur says these historic declines are very concerning.
“But there’s work we can do in our communities to help offset these losses. Protecting and enhancing habitats by implementing wide ranging predator control, minimising disturbance from people and vehicles, and keeping dogs on leads and cats inside at night during the nesting season are all things we can do to help.”
In the long term, McArthur said the Regional Council will need to look at planning coastal defences and coastal retreat to allow room for coastal habitats to move inland with climate change.