Changes in a forest bird community during a period of fire and drought near Bega,New South Wales

The bird community of a forested 13 ha plot was studied for 3 years, during which the plot was burnt by wildfire and was severely drought-affected. The combined effects of fire and drought were surprisingly limited. Similar numbers of species were recorded in each year and differences in species composition involved only rare visitors to the plot. Colour-banding indicated population declines in at least six resident species. The greatest decline was that of the Brown Thornbill (Acanthiza pusilla), from 20 pairs to 10 pairs. In general, insectivorous birds were most abundant and widespread on the plot during the first year, before the fire. In contrast, nomadic birds feeding on flowers or fruits were most abundant in the second year, when there was a prolific flowering and fruiting of several important food plants. After the fire, at least ten bird species avoided the burnt ridges and became more concentrated in the unburnt gullies. Most were species associated with dense shrub thickets, the layer of vegetation most affected by the fire. It seems that gullies are major refuge areas in these forests and are the key to the resilience of the bird community to fire and drought.     

Effects of climate,natural enemies and biocides on three citrus mites in coastal New South Wales

Infestations of the citrus rust mitePhyllocoptruta oleivora (Ashmead), the brown citrus rust miteTegolophus australis Keifer, and the citrus red mitePanonychus citri (McGregor), did not cause economic damage to orange (Citrus sinensis (L.) Osbeck) in two coastal New South Wales orchards during a three-year study. The seasonal abundance of the mites and their phytoseiid and coccinellid predators was defined using periodic regressions of transformed counts on time. Population peaks coincided with seasonal rises and falls in temperature and evaporation in late-summer/autumn and in spring/early-summer. Population troughs in late-spring/summer coincided with peaks in temperature and evaporation and reproductive dormancy in some of the coccinellids. Population troughs in winter generally coincided with troughs in evaporation and temperature, particularly in July when the average temperature was about 10°C. Partial correlation coefficients were used to determine the relationships between the predators and their prey. These were mostly nonsignificant atP=0.05. Fortnightly and daily fluctuations in weather did not have any obvious effects on numbers of the mites. The effects of fungicides and pesticides applied during the study were not clear.     

Litterfall and decomposition in the Pilliga State Forests,New South Wales,Australia

Abstract The annual litterfall and decomposition rate of litter in three semi-arid vegetation communities (forest, mallee and broom) in the Pilliga State Forests, New South Wales, Australia, were measured over a period of 3 years. Annual litterfall was found to vary widely between the communities, ranging from 1005 to 3409 kg ha^?1 year^?1. Decomposition rates were measured and the half lives obtained ranged from 2. 5 to 5. 3 years. In many forests fire removes much of the accumulated litter at regular intervals. Two of the three study sites (the forest and mallee) had reached steady state after 36 years of litter accumulation after fire, while the broom, with only 20 years accumulation, was not in steady state. Between fires decomposition of the liner dominates. In the mallee soil fauna were most active, burying the litter under mineral soil before comminution commenced, demonstrating a cycling of litter which differs markedly from that in more humid climates.     

Patterns in shallow subtidal marine assemblages along the coast of New South Wales

Shallow subtidal areas of rocky reefs in central and southern New South Wales may best be described as a mosaic of habitats, the distributions of which are seemingly related to depth, wave exposure and a number of biological processes, particularly herbivory. The Fringe habitat is generally found only in the most shallow waters. Forests of the laminarian alga Ecklonia radiata are often found at intermediate depths. In deeper, or more sheltered water, sponges, ascidians and red algae are more abundant and the abundances of sea urchins and other invertebrate grazers decline. Overlying this broad-brush pattern are patches of crustose coralline algae (the Barrens habitat), the distributions of which are not clearly related to depth. Invertebrate herbivores, and sea urchins in particular, are abundant in the Barrens habitat. The Barrens habitat was most represented at the more southern locations. At the two most northern locations, reefs were shorter in length and dominated by ascidians (Pyura species).     

