Conservation Of Freshwater Biodiversity Research Articles

Cymbella tridentina sp. nov. (Bacillariophyta), a crenophilous diatom from carbonate springs of the Alps

A new benthic freshwater diatom, Cymbella tridentina sp. nov., was identified with the aid of light and scanning electron micrographs. The most characteristic morphological features are the valve outline (in particular, the shape of the ventral margin), the number of stigmata, and the length/breadth ratio. The new species was epilithic in carbonate, mountain, flowing springs in 3 Natural Parks of the Alps. The environmental preferences of the new species, assessed by the comparative analysis of the sites where it was found and by seasonal and longitudinal-distribution data available for the type locality, are quite distinctive. The new species appears to be rheophilic and oligotraphentic (not present in N-enriched sites), characteristic of dolomite mountain ranges (even if dolomite is not the dominating carbonate rock in the basin), and to develop year-round with low relative abundances (peaks associated with high discharge in autumn and spring). The combination of these ecological requirements might determine the preferential occurrence of C. tridentina sp. nov. in close-to-pristine, carbonate, mountain, flowing springs. The preference of the new species for the spring zone of running waters, and its possible use as an integrity indicator, is discussed in the wider context of crenobiosis. The importance of oligotrophic headwaters for the integrity of running-water systems and for the conservation of freshwater biodiversity, is highlighted.

Coexistence of Fisheries with River Dolphin Conservation

Freshwater biodiversity conservation is generally perceived to conflict with human use and extraction (e.g., fisheries). Overexploited fisheries upset the balance between local economic needs and endangered species' conservation. We investigated resource competition between fisheries and Ganges river dolphins (Platanista gangetica gangetica) in a human-dominated river system in India to assess the potential for their coexistence. We surveyed a 65-km stretch of the lower Ganga River to assess habitat use by dolphins (encounter rates) and fishing activity (habitat preferences of fishers, intensity of net and boat use). Dolphin abundance in the main channel increased from 179 (SE 7) (mid dry season) to 270 (SE 8) (peak dry season), probably as a result of immigration from upstream tributaries. Dolphins preferred river channels with muddy, rocky substrates, and deep midchannel waters. These areas overlapped considerably with fishing areas. Sites with 2-6 boats/km (moderately fished) were more preferred by dolphins than sites with 8-55 boats/km (heavily fished). Estimated spatial (85%) and prey-resource overlap (75%) between fisheries and dolphins (chiefly predators of small fish) suggests a high level of competition between the two groups. A decrease in abundance of larger fish, indicated by the fact that small fish comprised 74% of the total caught, may have intensified the present competition. Dolphins seem resilient to changes in fish community structure and may persist in overfished rivers. Regulated fishing in dolphin hotspots and maintenance of adequate dry season flows can sustain dolphins in tributaries and reduce competition in the main river. Fish-stock restoration and management, effective monitoring, curbing destructive fishing practices, secure tenure rights, and provision of alternative livelihoods for fishers may help reconcile conservation and local needs in overexploited river systems.

A heuristic approach to predicting water beetle diversity in temporary and fluctuating waters

An understanding of the causal mechanisms and processes that shape macroinvertebrate communities at a local scale has important implications for the management and conservation of freshwater biodiversity. Here we compare the performance of linear and non-linear statistics to explore diversity–environment relationships using data from 76 temporary and fluctuating ponds in two regions of southern England. We focus on aquatic beetle assemblages, which have been shown to be excellent surrogates of wider freshwater macroinvertebrate diversity. Ponds in the region contained a rich coleopteran fauna, totaling 68 species, which provided an excellent model system with which to compare the performance of two non-linear procedures (artificial neural networks—ANNs and generalised additive models—GAMs) and one more traditional linear approach (Multiple linear regression—MLR) to modelling diversity–environment relationships. Of all approaches employed, the best fit was obtained using an ANN model with only four input variables (conductivity, turbidity, magnesium concentration and depth). This model accounted for 82% of the observed variability in Shannon diversity index across ponds. In contrast, the best GAM and MLR models only explained 50% and 14% of this variation, respectively. Contribution profile analysis of conductivity, turbidity, magnesium concentration and depth, obtained from the best fit ANN through a hierarchical cluster analysis, allowed the identification of direct and proxy effects in relation to the environmental variables measured in this study. In each case, distinct clusters of ponds were identified in contribution profile analysis, suggesting that ponds across the two regions fall into a number of discrete groups, whose beetle faunas respond in subtly yet significantly different ways to key environmental variables. Aquatic coleopteran diversity in ponds in the two regions appears to be driven at a local scale by changes in relatively few physicochemical gradients, which are related to diversity in a clearly non-linear manner.

