NT Naturalist - Number 27, Published October 2016
ISSN: ISSN 0155-4093
Editor: Richard Willan
Pre-release Articles
| Download | 1. New insights into Holocene economies and environments of Central East Timor: Analysis of the molluscan assemblage at the rockshelter site of Hatu Sour |
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| Authors | Brockwell, Sally; O’Connor, Sue; Litster, Mirani and Willan, Richard C. |
| Abstract | In the central region of East Timor (the proper name for this nation being Timor- Leste) little is known of prehistoric economies beyond 2000 years ago, most previous archaeological studies having been concentrated around the Baucau plateau and eastern end of the island. The village of Laleia on the Laleia River is located 20 km east of the main district town of Manatuto on the central northern coast. Recent excavations at the nearby rockshelter site of Hatu Sour have revealed a deep archaeological sequence that dates from approx. 11,000 years ago until the recent past. This paper examines the shellfish (i.e., molluscan) assemblage from the excavation at Hatu Sour for what it can reveal about prehistoric economies and the environment of this strategic region throughout the Holocene. |
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| Download | 2. The pathogen Myrtle Rust (Puccinia psidii) in the Northern Territory: First detection, new host and potential impacts |
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| Authors | Westaway, John O. |
| Abstract | The plant pathogenic fungus Myrtle Rust (Puccinia psidii) was detected within the Northern Territory on Melville Island in May 2015, five years after its arrival in New South Wales. In July the rust was found on mainland Northern Territory on the outskirts of Darwin and in September in the Darwin suburbs. Four myrtaceous plant species were found infected by the rust including the indigenous shrub Lithomyrtus retusa, which represents a novel host for P. psidii. The mode of arrival and the ecological implications of the spread of Myrtle Rust infection across Top End vegetation and plant industries are discussed. |
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| Download | 3. Asystasia gangetica subsp. micrantha, a new record of an exotic plant in the Northern Territory |
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| Authors | Westaway, John O; Alford, Lesley; Chandler, Greg; and Schmid, Michael |
| Abstract | An herbaceous weed of the acanthus family, Asystasia gangetica subspecies micrantha, sometimes known as Chinese Violet, was found naturalised in Darwin in April 2015 and was immediately eradicated. Although cultivated as an ornamental, this plant is regarded as an invasive weed in eastern Australia where it has been established for 15 years, and is a recognised problem weed in neighbouring tropical countries. Identification and taxonomic aspects of this species are briefly discussed, as is its distribution in Australia and overseas, and its possible means of arrival in Darwin. |
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| Download | 4. Seed viability of native grasses is important when revegetating native wildlife habitat |
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| Authors | Bellairs,, Sean M. and Caswell, Melina J. |
| Abstract | Native grasses are a dynamic and essential component of the majority of terrestrial ecosystems in the Northern Territory. Restoring native grasses in disturbed environments is important for providing faunal habitat, reducing surface erosion and resisting weed invasion. However, establishing native grasses has been problematic in many regions of Australia due to seed viability issues. We investigated 48 seed lots of 29 Northern Territory native grass species to determine whether seed quality was an issue for establishment of tropical native grasses. Seed lots were largely collected by commercial seed suppliers, rather than by research staff, so the samples reflect seed lots that could be sourced for revegetation projects. The seed purity, proportions of filled seeds, visually viable seeds and metabolically active seeds were assessed. Viability responses to storage were investigated in 15 seed lots. The proportion of florets that contained a seed (caryopsis) ranged from 10–97% (average 62%) and between 0–79% of the floretscontained metabolically active seeds (average 36%). Two seed lots had viability of 0–10% and 12 of the 48 seed lots had less than 30% seeds that were metabolically active and potentially viable. Thus, seed quality limits establishment of tropical native grasses from sown seeds in the Northern Territory. When using native grasses to establish native habitat it is important to assess the quality of the seeds and use a sufficient quantity of seeds for effective establishment of these grasses. Seeds of many species will maintain viability for several years if stored in cool dry conditions. Seed for revegetation projects can therefore be collected and stored over several years. |
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| Download | 5. Nest site fidelity of Flatback Turtles (Natator depressus) on Bare Sand Island, Northern Territory, Australia |
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| Authors | Bannister, Natalie; Holland, John and Farrelly, Trisia |
