The status of the medicinal leech Hirudo medicinalis in Europe and especially in the British isles

In spite of reports to the contrary, an analysis of 206 recent records for the years 1952 to 1982 shows that the medicinal leech Hirudo medicinalis Linnaeus is still present at one or more localities in 23 European countries (Albania, Austria, Britain, Bulgaria, Czechoslovakia, Denmark, Finland, France, German Democratic Republic, German Federal Republic, Greece, Hungary, Italy, Luxembourg, Netherlands, Norway, Poland, Rumania, Spain, Sweden, Switzerland, USSR and Yugoslavia). Its status is uncertain in Belgium, Portugal and European Turkey. It has disappeared from some localities in Britain but has been recently recorded at several others. It never occurred naturally in Iceland. Ireland is the only European country in which it once occurred but is now absent.     

The conservation of British inland salt marshes

British inland salt marshes are restricted to small areas around brine springs and in the vicinity of salt works. They are poor in species compared with coastal marshes. Brine spring habitats have been destroyed by the salt industry and by urban development, and are now extremely rare. The salt industry, however, gives rise to soils contaminated by brine through spillage and by causing subsidence. Subsidence sites are more extensive than either spillage or brine spring sites and provide the major inland saline sites in Britain. Although recent in origin and colonised by few halophyte species, these areas are valuable for comparative ecological experimentation and are attractive to birds on migration. The conservation of the more important sites is discussed and attention is also drawn to the loss of brine spring habitats in other European countries.     

Mercury concentrations in freshwater fishes in New Jersey

A statewide screening study found fish Hg concentrations to be correlated with pH, with site-specific factors creating appreciable variation within pH classes. High Hg concentrations were found in the Pine Barrens and in some fish from lakes in the rest of the state.     

Conservation of freshwater fishes of Sri Lanka

Sri Lanka supports a diverse fauna of freshwater fishes, 24% of which are endemic. A survey of the island's streams indicated that a number of the endemic fishes are threatened with extinction and others are depleted due to the interaction of deforestation, urbanization, gem mining, pesticides, exploitation, water diversions, and introductions of exotic species. It is clear that these declines should be halted for ethical, economic, and ecological reasons. Methods proposed to reverse the declines include captive breeding, better watershed management, translocation, and regulation of fisheries, especially that for aquarium fishes. The depauperate Second Peneplain is proposed as a site for translocation of endangered species.     

Ship noise and cortisol secretion in European freshwater fishes

Underwater noise pollution is a growing problem in aquatic environments and as such may be a major source of stress for fish. In the present study, we addressed the effects of ship noise and continuous Gaussian noise on adrenal activity in three European freshwater species. Underwater ship noise recorded in the Danube River and two Austrian lakes was played back to fish at levels encountered in the field (153 dB re 1 μPa, 30 min). Post exposure cortisol secretion was compared with control situations. Cortisol was measured with enzyme immunoassay techniques (EIA, ng cortisol/l water/g fish) in extracted aquarium water with corrections for fish mass. In the first series, two hearing specialists, the common carp (Cyprinus carpio) and the gudgeon (Gobio gobio) and one hearing generalist, the European perch (Perca fluviatilis) were exposed to ship noise. The noise level was well above hearing thresholds in these species. In a second series, fish were exposed to continuous Gaussian noise at a similar level (156 dB) which is known to induce temporary hearing loss in hearing specialists. All three species responded with increased cortisol secretion when exposed to ship noise. Interestingly, no elevation was observed when fish were exposed to continuous Gaussian noise. Our results indicate that ship noise characterized by amplitude and frequency fluctuations, constitutes a potential stressor in contrast to continuous noise. Surprisingly, the data also demonstrate no apparent differences between species possessing excellent hearing abilities (hearing specialists) and species with poor hearing abilities like perch.     

