Electronic Supplemental Material Online Resource 1 Field locations and field methods




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Electronic Supplemental Material

Online Resource 1

Field locations and field methods

Study districts

The study region was the woodland belt of eastern Australia, from western Victoria to central Queensland (Fig. 1, main text). Within this region, 350 sites were located within seven study districts. The climate ranges from subtropical to temperate, and the average annual rainfall is between 409 mm (Dimboola, Wimmera district) and 630 mm (Injune, Carnarvon district). The dominant woodland types were: buloke Allocasuarina luehmannii (Wimmera, 31 sites); Eucalyptus spp. (Victorian box-ironbark, 38 sites; Carnarvons, 75 sites); brigalow Acacia harpophylla (Moree, 35 sites; Tara, 84 sites; Dalby/Chinchilla, 48 sites); and white cypress pine Callitris glaucophylla and spotted gum Corymbia citriodora (Barakula, 40 sites). We use data from just these regions because we were confident of the consistency of the methods of data collection, but there is evidence of effects of the noisy miner on the woodland avifaunas in at least another 25 different areas within eastern Australia, including central and southern New South Wales and north-eastern Victoria (the area between districts 2 and 5 in Fig. 1) .



Bird surveys

These were conducted during the morning and late afternoon in one 2-ha (200 m  100 m) plot at each site. Between three and nine repeat 20-min surveys were conducted depending on the study district. Birds flying above the canopy were included if they appeared to be using the habitat of the plot (e.g. aerial foraging, e.g. tree martin Petrochelidon nigricans). All sites were open woodlands with low foliage cover, so that visual identifications dominated the data and there are few problems with detection . Data were excluded for: (1) water birds, and (2) any species occurring in fewer than five sites across the region. The latter cut-off is arbitrary, but we tested other values (< 7, <10 sites) with little effect on inferences . Four exotic species were recorded, but none was found in more than 6% of sites: (1) common myna Acridotheres tristis (15 sites); common starling Sturnus vulgaris (23 sites); (3) house sparrow Passer domesticus (18 sites); (4) European greenfinch Carduelis chloris (1 site); data for exotic species were elided from the data set.



Online Resource 2

Model fits for the range of candidate single-threshold densities

Profile of model fits (BPIC) for a range of one-threshold candidate threshold densities of noisy miners. Note the ordinate is scaled by a factor of 104.





Online Resource 3

Model fits for the range of candidate two-threshold densities

Contour plot of model fits for a range of two-threshold candidate threshold densities of noisy miners. The ‘reddest’ zones have the lowest BPIC scores and hence are the best fits.




References

Mac Nally R, Bowen M, Howes A, McAlpine CA, Maron M (2012) Despotic, high-impact species and sub-continental scale control of avian assemblage structure. Ecology 93:668-678



Maron M, A. Main A, Bowen A, Howes A, Kath J, Pillette C, McAlpine C (2011) Relative influence of habitat modification and interspecific competition on woodland bird assemblages in eastern Australia. Emu 111:40-51




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