Cunninghamia : A Journal of Plant Ecology for Eastern Australia, Volume 11, Issue 1 (2009)
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In early January 1994 wildfires burned areas of bushland in northern Sydney (lat 33° 45’ S, long 151° 05’ E) in coastal south-eastern Australia. This paper reports observations of the fire responses for 828 species of bushland plants – 576 native species and 252 exotic species in the Lane Cove River and Narrabeen Lagoon catchment areas. Information recorded includes whether a species was killed by fire or resprouted post-fire, when seedlings were first observed following fire, and the times of first flowering and first fruiting (or spore production) after the fires. The estimated peaks of post-fire flowering or fruiting for a few species are given. It was not practicable to record data in all categories for all of the 828 species due to the logistical challenges involved in recording data across a large area of bushland, over a number of years. The data presented add to the growing body of knowledge on plant fire responses and will assist the management and conservation of bushland in the study areas, as well as the broader Sydney region.
Tasmania has a strong record of successful in situ plant conservation but there will always be a role for the integration of various ex situ measures into a plant conservation program due to pressure by threatening processes on wild populations. This paper replaces a 15 year old strategy for ex situ conservation in Tasmania. Progress in ex situ measures for Tasmanian plants is described and broadly evaluated against the previous strategy. Rare and threatened species are considered to be a high priority group for resources if intensive management is required. Endemic species likely to be adversely impacted by climate change would be a high priority for ex situ conservation. Seed banking to capture as much genetic variation in these species is suggested. Eight ex situ methods are briefly described and their application in Tasmanian instances noted. The Tasmanian Seed Conservation Centre established at the Royal Tasmanian Botanical Gardens is a central part of Tasmanian ex situ conservation efforts for ex situ conservation programs. An ongoing role for this facility is considered fundamental.
A checklist of vascular plants of the 15 Capricorn-Bunker Islands (CBI) (lat 23° 11’ to 24° 07’S; long 151° 43’ to 152° 43’E) compiled from 2007/08 surveys, recorded 131 vascular plant species including 44 (34%) native and 87 (66%) naturalized species from 55 families and 104 genera. New native records include Hernandia nymphaeifolia and Boerhavia sp. (Bargara L.Pedley 5382). An increase of about 35 exotic species over 23 years was recorded indicating a weed incursion rate of 1.5 species per annum. Cakile edentula (13 islands) and Solanum americanum (12 islands) are the most widespread exotic weeds. The naturalised flora ranged from 5% at Erskine Island (low disturbance) to 68% at Lady Elliot Island (very high disturbance). Achyranthes aspera, Argusia argentea and Pisonia grandis are the only species found on all 15 islands. Six indigenous species are limited to one island: Boerhavia sp. (Bargara L.Pedley 5382), Calophyllum inophyllum, Clerodendrum inerme, Hernandia nymphaeifolia, Stephania japonica and Ximenia americana. Patterns of plant distributions, diversity and origin are discussed. Eleven indigenous species reach their southern limit at the CBI, indicating connectivity with the Indo-Pacific region. PATN analyses using native flora generated two island groups. Tryon, Heron, North West, Masthead, Wilson, Wreck and Erskine Islands are the most closely related islands. Another group of related islands includes North Reef, Lady Musgrave, Fairfax Islands, Hoskyn and One Tree Islands. With the inclusion of the exotic flora, Lady Elliot Island separated into its own distinct group. Greater conservation management efforts are required to control and minimise the introduction of exotic weed species to islands with high human visitation.
A checklist of vascular plants of Coringa-Herald National Nature Reserve (CHNNR) (17º 11’S, 149º 00’ E to 16º 23’S, 150º 30’E and Willis Island (16º 24’S, 149º 58’E) at the northern Coral Sea Islands Territory of Australia compiled during 2006/07 surveys, recorded 30 species including 18 species indigenous to the Coral Sea Islands (60%), 10 exotic species (33%) and two that were planted (7%). Plant life-forms included: 5 species of trees and tall shrubs (17%), 2 species of low shrubs (6.5%), 21 herbs (70%), and 2 vine/creepers (6.5%). Plant dispersal for the 30 species is predominantly by human activities (40%), ocean currents (33%) and seabirds (27%). The garden species and dispersal modes at Willis Island indicate that non-residential casual human visitation at CHNNR has at present had little effect on establishment of exotic weeds. Resilience of leverage flora, floristic diversity and species origins of CHNNR are discussed in relation to its connectivity with the Melanesian region due to the South Equatorial Current operating in the region. Colubrina asiatica was recorded as a new record for oceanic islands in Australian territories. Previously recorded Ximenia americana and Digitaria ctenantha are considered locally extinct. Pattern analyses indicate that cays of similar size and vegetation structure are the most similar in floristic composition. Willis Island flora is relatively dissimilar to the CHNNR cays, due to the influence of anthropogenic activities associated with a staffed weather station.