Integrating freshwater and terrestrial priorities in conservation planning

The integration of freshwater and terrestrial biodiversity priorities in systematic conservation planning is a major challenge to conservation planners. Maintaining upstream–downstream connectivity and the influence of catchments on freshwater ecological integrity are some of the issues that make it difficult to reconcile terrestrial and freshwater conservation planning. As a result most conservation assessments are often biased towards terrestrial systems without adequate incorporation of freshwater biodiversity in determining priority areas for conservation. In this paper, we propose a protocol for integrating the assessment of freshwater and terrestrial priorities in conservation planning, based on a case study from Mpumalanga Province in South Africa. The approach involves the separate assessment of freshwater priority areas, and using the outcome to influence the selection of terrestrial priority areas. This allowed both freshwater and terrestrial biodiversity to be incorporated in conservation planning without compromising their unique requirements. To test the effectiveness of this approach, we assessed percentage overlap between freshwater and terrestrial priority areas, target achievement, and the area required to achieve targets. We then compared the outcome from the proposed approach with the separate assessments of freshwater and terrestrial biodiversity priorities, and when both systems are given an equal weighting in a single assessment. The results showed that there was a noticeable improvement in the overlap of priority areas for freshwater and terrestrial biodiversity from 23% to 47%. Target achievement for freshwater biodiversity improved by 10% when terrestrial assessment was based on freshwater priority areas as opposed to terrestrial systems being assessed alone. There was negligible increase in area required, whether there was integration of freshwater and terrestrial biodiversity or no integration. We conclude that the most efficient way to achieve integration in conservation planning is to preferentially select areas where freshwater and terrestrial biodiversity priorities overlap.     

Environmental change and its impact on the freshwater fishes of Iran

Factors affecting the distribution and abundance of freshwater fishes in Iran are described. These include climate, devegetation, irrigation, and natural water level fluctuations (termed pre-industrial) and such factors related to industrialisation and population increase as devegetation, water abstraction, fishing, pollution, and faunal introductions. Conservation schemes are outlined and commented on and a list of threatemed fishes is given.     

The distribution of three uncommon freshwater gastropods in the drainage ditches of British grazing marshes

Marshland drainage channels (=ditches) in the UK are relicts of a once extensive habitat whose management requires quantitative information on the ecology of marshland organisms. Three freshwater gastropods in the UK Red Data Book (RDB), Segmentina nitida, Anisus vorticulus and Valvata macrostoma, are particularly poorly known, and we examined their macro-distribution across 106 ditches on four grazing marshes in SE England. Distribution reflected natural water quality, vegetation and anthropogenic factors. S. nitida occupied shallow calcareous ditches with dense emergent vegetation while A. vorticulus occupied less calcareous ditches with high plant diversity. Ditches with V. macrostoma were dominated by floating plants and slightly elevated chloride. S. nitida and V. macrostoma were absent from otherwise suitable ditches that had elevated nitrate and nitrite indicating effects from eutrophication. Conservation of these three gastropods at the regional scale requires reductions in catchment fertiliser use and also the protection of enough sites to provide the required range of natural factors (e.g., Cl and Ca). At the marsh scale, we suggest that quasi-traditional and rotational ditch clearance can provide the vegetation dynamics and diverse ditch network to ensure suitable habitat for all three species. Better information is required about dispersal, about the effectiveness of reintroduction, and about the most sensitive methods of ditch management.     

Habitat conservation priorities in British and European woodlands

Five types of British woodland are particularly important for habitat conservation, namely; relicts of medieval wood-pasture management; ‘native’ pine and birch woods in the Scottish Highlands; some coppices on ancient woodland sites; woods on inaccessible sites; and woods with a long period of natural structural development. The case for these priorities rests on the concepts of non-recreatability and past-naturalness, which are discussed. Together these woods form no more than 20% of existing woodland. Comparison with woodlands and forestry practice in Czechoslovakia and France shows how much the definition of priorities depends on the particular climate, woodland history and current forestry practices of Britain. The same concepts can apply to other semi-natural habitats in some circumstances.     

