Murdoch University Research Repository

Welcome to the Murdoch University Research Repository

The Murdoch University Research Repository is an open access digital collection of research
created by Murdoch University staff, researchers and postgraduate students.

Learn more

Burrow building in seabird colonies: a soil-forming process in island ecosystems

Bancroft, W.J., Garkaklis, M.J. and Roberts, J.D. (2005) Burrow building in seabird colonies: a soil-forming process in island ecosystems. Pedobiologia, 49 (2). pp. 149-165.

Link to Published Version:
*Subscription may be required


Soil modification via biopedturbation by burrow-building seabirds was examined in a Mediterranean, island ecosystem. Physical and chemical soil properties were compared between a colony of Wedge-tailed Shearwaters (Puffinus pacificus) and adjacent heath across a 14-month period. When compared to heath soil, the biopedturbated soil was 28% drier (6.04±5.40 vol%), had increased bulk density (by 29% to 1.30±0.11 g cm -3, 51% porosity), wetting capacity (by 83% to 0.55±0.83 molarity of ethanol droplet), hydraulic conductivity (by 266% to 398.91±252.04 mm h -1), and a greater range in soil surface temperature (31.7±6.2°C diurnally to 18.3±3.2°C nocturnally). Soil penetration resistance was reduced by 26% at a depth of 0-100 mm (326.5±122.4 kPa) and by 55% at 500-600 mm (1116.8±465.0 kPa). Colony soil also had increased levels of nitrate (by 470%), phosphorous (118%), ammonium (102%), sulphur (69%), and potassium (34%), decreased levels of iron (by 50%) and organic carbon (61%), was more alkaline, and had a 78% greater conductivity. Shearwaters deposited guano at a rate of 234.4 kg ha -1 yr -1 (dry mass). Chemical analysis of guano equated this to 50.9, 5.7, 5.5, and 3.6 kg ha -1 yr -1 of nitrogen, potassium, sulphur, and phosphorous, respectively. Experimentally constructed burrows demonstrated that digging alone can alter physical and chemical soil factors, but that changes in the nutrient profile of colony soils are predominantly guano-driven. We argue that the physical impact of seabirds on soil should not be overlooked as a soil-forming and ecosystem-shaping factor in island ecosystems, and that biopedturbation can exert major bottom-up influences on insular plant and animal communities

Item Type: Journal Article
Murdoch Affiliation(s): School of Biological Sciences and Biotechnology
Publisher: Urban und Fischer Verlag Jena
Copyright: © 2004 Elsevier GmbH.
Item Control Page Item Control Page