Article

Ant diversity in relation to time since fire in a mallee landscape of South‐Eastern Australia

Authors:
  • Museums Victoria
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Fire is a dominant process shaping the Australian landscape and in many regions the frequency and severity of wildfires are predicted to increase under climate change. The primary impact of fire on fauna is typically indirect through habitat change. In particular, in mesic forests different animal species are favoured at different times since fire as habitat complexity increases with vegetation recovery. However, this will not necessarily be the case in habitats with low complexity such as many of those occurring in arid and semi‐arid regions. Here, we investigate the relationship between fire history and ant diversity and composition in semi‐arid mallee of south‐eastern Australia. We surveyed ants at 11 sites in the Little Desert National Park and nearby private land that last burnt 0.5, 6 or 40 years ago. We found no relationship between time since fire and either ant diversity or composition, and this can be explained by a lack of relationship between time since fire and vegetation cover. Our findings contrast with those for mallee bird species, which show clear successional patterns following fire, but are likely to be typical of ground‐foraging fauna that lack specialized habitat requirements.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Studies on fire's impacts have traditionally focused on plants but during the last decade there is increasing research exploring fire's impact on animals (Engstrom 2010;Beale et al., 2018;Nimmo et al., 2018Nimmo et al., , 2021Pausas and Parr 2018;Jolly et al., 2022) and especially on insects (New 2014). Regarding ants, most studies of fire effects analysed taxonomic richness and abundance (Farji-Brener et al., 2002;Parr et al., 2004;Moretti et al., 2004;Arnan et al., 2006;Sackmann and Farji-Brener 2006;Kwon 2015;Anjos et al., 2015Anjos et al., , 2017Vasconcelos et al., 2017;Adams et al., 2018;Rosa et al., 2021;Bonoan and McCarthy 2022;Staff et al., 2023), sometimes combined with functional diversity Bishop et al., 2021;Vidal-Cordero et al., 2022, 2023, or focusing on some after-fire specific ecological responses such as ant-seed dispersal Beaumont et al., 2013Beaumont et al., , 2018, female production (Caut et al., 2014), diet shifts (Lázaro-González et al., 2013), or cavity use by arboreal ants (Arruda et al., 2020). Finally, recent behavioural studies show how fire can have an effect on ant behaviour, specifically relationships of dominance between species (Sensenig et al., 2017;Tavella and Cagnolo, 2018). ...
Thesis
Full-text available
Forest fires are one of the most frequent disturbances in Mediterranean environments. They greatly alter forest ecosystems, modifying the structure and composition of plant communities which consequently affects the structure and composition of the animal communities that inhabit them. The general objective of this Doctoral Thesis is to investigate the short-, medium- and long-term response three groups of arthropods have to fire in coniferous systems in Mediterranean environments of the Iberian Peninsula. We studied the structure and composition of the communities of ants, bees and spiders affected by fire from a taxonomic and functional point of view. We also measured how fire affects the hierarchy of dominance in ant communities. For this purpose, field sampling was carried out using pitfall traps, Moericke traps and baits in pine forests of the Iberian Peninsula affected by forest fires that occurred varying periods of time. Fire had a more pronounced effect on the communities of ants than in did on those of bees and spiders. The taxonomic response of ants (abundance, richness and diversity) varied highly. These variables decreased in the short-term in one case, recovered in the short-term in another case, and they even increased, independently of the time elapsed after the fire. At the functional level, the ant communities in burned areas are predominantly composed of thermophilic and subordinate species, and also of dominant species in more open habitats. In unburned areas, however, the species tend to be less thermophilic and are associated with more developed vegetation, especially the tree layer and tall shrubs. Therefore, fire may act as a niche filtering mechanism, with a long-term effect on some functional traits and a short-term effect on other ones. In conclusion, fire alters arthropod communities at the taxonomic and functional level, especially in ants. Taxonomic alterations are variable and depend more on the local scale (the recovery of the vegetation and the types of ant community present before the fire), while functional alterations are longer-term and more predictable.
