Immediate and short‐term responses of bird and mammal assemblages to a subalpine wildfire in the Snowy Mountains,Australia

Abstract Over 35 days in January–February 2003, wildfires burnt across much of the subalpine/alpine landscape of south‐eastern Australia, including about 70% of the land above 1500 m in the Snowy Mountains. At the time of the fire, studies of two subalpine faunal assemblages were being undertaken. The opportunity to resurvey the assemblages was taken in order to examine the immediate impact of fire in an environment where it is uncommon but predicted to occur increasingly with global warming. A study area in the Whites River Valley, where the number of bird species was counted monthly from 1996 to 2003, and weekly in late winter–spring from 2000 to 2003, was burnt in one fire. As well as the expected decrease in the number of individual birds, the fire resulted in an immediate decrease in the number of bird species, unlike in previously studied montane forest, with only the regularly wintering species plus the olive whistler and the ground‐feeding flame robin remaining. During the post‐winter avian immigration, few regular spring migrants appeared on burnt sites despite their nearby presence on the unburnt side of the valley. Five of six small mammal trapping grids were burnt. As with fires at lower altitudes, there was an immediate reduction in mammal numbers on burnt grids following the fire, but in addition, one species, Mastacomys fuscus, declined further in the ensuing 2 months both on burnt and unburnt sites. Numbers of Antechinus swainsonii and Rattus fuscipes stabilized until autumn/winter when there was a further decline due to the unavailability of subnivean space to allow winter foraging, allied with a concentration of fox predation on areas still carrying populations of small mammals.     

Post‐fire recovery of revegetated woodland communities in south‐eastern Australia

The primary goal of restoration is to create self‐sustaining ecological communities that are resilient to periodic disturbance. Currently, little is known about how restored communities respond to disturbance events such as fire and how this response compares to remnant vegetation. Following the 2003 fires in south‐eastern Australia we examined the post‐fire response of revegetation plantings and compared this to remnant vegetation. Ten burnt and 10 unburnt (control) sites were assessed for each of three types of vegetation (direct seeding revegetation, revegetation using nursery seedlings (tubestock) and remnant woodland). Sixty sampling sites were surveyed 6 months after fire to quantify the initial survival of mid‐ and overstorey plant species in each type of vegetation. Three and 5 years after fire all sites were resurveyed to assess vegetation structure, species diversity and vigour, as well as indicators of soil function. Overall, revegetation showed high (>60%) post‐fire survival, but this varied among species depending on regeneration strategy (obligate seeder or resprouter). The native ground cover, mid‐ and overstorey in both types of plantings showed rapid recovery of vegetation structure and cover within 3 years of fire. This recovery was similar to the burnt remnant woodlands. Non‐native (exotic) ground cover initially increased after fire, but was no different in burnt and unburnt sites 5 years after fire. Fire had no effect on species richness, but burnt direct seeding sites had reduced species diversity (Simpson's Diversity Index) while diversity was higher in burnt remnant woodlands. Indices of soil function in all types of vegetation had recovered to levels found in unburnt sites 5 years after fire. These results indicate that even young revegetation (stands <10 years old) showed substantial recovery from disturbance by fire. This suggests that revegetation can provide an important basis for restoring woodland communities in the fire‐prone Australian environment.     

Epigeous macrofungal succession in the first five years following a wildfire in karri (Eucalyptus diversicolor) regrowth forest in Western Australia

Abstract Following a wildfire in 17–25‐year‐old regrowth karri (Eucalyptus diversicolor) forest in the southwest of Western Australia, plots were established in burnt and similarly aged unburnt forest to monitor the fruiting of macrofungi. Thirty‐six plots on 10 sites (five burnt, five unburnt) were surveyed over a 5‐year period. Plots were surveyed every 2 weeks in the macrofungal fruiting season (April to October) and monthly for the remainder of each year. A total of 332 species were recorded. Fire did not impact significantly on mean species richness. However, a distinct mycoflora was recorded on burnt sites, and species composition on burnt sites changed substantially for each year following the fire and after 5 years was still different from that on unburnt sites. Nineteen percent of species recorded were regarded as being present as a direct result of the fire. The study also demonstrated the variable nature of macrofungal sporophore production in the absence of disturbance and the importance of regular sampling. Five distinct succession groups of post‐fire fungi were recognized. The adaptive traits of post‐fire fungi in relation to fire and the management of fire for macrofungal diversity are discussed.     

