The abundance of native insects on the introduced weed Mimosa pigra in Northern Australia

1990 ◽  
Vol 6 (2) ◽  
pp. 219-230 ◽  
Author(s):  
G. J. Flanagan ◽  
C. G. Wilson ◽  
J. D. Gillett
Keyword(s):  
Central America ◽  
Northern Territory ◽  
Biocontrol Agents ◽  
Phytophagous Insect ◽  
Northern Australia ◽  
Insect Community ◽  
Wet Season ◽  
Mimosa Pigra ◽  
Monospecific Stand ◽  
Total Community

ABSTRACTA monospecific stand of the alien shrub Mimosa pigra (Mimosaceae) was examined weekly for 14 months from March 1984. A total of 44 phytophagous insect species were found on M. pigra. The five most abundant of these made up 74% of the total community. This insect community in general showed a distinct seasonal cycle of abundance with maximum numbers during the wet season. However, a few species had a completely different pattern.Two species, Mictis profana (Hemiptera: Coreidae) and Platymopsis humeralis (Coleoptera: Cerambycidae), were observed to cause substantial damage to M. pigra. When compared with the fauna of M. pigra from its native region, Central America, that of the Northern Territory is low in leaf and flower-feeding insects. It is suggested that these types of insects be sought as future biocontrol agents to complement those native insects causing damage and those biocontrol agents already released.

Feral Pig (Sus Scrofa) Rooting in a Monsoon Forest-Wetland Transition, Northern Australia.

1991 ◽  
Vol 18 (6) ◽  
pp. 761 ◽  
Author(s):  
DMJS Bowman ◽  
L Mcdonough
Keyword(s):  
Sus Scrofa ◽  
Ground Cover ◽  
Northern Territory ◽  
Northern Australia ◽  
Wet Season ◽  
Monsoon Forest ◽  
Dry Seasons ◽  
Set Up ◽  
Seasonally Flooded ◽  
Wet And Dry Seasons

A grid of 447 cells (each 50x50 m) was set up in a wet monsoon rain forest on a gradual slope above the Adelaide River floodplain in the Australian Northern Territory. Surveys of pig (Sus scrofa) rooting were carried out at approximately 3-month intervals from November 1988 to September 1989. The pigs had only limited effects on the forest in both the wet and dry seasons. The seasonally flooded swamp communities (Melaleuca forest and sedgeland) were primarily exploited in the dry season; dryland communities ([Eucalyptus] and Lophostemon forests) were exploited during the wet season. Rainfall during the previous wet season may have influenced the pattern of rooting in the dryland forests. Rooting and ground cover were weakly positively related in 3 out of the 4 surveys.

scholarly journals PREHISTORIC ARCHAEOLOGY IN NORTHERN AUSTRALIA

1986 ◽  
Vol 7 (2) ◽  
pp. 1-3
Author(s):  
Harry Allen
Keyword(s):  
Fresh Water ◽  
Coastal Plain ◽  
Northern Territory ◽  
Northern Australia ◽  
Prehistoric Archaeology ◽  
Wet Season ◽  
Mountain Area ◽  
Plain Area ◽  
The North ◽  
North Western

The northern part of North Australia is not far from Java and Timor. There are great numbers of influences in the North Western part of Australia from Indonesian region. The coast alligator river area is 200 kilometres east of Darwin, Northern Territory is now 60 kilometres from the coast to the mountain area. The plain area is flat and the water is salty, being tidal on the coast. Further inland the river is fresh water. To day there are few mangroves in this area, but there is evidence that mangroves were more widespread between 6.000 - 3.000 BP. During the wet season the coastal plain is flooded.

The Foods and Feeding Habits of Subadult Crocodylus Porosus Schneider in Northern Australia.

1979 ◽  
Vol 6 (3) ◽  
pp. 347 ◽  
Author(s):  
JA Taylor
Keyword(s):  
Feeding Habits ◽  
Stomach Contents ◽  
Northern Territory ◽  
Northern Australia ◽  
Wet Season ◽  
Flood Plains ◽  
Significant Difference ◽  
Arnhem Land ◽  
Crocodylus Porosus ◽  
Slow Moving

Stomach contents were studied for 289 live young crocodiles (Crocodylus porosus) less than 180 cm long, collected from coast, river and swamp of Arnhem Land, Melville Island and Grant Island, Northern Territory, Australia; the crocodiles were then released. Tables give orders and families and some generic and specific names for prey or carrion eaten and for 3 parasites on the crocodiles, for a dry and a wet season in 1975-76. Between crocodiles 50 to 120 cm long and those smaller or larger there was no significant difference in the proportion of crocodiles having eaten crabs, shrimps, fish or insects or with empty stomachs, but only the larger crocodiles ate mammals or birds. Frequency of different foods eaten differed significantly with type of habitat or with salinity. Weight of food or incidence of empty stomachs did not differ between seasons, habitats or salinities. Condition of the crocodiles was significantly poorer for those from freshwater swamps than for those from lower mangrove or flood plains, and highest for those from upper mangrove. Main foods in both seasons were crustaceans, mainly crabs of subfamily Sesarminae and shrimps of genus Macrobrachium. The only fish eaten regularly was Pseudogobius sp., a slow-moving fish found by the water's edge. Amphibians were not found in the stomach.

