The productivity of the macroinvertebrate prey of the platypus in the upper Shoalhaven River, New South Wales

2015 ◽  
Vol 66 (12) ◽  
pp. 1128 ◽  
Author(s):  
R. Marchant ◽  
T. R. Grant

The platypus (Ornithorhynchus anatinus) feeds almost exclusively on benthic macroinvertebrates, yet no attempt has been made to link its energy demands with the productivity of its benthic macroinvertebrate prey. In the upper Shoalhaven River, New South Wales, we estimated macroinvertebrate production (in 2009 and 2011) from benthic samples and recorded platypus diet (2009 only) from cheek pouch samples. Ephemeroptera, Trichoptera and Chironomidae were the most numerous of six major groups in both the cheek pouches and the benthic samples. Three other groups (Odonata, Coleoptera, Sphaeriidae) were much less abundant in the benthos, but Odonata were common in the cheek pouches. In both years the Ephemeroptera, Trichoptera and Chironomidae had levels of production that were an order of magnitude higher than those of the three other groups. Rank correlation indicated that the most productive taxa were those most likely to occur in the cheek pouches. Total macroinvertebrate production for the six groups varied from 7.8gDWm–2year–1 in 2009 to 13.1gDWm–2year–1 in 2011. Previous estimates of field metabolic demand of the platypus enabled calculation of the number that could be supported by a given level of production. The observed levels of production were sufficient to support 13–27 platypuses in 2009 and 22–45 in 2011 along a 1.5-km reach of the river. Despite considerable landscape change, productive foraging habitat persists in the upper Shoalhaven River.


1981 ◽  
Vol 32 (6) ◽  
pp. 967 ◽  
Author(s):  
RWJ Pidgeon

The diets and growth rates of rainbow trout in the Wollomombi and Guy Fawkes Rivers in northern New South Wales were examined. The growth rate of trout in the Wollomombi River was much higher than that of fish in the Guy Fawkes River. Spearman rank correlation coefficients indicated that stream type was more important than fish size in determining the composition of the diet of the trout. Benthic invertebrates formed the largest component of the diet in both streams: 66.0 and 63.0% of ash-free dry weight (AFDW) in the Wollomombi River and the Guy Fawkes River, respectively. Trout in the Wollomombi River consumed more nektonic prey (33.3% of AFDW) than fish in the Guy Fawkes River (3.7% of AFDW). In contrast, surface food (aquatic imagines and terrestrial insects) made up a much higher proportion of the diet of trout in the Guy Fawkes River (33.9% of AFDW) than in the Wollomombi River (0.6% of AFDW). Crayfish were a major component of the diet (in terms of AFDW) in both streams, their proportions increasing with fish size. The significance of crayfish in relation to fish growth is discussed.



1999 ◽  
Vol 21 (2) ◽  
pp. 177
Author(s):  
T.R. Grant ◽  
P.C. Gehrke ◽  
J.H. Harris ◽  
S. Hartley

Data from the New South Wales Rivers Survey on the occurrence of platypuses have provided the most recent and comprehensive record of platypus distribution in the State. The species was most commonly reported from the montane and coastal regions, being less common on the western slopes and uncommon in the rivers of the western lowlands. The observations confirmed those from earlier community-based surveys. In contrast to the distribution of native fish species, there appears to have been little change in the overall state-wide distribution of the platypus in response to degrading processes in the rivers of New South Wales, although nothing is known of the stability of their population numbers.



1983 ◽  
Vol 31 (4) ◽  
pp. 421 ◽  
Author(s):  
PJ Canfield ◽  
RJ Whittington

Blood was collected from the bill sinus of 10 healthy, mature platypuses captured in the Upper Shoalhaven River of New South Wales. Blood from all 10 animals was used for light microscopic morphometrical studies, and that from four of them was used for ultrastructural studies. The erythrocytes presented no unusual features and were similar to those described for other monotremes, marsupials and man. Platelets were of a mammalian type and uniform. Features of the leukocytes were compared and contrasted with those of other monotremes, marsupials, domestic mammals and man. Unusual features of the leukocytes of the platypus included the consistent presence of Dohle bodies within segmented neutrophils, and the nonsegmented nature of nuclei of eosinophils and basophils. Ultrastructural studies confirmed these findings.



