Altered Fire Regimes Research Articles

Inselbergs in a changing world — global trends

Abstract. Based on a review of recent literature, this paper puts forward hypotheses for global trends of inselbergs (isolated mountains) with regard to: (a) their bioclimatic position in relation to the surroundings; (b) their potential for providing habitat niches; and (c) human impacts that may influence ecological processes. This review takes a landscape‐level perspective and highlights the challenges ahead in view of changing environmental conditions. Recognizing that inselbergs per se are composed of different microhabitats relative to their surroundings, inselbergs are hypothesized to be bioclimatic ‘islands’ of xeric conditions in a humid matrix in tropical and temperate regions, and ‘islands’ of mesic conditions in arid regions. The bioclimatic status of intermediate positions along this global axis (e.g. semiarid and subtropical savanna regions) is less clear. Here, other environmental variables may be of greater importance (microhabitat composition, size of inselberg, distance to other mountain habitats and biogeographical influences). Whether or not biotic communities match these hypothesized physical and bioclimatic trends warrants investigation and could contribute to explaining global species diversity patterns. Invasion of alien species in tropical and Mediterranean‐climate regions, and altered fire regimes and resource use pose threats to inselberg communities. Their role as sources of native species to recolonize disturbed surroundings is important in degraded semiarid and arid regions. A generalized model is proposed hypothesizing possible processes between inselberg habitats and disturbed areas in their surroundings in different climatic regions. This model may help to direct further research towards substantiating these perceived trends.

Historical changes in the bird fauna at Coomooboolaroo, northeastern Australia, from the early years of pastoral settlement (1873) to 1999

Across most of northern Australia, the historical record is generally insufficient to serve as a baseline for interpreting the impacts of European settlement on fauna. A notable exception is the pastoral property Coomoobolaroo (454 km 2) in central Queensland, where the ornithologist Charles Barnard maintained a detailed record of bird fauna from 1873 to 1933. We re-surveyed the property in 1999, and collated other information on its current avifauna, giving 242 species in total recorded over the period 1873–1999 (of which we had sufficient information to ascribe trends to 200 species). The bird fauna of Coomooboolaroo has undergone substantial change, across both of the periods 1873–1933 and 1934–1999. From 1873 to 1999, 45% of species declined or were lost from the property, compared with 13% of species that either colonised the property or increased. Most of the latter are widespread species or those known to benefit from clearing and land development. This extent of change appears at least as high as that reported for most comparable studies elsewhere in Australia, despite these being conducted at sites that have been subjected to superficially greater environmental degradation. The greatest rates of loss occurred among birds associated with softwood scrub (dry rainforest), grasslands and swamps. Smaller species were more susceptible to decline, but change in status was not significantly associated with foraging style nor different between residents and migrants. Many of the species that have declined at Coomooboolaroo have also declined in many other geographic regions, habitats and land-uses. Change in status at this property can be attributed to diverse factors, including changes in predation pressures; environmental change due to altered fire regimes and/or grazing by livestock; and vegetation clearance at both property and regional scales. The multiplicity and complex interrelationships of such factors renders it difficult to predict assemblage-level change.

A late-Holocene charcoal record from Lake Masoko, SW Tanzania: climatic and anthropologic implications

Charcoal analysis from a short core in a small tropical crater lake (Lake Masoko, SW Tanzania) reveals changes in charred-particle deposition and properties, consistent with high climatic variability for the last 4200 years. This is evidenced by automated image analysis of charcoal size distributions, thermal resistant carbon (soot) and black carbon elemental analysis. Charcoal-particle transport in the lake decreases during dry spells, and increases with stronger runoff regime in the catchment area under humid periods and/or during abrupt low-stands of the lake. However, between 1830 and 1560 cal. yr BP, charcoal-distribution variability and an abrupt increase in particulate carbonaceous particles testify to regional emissions from forest fires and atmospheric transport. This event was followed by a prolonged period of material accumulation but regional climatic drying. After 1560 cal. yr BP, large charcoal fragment accumulation and a rise in the length:width ratio of microcharcoal indicate fires closer to the lake and the opening of the local woodland. These new data give evidence of large-scale fire development just prior to a pollen-inferred vegetation change and late Iron Age activity in the area, which probably coincide with an altered fire regime. In fact, charcoal-size distribution and particulate carbon elemental analysis constrain the sources of fossil carbonaceous particles, and provide an accurate proxy of fire and climatic change in southern tropical Africa.

