Dispersal involves the movement of individuals between established populations or colonisation of uninhabited areas and is a key organising process underpinning patterns in populations and communities. Dispersal is a fundamental component of metapopulation and metacommunity theory, central to explaining the underlying the patterns of abundance and distribution of species, both spatially and temporally. Furthermore, dispersal is a main determinant of community assembly, governing how communities are constructed and maintained through immigration. Barriers that limit or prevent species from dispersing to a location can have a major influence on population dynamics and how communities assemble. In a restoration context, this can result in delayed or poor restoration outcomes due to a lack of dispersing colonists preventing colonisation. In freshwater environments, one key hypothesis describing how dams and weirs affect rivers is that they disrupt longitudinal connectivity, fragmenting river ecosystems, potentially limiting dispersal of biota along rivers. In this thesis, I asked three main questions: 1) Are there natural barriers to dispersal in advective systems? 2) Do artificial barriers hinder dispersal more than natural barriers? 3) Do artificial barriers constrain dispersal in ways that affect population and communities, especially community assembly? The study focused on rivers located mostly within Kosciuszko National Park, in the Snowy Mountains region of south-east Australia. Many rivers in this area are affected by the Snowy Mountains Hydro-electric Scheme and associated culverts, weirs and dams, which capture and divert numerous alpine and montane streams, severing flow connections between much of the Snowy River catchment and its headwaters. First, I tested how species dispersal between suitable habitats was influenced by the characteristics of the intervening matrix of unsuitable habitat. Specifically, I examined whether stream insect drift was constrained by natural river features, potentially limiting connectivity within rivers. I found that natural, slow moving pools may limit the connectivity of benthic invertebrate populations in rivers by reducing drift rates between riffle habitats. Furthermore, I determined that the hydraulic conditions within a pool limit drift dispersal and total distance between riffle habitat patches was not an important factor in limiting dispersal via drift. Secondly, I tested whether species dispersal was constrained by a human-made barrier, potentially limiting connectivity between populations more than natural landscape structures. In a natural river system, I studied whether a weir and associated pool reduced the drift rates of insects to a greater degree than natural pools. This component addressed a major knowledge gap about the effect of weir structures on downstream dispersal of stream biota. The weir consistently reduced numbers of drifting insects for 3 of 4 study taxa, exceeding the reduction of drifters in natural pools. The morphology of the weir pool was substantially deeper and wider and slower than the majority of studied natural pools. The combined effects of much lower average water velocity, multiple large low velocity areas within the weir pool and the weir wall were likely to be central causes of the reduction stream insect drift through the weir. Lastly, in a multi-year study, I tested whether and how the removal of dispersal constraints affected community assembly in new habitats and whether changed dispersal can alter existing communities. In this study, I investigated the patterns and mechanisms of freshwater invertebrate community assembly after the reintroduction of water to 2 streams downstream of weirs that were previously dry for over 50 years. Colonisation of the newly formed habitat in the tributaries downstream of the weirs was rapid and strongly influenced by dispersal via drift from upstream. Even with some dispersal constraint via reduced drift rates, the new communities rapidly resembled unimpacted communities that were the source of colonists. In the regulated rivers, a reduction in environmental constraints had a much greater influence on the trophic structure of established communities than increased dispersal from the newly formed community in the tributaries. Collectively, this research has overturned important, pre-existing assumptions about dispersal in advective systems by identifying and quantifying the influence of different types of barriers on movement and the effect of altered dispersal rates on community assembly. This information can inform the development of river restoration strategies in rivers affected by weirs and dams and elucidate how and why restoration measures may have been unsuccessful in the past.

This research examines the role and position of the diverse organisations who provide support to people from refugee backgrounds settling in Australia. Non-state organisations in similar contexts have been conceptualised in uneven ways, with previous work understanding them to be ‘filling the gaps’ left by the retraction of the state under neoliberalism, or as working as a shadows-state apparatus. This research challenges such restrictive framings. Engaging with a feminist ethic of care, the research extends geographic literatures that have shown the capacity for organisations to resist and rework repressive influences from the state. Drawing on interviews with a range of organisations across Melbourne, Australia, including community organisations, local governments, faith-based organisations, and generalist charities, the research argues that non-state organisations are indispensable within the settlement landscape in Australia. It highlights the ways in which these organisations both provide people from refugee communities with essential services and resources, and undertake bridging work that allows the state to maintain a restricted and inaccessible approach to social service delivery. It also argues that non-state organisations are active agents in the construction of an expanded citizenship for people from refugee backgrounds, that moves beyond normative and exclusionary imaginaries of Australian citizenship upheld by immigration and settlement policy. Importantly and more broadly, the research shows how a feminist ethic of care informs and shapes the practices of these organisations, offering care-full inclusion in the face of care-less approaches to migration and refugee resettlement in Australia and globally.