Effects of a short fire‐return interval on resources and assemblage structure of birds in a tropical savanna

Fire frequency is a key land management issue, particularly in tropical savannas where fire is widely used and fire recurrence times are often short. We used an extended Before‐After‐Control‐Impact design to examine the impacts of repeated wet‐season burning for weed control on bird assemblages in a tropical savanna in north Queensland, Australia. Experimentally replicated fire treatments (unburnt, singularly bunt, twice burnt), in two habitats (riparian and adjacent open woodland), were surveyed over 3 years (1 year before the second burn, 1 year post the second burn, 2 years post the second burn) to examine responses of birds to a rapid recurrence of fire. Following the second burn, species richness and overall bird abundance were lower in the twice‐burnt sites than either the unburnt or singularly burnt sites. Feeding group composition varied across year of survey, but within each year, feeding guilds grouped according to fire treatment. In particular, abundance of frugivores and insectivores was lower in twice‐burnt sites, probably because of the decline of a native shrub that produces fleshy fruits, Carissa ovata. Although broader climatic variability may ultimately determine overall bird assemblages, our results show that a short fire‐return interval will substantially influence bird responses at a local scale. Considering that fire is frequently used as a land management tool, our results emphasize the importance of determining appropriate fire‐free intervals.     

Is the reassembly of an arid spider assemblage following fire deterministic?

Fire is a common disturbance in many ecosystems, including arid Australia. Understanding whether fauna respond in a deterministic manner towards a single end‐point, or to multiple states, is of crucial importance for conservation management. Why different taxa or assemblages display single or multiple end‐points is also important to develop a synthetic theory of succession. To examine the post‐fire changes in assemblages of spiders, we established a chronosequence study in spinifex habitat of central Western Australia. Ground‐active spiders were pitfall‐trapped over nine months in sites representing experimental fires (0 and 0.5 years post‐fire) and wildfires (3, 5, 8 and 20 years post‐fire). There were significant non‐linear changes in species richness, evenness and composition of spiders with increasing post‐fire age. For all three measures, the assemblage appeared highly deterministic, converging towards the long unburnt state. Similarity in richness, evenness and species composition to the 20‐year‐old sites all increased with increasing time since fire (3–8 years). However, experimentally burnt sites did not neatly fit this sequence. We consider two alternative hypotheses to explain this second trajectory: inertia within the system or the rapid migration and recolonization from nearby surrounding unburnt areas. Analyses indicated that half of the 179 species had significant preferences for, or were restricted to, particular post‐fire ages. This suggests that adequate pyrodiversity, both in terms of post‐fire ages and/or scale and intensity of fires, may be important for the conservation of spiders in this habitat. However, owing to the high number of singletons and low indicator values, the significance of this result for conservation management remains equivocal. Despite this, the high degree of determinism provides hope that managers can develop a good predictive understanding of post‐fire successional changes in spider assemblages in arid Australia.     

Long‐term fire exclusion and ant community structure in an Australian tropical savanna: congruence with vegetation succession

Aim To examine the extent to which succession from tropical savanna to rain forest in the long‐term absence of fire is matched by successional changes in ant communities. This is done by describing ant community responses to 23 years of fire exclusion in a northern Australian tropical savanna, with a particular focus on the extent of colonization by specialist rain forest taxa. Location Solar Village, near Darwin in Australia's Northern Territory. Methods Ants were sampled within 12 plots located inside (‘unburnt’– protected from fire for 23 years) and outside (burnt every 1–2 years) Solar Village in ridge and slope habitat dominated by Eucalyptus spp. The litter, ground‐foraging and arboreal faunas were sampled separately, using Berlese funnels, unbaited pitfall traps and baited pitfall traps attached to tree trunks, respectively. Each species was assigned a forest‐association score ranging from 0 (open savanna species) to 3 (specialist forest species) based on their known habitat preferences in the region. Results A total of 85 ant species from 35 genera were recorded, with multivariate analysis demonstrating distinct litter, ground and arboreal communities. Ant communities also varied substantially with topographic position, which interacted strongly with fire exclusion. A total of 72 species were recorded in burnt habitat, compared with only 45 in unburnt, and the number of ant species records was also about twice as high in burnt compared with unburnt habitat. Fire exclusion has resulted in a dramatic increase in forest‐associated taxa (those occurring in forest and denser, but rarely open, savanna), with such species representing 51% of species records in unburnt habitat compared with 19% in burnt. However, only five specialist forest species were recorded, representing < 1% of total ant records. Main conclusions Fire exclusion at Solar Village has markedly increased the prevalence of forest‐associated ant species, but has led to only very minor incursions by specialist rain forest ant taxa. These responses match very closely those of the vegetation.     