Simulating the effects of future fire regimes on western Canadian boreal forests

Abstract. Effects of future fire regimes on boreal tree species and plant functional types were studied in W Canada using a simulation approach. Present (1975–1990) and future (2080–2100) fire regimes were simulated using data from the Canadian Global Coupled Model (CGCM1). The long‐term effects of these fire regimes were simulated using a stand level, boreal fire effects model (BORFIRE) developed for this study. Changes in forest composition and biomass storage due to future altered fire regimes were determined by comparing the effects of present and future fire regimes on forest stands over a 400‐yr period. Differences in the two scenarios after 400 yr indicate shifting trends in forest composition and biomass that can be expected as a result of future changes in the fire regime. The ecological impacts of altered fire regimes are discussed in terms of general plant functional types. The Canadian Global Coupled Model showed more severe burning conditions under future fire regimes including fires with greater intensity, greater depth of burn and greater total fuel consumption. Shorter fire cycles estimated for the future generally favoured species which resprout (fire endurers) or store seed (fire evaders). Species with no direct fire survival traits (fire avoiders) declined under shorter fire cycles. The moderately thick barked trait of fire resisters provided little additional advantage in crown fire dominated boreal forests. Many species represent PFTs with multiple fire survival traits. The fire evader and avoider PFT was adaptable to the widest range of fire cycles. There was a general increase in biomass storage under the simulated future fire regimes caused by a shift in species composition towards fast‐growing re‐sprouting species. Long‐term biomass storage was lower in fire exclusion simulations because some stands were unable to reproduce in the absence of fire.

Simulating the effects of future fire regimes on western Canadian boreal forests

Abstract Effects of future fire regimes on boreal tree species and plant functional types were studied in W Canada using a simulation approach. Present (1975–1990) and future (2080–2100) fire regimes were simulated using data from the Canadian Global Coupled Model (CGCM1). The long-term effects of these fire regimes were simulated using a stand level, boreal fire effects model (BORFIRE) developed for this study. Changes in forest composition and biomass storage due to future altered fire regimes were determined by comparing the effects of present and future fire regimes on forest stands over a 400-yr period. Differences in the two scenarios after 400 yr indicate shifting trends in forest composition and biomass that can be expected as a result of future changes in the fire regime. The ecological impacts of altered fire regimes are discussed in terms of general plant functional types. The Canadian Global Coupled Model showed more severe burning conditions under future fire regimes including fires with grea...

A Comparison of Presettlement and Present-day Forests in Northeastern Lower Michigan

General Land Office survey records of 1838–1846 were used to reconstruct the pre-European settlement vegetation along a soil moisture gradient in the Huron National Forest of northeastern lower Michigan. These data were compared to current forest data. Jack pine (Pinus banksiana), red pine (P. resinosa) and white pine (P. strobus) dominated fire-prone presettlement dry and dry-mesic sites on coarse-textured soils of glacial outwash plains and moraines. Hemlock (Tsuga canadensis), beech (Fagus grandifolia), sugar maple (Acer saccharum) and white pine were most important on presettlement mesic sites on medium-textured soils of moraines and kame and kettle topography. Presettlement wet-mesic sites were dominated by hemlock, white pine and aspen (Populus spp.). White cedar (Thuja occidentalis) and tamarack (Larix laricina) dominated presettlement wet sites on organic soils of outwash plains. Important presettlement forest types included: jack pine (41%), mixed conifer–northern hardwood (22%), lowland conifer (15%) and mixed pine (14%).Tree species composition has substantially changed on dry-mesic to wet-mesic sites over the last 150 y. White pine and hemlock have significantly declined in abundance. Oak (Quercus spp.), sugar maple and aspen currently dominate dry-mesic to wet-mesic sites. Important current forest types include: jack pine (32%), aspen–white birch (Betula papyrifera; 16%), oak (16%) and northern hardwood (8%). Today's forests have smaller trees and higher tree densities than forests in the presettlement era. Widespread logging, altered fire regimes and other anthropogenic disturbances since European settlement have interacted with physical factors to produce today's forests.

