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Aim Changing preferences regarding which species humans have transported to new regions can have major consequences for the potential distribution of alien taxa, but the mechanisms shaping these patterns are poorly understood. We assessed the extent to which changes in human preferences for transporting and introducing alien freshwater fishes have altered their biogeography. Location Australia. Methods We compiled an up‐to‐date database of alien freshwater fishes established in drainages in Australia before and after the number of established alien fish species doubled (pre‐1970 and post‐1970, respectively). Using metacommunity models, we analysed the influence of species traits and drainage features on the distribution of alien fishes that established pre‐ and post‐1970. Results Alien fishes in Australia were introduced via four main transport pathways: acclimatization, aquaculture, biocontrol and ornamental trade. The relative importance of each pathway changed substantially between the two periods, accompanied by changes in the distribution of alien fishes and the variables predicting their distribution. Pre‐1970, most species (64%) were introduced by acclimatization societies for purposes such as angling and biocontrol, and these fish have established in inland drainages more heavily impacted by human activities. In contrast, most of the post‐1970 introductions (69%) were ornamental fishes, with most species established in small, north‐eastern, tropical and subtropical coastal drainages. Main conclusions Substantial changes in introduction preferences and transport pathways over time have altered both the patterns and underlying processes shaping the biogeography of alien fishes in Australia. Our findings highlight the need for caution when using historical data to infer potential future distributions of alien species. The continuing spread of alien species means traditional biogeographical units may no longer be identifiable in the foreseeable future.

Arid landscapes are highly water-limited environments and all water (surface and groundwater) is environmentally, culturally and economically important. Springs, sites where groundwater discharges at the Earth's surface, are often the only perennial aquatic environments in arid regions. By providing habitats for aquatic biota, as well being an essential water resource for terrestrial species and human settlements, they are small natural features that make a contribution to ecological processes and biodiversity that extends far beyond their area. Many contain endemic, rare or relictual species of plants, fishes and invertebrates and are recognized as globally important biodiversity hotspots and evolutionary and ecological refugia. However, water resource development and invasive species are major threats to these systems. Future climate scenarios indicate that extended droughts may become more common in some arid regions. Such droughts will increase the pressure to extract groundwater for human uses. Increasing aquifer drawdown will result in the loss of some spring habitats and the endemic and dispersal-limited species they support. Conservation challenges include addressing the additive impacts of water extraction and exotic and invasive species and managing recreational activities. Although the isolation and small size of arid land springs makes them extremely vulnerable to anthropogenic impacts, it also means that protection and management may be more feasible and cost effective than for larger aquatic ecosystems. However, multiple approaches and ongoing actions will be required to address additive impacts. Examples of current conservation measures include fencing to exclude feral herbivores, removal of alien aquatic species and assisted re-colonisation of dispersal-limited, endemic species. The fundamental conservation priority is the protection of the groundwater resource (aquifers) on which arid land springs depend.

Artesian springs are particularly sensitive freshwater ecosystems, characterized by specialized flora and fauna which, owing to their isolation, are often endemic. Thus, protection of spring habitats and endemic spring biota is important for biodiversity conservation, particularly because human impacts such as invasive species, habitat destruction, and fragmentation can have such devastating effects. This study investigated the mitochondrial DNA (mtDNA) genetic diversity and structure of two critically endangered (IUCN) freshwater fish species: red-finned blue-eye Scaturiginichthys vermeilipinnis, and Edgbaston goby Chlamydogobius squamigenus, with the aim of assisting management agencies to establish relocated populations that conserve the genetic integrity and evolutionary potential of both species. 2862 bp from multiple mtDNA genes were amplified from 111 red-finned blue-eye individuals (17 from the 1990s and 94 from 2010), and a 660 bp segment of mtDNA cytochrome b was amplified from 111 Edgbaston goby individuals (from 2010). In total, 14 concatenated mtDNA haplotypes were identified in red-finned blue-eye and three cytb haplotypes were identified in Edgbaston goby. Overall assessment of the genetic diversity and structure of the endemic fish fauna from the Edgbaston springs revealed low levels of diversity in both species and a loss of haplotypes in red-finned blue-eye over time. In addition, both species displayed significant genetic structure: at the spring scale for red-finned blue-eye and at the spring group scale for Edgbaston goby. It is concluded that without the appropriate management of relocated populations, such as considering genetic structure and diversity and selecting high quality habitats, these species are at a severe risk of losing evolutionary potential and becoming extinct. This study provides a valuable example for conservation managers of the contribution that population genetic studies can make regarding the adaptive management of endangered species. Copyright © 2016 John Wiley & Sons, Ltd.