The role of Rhytidoponera metallica (Hymenoptera,Formicidae) in facilitating post‐fire seed germination of three ant‐dispersed legume species

The fire avoidance hypothesis proposes that a benefit of seed dispersal by ants (myrmecochory) is to protect seeds from being killed during fire and to facilitate post‐fire germination of seeds that require heat shock to break their physical dormancy. The aim of this study was to quantify the effect of fire and seed burial by a predominant seed‐dispersing ant, Rhytidoponera metallica (subfamily: Ectatomminae) on germination levels of three ant‐dispersed legume species (Pultenaea daphnoides, Acacia myrtifolia and Acacia pycnantha). Experimental burial of seeds within aluminium cans at a site prior to being burnt and at an adjacent unburnt site showed that fire increased germination levels, particularly for seeds buried at 1‐ and 2‐cm deep and that overall, germination levels differed among the three plant species. To quantify seed burial depths and post‐fire germination levels facilitated by R. metallica ants, seeds were fed to colonies prior to fire at the burnt and unburnt sites. Of the seeds buried within nests that were recovered, between 45% and 75% occurred within the upper 6 cm of the soil profile, although unexpectedly, greater percentages of seeds were recovered from the upper 0–2 cm of nests in the unburnt site compared with nests in the burnt site. Germination levels of buried seeds associated with R. metallica nests ranged from 21.2% to 29.5% in the burnt site compared with 3.1–14.8% in the unburnt site. While increased seed germination levels were associated with R. metallica nests following fire, most seeds were buried at depths below those where optimal temperatures for breaking seed dormancy occurred during the fire. We suggest that R. metallica ants may provide fire avoidance benefits to myrmecochorous seeds by burying them at a range of depths within a potential germination zone defined by intra‐ and inter‐fire variation in levels of soil heating.     

Bat activity before and after a severe wildfire in Pilliga forests: Resilience influenced by fire extent and landscape mobility?

Wildfires are becoming increasingly severe and common in many parts of the world, yet their effects on certain taxa remain poorly studied. In November 2006, a major wildfire occurred in the Pilliga forests of north‐west New South Wales, Australia. This fire was severe and extensive, burning more than 120 000 ha. Prior to the fire, we conducted a study in the affected area assessing bat activity in relation to flyway size and riparian zones, allowing us to opportunistically compare before – and – after effects of wildfire on bats in burnt and unburnt areas. We assessed how bat activity and bat composition changed from 1 year pre‐fire to 1 year post‐fire and 4 years post‐fire, accounting for the effects of flyway size. A BACI analysis showed that there was an effect of time (year) on bat activity, with activity markedly reduced in both burnt and unburnt sites in the year post‐ fire, before recovering 4‐years post‐fire to levels that approached pre‐burn activity. However, there was no treatment or interaction effect, indicating fire alone did not affect bat activity at our sites. Activity was 50% lower at supplementary sites more remote (~5 km) from the fire edge. Multi‐dimensional scaling and permanova described a strong effect of year but no evidence of fire or stream size‐mediated effects on species composition. The drop in activity post‐fire coincided with a period of drought that subsequently broke in the year prior to our survey 4 years post‐fire. Some species‐specific responses to the fire were evident and depended on the proximity to unburnt forest. We suggest the potential for landscape re‐assortment, whereby some species may move from the unburnt landscape into the burnt landscape, possibly in response to a resource pulse of insects. A landscape pattern of movement could obscure the detection of direct fire effects on mobile bats. We suggest fire extent, proximity to unburnt vegetation and severity are key considerations when interpreting the response of bats to wildfire.     

