School of BioSciences - Theses
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ItemFeasibility of bacterial probiotics for mitigating coral bleaching( 2020)Given the increasing frequency of climate change driven coral mass bleaching and mass mortality events, intervention strategies aimed at enhancing coral thermal tolerance (assisted evolution) are urgently needed in addition to strong action to reduce carbon emissions. Without such interventions, coral reefs will not survive. The seven chapters in my thesis explore the feasibility of using a host-sourced bacterial probiotic to mitigate bleaching starting with a history of reactive oxygen species (ROS) as a biological explanation for bleaching (Chapter 1). In part because of the difficulty to experimentally manipulate corals post-bleaching, I use Great Barrier Reef (GBR)-sourced Exaiptasia diaphana as a model organism for this system, which I describe in Chapter 2. The comparatively high levels of physiological and genetic variability among GBR anemone genotypes make these animals representatives of global E. diaphana diversity and thus excellent model organisms. The ‘oxidative stress theory for coral bleaching’ provides rationale for the development of a probiotic with a high free radical scavenging ability. In Chapter 3, I construct a probiotic comprised of E. diaphana-associated bacteria able to reduce oxidative stress by neutralizing free radicals such as ROS. I identified six strains with high free radical scavenging ability belonging to the families Alteromonadaceae, Rhodobacteraceae, Flavobacteriaceae, and Micrococcaceae. In parallel, I established a “negative” probiotic consisting of closely related strains with poor free radical scavenging capacities. The application of this probiotic to mitigate the negative impacts of exposure to a simulated heat wave was tested in Chapter 4. There was no evidence for improved thermal tolerance in E. diaphana. Changes in the relative abundance of anemone-sourced Labrenzia provided evidence for its integration in the E. diaphana microbiome. Uptake of other probiotic members was inconsistent and probiotic members did not persist in the anemone microbiome over time. Consequently, the failure of the probiotic inoculation to confer improved thermal tolerance may have been due to the absence of probiotic bacteria for the full duration of the experiment. Importantly, there were no apparent physiological impacts on the holobiont following inoculation, thus showing that shifting the abundance of native anemone microbiome members was not detrimental to holobiont health. Further, I found no evidence for an increase in ROS in the E. diaphana holobiont when it was exposed to heat. Some of the most compelling evidence in support of the ‘oxidative stress theory of coral bleaching’ comes from three published studies that expose corals, cultures of their algal endosymbiont, or E. diaphana to exogenous antioxidants during thermal stress. To confirm that ROS is the main driver behind thermal bleaching in E. diaphana, I replicated these previous experiments with novel methods that allowed a more accurate quantitation of ROS, and found that dosing with exogenous antioxidants (mannitol and ascorbate plus catalase) mitigates bleaching in E. diaphana, with no correlation between bleaching and increased ROS (Chapter 5). A serendipitous finding was that the E. diaphana bacterial community diversity can be rapidly reduced when anemones are reared in sterile seawater, making this model suitable for testing the efficacy of microbial restructuring strategies (Chapter 6). Taken together, the work from my PhD has shown that ROS scavenging varies among anemone-associated bacteria and that a high ROS-scavenging probiotic can be developed. Further, my findings have unveiled several main knowledge gaps that need to be filled before probiotics can be implemented, including administration strategies and choice of probiotic bacteria that maximise the maintenance of probiotic communities over time and a direct measurements of ROS in bleaching corals (Chapter 7).
