Enriching the forest floor: Westland Petrels boost levels of Selenium at breeding sites

David Hawke (Department of Applied Sciences & Allied Health, Ara Institute of Canterbury,  Christchurch, New Zealand) and colleagues have published in the journal Science of the Total Environment on the contributions of Selenium by ACAP-listed Westland Petrels Procellaria westlandica to their forest-breeding environment.

The paper’s abstract follows:

“Endemic Westland petrels (Procellaria westlandica) are a remnant of extensive seabird populations that occupied the forested hill country of prehuman New Zealand. Because seabird guano is rich in Se, an often-deficient essential element, we proposed that Westland petrels enhance Se concentrations in ecosystems associated with their breeding grounds. We sampled terrestrial (soil, plants, riparian spiders) and freshwater (benthic invertebrates, fish) components from Westland petrel-enriched and non-seabird forests on the western coast of New Zealand's South Island, an area characterised by highly leached, nutrient-poor soils. Median seabird soil Se was an order of magnitude higher than soil from non-seabird sites (2.2 mg kg− 1  compared to 0.2 mg kg− 1), but corresponding plant foliage concentrations (0.06 mg kg− 1; 0.05 mg kg− 1) showed no difference between seabird and non-seabird sites. In streams, Se ranged from 0.05 mg kg− 1  (riparian foliage) to 3.1 mg kg− 1  (riparian spiders and freshwater mussels). However, there was no difference between seabird and non-seabird streams. Stoichiometric ratios (N:Se, P:Se) showed Se loss across all ecosystem components relative to seabird guano, except in seabird colony soil where N was lost preferentially. On Seabirds therefore did not enrich the terrestrial plants and associated stream ecosystems in Se. We conclude that incorporation of trace elements brought ashore by seabirds cannot be assumed, even though seabirds are a significant source of marine-derived nutrients and trace elements to coastal ecosystems world-wide.”

Westland Petrel on the forest floor, photograph by Susan Waugh 

Read of a related paper here.

Reference:

David J. Hawke, D.J., Gamlen-Greene, R., Harding, J.S. & Leishman, D. 2017.  Minimal ecosystem uptake of selenium from Westland petrels, a forest-breeding seabird.  Science of the Total Environment 574: 148-154.

John Cooper, ACAP Information Officer, 06 January 2017