The short-term responses of small mammals to wildfire in semiarid mallee shrubland, Australia

Context. Wildfire is a major driver of the structure and function of mallee eucalypt- and spinifex-dominated landscapes. Understanding how fire influences the distribution of biota in these fire-prone environments is essential for effective ecological and conservation-based management.

Aims. We aimed to (1) determine the effects of an extensive wildfire (118 000 ha) on a small mammal community in the mallee shrublands of semiarid Australia and (2) assess the hypothesis that the fire-response patterns of small mammals can be predicted by their life-history characteristics.

Methods. Small-mammal surveys were undertaken concurrently at 26 sites: once before the fire and on four occasions following the fire (including 14 sites that remained unburnt). We documented changes in small-mammal occurrence before and after the fire, and compared burnt and unburnt sites. In addition, key components of vegetation structure were assessed at each site.

Key results. Wildfire had a strong influence on vegetation structure and on the occurrence of small mammals. The mallee ningaui, Ningaui yvonneae, a dasyurid marsupial, showed a marked decline in the immediate post-fire environment, corresponding with a reduction in hummock-grass cover in recently burnt vegetation. Species richness of native small mammals was positively associated with unburnt vegetation, although some species showed no clear response to wildfire.

Conclusions. Our results are consistent with the contention that mammal responses to fire are associated with their known life-history traits. The species most strongly affected by wildfire, N. yvonneae, has the most specific habitat requirements and restricted life history of the small mammals in the study area. The only species positively associated with recently burnt vegetation, the introduced house mouse, Mus domesticus, has a flexible life history and non-specialised resource requirements.

Implications. Maintaining sources for recolonisation after large-scale wildfires will be vital to the conservation of native small mammals in mallee ecosystems.

Response of a shrubland mammal and reptile community to a history of landscape-scale wildfire

Fire plays a strong role in structuring fauna communities and the habitat available to them in fire-prone regions. Human-mediated increases in fire frequency and intensity threaten many animal species and understanding how these species respond to fire history and its associated effect on vegetation is essential to effective biodiversity management. We used a shrubland mammal and reptile community in semiarid south-western Australia as a model to investigate interactions between fire history, habitat structure and fauna habitat use. Of the 15 species analysed, five were most abundant in recently burnt habitat (8–13 years since last fire), four were most abundant in long unburnt areas (25–50 years) and six showed no response to fire history. Fauna responses to fire history were divergent both within and across taxonomic groups. Fire management that homogenises large areas of habitat through either fire exclusion or frequent burning may threaten species due to these diverse requirements, so careful management of fire may be needed to maximise habitat suitability across the landscape. When establishing fire management plans, we recommend that land managers exercise caution in adopting species-specific information from different locations and broad vegetation types. Information on animal responses to fire is best gained through experimental and adaptive management approaches at the local level.

Effects of fragmented habitat and fire on the distribution and ecology of the swamp antechinus (Antechinus minimus maritimus) in the Eastern Otways, Victoria

This study investigated the distribution, habitat and population dynamics of the swamp antechinus (Antechinus minimus maritimus) in the eastern Otway Ranges. The species has a restricted, disjunct distribution and has been recorded at 25 sites between 1969 and 1999. All sites were located within 7 km of the coast, occurred at altitudes up to 80 m above sea level and within 10 m of a gully. Analysis of landscape site variables identified sun index as being significant in determination of the probability of occurrence of A. minimus. The presence of A. minimus is negatively associated with sun index, occuring at sites that have a southerly aspect and gentle slope. A. minimus was located in a range of structural vegetation including Open Forest, Low Woodland, Shrubland and Hummock Grassland and a number of floristic groups, some characterised by high frequencies of sclerophyll shrubs, others by high frequencies of Pteridium esculentum, hummock grasses and herbaceous species. A. minimus occurs in fragmented, small populations with maximum population densities of 1.1–18 ha^–1. Populations at inland sites became extinct after the 1983 wildfire which burnt 41 000 ha. These sites have not been recolonised since, while on the coast the species did not re-establish until 1993–97. One population that is restricted to a narrow coastal strip of habitat is characterised by high levels of transient animals. The species is subject to extinction in the region due to habitat fragmentation, coastal developments and fire. Management actions to secure the present populations and ensure long-term survival of the species in the area are required and include implementation of appropriate fire regimes, prevention of habitat fragmentation, revegetation of habitat, and establishment of corridor habitat.

