Aquatic Conservation Marine and Freshwater Ecosystems

Published by Wiley
Online ISSN: 1099-0755
Print ISSN: 1052-7613
1.Rhodolith beds, unattached coralline reefs, support a high diversity and abundance of marine species from both hard and soft benthos. We used surveys in multiple shallow (3–20 m) beds in the Gulf of California to (1) examine seasonal patterns in associated floral and faunal diversity and abundance, (2) compare differences in faunal associations between rhodolith beds and adjacent sedimentary habitats, (3) examine the importance of complexity of rhodolith structure to community structure, and (4) estimate the impact of anthropogenic disturbance on rhodoliths and associated species.2.Macroalgal richness was seasonal, and beds supported higher richness in winter (to 36 species) than summer (6–7 species), primarily due to foliose red algae. Strong seasonal variation in the abundance of dominant cover organisms was due to a shift from macroalgae and mat-forming colonial invertebrate species to microalgae.3.The community in a rhodolith bed of high-density thalli (El Coyote average ∼11000 thalli/ m−2) had higher richness (52 versus 30 species) and abundance of epibenthic and crypto- and in-faunal species compared with an adjacent sand community. Species diversity and abundance was particularly high for unique cryptofaunal organisms associated with rhodolith interstices. Cryptofauna reached average densities of 14.4 organisms/ cm−3 rhodolith, the majority of which were crustaceans, polychaetes and cnidarians along with rhodolith-specific chitons.4.Results from sampling across a range of rhodolith morphs in the El Requeson bed (with lower average cryptofaunal densities of 2.3 organisms/ cm−3) revealed that the total organisms supported by a rhodolith significantly increased with both complexity (branching density) and space available (thallus volume). These data suggest that reducing the population size structure, structural complexity and cover of living rhodoliths could decrease species richness and abundance.5.While disturbance is a natural feature of these free-living beds, increased anthropogenic disturbance from trawling, anchoring and changes in water quality can directly impact the bed community through substrate alteration. Commercial fishing threatens rhodolith beds in the Gulf of California by decreasing rhodolith size and increasing sedimentation and burial rates. In addition to reducing direct destruction, conservation efforts should also focus on decreasing practices that breakdown thalli. Copyright © 2003 John Wiley & Sons, Ltd.
1.Although the Doñana National Park is given the highest degree of environmental protection in Spain, it is likely that groundwater discharge to several ponds within the Biological Reserve has been damaged by abstraction to a tourist resort located less than 1 km away.2.Hydrological changes were monitored over 16 years (1 October 1989 to 30 September 2005) by recording the shallow water table of six temporary ponds at 1–8-week intervals, and the duration of pond wet phase (or hydroperiod) during each hydrological cycle.3.The average rainfall for the study period was 563.2 mm, and included 6 wet, 5 moderate, and 5 dry years in a seemingly random sequence. The average rainy season extended from October until the end of March, while the dry season occupied the rest of the year.4.The water table generally oscillated following this alternation of rainy and dry seasons, but this fluctuation was minimal during dry years, and even failed to occur at some ponds.5.Since 1998/99, the average hydroperiod has shortened by 3 months at Charco del Toro pond, and by almost 2 months at Brezo pond, while the rest of the ponds exhibited a reduction of less than 1 month.6.Vegetation changed in the ponds between May 1990 and 2005. Total plant cover increased (range of increase: 16–65%), and species richness decreased in all ponds (range of species loss: 4–18).7.The reduction in the hydroperiod probably enhanced the growth of a few woody plants to the detriment of flooding-dependent species as the cover of Pinus pinea increased nearly fourfold at Brezo pond, while that of Scirpus lacustris was halved at Charco del Toro pond.8.The pumping area for the nearby tourist resort should be relocated, and a specific management strategy should be developed in order to prevent further damage to the ponds. Copyright © 2007 John Wiley & Sons, Ltd.
