Impact of a 'reverse keystone species' on the temporal dynamics of bird communities in Australia.

Interference competition by noisy miners Manorina melanocephala threatens small woodland bird communities in the highly modified agricultural landscapes of southeastern Australia. Noisy miners aggressively exclude small passerines from their territories promoting the biotic homogenization of communities. Here, we addressed the impact of this native species on the temporal dynamics of bird communities over a 7-years period (2010/2011–2016/2017). We explored the differences in community dynamic metrics (synchrony, stability, rate of change) between assemblages with and without presence of noisy miners. We also tested for differences in temporal beta diversity between the two categories of community. We first applied a multi-species abundance model to account for the imperfect observation process and uncertainty in species abundance. Yearly variation in species occurrence (but not in abundance) was higher in communities with presence of noisy miners, suggesting that this hyper-aggressive competitor excludes rare species and contributes to increased level of temporal turnover. In line with this, species loss was also significantly higher in communities with this competitor. These communities are also subject to greater variation in composition across years despite consisting of a smaller number of species in comparison to those without noisy miners. This translates into instability, where communities with noisy miners showed a loose equilibrium and generally exhibited little directional change. Our findings suggest that in the short term, noisy miners act as a filter, resulting in a predictable homogenization of species assemblages (small-bodied species are excluded while large-bodied ones are favored) in their presence. However, over a longer period, this species contributes to increased community instability. This study adds to the growing body of literature showing evidence of the ecological relevance that the impact of noisy miners can have on Australian woodlands. • Noisy miners increase species turnover and community dispersion across years. • Assemblages with miners show high interannual variation but this is somehow bounded. • This species not only act as a filter, but also as a disturbing agent. • The presence of noisy miners increases the instability of communities. • Conservation actions should consider long-term variability. [ABSTRACT FROM AUTHOR]