Phylogenetics of the skyhoppers (Kosciuscola) of the Australian Alps : evolutionary and conservation implications

The true biodiversity of Australia's alpine and subalpine endemics is unknown. Genetic studies to date have focused on sub-regions and restricted taxa, but even so, indicate deep divergences across small geographic scales and therefore that the bulk of biodiversity remains to be discovered. We aimed to study the phylogeography of the Australian Alps by focusing on the skyhoppers (Kosciuscola), a genus of five species of flightless grasshoppers whose combined distributions both span the region and are almost exclusively contained within it. Our sampling covered 650 km on the mainland and several sites in Tasmania with total of 260 specimens used to reconstruct a robust phylogeny of Koscisucola. Phylogenies were based on single nucleotide polymorphism data generated from double-digested restriction-associated DNA sequencing. Skyhoppers diverged around 2 million years ago and have since undergone complex diversification seemingly driven by climatic oscillations throughout the Pleistocene. We recovered not 5 but 14 clades indicating the presence of many unknown species. Our results support conspicuous geographic features as genetic breaks; e.g. the Murray Valley, and inconspicuous ones; e.g. between the Bogong High Plains and Mt Hotham. Climate change is progressing quickly in the region and its impact, particularly on snow, could have severe consequences for the skyhoppers' overwinter survival. The true diversity of skyhoppers highlights that biodiversity loss in the Alps as a result of climate change is likely to be far greater than what can be estimated based on current species numbers and that management including small geographical scales is key

Predicting species and community responses to global change using structured expert judgement : an Australian mountain ecosystems case study

Conservation managers are under increasing pressure to make decisions about the allocation of finite resources to protect biodiversity under a changing climate. However, the impacts of climate and global change drivers on species are outpacing our capacity to collect the empirical data necessary to inform these decisions. This is particularly the case in the Australian Alps which has already undergone recent changes in climate and experienced more frequent large-scale bushfires. In lieu of empirical data, we used a structured expert elicitation method (the IDEA protocol) to estimate the abundance and distribution of nine vegetation groups and 89 Australian alpine and subalpine species by the year 2050. Experts predicted that most alpine vegetation communities would decline in extent by 2050; only woodlands and heathlands are predicted to increase in extent. Predicted species-level responses for alpine plants and animals were highly variable and uncertain. In general, alpine plants spanned the range of possible responses, with some expected to increase, decrease or not change in cover. By contrast, almost all animal species are predicted to decline or not change in abundance or elevation range; more species with water-centric life-cycles are expected to decline in abundance than other species. While long-term ecological data will always be the gold-standard in informing the future of biodiversity, the method and outcomes outlined here provide a pragmatic and coherent basis upon which to start informing conservation policy and management in the face of rapid change and paucity of data

Geographic range and the mountain niche: ecology, adaptation and environmental change

© 2015 Dr. Rachel Anna SlatyerThe geographic range is one of the most fundamental traits of a species. For this reason, understanding the ecological and evolutionary drivers of the size, position, and structure of the range is a key research challenge. The geographic range also has an overriding influence on the environments to which a species is exposed and their spatial and temporal variation. This study addresses four questions relevant to understanding interactions between the environment and individuals, populations, species and communities, with a focus on mountain regions where environmental variation is particularly pronounced. First, using meta-analysis and a single-genus case study, I explore the relationship between geographic range size and characteristics of the ecological niche. Range size can vary by several orders of magnitude among closely related species, but is strongly and consistently associated with both niche breadth and niche position: the most widespread species tend to be those with a broader niche and/or those that utilise resources that are common across the landscape. Second, I investigate the relationship between niche and range limits by testing variation in physiological tolerance across environmental gradients in two mountain systems: beetles (Carabidae: Nebria Latreille) from the North American Cascade Range and grasshoppers (Acrididae: Kosciuscola Sjösted) from the Australian Alps. Whereas the Nebria, distributed across a 2000 m elevational gradient, showed almost no variation in thermal tolerance, the Kosciuscola showed significant interspecific variation in cold tolerance, consistent with the decrease in average temperature with elevation. I suggest that cold tolerance limits might constrain the upper range edge of at least one species. Third, I explore how past climate cycles and Australia’s dissected mountain landscape have influenced the population structure of an alpine-endemic grasshopper (Kosciuscola tristis) using a combination of genetic methods. Despite continuity of alpine habitat during Pleistocene glacial cycles and, by global standards, small-scale disjunctions in the present distribution of these environments, K. tristis showed deep lineage divergence associated with geographic breaks in alpine conditions. Fine-scale structure in the absence of clear geographic barriers suggests that habitat heterogeneity might structure populations at a regional scale. The last component of this work tests the response of alpine invertebrate species and communities to reduced winter snow cover. This is a likely future scenario in the Australian high country, where the winter snowpack is already marginal. I show that Australia has a diverse subnivean arthropod fauna, characterised by the high relative abundance of springtails (Collembola), mites (Acari), spiders (Araneae) and beetles (Coleoptera). Experimental reduction of the winter snowpack caused shifts in community composition, driven by a small number of abundant arthropod taxa. These effects were apparent at a small spatial and temporal scale, with rapid recovery from experimental perturbation in spring. Mountain ecosystems are threatened by climate change as they are already rare at a landscape scale, are typically fragmented and have limited scope for climate tracking. The work presented here highlights effects of small-scale environmental variation on species traits, genetic structure and communities, which could act to either buffer or exacerbate landscape-scale climatic changes

Desiccation resistance in Nebria

<p>Water loss rates for 12 <em>Nebria </em>species<em> </em>and <em>Nippononebria campbelli </em>on Mt Rainier, under two temperature and humidity treatments.</p

Ecological effects of snow conditions database

Database of 257 papers supporting a systematic quantative review on the effects of changing snow conditions on aboveground organisms

Critical thermal limits in Nebria

<p>Critical thermal minimum and maximum for <em>Nebria </em>and <em>Nippononebria campbelli </em>on Mt Rainier, Washington, USA. </p

Montane Collembola at risk from climate change in Australia

Collembola are an important component of montane arthropod communities worldwide, where they are often the most abundant and active group. In Australia, montane ecosystems are predicted to contract with continued climate warming, yet little is known about the faunal composition of Collembola on mountains nor its level of endemism. We compared the composition of Collembola communities from five mountain summits along a latitudinal gradient in eastern Australia. Each mountain harboured a distinct Collembola community, with few shared species/morphospecies. Even at the genus and family level, however, mountains varied considerably in faunal composition. Although no latitudinal trends were detected, short range endemism of morphospecies was high. Year-to-year variation in community composition within sites was small compared to between-site variation, even when collections were made 10 years apart. These results suggest that montane Collembola taxa may be resilient, as far as short term variations in weather are concerned. However, there is no evidence as to whether longer-lasting warmer conditions would be tolerated. If not, large scale losses of locally endemic species but not genera, unless they are monobasic, are likely