In the ecological modernization of China, how firms respond to environmental constraints ought to be investigated to inform environmental reform in China. In industrial water management in particular, socio-economic development in China is boosting industrial water demand, yet water scarcity, severe in the drier north, has exacerbated the conflict between this natural resource and industrial need. While the Chinese government initiated various engineering projects, the largest being the South to North Water Transfer Project, to increase water supply in areas of demand, better management (e.g. changing consumption, reuse and recycling etc.) is argued to be of more urgency and sustainability in China. Positive changes in people’s values, attitudes and behaviours towards water could lead to efficient use of this limited resource. Therefore, this thesis takes a behavioural approach to investigate water management strategies in North China industrial organizations through the lens of ecological modernization. Empirical research is based on firms located in two regions, Beijing and Hebei. It investigates how industrial firms, one of the major market actors in ecological modernization, respond to both physical and regulatory environmental constraints. The methods used are primarily qualitative: semi-structured in-depth interviews and direct observation, supported by secondary data collection. The physical and institutional water availability in the study areas is firstly assessed. Then firm strategies in water management that patterned organizational behaviour are identified. Through analyzing strategies in different firms, the impact of firms’ own characteristics within their borders and the impact of locality attributes are disentangled. The thesis demonstrates ecological modernization a useful tool for understanding water management in China. It finds that North China’s industries are faced with both physical and regulatory water stress, though current prices fail to regulate industrial consumption. Environmental and institutional circumstances are driving environmental upgrading in this region. Firm-level adaptations featuring both upgrading and downgrading strategies include innovation, relocation, outsourcing, factory closure and rule breaking, depending on firm capabilities and orientations. I further argue that both firm characteristics (ownership, size/scale, financial status, market position, and sectoral character etc.) and locality factors (infrastructure and institution) play significant roles in shaping firm behaviour in water management, while interacting with each other. By building a tentative analytical framework to analyze the impact of firms’ own characteristics and locality on firms’ water strategy, this study contributes to both management and geographical theories within the framework of Chinese ecological modernization. And through the empirical analysis, water management suggestions for decision makers in both state and enterprise level are given.

The European Union’s (EU) Renewable Energy Directive (RED) establishes a renewable energy target of 20 per cent by 2020, with binding national targets allocated to each member state. The RED is an important component of the EU's longer-term ambition to reduce greenhouse gas emission by at least 80 per cent by 2050. However, implementation of the Directive has been uneven across the 28 member states, potentially undermining the EU’s long-term objectives and its claims to international climate leadership. This thesis examines the Europeanization of the RED in France and the UK with a specific focus on the electricity sectors of the two countries. It compares the implementation of the renewable energy targets in the highly concentrated, state-controlled French sector with the liberalised UK sector. It identifies the drivers of, and impediments to, the effective implementation of the Directive in the two countries with a particular emphasis on the role of state institutions.