Vascular plants present in groundstoreys of variously–managed areas in four cemeteries in central western NSW – two on the Central Western Slopes (Garra and Toogong) and two on the Central Tablelands (Lyndhurst and Carcoar) – were recorded over periods of 6–10 years. It was hypothesised that (a) areas of the cemeteries with a history of nil or low disturbance would represent high quality remnant vegetation (i.e. contain a diversity of native species but few naturalised species), and (b) that clearing of woody vegetation, together with similar management (e.g. regular mowing) would result in homogenisation of the groundstoreys such that many species, native and naturalised, would be common to all sites. 344 species (176 native, 154 naturalised and 14 non–naturalised exotics) were recorded across the four cemeteries. Many native species that were rare in the surrounding agricultural lands were present in the cemeteries (enhancing their value as conservation areas) but no cemetery contained areas of groundstorey that would qualify as ‘pristine’. Across all management areas, the proportions of naturalised species in the native + naturalised floras of the cemeteries ranged from 46 to 55 %. Though never dominant, naturalised species also comprised high proportions (42 to 51 %) of the floras of the least disturbed (nil or infrequently mown) areas within each cemetery. Many (40 %) of the species recorded occurred at only one cemetery. This partly explained why the floras of similarly– managed parts of cemeteries on the Central Western Slopes were, contrary to expectations, markedly different to those on the Central Tablelands. However, within the same botanic subdivision, floras – particularly of naturalised species in regularly mown grasslands – were more similar (‘homogenised’) than those of nil or infrequently mown grasslands.
Twenty-eight natural populations of Wallaby Grasses, Austrodanthonia species, in central western New South Wales were sampled and species presence related to a suite of environmental characteristics. An average of 12 plants were selectively sampled from each population; most populations consisted of at least four out of five species, Austrodanthonia bipartita, A. caespitosa, A. eriantha, A. fulva and A. setacea. Numerous ecological factors allowed the widespread co-occurrence of these closely-related species. Large-scale rainfall and climatic factors were correlated with species-presence but no universal small-scale site environmental variables were important for all species. The most widespread species was Austrodanthonia caespitosa and environmental variations at a local site scale, depending on exposure to solar radiation, may at least partially overcome regional rainfall and climate influences.
The floristic composition and extent of Carex-dominated fens in the New South Wales New England Tablelands Bioregion and Barrington Tops area (lat 28° 41’ S–31° 55’ S; long 151° 23’ E–152° 05’ E) together with outliers from the central west (Coonabarabran) are described from 81 full floristic survey sites. These fens contained 234 vascular plant taxa of which 27% were exotic. The fens were dominated by herbaceous vegetation (96% of taxa). Cluster analysis of cover-abundance scores of vascular plant taxa from 81 plots placed within 71 separate Carex fens revealed three alliances: 1) Carex appressa, 2) Scirpus polystachyus – Carex tereticaulis and 3) Carex gaudichaudiana and seven communities: (1) Carex appressa – Stellaria angustifolia Fen (2) Carex appressa Fen (3) Scirpus polystachyus – Carex appressa Fen (4) Carex tereticaulis Fen (5) Carex gaudichaudiana – Isachne globosa Fen (6) Carex sp. Bendemeer – Carex gaudichaudiana Fen (7) Carex gaudichaudiana – Glyceria australis Fen The distribution of alliances showed a pattern of east-west separation. The most easterly alliance shares many features with the Carex gaudichaudiana Alliance of the Monaro Region of southern NSW while the other alliances have no counterparts within the current literature. We estimate that up to 5 000 ha of fen vegetation survive in the New England Bioregion of which 90% is on grazed land and only 0.2% is within conservation reserves. Seven outstanding examples of fens remain; most are examples of Community 5, with one representing Community 6 and none representing the other five communities. Many of these are not secured, and none of those within reserves are in their ‘natural’ state. We therefore strongly encourage measures to allow closure of drains, the opening of dams, and the rehabilitation of important fens such as Bishops, Racecourse and New Country Swamps.