Flagship species, especially mammals and birds, are commonly used to increase awareness of conservation issues in marine and terrestrial ecosystems. However, flagship species oriented programs are often ad hoc with initiatives scarce in the freshwater context. Here, we aim to identify potential flagship candidates that would appeal to a broad cross section of society at a continental scale where freshwater ecosystems are under threat from human impacts. We identified 19 species from a list of 299 Australian freshwater fishes on the basis of body size, trophic guild and threatened species status assuming these characteristics of flagship species are transferable from previous work on terrestrial flagship species. We considered the potential of species to be of international appeal but focused mostly on eight relevant interest groups within Australia. This followed the rationale that public engagement with conservation issues in freshwater systems might be more effective if the link between fish species and the decisions people make were better understood, and we acknowledge the diverging interests of stakeholders. This scoping work contributes towards addressing the challenges of connecting societies to the principles of sharing water resources with ecosystems, and represents the first continental-scale assessment of its kind.

Summary A species recovery project for the endangered fish Red-finned Blue-eye (Scaturiginichthys vermeilipinnis) commenced in 2009 at Edgbaston Reserve in central western Queensland. To date, the project has included relocations and control of alien Eastern Gambusia (henceforth Gambusia, Gambusia holbrooki), using the piscicide rotenone. Preventing Gambusia colonising springs where Red-finned Blue-eye occur or have been relocated is crucial to the success of the project. As such, this study tested the use of porous silt fences that were installed around five springs from 2012. Results indicate that silt fencing is a suitable barrier material and that provided installed silt fences are serviced regularly, the material is an effective method of quarantining populations of endangered species in isolated aquatic environments. Four of the five installed fences were effective, and maintenance consisted of small repairs at regular intervals (quarterly) followed by replacement after 2 years. As such, silt fencing may have wider application in the conservation of endangered fish and other organisms, particularly in areas where isolated waterbodies occur and where their size renders exclusion fencing a practical recovery action.

The endorheic Lake Eyre Basin drains 1.2 million square kilometres of arid central Australia, yet provides habitat for only 30 species of freshwater fish due to the scarcity of water and extreme climate. The majority are hardy riverine species that are adapted to the unpredictable flow regimes, and capable of massive population booms following heavy rainfall and the restoration of connectivity between isolated waterholes. The remainder are endemic specialists from isolated springs with very restricted ranges, and many are listed under relevant state and national endangered species legislation and also by the International Union for Conservation of Nature (IUCN). For these spring communities, which are sustained by water from the Great Artesian Basin, survival is contingent on suitable habitat persisting alongside extractive mining, agriculture and the imposition of alien species. For the riverine species, which frequently undertake long migrations into ephemeral systems, preservation of the natural flow regime is paramount, as this reinstates riverine connectivity. In this study, fish were sampled from the Bulloo River in the east to the Mulligan River in the west, along a temporal timeframe and using a standard set of sampling gears. Fish presence was influenced by factors such as natural catchment divides, sampling time, ephemerality and the occurrence of connection flows and flooding. Despite the comparatively low diversity of species, the aquatic systems of this isolated region remain in good ecological condition, and as such they offer excellent opportunities to investigate the ecology of arid water systems. However, the presence of both endangered species (in the springs) and invasive and translocated species more widely indicates that active protection and management of this unique area is essential to maintain biodiversity and ecosystem integrity.