1983 ◽  
Vol 31 (6) ◽  
pp. 881 ◽  
Author(s):  
TR Grant ◽  
M Griffiths ◽  
RMC Leckie

Female platypuses captured in waters of eastern New South Wales were found to be lactating between the months of October and March. Lactating females were most numerous in December, accounting for 64% of females captured. Non-lactating females were taken in all months, indicating that not all females breed successfully every year. There was no significant difference between the fatty acid complement of milk taken from a platypus lactating very late in the season and those of others sampled in December at the peak of the lactation season. Some evidence exists that females do not become reproductive until at least their second year of life. Some females were found lactating in consecutive years, and others lactated one year and not in the one following. Animals of over 9 years of age are known to breed. Most juveniles were captured in February, March and April, and it is suggested that the young leave the breeding burrows for the first time in late January through to March, and become independent from their mothers, who are ceasing lactation at that time.



1998 ◽  
Vol 20 (2) ◽  
pp. 251
Author(s):  
R.W. Turnbull

Distribution of the platypus (Ornithorhynchus anatinus) in the Bombala River catchment in south-eastern New South Wales was surveyed using questionnaires. Platypuses were reported from all streams in the catchment. The majority of positive sightings were from downstream areas whereas very few positive sightings were reported from headwater areas. The difference between frequencies of headwater and downstream reports of sightings was significant. The platypus was considered common throughout the catchment.



2006 ◽  
Vol 28 (1) ◽  
pp. 1 ◽  
Author(s):  
C. Turbill ◽  
M. Ellis

In south-eastern Australia, the greater long-eared bat (Nyctophilus timoriensis) has been rarely captured and is considered uncommon, although large areas within its range have received little survey effort. We collate existing capture records and present new data on N. timoriensis captures from recent fauna inventory surveys across the western slopes and plains of New South Wales (NSW). From 1628 trap nights at 39 study areas, 118 N. timoriensis were captured out of a total of 8266 bats. In larger remnants in the Brigalow Belt South Bioregion, N. timoriensis was captured at a rate of 0.1 to 0.6 per trap night and made up 7 to 9% of bat captures. This was approximately an order of magnitude greater than in other study areas throughout western NSW. There were no captures from the Darling Riverine Plains Bioregion. These surveys show that the large vegetation remnants of Goonoo, Pilliga West and Pilliga East study areas are a distinct stronghold in the distribution of the south-eastern form of N. timoriensis.



1995 ◽  
Vol 17 (1) ◽  
pp. 37 ◽  
Author(s):  
MH Campbell ◽  
AM Bowman ◽  
WD Bellotti ◽  
JJ Friend ◽  
HI Nicol

In four experiments near Walgett, New South Wales, between 1987 and 1990, the establishment and survival of Astrebla lappacea, Setaria incrassata, Panicurn coloraturn var. rnakarikariense and Cenchrus ciliaris were determined when surface-sown into low, reduced or heavy stubble just before or after harvesting wheat (November or December). Despite external deleterious factors affecting three experiments, grasses established in the first six months after sowing in all experiments unde; above average rainfall. Best establishment (8 to 31 plants/m2 in the 1990 experiment) occurred in response to 166 mm in 12 rain days over a 29 day period in December-January 1990-91, followed by 10 dry days and then a further 60 mm of rain in February; plants flowered by May and thus survived winter well. Under non-flood conditions (1987, 1988 and 1990 experiments) the order of magnitude of establishment was: C. ciliaris, A. lappacea > S. incrassata > P. coloraturn. Under flood conditions (1989 experiment) establishment of S. incrassata was highest and that of A. lappacca was lowest. In the 1987 and 1988 experiments full stubble (1.5 and 3.4 t/ha) did not improve the establishment of surface-sown grasses over that on low stubble (0.1 and 1.4 tlha). In the 1989 and 1990 experiments establishment was lower on full stubble (5 and 7 tlha) than on low stubble (0.1 and 0.1 tlha) owing to, respectively, flooding and competition from volunteer wheat. After the six months establishment period grass density declined over the two to five year survival period with plants self- thinning due to interspecific competition. Allowing mature plants to seed increased plant density due to seedling recruitment under favourable climatic conditions.