Article
Full-text available
Planned burning generates different types of pyrodiversity, however, experimental tests of how alternative spatial patterns of burning influence animal communities remain rare. Field tests are needed to understand the mechanisms through which spatial variation in planned fire affects fauna, and how fire can be applied to benefit biodiversity. We tested five hypotheses of how fire‐driven variation in habitat composition and configuration affects fauna at fine scales. Small mammal, reptile and invasive predator activity was monitored at 12 burnt and eight unburnt sites through the year following a large, planned burn in semi‐arid ‘mallee’ woodlands of southern Australia. We explored measures of burnt or unburnt habitat (‘habitat status’); amount of unburnt vegetation (‘habitat amount’); interspersion of burnt and unburnt patches (‘habitat complementation’); distance to external or internal unburnt vegetation (‘habitat connectivity’); and unburnt patch size and local vegetation cover (‘habitat refuge’). Generalized linear models were used to test the influence of each variable on capture rates of three small mammal and 11 reptile species; activity of the introduced red fox (Vulpes vulpes); and species richness of native animals. We found strong support for the habitat status hypothesis and moderate support for four hypotheses relating to spatial patterns of fire. Reptile assemblages varied between burnt and unburnt sites, and relationships were identified between abundance of one or more reptile species and each measure of spatial variation. Reptile species richness was higher at unburnt sites and at sites with more unburnt vegetation in the surrounding area. Sites that were less connected to unburnt vegetation had fewer reptile species. Mammals did not have clear relationships with fine‐scale fire patterns. Synthesis and applications. Application of planned fire to promote biodiversity is globally important. We show that retaining unburnt areas and well‐connected habitat refuges is important for reptile diversity. We also found that several species of small mammals and reptiles appear resilient to the fine‐scale patterns of planned fire experienced in this study, despite activity of introduced predators. The diversity of animals can remain relatively high in areas subject to planned fire, provided that internal and external habitat refuges are retained.
Article
Full-text available
Earth's rapidly warming climate is propelling us towards an increasingly fire-prone future. Currently, knowledge of the extent and characteristics of animal mortality rates during fire remains rudimentary, hindering our ability to predict how animal populations may be impacted in the future. To address this knowledge gap, we conducted a global systematic review of the direct effects of fire on animal mortality rates, based on studies that unequivocally determined the fate of animals during fire. From 31 studies spanning 1984–2020, we extracted data on the direct impacts of fire on the mortality of 31 species from 23 families. From these studies, there were 43 instances where direct effects were measured by reporting animal survival from pre- to post-fire. Most studies were conducted in North America (52%) and Oceania (42%), focused largely on mammals (53%) and reptiles (30%), and reported mostly on animal survival in planned (82%) and/or low severity (70%) fires. We found no studies from Asia, Europe or South America. Although there were insufficient data to conduct a formal meta-analysis, we tested the effect of fire type, fire severity, fire regime, animal body mass, ecological attributes and class on survival. Only fire severity affected animal mortality, with a higher proportion of animals being killed by high than low severity fires. Recent catastrophic fires across the globe have drawn attention to the plight of animals exposed to wildfire. Yet, our systematic review suggests that a relatively low proportion of animals (mean predicted mortality [95% CI] = 3% [1%–9%]) are killed during fire. However, our review also underscores how little we currently know about the direct effects of fire on animal mortality, and highlights the critical need to understand the effects of high severity fire on animal populations.
Article
Full-text available
The 2019/20 Black Summer bushfire disaster in southeast Australia was unprecedented: the extensive area of forest burnt, the radiative power of the fires, and the extraordinary number of fires that developed into extreme pyroconvective events were all unmatched in the historical record. Australia’s hottest and driest year on record, 2019, was characterised by exceptionally dry fuel loads that primed the landscape to burn when exposed to dangerous fire weather and ignition. The combination of climate variability and long-term climate trends generated the climate extremes experienced in 2019, and the compounding effects of two or more modes of climate variability in their fire-promoting phases (as occurred in 2019) has historically increased the chances of large forest fires occurring in southeast Australia. Palaeoclimate evidence also demonstrates that fire-promoting phases of tropical Pacific and Indian ocean variability are now unusually frequent compared with natural variability in pre-industrial times. Indicators of forest fire danger in southeast Australia have already emerged outside of the range of historical experience, suggesting that projections made more than a decade ago that increases in climate-driven fire risk would be detectable by 2020, have indeed eventuated. The multiple climate change contributors to fire risk in southeast Australia, as well as the observed non-linear escalation of fire extent and intensity, raise the likelihood that fire events may continue to rapidly intensify in the future. Improving local and national adaptation measures while also pursuing ambitious global climate change mitigation efforts would provide the best strategy for limiting further increases in fire risk in southeast Australia.
