Results from beech forest sampling across the South Island confirm a widespread seeding event is underway, Department of Conservation scientists say.
Over the past two months, seed on beech trees has been measured at 23 sites from north-west Nelson to Fiordland by shooting branches from trees to get an early indication of likely autumn seed fall.
DOC ranger Joris Tinnemans shooting beech seed in the Maruia Valley
DOC scientist Graeme Elliott says the seed shooting results confirm the beech mast is proving to be a widespread event, as initially predicted from extensive spring flowering.
Dr Elliott says the amount of seed being produced varies in different areas from very heavy to more moderate but that virtually all forests sampled are seeding this year in what is looking like a 10-20 year event.
South Island beech seed sampling results 2014
“The key issue is that this is widespread seeding and looks set to fuel an explosion in forest predators like rats and stoats in a large number of places.”
“With the seed fall now well underway it’s expected rodent numbers will begin to increase towards a peak in the coming summer when stoat numbers will also explode.”
Dr Elliott says field teams will be closely monitoring rat and stoat numbers over the next few months for early signs of rising numbers.
The Department of Conservation says plans to counter the expected rising predator numbers are already well underway.
The Battle for our Birds pest control response—announced by the Minister of Conservation in January—aims to protect vulnerable native bird, bat and snail species with aerial 1080 and ground-based pest control operations in multiple beech forest areas the length of the South Island.
DOC field staff are monitoring seed fall and rodent and stoat numbers in these areas and consulting with affected communities. This information will inform decisions about the pest control response in the coming months including exact operational areas, timing and mix of pest control tools.
DOC has undertaken seed sampling from the canopy of beech trees for the last four years. Of the 23 sites sampled this year, seven were new sites while the rest had been measured previously. Most of the previously sampled sites (14 of 16) had the highest seed counts of at least one beech species since monitoring began. Beech trees typically seed every 2-6 years.
The Battle for our Birds programme is targeting extra protection this year for at risk populations of mōhua, kākāriki/parakeet, three kiwi species (Haast tokoeka, rowi and great spotted kiwi/roroa), whio/blue duck, kea, kākā, rock wren, giant land snails and native bats.
Places identified for a beech mast pest control response include areas in Kahurangi, Abel Tasman, Arthur’s Pass, Westland, Mt Aspiring and Fiordland national parks, and other conservation land in Marlborough, Canterbury, the West Coast and Otago.