1998 ◽  
Vol 20 (2) ◽  
pp. 221
Author(s):  
T.R. Grant ◽  
P.O. Temple-Smith

Body lengths and bill dimensions were recorded from 26 nestling platypuses from various museum collections and from published records. In nestling platypuses less than 3 months old bill width was greater than length, but this was reversed in older nestlings and in juveniles of both sexes. Nestlings grew from a body length of approximately 5 cm (~ 1 week of age) to 34 cm (14-17 weeks). Comparative data on growth of captive nestlings while sparse, supported the general trends seen in nestlings collected for this study. Body lengths and weights were also recorded from 219 (113 female; 106 male) platypuses which had been captured initially as juveniles in the upper Shoalhaven River. New South Wales. Recaptures resulted in 358 separate (215 female; 143 male) records from these animals. At emergence from the breeding burrow in January/February, juvenile males were significantly larger than females. Juvenile males had a mean body length of 41.2 (S.D.± 2.8) and females 37.5 (S.D.± 2.0) cm respectively (p<O.OOI) and mean body weights of recently emerged juvenile males and females were 779 (S.D.± 127) and 588 (S.D.± 88) g (p<O.OOI). Mean lengths and weights of the emerged juveniles were significantly smaller (p<O.OOI) than those sampled as adults (weight 65-70%; length 83-87%). The wide variation in weights and lengths of juvenile individuals of both sexes at first capture may be due to different times of emergence and/or the effects of different litter sizes.



1998 ◽  
Vol 20 (2) ◽  
pp. 193
Author(s):  
C.H. Gallagher ◽  
J.R. Giles ◽  
E.M. Lonnon

In order to establish baseline data, plasma samples were collected from 139 platypuses in 12 New South Wales rivers seasonally during 1992-1996 for analysis of 23 biochemical parameters. Platypuses were caught in unweighted gill nets as described by Grant and Carrick (1974). The nets were kept under constant surveillance for trapped platypuses which were removed in 5-10 minutes, wrapped in damp, air-permeable bags and kept cool until processed within 30 minutes. Sex and approximate age were determined by spur morphology as described by Temple-Smith (1973). Body condition was assessed by the tail volume index, devised by Grant and Carrick (1978), and body weight and dimensions measured. A 1 ml of blood sample was collected from the upper biII sinus of each animal and stored on ice in a heparinised microtube until centrifuged to collect and freeze the plasma, which was analysed in the Department of Biochemistry, Royal Prince Alfred Hospital by the methods of Poulos and Piesse (1995) using an automatic multi analyser for assays other than fat soluble vitamins. Vitamins A and E were assayed by HPLC-UV Detector. Vitamin D was assayed by Radioimmuno-assay.



1998 ◽  
Vol 20 (2) ◽  
pp. 308
Author(s):  
M. Mcleod ◽  
D. Goldney

Platypuses, Ornithorhynchus anatinus, have been studied on the Duckmaloi River, New South Wales, in a long term mark-release-recapture project from 1986 to 1996. Some animals are recaptured regularly, while others are trapped only once. A high percentage of juveniles are never retrapped. New animals continue to be captured each year. Hence radio-tracking was employed to examine the movements of animals within the river system including their spatial utilisation of the Duckmaloi Weir. Concurrent studies on activity patterns and burrow usage were undertaken. Seventeen animals (I 0 juveniles, 2 subadults and 5 adults) were radio-tracked for various lengths of time between January and October 1993. Telemetric data revealed that radio-tagged animals were not recaptured on all possible occasions. Home ranges (length of river) varied from 0.5 km to 3.5 km. Home ranges of all animals, overlapped extensively, while core area overlap also occurred in the pool behind the Duckmaloi weir. One juvenile male dispersed 8.5 km upstream from the weir. Platypuses typically utilised areas when feeding with water depth between I to 2.5 m, rarely using areas less than 0.5 m deep. Juvenile platypuses were crepuscular and nocturnal, while adults, although mainly nocturnal also exhibited individual variations in diurnality. Although some individuals remained active throughout the night, others returned to burrows before re-entering the water. Animals commonly returned to certain burrow complexes with some exhibiting a higher degree of burrow site specificity than others. Certain burrows were used by nearly all radio-tagged animals over time while others were used by only a select number of individuals. Some animals tracked in the weir pool were found to share burrows.



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