Targeted sampling successfully detects the cryptic and declining arboreal marsupial (Phascogale pirata) in northern Australia

2020 ◽  
Vol 26 (4) ◽  
pp. 395
Author(s):  
Hayley M. Geyle ◽  
Leigh-Ann Woolley ◽  
Hugh F. Davies ◽  
John C. Z. Woinarski ◽  
Brett P. Murphy
Keyword(s):  
Conservation Status ◽  
Study Finding ◽  
Northern Territory ◽  
Northern Australia ◽  
Wet Season ◽  
Breast Height ◽  
Nest Boxes ◽  
Targeted Sampling ◽  
Large Trees ◽  
Survey Effort

The threatened northern brush-tailed phascogale (Phascogale pirata) is one of the most poorly known mammals in Australia. While the few available records indicate a decline in its distribution and abundance, it has not previously been subject to intensive targeted survey. Here, we trialled a specifically tailored methodology for detection of P. pirata, with the aim of informing ongoing survey and monitoring of this species. We deployed 50 motion-sensor cameras (spaced closely together in a grid 500×1000m) on Melville Island (Northern Territory, Australia), between June 2018 and May 2019. Cameras were baited and secured to trees ~3m above the ground on a bracket facing the trunk. We selected for large (>30cm diameter at breast height [DBH]) trunks of the dominant tree species (Eucalyptus miniata, E. tetrodonta and Corymbia nesophila). We detected P. pirata 16 times on eight cameras over the duration of the study, finding that detection was most likely on large (DBH >41.5cm) E. tetrodonta trees during the wet season. Our results indicate that survey effort for this species should be seasonally targeted and focussed on large trees. However, the efficacy of additional methods (nest boxes, Elliott traps) and a comparison between detections on arboreal versus ground-based cameras requires further investigation. We highlight the importance of conducting additional work on this species, as little is known about its ecology, population trends and threats, making it difficult to assess its conservation status. Without more targeted work, P. pirata is at risk of slipping into extinction unnoticed.

Composition, leaf area index and standing biomass of eucalypt open forests near Darwin in the Northern Territory, Australia

2000 ◽  
Vol 48 (5) ◽  
pp. 629 ◽  
Author(s):  
A. P. O'Grady ◽  
X. Chen ◽  
D. Eamus ◽  
L. B. Hutley
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Carbon Balance ◽  
Stand Structure ◽  
Northern Territory ◽  
Northern Australia ◽  
Wet Season ◽  
Area Index ◽  
Standing Biomass ◽  
Open Forests

Savanna communities dominate the wet–dry tropical regions of the world and are an important community type in monsoonal northern Australia. As such they have a significant impact on the water and carbon balance of this region. Above the 1200-mm isohyet, savanna’s are dominated by Eucalyptus miniata–E. tetrodonta open forests. We have described in detail the composition and structure as well as seasonal patterns of leaf area index and above-ground biomass in the E. miniata–E. tetrodonta open forests of the Gunn Point region near Darwin in the Northern Territory of Australia. In all, 29 tree species from four phenological guilds were recorded in these forests. Stand structure suggests that the forests were still recovering from the impacts of cyclone Tracy and subsequent frequent fires. Eucalyptus miniata and E. tetrodonta were significant contributors to overstorey leaf area index and standing biomass (>70%), and both leaf area index and biomass were strongly correlated to basal area. Leaf area index was at a maximum (about 1.0) at the end of the wet season and declined over the dry season by about 30–40%. There were proportionally greater changes in the understorey reflecting the greater contribution of deciduous and semi-deciduous species in this strata. Standing biomass was about 55 t ha –1 . Detailed descriptions of leaf area index and biomass are important inputs into the development of a water and carbon balance for the savanna’s of northern Australia.

scholarly journals Causes of the decline of the Gouldian Finch Erythrura gouldiae

1996 ◽  
Vol 6 (1) ◽  
pp. 49-61 ◽  
Author(s):  
Sonia C. Tidemann
Keyword(s):  
Clutch Size ◽  
Nest Site ◽  
Northern Territory ◽  
Dry Season ◽  
Northern Australia ◽  
Wet Season ◽  
Breeding Sites ◽  
Low Intensity ◽  
Tree Hollows ◽  
Gouldian Finch