Spatial modelling of "alternative" future landscapes under climate change and fire suppression, Mont Do, New Caledonia

The vegetation dynamics and disturbance regimes of the south-west Pacific have been significantly altered following human settlement. Previously forested landscapes are now dominated by a matrix of flammable early successional vegetation within which patches of mesic, fire-sensitive forest are embedded. Future environmental change, and in particular climate change, will further affect disturbance regimes in these ecosystems. If ignition frequency and fire extent increase, then the persistence of these landscapes in their current composition and structure is uncertain. Using a spatially explicit landscape ecological model, we explored the implications of climatically altered fire regimes for landscape composition and structure in a mountain-top reserve in New Caledonia. The outcomes of the modeling suggest that increased ignition probability and vegetation flammability would lead to a maquis (heathland)-dominated landscape structurally simpler than that seen today. The feasibility of fire suppression as a means of managing altered fire regimes was explored using a series of model experiments. Fire suppression has been problematic in some systems, especially those where fire hazard increases over time. However, in this ecosystem, and others in the south-west Pacific, it may be a viable alternative for managing fire because fire hazard, in terms of flammability, peaks early in the succession and then decreases over successional time.

Phosphorus addition reduces invasion of a longleaf pine savanna (Southeastern USA) by a non-indigenous grass (Imperata cylindrica)

Imperata cylindrica is an invasive C4 grass, native to Asia and increasing in frequency throughout the tropics, subtropics, and southeastern USA. Such increases are associated with reduced biodiversity, altered fire regimes, and a more intense competitive environment for commercially important species. We measured rates of clonal spread by I. cylindrica from a roadside edge into the interior of two longleaf pine savannas. In addition, we measured the effects of fertilization with nitrogen and phosphorus on clonal invasion of one of these sites. Clonal invasion occurred at both sites and at similar rates. Older portions of an I. cylindrica sward contained fewer species of native pine-savanna plants. Clonal growth rates and aboveground mass of I. cylindrica were reduced by the addition of phosphorus relative to controls by the second growing season at one site. As a group, native species were not affected much by P-addition, although the height of legumes was increased by P addition, and the percent cover of legumes relative to native non-legumes decreased with increasing expected P limitation (i.e., going from P-fertilized to controls to N-fertilized treatments). Clonal invasion was negatively correlated with the relative abundance of legumes in control plots but not in P-fertilized plots. Species richness and percent cover of native plants (both legumes and non-legumes) were dramatically lower in N-fertilized plots than in controls or P-fertilized plots. Species richness of native plants was negatively correlated with final aboveground mass of I. cylindrica in control and P-fertilized plots, but not in N-fertilized plots. The results suggest that I. cylindrica is a better competitor for phosphorus than are native pine-savanna plants, especially legumes, and that short-lived, high-level pulses of phosphorus addition reduce this competitive advantage without negatively affecting native plant diversity. Ratios of soil P to N or native legume to non-legume plant species may provide indicators of the resistance of pristine pine savannas to clonal invasion by I. cylindrica.

Modelling strategies for the management of the critically endangered Carpentarian rock-rat (Zyzomys palatalis) of northern Australia

The Carpentarian rock-rat (Zyzomys palatalis) is a critically endangered endemic rodent known from only four sandstone gorges in the southeast Gulf of Carpentaria, Northern Territory, Australia. These gorges harbour thickets of monsoon rainforest and broadleaf woodland, surrounded by a Eucalypt savanna matrix. The long-term persistence of Z. palatalis is threatened by altered fire regimes, grazing by feral animals and stock, weed intrusion, and the stochastic hazards associated with small, fragmented populations. To assess the relative importance of these threats and develop practical management options, a population and habitat simulation model was developed, based on the best existing data. Population viability was predicted to be highly sensitive to the frequency of hot, late dry-season fires. Progressive habitat degradation (due predominantly to intense late dry-season fires) is likely to substantially reduce population size and lead to the probable extinction of the species within the next 100 years. The most effective management strategy to counteract this threat would be regular, controlled, fuel reduction burns in the vegetation around the gorge entrances during the early dry season. Establishing a new population (through translocation of captive-bred individuals) would not appreciably reduce extinction risk, but could provide valuable additional data on the impact of threats, if conducted as an adaptive management experiment.