Arid zone catchments experience extreme hydrological variability and some rivers are entirely ephemeral, replenished only by intermittent flooding. The ecological roles of ephemeral systems are rarely studied. This paper describes movement patterns of fish in the Mulligan River, an ephemeral system in the Lake Eyre Basin, central Australia. Several sites were sampled along a temporal gradient encompassing floods and dry periods. After a single major flood in 2007 up to seven fish species were found at sites up to 300 km from the closest permanent waterhole. Following a series of floods (when waterholes were replenished and remained wet between 2009 and 2011) a further five species were recorded including the first records for the Lake Eyre hardyhead, Craterocephalus eyresii, from the rivers of far western Queensland. The presence of all species known from the parent catchment (the Georgina, where permanent waterholes occur) in the ephemeral catchment (the Mulligan) suggests that many fish species present in the river systems of central Australia are capable of dispersing long distances following the opening of movement pathways during flooding. However, two distinct groups of species were identified: extreme dispersing species, that move as far as possible into intermittently wetted habitats, and conservative dispersing species, that do not move as far, tending to inhabit deeper waterholes within mid-reaches of the river that are more likely to hold water for longer. Preservation of the natural flow regime of Australia's arid-zone rivers is important for maintaining these fish communities and facilitating study of their adaptations to ephemerality.

Despite their often temporary nature, intermittent rivers and ephemeral streams (IRES) provide important habitat, resource advantages, and nurseries for a range of fish species throughout the world. Fishes have adapted to the variable nature of these environments. A small subset of species using IRES has evolved specific traits such as air-breathing that make living in extreme habitats possible, but the majority relies on opportunistic dispersal to colonize such areas. Fish existence in IRES is precarious but when conditions are favorable, fishes play major roles in ecosystem functioning (e.g., trophic links in food webs). Habitat fragmentation of IRES by water extraction, river regulation, and climate change is the biggest threat to their ecological integrity and has major implications for the distribution and abundance of fishes in IRES.

Long-lasting surface water in arid-lands provide oases for aquatic biota, but their values as biological refugia have rarely been assessed. This study identified and mapped permanent natural wetlands across the Eastern Lake Eyre Basin in Australia and classified them into four types: riverine waterholes, rockholes, discharge springs and outcrop springs. Waterholes are the most widespread and numerous source of lasting water, while springs and rockholes are confined to relatively discrete clusters. The characteristics of each wetland type are summarised, and their biological values compared by examining various scales of endemism for vascular plant, fish and mollusc species. Discharge springs contain an exceptional concentration of endemic species across all three lifeforms at a range of scales. Waterholes are critical drought refugia for native fish species that also utilise a vast network of ephemeral streams during and after floods. Rockholes and outcrop springs do not contain any known specialised endemics, although the latter have disjunct populations of some plants and fish. The existing knowledge of antiquity, connectivity and habitat differentiation of the wetland types is compiled and their role in determining biological endemism is discussed. Exotic fish are a major conservation issue, the recovery of the discharge springs should be paramount, and the intact network of permanent waterholes should be preserved. A focus on endemism, combined with an understanding of the biogeographical processes underlying the observed patterns provides an effective and systematic approach to setting priorities for regional biodiversity conservation.

Managing competing endangered and invasive species in spatially structured environments is challenging because it is often difficult to control invasive species without negatively impacting the endangered species. Effective management action requires an understanding of the factors affecting the presence and absence of each species so that promising sites for relocation of endangered species combined with eradication of invasive species can be identified. We investigate competing hypotheses about the factors affecting occupancy of the critically endangered red-finned blue-eye (Scaturiginichthys vermeilipinnis; hereafter ‘RFBE'), a native Australian fish with a global distribution that is restricted to a group of shallow artesian springs. RFBE are threatened by competition with invasive mosquito fish (Gambusia holbrooki), which are steadily colonizing the springs, resulting in local extinctions of RFBE in most cases. While hypotheses about the influences of Gambusia on RFBE exist, none have been tested wit...