1.Zingel asper (a percid) is a highly endangered endemic fish of the Rhone catchment (France). Scale reading was used to estimate age and growth rates in one of the two last remaining populations that are still present in relatively high densities (River Beaume).2.Scale reading was validated for the first time in Z. asper by comparing back-calculated lengths from scale annual increment to actual lengths obtained by individual mark–recapture monitoring. The impacts of age or sampling site on individual growth rates were explored using generalized linear models.3.No major discrepancy was observed between actual and back-calculated lengths. Longevity of Z. asper was inferred from the age data and did not exceed 3 years. Results showed variation in growth rates among ages (20 times higher for 1+ fish than for 2+ or 3+ fish) and also among sampling sites.4.The present work provided the first estimates of annual growth rates in the Beaume population. This study also showed that scale reading allowed a valuable trade-off between accuracy and conservation imperatives that often imply avoiding invasive techniques such as the implantation of passive integrative transponders.5.Scale reading will be a valuable tool for future ecological studies in Z. asper and will help in developing conservation strategies for this species as longevity and growth patterns are two life-history traits of major importance for the management of endangered populations. Copyright © 2007 John Wiley & Sons, Ltd.
1. Margaritifera margaritifera populations are declining throughout its range, including Ireland, despite legislation designed to protect freshwater pearl mussels and their habitat. 2. A survey of freshwater pearl mussels was carried out on rivers in County Donegal, north-west Ireland, to determine the current distribution, size and density of M. margaritifera populations, as well as to identify potential threats to mussels there. 3. The survey revealed the freshwater pearl mussel to be widespread, particularly in the western half of the county. However, densities of mussels at most sites are low, with just two sites having mussel densities of over 5 m−2. Furthermore, the species appears to be absent from a number of sites from which it had been previously recorded. 4. According to the literature, there is a long history of pearl fishing in Co. Donegal and neighbouring counties. Evidence from heaps of shells found on the river bed and banks at several sites and recent anecdotal reports from local people suggest pearl fishing is being practised on all rivers investigated during the present study. 5. The main conservation requirements for M. margaritifera populations in Donegal are to maintain water quality at its present high standard and, as pearl fishing appears to be a widespread and immediate threat to the remaining mussel populations, to enforce existing legislation designed to protect M. margaritifera.
1.The species diversity of inland waters is among the most threatened of all ecosystems and in many parts of the world it is in continuing and accelerating decline. Such decline could be restrained by acknowledging the scope of target species, so that all relevant stages in their life cycle are considered.2.The gharial Gavialis gangeticus is a prominent riverine species of the Indus, Ganges, Brahmaputra and Mahanadi river systems that is becoming increasingly rare due to reduction in water flow and available nesting beaches, modification of river morphology and increased mortality in fishing nets. Despite these threats, scientific information on habitat selection by gharial is still inadequate, which hinders conservation measures.3.This paper presents the population status, basking site selection and water depth preferences of different size-classes of gharial based on a study conducted in the National Chambal Sanctuary, India.4.Between 1992 and 2007 a 40% decline in the gharial population was observed in the National Chambal Sanctuary. The decline was prominent in the recruitment class (<120 cm), which primarily comes from the nests laid in the wild, and also in sub-adults (>180 to 270 cm) comprising both wild and reintroduced gharial.5.Along the Chambal River, gharial preferred sandy parts of the river banks and sand bars for basking and showed less preference for rocky river banks and rocky outcrops. Clay river banks were least preferred.6.Juvenile gharials <120 cm and 120–180 cm preferred water depths 1–3 m and 2–3 m, respectively. Gharial >180 cm (including sub-adults and adults) preferred water depths >4 m.7.Increasing demands for sand for development activities, and water abstraction for irrigation and energy generation coupled with mortality in fishing nets, are likely to affect gharial and other aquatic species, and steps need to be taken to maintain the minimum river flow necessary to sustain ecosystem processes. Copyright © 2009 John Wiley & Sons, Ltd.