A large-scale conservation perspective considering endemic fishes of the North American plains

Regions with unique habitats often harbor endemic taxa associated with temporally stable habitats. We identified such habitats that sustain endemic fishes in the plains of North America. We also summarized threats to their conservation and identified remnant habitats that still harbor endemic fishes (refuges) based on post-1989 surveys. Major springs, smaller, spring-fed streams, larger rivers, and euryhaline habitats were associated with a total of 49 endemics. Endemism was attributable to climatic refugia associated with each habitat type and dispersal limitation among major river drainages and springs. Forty-one endemic fishes (84%) were declining or extinct. Dewatering, habitat fragmentation, and habitat degradation were main causes of declines, often present together. Pollution and non-native species were also threats in many cases. Evidence for 53 existing refuges was found. We considered 34 refuges to be “high-quality” because they harbored three or more endemics. Twenty of these (those with available data) maintained consistent streamflow regimes for at least 50 years up to 2009. Case studies suggest high stream length, more natural flow regimes, and fewer direct human impacts are features of high-quality refuges, but extinction thresholds are unquantified and extinction debts of refuges are unknown. Limited information on past extinctions suggests drought, a natural feature of the plains, combines with other threats to eliminate remnant endemic populations. Long-term conservation planning requires identification, protection, and restoration of high-quality refuges to reduce extinction risk, especially during future drought periods. Planning should be integrated with regional water resource planning, given scarcity of water in the region.     

Importance of reservoirs for the conservation of freshwater molluscs in a tropical urban landscape

Freshwater species and ecosystems are gravely imperiled, particularly within urban landscapes of tropical Asia. In one of the region’s most urbanized landscapes (i.e., Singapore), we determined: (1) the importance of six different habitats (i.e., catchment reservoirs, estuarine reservoirs, forest streams, rural streams, ponds and monsoon canals) for conserving the diversity of freshwater molluscs; (2) key environmental factors (e.g., pH) affecting molluscan distribution; (3) important biogeographical determinants (e.g., area) of molluscan richness within each habitat; and (4) the habitat affinities of introduced species. High sampling saturation was achieved at most study habitats with minimal sampling effort, suggesting that the utilization of molluscs as bioindicators can expedite freshwater conservation initiatives. Estuarine reservoirs (6.0 ± 2.0) had the highest molluscan richness, vis-à-vis catchment reservoirs, forest streams, rural streams, ponds and monsoon canals (3.0 ± 1.5; 0; 3.3 ± 2.0; 1.8 ± 0.5 and 3.5 ± 0.5 respectively). Both reservoir types possessed species compositions distinct from other habitats and contained majority (76%) of the sampled species. Reservoirs therefore serve to conserve the bulk of local freshwater malacofauna, especially if they are maintained at near-neutral pH levels (i.e., ∼7.3) and contain large substrates (i.e., rocks). Area was the best predictor of molluscan richness across all habitats, implying that larger freshwater habitats require higher conservation priorities than smaller ones. Introduced (non-native) species (e.g., Pomacea canaliculata) had high affinities for reservoirs, which are in need of monitoring to curb population expansions. The interminable growth of human settlements urgently requires a reconciliatory approach, which includes the ecologically-sound design and management of modified habitats to complement reserves in sustaining native freshwater species.     

The status and conservation of the freshwater pearl mussel Margaritifera margaritifera Linn. in Great Britain

All available records of the occurrence of the freshwater pearl mussel Margaritifera margaritifera Linn. in Great Britain have been collected. Analysis of these records shows that there has been a recent decline in numbers of the species, which is especially marked in England and Wales. The causes of this decline are thought to be primarily pollution and overfishing in England and Wales, and overfishing in Scotland. Apparently even sparse populations remain fertile, but it is concluded that unless conservation measures can reduce overfishing, pearl mussels will become rare and endangered. It is suggested that the best conservation measures will be to restrict pearl fishing to licensed fishermen, perhaps using non-destructive fishing methods, and to prohibit the use of sub-aqua equipment.     

Endemism and evolutionary history in conflict over Madagascar’s freshwater conservation priorities