The red-finned blue-eye is the only pseudomugilid fish known from inland Australia and it is found only within an isolated cluster of Great Artesian Basin springs on Edgbaston Reserve in central-western Queensland. Surveys conducted in early 2009 revealed that red-finned blue-eye was present in four individual springs and that invasion of the spring complex by alien eastern gambusia was the most likely factor contributing to local extirpations. A three-year project commenced in the same year, with the twin aims of investigating methods for removing gambusia from springs and relocating small populations of red-finned blue-eye to fish-free springs. Gambusia removal with rotenone has been successful in a trial spring at Edgbaston and aquatic invertebrates have not been adversely affected. From a total of seven relocation events conducted in the same period, red-finned blue-eye populations have persisted in three. The results indicate that gambusia removal and red-finned blue-eye relocation are both suitable methods for red-finned blue-eye conservation, and as the fish is both endangered and declining, these methods and other strategies such as captive breeding should be implemented to prevent species extinction.

Freshwater environments and their fishes are particularly vulnerable to climate change because the persistence and quality of aquatic habitat depend heavily on climatic and hydrologic regimes. In Australia, projections indicate that the rate and magnitude of climate change will vary across the continent. We review the likely effects of these changes on Australian freshwater fishes across geographic regions encompassing a diversity of habitats and climatic variability. Commonalities in the predicted implications of climate change on fish included habitat loss and fragmentation, surpassing of physiological tolerances and spread of alien species. Existing anthropogenic stressors in more developed regions are likely to compound these impacts because of the already reduced resilience of fish assemblages. Many Australian freshwater fish species are adapted to variable or unpredictable flow conditions and, in some cases, this evolutionary history may confer resistance or resilience to the impacts of climate change. However, the rate and magnitude of projected change will outpace the adaptive capacities of many species. Climate change therefore seriously threatens the persistence of many of Australia’s freshwater fish species, especially of those with limited ranges or specific habitat requirements, or of those that are already occurring close to physiological tolerance limits. Human responses to climate change should be proactive and focus on maintaining population resilience through the protection of habitat, mitigation of current anthropogenic stressors, adequate planning and provisioning of environmental flows and the consideration of more interventionist options such as managed translocations.

Fish living in highly variable and unpredictable environments need to possess life-history strategies that enablethemtosurviveenvironmentalextremessuchasfloodsanddrought.Weusedthelength-frequencydistributionsof multiple fish species in multiple seasons and highly variable hydrological conditions to infer antecedent breeding behaviourinriversoffar-westernQueensland,Australia.Hypothesestestedwereasfollows:(1)recruitmentofsomeorall speciesoffishwouldoccurwithinwaterholesduringno-flowperiods;(2)therewouldbeseasonalrecruitmentresponsesin some fish species; (3) recruitment of some species would be enhanced by channel flows and/or flooding. Hydrology and the incidence of flooding were highly variable across the study area during 2006-2008. Flood-influenced recruitment was evident for Hyrtl's tandan, Barcoo grunter and Welch's grunter. Silver tandan, golden goby, Cooper Creek catfish and Australian smelt showed evidence of seasonal recruitment unrelated to antecedent hydrology. However, most species demonstrated continual recruitment in isolated waterholes, irrespective of antecedent flow conditions and season. Continual and seasonal recruitment capabilities have obvious advantages over flood-pulse recruitment in rivers with highly unpredictable flood regimes and underpin the persistence of many fish species in arid and semiarid rivers. Additional keywords: ephemeral rivers, fish life-history variation, flood pulse concept, Lake Eyre Basin, no-flow recruitment hypothesis.