The native versus alien dichotomy: relative impact of native noisy miners and introduced common mynas (original) (raw)
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Landscape Ecology, 2011
We explored the effects of a purported 'reverse keystone species', the Noisy Miner (Manorina melanocephala) using a long-term, large-scale dataset. Specifically, we identify whether this aggressive bird affects the landscape distribution patterns of other avifauna, by displacing them into, or restricting their distribution to, less productive areas, and in so doing, adheres to 'isoleg theory'. We sought to determine the effect of abundance of the Noisy Miner on the abundance of other birds (individual species and groups), and determine whether that effect was consistent with varying site productivity, using a negative binomial distribution with a logarithmic link function, and an offset variable to account for variations in search effort. Relationships between abundance of Noisy Miners and habitat variables were examined using a Poisson distribution with a logarithmic link function scaled for extra-variation (quasi-Poisson regression). We demonstrate that when Noisy Miner abundance is low, many small passerine species are more abundant on high productivity sites. However, as Noisy Miner abundance increases, small passerine abundance decreases, with this decrease most apparent on productive sites. The same patterns were not evident for birds considered 'non-competitors' of the Noisy Miner. We identify that both site productivity and vegetation structure influence the abundance of the Noisy Miner. We reveal that the species increasingly tolerates 'less desirable' habitat attributes with increasing site productivity. The preference of the Noisy Miner for productive areas is likely to have deleterious impacts on the long-term survival and reproductive success of other Australian woodland bird species, many of which have already undergone severe declines. Keywords Reverse keystone species Á Isoleg theory Á Noisy Miner Á Manorina melanocephala Á Temperate woodlands Á Conservation management Á Woodland avifauna Electronic supplementary material The online version of this article (
Emu, 2012
Invasive species present economic and ecological challenges worldwide. In many cases we are not aware of the full effect they have on the environment, the extent of any damage, or the factors contributing to their success. In this study we examined the foraging aggression of wild Common Mynas (Sturnus tristis) as a potential explanation for their invasive success, and quantified the effect of this behaviour on other birds. Common Mynas did not display significantly more aggression than other species, and displayed significantly less aggression than native Australian Magpies (Cracticus tibicen). Furthermore, the presence of Common Mynas at a feeding resource had no greater effect on the abundance of heterospecific individuals than the presence of any other species. Presence of each species was negatively correlated with the presence of other species, that is all species were less likely to approach the feeding station if any other species was present there. Common Mynas also did not displace other birds at feeding sites any more frequently than three of the other four species, and less frequently than two other native species. Overall, the findings suggest that Common Mynas do not display more foodrelated aggression than other species in suburban habitats, suggesting that competitive aggression over food is not likely to be one of the behavioural traits leading to the success of Common Mynas in suburban habitats.
The effect of Noisy Miners on small bush birds: an unofficial cull and its outcome
Pacific Conservation Biology, 2008
This paper documents the bird community in a small (~15 ha) patch of remnant woodland New South Wales sheepwheat belt (i) before Noisy Miners Manorina melanocephala were abundant in the patch (1972-79), (ii) after a dense miner colony became established (1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988)(1989)(1990), (iii) after the miners were removed and, subsequently, (iv) while extensive, dense plantings of native trees became established (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006). Bird species richness in the patch was, respectively, 64, 18, 45 and 83 species in each time period. Totals for small (<120 g) bush birds, mostly insectivorous passerines, were 26, 0, 22 and 46 species in the respective time periods. Although this was an unofficial, unreplicated and uncontrolled activity, the results support those of previous similar studies that indicate that Noisy Miners are a major contributor to the local decline of many woodland birds. The results also affirm the value of a shrub layer to small birds.
Emu - Austral Ornithology, 2011
Many of eastern Australia's woodland birds have declined in recent decades. Although historical landscape transformation ultimately underlies these declines, effective conservation action requires knowledge of the relative importance of current threats to woodland birds. Through a literature review and analysis of empirical data from seven woodland regions, we investigated the relative importance of habitat structure, site context and aggressive avian competitors (miners, Manorina spp.) for woodland birds in eastern Australia. The literature review revealed that the factor which most consistently influenced the richness, abundance and assemblage composition of woodland birds was the density or presence of Manorina honeyeaters. A positive effect of site structural complexity was also often reported, but the effects of area, isolation and grazing varied among the reviewed studies. Across the seven empirical datasets, density of Manorina honeyeaters was responsible for the great majority of the independently explained variance in all but one region. We conclude that interspecific competition with Manorina honeyeaters is one of the most important and widespread processes threatening woodland birds in eastern Australia. In regions where this threatening process is prevalent, the greatest conservation gains for woodland birds may therefore be achieved by focussing on reducing habitat suitability for aggressive Manorina honeyeaters.