The effect of fire frequency on the sclerophyll vegetation of the West Head,New South Wales

The effect of fire frequency on the relative abundance of obligate-seeders and vegetative-regenerators was studied in 15 pairs of sites on the West Head, NSW. Each site pair consisted of a site which had been burnt frequently over the past 20 years and a nearby site which had been burnt less frequently. The data were collected in two phases. First, the relative abundance of the two overall groups of vegetative-regenerators and obligate-seeders was recorded by measuring the projective cover of live foliage. The presence or absence of particular species was then measured. For all the site pairs the projective cover of live foliage of obligate-seeders was dramatically less in the frequently burnt sites. Some obligate-seeder shrub species were absent from frequently burnt sites and the vegetation structure was simplified. In 11 of the 15 site pairs there was an increase in the projective cover of live foliage of vegetative-regenerators in the frequently burnt sites, while in the remaining four site pairs there were no significant differences between the infrequently and frequently burnt sites. Overall, the increases in the relative abundance of vegetative-regenerators made by high fire frequencies were not as large as the decreases in the relative abundance of obligate-seeders.     

Effects of fire and selective logging on the tree species composition of lowland dipterocarp forest in East Kalimantan, Indonesia

Tree species composition (diameter at breast height (dbh) 10 cm) was studied in primary, selectively logged and heavily burnt forests in East Kalimantan, Indonesia. The number of trees, tree species, and the Fishers's- diversity index were determined for the first 15 years (burnt forest) and 25 years (selectively logged forest) after disturbance. Additionally the population structure of six common and typical Macaranga pioneer tree species was compared through time between selectively logged, burnt and primary forest. Both selectively logged and burnt forest showed a significant reduction in number of trees and tree species per surface area directly after disturbance. Fire especially affected dominant tree species, while for selective logging the opposite was observed. In selectively logged forest the number of trees, tree species and the Fishers's- index reached pre-disturbance levels within c. 15 years. For burnt forest, only the number of trees recovered to pre-disturbance levels. The number of tree species stayed constant after disturbance, while the Fishers's- index decreased. The six studied Macaranga pioneer tree species seedlings were present in all forest types. Their density seems to be unrelated to light levels in the forest understorey but strongly related to the number of mature parent trees. Their sapling densities were strongly related to light levels in the forest understorey. The studied Macaranga species formed an important part of both under- and over-storey in burnt forest 15 years after disturbance, while they were almost absent in the understorey and only moderately common in the overstorey of selectively logged forest.     

Fungal endophyte communities in four Rhizophoraceae mangrove species on the south coast of China

This study investigated the taxonomic identities and diversity of fungal endophytes isolated from four Rhizophoraceae mangrove plant species, Ceriops tagal, Rhizophora apiculata, R. stylosa and Bruguiera sexangula var. rhynchopetala, using a combination of morphological and molecular approaches. Two hundred ninety-five isolates were classified into 38 taxa by morphological characteristics. The representative 38 isolates from each taxa were selected for further molecular identification using nuclear ribosomal DNA sequences, including both the internal transcribed spacers (ITS1 and ITS2) and the 5.8S gene region. The 38 representative endophytes were identified to various taxonomic levels. These results suggest that Pestalotiopsis and Phomopsis were the most frequent endophytes in the four host species. Some of the endophytes exhibit host and tissue specificity. The colonization frequencies of endophytic fungi in the stems of the four host plants are evidently higher than in the roots. The four Rhizophoraceae mangrove species have low similarities of endophyte communities.     

Patterns of tree species richness in relation to environment in southeastern New South Wales,Australia

Abstract We present regression models of species richness for total tree species, two growth forms, rainforest trees (broadleaf evergreens) and eucalypts (sclerophylls), and two large subgenera of Eucalyptus. The correlative models are based on a data set of 166 tree species from 7208 plots in an area of southeastern New South Wales, Australia. Eight environmental variables are used to model the patterns of species richness, four continuous variables (mean annual temperature, rainfall, radiation and plot size), plus four categorical factors (topographic position, lithology, soil nutrient level and rainfall seasonality). Generalized linear modelling with curvilinear and interaction terms, is used to derive the models. Each model shows a significant and differing response to the environmental predictors. Maximum species richness of eucalypts occurs at high temperatures, and intermediate rainfall and radiation conditions on ridges with aseasonal rainfall and intermediate nutrient levels. Maximum richness of rainforest species occurs at high temperatures, intermediate rainfall and low radiation in gullies with summer rainfall and high nutrient levels. The eucalypt subgenera models differ in ways consistent with experimental studies of habitat preferences of the subgenera. Curvilinear and interaction terms are necessary for adequate modelling. Patterns of richness vary widely with taxonomic rank and growth form. Any theories of species diversity should be consistent with these correlative models. The models are consistent with an available energy hypothesis based on actual evapotranspiration. We conclude that studies of species richness patterns should include local (e.g. soil nutrients, topographic position) and regional (e.g. mean annual temperature, annual rainfall) environmental variables before invoking concepts such as niche saturation.     