Freshwater biodiversity conservation: recent progress and future challenges

Freshwater habitats occupy ,1% of the Earth's surface, yet are hotspots that support ,10% of all known species, and ,M of vertebrate species. Fresh waters also are hotspots for human activities that have led to widespread habitat degradation, pollution, flow regulation and water extraction, fisheries overexploitation, and alien species introductions. These impacts have caused severe declines in the range and abundance of many freshwater species, so that they are now far more imperiled than their marine or terrestrial counterparts. Here, we review progress in conservation of freshwater biodiversity, with a focus on the period since 1986, and outline key challenges for the future. Driven by rising conservation concerns, freshwater ecologists have conducted a great deal of research over the past 25 y on the status, trends, autecology, and propagation of imperiled species, threats to these species, the consequences of biodiversity loss for ecosystem functioning, metapopulation dynamics, biodiversity hotspots, reserve design, habitat restoration, communication with stakeholders, and weaknesses of protective legislation. Nevertheless, existing efforts might be insufficient to stem the ongoing and coming multitude of freshwater extinctions. We briefly discuss 4 important challenges for freshwater conservation. First, climate change will imperil both freshwater species and human uses of fresh water, driving engineering responses that will further threaten the freshwater biota. We need to anticipate both ecological and human responses to climate change, and to encourage rational and deliberate planning of engineering responses to climate change before disasters strike. Second, because freshwater extinctions are already well underway, freshwater conservationists must be prepared to act now to prevent further losses, even if our knowledge is incomplete, and engage more effectively with other stakeholders. Third, we need to bridge the gap between freshwater ecology and conservation biology. Fourth, we suggest that scientific societies and scholarly journals concerned with limnology or freshwater sciences need to improve their historically poor record in publishing important papers and influencing practice in conservation ecology. Failure to meet these challenges will lead to the extinction or impoverishment of the very subjects of our research.

Assessing the conservation value of fresh waters: an international perspective

1. Introduction Philip J. Boon and Catherine M. Pringle 2. Background, philosophy and context Philip J. Boon and Catherine M. Pringle 3. Freshwater conservation in action: contrasting approaches in the US and UK Catherine Pringle and David Withrington 4. So much to do, so little time: identifying priorities for freshwater biodiversity conservation in the United States and Britain Jonathan Higgins and Catherine Duigan 5. Responding to environmental threats within the UK and North America Christopher A. Frissell and Colin W. Bean 6. Evaluating restoration potential T. E. L. Langford and C. A. Frissell 7. Methods for assessing the conservation value of rivers Philip J. Boon and Mary Freeman 8. Methods for assessing the conservation value of lakes Laurie Duker and Margaret Palmer 9. System aqua - a Swedish system for assessing nature conservation values of freshwaters Eva Willen 10. Evaluating Australian freshwaters for nature conservation Jon Nevill and Andrew Boulton 11. Evaluating freshwaters in South Africa Jay O'Keeffe and Christa Thirion 12. Evaluating freshwaters in developing countries Robin Abell and Mark Bryer 13. Conclusions Catherine M. Pringle and Philip J. Boon.