Rivers can experience sudden pulses of sediment, from human and natural erosion processes, that can accumulate in the bed. Abundant studies have examined the sources and dynamics of bedload pulses, and problems they cause, particularly flooding, avulsions, and habitat simplification. Much less has been written about what managers can do about bedload pulses. This thesis examines the use of in-stream extraction to accelerate the recovery of sand-bed rivers impacted by pulses of bedload sediment. This thesis investigates the use of in-stream extraction by developing three conceptual models, and then testing each model in the Glenelg River catchment, SE Australia. The conceptual models are (1) bedload pulse dynamics at the catchment scale, (2) reach scale response of a river to a sequence of extraction pits, and (3) how a river responds to multiple interacting interventions at the tail of a bedload pulse. This thesis uses repeat channel surveys, hydraulic and sediment transport modelling, UAV surveys, geomorphic mapping and interviews with extractors to evaluate the conceptual models. Bedload pulses in the Glenelg River do not behave as migrating waves. Instead, sediment accumulates upstream of valley constrictions and a series of standing waves emerge along the river. Wave crests are static, but sediment is exchanged between each of the waves during floods. At the centennial timescale standing waves are eroded one after another, from upstream to downstream, so that their overall behaviour resembles a single, catchment-wide Aggradation Degradation Episode. Extraction pits did not refill with sediment solely by migration of the upstream end. Instead, pit refill is discharge dependant. At bankfull discharge a zone of bedload transport forms between the migrating pit head and the tail of the pit. At the same time a lobe of suspended sediment intrudes into the pit, depositing sediment on the bed of the pit and along the margins of the pit. Point bar rebuilding is controlled by the pattern of secondary circulation in low angle meander bends, and by recirculating eddies on sharp mender bends. A series of extraction pits excavated along a reach interact and cause erosion in downstream reaches. Thalweg erosion increases in a downstream direction, but the presence of in-stream vegetation (Phragmites australis) causes a greater increase in channel complexity than extraction alone. Extraction prevents existing pools from infill but does not cause new pools to scour on the outside of meander bends. A particularly surprising finding of this thesis was that in reaches at the tail of a bedload pulse, where the source of sediment has already been controlled, local-scale interventions can produce highly localised recovery. In-stream vegetation is a key component of the sequence-of-pools morphology that forms in reaches where stock have been excluded. Reaches at the tail of a bedload pulse do not interact, but become disconnected, which is in direct contrast to existing paradigms of rivers as connected systems. Managers can use these results to decide if, where and how in-stream extraction can be used to accelerate recovery in sand-bed rivers impacted by a bedload pulse.

This thesis is about the ontological intersections and inequalities that emerge as initiatives to manage global environmental problems, such as the Reducing Emissions from Deforestation and Forest Degradation (REDD+) program, are translated locally in Papua New Guinea (PNG). It explores the frictions – awkward, unstable and unequal encounters – that are produced, and in turn move forward, different forms of environmental governance as they intersect with local lives in Suau, Milne Bay Province. I examine REDD+, and similarly the Cool Earth conservation program, as governance assemblages: constantly emerging and shifting networks of heterogeneous relations and elements coming together that necessarily impose power to foreground certain assumptions about reality. Through ethnographic fieldwork with communities implicated in the Central Suau REDD+ Pilot Project and a Cool Earth project, I focus on the stories people in Suau tell of climate change, land and trees, and how these stories come into friction with assumptions that underpin approaches to climate change mitigation and conservation. By engaging with Suau forms of knowledge transmission, including pilipili dai (storytelling), this work makes new contributions to how political ontology is practiced, thereby proposing ways of doing political ecology differently and engaging with decolonial research agendas. Rather than constructing ontologies as bounded, discrete entities, this thesis recognises the multiplicity of ontological assumptions intersecting and competing for primacy, as well as the politics involved in privileging certain assumptions over others. What is at stake here is not just the management of resources and livelihoods, but the very ways different people perceive and perform their realities. The core of this thesis is about inequality. It asks how the foregrounding and marginalising of assumptions enables and constrains different forms of environmental governance that may generate and reinscribe inequalities – not just inequalities between actors, but inequalities between different ways of being and knowing. By opening up space for other ways of perceiving and performing reality, this thesis works to enable different, potentially more equal, approaches to addressing environmental problems.

This thesis examines how young men in north India grappled with the challenges of being educated yet unemployed. It draws on ten months of ethnographic fieldwork conducted in the north Indian state of Uttarakhand to show the distinct ways that mobile youth sought to produce social, economic and cultural capital. When they completed their degrees, many participants migrated from villages and a small township in the Uttarakhand hills, to a regional city to prepare for employment and to find work. These young men endured prolonged unemployment. Yet despite not finding secure jobs, some of these young men drew on their skills and competencies to create work in the private education sector. Other migrants sought to stand out by performing “rural” identities in urban settings, and “urban” identities in rural ones to consolidate their status. Another set of educated youth chose not to migrate but were trying to configure ways of being productive in rural spaces. Some of these young men “hung out” at a computer shop and developed ways of cultivating “good reputations,” others were attempting to create positive social change in villages by volunteering alongside NGOs and by tutoring young children. By drawing theories of social reproduction into conversation with debates about migration and mobility, this research advances understandings of youth, education and migration in the Global South. I argue that educated young men were attempting to leverage their credentials to realise status and respect without compromising their social affiliations and ties. In a context of widespread unemployment and migration, this in an important strategy for leaving open the possibility of rural and urban futures. The research also shows how young men engaged with derogatory constructions of the Uttarakhand hills. While attending to the significant ways that rural areas have been transformed, I argue that educated youth both invoked and challenged these representations in ways that sometimes consolidated their status.