Article
Full-text available
Aim Fire is particularly frequent, complex and contentious in the vast tropical savannas of northern Australia, where declines in many threatened species are associated with fire, and substantial areas are under fire management for greenhouse gas abatement. Controlled field experiments are crucial for understanding biodiversity responses, and here I present key insights into faunal responses to fire that have been revealed by them, along with their lessons for fire management. Location Australian monsoonal tropics. Methods Results are synthesized from six replicated fire experiments that have been conducted in Australian savannas and include multispecies assessments of fauna. The synthesis also draws on other fire studies and is presented in the form of five key insights into faunal responses. Results The key insights are as follows: (a) most faunal groups are extremely resilient to fire, with highly contrasting fire regimes often having little or no detectable impact on species abundances, at least in the medium term; (b) the most important effects of fire are typically indirect through habitat modification, even when there is substantial direct mortality; (c) fire intensity is not as important a factor as is widely thought; rather, fire frequency is particularly important; (d) there will always be winners and losers with any fire; and (e) fire is required for the maintenance of diversity. Main conclusions These insights have important implications for conservation management in Australian savannas: management needs to focus on fire‐induced changes to habitat suitability, and to consider faunal outcomes at the landscape scale; a combination of frequently (every 2–3 years) and less frequently (every ≥5 years) burned habitat may adequately conserve the great majority of animal species without a need for complex fire mosaics; special management attention is required for frequent‐fire losers because of an extremely low representation of longer‐unburnt habitat; and fire needs to be actively managed to promote diversity, not excluded. The insights are widely applicable to tropical grassy ecosystems more generally, and some appear to be universal to fire‐prone biomes.
Article
Full-text available
Ecological disturbance is fundamental to the dynamics of biological communities, yet a conceptual framework for understanding the responses of faunal communities to disturbance remains elusive. Here, I propose five principles for understanding the disturbance dynamics of ants—a globally dominant faunal group that is widely used as bioindicators in land management, which appear to have wide applicability to other taxa. These principles are as follows: (1) The most important effects of habitat disturbance on ants are typically indirect, through its effects on habitat structure, microclimate, resource availability and competitive interactions; (2) habitat openness is a key driver of variation in ant communities; (3) ant species responses to disturbance are to a large degree determined by their responses to habitat openness; (4) the same disturbance will have different effects on ants in different habitats, because of different impacts on habitat openness; and (5) ant community responses to the same disturbance will vary according to ant functional composition and biogeographical history in relation to habitat openness. I illustrate these principles using results primarily from studies of ant responses to fire, a dominant agent of disturbance globally, to provide a common disturbance currency for comparative analysis. I argue that many of the principles also apply to other faunal groups and so can be considered as general ecological “laws.” As is the case for ants, many impacts of habitat disturbance on other faunal groups are fundamentally related to habitat openness, the effects of disturbance on it and the functional composition of species in relation to it.
Article
Full-text available
We conducted a meta-analysis of the effects of fire on the abundance and alpha diversity of ants based upon data published over the past 70 years. Overall, fire reduced ant diversity by 18 %, but had no effect on ant abundance. However, there was significant variation in the effect of fire on ant diversity amongst different vegetation types. Fire significantly decreased ant diversity in forests—especially in tropical forests—whereas in deserts, grasslands, and savannas it did not. Similarly, fire had a strong negative mean effect on ant diversity in sites where it is uncommon, but did not significantly affect diversity where it is a recurrent phenomenon. There is evidence that, in forests, wildfires have a stronger negative effect on ant diversity than does prescribed burning. In addition, we found marginally significant differences in the effect of fire on the abundance and diversity of forest ants among studies that sampled ants at different times post-fire, or that sampled ants from different soil strata. In contrast, fire did not significantly affect the abundance or diversity of savanna ants, and this was true even after we took into account the geographic location of the study, the ant community sampled, the time since fire, and the fire regime. Overall, the results of our study indicate that habitat type is an important predictor of ant community responses to fire. However, even within a given habitat, reported effects were quite variable among the studies reviewed, evidencing the idiosyncratic nature of fire effects on ants.