Pond conservation: from science to practice

In Europe, ponds are an exceptionally numerous and widely distributed landscape feature forming a major part of the continental freshwater resource and contributing significantly to freshwater biodiversity conservation. This has been reflected by a growing scientific concern over the first few years of the twenty-first century and is evidenced by an increasing number of academic publications on pond related topics, particularly those relating to biodiversity. It is essential, however, that this expanding scientific knowledge is widely disseminated to those involved with pond management and is then rapidly translated into action. Inevitably, the task of transferring science to practice remains a significant challenge. As a first step towards meeting this challenge the European Pond Conservation Network (EPCN), at its biennial meeting in 2008 in Valencia (Spain), made this the main theme of the conference together with two special workshops further encouraging exchanges between scientists, practitioners and policy makers. The papers selected for this special issue of Hydrobiologia (from over 120 communications presented) are all from the conference. They represent a diverse collection of themes from across the continent and North Africa and present new and original insights into topics as wide ranging as: pond biodiversity; human disturbance; landscape ecology; ecological assessment and monitoring; practical management measures; ecological restoration; hydrology and climate change; invasive species and threatened species. In all cases, the papers demonstrate an overriding need for the development of a tight link between scientific knowledge and management. Furthermore, scientific advances have to be beneficial for on the ground management and, vitally, have to be disseminated, communicated and implemented into local, national and international policy. As such, national and international networks (such as the EPCN) have a central role to play and have to develop a robust information and communication strategy which will enable the dissemination of best practice materials and advice across the continent and beyond. The work contained in this volume represents a step in the right direction and will help to ensure that ponds remain a characteristic and highly visible feature of the European landscape in the twenty-first century.

Imperiled crayfishes use hyporheic zone during seasonal drying of an intermittent stream

Despite the prevalence and importance of intermittent streams, few studies have examined their use by crayfishes. We documented persistence in an intermittent stream and use of the hyporheic zone by 2 imperiled crayfishes, Orconectes williamsi and Orconectes meeki meeki, upon stream drying. During 2005 to 2007, we monitored summer flows and crayfish densities in 10 riffles in a Missouri (US) Ozark stream to document stream drying and crayfish persistence. Stream drying variables were riffle wetted area (m2) and current velocity (m/s). Crayfish density estimates were obtained with a quadrat sampler. We sampled monthly (May–August 2006) to examine crayfish response to decreased flows, and excavated dry quadrat samples (to 30 cm depth) after surface flows ceased. Over 2 periods during summer 2007, we used baited traps in the stream and a downstream reservoir where the stream terminates to examine whether crayfish migrated from the stream to permanent water in response to drying. Riffles dried significantly by July, few had surface water present by August, and all were rewetted by the following June. Annual June densities of O. williamsi remained stable throughout the study, whereas densities of O. m. meeki were lower in 2007 than 2005. Both species burrowed to the hyporheic zone during drying, and crayfish densities were similar to those estimated in riffles before drying. We found no evidence that either species migrated to permanent water in the reservoir during drying. Use by crayfish of the hyporheic zone during drying and interannual persistence in intermittent streams suggests that hyporheic habitats are important for conservation of these crayfishes. Our study contributes to the increasing body of knowledge that indicates the importance of intermittent streams for conservation of freshwater biodiversity.

Note on a Highly Diverse Rotifer Assemblage (Rotifera: Monogononta) in a Laotian Rice Paddy and Adjacent Pond

AbstractDuring August 1999, the authors conducted a sampling campaign in the PDR Laos, in order to contribute to the chorology of rotifers in the region. Two samples, collected from a rice paddy and an adjacent pond near Vientiane, Laos, contained a total of 135 rotifer species including several that appear new to science or that warrant taxonomical or biogeographical comments. No new species can be named, but Cephalodella boettgeri Koste and Floscularia armata Segers are recorded for the second time ever after their description from South America, and Parencentrum lutetiae (Harring and Myers) and Polyarthra luminosa Kutikova are new to Southeast Asia. This raises the number of rotifers recorded from Laos from 9 to 130. The diversity recorded is remarkable, especially when compared with that of similar habitats in the Thai part of the floodplain of River Mekong and its tributaries. Different agricultural practices may account for the difference in species richness. Similar highly diverse rotifer faunas are known to occur in natural, tropical and subtropical floodplain systems only. This accords with the view that rice paddies can be regarded as artificial wetlands or floodplain systems, which, if managed taking biodiversity concerns into account, may have a potential for the conservation of freshwater biodiversity. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Effectiveness of protected area networks in representing freshwater biodiversity: the case of a Mediterranean river basin (south‐eastern Spain)