1.A population of Enochrus bicolor (Fabricius) was monitored over a 4-year period (March 1997–March 2001) from a coastal brackish pool in S.E. Essex. This water beetle, together with Ochthebius marinus (Payk.), O. viridis Peyrhiff, O. punctatus Steph., Hygrotus parallelogrammus (Ahrens), Berosus affinis Brulle, Agabus conspersus, (Marsham), Rhantus frontalis (Marsham), R. suturalis (MacLeay), Paracymus aeneus (Germar), and Haliplus apicalis Thompson, are all taxa of conservation interest.2.Enochrus bicolor was present in most months, with greatest adult abundances being recorded in August and September each year.3.During the study period salinity values ranged from 4.7 ppt (parts per thousand) to 62.6 ppt.4.Correlation analysis and the development of regression models indicated that the highest abundances of E. bicolor coincided with maximum water temperature in the late summer–early autumn. However, when the natural seasonal signal was removed by standardizing the series, a relatively weak association with the relative abundance of E. bicolor and conductivity was observed.5.The conservation of E. bicolor and other organisms associated with brackish water habitats subject to irregular marine inundation is considered. Copyright © 2002 John Wiley & Sons, Ltd.
1. This paper summarizes aspects of the biology and conservation of the grey nurse shark (Carcharias taurus) in south-eastern Australian waters. This species has been a totally protected species in the State of New South Wales since 1984 and, as far as is known, was the first protected shark in the world. 2. Aspects discussed include systematics and taxonomy, distribution and biogeography, morphology and behaviour, reproduction and migrations, feeding habits, fisheries value and claims of attacks on humans, and impacts of protective beach meshing, spearfishing and SCUBA diving. The background to, and history of, moves to protect and conserve the species in New South Wales waters are also covered. 3. Results of surveys of the abundance of this species at Seal Rocks, an area off the mid-north coast of New South Wales where grey nurse sharks are known to aggregate, are reported. Also, a summary of the results of a telephone survey of commercial dive shop operators regarding the occurrence of grey nurse sharks along the New South Wales coastline is presented. 4. Finally, recommendations are made concerning the need for further research on, and management of, this species in Australian waters.
1.This study is the first attempt using Levins's Theory (loop analysis) in order to develop a sustainable management for the scallop, Argopecten purpuratus, fishery in Peru during El Niño-Southern Oscillation events (ENSO) and upwelling conditions. Based on this theoretical framework, it was possible to estimate the local stability for each of these model systems and to follow the qualitative changes of the variables in response to external factors.2.Based on our results, we suggest the following management policies to be implemented: (1) during ENSO events the size at the first capture of the scallops should be >70 mm and (2) the increase in the number of fishermen during ENSO events must be prevented. Both measures increase the sustainability of fishery under ENSO and upwelling conditions. The ecological models predict that during ENSO and upwelling events, any management strategy to increase the recruitment of the scallop would not have a positive impact on the adult stock.3.Finally, we suggest that more efforts must be focused on the development of extended eco-social models, which incorporate further social and economic variables, increasing realism of the abstractions for this fishery activity. Copyright © 2002 John Wiley & Sons, Ltd.
One of the experimental boxes used in this study. 
Frequency histogram of the number of eggs spawned by 50 northern spectacled salamanders in each type of water, or found on the polystyrene floor (OUT). Legend: OWN ¼ home breeding water; OTH ¼ not-home breeding water; DIS ¼ distilled water; MIN ¼ mineral water. 
1.The conservation of small aquatic habitats is fundamental to preserving diversity in Mediterranean freshwater ecosystems. Amphibians are particularly endangered, as their chemical world, represented by both abiotic and biotic scent trails, is highly susceptible to environmental changes.2.Breeding site fidelity in the northern spectacled salamander, Salamandrina perspicillata, an Italian endemic vertebrate, was investigated with respect to the ability of this species to locate its own home water rather than that from other places. The choice of aquatic habitat for spawning was investigated in dark conditions by comparing different types of experimental water (home breeding water vs. breeding water of allopatric populations vs. mineral water vs. distilled water). Fifty-eight reproductive females were collected at four breeding sites in the Lepini Mountains (Latium, central Italy). The number of eggs spawned by each specimen in the different types of experimental water was counted.3.The very large majority of the eggs were found in the home breeding water. When the eggs counted in the other types of water were compared, no differences were found.4.These findings revealed that in the northern spectacled salamander the choice of spawning site was affected by the scent trail of its own aquatic habitat. This new information has improved knowledge of the auto-ecology of S. perspicillata, thus contributing to strategies for its conservation. Copyright © 2007 John Wiley & Sons, Ltd.