Diversity and Distributions, 2015
Aim Strongly interacting species have disproportionately large ecological effects relative to their abundances or biomass. We previously developed two conceptual models that described how one such strong interactor, the Australian bird the noisy miner Manorina melanocephala: (1) establishes resident high-density and hyperaggressive colonies and (2) in doing so, affects other biota and ecosystem processes. Here, we evaluate parts of those models relating to noisy miner habitat preferences and effects on bird assemblages using data from across the geographical range of the miner.
Life
The wildlife trade has facilitated the introduction of invasive non-native species, which may compete with native species for resources and alter ecosystems. Some of these species have great potential to become invasive if released or escaped from captivity. Here we studied the pet trade in a group of open countryside birds, the mynas (Acridotheres spp.) in Indonesia, and identified the areas that are at high risk of facing the establishment of these species. Mynas are among the most invasive birds in Southeast Asia. Once established in a new area, they are almost impossible to eradicate and can have strong negative impacts on the ecosystem. Preventing their introduction is therefore essential. Yet, invasive non-native mynas continue to be traded openly. We present data on the trade in seven species of mynas on Java, Bali and Lombok, with three species being native to parts of one or two of these islands, but not to the remainder, and four that are non-native to the region. From 201...
Ecology and Evolution, 2014
Invasive alien species can have serious adverse impacts on both the environment and the economy. Being able to predict the impacts of an alien species could assist in preventing or reducing these impacts. This study aimed to establish whether there are any life history traits consistently correlated with the impacts of alien birds across two continents, Europe and Australia, as a first step toward identifying life history traits that may have the potential to be adopted as predictors of alien bird impacts. A recently established impact scoring system was used in combination with a literature review to allocate impact scores to alien bird species with self-sustaining populations in Australia. These scores were then tested for correlation with a series of life history traits. The results were compared to data from a previous study in Europe, undertaken using the same methodology, in order to establish whether there are any life history traits consistently correlated with impact across both continents. Habitat generalism was the only life history trait found to be consistently correlated with impact in both Europe and Australia. This trait shows promise as a potential predictor of alien bird impacts. The results support the findings of previous studies in this field, and could be used to inform decisions regarding the prevention and management of future invasions.
Undesirable aliens: factors determining the distribution of three invasive bird species in Singapore
Journal of Tropical Ecology, 2003
Biological invasions are a major environmental concern due to their negative impacts on biodiversity and economics. We determined the population sizes and habitat-abundance relationships of the three most successful invasive bird species in Singapore: the house crow Corvus splendens, white-vented myna Acridotheres javanicus and common myna A. tristis. Estimated population sizes of the three species between February 2000 and February 2001 were between 106 000-176 000, 122 000-155 000 and 20 000-29 000, respectively. Population size of the house crow grew dramatically (>30-fold) in the last 15-16 y while that of the white-vented and common myna declined. Habitat-abundance relationships suggest that house crows are highly dependent on anthropogenic food. Their abundance was also positively related to proximity to coast. The common myna associated closely with agricultural areas while the white-vented myna probably preferred urban greenery among residential buildings. Our study shows...
The common myna (Acridotheres tristis) in urban Sydney and its surrounds
Emu, 2014
Common Myna (Sturnus tristis, formerly Acridotheres tristis) is one of Australia's most readily identified pest species and have been implicated in the reduction of native fauna. This study aimed to determine the distribution, habitat use and roost site selection of Mynas on the urban fringes of Sydney, New South Wales, Australia, as well as the avian species composition of areas in which Mynas occurred. The information was gathered with a view to estimating the impact of this invasive species on native avifauna. In total 3661 birds were counted in 1349 km of survey transects in western Sydney. Mynas were the most abundant bird recorded in the surveys, and exotic species accounted for 41% of all birds counted, but only 20% of the total number of species. Comparison of distribution data across habitat types suggests that Mynas do not extend far beyond urban habitats, and Mynas were primarily observed in suburban-industrial areas, small suburban reserves or sporting grounds and roadsides in semi-rural areas. Differences in sex-specific size distribution of Mynas occurred in semi-rural and urban areas. Urban areas also contained higher densities of preferred roosting trees with dense canopies, suggesting Myna populations have been aided by historical urban planning and landscaping. Together these data suggest that Mynas are likely to affect urban-dwelling native avifauna and that careful urban planning may reduce their distribution and potentially their impact.