Habitat characteristics for New Holland mouse Pseudomys novaehollandiae in Victoria

Pseudomys novaehollandiae is 'Endangered' in Victoria, where it is presently considered to be extant at only three localities Loch Sport, Providence Ponds, and Wilsons Promontory. This study aimed to determine indicators of suitable habitat for the species that could assist in identifying potential habitat and sites for planned re-introductions as part of a recovery program. Vegetation and site data (soils, topography, rainfall, fire age-time since fire) were assessed at localities where P. novaehollandiae was recorded. The species occurred in five structural vegetation groups - open-forest, woodland, heathland, shrubland, grassland, with the most common being open-forest and woodland. Grassland and shmbland were restricted to coastal sand-dunes in south Gippsland. Understorey vegetation at most sites was dominated by sclerophyllous shrubs ranging in cover from 10 - 70%. Classification of quadrats produced eight floristic groups in which the trend was for quadrats to cluster according to geographical location. Ordination confirmed the classification pattern and vector-fitting produced significant correlations between vector points and five variables: species richness, latitude, longitude, fire age and annual rainfall. The study identified a range of vegetation communities where P. novaehollandiae occurs and provided evidence that the species is not restricted to floristically rich and diverse heathlands. The findings can be used to determine further localities with suitable habitat. However, factors other than vegetation are also likely to be important in predicting suitable habitat.

Pectinase production by solid fermentation from Aspergillus niger by a new prescription experiment

The Ordos Plateau in China is covered with up to 300,000 ha of peashrub (Caragana) which is the dominant natural vegetation and ideal for fodder production. To exploit peashrub fodder, it is crucially important to optimize the culture conditions, especially culture substrate to produce pectinase complex. In this study, a new prescription process was developed. The process, based on a uniform experimental design, first optimizes the solid substrate and second, after incubation, applies two different temperature treatments (30 °C for the first 30 h and 23°C for the second 42 h) in the fermentation process. A multivariate regression analysis is applied to a number of independent variables (water, wheat bran, rice dextrose, ammonium sulfate, and Tween 80) to develop a predictive model of pectinase activity. A second-degree polynomial model is developed which accounts for an excellent proportion of the explained variation (R² = 97:7%). Using unconstrained mathematical programming, an optimized substrate prescription for pectinase production is subsequently developed. The mathematical analysis revealed that the optimal formula for pectinase production from Aspergillus niger by solid fermentation under the conditions of natural aeration, natural substrate pH (about 6.5), and environmental humidity of 60% is rice dextrose 8%, wheat bran 24%, ammonium sulfate ((NH₄)₂SO₄) 6%, and water 61%. Tween 80 was found to have a negative effect on the production of pectinase in solid substrate. With this substrate prescription, pectinase produced by solid fermentation of A. niger reached 36.3 IU/(g DM). Goats fed on the pectinase complex obtain an incremental increase of 0:47 kg day^-1 during the initial 25 days of feeding, which is a very promising new feeding prospect for the local peashrub. It is concluded that the new formula may be very useful for the sustainable development of arid and semiarid pastures such as those of the Ordos Plateau.

Distribution and habitat preferences of the rufous bristlebird, Dasyornis broadbenti, in Portland, Victoria

The Rufous Bristlebird Dasyornis broadbenti is a ground-dwelling bird that is listed as nearthreatened (Lower Risk) in Victoria. The species has been observed in a variety of habitats ranging from thickets of shrubs in coastal gullies, shrubland and heathlands on limestone cliffs to sheltered gullies. This study aimed to assess the distribution and habitat preferences of a population of the species in Portland, southwest Victoria. Monthly surveys were conducted on foot in the study area for one hour following sunrise and one hour prior to sunset, and bird presence was recorded on the basis of calls and sightings. Observations outside of the survey times were also recorded to determine habitat utilisation. Vegetation floristics and structure and food availability were measured in areas where birds were present as well as surrounding areas where they were absent to determine habitat preferences. A population size of between 45 and 60 individuals was estimated in the 200ha study area. Bird presence was significantly positively correlated with increasing vegetation density. No significant associations were found between Rufous Bristlebird presence and the floristic associations. Although Rufous Bristlebirds occupy a variety of vegetation communities, results indicate that the key common factor appears to be structure of the vegetation. The findings of this study will be incorporated into a Geographic Information System to develop a spatial model of suitable habitat.

