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Project summary:
This is the bird-monitoring component of the FT “icon” project: Mount Weld Altitudinal Transect Ecotonal and Baseline Altitudinal Monitoring Plots (BAMPs), which is itself a long term ecological research program monitoring distributional change in vegetation and fauna along an altitudinal gradient on Mount Weld.
The number of bird species recorded during the surveys in the first two years was lower than that found in other similar studies elsewhere in Tasmania. This may be due to the restricted period of sampling and the relative habitat homogeneity of the study site. Twenty-four species were recorded, including eight endemic and one exotic species. Species richness and abundance both declined dramatically above the tree-line, about 1000 m. Only one species, typical of lowland treeless habitats elsewhere, was recorded solely above the tree-line in the initial surveys. Several species were restricted to mixed forest plots below 700 m above sea-level. Neither species richness nor abundance was significantly different between the two sampling periods. However, several species showed seasonal trends in abundance, as a result of movements into and out of the area or due to altitudinal movements within the area.
These baseline data will be available for comparison with data collected in future decades and as such may provide interesting information in the advent of significant climate change, particularly its effects on the higher altitude zones. These are the other bird projects undertaken at Warra: WRA034 Birds and wet eucalypt forest succession. WRA046 Bird succession in the Warra SST.WRA104 Development and implementation of standardised bird surveys in wet eucalypt forest at Warra.
Methodology: Fixed-point distance surveys of 20 minutes duration were conducted at 100 m contour intervals along three altitudinal transects. Each transect ran generally along a ridgeline in unlogged vegetation. The first ranged from 60 to 560 m asl and the second from 100 to 600 m asl. Both of these were in State forest. The third ranged from 600 to 1300 m asl on the slopes of Mt Weld in the Southwest National Park, part of the Tasmanian Wilderness World Heritage Area. All birds seen or heard were recorded, as well as the distance from the central point. To avoid problems arising from differences in species’ detectability, only those birds within 40 m were included for species richness and abundance analysis. Records beyond 40 m helped to inform species’ altitudinal distributions. The author performed all surveys on the lower transects, while the author and one other person performed the surveys on the upper transect.
Surveys were undertaken in late autumn and winter (between April 26th and June 6th 2000) and in summer (between January 9th and February 4th 2001). Plots on the upper transect were surveyed from seven to nine times in both sample periods. Plots on the lower transects were surveyed three times in autumn/winter, and four times in summer. At each plot, at least one survey in each season was performed in early morning (within three hours of sunrise). Other surveys were conducted in late morning and early afternoon, with exact times dependent on practical considerations of walking between sites. However, every effort was made to ensure that sample times were generally equivalent between sites. Surveys were not performed in rain or in high winds. There was no snowfall or snow cover during either of the sampling periods.
Seasonal differences in species richness and total abundance, as well as abundance of more common species (over all sites) were tested using the Mann-Whitney W test. Depending on these seasonal differences, species were classified as summer visitors, winter visitors and residents, while infrequently recorded species were not classified.
Datasets: None available.
Publications: Grove, S.J. (2004). Warra – Mount Weld altitudinal transect ecotonal and baseline altitudinal monitoring plots (BAMPs): establishment report. Technical Report no 17/2004. Forestry Tasmania, Hobart.
MacDonald, M. (2001). Altitudinal distribution of birds at the Warra LTER Site, southern Tasmania: a preliminary study. Tasforests 13: 87-100.
Powledge, F. (2002). A look back at the International Biodiversity Observation Year. BioScience 52: 1070-1079.
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