Growth and carbon stock change in eucalypt woodlands in northeast Australia: ecological and greenhouse sink implications

AbstractData from 57 permanent monitoring sites are used to document the growth in woody vegetation and estimate the carbon sink in 27 M ha of eucalypt woodlands (savannas), contained within c. 60 M ha of grazed woodlands in Queensland (northeast Australia). The study sites are shown to be representative of the environment and structure of the eucalypt woodlands in the defined study area. Mean basal area increment for all live woody plants in 30 long‐term sites, with an average initial basal area of 11.86 ± 1.38 (SE) m2 ha−1, was 1.06 m2 ha−1 over a mean 14 years timeframe. The majority of the measurement period, commencing between 1982 and 1988, was characterized by below‐average rainfall. The increase in live tree basal area was due primarily to growth of existing trees (3.12 m2 ha−1) rather than establishment of new plants (0.25 m2 ha−1) and was partly offset by death (2.31 m2 ha−1). A simple but robust relationship between stand basal area and stand biomass of all woody species was developed for the eucalypt dominant woodlands. Analysis of above‐ground carbon stocks in live and standing dead woody plants gave a mean net above‐ground annual carbon increment for all 57 sites of 0.53 t C ha−1 y−1, similar to values estimated elsewhere in world savannas. Published root : shoot ratios were used to infer C flux in woody root systems on these sites. This results in an estimated sink in above‐ and below‐ground biomass of 18 Mt C y−1 over the eucalypt woodlands studied, and potentially up to 35 Mt C y−1 if extended to all grazed woodlands in Queensland. It is suggested that introduction of livestock grazing and altered fire regimes have triggered the change in tree‐grass dominance in these woodlands. Thus, change in carbon stocks in the grazed woodlands of Queensland is identified as an important component of human‐induced greenhouse gas flux in Australia, equivalent in magnitude to c. 25% of the most recently published (1999) total estimated national net emissions. The latter inventory takes into account emissions from land clearing, but does not include the sink identified in the present study. This sequestration also represents a small but significant contribution to the global terrestrial carbon sink.

Effects of Prescribed Fire on Shinnery Oak ( Quercus havardii) Plant Communities in Western Oklahoma

AbstractChanges in structural and compositional attributes of shinnery oak (Quercus havardii Rydb.) plant communities have occurred in the twentieth century. These changes may in part relate to altered fire regimes. Our objective was to document effects of prescribed fire in fall (October), winter (February), and spring (April) on plant composition. Three study sites were located in western Oklahoma; each contained 12, 60 × 30‐m plots that were designated, within site, to be seasonally burned, annually burned, or left unburned. Growing season canopy cover for herbaceous and woody species was estimated in 1997–1998 (post‐treatment). At one year post‐fire, burning in any season reduced shrub cover, and spring burns reduced cover most. Winter and annual fires increased cover of rhizomatous tallgrasses, whereas burning in any season decreased little bluestem cover. Perennial forbs increased with fall and winter fire. Shrub stem density increased with fire in any season. Communities returned rapidly to pre‐burn composition with increasing time since fire. Fire effects on herbaceous vegetation appear to be manifested through increases in bare ground and reduction of overstory shrub dominance. Prescribed fire can be used as a tool in restoration efforts to increase or maintain within and between community plant diversity. Our data suggest that some plant species may require or benefit from fire in specific seasons. Additional research is needed to determine the long‐term effects of repeated fire over time.