More long‐unburnt forest will benefit mammals in Australian sub‐alpine forests and woodlands

The composition of mammalian communities in Australia's Eucalyptus forests and woodlands is known to be affected by fire. However, there are few published studies that compare mammal assemblages in recently burnt and long‐unburnt forests because there are few areas with long‐term fire history data. Understanding the value of long‐unburnt forest is important because it is becoming rare in fire‐prone regions of the world, such as south‐eastern Australia, partly because of the widespread use of prescribed burning. We deployed wildlife cameras for 28 trap‐nights at each of 81 sites that ranged from 0.5 to at least 96 years since the last fire. We recorded a total of 15 native mammal species. At least one mammal species was recorded at 80 of the 81 sites. Significantly more species were detected at long‐unburnt sites (>96 years since fire) than sites 0.5–12 years since the last fire. Species composition varied significantly between sites 0.5–12 years and >96 years since the last fire but did not vary between sites 0.5–2 years and 6–12 years since the last fire. Although there was not one category of time since fire (i.e. 0.5–2 years, 6–12 years and >96 years) in which all 15 native mammal species were recorded, long‐unburnt sites were significantly more important for the occurrence of seven mammal species; intermediate and recently burnt sites were significantly more important for one species. Our results suggested that, while a diversity of fire ages is important for conserving mammalian diversity, long‐unburnt forests and woodlands (which comprised only 8% of our study area) are disproportionately important for mammal conservation. Our results add to a growing body of the literature from south‐eastern Australia, suggesting that remaining long‐unburnt forest should be afforded protection from fire and more forest should be transitioned to long unburnt.     

Fire resilience of ant assemblages in long‐unburnt savanna of northern Australia

Abstract Tropical savannas and rainforests contrast in their flammability and the fire resilience of their associated species. While savanna species generally exhibit high resilience to burning, there is much debate about the fire resilience of forest‐associated species, and the persistence of forest patches in a flammable savanna matrix. Where fire has been excluded, savanna tends on a trajectory towards forest, with an increase in forest‐associated plants and animal species. This study tested the idea that given the high proportion of forest‐associated taxa in long‐unburnt savanna, the fauna of these areas would be expected to exhibit less resilience to fire than the fauna in frequently burnt savannas. The study investigated the immediate and short‐term effects on ant assemblages of re‐introducing fire into long‐unburnt savanna in northern Australia. The ant fauna exhibited high resistance to fires, with no significant short‐term change in mean abundance or species richness; instead, seasonality had a far stronger influence on overall ant activity. Fire caused dramatic declines in dominance of the patchily distributed forest‐associated species Oecophylla smaragdina and Papyrius sp., but had no effect on overall dominance by open savanna species of Iridomyrmex. Dominance by Iridomyrmex pallidus declined, but this was compensated for by increases in I. reburrus, while two other species of Iridomyrmex showed no change. This indicates a high level of functional redundancy among dominant species of Iridomyrmex, which universally dominate open savanna communities, but not of dominant forest‐associated species. Overall, our findings demonstrate a high degree of fire‐resilience of the long‐unburnt savanna ant fauna. Despite the occurrence of forest‐associated species, the high proportion of savanna species persisting in this habitat means that long‐unburnt savanna retains the general response characteristics of frequently burnt savanna.     

Contrasting responses of small mammals to fire and topographic refugia

Unburnt patches within burnt landscapes are expected to provide an important resource for fauna, potentially acting as a refuge from direct effects of fire and allowing animals to persist in burnt landscapes. Nevertheless, there is little information about the way refugia are used by fauna and how populations may be affected by them. Planned burns are often patchy, with unburnt areas generally associated with gully systems providing a good opportunity to study faunal use of refugia. We used a before–after control‐impact design associated with a planned burn in south eastern Australia to investigate how two small mammal species, the bush rat Rattus fuscipes and agile antechinus Antechinus agilis, used unburnt gully systems within a larger burnt area. We tested three alternative hypotheses relating to post‐fire abundance: (i) active refugia – abundance would increase in unburnt patches because of a post‐fire shift of individuals from burnt to unburnt areas; (ii) passive refugia – abundance in unburnt patches would remain similar to pre‐fire levels; and (iii) limited or no refugia – abundance would reduce in unburnt patches related to the change induced by fire in the wider landscape. We found the two species responded differently to the presence of unburnt refugia in the landscape. Relative to controls, fire had little effect on bush rat abundance in gullies, supporting hypothesis 2. In contrast, agile antechinus abundance increased in gullies immediately post‐fire consistent with a shift of individuals from burnt parts of the landscape, supporting hypothesis 1. Differences in site fidelity, habitat use and intraspecific competition between these species are suggested as likely factors influencing responses to refugia. The way unburnt patches function as faunal refugia and the subsequent influence they have on post‐fire population dynamics, will to some extent depend on the life history attributes of individual species.     

