The influence of annual rainfall upon capture rates of a nectar-dependent marsupial

1998 ◽  
Vol 25 (2) ◽  
pp. 165 ◽  
Author(s):  
R. D. Wooller ◽  
K. C. Richardson ◽  
C. A. M. Garavanta ◽  
V. M. Saffer ◽  
C. Anthony ◽  
...  

The capture rates of honey possums, Tarsipes rostratus, on the south coast of Western Australia were significantly related to annual rainfall in the preceding year. It is suggested that numbers of the short-lived and aseasonally breeding honey possum fluctuate in relation to nectar levels, which vary with cumulative water availability.

2014 ◽  
Vol 18 (9) ◽  
pp. 3591-3614 ◽  
Author(s):  
S. A. Islam ◽  
M. A. Bari ◽  
A. H. M. F. Anwar

Abstract. Reduction of rainfall and runoff in recent years across southwest Western Australia (SWWA) has attracted attention to the climate change impact on water resources and water availability in this region. In this paper, the hydrologic impact of climate change on the Murray–Hotham catchment in SWWA has been investigated using a multi-model ensemble approach through projection of rainfall and runoff for the periods mid (2046–2065) and late (2081–2100) this century. The Land Use Change Incorporated Catchment (LUCICAT) model was used for hydrologic modelling. Model calibration was performed using (5 km) grid rainfall data from the Australian Water Availability Project (AWAP). Downscaled and bias-corrected rainfall data from 11 general circulation models (GCMs) for Intergovernmental Panel on Climate Change (IPCC) emission scenarios A2 and B1 was used in LUCICAT model to derive rainfall and runoff scenarios for 2046–2065 (mid this century) and 2081–2100 (late this century). The results of the climate scenarios were compared with observed past (1961–1980) climate. The mean annual rainfall averaged over the catchment during recent time (1981–2000) was reduced by 2.3% with respect to the observed past (1961–1980) and the resulting runoff reduction was found to be 14%. Compared to the past, the mean annual rainfall reductions, averaged over 11 ensembles and over the period for the catchment for A2 scenario are 13.6 and 23.6% for mid and late this century respectively while the corresponding runoff reductions are 36 and 74%. For B1 scenario, the rainfall reductions were 11.9 and 11.6% for mid and late this century and the corresponding runoff reductions were 31 and 38%. Spatial distribution of rainfall and runoff changes showed that the rate of changes were higher in high rainfall areas compared to low rainfall areas. Temporal distribution of rainfall and runoff indicate that high rainfall events in the catchment reduced significantly and further reductions are projected, resulting in significant runoff reductions. A catchment scenario map has been developed by plotting decadal runoff reduction against corresponding rainfall reduction at four gauging stations for the observed and projected periods. This could be useful for planning future water resources in the catchment. Projection of rainfall and runoff made based on the GCMs varied significantly for the time periods and emission scenarios. Hence, the considerable uncertainty involved in this study though ensemble mean was used to explain the findings.


Lithos ◽  
1978 ◽  
Vol 11 (3) ◽  
pp. 209-218 ◽  
Author(s):  
N.C.N. Stephenson ◽  
H.D. Hensel

1997 ◽  
Vol 48 (1) ◽  
pp. 49 ◽  
Author(s):  
W. K. Anderson ◽  
G. B. Crosbie ◽  
W. J. Lambe

Wheat cultivars acceptable for the Noodle wheat segregation in Western Australia were compared with cultivars suitable for the Australian Standard White (ASW) grade over the period 1989–93. Yield and grain quality responses to sowing time, nitrogen fertiliser, soil type, and cropping history were examined to determine management practices most likely to result in wheat grain suitable for the production of white, salted noodles. Thirty experiments were conducted in the 300–450 mm average annual rainfall zone between Three Springs in the north (approx. 29° 30′S) and Newdegate in the south (approx. 33°10′S). The ASW cultivars, Spear, Kulin, and Reeves, outyielded the Noodle cultivars, Gamenya and Eradu, by 8–10% on average, but the yield difference was less at later sowings. The optimum sowing time was early May for most cultivars. The new cultivars, Cadoux (Noodle) and Tammin (potential Noodle, but classiffied General Purpose), tested in 1992 and 1993 in 12 experiments showed an optimum sowing time of late May, as did other midseason cultivars. Grain yields of May-sown crops were increased by 13 kg for every 1 kg of nitrogen applied, compared with 3 : 1 for June-sown crops. Previous legume history of the site and grass weed control in the crop also influenced the grain protein percentage. It was concluded that adoption of production guidelines that include sowing at, or near, the break of the season with about 40 kg/ha of nitrogen fertiliser, a rotation that includes 2-3 years of legume crop or pasture in the previous 5 years, and adequate grass weed control will result in an excellent chance (>80%) of producing grain proteins within the receival standards for the Noodle grade. Flour swelling volume (FSV), an indicator of noodle eating quality, was negatively correlated (not always significantly at P = 0·05) with grain protein percentage in 7 out of 8 experiments. FSV values were larger from sites located in the south of the study area and this appeared to be independent of protein and time-of-sowing effects. Small grain sievings (<2 mm) were increased by sowing after the end of May, especially in the longer season cultivars.