SummaryPopulations of Gouldian Finch Erythrura gouldiae, an estrildid endemic to northern Australia, declined markedly during the last two or three decades. A survey revealed the species in two areas of Northern Territory, with an estimated 2,000 individuals, including juveniles. Recaptures were low either because of mortality or dispersal. Gouldian Finches eat predominantly Sorghum spp. seeds, but consume other seeds before Sorghum ripens. Other finches declined as cattle increased. Gouldian Finches breed in tree hollows of predominantly two species of eucalypts that grow on rocky slopes. They require water within about 4 km of the nest site. There was no shortage of nesting hollows at the known breeding sites. Fires in the early to mid-dry season allow birds access to seed without damaging trees, but later fires can destroy trees with nest hollows and remove shade. Average clutch-size is 5.2. About 72% of eggs laid, and 63% of nests, fledged young. Pairs lay up to three clutches in a season (February-August), the length of which may depend on rainfall during the preceding wet season. Air-sac mite (Sternostoma tracheacolum), found in 62% of Gouldian Finches sampled, may be preventing the species recovering to former numbers. New colonies of Gouldian Finches should be identified, populations monitored, and habitat managed by effecting patchy burns by low-intensity fires early in the dry season.

A comparison of once- and twice-yearly weaning of an extensive herd in northern Australia

1997 ◽  
Vol 37 (3) ◽  
pp. 279 ◽  
Author(s):  
R. M. Sullivan ◽  
P. K. O'Rourke
Keyword(s):  
Bos Taurus ◽  
Bos Indicus ◽  
Mortality Rates ◽  
Northern Territory ◽  
Northern Australia ◽  
Wet Season ◽  
Increased Risk ◽  
Native Pastures ◽  
Reproductive Rates ◽  
Poor Nutrition

Summary. In northern Australia, many cows conceive only after their calves are weaned. The subsequent calves are born in the late wet or early dry season. Where producers wean once a year these late calves stay with the cows with resultant increased risk of cow mortality. A second weaning may reduce this risk. From June 1985 to June 1990 we recorded cow liveweights, mortalities and reproductive rates from a herd of 500 Bos indicus-Bos taurus-cross cows at Kidman Springs, Northern Territory. The herd grazed native pastures, and was continuously mated and unsupplemented. Calves were weaned if they weighed 100 kg or more at muster in June (W1) or in either of June and October (W2). In both groups (W1 and W2), 75% of calves were weaned at the June muster, and a further 14% were weaned at the October muster (W2 group). There was no difference in liveweight change, mortality or branding rates between the 2 groups. Overall productivity was low, probably due to poor nutrition during both dry and wet seasons. For example, average branding and mortality rates were 51.8 and 11.8%. Forty-seven percent of all cows were pregnant at the June muster but a quarter of these failed to rear a calf. The low proportion of calves suitable for weaning in October indicated that the weaning times were too close together, and did not allow enough late calves to reach the target liveweight for weaning. Consequently, the benefit of the second weaning was reduced. Weaning times for continuously mated herds should be determined by the time taken for calves born late in the wet season to reach target liveweights for weaning at the second weaning round. Effectively, this means the first weaning should be earlier, perhaps in April, since high temperatures and the increased likelihood of rain make mustering after October difficult.

Problem crocodiles, Crocodylus porosus, at Nhulunbuy, Northern Territory: an assessment of relocation as a mangaement strategy

1993 ◽  
Vol 20 (1) ◽  
pp. 127 ◽  
Author(s):  
B Walsh ◽  
PJ Whitehead
Keyword(s):  
Carrying Capacity ◽  
Northern Territory ◽  
Effective Strategy ◽  
Wet Season ◽  
Rates Of Return ◽  
Saltwater Crocodile ◽  
Crocodylus Porosus ◽  
Remote Sites ◽  
Total Capture ◽  
Capture Rates

Since 1986 the Conservation Commission of the Northern Territory has operated a programme to remove 'problem' saltwater crocodiles from waters in and adjoining the township of Nhulunbuy. Over a period of five years, 52 different saltwater crocodiles (44 male) were captured. Most (48) were released at remote sites designated by the traditional Aboriginal owners of the surrounding lands. Release distances from the township varied from 17 to 282 km (by coastline). Many crocodiles (47.9%), including those released at the most distant sites, returned to, and were subsequently recaptured at, the township. Total capture rates (initial captures and recaptures pooled) varied seasonally, with fewer crocodiles being caught in the cooler dry season. During the wet season capture rates remained high, but relatively fewer 'new' crocodiles were caught. Probability of recapture could not be related to distance and direction of release from the township, nor size and sex of the released crocodile. Frequency of capture of individual crocodiles (1-8 times) was also unrelated to these variables. The high rates of return indicate that relocation is unlikely to be an effective strategy for managing humancrocodile interactions, at least in areas where potential release sites already support saltwater crocodile populations near carrying capacity.

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