Response of vegetation and vertebrate fauna to 23 years of fire exclusion in a tropical Eucalyptus open forest,Northern Territory,Australia

Abstract This opportunistic study compares the vegetation, fuel loads and vertebrate fauna of part of a 120‐ha block of tropical open forest protected from fire for 23 years, and an adjacent block burnt annually over this period. Total fuel loads did not differ significantly between the unburnt and annually burnt sites, but their composition was markedly different, with far less grassy fuel, but far more litter fuel, in the unburnt block. There were major differences between treatments in the composition of trees and shrubs, manifest particularly in the number of stems. There was no overall difference in plant species richness between the two treatments, but richness of woody species was far higher in the unburnt treatment, and of annual and perennial grasses, and perennial herbs in the annually burnt treatment. Change in plant species composition from annually burnt to unburnt treatment was directional, in that there was a far higher representation of rainforest‐associated species (with the percentage of woody stems attributable to ‘rainforest’ species increasing from 24% of all species in the annually burnt treatment to 43% in the unburnt treatment, that of basal area from 9% to 30%, that of species richness from 8% to 17%, and that of cover from 12 to 47%). The vertebrate species composition varied significantly between treatments, but there was relatively little difference in species richness (other than for a slightly richer reptile fauna in the unburnt treatment). Again, there was a tendency for species that were more common in the unburnt treatment to be rainforest‐associated species. The results from this study suggest that there is a sizeable and distinct set of species that are associated with relatively long‐unburnt environments, and hence that are strongly disadvantaged under contemporary fire regimes. We suggest that such species need to be better accommodated by fire management through strategic reductions in the frequency of burning.     

The response of cerambycid beetles (Coleoptera: Cerambycidae) to long‐term fire frequency regimes in subtropical eucalypt forest

Fire has a varied influence on plant and animal species through direct (e.g. fire‐induced mortality) and indirect (e.g. modification of habitat) effects. Our understanding of the influence of fire regime on invertebrates and their response to fire‐induced modifications to habitat is poor. We aimed to determine the response of a beetle family (Coleoptera: Cerambycidae) to varying fire treatments and hypothesised that the abundance of cerambycid beetles is influenced by fire frequency due to modifications in habitat associated with the fire treatments. Arthropods were sampled across 3 months in annually and triennially burnt areas (treatments starting in 1952 and 1973 respectively), an area unburnt since 1946, and a former unburnt treatment, burnt by wildfire in 2006. Eleven different cerambycid taxa were collected using flight intercept panel traps, dominated by three species (Ipomoria tillides, Adrium sp. and Bethelium signiferum) which made up 99% of individuals collected. Over the sampling period the long unburnt treatment had significantly lower species richness than the triennial and wildfire treatments. Cerambycid abundance was significantly higher in the triennially burnt treatment than in all other fire treatments. Ipomoria tillides was more abundant in both frequently burnt treatments, Adrium sp. was more common in triennially burnt areas, whereas B. signiferum, was more common in the wildfire affected treatment. Some, but not all, cerambycid beetles were more common in areas with a more open understorey (i.e. resulting from frequent burning), and lower tree basal area, as this likely influences their ability to fly easily between food sources. Cerambycid abundance was positively related to the volume of coarse woody debris and healthy tree crowns. Cerambycid beetles were clearly influenced by historic fire regime, suggesting that changes in fire regime can potentially have a profound influence on arthropod assemblages, and subsequent influences on ecosystem processes, which are currently poorly understood.     

Regeneration of Juvenile Woody Plants after Fire in a Seasonally Dry Tropical Forest of Southern India

Woody tree species in seasonally dry tropical forests are known to have traits that help them to recover from recurring disturbances such as fire. Two such traits are resprouting and rapid post‐fire growth. We compared survival and growth rates of regenerating small‐sized individuals (juveniles) of woody tree species after dry season fire (February–March) at eight adjacent pairs of burnt and unburnt transects in a seasonally dry tropical forest in southern India. Juveniles were monitored at 3‐mo intervals between August 2009 and August 2010. High juvenile survivorship (>95%) was observed in both burnt and unburnt areas. Growth rates of juveniles, analyzed at the community level as well as for a few species individually (especially fast‐growing ones), were distinctly higher in burnt areas compared to unburnt areas after a fire event, particularly during the pre‐monsoon season immediately after a fire. Rapid growth by juveniles soon after a fire may be due to lowered competition from other vegetative forms such as grasses, possibly aided by the availability of resources stored belowground. Such an adaptation would allow a juvenile bank to be retained in the understory of a dry forest, from where individuals can grow to a possible fire‐tolerant size during favorable conditions.     