1. Modern records of 165 species of wetland beetle (Haliplidae, Hygrobiidae, Noteridae, Dytiscidae, Gyrinidae, Georissidae, Hydrochidae, Helophoridae, Hydrophilidae, Hydraenidae, Scirtidae, Dryopidae, Elmidae, Chrysomelidae, Curculionidae) were assembled for analysis. 2. Two hundred and eighty nine modern lists of seven or more species of water beetle from sites in Ireland were subjected to multivariate analysis. 3. Ten assemblage types were identified using TWINSPAN. Habitats typical of these assemblages are: A. deep rivers; B. rivers with riffles; C. puddles; D. canals and lakes with rich vegetation; E. ponds and ditches; F. turloughs; G. natural, minerotrophic fens; H. base-flushed cutover bogs; I. peat bogs; J. montane flushes. The distribution of these types is discussed. 4. Ordination of site data by DECORANA indicated that the important environmental variables dictating water beetle assemblage type in Ireland were: flow; water permanence; exposure; type of substratum. Acidity could not be isolated as a determinant, except within the analysis of assemblage types conducted using TWINSPAN. DECORANA isolated one brackish site as an outlier but salinity was not otherwise a major factor, probably because few brackish sites were included in the analysis. 5. The number of modern records for each species was used to provide a provisional set of species-quality scores. A simple rationale was devised to weight these scores in favour of relict species and against elusive species, species with short-lived adults and species primarily associated with man-made habitats. 6. The average species-quality score per site and the number of species recorded were used to rank sites within each TWINSPAN end-group. The most diverse sites with the highest quality were some turloughs, rich fens and base-flushed peat cutting complexes. Some montane lakes and flushes with relatively few species had high species-quality scores.
1.Diatom assemblages of man-made coastal dune wetlands between Blankenberge and Heist (Belgium), dating from 1852 to 1929 and sampled from herbarium specimens of macrophytes, were compared with more recent samples collected in the remaining calcareous dune marshes and pools in this area.2.Overall, nutrient conditions inferred from the reference assemblages were fairly eutrophic for phosphorus. Only a minority of the historical assemblages pointed to presumably nitrogen-limited conditions.3.Significant alterations in general assemblage composition were observed, including a marked decline of epiphytic species, and a decrease in the compositional variation in sediment diatom assemblages. These changes can be attributed mainly to an increased availability of nutrients and degradable organic matter since the mid 1970s. No changes in the salinity range seem to have occurred, suggesting fairly stable hydrological conditions.4.Possible causes for eutrophication include increased atmospheric deposition of nutrients, but also more site-related phenomena such as guanotrophication, angling and, perhaps, effects of nature management on soil–nutrient cycling. Their relative importance needs to be established and further monitoring is necessary.5.Measures are required to reduce nutrient levels of both permanently and periodically inundated sites and to promote small-scale habitat differentiation. Due to physical constraints, the latter will be possible only by mimicking the processes that act upon more natural dune systems in management practice. Copyright © 2003 John Wiley & Sons, Ltd.
Age-frequency histograms of live mussels observed at (a) Bear Creek and (b) Battle Creek in 1995 and 2006. Sample sizes in parentheses.
Age–frequency histograms of empty shells observed at (a) Bear Creek and (b) Battle Creek in 2006. Sample sizes in parentheses. 
Age-frequency histograms of empty shells observed at (a) Bear Creek and (b) Battle Creek in 2006. Sample sizes in parentheses. 
Age-specific estimates of (a) overall survival (S) and (b) instantaneous mortality (Z) in Bear Creek and Battle Creek mussel populations. 
