457 research outputs found

    Montane lakes (lagoons) of the New England Tablelands Bioregion

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    The vegetation of montane lagoons of the New England Tablelands Bioregion, New South Wales is examined using flexible UPGMA analysis of frequency scores on all vascular plant taxa, charophytes and one liverworts. Seven communities are described: 1. Hydrocotyle tripartita – Isotoma fluviatilis – Ranunculus inundatus – Lilaeopsis polyantha herbfield; 2. Eleocharis sphacelata – Potamogeton tricarinatus sedgeland; 3. Eleocharis sphacelata – Utricularia australis – Isolepis fluitans, herbfield; 4. Utricularia australis – Nitella sonderi herbfield; 5. Eleocharis sphacelata – Utricularia australis – Ricciocarpus natans sedgeland; 6. Carex gaudichaudiana – Holcus lanatus – Stellaria angustifolia sedgeland; 7. Cyperus sphaeroides – Eleocharis gracilis – Schoenus apogon – Carex gaudichaudiana sedgeland. 58 lagoons were located and identified, only 28% of which are considered to be intact and in good condition. Two threatened species (Aldovandra vesiculosa and Arthaxon hispidus) and three RoTAP-listed taxa were encountered during the survey

    Wallum on the Nabiac Pleistocene barriers, lower North Coast of New South Wales

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    Wallum is widespread on coastal dunefields, beach ridge plains and associated sandy flats in northern NSW and southern Queensland. These sand masses contain large aquifers, and the wallum ecosystem is considered to be generally groundwater-dependent. This study describes the floristic composition and environmental relations of wallum on a Pleistocene barrier system at Nabiac (32˚ 09’S 152˚ 26’E), on the lower North Coast of NSW. Despite their minimal elevation and degraded relief, the Nabiac barriers maintain floristic patterns related to topography and hence groundwater relations. Comparative analyses identified the Nabiac wallum as representative of the ecosystem throughout large parts of its range in eastern Australia. The Nabiac wallum and nearby estuarine and alluvial vegetation supports species and communities of conservation significance. A borefield is proposed for development on the Nabiac barriers, thereby providing a valuable opportunity for research into mechanisms of groundwater utilisation by the wallum ecosystem

    Pre-clearing vegetation of the coastal lowlands of the Wet Tropics Bioregion, North Queensland

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    A pre-clearing vegetation map and digital coverage at approximately 1:50 000 scale for the coastal lowlands (up to about 200 m elevation) of the Wet Tropics Bioregion, North Queensland is presented. The study area covers about 508 000 ha from Cooktown, 420 km south almost to Townsville (latitude 15° 30’–18° 20’ longitude 144° 50’–146° 40’). Data sources included historical aerial photography, early surveyors’ plans, explorers’ journals, previous vegetation maps, and maps of soils and geology. The pre-clearing mapping was built around the remnant vegetation mapping of Stanton & Stanton (2005), and the vegetation classification of this latter work was adopted. Vegetation units were further classified into regional ecosystems compatible with the standard State-wide system used by Queensland government. The digital coverage is part of the current Queensland Herbarium regional ecosystem coverage (Queensland Herbarium and Wet Tropics Management Authority 2005). Coloured maps (1:100 000 scale) of the pre-clearing vegetation of the Herbert, Tully, Innisfail and Macalister/Daintree subregions are on an accompanying CD-ROM. An evaluation of vegetation loss through clearing on the coastal lowlands of the Wet Tropics revealed several nearextinct vegetation communities and regional ecosystems, and many others that are drastically reduced in area. Even ecosystems occurring on poorly drained lands have suffered a surprisingly high level of loss due to the effectiveness of drainage operations. Grassland ecosystems were found to be widespread on the Herbert and Tully floodplains, but are now close to extinction. The lowlands vegetation of the Wet Tropics that remains today continues to be fragmented and degraded despite the introduction of State-wide broad-scale tree-clearing laws in 1999, and the cessation of broadscale tree-clearing in December 2006

    Wetland biodiversity in coastal New South Wales: the Wallis Lake catchment as a case study