The movement of organisms and material between adjacent ecosystems is a ubiquitous process. Over the last three decades, many works have uncovered factors that influence the flux of spatial subsidies. The emergence of new ecosystems via riparian vegetation clearance, for instance, can impact the quantity and quality of the spatial subsidies that move between perennial streams and riparian zones, and this likely incurs complex responses from riparian consumers. This thesis asks two main questions: 1) how does environmental variables in both the donor (streams) and recipient (riparian zones) systems as a result of riparian vegetation clearance impact the relative quantity of active subsidies? 2) Do insectivores with different mobilities and foraging behaviours respond differently to the flux of spatial subsidies and does this interact with environmental variables? I answered these questions across four empirical chapters. This thesis focused on a biome identified as both impacted by agricultural intensification and comprising important perennially flowing freshwater (on the world’s driest inhabited continent): Australia’s temperate zone. In chapter two, I demonstrate longitudinal trends in riparian vegetation clearance at our study streams and tested models relating to spatial subsidies and riparian spider responses. I conducted vegetation surveys and monitored in-stream temperature at six perennial streams that run through a riparian vegetation clearance gradient, and related these to abundances, biomass and community composition of riparian spiders and their prey (including emergent aquatic invertebrates). In chapter three, I focused on the orb-weaving spider species, Tetragnatha valida and compared the relative contributions of low flux, high quality aquatic prey and terrestrial prey to its diet at perennial streams using stable isotope analysis. In chapter four, I investigated the role of riparian vegetation structure and the abundance and biomass of emergent aquatic prey in explaining variation in the foraging activity and community composition of insectivorous bats that occupy perennial stream habitats. Finally, in chapter five I continuously monitored the activity of insectivorous bats at a survey reach to investigate potential concordance between foraging activity, moon illumination and heat accumulation by the stream. This thesis represents ‘another string in the bow’ of spatial subsidy research that focuses on biomes and taxa that are seldom studied. The literature identifies that active subsidies, including emergent aquatic invertebrates, must be studied in the context of donor and recipient ecosystem dynamics. Despite this, few studies thoroughly measure these dynamics. The present study bucks this trend and extensively surveys relevant ecosystem characteristics including in-stream temperature and vegetation structure, and in-so-doing provides valuable context which underpins diverse riparian insectivore responses to the flux of spatial subsidies. By contrasting different modes of insectivory, this thesis provides new insight into the trophic dynamics of stream-riparian systems. Studies like these are important in a rapidly changing world.