Terrestrial arthropods in a fragmented landscape: a review of ecological research in the Western Australian central wheatbelt

In 1985, CSIRO's Wildlife and Ecology established ''The Kelierberrin Project on Fragmented Landscapes", a study to investigate the role of remnant vegetation in sustaining the native biota in Western Australia's central wheatbelt. This paper reviews findings, and other relevant research within the wheatbelt region, with regard to the terrestrial arthropod fauna. We examine critical issues for faunal persistence with regard to disturbance effects on the biota (habitat fragmentation effects of remnant size and spatial isolation (connectivity), livestock and associated exotic weed invasion, altered fire regimes, changes in hydrology, and recolonization of restored habitat), indicators of arthropod species richness at the individual remnant scale, and endemism and taxonomic richness. We provide management recommendations for the conservation of terrestrial arthropods in the Western Australian central wheatbelt and suggest priority research.

The Effects of Climatically Altered Fire Regimes on Initial Successional Responses in Yellowstone National Park

Many scientists predict that due to the quick response of fire regimes to changes in climate (Flannigan et al. 1998; Stocks et al. 1998), the most rapid and extensive effects of climate change will be mediated by altered disturbance regimes (Davis and Botkin 1985; Franklin et al. 1992; Graham et al. 1990; Weber and Flannigan 1997). Under climate scenarios expected for C02 doubling, Price and Rind (1994) predict a 44% increase in lightning-caused fires and a 78% increase in total area burned for the U.S. Although regional climate scenarios are still subject to a fairly high degree of uncertainty, regional predictions for Yellowstone National Park (YNP) estimate an increase in aridity (Balling et al. 1992) and mean July temperatures (Bartlein et al. 1997), suggesting that fire frequencies could significantly increase in YNP over the next century. While several models have simulated the response of western coniferous forests to altered fire regimes (Baker et al. 1991; Gardner et al. 1996; Keane et al. 1990; Keane et al. 1995; Romme and Turner 1991), little empirical work on the successional responses to different intervals of stand­replacing fire has been incorporated, and remains a critical element in predicting the effects of climatically altered disturbance regimes in forested landscapes. Previous work in Yellowstone has considered the effects of fire severity, fire size and level of serotiny in explaining initial pathways of postfrre succession across the Yellowstone landscape (Turner et al. 1994; Turner et al. 1997). The effects of the third component of the disturbance regime, fire interval, remains largely unexplored, and represents a fundamental link in predicting potential effects of climate change on the Yellowstone landscape. The specific objectives of our research, therefore, were to assess: Are there a significantly different successional responses following different intervals of stand-replacing fire in Yellowstone National Park? Because serotiny exerts a strong influence on initial post-fire succession in Yellowstone (characterized by variation in lodgepole pine densities), we also sought to track stand-level changes in serotiny over time. In order to flesh out a possible mechanism for why postfrre succession may vary depending upon the age at which the stand burns we asked: What is the temporal variation in lodgepole pine serotiny within the park?

Comment-Reverse cumulative standing age distributions in fire-frequency analysis

Fire-frequency (FF) analysis is used to derive, from empirical data, parameters that describe the frequency of fires in a system; the time-since-fire distribution; the age-specific probability of fire; and other summary statistics such as the natural fire rotation, the mean fire-return interval, and the fire cycle (Heinselman 1973, 1981; Romme 1981; Agee 1993; Johnson and Gutsell 1994). Results of FF analyses have been used to identify changes in conditions affecting fires in the past (Heinselman 1973; Alexander 1980; Stokes and Dieterich 1981; Hemstrom and Franklin 1982; Mastrogiuseppe et al. 1983; Johnson et al. 1990; Johnson and Larsen 1991; McCune 1983; Romme 1982; Swetnam 1993), to model landscapes produced by natural or altered fire regimes (Baker 1992), and to predict the amount of old forests expected in natural fire-dominated landscapes (B.C. Ministry of Forests and B.C. Environment 1995; Johnson et al. 1995; Martell 1995; Lesica 1996). The ecosystem-management paradigm of mimicking natural disturbances in managed ecosystems (Hunter 1993; Grumbine 1994) or containing the effects of management within the range of natural disturbances (Attiwill 1994) has recently increased the influence of FF models in informing planning decisions in forest management (Mutch et al. 1993; B.C. Ministry of Forests and B.C. Environment 1995) and in protected areas management (Brown et al. 1995). Unfortunately, a common method of applying empirical data on stand ages to FF analysis is incorrect, producing incorrect results and interpretations in published studies. We demonstrate the mistake by examining the derivation of FF models, comparing them to their analogue in population ecology, static life-table (SLT) analyses.