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ItemInterspecific hybridization as a tool for enhancing climate resilience of reef-building corals( 2018)The world’s coral reefs are facing unprecedented changes in temperature and carbonate chemistry caused by the increasing concentration of atmospheric CO2. Recent massive loss of corals across the world suggests that their rate of adaptation and/or acclimatization is unlikely fast enough to keep pace with climate change. This thesis examines interspecific hybridization as a conservation management tool to develop coral stock with enhanced climate resilience and adaptive potential. I start this thesis by discussing the potential benefits and risks of hybridization, and exploring the legal framework associated with hybrids and hybridization (chapter 1). Next, I present the results of interspecific fertilization trials, as well as stress experiments on coral larvae (chapter 2) and recruits (chapter 3) conducted to compare fitness of purebred and hybrid offspring. To understand mechanisms that may have contributed to the observed holobiont fitness differences, bacterial and algal endosymbiont communities associated with these corals were examined using 16S rRNA gene and ITS2 metabarcoding (chapter 4), and coral host gene expression patterns were assessed using RNA sequencing (chapter 5). The following findings and key conclusions have emerged from this thesis. Firstly, all four tested pairs of Acropora species from the Great Barrier Reef were cross-fertile, but the degree of prezygotic barriers varied (chapters 2, 3). In both years in which hybridization was attempted (2015, 2016), the majority of the target species pairs had no or limited temporal isolation (i.e., similar spawning dates and times). The only clear temporal isolation was between the ‘early spawner’ A. tenuis and the ‘late spawner’, A. loripes, although their gametes were still compatible. Gametic incompatibility varied between species pairs and the year of hybridization tests (which involved the same coral species collected from different locations). Levels of cross fertility ranged from no prezygotic barriers in both directions (chapter 3), to successful fertilization in one direction only, and in once case, unsuccessful fertilization in both directions (chapter 2). The observed variations in gametic incompatibility may be a consequence of differences in gamete-gamete recognition molecules. Secondly, hybrid corals were generally as fit as or more fit than parental purebred species (chapters 2, 3). At the embryonic stage, hybrid embryos developed normally and at similar rates as purebred embryos (chapter 3). At the larval stage, survival and settlement of hybrid larvae under 10 days exposure to ambient and elevated temperatures were mostly similar to that of purebreds, but higher than purebreds in a small number of cases (chapter 2). Hybrid recruits also had similar algal endosymbiont uptake rates and photochemical efficiency as that of purebred recruits (chapter 3). Under seven months exposure to ambient and elevated temperature and pCO2 conditions, however, some hybrids showed higher survival and grew larger than parental purebred species under both conditions (chapter 3). Overall, maternal effects were observed in hybrids of the A. tenuis x A. loripes cross (i.e., hybrids had similar fitness to the maternal parent species), and over-dominance in hybrids of the A. sarmentosa x A. florida cross (i.e., hybrids had higher fitness than both parental species), with some variations between traits and treatment conditions. While fitness of these hybrids in the field and their reproductive potential are yet to be investigated, these findings provide proof-of concept that interspecific hybridization may enhance coral resilience and this approach may therefore increase the success of coral reef restoration programs. Thirdly, the observed holobiont fitness differences between offspring groups were likely due to host-related factors (chapter 5), but not the microbial communities associated with these corals (chapter 4). No differences in the bacterial and microalgal endosymbiont community composition were found between hybrid and purebred corals (chapter 4). Microbial communities of these seven months old recruits were highly diverse and lacked host specificity. Winnowing of the communities occurred over time, resulting in less diverse microbial communities that differed between the two species pair crosses by two years of age. Transcriptome-wide gene expression analysis for the A. tenuis x A. loripes cross showed clear maternal patterns (chapter 5), consistent with the observed fitness results. Hybrids had similar gene expression patterns to their material parents, and only up to 10 differentially expressed genes were observed between them. In contrast, hundreds of genes were found differentially expressed between purebred A. tenuis and A. loripes, as well as between hybrids that had different maternal parents. Due to insufficient material available for the A. sarmentosa x A. florida cross at the end of the seven months aquarium experiment, transcriptome analysis was not conducted for this cross. Findings from this thesis support the notion that interspecific hybridization may improve coral resilience and facilitate adaptation to climate change. Further, as genetic diversity within species is predicted to decline as a consequence of high mortality disturbances such as mass bleaching events, interspecific hybridization can be used to restore losses in genetic diversity. If future studies can demonstrate high fitness of hybrid corals in the field and in advanced generations, hybrid corals may serve as a stock for reef managers for reseeding degraded reefs and/or enhancing resilience of healthy reefs.