Abstract Biodiversity is probably at greater risk in freshwater systems than in other ecosystems. Although protected areas (PAs) play a vital role in the protection of biodiversity and are the mainstay of most conservation polices, the coverage of biodiversity by existing PA networks is often inadequate and few reserves are created that take into consideration freshwater biota. In this paper an attempt is made to address the performance of protected areas in the context of freshwater biodiversity conservation using data records for water beetles in a Mediterranean river basin. Although the present PAs in the study area cover a relatively high number of water beetle species, the distribution and extent of reserves is still inadequate or insufficient to protect freshwater biodiversity, especially species of conservation concern. Alternative area‐selection methods (hotspots and complementary) were more efficient than PAs for representing water beetles. Within these, complementarity was the most efficient approach, and was able to represent all species in a significantly lower area than the current PA network. On the other hand, the future Natura 2000 Network will result in a great increase in the total area of protected land as well as in the biodiversity represented. Unfortunately, the occurrence of a species within a protected area is not a guarantee of long‐term survival because the extent of PAs is often insufficient and disturbances occur outside park boundaries. Thus, whole‐catchment management and natural‐flow maintenance are indispensable strategies for freshwater biodiversity conservation. Copyright © 2006 John Wiley & Sons, Ltd.

Freshwater biodiversity: importance, threats, status and conservation challenges

Freshwater biodiversity is the over-riding conservation priority during the International Decade for Action - 'Water for Life' - 2005 to 2015. Fresh water makes up only 0.01% of the World's water and approximately 0.8% of the Earth's surface, yet this tiny fraction of global water supports at least 100000 species out of approximately 1.8 million - almost 6% of all described species. Inland waters and freshwater biodiversity constitute a valuable natural resource, in economic, cultural, aesthetic, scientific and educational terms. Their conservation and management are critical to the interests of all humans, nations and governments. Yet this precious heritage is in crisis. Fresh waters are experiencing declines in biodiversity far greater than those in the most affected terrestrial ecosystems, and if trends in human demands for water remain unaltered and species losses continue at current rates, the opportunity to conserve much of the remaining biodiversity in fresh water will vanish before the 'Water for Life' decade ends in 2015. Why is this so, and what is being done about it? This article explores the special features of freshwater habitats and the biodiversity they support that makes them especially vulnerable to human activities. We document threats to global freshwater biodiversity under five headings: overexploitation; water pollution; flow modification; destruction or degradation of habitat; and invasion by exotic species. Their combined and interacting influences have resulted in population declines and range reduction of freshwater biodiversity worldwide. Conservation of biodiversity is complicated by the landscape position of rivers and wetlands as 'receivers' of land-use effluents, and the problems posed by endemism and thus non-substitutability. In addition, in many parts of the world, fresh water is subject to severe competition among multiple human stakeholders. Protection of freshwater biodiversity is perhaps the ultimate conservation challenge because it is influenced by the upstream drainage network, the surrounding land, the riparian zone, and - in the case of migrating aquatic fauna - downstream reaches. Such prerequisites are hardly ever met. Immediate action is needed where opportunities exist to set aside intact lake and river ecosystems within large protected areas. For most of the global land surface, trade-offs between conservation of freshwater biodiversity and human use of ecosystem goods and services are necessary. We advocate continuing attempts to check species loss but, in many situations, urge adoption of a compromise position of management for biodiversity conservation, ecosystem functioning and resilience, and human livelihoods in order to provide a viable long-term basis for freshwater conservation. Recognition of this need will require adoption of a new paradigm for biodiversity protection and freshwater ecosystem management - one that has been appropriately termed 'reconciliation ecology'.