Spatial ecology of a root parasite : from pattern to process

Occurrence patterns of parasitic plants are constrained by the distribution of suitable hosts and movement patterns of seed vectors and, accordingly, represent a simplified system to study many aspects of spatial ecology and determinants of distribution. Previous work has focused on the aerially hemiparasitic mistletoes, and it is unclear whether root parasites are affected by similar factors. Here, we evaluate spatial patterns in the root parasitic Santalum lanceolatum in an arid shrubland in north-western New South Wales, central Australia. In this region, the principal host is a long-lived nitrogen fixing shrub Acacia tetragonophylla closely associated with ephemeral creek-lines. The location of 765 individuals of both species was mapped along a 250-m section of creek-line using a total survey station, and occurrence patterns of the root parasite related to host distribution and landscape context. We used Ripley's K-function and the O-ring statistic to determine whether the distribution of S. lanceolatum was random, aggregated or regular; the spatial scales at which these patterns occurred; and to quantify any spatial associations between the parasite and its host, A. tetragonophylla. While acacias were closely associated with the creek-line, S. lanceolatum plants were more tightly clustered, displaying significant clustering at two spatial scales (1.2 m and 8.8 m). We suggest that host quality may act as an important constraint, with only those acacias growing in or near the creek-line being physiologically capable of supporting a parasite to maturity. Insights gained from spatial analysis are used to guide ongoing research in this system, and highlight the utility of the O-ring statistic for understanding patterns of distribution affected by multiple processes operating at critical scales.