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ItemExploring adaptation in a key Australian genus Brachyscome through experimentation( 2017)This thesis focuses on species adaptation in a key Australian genus Brachyscome, using three central themes in ecological theory; plants perform better where they naturally occur (local adaptation), widespread species outperform narrow endemics (niche breadth—range size hypothesis), and warming responses and range size (related species show ecological similarity). This study incorporates a broad ecological and experimental approach to test these three hypotheses. This approach involves combining reciprocal field based designs with a common garden comparison, and a multispecies common garden with a warming treatment. Firstly, under a combined reciprocal and common garden approach, and using different populations (at the seedling stage) of broadly distributed B. decipiens I questioned whether there was a ‘home site advantage’ with the hypothesis of populations showing greater fitness at their sites of origin. I had undertaken prior survey work which indicated significant morphological variation between different populations. When tested in a reciprocal design this was not the case, and no local adaptation was detected, and further to this, no variation between populations was detected in the common garden comparison. Keeping the same reciprocal and common garden approach and increasing the study species so that I now had a related group, I explored the niche breadth— range size hypothesis at the seed and seedling stage of plant development. I predicted species that naturally occurred over a greater area were more likely to show a higher performance in terms of survival and growth than species with a restricted range in novel environments, and further restricted species would show higher performance at their site of origin due to their specialised habitat preferences. I found performance came at a cost to survival in three of the widespread species, and the opposite pattern in two of the narrow endemic species. A trade off may exist. The niche breadth—range size hypothesis was partially supported, given one species with the most restricted range showed a similar response to the widespread species. So, although we found a pattern, an exception to this also exists. Moving beyond the alpine environment, I used a common garden approach with a treatment to explore species responses to warming. I extended my study species to nineteen Brachyscome taxa under the following criteria; 1) only occur in an alpine zone, 2) occur in and beyond an alpine zone and 3) do not occur in an alpine zone. I predicted species would show a phylogenetic signature for warm temperature responses, and that alpine species would be particularly susceptible to the treatment. Findings suggest species which were endemic to alpine areas were less likely to benefit from warming than widespread species. I found evolutionary history did not have a detectable effect on warming responses. While there was a moderate phylogenetic signal for plant growth in the absence of warming, there was no signal for growth changes in response to warming, despite variability among species that ranged from positive to negative growth responses to warming. There was also no strong effect of ecological context, as species that showed a positive response to warming did not necessarily originate from hotter environments. In fact, several species originating from hot environments grew relatively poorly when exposed to higher soil temperature. We found a strong phylogenetic signal suggesting that closely related species tend to occur in areas with similar annual variability in precipitation. As Brachyscome is an iconic Australian genus of ~80 species of daisies with very few in cultivation, I included one widely cultivated species Brachyscome multifida (because it had already demonstrated horticultural potential) to explore the horticulture potential of species which responded positively to warming. Brachyscome stuartii, and B. rigidula, both compact plants with attractive foliage, showed horticultural potential under warmer soil conditions, as did B multifida, supporting its popularity as an ornamental cultivar. Brachyscome is an intriguing group of daisies that can be found across a myriad of habitats in the Australian landscape. Tapping into this complex group by taking representatives from across diverse clades to address the three ecological concepts, this thesis helps build our understanding of local adaptation and variation in alpine systems, and helps in the identification of correlates of species performance under warming within the context of the niche—breadth and range size hypotheses. It highlights how plants might be selected that respond positively to our changing climate.