Western Juniper Expansion on Adjacent Disturbed and Near-Relict Sites

We determined rates of western juniper (Juniperus occidentalis spp. occidentalis Hook.) density and cover change during the period 1951 to 1994 at 3 adjacent sites with nearly identical elevation, slope, aspect, soils, plant communities, and climate, but different land-use histories. The 3 sites are located in central Oregon at the confluence of the Deschutes and Crooked Rivers. Two of the sites are typical of central Oregon rangelands in that they have a history of anthropogenic disturbance including active fire suppression and domestic livestock grazing. The third site is a relict mesa that is a protected Research Natural Area and has experienced minimal anthropogenic impacts. We used large scale aerial photography to determine cover and density of western juniper in 1951, 1956, 1961, 1972, 1982, and 1994. We found that western juniper density and cover during the last 4 decades increased at all sites, with changes on the relict site similar to those on one of the disturbed sites. We suggest that even though 2 of the traditionally cited causes of western juniper expansion since the late 1800s (altered fire regimes, domestic livestock grazing) may have contributed to expansion on our disturbed sites, these mechanisms can not explain expansion on the near-relict mesa. Further, we examined climatic changes since 1900 in the region and concluded that the data did not fully support a climate-driven mechanism for the expansion. In seeking to explain western juniper expansion on semiarid rangelands, we suggest that all potential causal mechanisms (e.g., fire history, biological inertia, climate, domestic grazing, atmospheric CO2 enrichment) be considered.

Responses of Australian Mammals to Disturbance: A Review.

The Australian native mammal fauna has evolved in an environment where 'natural' or endogenous disturbance is ongoing and widespread, be it fire, flood, drought or cyclones. Since European settlement, however, the type, scale, frequency and intensity of disturbance has changed and added a new suite of exogenous impacts including introduced predators and herbivores, vegetation clearance, habitat fragmentation, altered fire regimes, grazing and timber harvesting. This has presented novel and significant adaptive challenges to native mammals over a compressed time-scale, resulting in major extinctions, population declines and disruption to community structure. In this paper we examine the ecology of Australian mammals in the context of these new disturbances, and compare the response patterns observed, and assess the processes operating. In general, Australian mammalian successional patterns are closely tied to vegetation regeneration, which is related to the degree of disruption. Disturbances such as predation do not fall within this pattern. Mammalian successional states vary between different disturbance types within an ecosystem, depending on the critical elements of vegetation structure and composition. Landscape and climatic factors also affect successional patterns and need to be further investigated.

Canadian boreal forest ecosystem structure and function in a changing climate: impact on fire regimes

Boreal forest fire regime, which encompasses fire intensity, frequency, seasonality, size, type (crown versus surface), and severity (depth of burn), is an organizing factor of boreal forest landscapes and highly dependant on climate. This review combines what is known about boreal forest dynamics from paleological studies, with the information derived from state-of-the-art climate and vegetation modeling, to present possible scenarios of the impact of anticipated climate change on boreal forest ecosystem structure and function, particularly in relation to fire regimes. Anticipated climatic/atmospheric impact on plant physiological, communal, ecosystem, and finally landscape-level interactions with fire are reviewed. All indications from the modeling sector point towards unprecedented increased regional or seasonal temperatures, with projected changes most pronounced at high latitudes and there greatest in winter. Anticipated climate change scenarios are expected to alter dramatically the boreal forest ecosystems and fire regimes with which they are currently in equilibrium. Changed fire regimes could be represented by increased annual area burned because of an extended fire season, increased fire frequency, and severity. Simulation studies show the potential for greatly reduced boreal forest area and increased fragmentation due to climate change. Fire regime as an ecosystem process is highly sensitive to climate change because fire behaviour responds immediately to fuel moisture, which is affected by precipitation, relative humidity, air temperature, and wind speed. This interaction between climate change and fire regime has the potential to overshadow the importance of the direct effects of global warming on species distribution, migration, substitution, and extinction. Such a scenario suggests that rate and magnitude of fire-regime-induced changes to the boreal forest landscape could greatly exceed anything expected due to atmospheric warming alone. Socioeconomic implications of altered fire regimes in a changing climate are discussed in terms of adaptive fire management strategies, age class distribution, and such global stewardship issues as biodiversity, carbon cycling, and sequestration.

