The complex interaction network among multiple invasive bird species in a cavity-nesting community

Yotam Orchan , François Chiron (1) , Assaf Shwartz , Salit Kark (2)

1 CESCO - Centre d'Ecologie et des Sciences de la COnservation
2 Department of Ecology, Systematics and Evolution. The Institute of Live Sciences

Alien invasive species have detrimental effects on invaded communities. Aliens do not invade a vacuum, but rather a community consisting of native and often other alien species. Our current understanding of the pathways and network of interactions among multiple invasive species within whole communities is limited. Eradication efforts often focus on a single target species, potentially leading to unexpected outcomes on interacting non-target species. We aimed to examine the interaction network in a cavity-nesting community consisting of native and invasive birds. We studied the nesting cavities in the largest urban park in Israel over two breeding seasons. We found evidence for a complex interaction network that includes negative, neutral and positive interactions, but no synergistic positive interactions among aliens. Three major factors shaped the interaction network: breeding timing, nesting preferences and the ability to excavate or widen the cavities, which were found to be a limited resource. Cavity enlargement by the earlybreeding invasive rose-ringed parakeet may enhance breeding of the invasive common myna in previously unavailable holes. The myna excludes the smaller invasive vinous-breasted starling, a direct competitor of the primary nest excavator, the native Syrian woodpecker. Therefore, management and eradication efforts directed towards the common myna alone may actually release the vinous-breasted starling from competitive exclusion by the common myna, increasing the negative impact of the vinous-breasted starling on the native community. As found here, interactions among multiple alien species can be crucial in shaping invasion success and should be carefully considered when aiming to effectively manage biological invasions.

Mots clés: Biological invasions; Biotic homogenization; Cavity network; Common myna; Invasion meltdown; Invasive birds; Multi-species interactions; Rose-ringed parakeet; Urban park

Domaines: Biodiversité et Ecologie

Yotam Orchan, François Chiron, Assaf Shwartz, Salit Kark. The complex interaction network among multiple invasive bird species in a cavity-nesting community. Biological Invasions, 2012, 15 (2), pp.429 - 445. ⟨10.1007/s10530-012-0298-6⟩. ⟨hal-01545584⟩