Lichen flora of the Mount Donna Buang Scenic Reserve, Victoria

This report investigated the lichen flora of the Mt Donna Buang Scenic Reserve in Victoria, There were several aims: to describe the lichens of the region, to produce a pictorial key enabling field identification and to determine any distribution patterns. A floristic survey covering approximately 50 square km was undertaken to determine lichen diversity of the region generally. Lichens were sampled along roads, tracks, walking trails and in sections of bush, taking into account forest type and, particularly, areas that were lichen rich. Seventy-five lichen species in 43 genera and 27 families were identified and described from the region. An unknown, species H, also was described. Of the 76 lichen species, 22 were crastose and the remainder macrolichens. The best represented families were: Cladoniaceae (8 species), Hypogymniaceae (6), Lobariaceae (7), Lecideaceae (6), Pannariaceae (6) and Parmeliaccae (6). This study described 12 species (17%) which previously were not known for Victoria and which are a first record for the state. These include: Cladonia sarmentosa (J.D. Hook & Taylor) Dodge, Graphis librata Knight, Parmelinopsis neodamaziana (Elix & Johnston) Elix & Hale, Pertusaria novaezelandiae Szatala, Placopsis pardlina f. microphylla Lamb, Porina leptalea AX. Sm., Pseudocyphellaria ardesiaca Galloway, Trapeliopsis congregant (Zahlbr.) Brako, Menegazzia myriotrema (Mull. Arg.) P. James, Bunodophoron scrobiculatum (Church. Bab,) Wedin, Parmelia testacea Stirton and Menegazzia purpurascens S. Louwhoff sp. nov.. The last eight species are new to the mainland and, apart from Menegazzia purpurascens, previously were known only from Tasmania. Five main elements of distribution were identified for the lichen flora of the Mt Donna Buang Scenic Reserve: cosmopolitan, austral/australasian, paleotropical, pantropical and western pacific. The majority of species (68%) had austral/australasian distributions, eleven (16%) were endemic to Australia and nine (13%) occurred only in Tasmania , Victoria and New Zealand. A pictorial, dichotomous key was constructed for the lichen flora of the Mt Donna Buang Scenic Reserve. Previously, keys to the lichen flora of Tasmanian rainforests were suggested as appropriate to similar areas in Victoria, however, the Victorian forests include a significant sclerophyll element The key presented is specific for the study site but is appropriate to similar regions in Victoria and has been tested in a number of these areas. The key was designed to be ‘user-friendly’ so that the experienced and inexperienced alike are able to use it. A more detailed investigation of the lichen flora of the Mt Donna Buang Scenic Reserve was carried out in order to determine distribution. A total of 50 quadrats, each 20m x 20m in size, were sampled. Within each, the dominant vegetation type was determined and individuals were identified and location noted. The cover abundance of each lichen species on each individual tree was estimated using a modified Braun-Blanquet scale. A total of 710 trees, representing 13 different species, were examined. Nothofagus cunninghamii (Hook.) Oerst, Eucalyptus regnans R Mull., Acacia dealbata Link, A. melanoxylon R. Br., Hedycarya angustifolia A. Cunn. and Atherosperma moschatum Labill. were the six most common tree species encountered at the study site. Nothofagus cunninghamii supported the greatest lichen diversity (39 species), although most species occurred on less than 10% of the trees. The majority of lichens occurring on N. cunninghamii A. melanoxylon, A. dealbata and H. angustifolia were foliose or crustose, those on Ł. regnans fruticose and foliose and those on A moschatum crustose. Bunodophoron australe was the only lichen species at the study site to occur on one host, Nothofagus cunninghamiL Many occurred on a number of different hosts, but were most common on one particular tree species. The distribution of lichens at the study site was analysed with a rnultivariate statistical package (PATN) which dealt with ‘pattern analysis’. The program ‘SSH’ in PATN which uses the Bray-Curtis ordination technique, was used to create scatterplots displaying the degree of dissimilarity between quadrats in terms of presence/absence of lichen species. The program ‘TWAY’ in PATN was used to construct a two way table to display which lichen species occurred in each vegetation type. The pattern analysis revealed that the lichens of the Mt Donna Buang Scenic Reserve were not restricted to any particular forest type, but particular lichens, or groups of lichens, tended to predominate in certain vegetation communities. This concurs with work done by others in Tasmanian forests. Quadrats which were situated in cool temperate rainforest were grouped more closely with each other than with quadrats in other vegetation types. These also supported the greatest number of lichen species. This was not surprising since N. cunninghamii the dominant tree species in cool temperate rainforest, supported the greatest lichen diversity.

Other communities : Box mistletoe (Amyema miquelii) parasitism is not detrimental to the health of grey box (Eucalyptus microcarpa) trees at a regional scale

Mistletoes are hemiparasites that occur worldwide in many types of forest, woodland and shrubland ecosystems (Watson 2001). Some species are regarded as pests due to their detrimental effects on host species (Hawksworth 1983; Reid & Yan 2000). Heavy infestations can affect the growth, productivity and form of host trees, and may cause host death (Reid et al. 1994; Shaw et al.2004, 2008). In south-eastern Australia, mistletoes often are visibly obvious in trees along roadsides, in paddocks and on the margins of open forests; and concerns have been expressed about their potentially detrimental effects on host trees.Despite this, little quantitative information is available on the effects of mistletoes on tree health and mortality (Reid et al. 1994). Are detrimental effects widespread or localized? A first step is to assess whether trees parasitized by mistletoe are less healthy than those without such parasites. Here, we investigate the relationship between parasitism by Box Mistletoe (Amyema miquelii (Lehm. ex Miq.) Tiegh.), a common species in south-eastern Australia, and the health of trees of a widespread host species, Grey Box (Eucalyptus microcarpa (Maiden) Maiden), across a large geographic region.

Effects of time since fire on birds : how informative are generalized fire response curves for conservation management?