Mineralization of soil nitrogen in three forest communities from the New England region of New South Wales

Nitrogen (N) mineralization rates and the temperature response patterns of mineral N production in surface (0–7.6 cm) soils were compared in laboratory incubation studies based on disturbed, composite samples. Seasonal variation in the field levels of mineral N, and mineralization potential of intact (7.6 × 5.6 cm diameter) soil cores, were also investigated. Ammonification proceeded rapidly in each soil. Nitrification did not occur in grassy forest (GF) soil but was active in both layered forest (LF) and mossy forest (MF) soils, especially the former. Total mineral N production was greatest in MF and least in LF. Ammonification in disturbed samples was maximal at 50°C in all three soils with a secondary peak at 10°C in LF soil. Nitrification in LF and MF soils was most rapid at 25°C. Several species of ammonifying bacteria with different temperature optima were isolated, indicating that the process of ammonification is a composite of the activities of a variety of decomposer microbes. Mean field levels of mineral N and NH₄–N throughout the year were greatest in MF and least in LF. Seasonal fluctuations in NH₄–N were evident, concentrations being universally low in mid-winter (about 1.5 μgg^-1), increasing to a maximum in late summer (about 5 μg g^-1 in LF: 16–18 μg g^-1 in GF and MF). Field levels of NO₃–N were more constant and never more than 5 μg g^-1 in any community. Both total mineralization and ammonification in intact cores were greatest in MF and least in LF while nitrification was greatest in LF and almost negligible in GF, thus confirming the results obtained with disturbed samples. The potential for mineralization was large in mid-winter when the amount of mineral N was very low, and small in late summer when field levels were higher: this is interpreted as indicating that seasonal climatic factors regulate the availability of substrates for decomposers. Spatial variability in field levels of mineral N and mineral N production in the laboratory was evidenced by significant ‘sampling site’ effects in each community: however, at the sampling intensity used, the presence of bark mounds around Eucalyptus saligna trees could not be shown to affect these attributes. The inability of GF soil to nitrify when incubated in the laboratory could not be ascribed to a high C/N ratio, low pH, lack of substrate ammonium, or a low population of autotrophic nitrifying bacteria. No attempt was made to investigate the presence of allelopathic nitrification inhibitors. No evidence was obtained to support the view that nitrification is atypical of climax communities in situ. The most productive forest (LF) had the greatest capacity to nitrify and the least productive community (GF) the smallest capacity to do so.     

The impact on native mammals of land-use changes and exotic species in the Bega district,New South Wales,since settlement

Historical records for the Bega district were examined to chart the environmental changes wrought by Europeans through habitat alteration and the introduction of exotic species, and to interpret the impact of these on native mammals. Early recorded increases in native mammal populations, particularly koalas, may have been attributable to a decline in Aboriginal hunting pressure. After settlement in 1830, the valley forest was cleared progressively, ecosystems were altered by grazing and improved pastures, and many introduced plants became weeds in the disturbed environment. The timber industry exploited the forests of the valley and then the slopes of the surrounding mountains. Three exotic mammal species had a major impact on the district — hares, rabbits and foxes. Of the native fauna, the large and medium sized mammal species were those recorded most frequently. Dramatic fluctuations in numbers occurred in most of these species, and many reached plague proportions between 1880 and 1910, after which their numbers fell sharply. The peaks of exotic mammals and the decline of native mammals coincided with the clearing of the remaining forests in the Bega Valley. Many native mammal species are now rare, four are in danger of extinction, and at least six species have become locally extinct since settlement. As most of the native mammal populations in the district now occur in the State Forests surrounding the Bega Valley, the importance of preserving or managing these forests for wildlife must be weighed against proposals to manage the forests for pulpwood (woodchip) production.     

Bitou Bush control (after fire) in Bundjalung National Park on the New South Wales North Coast

Bitou Bush has already invaded extensive coastal dunes in subtropical and temperate eastern Australia. Can it be treated at a large enough scale to make a difference? Results to date of a targeted aerial spraying program (applied after wildfire at Bundjalung National Park) are showing strong recovery of high conservation value dunal vegetation along 35 km of the northern New South Wales coastline.      