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ItemClimate adaptation in Eucalyptus microcarpa (Grey Box) and implications for conservation( 2017)Restoration is an important component of conservation management, especially in highly modified landscapes. In the face of rapid environmental change, the mere presence of vegetation doesn’t necessarily equate to the long term sustainability of populations. Rather, there is a need to consider evolutionary potential in conservation planning, including restoration. This thesis investigates two key components of evolutionary potential pertinent to restoration – namely genetic diversity and climate adaptation – in an important restoration tree species in south-eastern Australia, Eucalyptus microcarpa. This thesis aims to understand how genetic diversity and local adaptation are distributed across the range of E. microcarpa and how this knowledge may help inform seed sourcing and enhance resilience of restoration plantings under climate change. To begin, I use a landscape genomic approach to explore genomic diversity in E. microcarpa and how diversity in small habitat remnants and revegetation (restored) sites compare to large remnants. This work found that small, habitat remnants and revegetation sites largely, but not completely captured patterns of genomic diversity across the landscape. Whilst overall genomic diversity was similar between site types, patterns of diversity across the genome varied between site types. These results suggest important genomic differences between site types that may influence future adaptive potential of revegetation sites and small habitat remnants. I then investigated adaptation to climate in E. microcarpa using multiple approaches. Firstly, using a landscape genomic approach, I found evidence of genomic climate adaptation in E. microcarpa. These results suggest climate adaptation to be a genome-wide phenomenon, involving many genes and genomic regions. Exploration of genomic changes that may be required to match projected climate change suggest adaptation to be via shifts in allele frequency from standing variation. In addition to suggesting a number of climate variables associated with adaptation in E. microcarpa, these results highlight the importance of genetic diversity and standing variation for maintaining adaptive potential. Utilising existing genetic resources for this species, I found evidence of heritable, genetic variation in growth and leaf traits of E. microcarpa growing in a provenance trial. Furthermore, significant trait variation between provenances and associations with climate variables suggest climate as a driver of adaptive differences. Finally, I combined the independent genomic and phenotypic analyses to provide stronger support for climate adaptation in E. microcarpa, including links between genomic variants and adaptive traits. Associations between traits and single nucleotide polymorphisms (SNPs) using putatively adaptive SNPs genotyped in provenance trial trees validated genomic results, suggesting some trait variation could be explained by these SNPs. Furthermore, links between all three sources of variation relevant to local adaptation – genotype, phenotype and climate – corroborated findings of the two independent analyses. This approach therefore provides greater support for adaptation to climate in E. microcarpa. Together these analyses address the current genetic state of restoration in E. microcarpa as well as the structure of genetic diversity and climate adaptation across its distribution. These results suggest adaptive differences within E. microcarpa that could be utilised to enhance evolutionary potential within restoration plantings.
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ItemA genetic approach to the conservation of holly leaf grevilleas (Proteaceae)( 2016)The holly leaf grevilleas consist of an informal aggregate of 15 species found in south-eastern Australia. The group exhibits high levels of morphological variation and the most widespread species, Grevillea aquifoilum Lindl., is also the most variable. Most species are restricted endemics and their geographic limits make them vulnerable to the effects of fragmentation and environmental change. In some species, production of viable seed is unknown or has not been confirmed. Identifying factors that contribute to the persistence of species when fecundity is low is of critical importance to their conservation. Here, a phylogenetic analysis is used to clarify the evolutionary relationships among lineages within the holly leaf grevilleas. The lineages identified are then the basis of chapters 4 – 6 that address questions of what constitutes the units of conservation and how clonal plants should be assessed. Analysis of 12 cpDNA regions strongly supported the more southerly distributed holly leaf grevilleas as a monophyletic group comprising four clades (‘G. aquifolium’, ‘G. dryophylla’, ‘G. repens’, ‘G. ilicifolia’). The two northern holly leaf grevillea species, G. renwickiana and G. scortechinii, found in New South Wales and southern Queensland, were not positioned with the southern species but their relationship with outgroup species G. willisii