Exotic species, fisheries and conservation of freshwater biodiversity in tropical Asia: the case of the Sepik River, Papua New Guinea

1. Development of effective conservation strategies for freshwater biodiversity must take account of the trade-off between species preservation and human use of ecosystem goods and services. The latter cannot be prevented, and attempts to manage ecosystems that focus solely on maximizing biodiversity will fail. 2. A compromise position of management for ecosystem functioning and human livelihoods — rather than preservation of every species — will provide a better basis for biodiversity conservation. This has implications for the management of exotic species. 3. There are some situations, in lentic habitats in Sri Lanka, for example, where the establishment of exotics has increased fishery yields without apparent detriment to native biodiversity. The Sepik River in Papua New Guinea provides another illustration of potential compromises between human livelihoods and biodiversity conservation. 4. The Sepik supports a relatively unproductive fishery. Two fish stocking projects (in 1987–93 and 1993–97), representing a partnership between the Papua New Guinea Government and the United Nations (UNDP/FAO), led to the introduction of a suite of exotic fish into the Sepik. Species were selected on the basis of their potential to occupy niches not filled by native fish. Unfortunately, the outcomes of these introductions are poorly documented, although there is preliminary evidence both of increased human use of exotic fish as well as declines of some native species associated with the spread of exotics. 5. Better understanding of the results of the Sepik fish introductions is important, because the pressures of burgeoning human populations in most of tropical Asia make it impossible to preserve near-pristine environments such as the Sepik. While attempts to conserve natural or near-natural systems must remain a priority, there is a need to develop strategies for the management of damaged or degraded ecosystems, which may contain exotics, with the aim of maintaining ecosystem functioning and, if possible, maximizing the persistence of native biodiversity. Copyright © 2006 John Wiley & Sons, Ltd.

Conservation of Freshwater Biodiversity: a Comparison of Different Area Selection Methods

The biodiversity of freshwater systems is endangered, especially in Mediterranean semiarid areas such as the south east of the Iberian Peninsula, whose rich and endemic biota is threatened by the development of surrounding land-crop irrigation. For this reason, the prioritization of areas for biodiversity conservation is an urgent target. In this study we used data records of water beetles from a province of the southeast of Spain for assessing priority areas for freshwater biodiversity conservation. We compare the performance of various area-selection methods, ranging from scoring procedures to complementarity-based algorithms, which are based on different criteria such as richness, rarity and vulnerability. The complementarity approaches were more efficient than methods using scoring or richness and rarity hotspots for representing conservation targets in a given number of areas and for identifying the minimum set of areas containing all species at least once. Within these, the richness-based algorithm was more efficient than rarity-based algorithm. Crucial target habitats for aquatic biodiversity conservation in the area studied are streams at medium altitude, hypersaline streams, and endorreic and karstic complexes.

Habitat use and dispersal of the invasive crayfish Procambarus clarkii in ephemeral water bodies of Portugal

We used radio-telemetry to analyze habitat use and dispersal of the invasive crayfish Procambarus clarkii in the extreme environmental conditions of a temporary river in southern Portugal. The rationale of this study was that an understanding of the properties that make this species a successful invader can be of help for the conservation of freshwater biodiversity. The results showed that: (1) crayfish displaced at a similar rate (ranging 2.5–38 m d−1) as other European populations; (2) movement was faster at night; (3) crayfish movement had no clear environmental correlates, except for water temperature; (4) peaks of more intense locomotion were intercalated with longer periods of slow or null speed; and (5) P. clarkii did not excavate burrows in the study habitat, but took refuge under boulders and most often occupied complex microhabitats (e.g., vegetated sections of the river). The conclusion was that, notwithstanding their extreme conditions, ephemeral water bodies in southern Europe are highly susceptible to invasion by P. clarkii.

Identifying important sites for conservation of freshwater biodiversity: extending the species‐based approach

Abstract Species richness in relation to area of habitat is extremely high in many freshwater groups, with an estimated 12 000 fish, 5000 amphibians and 2000 mollusc species dependent on freshwater habitats. Other major groups dependent upon fresh waters include, reptiles, insects, plants and mammals. The IUCN Redlist and The Nature Conservancy assessments both indicate the serious vulnerability and degradation of inland water habitats world‐wide. It is evident that there are neither the resources nor the time to protect all areas where species are under threat. Clearly a method is needed for prioritising inland water sites for conservation at both local and regional scales. IUCN held a workshop in June 2002 to develop a method for prioritising important inland water sites for biodiversity conservation. The goal of the workshop was to develop a method which would help to focus on conservation efforts and funds at the regional scale and would serve as a tool for active conservation efforts at the local scale. The method was developed on the foundations of a review of the existing site prioritisation schemes for terrestrial, marine and freshwater ecosystems. Expert representatives for a broad range of priority taxa and for existing schemes provided input to the development of the site prioritisation method. This paper describes the development of the method, the selection criteria adopted, guidelines for their use and the site selection procedure.

