Cunninghamia : A Journal of Plant Ecology for Eastern Australia, Volume 12, Issue 2 (2011)
Refine
Document Type
- Article (6)
Language
- English (6)
Has Fulltext
- yes (6)
Is part of the Bibliography
- no (6)
A resurvey (previously surveyed 2003–04) of the northern metapopulation of the listed Vulnerable shrub Astrotricha crassifolia (family Araliaceae) near Gosford, New South Wales, revealed six additional small subpopulations nearby, bringing to nine the total number, all in Brisbane Water National Park. While the stem count of the previously measured sites remained largely the same, the discovery of further subpopulations has increased the total known stem number to 1211 stems, with an area of occupancy of only 385 m2. The majority (nearly 80%) of these subpopulations are very small, directly adjacent to roads, and remain vulnerable to park management and maintenance practices. Astrotricha crassifolia is surviving due to its successful rhizomatous growth, but may not be reproducing from seed. This paper recommends some changes to management to reduce potential threats.
European settlement in Australia has always been concentrated along or close to the coast. As a consequence, saltmarshes, mangroves and other coastal marshes have experienced a long history of modification and destruction. Depletion statistics are available for many coastal marshes in the Northern Hemisphere and, in Australia, for parts of New South Wales and Queensland. There are no equivalent State-wide data for Victoria. Using a suite of historical information, including extensive use of early surveyors’ maps, we aimed to provide a consistent view of the change in the extent of coastal marshes since European colonization in Victoria (i.e. the mid-19th century). Notwithstanding the difficulties of interpretation, we estimate that prior to European colonization Victoria supported approximately 346– 421 km2 of coastal marsh, of which approximately 80–95% remains. Although a simplistic interpretation suggests a net loss of 5–20% in wetland area over this time period, it is clear that some parts of the coast have experienced relatively little change since the mid 19th century whereas others have been severely depleted and, in a few sectors, there may have been an expansion of coastal marsh. The situation with the Gippsland Lakes is complex, and according to the method used to interpret the original data sources there has either been a substantial increase or a loss of up to 35% in wetland area around Lake Wellington. The largest absolute losses have probably been of EVC 140 Mangrove Shrubland and of coastal saltmarsh dominated by Tecticornia spp. Parts of the coast where significant losses have occurred include the Lonsdale Lakes, western shore of Port Phillip Bay, Anderson Inlet, Shallow Inlet, Powlett- Kilcunda, Corner Inlet and Nooramunga, and possibly Lake Wellington. With the exception of the Lonsdale Lakes, all these areas are situated along the Gippsland coast. Changes to coastal marshes have not stopped and are unlikely to cease in the near future. The destruction of coastal marshes for industrial development remains an ongoing threat in many regions (e.g. in Western Port) and is likely to be compounded by climate change and, in particular, sea-level rise.
Does an increase in the cover/abundance of Callitris glaucophylla or Callitris endlicheri affect the number of species recorded in plots (species density) or do other factors such as altitude or logging, fire or grazing history have greater explanatory power? This was tested using survey data from 1351 plots from northern New South Wales. Altitude was found to have the greatest explanatory power in predicting the number of species per plot. Increasing cover/abundance of Callitris glaucophylla was found to be positively correlated with increasing species density. Fire was found to have a minor negative effect on species density in Callitris glaucophylla stands and grazing a small positive correlation in Callitris endlicheri stands.
Although the distribution and composition of cool temperate rainforest in eastern Australia may be regarded as well documented, the recent discovery of cool temperate rainforest stands dominated by Atherosperma moschatum in the Pilot Wilderness area of Kosciuszko National Park shows that our knowledge is still incomplete. The additional discovery of 10 plant species previously unrecorded for the park including large specimens of Elaeocarpus holopetalus highlights the fact that although the flora and vegetation of the alpine and subalpine tracts of Kosciuszko National Park are relatively well studied, the remainder of the park is by comparison understudied and under sampled. Although not actively protected or managed, these cool temperate rainforest stands appear to have been little affected by the 2003 fires in the Australian Alps, with only 2 stands out of 25 showing any fire incursion. However, whether the direct effects of climate change or the indirect effects of human reaction to climate change poses the greatest threat to the continued existence of these stands is an open question. The aim of this short communication is to: a) examine the distribution and composition of these newly discovered stands of cool temperate rainforest and b) to briefly describe the impact of the 2003 fires on this restricted vegetation type.
Multivariate analysis and non-metric multidimensional scaling have been used to compare the floristic composition of vegetation dominated by Spotted Gum, Corymbia maculata, and Grey Ironbark, Eucalyptus paniculata, from the Pittwater and Gosford local government areas, and elsewhere on the Central Coast of New South Wales. When placed within a regional context, vegetation from both local government areas is strongly related, and is sufficiently distinct (at 30% similarity) from other areas of Spotted Gum-Ironbark vegetation within the region to warrant their collective consideration as Pittwater Spotted Gum Forest (PSGF), an Endangered Ecological Community in New South Wales. Within Pittwater local government area, two forms of PSGF are present: a dryer, more widespread form present on ridges and slopes, and a moister form with strong littoral rainforest affinities confined to gullies. Gosford local government area supports only the dryer form. Extant and pre-1750 mapping of PSGF from both local government areas (excluding Ku-ring-gai Chase National Park) shows a total extant distribution of 227 ha, and since 1750 an estimated loss of 727 ha (76%) from the original 954 ha. PSGF is present in two secure conservation reserves: Ku-ring-gai Chase National Park (~40 ha, Thomas & Benson 1985) and Bouddi National Park (~30 ha, Bell 2009), totaling ~ 70 ha. Despite this, much of the extant distribution lies at the reserve-urban interface, and is subject to ongoing threats of regular low-intensity fire, unmitigated clearing and weed invasion.
The grass Elymus multiflorus subsp. kingianus (family Poaceae) is considered to be endemic to Lord Howe and Norfolk Islands. We assessed the conservation status of the taxon on Lord Howe Island, New South Wales, and undertook targeted field surveys across three years and several seasons in suitable habitat, based on the single previously recorded location. We found the species occurrence on Lord Howe Island was highly restricted, with only a few plants found at 2 locations in close proximity. A number of exotic grasses pose a threat to the long-term conservation of the taxon, which was assessed as being eligible for listing as critically endangered under the NSW Threatened Species Conservation Act 1995.