| Abstract | The endangered Flatback Turtle (Natator depressus) is endemic to the continental shelf of northern Australia and is the only species of marine turtle with such a restricted geographical distribution. Most mature female Flatback Turtles show a high degree of fidelity to their chosen nesting beach, returning to the same beach within the same and successive nesting seasons. Natal homing has been well studied in other species of marine turtles and our findings support the supposition that all marine turtles display a similar degree of natal homing. Our study area is Bare Sand Island, Northern Territory, where we investigated nest site fidelity of female Flatback Turtles and the influence of wind speed, air and sand temperature, and relative humidity on nest site selection. The data were collected during a 46-day period from 12 June 2012. On Bare Sand Island, female Flatback Turtles demonstrate very strong nest site fidelity, with consecutive nests being located 247 m ± 198 s.d. apart. During the peak 2012 breeding season, sand temperatures, wind speed and relative humidity remained constant, however there was a significant difference in the air temperature between nesting days. Our study of the effects of environmental factors on the nesting environment of Flatback Turtles will contribute towards management practices to protect this endangered species. |
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| Download | 6. Records of waterbirds and other water-associated birds from the 2014/15 migratory season in the Darwin region |
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| Authors | Lilleyman, Amanda |
| Abstract | Records of waterbirds, waterfowl, terns, gulls, egrets and herons, raptors, and resident shorebirds in the Darwin region, Northern Territory, were collected during fortnightly migratory shorebird monitoring. Eight study sites were monitored from August 2014 through to April 2015, which is considered the migratory season for most non-passerine birds in the Top End. Species abundance across the sites, breeding records, and new information on habitat use at an artificial habitat (East Arm Wharf) are presented. Across the eight study sites there were 39 species recorded, representing 15 taxonomic families. |
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| Download | 7. Fluctuations in use of urban roost and foraging sites in Darwin by Pied Herons (Ardea picata) |
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| Authors | Rawsthorne, John |
| Abstract | Pied Herons (Ardea picata) are a common bird of Australia’s north, strongly associated with shallow freshwater wetland and estuarine habitats. However they also use urban sites for foraging, and in particular many feed at the Leanyer Sewage Treatment Works and the Shoal Bay Waste Depot site in Darwin’s northern suburbs. Pied Herons roosted on Catalina Island in Darwin Harbour from at least 2010 to 2013. Seasonal fluctuations in numbers and use of that, and nearby roost sites, are documented here, as is the more recent abandonment of harbour roost sites in favour of constructed riverside habitat at Crocodylus Park, close to the foraging sites. |
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| Download | 8. Evidence of rock kangaroo seed dispersal via faecal seed storage in a tropical monsoon community |
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| Authors | Martine, Christopher T.; Boni, Alexandra J.; Capaldi, Elizabeth A.; Lionheart, Gemma E. and Jordon-Thaden,Ingrid E. |
| Abstract | While some of the plant species of the ‘Sandstone Country’ along the escarpment of western Arnhem Land produce fleshy fruits and appear to rely on biotic methods of seed dispersal, little is known about the methods by which this is achieved – and few potential dispersers co-occur in the sandstone outcrop communities. For the present study, scat collections were made on outcrops in the northeastern area of Kakadu National Park with the hope of uncovering relationships between local frugivores and fruit-producers, and providing evidence for seasonal storage of mammal-dispersed seeds in scat prior to germination. The goals of the present project were to collect and identify sandstone community macropod scat, determine the identity of seeds present in the scat, and provide support for the role of browser/grazer macropods as effective seed dispersers via faecal seed storage in an otherwise disperser-poor local fauna. Scat containing seeds was identified as belonging to the Black Wallaroo (Macropus bernardus), a rare and locally-endemic macropod considered an intermediate browser/ grazer. These seeds were successfully germinated and the seedlings identified using molecular phylogenetic techniques as Gardenia fucata (Rubiaceae), an endemic rock-specialist species – thus establishing the first confirmation of effective seed dispersal by a ‘rock kangaroo’ in this region and the first identification of a seed disperser for this uncommon Gardenia species. The results provide support for the role of browser/grazer macropods as occasional effective seed dispersers of rock-specialist plant species in the northern monsoon tropics of Australia via faecal seed storage. |
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| Download | 9. Report of the presence of Hapalotrema synorchis and H. postorchis (Digenea: Spirorchiidae) in marine turtles (Reptilia: Cheloniidae) in Northern Territory waters |
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| Authors | Barton, Diane P.; Chapman, Phoebe A. and Groom, Rachel A. |
| Abstract | The spirorchiid digenean Hapalotrema synorchis was recovered from the heart of a juvenile Hawksbill Turtle (Eretmochelys imbricata) found deceased on a local Darwin beach. The turtle was in poor condition, showing many characteristics associated with spirorchiid infection. A second necropsied turtle showed signs of infection with spirorchiids but adult specimens were not recovered. Examination of specimens held at the Berrimah Veterinary Laboratory found another E. imbricata infected with H. synorchis and a Green Turtle (Chelonia mydas) infected with the related H. postorchis. Despite previous reports of infected turtles, this is the first confirmed identification of H. synorchis and H. postorchis from Northern Territory waters. |
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| Download | 10. Coral communities in extreme environmental conditions in the Northern Territory, Australia |
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| Authors | Ferns, Lawrance W. |
