Weather, Not Climate, Defines Distributions of Vagile Bird Species

Background\ud \ud Accurate predictions of species distributions are essential for climate change impact assessments. However the standard practice of using long-term climate averages to train species distribution models might mute important temporal patterns of species distribution. The benefit of using temporally explicit weather and distribution data has not been assessed. 1We hypothesized that short-term weather associated with the time a species was recorded should be superior to long-term climate measures for predicting distributions of mobile species.\ud \ud Methodology\ud \ud We tested our hypothesis by generating distribution models for 157 bird species found in Australian tropical savannas (ATS) using modelling algorithm Maxent. The variable weather of the ATS supports a bird assemblage with variable movement patterns and a high incidence of nomadism. We developed “weather” models by relating climatic variables (mean temperature, rainfall, rainfall seasonality and temperature seasonality) from the three month, six month and one year period preceding each bird record over a 58 year period (1950–2008). These weather models were compared against models built using long-term (30 year) averages of the same climatic variables.\ud \ud Conclusions\ud \ud Weather models consistently achieved higher model scores than climate models, particularly for wide-ranging, nomadic and desert species. Climate models predicted larger range areas for species, whereas weather models quantified fluctuations in habitat suitability across months, seasons and years. Models based on long-term climate averages over-estimate availability of suitable habitat and species' climatic tolerances, masking species potential vulnerability to climate change. Our results demonstrate that dynamic approaches to distribution modelling, such as incorporating organism-appropriate temporal scales, improves understanding of species distributions

Burdekin catchment study – a desktop study of environmental issues associated with dam and irrigation area development

The Australian Centre for Tropical Freshwater Research (ACTFR) has been commissioned by the Department of Natural Resources (DNR) to provide an environmental evaluation of prospective dam sites located within the Burdekin Catchment. This exercise is a desk-top study based on existing data sources, with no original information being collected. Prospective dam sites that remain in consideration after this exercise will be subject to more thorough investigations at a later date. The purpose of this exercise is to raise issues that are currently known to exist

Systematic definition of threatened fauna communities is critical to their conservation

Aim: Most terrestrial ecological communities are defined primarily on their constituent flora. We aimed to develop a repeatable approach to defining a community, both intact and degraded, based on its fauna. We demonstrate how the approach can be used to guide conservation—for example, determining whether a multispecies community of animals is threatened. Location: Temperate and subtropical woodlands of Australia. Methods: We used expert opinion to develop a definition of the Australian Temperate and Subtropical Woodland Bird Community and metrics of its condition. Using continental-scale vegetation change mapping, and national bird atlas data, we assessed this community against criteria for listing as a threatened ecological community under national biodiversity conservation law. Results: We defined and described a recognizable and consistent Australian Temperate and Subtropical Woodland Bird Community. Although taxonomically and functionally very similar, we identified six community variants that show species- or genus-level substitutions. The community was evaluated to be Endangered or Critically Endangered across its extent based on criteria from Australia's Environment Protection and Biodiversity Conservation Act 1999. We used a novel metric of condition using historical changes in woodland extent and bird species, to demonstrate the community has declined substantially in geographical extent and integrity and is subject to severe and ongoing threats. Conclusions: The consequences of global change affect entire communities, not just single species; however, defining ecological communities based predominantly on plant species composition can fail to illuminate the complex associations of animals that are both sustained by, and sustain, the vegetation. In this study, we present a process for defining and evaluating the status of a fauna community against threat criteria. The explicit recognition and protection of fauna communities can be an important complement to the protection of plant-based ecological communities

Incorporating low-resolution historic species location data decreases performance of distribution models

Developing robust species distribution models is important as model outputs are increasingly being incorporated into conservation policy and management decisions. A largely overlooked component of model assessment and refinement is whether to include historic species occurrence data in distribution models to increase the data sample size. Data of different temporal provenance often differ in spatial accuracy and precision. We test the effect of inclusion of historic coarse-resolution occurrence data on distribution model outputs for 187 species of birds in Australian tropical savannas. Models using only recent (after 1990), fine-resolution data had significantly higher model performance scores measured with area under the receiver operating characteristic curve (AUC) than models incorporating both fine- and coarse-resolution data. The drop in AUC score is positively correlated with the total area predicted to be suitable for the species (R2 = 0.163–0.187, depending on the environmental predictors in the model), as coarser data generally leads to greater predicted areas. The remaining unexplained variation is likely to be due to the covariate errors resulting from resolution mismatch between species records and environmental predictors. We conclude that decisions regarding data use in species distribution models must be conscious of the variation in predictions that mixed-scale datasets might cause

Assessing vulnerability to climate change: a comprehensive examination of Australian tropical savanna birds