from northeastern Victoria and G. acanthifolia and G. laurifolia from New South Wales could not be ascertained with confidence. Two nuclear regions, PHYA and waxy1, were less variable and not analysed in combination with cpDNA. PHYA was largely uninformative with most species forming a polytomy. Two major variants were identified in waxy1 and consisted of one functional and one non-functional copy based on DNA translation. Minor alleles of functional and non-functional copies were present in some accessions. Using only the functional copy (including multiple alleles when present), the southern ‘G. ilicifolia’ clade, as identified from cpDNA, was clearly differentiated from the northern clade and the remaining species. Within the southern species, those not belonging to the ‘G. ilicifolia’ clade were grouped together but clades identified in the cpDNA phylogeny were not recovered in the waxy1 analysis. Incongruence between the phylogenetic placement of some taxa and current species assignment based on morphology, including apparent paraphyly of G. aquifolium, may indicate an evolutionary history of hybridisation, introgression and incomplete lineage sorting and/or the use of morphological characters that are not lineage-specific. For example, the two subspecies of G. montis-cole differentiated morphologically on the basis of style-length are positioned in different clades and warrant specific rank if supported with nuclear data, and G. steiglitziana is split between two lineages within the southern ‘G. dryophylla’ clade. The phylogenetic placement of G. ‘williamsonii’, a taxon no longer recognised, with sympatric G. aquifolium, coupled with microsatellite analysis supports the current taxonomic view of its synonymy with G. aquifolium. The cpDNA phylogeney also raises questions about the taxonomy of G. microstegia and G. bedggoodiana, taxa that are also positioned with G. aquifolium in the ‘G. aquifolium’ clade. Population genetic analyses of G. infecunda and G. renwickiana found both species to be comprised of a small number of clonal lineages with no evidence of contemporary sexual reproduction. Within species, no clones were found at multiple locations and cpDNA haplotypes were derived from single lineages. In G. infecunda, 38 clonal lineages were identified from a microsatellite analysis of 280 samples from 11 populations. The number of clones present per population ranged from 1 to 11 and clone size varied from a single stem to several hectares. In G. renwickiana, analysis of 197 samples revealed that all but one of seven populations were monoclonal. Clones were distributed over a minimum area of one hectare. Sequencing of microsatellite alleles showed that variation in allele size profiles among clonemates could be interpreted as somatic mutation. The genetic patterns evident in the two species are likely to be the result of a loss of sexual reproduction, due to pollen sterility in G. infecunda and the effects of triploidy in G. renwickiana. For the clonal taxa, G. infecunda and G. renwickiana, lack of sexual reproduction leaves little opportunity for adaptation or migration in response to changing conditions. However, to facilitate the adaptive responses of ecological communities rather than individual species, conservation should encompass obligately clonal species because of their role, albeit finite, in mitigating ecological instability as floras respond to rapidly changing environments.
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ItemRobust prediction and decision strategies for managing extinction risks under climate change( 2016)Effective management of biodiversity requires decision strategies that are robust to the uncertainty embodied in predictions of habitat suitability and environmental change. This is particularly relevant in the context of climate change, which may interact with existing threats in unexpected ways. Predictive modelling has become important for addressing questions about climate change impacts. In particular, correlative species distribution models (SDMs) are popular for predicting species' fates, and have been noted as effective tools for guiding conservation decisions. However, SDM predictions are uncertain due to our imperfect understanding of the processes underlying species-environment associations, and, crucially, imprecision in predictions of regional climate change. While this is widely recognised, SDM prediction uncertainty is frequently overlooked, and practical approaches to handling this uncertainty are rare. When SDMs are used to investigate questions of species' persistence during times of environmental change, failure to consider uncertainty about the arrangement and quality of habitat may lead to flawed inferences and ineffective management. It is therefore essential that we improve our understanding of key uncertainties, and develop methods that explicitly handle uncertainty in a way that promotes sensible management decisions. In this thesis, I explore these issues through case studies of the mountain pygmy-possum, Burramys parvus, in the alpine region of south-eastern Australia. I draw on a range of quantitative tools and classical decision theory to: (1) determine