Article
Full-text available
Termites play an important ecological role in many ecosystems, particularly in nutrient-poor arid and semi-arid environments. We examined the distribution and occurrence of termites in the fire-prone, semi-arid mallee region of south-eastern Australia. In addition to periodic large wildfires, land managers use fire as a tool to achieve both asset protection and ecological outcomes in this region. Twelve taxa of termites were detected by using systematic searches and grids of cellulose baits at 560 sites, clustered in 28 landscapes selected to represent different fire mosaic patterns. There was no evidence of a significant relationship between the occurrence of termite species and time-since-fire at the site scale. Rather, the occurrence of species was related to habitat features such as the density of mallee trees and large logs (>10 cm diameter). Species richness was greater in chenopod mallee vegetation on heavier soils in swales, rather than Triodia mallee vegetation of the sandy dune slopes. At the landscape scale, there was little evidence that the frequency of occurrence of termite species was related to fire, and no evidence that habitat heterogeneity generated by fire influenced termite species richness. The most influential factor at the landscape scale was the environmental gradient represented by average annual rainfall. Although termites may be associated with flammable habitat components (e.g. dead wood), they appear to be buffered from the effects of fire by behavioural traits, including nesting underground, and the continued availability of dead wood after fire. There is no evidence to support the hypothesis that a fine-scale, diverse mosaic of post-fire age-classes will enhance the diversity of termites. Rather, termites appear to be resistant to the effects of fire at multiple spatial scales.
Article
Full-text available
Fractional green canopy cover (FGCC) is a key diagnostic variable that can be used to estimate canopy development, light interception, and evapotranspiration partitioning. Available image analysis tools for quantifying FGCC are time-consuming or expensive and cannot analyze video. Our objective was to develop a simple, accurate, and rapid tool to analyze FGCC from images and videos. This tool, called Canopeo, was developed using Matlab and is based on color ratios of red to green (R/G) and blue to green (B/G) and an excess green index (2G– R–B). The output from this tool was compared to that from two soft ware packages widely used to analyze FGCC, Sample Point, and SigmaScan Pro. Canopeo’s image processing speed was 20 to 130 times faster than SigmaScan and 75 to 2500 times faster than SamplePoint. Canopeo correctly classified 90% of pixels when compared to SamplePoint. Root mean squared difference (RMSD) values for Canopeo FGCC vs. FGCC determined by SamplePoint and SigmaScan ranged from 0.04 to 0.12, with an average RMSD of 0.073 across several sets of images of corn (Zea mays L.), forage sorghum [Sorghum bicolor (L.) Moench], bermuda grass [Cynodon dactylon (L.) Pers.], and switchgrass (Panicum virgatum L.). Analysis of video recordings of transects over crop canopies proved to be useful to minimize sampling error and to quantify FGCC spatial variability. This analysis was simple and rapid with Canopeo but not possible with SamplePoint or SigmaScan. The Canopeo app for Matlab and for iOS and Android mobile devices can be downloaded at www.canopeoapp.com. © 2015 by the American Society of Agronomy 5585 Guilford Road, Madison, WI 53711 USA All rights reserved.
Article
Full-text available
Maximum likelihood or restricted maximum likelihood (REML) estimates of the parameters in linear mixed-effects models can be determined using the lmer function in the lme4 package for R. As for most model-fitting functions in R, the model is described in an lmer call by a formula, in this case including both fixed- and random-effects terms. The formula and data together determine a numerical representation of the model from which the profiled deviance or the profiled REML criterion can be evaluated as a function of some of the model parameters. The appropriate criterion is optimized, using one of the constrained optimization functions in R, to provide the parameter estimates. We describe the structure of the model, the steps in evaluating the profiled deviance or REML criterion, and the structure of classes or types that represents such a model. Sufficient detail is included to allow specialization of these structures by users who wish to write functions to fit specialized linear mixed models, such as models incorporating pedigrees or smoothing splines, that are not easily expressible in the formula language used by lmer.
Article
Full-text available
Ants are important for the maintenance and functioning of many ecosystems and provide a variety of ecosystem services and disservices. This review summarizes information on ecosystem services provided by ants in a framework modeled after the Millennium Ecosystem Assessment. In this framework, ecosystem services are divided into provisioning, regulating, cultural, and supporting services, and we show that ants provide services in each of these categories. We also present a review of some of the major disservices mediated by ants (i.e., the roles of ants that have negative consequences on human and environmental health, and societal well-being). Our review does not exhaustively review any single ecosystem service or disservice, but rather pieces together the many ways in which ants are influential in our changing planet and society. We conclude by describing future areas of research that will help better understand the impact of ants on ecosystems and society.