Assessments of species vulnerability to climate change should increase the effectiveness of interventions in the current decline in biodiversity. Species vulnerability to climate change is a consequence of their sensitivity and adaptive capacity, in combination with their exposure to climate change. We apply a vulnerability assessment framework to 243 bird species inhabiting the tropical savannas of northern Australia. We build on previous vulnerability studies by including detailed data for variables relating to species sensitivity to change (relative abundance, clutch size, sensitivity to fire and distribution area), species adaptive capacity (movement behaviour and dietary breadth) and proportional changes predicted for their geographic range (i.e. exposure to climate change). These are integrated to provide a ranking of vulnerability. Our analysis found that birds of Australian tropical savannas cluster together with high sensitivity, with a few wide-ranging increasing species with very low sensitivity. Australian tropical savanna birds have a range of adaptive capacities, and the impact of climate change on these species is predicted to be substantial. Two already endangered species are among the most vulnerable. Species largely restricted to Cape York Peninsula (a geographically distinct region) had the greatest overall vulnerability; these species were, in general, sensitive due to small distributions, sensitivity to fire frequency and had a lower capacity for dispersal. It will be important for the future of Australian tropical savanna birds to mitigate ecological threats and maintain extensive areas of suitable habitat to facilitate species dispersal

Understanding and managing the threats to Night Parrots in south-western Queensland

South-western Queensland supports a suite of threatened native species, including Night Parrots. We investigated why this species has persisted in the region and discovered low prevalence of the typical factors that are thought to explain fauna attrition elsewhere in central Australia. Foxes appear to be completely absent. Feral cats were recorded relatively infrequently and showed a significant preference for habitats less commonly used by Night Parrots, a partition that may be driven by the presence of dogs that were detected twice as frequently as cats. Our study area has had a long history of moderate grazing pressure, which is concentrated mostly in productive alluvial habitats. We detected very few herbivores, and dog scat analyses suggest that macropod populations are regulated by predation. Archival imagery shows that large fires are not a feature of this landscape, resulting in the long-term, stable availability of patchy Triodia habitats separated by natural no-fuel areas. Based on these empirical data, we postulate that low non-native predator pressure, long-term stable availability of Triodia cover and a productive landscape that has had only moderate grazing pressure are the interacting factors that may explain why Night Parrots have persisted in south-western Queensland. We present practical management actions that could enhance the suitability of this landscape for Night Parrots

Beauty in the eye of the beholder: a new species of gecko (Diplodactylidae: Lucasium) from inland north Queensland, Australia

The Einasleigh Uplands biolegion of central north Queensland, Australia, harbours a unique suite of reptiles that have begun to receive significant attention in the last 20 years. This has resulted in a number of new reptile species being described, and recognition that others await description. We describe a new species of Lucasium Wermuth, 1965 from the western Einasleigh Uplands. Lucasium iris sp. nov. is genetically distinct and morphologically diagnosable from all congeners by its large size, long and narrow tail, nares in contact with rostral scale, homogeneous body scales, distinct vertebral stripe. and paired, enlarged, apical subdigital lamellae. It is known from low rocky hills in a localised area of the Gregory Range, has the most restricted known distribution of any Lucasium, and is the only Lucasium endemic to Queensland. The new species appears most closely related to L. steindachneri (Boulenger, 1885), based on mitochondrial DNA sequences, but has a colour-pattern more similar to L. immaculatum Storr, 1988. All three of these species occur in the Einasleigh Uplands, but only L. steindachneri is known to occur in sympatry with L. iris sp. nov. In addition to the description of the new species, we present records of Lucasium immaculatum from the Einasleigh Uplands, which represent a significant known range extension

Yellow-throated miners Manorina flavigula homogenize bird communities across intact and fragmented landscapes

In Australia, the role of noisy miners Manorina melanocephala in biotic homogenization of the avifauna has been well established in modified landscapes, and is listed as a threatening process under national conservation legislation. However, less is known about the effect of the congeneric and more widely distributed yellow-throated miner, M.flavigula. In this paper we investigate the relative roles of habitat loss and increased dominance by the yellow-throated miner in avian homogenization and species functional group decline. We examined bird community data collected from 368 woodland sites across three bioregions. For each site there was a local and a landscape scale measure of remnant vegetation cover. We used both multivariate and regression analysis to test the relative influence of yellow-throated miner abundance and vegetation on bird community composition. There was clear compositional change and homogenization of the avifauna where yellow-throated miners were present and vegetation cover was low. The abundance of 40 bird species was predicted by combinations of vegetation cover or yellow-throated miner abundance, and 31 of these regressions included the term yellow-throated miner. Of these, there was a negative relationship with 23 species, and 19 of these were insectivores or nectarivores. We postulate that the combination of clearing and yellow-throated miner abundance can interact to disrupt the ecological function of woodlands, by the depletion of insect- and nectar-feeding species and the disturbance to mixed feeding flocks. We propose future research objectives that include a continental-scale analysis of the determinants of yellow-throated miner overabundance, the numerical and geographical thresholds of their potential impacts, and the ecological consequences on both avifauna and the woodlands they inhabit