INVERTEBRATE BIODIVERSITY IN AGRICULTURAL AND URBAN HEADWATER STREAMS: IMPLICATIONS FOR CONSERVATION AND MANAGEMENT

The urbanization of agricultural lands is currently one of the dominant patterns of land use change in developed countries. In the United States and parts of Europe, this has led to the implementation of agricultural land preservation programs and riparian protection and replanting efforts along urban streams. The ecological benefits of such programs for the conservation of freshwater biodiversity have yet to be fully explored. We designed a study to investigate the patterns of stream macroinvertebrate community structure along a gradient of agriculture to urban development, and the patterns among urban streams that vary in the amount of intact riparian buffer. In 2001 and 2002, we sampled the 29 small headwater streams comprising the outlying tributaries of four watersheds just north of Washington, D.C., in Montgomery County, Maryland, USA. This region has had dramatic urban development over the last 50 years, yet significant efforts have been made to maintain riparian buffers and promote preservation of agricultural land.Macroinvertebrate richness was strongly related to land use, with agricultural streams exhibiting the highest macroinvertebrate diversity. Taxa richness was related negatively and linearly (no statistical threshold) to the amount of impervious surface cover. For the urban streams, there was a strong positive relationship between invertebrate diversity and riparian forest cover. Urban streams with high amounts of intact riparian forest exhibited biodiversity levels more comparable to less urban areas despite high amounts of impervious cover in their catchments. The agricultural headwater streams in this study were not only more diverse than the urban headwaters, but their levels of macroinvertebrate diversity were high compared to other published estimates for agricultural streams. These higher richness values may be due to widespread use of “best management practices” (BMPs), including no‐till farming and the implementation of woody and herbaceous riparian buffers, which may alleviate many acute stressors caused by cultivation. These findings suggest that, if managed properly, the preservation of agricultural land from development may help conserve stream invertebrate biodiversity, and that maintenance of riparian forests even in highly urbanized watersheds may help alleviate ecological disturbances that might otherwise limit macroinvertebrate survival.

Conservation of freshwater biodiversity: does the real world meet scientific dreams?

Conservation of freshwater biodiversity: does the real world meet scientific dreams?

The contribution of scientific information to the conservation and management of freshwater biodiversity in tropical Asia

Tropical Asia (i.e. the Oriental biogeographic region) is the most densely populated and degraded region on Earth with the highest deforestation rates in the tropics. Flow regulation is a significant threat to riverine biodiversity in the region, and its impacts are combined with overharvesting, pollution and other sources of habitat degradation. In addition to these immediate threats, the potential impacts of exotic species and climate change are difficult to predict. Uncertainty about impact effects arises also from the fact that knowledge of the rich freshwater biodiversity of tropical Asia is incomplete, and up-to-date national or regional inventories are lacking. In part, this reflects taxonomic constraints, and a limited representation of Asian science in the international limnological and conservation literature. A survey of recent (1992–2001) international journals dealing with freshwater ecology and limnology in general, on one hand, and conservation biology on the other, reveal that the representation of scientists based in tropical Asia was extremely low. Scientists from tropical Asia authored fewer than 2% of more than 4500 papers dealing with freshwater biology; 57% of them were published in Hydrobiologia. Less than 0.1% of freshwater biology papers dealt with the conservation of biodiversity in tropical Asian fresh waters. The representation of Asian freshwater science in the conservation biology literature was also poor; 0.6% of 1880 papers surveyed. Such limited dissemination of information reflects a variety of constraints (e.g. manpower, funding, language, and entrenched attitudes), arising from sources both within and outside the region. Even the data that are published are not effectively deployed toward conservation ends. Awareness of some of the more egregious examples of overharvesting (e.g. of river turtles) in the region has increased, but strategies for the protection of riverine biodiversity remain underdeveloped. Where legislation to protect water resources has been put in place, it has been directed towards enhancing human use of water — not biodiversity conservation — and enforcement is weak. Exceptionally, the Chinese government has produced national ‘Red Data Books’ for endangered freshwater vertebrates, and legislation aimed at protecting species at risk, particularly from overharvesting, are in place. Huge obstacles remain, especially in the management of rivers crossing international boundaries. The Mekong River Commission (MRC) provides an example of a model for an international drainage basin that has made significant progress in establishing appropriate structures and mechanisms for sustainable development in a challenging political landscape. Not all of the Mekong riparian states participate in the MRC, and this will be essential for sustainable management. However, even within national borders, local interests can override drainage-basin perspectives. In many places in Asia, preservation of near-pristine freshwater environments is not a realistic option. Sustaining human livelihoods is an over-riding concern, and recognition of this fact must be built in to biodiversity conservation efforts. This has special implications for the management of exotic species, as the example of fish introductions to the Sepik River in Papua New Guinea shows. Notwithstanding the various factors that constrain publication by scientists in tropical Asia, we must recognise that poor dissemination research results will have consequences for the long-term preservation of the habitats and biodiversity that we study. A change in research strategy that establishes priorities, recognises the inevitability of trade-offs, and includes greater emphasis on engagement and partnerships — as in the MRC — is mandated.