| Abstract | An extensive intertidal reef flat in the macro-tidal marine waters of the Northern Territory was chosen to investigate species composition and zonation persisting under extreme environmental conditions. Thirty-six visual belt transects were used to quantify scleractininan corals, benthic algae and other sessile invertebrates which varied in vertical and horizontal space. Thirty-four coral species were identified. Most species were represented by the family Merulinidae, with lifeform characteristics typical of species specialised in environmental tolerance to high sedimentation, turbidity and temperature (i.e. massive, sub-massive and encrusting growth forms with convex and steep sided morphologies, thick skeletal tissue and large polyps). Whilst the combination of environmental and ecological characteristics of this reef flat community can be viewed as distinctive to the Darwin region, a number of similarities can be compared to reef communities reported in extreme environments of the Arabian Gulf, Red Sea and other regions of tropical northern Australia. |
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| Download | 11. First record of two mangrove leaf slugs, Elysia leucolegnote and E. bangtawaensis (Sacoglossa: Plakobranchidae), in mangrove forests in the Northern Territory |
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| Authors | Bourke,Adam J.; Walker, Carmen and Willan, Richard C. |
| Abstract | Here we report for the first time on the occurrence of the distinctive and highly ephemeral sap-sucking sea slugs Elysia leucolegnote and E. bangtawaensis from mangrove forests from Darwin Harbour, Northern Territory, Australia. Individuals of both species apparently attain smaller body size than their counterparts elsewhere in Australia and the Indo-Pacific region, with maximum extended crawling lengths recorded between 17–22 mm. It appears the northern Australian (i.e. Northern Territory and northern Queensland) populations of E. bangtawaensis differ consistently from their counterparts elsewhere in the world in aspects of (parapodial and rhinophoral) colouration. |
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| Download | 12. Field identification of the Platevindex mangrove slugs (Mollusca: Gastropoda: Onchidiidae) of Darwin Harbour |
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| Authors | Bourke, Adam J. |
| Abstract | Darwin Harbour supports nine species of mangrove slugs (family Onchidiidae) and currently the names of all them are unknown. It appears that the characters distinguishing the two Platevindex species allow animals to be accurately identified in the field on the basis of external characters and on differences in habitat. This note provides descriptions and information on the external characteristics of the two Platevindex species. |
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| Download | 13. Captain King’s lost weevil – alive and well in the Northern Territory? |
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| Authors | Oberprieler, Stefanie K.; Jennings, Debbie and Oberprieler, Rolf G. |
| Abstract | The discovery of a ‘hairy’ yellow weevil in Kakadu National Park in 1995, akin to a widely distributed pest species of agricultural crops in South-East Asia (but not Australia), the so-called ‘Gold-dust Weevil’ (Hypomeces ‘squamosus’), prompted us to investigate the taxonomy and distribution of this weevil in order to determine the identity and origin of the Kakadu specimen. The ‘Gold-dust Weevil’, whose correct scientific name is H. pulviger (Herbst, 1795), is a sexually dimorphic and variable species and has been described under various names in the literature, but its taxonomy and nomenclature have never been investigated. The results of our research to date indicate that it comprises a complex of closely similar species and that the Australian specimen is not conspecific with those occurring further west and north in South-East Asia. We also found that a female conspecific with the Kakadu specimen was likely collected by Captain Phillip Parker King during his surveys of the northern Australian coast in about 1820 and described in 1826 by W. S. Macleay as Cenchroma obscura. King’s weevil has been forgotten for over 200 years, but the discovery of the Kakadu specimen suggests that this species, correctly named Hypomeces obscurus, may be present in northern Australia, albeit scarce and seemingly of no current agricultural concern. |
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| Download | 14. Rediscovery of the Spinifex Sand-skipper (Proeidosa polysema) in the Darwin area, Northern Territory |
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| Authors | Braby, Michael F.; and Westaway, John O. |
| Abstract | The Spinifex Sand-skipper (Proeidosa polysema) (Lepidoptera: Hesperiidae) is recorded from two sites near Noonamah-Berry Springs, approximately 28 km south-east of Darwin. The species is recorded breeding on the grass Triodia bitextura (Poaceae) growing in eucalypt open-woodland in sandy soil derived from laterite. The butterfly had not been recorded from the Darwin area for more than a century (since 1909) and its presence in the rural area confirms earlier historical collections made by renowned entomologist F.P. Dodd. |
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| Download | 15. Book Review |
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| Authors | Dengate, John |
| Abstract | When I was asked to review Dr Grahame Webb’s (2015) book Wildlife Conservation: In the Belly of the Beast, I was a bit uneasy. Cecil, the tame old lion at Hwange National Park in Matabeleland North, Zimbabwe, had just met an untimely end and I had heard Dr Webb’s name associated with trophy hunting. But having come to grips with the book, I must say it’s a valuable contribution to conservation and the issues that surround it. |
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