Article
Full-text available
Humans and their ancestors are unique in being a fire-making species, but ‘natural’ (i.e. independent of humans) fires have an ancient, geological history on Earth. Natural fires have influenced biological evolution and global biogeochemical cycles, making fire integral to the functioning of some biomes. Globally, debate rages about the impact on ecosystems of prehistoric human-set fires, with views ranging from catastrophic to negligible. Understanding of the diversity of human fire regimes on Earth in the past, present and future remains rudimentary. It remains uncertain how humans have caused a departure from ‘natural’ background levels that vary with climate change. Available evidence shows that modern humans can increase or decrease background levels of natural fire activity by clearing forests, promoting grazing, dispersing plants, altering ignition patterns and actively suppressing fires, thereby causing substantial ecosystem changes and loss of biodiversity. Some of these contemporary fire regimes cause substantial economic disruptions owing to the destruction of infrastructure, degradation of ecosystem services, loss of life, and smoke-related health effects. These episodic disasters help frame negative public attitudes towards landscape fires, despite the need for burning to sustain some ecosystems. Greenhouse gas-induced warming and changes in the hydrological cycle may increase the occurrence of large, severe fires, with potentially significant feedbacks to the Earth system. Improved understanding of human fire regimes demands: (1) better data on past and current human influences on fire regimes to enable global comparative analyses, (2) a greater understanding of different cultural traditions of landscape burning and their positive and negative social, economic and ecological effects, and (3) more realistic representations of anthropogenic fire in global vegetation and climate change models. We provide an historical framework to promote understanding of the development and diversification of fire regimes, covering the pre-human period, human domestication of fire, and the subsequent transition from subsistence agriculture to industrial economies. All of these phases still occur on Earth, providing opportunities for comparative research.
Article
Full-text available
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.
Article
Knowledge on the distribution and abundance of organisms is fundamental to understanding their roles within ecosystems and their ecological importance for other taxa. Such knowledge is currently lacking for insects, which have long been regarded as the “little things that run the world”. Even for ubiquitous insects, such as ants, which are of tremendous ecological significance, there is currently neither a reliable estimate of their total number on Earth nor of their abundance in particular biomes or habitats. We compile data on ground-dwelling and arboreal ants to obtain an empirical estimate of global ant abundance. Our analysis is based on 489 studies, spanning all continents, major biomes, and habitats. We conservatively estimate total abundance of ground-dwelling ants at over 3 × 10 ¹⁵ and estimate the number of all ants on Earth to be almost 20 × 10 ¹⁵ individuals. The latter corresponds to a biomass of ∼12 megatons of dry carbon. This exceeds the combined biomass of wild birds and mammals and is equivalent to ∼20% of human biomass. Abundances of ground-dwelling ants are strongly concentrated in tropical and subtropical regions but vary substantially across habitats. The density of leaf-litter ants is highest in forests, while the numbers of actively ground-foraging ants are highest in arid regions. This study highlights the central role ants play in terrestrial ecosystems but also major ecological and geographic gaps in our current knowledge. Our results provide a crucial baseline for exploring environmental drivers of ant-abundance patterns and for tracking the responses of insects to environmental change.
Book
Ants are one of the most important faunal groups in Australia and are widely used as bioindicators in land monitoring and assessment programs. The Ants of Northern Australia will help in the identification of the 1500 or more ant species occurring in monsoonal Australia, an area which encompasses most of the northern third of the continent. Until now, no book has described the northern Australian ant fauna below genus level. Such a treatment is required to support and promote the numerous ecological studies involving ants, especially in the context of their use as bioindicators. The Ants of Northern Australia features original analyses of genera at the species-group level, and so has relevance throughout Australia. It treats all major species that have been described, as well as numerous others that remain undescribed.
Article
A species-rich small-mammal community on 7 ha of diverse coastal heath in Myall Lakes National Park, New South Wales, Australia, was studied for 7 mo before the area burned in a wildfire (August 1974) and has subsequently been monitored for 5 yr since the fire. Species regularly trapped were the dasyurids Antechinus stuartii and Sminthopsis murina, the peramelid Isoodon macrourus, and the native murids Pseudomys novaehollandiae and P. gradcilicaudatus, together with the introduced Mus musculus. Pseudomys species, M. musculus, and S. murina reached greater abundance on early seral stages, while the abundance there of both Rattus fuscipes and R. lutreolus was much reduced. Species reach peak abundance in an orderly replacement sequence exhibiting a mammalian secondary succession. A habitat accommodation model is proposed with species entering the succession and reaching peak abundance as externally controlled changes in the vegetation fulfil the habitat requirements of each species. Species leave the succession or are greatly reduced in abundance when these local physical conditions move out of the optimal range for the species. This study shows that a major perturbation of a small-mammal community can produce a variety of responses among species, suggesting that regeneration time may represent a resource axis subdivided by community members in this secondary succession. The rapid recovery illustrated by the total number of individuals, as a measure of community response, support the suggestion that fire and fire frequency have been major factors in producing a fire-adapted, species-rich small-mammal community on this heathland.