Indicator taxa for the conservation of pond invertebrate diversity

Abstract Ponds are a valuable resource for the conservation of freshwater biodiversity, but are often extremely numerous in a given area, making assessment of the conservation value of individual sites potentially time consuming. The use of indicator taxa, the species richness of which is representative of total site species richness, may provide one way to improve the efficiency of survey work. However, such indicators are poorly developed for freshwater systems. A data set was used describing the occurrence of macroinvertebrate taxa in ponds in Oxfordshire, UK, to assess the extent to which variation in the species richness of selected taxa most consistently represented variation in all other taxa. Coenagriidae (Odonata) and Limnephilidae (Trichoptera) reflected the variation in species richness of other taxa most consistently, with Coenagriidae showing the best overall performance as an indicator taxon. For both suggested indicator taxa, selection of sites based solely on the presence of at least one species of indicator would represent over 95% of all species recorded across all sites. Further investigation in different geographical regions is necessary to establish whether these relationships are consistent over a wider area. Copyright © 2003 John Wiley & Sons, Ltd.

Can conservation assessment criteria developed for terrestrial systems be applied to riverine systems?

Australia's aquatic ecosystems are of outstanding diversity and interest on a world scale. As one of the world's driest continents, its water resources are under growing pressure, yet there are no systematic conservation efforts. Any moves towards aquatic biodiversity conservation must be pursued within appropriate scientific, policy, and management contexts. A key starting point is the articulation of aquatic conservation values. Concepts and criteria for biodiversity conservation are well established in the conservation of terrestrial ecosystems in Australia. They are often framed within legislation or derived through policy and practice. If freshwater biodiversity is to be conserved, then conservation criteria and methods of assessment need be integrated with possible mechanisms for protection. So it is useful to examine whether the criteria and thresholds applied to terrestrial systems are valid and appropriate for freshwater ecosystems. Two key questions are discussed: are commonly applied conservation criteria appropriate and adequate for aquatic ecosystems? and, is it feasible to apply criteria used in terrestrial systems to aquatic systems? The discussion is informed by evidence from two perspectives: a survey of views of river scientists and managers, and analysis of field studies of river conservation assessments in Australia. The data suggest that while the basic concepts that define biodiversity value can be applied to aquatic systems, difficulties are apparent in applying and interpreting the thresholds and decision rules used for terrestrial systems. In addition, the survey of scientists and managers in Australia showed that landscape scale values and riverine functions should be incorporated in the assessment and protection of riverine systems. The analysis concludes that conservation of freshwater biodiversity in Australia needs to be founded upon national legislation and policies for biodiversity conservation alongside conservation of terrestrial systems. However, different approaches to defining and assessing biodiversity value of freshwater ecosystems will need to be explored and specified.

Challenges to the conservation of Australian freshwater biodiversity: An epilogue

Challenges to the conservation of Australian freshwater biodiversity: An epilogue