Regional-scale biodiversity indicators provide important criteria for the selection of protected areas in conservation, but their application is often hindered by a lack of taxonomic knowledge. Moreover, different indicators include different types of information, sometimes leading to divergent conservation priorities. Madagascar tops the world list of biodiversity hotspots and much conservation effort has been directed toward its threatened plants and vertebrates. In contrast, its highly diverse freshwater invertebrate fauna has received comparatively little conservation attention. We conducted an inventory of Malagasy adephagan water beetles (Coleoptera, Dytiscidae, Noteridae, Gyrinidae, Haliplidae) using a combined morphological and molecular approach. In total, 2043 beetles from 153 sites were sequenced for cytochrome oxidase subunit I (cox1), and species delimitation was carried out using the coalescent-based GMYC model. Phylogenetic relationships of the resulting entities were established using cox1 combined with partial 16S rRNA and 28S rRNA sequences. Ten national parks were assessed for their species richness, phylogenetic diversity (PD) and endemism. We were particularly interested in the contribution of endemic species to PD. Congruence between molecular and taxonomic identifications was high (91%), with 69% of sampled species endemic to Madagascar. Interestingly, we found that PD at a site was negatively correlated to the proportion of endemic species, most likely because endemics are the result of recent radiations with relatively little branch-length contribution to the measure of PD. This suggests that ranking sites for conservation priority based solely on PD potentially disfavor endemic species by underrating areas where the evolutionary process is most active.     

Large-scale estimators of threatened freshwater catchment species relative to practical conservation management

Freshwater ecosystems are among the most threatened in the world. In light of the threats to freshwater biodiversity, it is essential to map the distribution and status of species to ascertain their threat status for prioritizing conservation action. However, while there is agreement that the conservation of freshwater ecosystems depends on whole-catchment management, there are still a wide variety of large-scale mapping methods in use, the advantages and disadvantages of which have not been fully explored. This study shows that area estimation based on minimum convex polygons should not be encouraged for aquatic species. The IUCN definition of area of occupancy (AOO) is a useful term, albeit highly scale-dependent, for assessment of the total approximate area over which a species occurs. However, for aquatic fauna, and perhaps many other organisms, assessment of occurrence should be based on the more accurate point-locality presences only. The IUCN extent of occurrence (EOO), for freshwater catchment species, should be redefined as ‘the sum of the smallest hydrological units identified, of presently known, inferred or projected occurrences of a taxon, excluding cases of vagrancy, that are used to estimate the threat to a taxon’. A single hydrological unit is also the conservation or management unit. Here we suggest that this unit is the quaternary catchment. This new mapping approach is more appropriate and practical for use in both management planning and conservation action. We suggest that conservation managers and decision makers facilitate co-operation in freshwater mapping efforts by working at the same spatial scale, i.e. the same hydrological unit.     

The fish fauna of mountain streams in South Korean national parks and its significance to conservation of regional freshwater fish biodiversity

The fish fauna of mountain streams in the Jiri (440 km²) and Seorak (373 km²) National Park areas of South Korea was investigated from September 1998 to May 2001. A total of 5979 fish were collected and classified into 22 families and 60 species from both national parks. At Jiri, 30 species in 12 families of fishes were collected, while at Seorak there were 42 species in 17 families. Zacco temmincki [relative abundance (RA) 47.9%] was dominant at both parks. Subdominant species were Rhynchocypris kumkangensis (RA 10.8%), Zacco platypus (RA 9.4%), and Pungtungia herzi (RA 5.3%). A total of 20 species were found to be Korean endemic species, representing seven families. The relative abundance of Korean endemic species was higher at Seorak (30.5%) than Jiri (18.5%). One exotic species (Oncorhynchus mykiss) and two species translocated outside their native catchments (Hypomesus nipponensis and Coreoperca herzi) were collected. The proportion of Korean endemic freshwater fish species in both parks (33.3%) was higher than the overall proportion on the Korean peninsula (23.6%). Within the 14 South Korean mountain-area national parks as a whole, larger parks tend to have higher fish diversity. We conclude that South Korean national parks are important for conservation of the regional fish fauna, especially for endemic and endangered species. Current threats to conservation of fishes within South Korean national parks are identified and management solutions are suggested.     