Fire severity influences the post-fire habitat structure and abundance of a cool climate lizard

In the spring and summer of 2019–2020, the ‘Black Summer’ bushfires burned more than 97 000 km² of predominantly Eucalyptus dominated forest habitat in eastern Australia. The Black Summer bushfires prompted great concern that many species had been imperilled by the fires. Here, we investigate the effects that fire severity had on the habitat and abundance of a cool climate lizard Eulamprus tympanum that was identified as a species of concern because 37% of its habitat was burnt in the Black Summer bushfires. We quantified habitat structure and the abundance of E. tympanum at sites which were unburnt, burnt at low severity and at high severity 10, 15 and 23 months after the fires. Our classification of fire severity based on scorch height and canopy status corresponded well with the Australian Government Google Earth Engine Burnt Area Map (AUS GEEBAM) fire severity layer. Ten months after the fires, sites burnt at high severity had less canopy cover, more bare ground and less fine fuel than sites burnt at low severity or unburnt sites. The abundance of E. tympanum varied with survey occasion and was greatest during the warmest sampling period and lowest during the coolest sampling period. The abundance of E. tympanum was consistently lower on sites burnt at high severity than sites burnt at low severity or unburnt sites. Our findings show that higher severity fires had a greater effect on E. tympanum than low severity fires. Our results suggest that E. tympanum were likely to have persisted in burnt sites, with populations in low severity and unburnt sites facilitating population recovery in areas burnt at high severity. Our results also suggest that wildfire impacts on E. tympanum populations will increase because the frequency and extent of severe fires are expected to increase due to climate change.     

Rapid Recovery of an Urban Remnant Reptile Community following Summer Wildfire

Reptiles in urban remnants are threatened with extinction by increased fire frequency, habitat fragmentation caused by urban development, and competition and predation from exotic species. Understanding how urban reptiles respond to and recover from such disturbances is key to their conservation. We monitored the recovery of an urban reptile community for five years following a summer wildfire at Kings Park in Perth, Western Australia, using pitfall trapping at five burnt and five unburnt sites. The reptile community recovered rapidly following the fire. Unburnt sites initially had higher species richness and total abundance, but burnt sites rapidly converged, recording a similar total abundance to unburnt areas within two years, and a similar richness within three years. The leaf-litter inhabiting skink Hemiergis quadrilineata was strongly associated with longer unburnt sites and may be responding to the loss of leaf litter following the fire. Six rarely-captured species were also strongly associated with unburnt areas and were rarely or never recorded at burnt sites, whereas two other rarely-captured species were associated with burnt sites. We also found that one lizard species, Ctenotus fallens, had a smaller average body length in burnt sites compared to unburnt sites for four out of the five years of monitoring. Our study indicates that fire management that homogenises large areas of habitat through frequent burning may threaten some species due to their preference for longer unburnt habitat. Careful management of fire may be needed to maximise habitat suitability within the urban landscape.     

Responses of ant communities to experimental fire regimes on rangelands in the Victoria River District of the Northern Territory

Abstract Fire is a significant feature of Australia's savannas. Its use is being encouraged for cattle rangeland management, but there is little knowledge of the ecological effects of prescribed fire regimes on native biodiversity. The responses of ant communities to five experimental fire regimes over 2 years are reported from the Victoria River District in the semi‐arid tropics of northern Australia. The experiment was stratified at two levels: soil type (red and black) and fire treatment (unburnt; burnt twice in successive years in early (May) or late (October) dry season and unburnt thereafter; and burnt twice, 3 years apart, in early or late dry season). Ants were sampled twice in April, corresponding with the end of the 1997 and 1998 wet seasons. Ant species richness was not responsive to fire treatment, but reduced with time since fire on black soil. Total ant abundance also reduced with time since fire on the black soil, with significant different abundances in burnt versus unburnt plots in the 1998 sample. Soil type and sampling time had the greatest influence on ant community composition in multivariate analysis than did fire regime, although there were moderate gradients of time since fire with the black soil plots. The abundance of 19 species were significantly different between fire regimes in anova , 13 on red soil and six on black soil. The abundance of eight species (four each on red and black soil) changed significantly with time since fire, with seven promoted by burning. Ant functional group profiles changed little with fire. Total ant abundance and richness had significant relationships with key pasture species and vegetative variables. The responses of ants largely recapitulated those of plants, birds and reptiles on the same plots. It is envisaged that ants will have an important role to play in the sustainable management of Australia's rangelands aiding the off‐reserve conservation of biodiversity.     