Art,Culture and Ambiguity in Wilcannia,New South Wales

The claim of most town whites that Aboriginal people of Wilcannia make art but have no culture and the claim by Aboriginal people of the town that their art work and art designs demonstrate their culture and cultural traditions opens up the powerful and productive dimensions of art and culture for closer scrutiny. In so doing, the ambivalence and ambiguity which saturates these categories is ethnographically revealed. How can the presence and production of artworks in Wilcannia and the white denial of culture be considered? Why indeed do these questions matter, in what ways do they matter, and to whom do they matter? How do the categories of traditional/remote, urban/settled and their avatars intersect with black and white notions of Aboriginal art and Aboriginal culture discursively and experientially?     

Ecological association of habitats and bird species during the breeding season in southeastern New South Wales

Bird communities in southeastern New South Wales, as determined by classification and ordination techniques, were seldom discrete. The most cohesive assemblage was associated with wet sclerophyll and rainforest habitats. These moist forests also supported the richest avifaunas and had high population densities. Although most birds occurred throughout the region, most species were uncommon. Of the 116 species recorded, 51 (44%) were found on fewer than 10% of the 143 plots censused. Only 19 species occurred on more than half the plots, with six of these recorded on more than 90% of the plots. Other than a small group of birds primarily restricted to moist forest, only the most common and widely distributed species regularly occurred together. Species were grouped with habitats on an elevational gradient from coastal forests to the tablelands. Within this elevational range, species were associated with major structural features of the vegetation. In terms of bird assemblages, open habitats were distinguished from those with dense vegetation. Plots which had been recently logged were separated from mature forest. The results indicate that plans for wildlife management should consider both the assemblages of species which are associated with major forest habitats and the requirements of individual species.     

The association of tree species,landform, soils and erosion on Narrabeen sandstone west of Putty,New South Wales

An exploratory study was made of the tree species, landform, soils and erosional sequence along altitudinal transects from interfluve to stream channel in a valley incised into Narrabeen Group sandstones and shales to the west of Putty, NSW. Four groups of soils with similar edaphic features were identified. These ranged from duplex soils on the apparently old and stable valley rim, through eroded earths on zones of depletion and sandy regoliths with thick surface horizons on zones of accumulation, to mature duplex soils with thick surface horizons on the colluvial toeslopes. Four communities of tree species were found associated with the four groups of soils. A Eucalyptus punctata –E. piperita open-forest was found on the stable valley rim and a related Eucalyptus punctata –E. piperita – E. oblonga open-forest to low woodland was found on zones of depletion. An Angophora costata open-forest was found associated with the sandy regoliths on zones of accumulation and a Eucalyptus viminalis – E. tereticornis open-forest to tall open-forest occurred on thick soils of the colluvial waning slopes. It was found that the landform fitted a hypothetical nine unit land surface model. The soil types and plant communities were found to reflect the dominant contemporary pedogenetic and geomorphic processes which are also used to define the units of this model. Erosion was evident in the catchment, and the sequence of alluvial soils on the valley floor was found to be consistent with previous suggestions of widespread slope instability during the Quaternary period. Speculation is offered about the effects of management of the valley, especially in terms of land surface instability.     

Canopy damage to native vegetation on the central coast of New South Wales: Current status and detection of future changes

Abstract Canopy damage to coastal native vegetation was surveyed at Norah, Wybung and Wamberal Heads and at Little Beach on the central New South Wales coast in 1987. This preceded the commissioning of an ocean sewerage outfall at Norah Head in 1988, but postdated the commissioning of other outfalls in the region. Damage to the canopy of shrub species was assessed at the whole-plant level using a visual score. The method of scoring for canopy damage was tested for repeatability between observers; the average deviation between means was 5%, and the maximum deviation was 10% of the value of the mean. Mean per cent canopy damage scored for shrubs of various species at these sites ranged from negligible to very heavy. Comparison between sites and aspects was limited to Banksia integrifolia. Stands of this species on the southern side of Norah and Wybung Heads had approximately double the canopy damage of those on the northern side; this difference was significant. To confirm the patterns of damage seen at the whole-canopy level, the fate of tagged shoots of B. integrifolia was followed for 4 months. These shoots were also more damaged on the southern side than on the northern side of the two headlands. Analysis of wind speed and direction at Norah Head showed that the southern side of the headland received substantially more strong winds (>21 km h^?1) than the northern side. Airborne salt spray is known to be carried mainly in winds above this speed. In cases where 20 or more individuals of a species were found at a site, mathematical models relating the canopy damage of each plant to wind exposure, distance from the sea, and slope were investigated. Of 15 such cases, 13 significant models were found, with exposure being the major significant factor in accounting for variation in the data. Distance from the sea was only significant twice, and slope not at all. The pattern of damage, and its relationship to wind speed, direction, and exposure, are consistent with salt-spray being the major cause of leaf and shoot death at these sites. The sample sizes necessary to detect future changes of given magnitude to canopy damage were calculated.     

