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Aim: Climatic extremes and fire affect ecosystems across the globe, yet our understanding of how species are influenced by the interaction of these broadscale ecological drivers is poorly understood. Using a ten‐year dataset, we tested how extreme drought and rainfall interacted with time since fire (TSF) to shape bird species' distributions. Location: Semi‐arid mallee woodlands of south‐eastern Australia. Methods: We quantified the effects of climatic extremes on bird species' occurrence, species richness and incidence at 180 sites across three climatic periods—an El Niño‐associated drought (the "Big Dry"), immediately after La Niña drought‐breaking rainfall ("Big Wet") and three years following the La Niña event ("Post‐Big Wet"). We then compared species' responses with TSF across the three climatic periods using a chronosequence of sites from 1 to 117 years post‐fire. Results: La Niña rainfall had sustained impacts on species' occurrence. Over half of species increased significantly during the Big Wet. Despite three intervening years of below‐average rainfall, three quarters of these species remained comparably high, Post‐Big Wet. By contrast, less than half of threatened and declining species benefited from high rainfall. Responses of species to TSF were found to differ contingent on climatic conditions: almost twice as many species responded to TSF during the Big Wet and almost three times as many Post‐Big Wet, compared with the Big Dry. Across climatic periods, a majority of species showed preference for mid to older post‐fire vegetation. Main conclusions: Variation in responses to TSF is likely due to the effect of climatic variation on resources. We suggest that, at sites of different post‐fire age, interactions between TSF and climate may differentially influence both the availability and longevity of resources. Given climatic extremes are predicted to become increasingly severe with climate change, accounting for their influence on fauna–fire dynamics will require careful management of fire. [ABSTRACT FROM AUTHOR]

Aim Managing fire is critical for the conservation of biodiversity in many ecosystems globally. To manage fire effectively, it is necessary to identify the temporal and spatial scales at which it affects a diverse range of species. This information is challenging to obtain for rare and threatened species for which data often are sparse, and in systems with long fire-return intervals (e.g. >100 years). We tested the effects of a century of fires on the distribution of 12 threatened bird species across a 100,000 km2 region in which 'long-unburnt' vegetation has been identified as important for the diversity of common species. Location Semi-arid mallee woodlands of south-eastern Australia. Methods We developed spatially explicit models to identify the effects of fire history and climatic factors on the distribution of 12 threatened bird species, including two globally endangered species, the Mallee Emu-wren ( Stipiturus mallee) and Black-eared Miner ( Manorina melanotis). Results Fire was a driver of distribution for all species. Four species were common in younger vegetation (<20 years post-fire) and 11 were most common in mid (20-60 years post-fire) to older (>60 years post-fire) vegetation. Species' distributions were further restricted to areas associated with particular vegetation types and climatic conditions. Main conclusions Comprehensive investigation of the response to fire by a range of threatened species highlights the importance of what is now recognized as mid-successional mallee vegetation (20-60 years post-fire), and that species' preferences for previously identified 'long-unburnt' vegetation extend to ≥60 years post-fire. Fire management conducted with incomplete knowledge, or which is focussed on introducing prescribed burns or suppressing fires for early/late-successional species alone, is unlikely to maximize biodiversity. Effective fire management for biodiversity requires the promotion of ecological processes that result in key successional stages at particular locations in the landscape. [ABSTRACT FROM AUTHOR]

Aim Strongly interacting species have disproportionately large ecological effects relative to their abundances or biomass. We previously developed two conceptual models that described how one such strong interactor, the Australian bird the noisy miner Manorina melanocephala: (1) establishes resident high-density and hyperaggressive colonies and (2) in doing so, affects other biota and ecosystem processes. Here, we evaluate parts of those models relating to noisy miner habitat preferences and effects on bird assemblages using data from across the geographical range of the miner. Location Eastern Australia. Methods Avian-assemblage data were compiled for 2128 survey transects (distributed over > 1.39 106 km²) and were linked to variables reflecting productivity, local habitat structure and landscape context. Predictors were chosen based on the models, although detailed data for some variables were unavailable at such large scales. We used hierarchical Bayesian models that included observation models to account for different survey effort coupled with potentially nonlinear, spatially-explicit process models. Conclusions Noisy miner densities increased with proximity to forest edges (higher densities on forest edges and open sites), in low rainfall areas, and in vegetation dominated by trees with blade-shaped rather than needle-shaped leaves. The presence of noisy miners at even relatively small densities (> 0.6 individuals ha1) depressed both species richness and the abundances of smaller (< 63 g) bird species, by 50% on average. There were positive associations between densities of noisy miners and the abundance and richness of larger-bodied (> 63 g) bird species. In areas with higher mean rainfall, the associations between noisy miners and small- and large-bird species were more negative and less positive, respectively. [ABSTRACT FROM AUTHOR]

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 km2) 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. [ABSTRACT FROM AUTHOR]