The natural grasslands of Cape York Peninsula, Australia. Description, distribution and conservation status

The grasslands of Cape York Peninsula in monsoonal north Queensland, Australia represent extensive examples of this formation that have been relatively undisturbed by agricultural development. Fourteen grassland units are mapped on the basis of their relationship to soils and landforms. Nine grassland communities were derived from a floristic analysis of the site data, and are related to the mapping units. Half of the grassland map units have less than 10% of their area protected in conservation reserves. The annual forb sickle pod Senna obtusifolia is considered to be the most serious exotic weed at present, because it dominates large areas of unreserved Imperata cylindrica grassland, a community that does not occur extensively elsewhere in Australia. Wetland exotic grasses that are being actively promoted for agriculture pose a potential threat to the Oryza grasslands that occur over large areas of the seasonally flooded coastal plains. It is recommended that further exotic pasture species should not be grown on Cape York Peninsula unless their containment can be assured. Some grasslands appear to be maintained by fire. Data are provided that demonstrate the conversion of some grassland types to woodlands in the last 30 years, and it seems probable that the change is a result of altered fire regimes. Even if adequately reserved, appropriate fire management is required to maintain the grasslands of Cape York Peninsula.

Temperate Eucalypt Woodlands: a Review of Their Status, Processes Threatening Their Persistence and Techniques for Restoration

Temperate eucalypt woodlands were once widespread throughout southern Australia and Tasmania. Following European settlement, woodlands were cleared for agriculture, or grazed and converted to pasture. In the wheatbelts of south-western and south-eastern Australia, woodlands have been almost completely eliminated from the landscape with as little as 3% of some woodland types remaining. As a consequence, some temperate eucalypt woodland communities are amongst the most poorly conserved ecosystems in Australia. The main effect of widespread clearing and grazing has been the loss of habitat. This has had a devastating impact on the woodland flora and fauna. A number of species have become extinct and many are threatened; many others have undergone regional and local population declines. Woodlands now occur throughout much of their former range as remnants of varying size, quality and isolation. Many of these are under threat from further clearing, rising saline water tables and increased inundation, livestock grazing, nutrient enrichment, soil structural decline, altered fire regimes and the invasion of exotic weeds. The degradation and loss of biodiversity in temperate eucalypt woodlands will continue unless clearing stops and the management of remnants changes; this will invariably involve ecological restoration both at the patch and landscape level. The review discusses approaches to restoration and reveals that there are few data in the published literature describing techniques for reversing degrading processes and restoring diversity structure and function in remnant woodlands. This information is urgently needed. Past research on temperate eucalypt woodlands has focused on identifying the processes of degradation and these are now relatively well documented. There is a need to shift the focus of research to developing solutions for these problems.

The Distribution and Status of The New Holland Mouse, Pseudomys novaehollandiae (Waterhouse 1843) In Victoria.

The New Holland Mouse (Pseudomys novaehollandiae) is an endangered species in Victoria. The aims of this study were to determine the present distribution of the species and to identify processes and habitat modification that threaten the species future status. Survey trapping was carried out in areas where P. novaehollandiae had been recorded previously. The species is in a demonstrable state of decline, and there is evidence that it has been lost from at least three and possibly six localities in the past 10-16 years. The species decline appears to have resulted from a combination of systematic factors, the most important of which is habitat loss due to clearing of native vegetation, and the subsequent fragmentation of populations. Altered fire regimes and the consequent changes to the productivity of vegetation and the diet of the species are also likely to be important factors. The areas where P. novaehollandiae remains extant Anglesea, Loch Sport, Providence Ponds, Wilson's Promontory and possibly Mullungdung now assume much greater importance. Critical habitat should be identified and managed. While research questions concerning the population dynamics of the species and threats to its survival remain unanswered, management actions are required immediately. These include monitoring known populations, ensuring protection of habitats, identifying potential habitat and determining suitable management regimes.