Cunninghamia : A Journal of Plant Ecology for Eastern Australia, Volume 9, Issue 2 (2005)
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Nectar secretion was measured at 6-h intervals over a 24-h period in flowers of the Red Bloodwood, Corymbia gummifera (family Myrtaceae). Secretion varied among time periods and among trees. There was no clear diurnal or nocturnal pattern. Flowers produced 0.5–3 µl of dilute nectar (9% concentration) per hour throughout the diel cycle. Standing crops of nectar averaged 1–12.6 µl per flower and also varied temporally and spatially. Flowers were visited by a wide array of nectarivores: insects, birds, gliding possums and bats. Although it is likely that these visitors vary considerably in their effectiveness as pollinators, it would appear that Corymbia gummifera has a generalised pollination system.
Acacia blakei forests and scrubs of north-eastern NSW are described and compared to similar vegetation found in the south-east of the state, primarily dominated by Acacia silvestris. Like those in the south, Northern Wattle Dry Sclerophyll Forests form often discrete stands with abrupt margins on steep slopes in rugged terrain on shallow often rocky soils. The structure is usually of a cohort with stems of an even height and size up to 20 m tall, and a sparse understorey with few grasses, herbs or shrubs. These systems are potentially maintained by infrequent extreme fire events. Notes are made on their management and conservation.
New populations of three threatened mallee species, Eucalyptus castrensis K.D.Hill, Eucalyptus fracta K.D.Hill and Eucalyptus pumila Cambage (all Myrtaceae), have recently been found in the Singleton Military Area in the Hunter Valley of New South Wales (32°45’S, 151°15’E). Each population is significant as they increase the known distribution and total numbers of three highly restricted species. Details of the habitat and size of each additional population are given and conservation notes provided.
Cadellia pentastylis F.Muell., (family Surianaceae), a dry rainforest tree with a conservation listing of Vulnerable at state and national levels, was first collected from the Gunnedah area by the botanical collector J.L. Boorman in 1907. We report the first record of Cadellia pentastylis from the Gunnedah area (30°58’49’’S, 150°15’15’’E) since 1907, and provide details of the community and habitat where it occurs, on the lower slopes of Black Jack Mountain. Although this population is one of the smallest in New South Wales, it is significant as it is at its southern distributional limit, and is found adjacent to semi-evergreen vine thicket, another type of dry rainforest, on the same hillslope. We list the New South Wales occurrences of this species and discuss aspects of its flowering phenology.
Fossil spores preserved on historical archaeological sites at Parramatta and Richmond indicate that two or more species of the quillwort genus Isoetes (family Isoetaceae) were growing along rivers on the Cumberland Plain, west of Sydney, during the late 18th and early 19th centuries. Perispore ornamentation indicates the parent plants were related to Isoetes drummondii A.Braun and Isoetes muelleri A.Braun: A possible third species produced microspores that are similar to, but much larger than, the spores produced by modern Isoetes muelleri. Apart from one dubious record, Isoetes has not been found in the Sydney flora or on the New South Wales Central Coast and Central Tablelands botanical subdivisions, but does occur in the Central Western Slopes, and botanical subdivisions to the north of Sydney (North Coast, Northern Tablelands) and south (Southern Tablelands, South-Western Slopes, South-Western Plains), as well as in other States. Our data indicate the present day disjunct distribution of Isoetes in New South Wales is most likely to be due to European settlement. The ability of quillworts to survive moderate levels of disturbance during the early Colonial period raises the possibility that remnant populations may still survive in protected areas on the Cumberland Plain.
The exotic tree species Pinus radiata D. Don (in the family Pinaceae) has successfully spread from commercial plantations into adjacent vegetation in southeastern Australia. Identifying factors facilitating spread will aid the control of current invasions and the prediction of future invasion events. The structure and composition of vegetation can have an important role in determining community resilience to invasion. Two dry eucalypt sclerophyll woodlands in the Blue Mountains west of Sydney known to be invaded by Pinus radiata were surveyed to investigate the influence of eucalypt presence, species diversity, species composition and vegetation cover on the extent and density of invasion. Relationships between community characteristics and the level of pine invasion were weak and variable. Pines were found growing in plots with 0–70% understorey cover and 5–90% ground cover, and in areas of both high and low eucalypt diversity and presence, illustrating the high invasion potential of Pinus radiata.
The vegetation of Culgoa National Park (22 986 ha in area; 29°15’ S, 147°15’ E) in the central north of New South Wales, approximately 40 km west of Goodooga and adjoining the NSW/Queensland border, is described. Six vegetation communities are delineated based on UPGMA analysis of cover-abundance scores of all vascular plant taxa. These communities are mapped based on ground truthing and air photo interpretation. All communities are simple in structure being primarily woodlands, shrublands and grasslands. Communities described are: 1) Eucalyptus coolabah Woodlands, 2) Muehlenbeckia florulenta Shrubby Thickets, 3) Eucalyptus coolabah – Acacia pendula Woodlands & Grasslands, 4) Eucalyptus largiflorens – Eucalyptus coolabah Woodlands, 5) Eucalyptus largiflorens – Alectryon oleifolius Woodlands, 6) Callitris glaucophylla – Eucalyptus populnea Woodlands and Shrublands. A total of 240 vascular plant taxa were found of which 8% were exotic in origin. Conservation issues are discussed.