2007 ◽  
Vol 29 (1) ◽  
pp. 25 ◽  
Author(s):  
S.D. Bradshaw ◽  
R.D. Phillips ◽  
S. Tomlinson ◽  
R. J. Holley ◽  
S. Jennings ◽  
...  

The Honey possum, Tarsipes rostratus, is an obligate nectarivore, known to feed on plant species from only three Families in south-western Western Australia: Myrtaceae, Proteaceae and Epacridaceae. These plants can be adversely affected by fire, decreased rainfall or groundwater levels and the pathogen Phytophthora cinnamomi. We investigated the ecology of T. rostratus in terms of: (i) how the population fluctuated in response to rainfall and fire over a 20-year period and (ii) changes in diet and movements during a period of decreased food availability in late summer. Mean capture rates were significantly positively correlated with mean flowering rates of Banksia ilicifolia over a 20-year period. Winter capture rates were also significantly positively correlated with both annual and winter rainfall two years prior to trapping in recently burnt areas, but not in long unburnt� areas. Capture rates were significantly higher in unburnt Banksia woodland during winter but densities there have declined since 1996, associated with the death of many Banksia ilicifolia trees from persistent Phytophthora infection. Notwithstanding this decline, winter capture rates in the unburnt areas were still approximately double those in the burnt areas 6 years after the last fire. Short-term capture rates were negatively correlated with barometric pressure, showing that movement and foraging is stimulated by the passage of low pressure frontal weather systems. Despite the paucity of known food sources flowering in late summer and autumn, there was no evidence of T. rostratus using plant species from other than the three above-noted Families. Utilisation areas in summer were also no larger than those previously recorded across all seasons in Scott National Park. Some individuals, however, moved extensive distances to locate spatially restricted food sources. The conservatism of their diet and the sensitivity of the population to changes in rainfall and fire history indicate that T. rostratus populations are particularly vulnerable to some of the environmental changes now occurring in south-western Australia.


2020 ◽  
Vol 71 (2) ◽  
pp. 128 ◽  
Author(s):  
Timothy T. Scanlon ◽  
Greg Doncon

The shift in Indian Ocean sea surface temperatures in 1976 led to a change in rainfall for the broad-scale winter annual grain cropping and pasture region in the south-west of Western Australia (the WA wheatbelt). Agriculture in the eastern part the WA wheatbelt was particularly sensitive to the change in rainfall because it is a marginal area for agronomic production, with low rainfall before changes in sea surface temperature. A second shift in sea surface temperature occurred in 2000, but there has been no analysis of the resulting impact on rainfall in the eastern WA wheatbelt. An analysis of rainfall pre- and post-2000 was performed for sites in the eastern WA wheatbelt in three groups: 19 sites in the west, 56 central, and 10 east. The analysis found a decline in growing-season rainfall (i.e. April–October), especially during May–July, post-2000. Rainfall declines of 49.9 mm (west group), 39.1 mm (central group) and 28.0 mm (east group) represented respective losses of 20.1%, 17.4% and 14.2% of growing-season rainfall. Increases in out-of-season rainfall in the respective groups of 31.0, 33.6, and 50.7 mm (57.8%, 60.8% and 87.6%) meant that annual rainfall changes were smaller than growing-season losses. The west and central groups lost 17.5 and 6.16 mm annual rainfall, whereas the east group gained 15.6 mm. Analysis of wheat yield indicated reductions of 13.5% (west) and 9.90% (central) in the eastern WA wheatbelt; the small group of east sites had a potential yield gain of 8.9% arising from the increased out-of-season rainfall. Further, increased out-of-season rainfall will exacerbate weed and disease growth over the summer fallow.


Sign in / Sign up

Export Citation Format

Share Document