Fire is both a widespread natural disturbance that affects the distribution of species and a tool that can be used to manage habitats for species. Knowledge of temporal changes in the occurrence of species after fire is essential for conservation management in fire-prone environments. Two key issues are: whether postfire responses of species are idiosyncratic or if multiple species show a limited number of similar responses; and whether such responses to time since fire can predict the occurrence of species across broad spatial scales. We examined the response of bird species to time since fire in semiarid shrubland in southeastern Australia using data from surveys at 499 sites representing a 100-year chronosequence. We used nonlinear regression to model the probability of occurrence of 30 species with time since fire in two vegetation types, and compared species' responses with generalized response shapes from the literature. The occurrence of 16 species was significantly influenced by time since fire: they displayed six main responses consistent with generalized response shapes. Of these 16 species, 15 occurred more frequently in mid- or later-successional vegetation (>20 years since fire), and only one species occurred more often in early succession (<5 years since fire). The models had reasonable predictive ability for eight species, some predictive ability for seven species, and were little better than random for one species. Bird species displayed a limited range of responses to time since fire; thus a small set of fire ages should allow the provision of habitat for most species. Postfire successional changes extend for decades and management of the age class distribution of vegetation will need to reflect this timescale. Response curves revealed important seral stages for species and highlighted the importance of mid- to late-successional vegetation (>20 years). Although time since fire clearly influences the distribution of numerous bird species, predictive models of the spatial distribution of species in fire-prone landscapes need to incorporate other factors in addition to time since fire.

Nurse plant effects of a dominant shrub (Duma florulenta) on understorey vegetation in a large, semi-arid wetland in relation to flood frequency and drying

 Questions: Do nurse plant interactions significantly influence understorey vegetation diversity in a large, semi-arid, shrub-dominated wetland? How do the modes and net effects of nurse plant interactions vary spatially along a flood frequency gradient, and temporally in response to drying? Location: Narran Lakes Ramsar site, New South Wales, Australia. Methods: Microhabitat characteristics, understorey vegetation and germinable soil seed banks were investigated in shrub and open habitats across a flood frequency gradient in a large, semi-arid wetland dominated by open shrubland under productive conditions following floodwater recession and again following 6 mo of drought. Split-plot ANOVA and multivariate analyses were used to determine the effects of shrubs on microhabitat character, understorey vegetation cover, species diversity, richness and composition and germinable soil seed banks. Results: Microhabitat characteristics, including canopy cover, litter cover and soil character, all differed between shrub and open habitats, especially in the most frequently flooded sites. Under productive conditions following flooding, lignum shrubs suppressed understorey vegetation cover but increased species richness at the site scale across the flood frequency gradient and, in the most frequently flooded sites, supported higher species density at a microhabitat scale. Under dry conditions, lignum shrubs had a positive effect on understorey vegetation cover, species richness and species density across the flood frequency gradient, but particularly in frequently flooded sites. A significant difference in soil seed bank composition between shrub and open habitats was only observed in frequently flooded sites. Conclusions: Nurse plant interactions appear to play an important role in determining understorey vegetation diversity in the lignum shrubland of the Narran Lakes wetland system. The modes and net effects of these nurse plant interactions vary in space and time in relation to flood history and drying. Positive interactions, probably involving microhabitat amelioration, appear to be particularly important to plant diversity and abundance under dry conditions. Under more favourable wetter conditions, lignum shrubs also contribute to understorey vegetation diversity by facilitating the establishment of different species than those dominating open habitats. Our findings have implications for the management of perennial shrubs and hydrological regimes in such wetlands.

Determinants of growth of the flammable grass, Triodia scariosa: consequences for fuel dynamics under climate change in the Mediterranean region of South Eastern Australia

Environmental conditions may influence the presence and strength of competitive interactions between different life forms, thereby shaping community composition and structure, and corresponding fuel dynamics. Woodland and shrubland communities of the Mediterranean climate region of South Eastern Australia contain a varied mixture of herbaceous and woody plants. The ratio of herbaceous to woody plants changes along gradients of temperature, moisture and soil fertility. This study aimed to experimentally examine the relative importance of, and interactions between environmental controls (moisture and soil fertility) on the balance of dominant herbaceous (Triodia scariosa) and woody plants (e.g. Acacia ligulata and Leptospermum coriaceum) and their ultimate effects on fuel and fire regimes. The results suggest that environmental determinants of the growth of T. scariosa are likely to be more important than interactions with shrubs in controlling the distribution of T. scariosa. The growth of T. scariosa was consistently higher under hot temperatures and on the less fertile yellow sands, which dominate the south of the region. The results suggest that there is strong potential for the distribution and abundance of T. scariosa to be altered in the future with changes in temperature associated with climate change. The distribution of soil types across the Mediterranean climate region of South Eastern Australia may be predisposed to favour the southerly expansion of T. scariosa-dominated communities in the future under a warmer climate.

