Despotic, high‐impact species and the subcontinental scale control of avian assemblage structure

Abstract

Abstract. Some species have disproportionate influence on assemblage structure, given their numbers or biomass. Most examples of such ''strong interactors'' come from small-scale experiments or from observations of the effects of invasive species. There is evidence that entire avian assemblages in open woodlands can be influenced strongly by individual species over very large areas in eastern Australia, with small-bodied species (,50 g) being adversely affected. We used data from repeated surveys in 371 sites in seven districts across a region from Victoria to Queensland (.2000 km). A series of linked Bayesian models was used to identify large-bodied (!50 g) bird species that were associated with changes in occurrence and abundance of small-bodied species. One native species, the Noisy Miner (Manorina melanocephala; family Meliphagidae), was objectively identified as the sole large-bodied species having similar detrimental effects in all districts, depressing occurrence of 57 of 71 small-bodied species. Adverse effects on abundances of small-bodied species were profound when the Noisy Miner occurred with mean site abundances ! 1.6 birds/2 ha. The Noisy Miner may be the first species to have been shown to influence whole-of-avifauna assemblage structure through despotic aggressiveness over subcontinental scales. These substantial shifts in occurrence rates and abundances of small-bodied species flow on to alter species abundance distributions of entire assemblages over much of eastern Australia.

Causes and Consequences of Behavioral Interference between Species

“…For example, in Australia, the native hyperaggressive noisy miner (Manorina melanocephala) attacks most other birds. The resultant population declines of other species led to M. melanocephala being identified as a reverse keystone species by virtue of its subcontinental-scale effect on entire avifauna assemblages [55][56][57].…”

“…For example, in Australia, the native hyperaggressive noisy miner (Manorina melanocephala) attacks most other birds. The resultant population declines of other species led to M. melanocephala being identified as a reverse keystone species by virtue of its subcontinental-scale effect on entire avifauna assemblages [55][56][57].Habitat Partitioning and Coexistence The altitudinal replacements examples (above) illustrate how aggressive interference could foster coexistence between species on a regional scale where, in the absence of interference, one species might expand its niche and drive the other extinct [17][18][19]. Similar outcomes are possible on a finer geographic scale when habitats occur in a mosaic of low-and high-quality patches.…”

Long term thinning and logging in Australian cypress pine forest: Changes in habitat attributes and response of fauna

“…Using reference material (Marchant andHiggins, 1990-2006) and field guides (Morcombe, 2003;Pizzey and Knight, 2010), we assigned birds to one of three foraging strata groups (ground, shrub and canopy; Table S4) and one of four groups based on dietary specialisation, of which two (nectivorous/frugivorous and insectivorous; Table S4) had sufficient data for analyses. Based on emerging evidence that, within the range of the noisy miner, birds with smaller body mass (<50 g) are being excluded from woodland habitats in eastern Australia (Mac Nally et al, 2012;Maron et al, 2013), and indeed within our study area (Eyre et al, 2009;Maron and Kennedy, 2007;Maron, 2009), we categorised smallbodied (<50 g) vs large-bodied birds (P50 g) as a fifth functional bird group (Table S4).…”

Drivers of diversity at the local- and landscape-scale in a fire-prone landscape

“…Small passerines were classified as those species whose body size is smaller than that of the noisy miner (< 27 cm head to tail length) and therefore most susceptible to interference competition from that species (Mac Nally et al 2012). Observed species richness in a sample is generally lower than the actual species richness of an ecosystem (Hortal et al 2006;Colwell 2013), and relative completeness of species inventories can be biased even when sample effort is equal (Watson 2010).…”

“…Sites dominated by noisy miners tend to support relatively few, ubiquitous species with a predictable composition and low turnover (Maron et al 2011;Mac Nally et al 2012;Howes et al 2014). This pattern was evident in the study area, and as a result, landscapes with few noisy miners supported a higher richness of small passerines.…”