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    The floristic composition and environmental relations of wetland vegetation in the Wallis Lake catchment (32˚ 09’S; 152˚ 20’E), area 1292 km2, on the lower North Coast of NSW are described. The catchment supports wetlands listed as Endangered Ecological Communities (NSW Threatened Species Conservation Act 1995) and plant species of high conservation value. A methodology of air photo interpretation, site-based sampling (114 quadrats) and landscape differentiation was developed. A total of 393 vascular plant taxa were recorded (including 10% exotics). Wetland vegetation formations and subformations including mangrove forest, swamp sclerophyll forest, wet heathland, chenopod shrubland, tussock grassland, sedgeland and rushland are described using numerical classification. 31 plant species of national or regional conservation significance are identified. Four Endangered Ecological Communities are discussed – Coastal Saltmarsh, Swamp Oak Floodplain Forest, Swamp Sclerophyll Forest on Coastal Floodplains, and Freshwater Wetlands on Coastal Floodplains. A key recommendation is the completion of reliable wetland vegetation and soil landscape mapping for all land tenures in the catchment – to assess wetland condition and conservation significance, and representation in formal conservation reserves, thereby directing future priorities for the protection of wetland biodiversity on both public and private lands. The methodology developed can be applied to the survey and conservation of wetland biodiversity in other parts of coastal NSW

    A classification of New Zealand’s terrestrial ecosystems

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    This study produces a comprehensive terrestrial ecosystem classification by subjectively constructing a heirarchy of perceived key environmental drivers. Introduction: The ecosystem concept is at the centre of international agreements, New Zealand legislation, and modern policy and planning systems that aim to sustainably manage natural resources. All definitions of ecosystems include the concept of the physical environment being integrated with its biotic components. Functionally, the concept embodies disturbance cycles, and flows of energy, nutrients and non-living materials, with these processes underpinning the concept of ecosystem health or integrity. Since these processes operate at variable spatio-temporal scales, and species and communities intergrade variably along environmental gradients, there is no single optimal scale at which to apply the ecosystem concept. Rather, the openness and hierarchical nature of ecosystem processes lead to any one classification scale being viewed as nested within coarser and finer scale components. One of the goals of the New Zealand Biodiversity Strategy is to ‘maintain and restore a full range of remaining habitats and ecosystems …’. However, although many environmental agencies and individuals can contribute to this goal, any investment decisions are currently being made in the absence of a comprehensive list of ecosystems or a systematic threat ranking. Therefore, classification of the full range of ecosystem types for New Zealand is overdue.   &nbsp

    Mammals of the Upper Henty River Region, Western Tasmania

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    A mammal survey was conducted in the Upper Henty River Region in western Tasmania. The area had been subject to much disturbance from mining, forestry and frequent fires and was covered by a maze of roads and tracks. Nineteen native species (including bats) were recorded. Four of the species listed in 1983 as occurring in the Lower Gordon Region, 80 km south of the present study area, were not recorded during our survey. It is considered that three of these species would probably have been found in the area with further searching. The fourth species, Mastacomysfuscus, is thought not to be present due to increased fire frequency in the sedgeland areas compared with the Lower Gordon Region. Potorous tridactylus is recorded for the first time from rainforest. Microhabitat selection by Rattus lutreolus and Pseudomys higginsi differed from that previously reported. Disturbance from road construction led to the creation of a new food source for Thylogale billardierii. The abundance of tracks in the area increased ease of movement for carnivorous mammals. Only one introduced species Felis catus, which is also known to occur in the Lower Gordon, was recorded. Disturbance had thus not led to an invasion of exotics

    The faunal assemblage in freshwater crayfish burrows in sedgeland and forest at Lightning Plains, western Tasmania

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    The faunal assemblage of crayfish burrows was examined intensively at Lightning Plains in wesrern Tasmania, in sedgeland and adjacent forest, to determine variations in species occurrences and abundances both within one habitat type and between two habitats. Species -sample curves showed that over 90% of the species found in ten samples could be collected by taking only five. Despite the fact that the host crayfish species was the same, each habitat was found to display a characteristic assemblage. Variations between the assemblages are attributed to differences in soil conditions, vegetation structure and watertable behaviour