the magnitude of uncertainty about habitat suitability due to SDM predictor choice, and how this varies under climate change; (2) develop a framework for identifying the optimal spatial allocation of resources for species' conservation under climate change, given uncertain predictions of habitat suitability; (3) explore the utility of abundance time series for improving our understanding of environmental dynamics influencing populations; (4) combine SDMs and models of population dynamics with decision theory to assess the extent to which predictions are refined by explicitly including population processes; and (5) develop a suite of open source software tools that facilitate common ecological modelling tasks, making rigorous investigation of climate change questions more computationally efficient and feasible. I found that standard approaches to model evaluation obscure key differences amongst competing SDMs, suggesting that consideration of ecological relevance during model construction is essential. I showed that despite extensive uncertainty about future habitat, conservation actions can be prioritised in a way that reflects managers' appetites for risk and reward. I demonstrated that for spatially-structured populations, hierarchical models can reveal the spatial scales at which environmental processes control population growth. Regional synchrony in population dynamics is evident for B. parvus, but local, density-independent environmental forces are more important in determining abundance trajectories. Finally, I demonstrated that habitat change is an unreliable surrogate for a species' response to climate change. Predictions about the distribution and quality of future habitat for B. parvus are uncertain. However, this is an inevitable challenge when forecasting species' fates. Importantly, it does not preclude effective management. The way forward is to recognise and account for uncertainty in ecological models, thereby enabling sensible conservation decisions for species impacted by climate change.
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ItemParasitism by Trichogramma wasp: potential and reality under climate change scenario, with focus species attacking Asian corn borer( 2016)Climate change may directly influence the distribution of parasitoids, lead to phenological asynchrony with their hosts, and/or lead to other disruptions of multitrophic interactions. By determining the impacts of global warming effects which may influence Trichogramma populations, researchers and land users can be provided with ways to further enhance the efficiency of biocontrol. First, I identified common Trichogramma species emerging from Asian corn borer Ostrinia furnacalis egg masses (based on morphology and internal transcribed spacer 2- ITS-2) throughout southwestern Taiwan. I then compared their life history characteristics and thermal limits and determined the Wolbachia infection status of field-collected parasitoids. Although T. ostriniae and T. sp. y appear to be morphologically similar, the ITS-2 identity between these two taxa is only 89%. A commercially released Trichogramma colony thought to be T. chilonis possessed 99% identity with the field T. sp. y individuals. The current study provides a baseline for future work, and also highlights the importance of accurately identifying species when establishing colonies of natural enemies for biocontrol. Next, I evaluated the distributions of Trichogramma ostriniae and its native host, Ostrinia furnacalis (in southeastern Asia), and target host, Ostrinia nubilalis (in North America), using a combination of MAXENT and CLIMEX modelling approaches. Trichogramma ostriniae was predicted to occur in the summer corn region of China, with distribution limits linked to its sensitivity to cold, and the seasonality of radiation and precipitation. The stepwise modelling approach used here proved useful for assessing environmental factors linked to an egg parasitoid and its lepidopteran host and for identifying areas potentially suitable for inundative releases. Finally, integrating meta-analysis results and reviewing related literature, indicated that both top-down and bottom-up factors could moderate the effect size of egg parasitoids over a range of Extreme High Temperature (EHT) values. These patterns suggest a complex response to climate change, mediated by temperature factors, precipitation seasonality, crop type and perhaps other factors related to latitude. Trichogramma biocontrol efficiency is hampered by extreme climate change as they are more senstive to environmental factors than their hosts. The work presented here highlights effects of precipitation and radiation seasonality on parasitism, life history traits, and distributions of Trichogramma species, which could act to either improve or optimise the execution of lepidopteran biocontrol projects. Results of this study will be useful to managers for successful use of Trichogramma in biocontrol under a climate change future.
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ItemGeographic range and the mountain niche: ecology, adaptation and environmental change( 2015)The 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.