Aim Reports of profound changes in species assemblages brought about by the influence of strongly interacting species are increasingly common. Where these strong interactors are sensitive to anthropogenic habitat changes, relatively small alterations in the environment can result in large and pervasive shifts in assemblages. We review the evidence for widespread assemblage-level phase shifts across eastern Australia, triggered partly by anthropogenic habitat alteration and mediated by a native, despotic bird: the noisy miner Manorina melanocephala. Location Eastern Australia. Methods Based on the literature, we developed conceptual models of factors affecting site occupancy by, and ecosystem-level effects of, the noisy miner. We also analysed recent trends in the reporting rate of the noisy miner across its range. Results Individuals of this species cooperate to aggressively exclude almost all smaller bird species from the areas they occupy. The noisy miner is advantaged by habitat fragmentation and structural simplification-habitat changes that facilitate detection and interception of potential competitors by miners. We report that the species is increasingly prevalent, particularly close to forest and woodland edges. Such edges have mainly been created by human land use. The evidence we reviewed showed: (1) strong causal links between the noisy miner and depressed richness and abundance of smaller birds, particularly nectarivores and insectivores; (2) moderate evidence of a positive association with larger bird species; (3) reduced tree condition stemming from impaired control of insect herbivore populations by smaller insectivores; and (4) a plausible negative effect on plant reproduction through reduced tree condition, altered pollination services and altered seed dispersal. Main conclusions This is the first synthesis to document the causes and likely ecological consequences of increasingly prevalent phase shifts catalysed by a despotic species on ecosystems at very large spatial scales (> 1 million km2). Native species affected by human activities can become agents that induce ecological dysfunction. [ABSTRACT FROM AUTHOR]

Aim A common strategy for conserving biodiversity in fire-prone environments is to maintain a diversity of post-fire age classes at the landscape scale, under the assumption that 'pyrodiversity begets biodiversity'. Another strategy is to maintain extensive areas of a particular seral state regarded as vital for the persistence of threatened species, under the assumption that this will also cater for the habitat needs of other species. We investigated the likely effects of these strategies on bird assemblages in tree mallee vegetation, characterized by multi-stemmed Eucalyptus species, where both strategies are currently employed. Location The semi-arid Murray Mallee region of south-eastern Australia. Methods We systematically surveyed birds in 26 landscapes (each 4-km diameter), selected to represent gradients in the diversity of fire age classes and the proportion of older vegetation (> 35 years since fire). Additional variables were measured to represent underlying vegetation- or fire-mediated properties of the landscape, as well as its biogeographic context. We used an information-theoretic approach to investigate the relationships between these predictor variables and the species richness of birds (total species, threatened species and rare species). Results Species richness of birds was not strongly associated with fire-mediated heterogeneity. Species richness was associated with increasing amounts of older vegetation in landscapes, but not with the proportion of recently burned vegetation in landscapes. Main conclusions The preference of many mallee birds for older vegetation highlights the risk of a blanket application of the 'pyrodiversity begets biodiversity' paradigm. If application of this paradigm involved converting large areas from long unburned to recently burned vegetation to increase fire-mediated heterogeneity in tree mallee landscapes, our findings suggest that this could threaten birds. This research highlights the value of adopting a landscape-scale perspective when evaluating the utility of fire-management strategies intended to benefit biodiversity. [ABSTRACT FROM AUTHOR]

Fire affects the structure and dynamics of ecosystems world-wide, over long time periods (decades and centuries) and at large spatial scales (landscapes and regions). A pressing challenge for ecologists is to develop models that explain and predict faunal responses to fire at broad temporal and spatial scales. We used a 105-year post-fire chronosequence to investigate small mammal responses to fire across an extensive area of 'tree mallee' (i.e. vegetation characterized by small multi-stemmed eucalypts). The Murray Mallee region (104,000 km²) of semi-arid Australia. First, we surveyed small mammals at 260 sites and explored the fire responses of four species using nonlinear regression models. Second, we assessed the predictive accuracy of models using cross-validation and by testing with independent data. Third, we examined our results in relation to an influential model of animal succession, the habitat accommodation model. Two of four study species showed a clear response to fire history. The distribution of the Mallee Ningaui Ningaui yvonneae, a carnivorous marsupial, was strongly associated with mature vegetation characterized by its cover of hummock grass. The occurrence of breeding females was predicted to increase up to 40-105 years post-fire, highlighting the extensive time periods over which small mammal populations may be affected by fire. Evaluation of models for N. yvonneae demonstrated that accurate predictions of species occurrence can be made from fire history and vegetation data, across large geographical areas. The introduced House Mouse Mus domesticus was the only species positively associated with recently burnt vegetation. Understanding the impact of fire over long time periods will benefit ecological and conservation management. In this example, tracts of long-unburnt mallee vegetation were identified as important habitat for a fire-sensitive native mammal. Small mammal responses to fire can be predicted accurately at broad spatial scales; however, a conceptual model of post-fire change in community structure developed in temperate Australia is not, on its own, sufficient for small mammals in semi-arid systems. [ABSTRACT FROM AUTHOR]