Endemic freshwater invertebrates from southern France: Diversity, distribution and conservation implications

Freshwaters ecosystems continue to face pressures from pollution, flow regime alterations, habitat destruction and exotic species invasions despite their unique biodiversity. In Europe, National Parks and Special Areas of Conservation aim to provide protection of ‘aggregate’ biodiversity, yet inspection of priority species lists for these sites often reveals a focus towards terrestrial species. In regions such as the Alps and the Pyrénées, this is a particularly serious problem because climate change and other anthropogenic pressures (e.g. hydropower, tourism) are causing widespread hydrological modification which is likely to drive changes in aquatic species abundance, diversity and distribution. Improved understanding of the diversity of rare plants and animals is necessary so efforts can be cost-effectively targeted to conserve the maximum number of species, whilst a clearer picture of these species’ distributions is a precursor to targeting conservation efforts. This paper reports results of a study into the diversity and distribution of 17 endemic mayflies, stoneflies and caddisflies from 598 rivers sites across southern France. Endemic macroinvertebrates were found only at sites in the Pyrénées mountain range with richness peaking at 1500–1800 m above sea level. Nine of these 17 species were recorded from <20 sites and two (Protonemura angelieri, Rhithrogena kimminsi) were found at only 10 sites. Despite both the rarity of these species and threats to their existence, none of them have any current conservation status. New conservation policies for freshwater ecosystems in the French Pyrénées need to be developed as a priority due to the rarity of many aquatic species in this area, growing threats to their existence (habitat modification, hydrological change), and to recognise their importance in food webs that may include other rare species of conservation value.     

Importance of cryptic species for identifying ‘representative’ units of biodiversity for freshwater conservation

Nested systems of biodiversity classification are commonly used for designating protected area networks in terrestrial and marine realms. Whilst terrestrial-style protected areas are largely inappropriate for freshwater systems, the concepts of ‘representative’ biodiversity and ‘complementarity’ can be borrowed for freshwater conservation. Cryptic species are commonly found in freshwater macroinvertebrates and fish, and most have restricted distributions relative to the described conglomerate ‘species’. This indicates that ‘representative’ and therefore ‘complementary’ units of freshwater biodiversity may be smaller than previously appreciated. Using recently detected cryptic species in atyid shrimps from eastern Australia (Atyidae: Paratya australiensis, Caridina mccullochi and C. indistinca), we tested predictions about regional patterns of cryptic assemblage structure, endemism and Phylogenetic Diversity (PD) at the river scale, and discussed their implications for freshwater conservation. Patterns of distribution in these cryptic shrimp species largely corresponded with published distributional patterns of cryptic species in several freshwater fish in eastern Australia, and indicated the presence of four putative ecoregions within a previously recognised freshwater fish province (Eastern Province). However, some rivers had pronounced cryptic endemism, suggesting that rivers may not be ‘representative’ of one another’s biodiversity even within ecoregions. PD and endemism were largely correlated with one another, as endemics typically co-occurred with widespread species at the river scale. This study indicates that cryptic species can contribute to defining patterns of biodiversity at nested spatial scales that may be important for freshwater conservation.     

Aspects of the ecology and conservation of Sri Lanka's endemic freshwater shrimp Caridina singhalensis

The range of distribution of the freshwater shrimp Caridina singhalensis (Ortmann, 1894) (Crustacea: Decapoda: Atyidae), which is endemic to Sri Lanka, has been determined. Although this shrimp was earlier recorded from a number of streams in the highest part of Sri Lanka, where the annual mean temperature is less than 15°C, it is now present in only one stream, in a stretch of about 10 km, on the Horton Plains, situated in the highest peneplain about 2100 m above mean sea level. The population of this shrimp increases from April to September and decreases from October to March, and these fluctuations appear to be related to rainfall and temperature. Some measures to protect this species are suggested.     

The conservation game

Conservation problems typically involve groups with competing objectives and strategies. Taking effective conservation action requires identifying dependencies between competing strategies and determining which action optimally achieves the appropriate conservation goals given those dependencies. We show how several real-world conservation problems can be modeled game-theoretically. Three types of problems drive our analysis: multi-national conservation cooperation, management of common-pool resources, and games against nature. By revealing the underlying structure of these and other problems, game-theoretic models suggest potential solutions that are often invisible to the usual management protocol: decision followed by monitoring, feedback and revised decisions. The kind of adaptive management provided by the game-theoretic approach therefore complements existing adaptive management methodologies.     

The conservation of the Cape Barren goose

Increasing numbers and annual production of Cape Barren geese have led to conflict between the geese and farming interests. The present reserves are inadequate to provide for the future of the geese and a new State Reserve is proposed. Further, a management programme is urgently needed to provide the necessary habitat conditions and to find ways of converting their pest status into a conservation asset for the public.