Starting points for small mammal population recovery after wildfire: recolonisation or residual populations?

Wildfire is a major driver of spatio‐temporal variation in terrestrial ecosystems. Large wildfires are predicted to occur more frequently due to climate change. The mechanisms by which post‐fire recovery proceeds are influenced by the abundance of survivors, and their distribution in relation to habitat variability and refugia. Thus, characterising early post‐fire demographic processes is critical to understanding the demographic and community‐level responses of ecosystems to fire. The Black Saturday fires of February 2009 burnt an area of approximately 3500 km² in Victoria, Australia. We quantified the effects of this high severity forest fire on the habitat, abundance, sex ratio and body mass of two small mammal species, the agile antechinus Antechinus agilis and bush rat Rattus fuscipes. We developed a hypothetical framework to distinguish in situ survival and rapid recolonisation as the processes underlying short‐term post‐fire distributions. These hypotheses were based on expected patterns of abundance over increasing distances from unburnt sources, and the estimated recolonisation capabilities of each species and sex. The agile antechinus and bush rat were present in burnt sites at 30% and 12% of the density observed in unburnt sites. In situ survival, and not recolonisation, was the most plausible explanation for our findings. Abundance and body mass data indicated a greater effect of fire on the bush rat than the agile antechinus. The bush rat showed a shift in topographic association, whereby drainage lines acted as post‐fire refugia. Our findings suggest these species do not depend on recolonisation for recovery, and that the bush rat will follow a nucleated recovery, expanding from topographic refugia. Thus, connectivity‐reducing management activities, such as salvage logging and firebreak and road construction, may not affect the early stages of population recovery in remaining stands of burnt forest. Rather, ongoing recovery is likely to be limited by demographic rates and resource availability.     

Fire refugia: The mechanism governing animal survivorship within a highly flammable plant

Identifying factors that influence the survival of individuals during disturbance is critical to understanding patterns of species reassembly within ecological communities. Although most studies of recovery of populations post‐burning acknowledge the potentially important contribution of animals surviving in situ, few have measured the effectiveness of refugia. This paper tests the hypothesis that some plants with tightly packed leaf‐bases provide a refuge for invertebrates during fire (even when the plants themselves burn) by using the highly flammable grass tree (Xanthorrhoeaceae: Xanthorrhoea). Invertebrates were sampled from four unburnt and five experimentally burnt grass trees (Xanthorrhoea preissii Endl.). Also collected were invertebrates fleeing during burning. The dataset comprises 949 specimens, representing 81 species from 18 orders, of which 749 individuals were from unburned plants. Slaters (Isopoda), silverfish (Thysanura), spiders (Araneae) and bugs (Hemiptera) dominated assemblages of the unburnt grass trees. Despite grass trees burning at temperatures of up to 515°C, some invertebrates survived in situ. Species‐specific microhabitat preferences within the plant appeared to influence survivorship. Species collected in the crown of unburned plants were found more often alive on burnt plants than species typically inhabiting the dead skirt of decaying leaves (thatch). We contend that the mechanism causing differential mortality is fire temperature. In the dead skirt, temperatures reached 225.33 ± 66.57°C. In contrast, a region of mild temperature (25.00 ± 3.54°C) persisted throughout burning near the apical meristem (within the crown). We conclude that grass trees are a potential reservoir from which invertebrates might re‐colonize recently burnt areas. However, owing to species‐specific microhabitat preferences and differential mortality across microhabitats, the invertebrate assemblage remaining in situ will be restricted taxonomically compared with the original grass tree fauna. Moreover, different fire regimes might mediate the effectiveness of grass trees as refugia. Finally, we argue that in situ survival of invertebrates within plants with tightly packed leaf‐bases is an unrecognized global phenomenon applicable to a wide array of plant taxa.