We use historical information and extensive contemporary surveys to describe the pre-European vegetation of the Nepean Peninsula, an extensive area of calcareous sand dunes at the tip of the Mornington Peninsula, south of Melbourne, Victoria (38º19’S 144º43’E). We conclude that much of the area was once covered by open, grassy woodlands, variously dominated by Allocasuarina verticillata (Drooping Sheoak), Banksia integrifolia subsp. integrifolia (Coast Banksia), Acacia species (Wattles), and Melaleuca lanceolata subsp. lanceolata (Moonah), along with a range of other species. Some areas supported shrublands, woodlands, forests, grasslands and wetlands. This area was markedly distinct from most other nearby areas, and has ecological affinities with areas in western Victoria. Over 200 years of ‘European’ land use have left this landscape remarkably different today – even in places where native vegetation persists. We review and discuss the environmental factors that have influenced the pattern and structure of the vegetation.
The Entrance Point Scientific Reference Area (lat 38º 48’ S long 146º 38’ E) in the north-eastern corner of Wilsons Promontory, Victoria, is notable for numerous parallel sandy dune ridges covered with dense Leptospermum laevigatum scrub. As a result of some demanding field work in a relatively remote area, together with aerial photos, I have been able to observe the development of this dune topography and follow the vegetation succession from 1981 to 2000. After a period of erosion early in the 20th century, shore progradation and ridge formation resumed in the central section of the beach between Entrance and Hunter Points and later extended southward. The parallel ridges were found to be the result of successive berm and pool formation on the upper beach of the prograding shoreline. Berm overwash during spring and storm tides fills the depression behind the berm and after the tide has gone out leaves behind a long narrow pool. Buoyant Atriplex cinerea fruits present in the flotsam strand on either or both of the pool margins, depending on prevailing wind directions. After fruits have germinated, seedlings provide nuclei for sand accumulation. If they are sufficiently numerous, a dune ridge builds up along the outer pool margin while plants on the inner margin contribute to the consolidation of the previous ridge. As long as progradation continues, this process is repeated at intervals and results in the formation of series of parallel dune ridges. A small number of other species establish in the lee of the new ridge. Acacia sophorae with its fast growth and spreading habit, together with Olearia glutinosa contribute to stabilising the ridge. They provide protection for Leptospermum laevigatum, Myoporum insulare and Banksia integrifolia during their early growth. After about 20 years, Leptospermum laevigatum becomes the dominant element of the scrub as Acacia sophorae diminishes in vigour and eventually dies. Virtually no evidence, even on the oldest ridges, was found of candidate species to continue the succession and hence, Leptospermum laevigatum thicket needs to be regarded as the end of the succession on young dune ridges. Once the pool depressions are cut off from flooding by seawater, the groundwater freshens and a sward of Isolepis cernua and Samolus repens, often with Juncus kraussii and Isolepis nodosa on somewhat higher areas, becomes established. Flooding occurs during heavy rain and water may stay above the surface for several days. At the same time, the older ridges of the central section were attacked by erosion which left large amounts of tree debris on the upper beach. This erosion resulted in the formation of a spit which, in time, carried a series of successively younger ridges built on flotsam lines. Atriplex cinerea was again the dominant pioneer species, but in the 1990s the influence of *Thinopyrum junceiforme had become equally important. Succession on these ridges was similar to that of the ridges on the prograding beach, but scrub height remained somewhat lower. Saltmarsh vegetation, dominated by Sarcocornia quinqueflora, gradually established in the lower sections between the ridges. However, the impact of erosion which had provided the sediment for building the spit, gradually shifted northward and began to destroy what had come into existence only decades earlier. Beach progradation along the western entrance to Corner Inlet is fortuitous and linked to changing channel locations in the tidal delta, while the dominant role of Atriplex cinerea in incipient dune formation is a consequence of the relatively sheltered environment at the entrance. It could well be that this combination of environmental factors is rarely if ever duplicated elsewhere in Australia.