The vegetation of Warra National Park (29° 29’S, 151° 56’E; 2041 ha in area) and Wattleridge (29°31’S, 151°54’E; 648 ha in area), located approximately 35 km southeast of Glen Innes and 5 km west of Mount Mitchell, within the Guyra and Severn Shires in the New England Tablelands Bioregion NSW, is described. Nine vegetation communities are defined, based on flexible UPGMA analysis of cover-abundance scores of all vascular plant taxa. These communities have been mapped based on analysis of quadrat data, air photo interpretation, substrate variation and ground-truthing.
Communities described are: (1) Leptospermum novae-angliae (New England Tea-tree) – Bursaria spinosa (Blackthorn) Riparian Scrub & Heath, (2) Eucalyptus pauciflora (Snow Gum) – Eucalyptus nova-anglica (New England Peppermint) Woodland, (3) Haloragis heterophylla (Variable Raspwort) – Carex inversa (Sedge) Herbfield, (4) Baeckea omissa (Baeckea) – Leptospermum gregarium (Swamp Tea-tree) Closed Wet Heath, (5) Eucalyptus cameronii (Die-hard Stringybark) – Eucalyptus campanulata (New England Blackbutt) Shrubby Open Forest, (6) Eucalyptus radiata subsp. sejuncta (Narrow-leaved Peppermint) – Eucalyptus acaciiformis (Wattle-leaved Peppermint) Woodland, (7) Eucalyptus cameronii (Die-hard Stringybark) – Eucalyptus caliginosa (Broad-leaved Stringybark) Grassy Open Forest, (8) Eucalyptus nobilis (Manna Gum) – Eucalyptus obliqua (Messmate) Tall Open Forest, and (9) Eucalyptus obliqua (Messmate) – Eucalyptus nobilis (Manna Gum) Tall Open Forest, (10) Leptospermum novae-angliae – Kunzea obovata – Brachyloma saxicola Shrubby Open Scrub and Closed Heath.
Of 11 communities within the area, four should be considered as threatened, while 18 taxa are considered to be of conservation significance.
The Southern Forests study area covers an area of about six million hectares of south-eastern New South Wales, south of Oberon and Kiama and east of Albury and Boorowa (latitude 33° 02’–37 ° 06’ S; longitude 146° 56’ – 147° 06’ E). The total area of existing vegetation mapped was three million hectares (3 120 400 hectares) or about 50% of the study area. Terrestrial, wetland and estuarine vegetation of the Southern Forests region were classified into 206 vegetation groups and mapped at a scale between 1: 25 000 and 1: 100 000. The classification was based on a cluster analysis of detailed field surveys of vascular plants, as well as field knowledge in the absence of field survey data. The primary classification was based on 3740 vegetation samples with full floristics cover abundance data. Additional classifications of full floristics presence-absence and tree canopy data were carried out to guide mapping in areas with few full floristic samples. The mapping of extant vegetation was carried out by tagging vegetation polygons with vegetation codes, guided by expert knowledge, using field survey data classified into vegetation groups, remote sensing, and other environmental spatial data. The mapping of pre-1750 vegetation involved tagging of soils mapping with vegetation codes at 1: 100 000 scale, guided by spatial modelling of vegetation groups using generalised additive statistical models (GAMS), and expert knowledge. Profiles of each of the vegetation groups on the CD-ROM* provide key indicator species, descriptions, statistics and lists of informative plant species.
The 206 vegetation groups cover the full range of natural vegetation, including rainforests, moist eucalypt forests, dry shrub forests, grassy forests, mallee low forests, heathlands, shrublands, grasslands and wetlands. There are 138 groups of Eucalyptus forests or woodlands, 12 rainforest groups, and 46 non-forest groups. Of the 206 groups, 193 were classified and mapped in the study area. Thirteen vegetation groups were not mapped because of their small size and lack of samples, or because they fell outside the study area.
Updated regional extant and pre-1750 vegetation maps of southern New South Wales have been produced in 2005, based on those originally prepared in 2000 for the southern Regional Forest Agreement (RFA). Further validation and remapping of extant vegetation over 10% of the study area has subsequently improved the quality of the vegetation map, and removed some of the errors in the original version. The revised map provides a reasonable representation of native vegetation at a scale between 1: 25 000 and 1: 100 000 across the study area.
In 2005 native vegetation covers 50% of the study area. Environmental pressures on the remaining vegetation include clearing, habitat degradation from weeds and nutrification, severe droughts, changing fire regimes, and urbanisation. Grassy woodlands and forests, temperate grasslands, and coastal and riparian vegetation have been the most reduced in areal extent. Over 90% of the grassy woodlands and temperate grasslands have been lost. Conservation of the remaining vegetation in these formations is problematic because of the small, discontinuous, and degraded nature of the remaining patches of vegetation.