Myrmecochory in sclerophyll vegetation of the West Head,New South Wales

The incidence of myrmecochory (plants providing inducements for ants to disperse their seeds) was studied in thirty-eight plots on the West Head, New South Wales. The vegetation is made up of species from the temperate Australian flora which includes the largest known concentration of myrmecochores. Four plots with few myrmecochores either were frequently or permanently flooded, or were on fertile volcanic soil. Most plots were in well-drained sites on infertile sandstone. An average of 30% of the species on each of these were certainly myrmecochores, accounting for an average of 15% of the total cover. Within this majority of plots, the incidence of myrmecochory was not related to slope, aspect or vegetation structure. Although many myrmecochores were widespread in distribution, the majority did not contribute heavily to cover of the stands where they occurred.     

Saline lakes of the Paroo,inland New South Wales,Australia

Twenty-five lakes from fresh to crystallizing brine in the semi-desert of northwestern New South Wales, Australia, were studied regularly for 27 months. The lakes are small, shallow and ephemeral. Chemically waters are mainly of the NaCl type. Seventy-four species of invertebrate occur in saline waters (>3 g l^–1) with crustaceans such as Parartemia minuta, Apocyclops dengizicus, Daphniopsis queenslandensis, Diacypris spp. and Reticypris spp. dominant, particularly at higher salinities. The insects Tanytarsus barbitarsis and Berosus munitipennis are also important in meso- and hypersaline lakes. They are joined in hypo- and mesosaline waters by many others, including more beetles, odonatans, trichopterans, pyralids, notonectids, and corixids. Species richness declines with increasing salinity. There is a prominent inland faunal component mainly of crustaceans, including P. minuta, D. queenslandensis, R. walbu, Trigonocypris globulosa and Moina baylyi.     

Effects of height on the shore and complexity of habitat on abundances of amphipods on rocky shores in New South Wales, Australia

Patterns of abundance of epifaunal crustaceans were compared between two common brown algae in intertidal rock pools on a shore near Sydney, New South Wales, Australia. Amphipods were significantly more abundant on Sargassum globulariaefolium (which was most common low on the shore) than on Hormosira banksii (more common at mid-shore levels). Experiments tested the hypotheses that height on the shore and structural complexity of the algae were the main factors influencing patterns of abundance of amphipods. Reciprocal transplants using defaunated plants and similar experiments using artificial plants allowed simultaneous tests of these hypotheses. The abundance of a common intertidal amphipod, Sunampithoe graxon was significantly smaller on Sargassum transferred from low to mid-tidal level of the shore than on any other treatments, indicating that height on the shore affects numbers of this species. There were no Sunampithoe on Hormosira even when transplanted to low shore areas, indicating that other factors, apart from the height on the shore, are also important for this amphipod. Another common amphipod, Hyale maroubrae was generally found in greatest abundances on Hormosira transplanted from mid- to low shore and on Sargassum low on the shore, again indicating the importance of height on the shore. There was no difference in abundance of amphipods on ‘complex’ and ‘simple’ artificial plants indicating that structural complexity (as defined in this study) did not influence these amphipods.     

The vegetation of seacliffs and headlands in New South Wales,Australia

A phytosociological survey of seacliff and headland vegetation on the central and south coast of New South Wales was carried out. Analysis of the quadrat data led to the recognition of 15 communities; the occurrence of a number of other vegetation types is briefly discussed. The vegetation types fall into three major groupings: grasslands, scrub and heathland, although the coincidence between structural and floristic boundaries is poor. Ordination of the communities indicates that the major factors varying between communities are exposure and soil fertility, the grasslands and scrubs occurring on more fertile soils than the heathlands. Amongst the woody communities it is suggested that the two major groups recognized fall into different phytosociological alliances, although lack of studies of Australian vegetation limits the applicability of a conventional hierarchical classification. The true heathlands correspond closely with the alliance Leptospermion, previously recognized in Victoria. The scrub communities are assigned to a new alliance, the Westringio-Banksion integrifoliae.