    Small terrestrial mammals and bats of Melaleuca and Claytons, southwestern Tasmania

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    A survey of small terrestrial mammals and bats was undertaken in two areas of southwestern Tasmania: around Melaleuca, in sedgeland, scrub and woodland communities, and at Claytons in mixed forest. The density of bats was extremely low in comparison with populations in eastern Tasmania. The densities of Rattus lutreolusand Antechinus minimuswere greatest in sedgeland/scrub with a dense undergrowth. Pseudomys higginsi was only captured in mixed forest but is also present around Deny King's garden. Dasyurus viverrinus was most abundant in young sedgeland. Cercartetus nanus was present at both Clay tons and Melaleuca. No introduced rodents were trapped, but an outbreak of Rattus rattus had occurred previous to our study. No Mastacomys fuscus were trapped but they have been recorded in a previous study. Fire has an important influence on the composition and structure of the vegetation which, in turn, influences the composition and density of the mammal community

    Key ecological sites of Hamilton City: Volume 1

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    Ecological sites of significance previously identified in 2000 were reviewed in 2011. Natural vegetation in areas acquired by the city since 2000 was also surveyed to identify any new key sites. In total seventy key sites that met the Waikato Regional Council Regional Policy Statement criteria for ecological significance were identified across Hamilton City. Of the original key sites, the total area covered by sites, average site size and overall quality of sites had increased between the 2000 and 2011 surveys. This was due to restoration efforts across the city by Hamilton City Council and the community. Vegetation restoration efforts have had other biodiversity and ecological benefits such as providing additional habitat for the city’s increasing tui population. Key sites are not spread evenly across the city or across landform types. Most key sites are either in gullies or adjoining the Waikato River. Less than 1% of urban alluvial plains and peat bogs are key sites. Two sites on private land have degraded and no longer meet the ecological significance criteria in 2011. The current survey utilised a standard methodology focused on vegetation types. There will be other significant sites not identified including sites with significant fauna values but a detailed and costly survey would be required to identify all such sites. The 1.5% of the city area covered by key sites is well below the 10% minimum recommended to prevent biodiversity decline in urban areas. Areas where vegetation restoration has begun in the city have the potential to expand existing key sites or develop new sites if council and community efforts continue in the future. The Council and its restoration partners should continue to seek ways of increasing native vegetation cover in Hamilton City and restoration of the distinctive gully landform remains the best option

    Microhabitat use by Gilbert\u27s Potoroo (Potorous Tridactylus Gilbertii Gould) in Relation to Vegetation Associations and Ground Cover

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    Gilbert\u27s potoroo has been rediscovered 120 years after it was believed to have become extinct. In 1994 the presence of Gilbert\u27s potoroo was confirmed at Two Peoples Bay Nature Reserve, near Albany, and since that time the need for a detailed understanding of the biology and behaviour of the species has become urgent. An understanding of the habitat requirements of the species will aid in its recovery from its present critically endangered status and will act as a guide for future management decisions concerning translocations of new populations into other areas. The present study was conducted at Two Peoples Bay Nature Reserve in Western Australia in order to determine the microhabitat requirements of the species, with particular reference to vegetation associations and density of canopy cover utilised. The study was conducted on both female and male adult specimens of the nocturnal marsupial species Potomus tridactylus gilbertii Gould. Investigation of microhabitat preferences was undertaken using a modified spool-and-line tracking technique, giving a detailed record of the movement of the animals through the habitat. The habitat within the study area is comprised mainly of dense coastal heath dominated by Melaleuca and Agonis spp. with A/locasuarina spp. emergents. It is fragmented by wet and dry sclerophyll forest along gullies and granite outcrops and large sedgelands dominated by Anarthriaspp. The spool lines were not clearly associated with any particular floristic group or strongly correlated with any particular density of cover. Instead it appeared that animals utilised a range of vegetation ecotones, with dense cover possibly being utilised for diurnal shelter and protection from predators, and more open areas for nocturnal foraging
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