Biotic interactions mediate the influence of bird colonies on vegetation and soil chemistry at aggregation sites

Daniel James Deans Natusch*, Jessica Ann Lyons, Gregory P. Brown, Richard Shine

*Corresponding author for this work

Research output: Contribution to journalArticle

4 Citations (Scopus)
17 Downloads (Pure)

Abstract

Colonial-nesting organisms can strongly alter the chemical and biotic conditions around their aggregation sites, with cascading impacts on other components of the ecosystem. In tropical Australia, Metallic Starlings (Aplonis metallica) nest in large colonies far above the forest canopy, in emergent trees. The ground beneath those trees is open, in stark contrast to the dense foliage all around. We surveyed the areas beneath 27 colony trees (and nearby randomly chosen trees lacking bird colonies) to quantify the birds' impacts on soil and vegetation characteristics, and to test alternative hypotheses about the proximate mechanisms responsible for the lack of live vegetation beneath colony trees. Nutrient levels were greatly elevated beneath colony trees (especially, those with larger colonies), potentially reaching levels toxic to older trees. However, seedlings thrived in the soil from beneath colony trees. The primary mechanism generating open areas beneath colony trees is disturbance by scavengers (feral pigs and native Turkeys) that are attracted in vast numbers to these nutrient hotspots. Seedlings flourished within exclosures inaccessible to vertebrate herbivores, but were rapidly consumed if unprotected. Our results contrast with previous studies of colonies of seabirds on remote islands, where a lack of large terrestrial herbivores results in bird colonies encouraging rather than eliminating vegetation in areas close to the nesting site. In our continental study system, scavengers may rapidly dilute the spatial heterogeneity generated by the massive nutrient subsidy from bird colonies.

Original languageEnglish
Pages (from-to)382-392
Number of pages11
JournalEcology
Volume98
Issue number2
DOIs
Publication statusPublished - Feb 2017
Externally publishedYes

Bibliographical note

Copyright by the Ecological Society of America. Natusch, D. J. D., Lyons, J. A., Brown, G. P., & Shine, R. (2017). Biotic interactions mediate the influence of bird colonies on vegetation and soil chemistry at aggregation sites. Ecology, 98(2), 382-392. https://doi.org/10.1002/ecy.1642

Keywords

  • biotic interaction
  • colonial breeding
  • disturbance
  • ecosystem engineer
  • invasive species
  • soil toxicity

Fingerprint Dive into the research topics of 'Biotic interactions mediate the influence of bird colonies on vegetation and soil chemistry at aggregation sites'. Together they form a unique fingerprint.

Cite this