Riparian vegetation is essential for headwater streams, as it regulates allochthonous inputs of coarse particulate organic matter (CPOM) delivered into streams. CPOM accumulates in patches across the streambed, these patches are sources of energy and shelter where ecological linkages between aquatic populations occur. This group of studies evaluate such relationships in Hughes Creek, Victoria, southern Australia. The first of these studies evaluates the evidence documented in 45 studies which were undertaken mostly in temperate or subtropical regions of the U.S.A., Canada, Spain and Australia. The main focus of these works was to evaluate the effect of deforestation upon allochthonous inputs of CPOM, often in first and second order streams. Most studies addressed airborne inputs only, while lateral surface inputs, or downstream transport of CPOM were not commonly studied. Hedges’ effect size (g) was calculated for allochthonous inputs data from the 45 articles and plotted against deforestation. A threshold for airborne inputs and benthic organic matter (BOM) standing stock was observed when deforestation reached 70%. At that level of deforestation, effect sizes decreased by up to -5 standard deviations. The second study encompassed a field survey where forested and low forested sites along the one stream were evaluated. The survey required the collection of allochthonous inputs monthly for one year, where airborne, lateral surface transfer (LST), and drifting CPOM fractions were collected in sites with contrasting forest cover. Sites with intact vegetation showed high inputs (14 kg m-2 DW year-1), while deforested reaches showed lower airborne inputs (9.25 kg m-2 DW year-1). LST inputs represented 42% of allochthonous inputs in forested reaches, and 37.5% in deforested sites. The transport of CPOM downstream was similar between forested and deforested sites (23-25 kg DW year-1). Given this similarity in CPOM transportation, and that the majority of streams in Victoria are deforested, patches of riparian forest might be an attractive management option for restoration/management of streams. However, it is necessary to be mindful of the scope and limitations of forested patches along streams, as they might not provide resources to neighbouring areas. Rather, forested sections tend to retain most of their allochthonous inputs within their boundaries. The third study of this thesis comprises a field survey where patches of CPOM, located on the streambed of forested and deforested reaches, were collected in Summer, Spring and Winter. CPOM was separated intro fractions of leaves, bark and twigs. It was found that the type of cover did not modify the mass of CPOM fractions between forested and deforested reaches (p > 0.05). However, the results show significant differences between Sites within Forest Cover for all fractions, with exception of leaf material. The dominant patterns suggest high variation between sites and shifts between seasons. In relation to the contribution of each fraction provided to CPOM benthic standing stock, it was found that during the three sampling seasons, benthic CPOM composition was dominated by, in decreasing order, twigs, bark, leaf, and grass. Additionally, macroinvertebrates found in CPOM patches were separated and sorted into genus and species when possible. The analysis of species densities between forested and deforested sites show that Simulium ornatipes and Ecnomina F sp. densities differed between the two types of forest cover, while the remaining species showed no differences. However, Simulium ornatipes showed strong differences between sites. Ecnomina F sp. was the only taxon to show a significant difference related to forest cover, without having a substantial difference between sites within the same forest cover. On the other hand, Ecnomus continentalis, Notalina sp., Chemautopsyche sp, Hydroptila, Berosus (larvae), and Micronecta sp. showed higher significant differences in summer; whereas Chemautopsyche sp. and Hydroptila sp. densities were minimal in patches during spring. The regressions between the mass of CPOM and density of species showed that some presented negative relationships between specimens’ density and the increase of CPOM mass, as illustrated by Ecnomia F sp., Cheumatopsyche sp., and Nousia sp. The last study of this thesis was a field experiment where the size and spatial distribution of CPOM patches was manipulated, due to small-scale fragmentation being predicted to affect species densities, particularly where patches are ephemeral or organisms are transported advectively. CPOM patches were deployed in two possible configurations (a) one big patch treatment (BPT), comprised of 12 smaller sub-patches of the same size, and (b) 12 split patches (SPT), which were distributed across the streambed. Patches from the split treatment were of two sizes, double (300 cm2) and single (150 cm2). BPT and SPT patches from both treatments were oriented randomly on the stream (parallel or perpendicular) with respect to water flow. After 10 days, samples were collected of 13 common macroinvertebrates which had colonised the patches. It was found that the genera Offadens spp. and Notriolus spp. had responded to the orientation of patches in both treatments. Moreover, in SPT sites Offadens spp., Cheumatopsyche spp., and Notriolus spp. showed significantly higher densities in small patches, suggesting that species densities, which show no searching strategies for resources, are likely to be affected by patch size. The knowledge generated in this thesis provides a greater understanding of the effect upon macroinvertebrates densities by deforestation of a creek that flows through agricultural lands in southern Australian.

Ocean acidification is increasingly recognized as a potentially devastating threat to marine ecosystems and the goods and services they provide. Despite this, no existing multilateral environmental agreement (MEA) explicitly requires a response to it and the issue remains largely unaddressed in international environmental law and policy. Many scholars and practitioners have sought to address ocean acidification under existing agreements, largely via proposals for treaty amendments or the conclusion of new legal instruments such as implementing agreements or protocols. Implementation of these proposals has been limited. The thesis takes an interdisciplinary approach to exploring the possible MEA governance of ocean acidification. This is done by analysing existing treaty texts through alternative problem frames (treaty interpretation) and comparing their capacity to respond to ocean acidification against an idealized version of ocean acidification governance (gap-analysis). This thesis contends that the current framing of ocean acidification as a CO2 problem concurrent to climate change has resulted in the problem being regarded as predominantly outside the mandates of most MEAs, thereby narrowing the scope of responses available and creating significant gaps in the global governance architecture for ocean acidification. It argues that the utilization of alternative problem frames can situate the issue more effectively within existing MEA mandates, thereby opening up response options without the need for the development of new legal instruments.