Effects of long-term fire exclusion and frequent fire on plant community composition: a case study from semi-arid shrublands

Time since last fire and fire frequency are strong determinants of plant community composition in fire-prone landscapes. Our study aimed to establish the influence of time since last fire and fire frequency on plant community composition and diversity of a south-west Australian semi-arid shrubland. We employed a space-for-time approach using four fire age classes: 'young', 8-15years since last fire; 'medium', 16-34; 'old', 35-50; and 'very old', 51-100; and three fire frequency classes: burnt once, twice and three times within the last 50years. Species diversity was compared using one-way ANOVA and species composition using PERMANOVA. Soil and climatic variables were included as covariables to partition underlying environmental drivers. We found that time since last fire influenced species richness, diversity and composition. Specifically, we recorded a late successional transition from woody seeders to long-lived, arid-zone, resprouting shrub species. Fire frequency did not influence species richness and diversity but did influence species composition via a reduction in cover of longer-lived resprouter species - presumably because of a reduced ability to replenish epicormic buds and/or sufficient starch stores. The distinct floristic composition of old and very old habitat, and the vulnerability of these areas to wildfires, indicate that these areas are ecologically important and management should seek to preserve them.

Conserving long unburnt vegetation is important for bird species, guilds and diversity

Landscape-level wildfires have a major role in structuring faunal assemblages, particularly in fire-prone landscapes. These effects are mediated by changes to vegetation structure and composition that directly influence the availability of shelter, feeding and breeding resources. We investigated the response of a semi-arid shrubland bird community in Western Australia to the prevailing fire regime by examining the abundance, diversity and guild structure in relation to time since fire. We also examined vegetation structural attributes in relation to time since fire. We surveyed 32 sites ranging in age from 12 to 84 years since last fire. A total of 845 birds from 40 species were recorded. Vegetation structure varied with fire history with old and very old sites characterised by less bare ground, more leaf litter cover and greater canopy cover. Bird community composition varied with time since fire, driven by increased bird species richness and abundance of insectivores, granivores/frugivores, golden whistlers, grey shrike-thrush and red-capped robins with time since fire. Frequent, intense landscape-scale fires transform the landscape into homogeneous young shrublands, which may render vegetation unsuitable for several species and guilds.

Ecosystem responses to fire : identifying cross-taxa contrasts and complementarities to inform management strategies

Changes in fire frequency, extent, and intensity mean that understanding the effects of fire on plants and animals is a primary concern for ecologists and land managers. Given the potentially conflicting fire responses of species both within and across taxonomic groups, prescribing fire regimes based on the response of one or only a few species may have negative consequences for other species. Here, we integrate data collected from a series of independent but complementary studies spanning a 75 + year chronosequence in a semi-arid shrubland ecosystem in south-western Australia to consider how fire management can best promote biodiversity both within and across taxonomic groups (plants, birds, small mammals, and reptiles). Younger fire ages (6–14 years) contained sparse shrubs, large areas of bare ground, and lacked a distinct litter layer and canopy. The oldest vegetation (60–85 years) had a distinct canopy, a well-developed litter layer and cryptogamic crust, higher variability in patch width, and more woody debris. Plant species richness and diversity decreased with time since fire, whereas bird species richness and diversity increased with time since fire, and mammal and reptile species richness and diversity showed no trend. The composition of all four taxonomic groups varied according to time since fire and the presence of 11 species was confined above or below certain fire-age thresholds. Our results support the need to maintain a mix of both younger and older fire ages across the landscape to maximise species diversity, and highlight the particular importance of older fire ages for many species. Future fire management for biodiversity conservation will benefit from identifying and reconciling cross-taxa contrasts and complementarities.