1.Two western pearlshell (Margaritifera falcata) populations in western Washington were surveyed in 1995 and re-surveyed in 2006. Significant declines in mussel numbers had occurred in both streams during the past decade.2.In Bear Creek, overall density dropped from 56.0–6.9 mussels m−2, and in Battle Creek, overall density dropped from 80.7–13.4 mussels m−2 in 2006.3.Large numbers of empty shells were found in Bear Creek in 2006, indicating high levels of mortality. A disproportionate loss of large, old mussels resulted in a forward shift in modal age class, from 51–60 years to 31–40 years.4.In Battle Creek, survival appeared to be higher, although significant numbers of shells were found in places. A lack of juvenile mussels indicated recruitment problems, possibly due to habitat degradation following colonization of the stream corridor by beavers and/or a lack of migratory host fish.5.Effective remedial actions for the Bear Creek and Battle Creek M. falcata populations are required within the next 5–10 years and 50 years, respectively, in order to ensure their long-term survival. Copyright © 2007 John Wiley & Sons, Ltd.
1. Despite the ecological, environmental, and economic importance of mangroves, they are declining at an alarming rate worldwide, mostly as a result of human activities. 2. Along the eastern African coast, Mozambique has the largest mangrove area. Fishing and farming are the main economic activities in the area, and people harvest mangrove vegetation for tannins, fuel wood, traditional medicine, boat-building, carpentry, and crafting. 3. Landsat 5 TM imagery was used to map the distribution of trans-boundary mangrove areas along the Mtwara–Quirimbas Complex. Results for 1995 and 2005 are presented for the entire coastline and in more detail for the Ruvuma estuary, Quiterajo, Ibo/Quirimba islands, and Pemba Bay. Results were validated with a ground- truthing excursion in 2006, showing an overall thematic accuracy of 73%. 4. Total estimated area of mangrove was 357km2in 1995 and 368km2in 2005, with the small net gain of 3% corresponding to a total gain of 32km2and a total loss of 21km2over this decade. 5. Results suggest that although Landsat TM imagery can be effective in mapping mangrove distribution, caution must be used in inferring its ecological condition.
1. Falkland Islands' tourism is evolving at an increasing pace. A record number of passengers, 23 497, visited the Islands during the 1999-2000 season. This rise was due to an increase in both the frequency of vessel visits and the average passenger capacity of vessels, with the number of luxury cruise ships of > 1000 passengers steadily increasing. The Falklands' industry is made up of three types of vessel: the expedition cruise vessels (ca. 100-200 passengers); larger cruise vessels (ca. 400 passengers), and the luxury cruise vessels (ca. 1000 passengers). 2. The cruise ship industry has seen a diversification within the market, with cruises now available to a wider audience thus increasing the need for new experiences and landing sites. A similar diversification is being seen within the Islands themselves as the capacity to take larger vessels at remote sites is being developed. Whilst the expedition cruise vessels visiting the Islands are operating to high environmental standards as members of the International Association of Antarctic Tour Operators (IAATO), vessels with 400+ passengers may not become members of IAATO, due to Article III of the organization's Bylaws which limits the number of passengers. These larger capacity vessels are therefore not subject to the same self-regulating guidelines. The implications of increasing passenger numbers in the islands are discussed with regard to pressures on both the wildlife and vegetation. 3. This study outlines the need for an island-wide approach and a legislative framework to ensure high standards of operation are adhered to within the Islands from all visiting vessels and that accurate information is provided to all visitors along with a suitable code of conduct. The collection, collation and analysis of visitor data to identify trends and implement appropriate management strategies, and further research into the potential impacts of tourism on wildlife in the Falklands are also recommended.