Drownings on hazardous rocky coasts are a global problem but are an especially acute issue in Australia where they account for 19% of all coastal drownings. The risk of drowning while fishing from rocky coasts is primarily understood as an outcome of overtopping waves sweeping ‘rock fishers’ off rocky platforms and into the sea, with associated solutions focusing primarily on raising awareness of this risk. Few studies have explored how rock fishers perceive risk, nor how their length of experience influences their behaviour. This thesis explores the different ways that rock fishers perceive risk as well as how closely ‘experiential-experts’ perceptions align with rock fishing-related drowning incidents in the National Coronial Information System (NCIS). Experienced fishers are considered noncertified experiential-experts, whose repeated first-hand experience with risk informs their ‘expert’ perceptions. An innovative mixed methodology integrating qualitative GIS methods was used to address five key areas: First, exploring the spatial and temporal processes that differentiate risk perceptions of experienced from inexperienced rock fishers is done by conceptualising risk as relational. Second, the different ways fishers move through and map hazardous space is explored. Overlaying fishers’ GPS movement with sketch maps is used to visualise how fishers with different lengths of experience navigate and represent their everyday practices in hazardous space. Third, experiential-experts’ perceptions of ‘freak waves’ are compared to rock fishing-related drowning incidents in the NCIS. Fourth, experiential-experts’ perceptions of how fishers enter the sea and drown are compared to how drownings are reported in the NCIS. Lastly, fishers’ collective risk management practices are discussed with reference to the predominant framing of risk as an individualized phenomenon. Results suggest that years of experience in hazardous coastal environments helps fishers become more capable of anticipating and reacting to hazardous situations ‘safely’ because they are more attuned to how changing conditions affect risk. This includes experiential-experts’ attunement to where, how, and why risk will emerge in different spaces, depending on the daily interrelationships between coastal conditions. Attunement to how these interrelations affect site-specific hazards was also used to challenge common myths (e.g. freak waves) perpetuated by the media and in government signage. This draws attention to the spatial and temporal phenomenon that drives risk perceptions as well as the implications for future perception-oriented research that adopts a relational understanding. By adopting a relational understanding of risk, this thesis also opens new possibilities for understanding human-environment systems, which typically overlook how, where, and for how long risky human-environment interactions are perceived in space, if at all. The results may inform coastal risk managers as they consider experiential-experts' perceptions of the human-environment interactions that produce risk and the relational ways in which people anticipate and react to risk while undertaking hazardous activities.

Within new configurations of the ‘Great Australian Dream’, high-rise living in Australian cities has become not only an acceptable housing configuration for the middle classes but also a desirable one. Enquiring deeply into the tactics and strategies that building inhabitants use to live vertically in the city, this thesis explores the ways in which the design, inhabitation, and maintenance of middle-class high-rise developments are negotiated in Melbourne inner-suburbs. It explores dwellers’ agency in the negotiation of design choices and co-production of high-rise spaces, using mixed qualitative methods combining walking tours and semi-directed interviews. Drawing on the new geography of architecture and on a relational approach to housing and home, the research engages with a theory of practice acknowledging tactical and strategic actions in the city. It argues that dwellers reshape the socio-material configurations and spatial relations of apartment living set by designers, developers and housing technologists. Explicitly recognising of the role of social class in high-rise living, the research suggests that apartment developments are highly contested sites where intended lifestyles and aspirations are negotiated by varied institutions and actors, through a distinctive set of temporal and spatial actions. It finds that competing actors all work towards the co-production of high-rise living spaces and cultures. However, the thesis also shows that housing relations in the practice of middle-class apartment living outline an uneven and changing distribution of power between those who develop strategies and those who craft tactics. More broadly, this research opens up a deeper understanding of how this new kind of vertical city reflects and transforms configurations of status, power and identity in the Australian suburb.