Article
Aim A common assumption in fire ecology and management is that landscapes with a greater diversity of fire‐ages will support a greater diversity of animal species (i.e. ‘pyrodiversity begets biodiversity’). This assumption is based on the idea that landscapes with a more diverse fire history provide a greater array of post‐fire habitats, leading to a greater number of species within the landscape. We assessed the hypothesis that pyrodiversity begets biodiversity by enhancing community differentiation (β diversity), resulting in increased landscape‐scale richness (γ‐diversity). We used reptiles as a case‐study. Location The Mallee region of south‐eastern Australia. Methods We used a study design in which ‘whole’ fire mosaics (12.6 km ² ) were the unit of replication. Study landscapes ( n = 28) were selected to represent a gradient in the diversity and extent of fire‐age classes. We surveyed reptiles by using pitfall traps at 10 sites within each landscape (280 sites in total). Reptile data were used to characterize reptile assemblages at the landscape‐scale in three ways: alpha (average within‐site diversity), beta (between‐site diversity) and gamma diversity (total diversity). Results The diversity of fire‐age classes had little influence on the alpha, beta or gamma diversity of reptile assemblages. The properties of fire mosaics that most influenced assemblages were the extent of structurally important fire‐age classes. The extent of long‐unburned vegetation increased beta diversity but reduced alpha diversity of the total reptile assemblage, essentially cancelling each other out at the landscape scale. Main conclusions This study highlights the importance of considering multiple measures of diversity when exploring the influence of landscape properties on biodiversity, as ‘null’ results at the landscape scale (gamma diversity) can result from contrasting patterns in alpha and beta diversity. Using fire to create habitat mosaics, at the scale of this study, is unlikely to enhance the status of reptiles in the region.
Article
The immediate effects of a high intensity wildfire on the ant communities of a heath and a mallee site in semi-arid north-western Victoria are reported. Following fire the number of species trapped on the ground doubled (to ca. 80 each site), total ant abundance decreased by half (due to the demise of previously dominant species), surface activity of reproductive castes increased, and dramatic changes in species relative abundance (including shifts toward greater equitability) occurred. These changes are interpreted in terms of fire-induced simplification of the habitat and release from competition with dominant species. The results appear to illustrate the importance of interspecific competition in structuring foraging activity in mallee ant communities. Observations are also reported on seed-harvesting by ants, including changes in harvester ant abundance, germination from within-nest seed storage, and the first record of Heteroponera removing seeds.
Article
Knowing how species respond to fire regimes is essential for ecologically sustainable management. This axiom raises two important questions: (1) what knowledge is the most important to develop and (2) to what extent can current research methods deliver that knowledge? We identify three areas of required knowledge: (i) a mechanistic understanding of species’ responses to fire regimes; (ii) knowledge of how the spatial and temporal arrangement of fires influences the biota; and (iii) an understanding of interactions of fire regimes with other processes. We review the capacity of empirical research to address these knowledge gaps, and reveal many limitations. Manipulative experiments are limited by the number and scope of treatments that can be applied, natural experiments are limited by treatment availability and confounding factors, and longitudinal studies are difficult to maintain, particularly due to unplanned disturbance events. Simulation modelling is limited by the quality of the underlying empirical data and by uncertainty in how well model structure represents reality. Due to the constraints on large-scale, long-term research, the potential for management experiments to inform adaptive management is limited. Rather than simply recommending adaptive management, we define a research agenda to maximise the rate of learning in this difficult field. This includes measuring responses at a species level, building capacity to implement natural experiments, undertaking simulation modelling, and judicious application of experimental approaches. Developing ecologically sustainable fire management practices will require sustained research effort and a sophisticated research agenda based on carefully targeting appropriate methods to address critical management questions.
Article
he sight of land managers poring over ant checklists is a regular occurrence in Australia, where ant monitoring has been successfully applied to a wide range of land-use situations. The robustness of ants as ecological indicators has been consistently demonstrated, and is supported by an extensive understanding of their community dynamics in relation to disturbance. Despite the widespread recognition of the value of terrestrial invertebrates as bioindicators, the use of ants represents one of the few examples where invertebrates are widely adopted in land management as indicator organisms, as opposed to being consigned to the “too hard” basket. The use of invertebrates as bioindicators in land management will always require specialist expertise and a substantial investment in resources. However, research in Australia shows that invertebrate monitoring does not require comprehensive surveys, and that it is possible to simplify sampling and processing without compromising indicator performance.