2019 Aerial Survey of Wetland Birds in Eastern Australia
• The year 2019 has been exceptionally dry with significant rainfall deficiencies continuing to affect most of Australia. This years spring was the driest on record across Australia and the year-todate rainfall has been the lowest on record for southern Australia. The Murray–Darling Basin has experienced its worst 2-3 year drought period in over 120 years.
• Almost all of NSW is drought affected (42%) or in drought (57.7%), with a significant portion of the state (14%) experiencing intense drought (DPI 2019). More than 66% of Queensland is drought affected or in drought, across most of the Lake Eyre, Bulloo-Bancannia and Murray Darling river basins (Qld Dept. of Agriculture & Fisheries 2019). Rainfall was below to very much below average with most of eastern South Australia drought affected (Primary Industries and Regions SA 2019), and northern Victoria where drought conditions have intensified.
• As well as being extremely dry, 2019 has also been very warm. Australian maximum temperatures for the year to date have been the second warmest on record, second only to 2014. New South Wales has experienced its warmest January–November period on record, while Victoria had its hottest day on record (BOM 2019). Queensland temperatures were also well above average with the third warmest year on record (BOM 2019).
• All major indices for waterbirds (total abundance, breeding index, number of species breeding and wetland area index) continue show significant declines over time; If 1983 & 84 peak years are omitted then 3 of the 4 major indices show significant decline (OLS regression at p=0.05; variables 4th root or log transformed where appropriate; Fig. 1; Table 1). Long term trends are more informative for predicting population status than year to year fluctuations.
• Total waterbird abundance (n=208,364) increased marginally from 2018 but remains well below average: the 13th lowest in 37 years. Waterbirds were most abundant in bands 2 and 9 (Figs 1, 2 & 5).
• Breeding species’ richness and breeding abundance, increased compared to the previous year; however, breeding was heavily concentrated at one site – Rhyll Swamp in Band 1 (Fig. 6) and comprised mostly of Straw-necked ibis.
• Species functional response groups (feeding guilds) all showed significant long term declines (Fig. 3; Table 2). Long term changes were also observed in decadal averages of total abundance, wetland area index, breeding index and breeding species richness (Fig. 4).
• Wetland area index was the lowest since surveys began. Some rivers and wetlands in the northern Lake Eyre Basin including the Diamantina and Georgina rivers, held small amounts of water and supported low numbers of waterbirds. Lakes Torquinnie and Mumbleberry held water and supported moderate to high numbers of waterbirds. Lake Galilee was shallow and drying and supported the largest concentration with more than 43,000 waterbirds (Fig. 5).
• The Macquarie Marshes were very dry with very low numbers of waterbirds and no breeding. The Lowbidgee wetlands had little water, but with some low environmental flows provided by the NSW Government and Commonwealth managed environmental water, but were drier than in 2018; they supported low numbers of waterbirds with no breeding recorded. Most of the wetlands in the Menindee Lakes system were dry except the small Copi Hollow and a small amount of water remaining in Lake Wetherell. Overall, there were few waterbirds and no breeding activity. This was the driest that the system has been in 37 years. The Tallywalka lakes system was also dry (Fig. 7).
Claypan wetlands west of Cunnamulla
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