1.One of the goals for Natura 2000, a key European Community programme of nature conservation, is to produce a network of protected areas. An analysis of the Natura 2000 marine sites proposed in the most recently agreed list for the Atlantic region (northern Portugal to Denmark, n=298) was used to characterize the network in terms of site areas and inter-site distances. Sites were considered as part of the network when they included any of the marine Natura 2000 Annex I habitat types found in the Atlantic region (excluding lagoons).2.The median size of individual sites was 7.6 km2 with a median separation among neighbouring sites of 21 km (range 2–138 km).3.A connectivity analysis was used to identify the potential reliance of species on areas of habitat outside the proposed network. This analysis was based on the assumptions that: (a) species with low dispersal capacity will persist in sites when local reproductive effort sustains the resident population and (b) greater dispersal scale will link sites in the network, but implies a greater loss of recruits from the local population. For intermediate dispersal scales (2–20 km), at least half of the proposed sites are likely to be both too small and too isolated to support populations in the network. The conservation of intermediate dispersers in such sites may therefore be more dependent on habitat outside the network than is the case for other dispersal capabilities. Species with both dispersal scales above 20 km and low habitat specificity may have a metapopulation structure with exchange of dispersing individuals occurring among protected sites. Species with increasing degrees of habitat specificity will need dispersal scales greater than 20 km to avoid dependence on areas outside the proposed network.4.Most sections of the Atlantic region coastline contain proposed Nature 2000 sites. An analysis of site area and average isolation at the 1° latitude by 1° longitude scale indicated that relatively well designated sections (in terms of area and site spacing) of the coast were interspersed with less well designated sections. Analyses of overall habitat availability and population genetic studies are required to assess the significance of varying levels of protection at this scale. Copyright © 2007 John Wiley & Sons, Ltd.
1. A total of 950 251 individuals of 157 turtle species were recorded during a 35-month survey of the turtle trade in Hong Kong, Shenzhen and Guangzhou, southern China. All but two of the 157 species were encountered in Hong Kong; Guangzhou ranked second in diversity (113 species) and Shenzhen third (89 species). Together, these turtles made up around 60% of the global chelonian fauna; 124 (∼80%) of them were freshwater turtles. 2. Seventy-two globally threatened species were traded in southern China during the survey: 13 classified by the IUCN as critically endangered (CE), 29 as endangered (EN), and 30 as vulnerable (VU). Thirteen species listed on CITES Appendix I and 64 species on Appendix II, as well as eight species nationally protected in China, were traded. 3. The majority of species traded had natural ranges that included China and neighbouring Southeast Asian countries, or Southeast Asian countries other than China. These non-Chinese Asian turtles (primarily Bataguridae) constituted around two-thirds of the 77 species in the food trade, and turtles sold as food accounted for 73% of individuals encountered during the survey. Most species sold as food were also traded as traditional Chinese medicine, and nearly all turtles (155 of 157 species) were sold as pets. Eighty-one species were traded only as pets. 4. Large numbers of Cuora galbinifrons (CE; CITES-II) were traded (> 15 000 individuals) and even greater quantities (> 210 000 individuals) of C. amboinensis (VU; CITES-II), as were significant numbers of other CR, EN and VU batagurids. Observed levels of exploitation of wild populations appeared unsustainable. 5. Enforcement of relevant CITES regulations during the survey seemed limited and globally threatened Asian species remained in trade in Hong Kong without the relevant licences. Trade within China is not subject to CITES, but could be regulated by enforcement of existing national laws and expansion of protected-species lists.
1.This study examines the perceptions of 500 Sri Lankan fishers about influences on the outcome of the 2004 Asian tsunami. It is based upon analysis of questionnaire data on 13 natural environmental and development risk factors, in relation to human deaths and house damage (impact indicators).2.Mangroves, coral reefs and sand dunes afforded protection against tsunami damage (67–94% of fisher responses), as did housing and roads.3.Fishers overall believed rivers/estuaries, concave coastlines and hotels exacerbated impacts. However, a significantly greater proportion of fishers living within 100 m of the coast reported that rivers/estuaries had a protective role than those living further inland. Rivers seemingly diverted ‘tsunami water’ far inland, where it overflowed and caused damage.4.Risk and damage are multi-faceted concepts and measurable in different ways. Findings are considered in the light of ecological studies and modelling, with special reference to mangroves, whose alleged protective role has become equivocal during post-tsunami research.5.Insights of fishers and other communities with intuitive knowledge add a valuable perspective to the understanding of natural disasters and environmental change. This approach is seen as complementary rather than an alternative approach to purely ‘scientific’ research. Copyright © 2008 John Wiley & Sons, Ltd.
DCA showing site groupings according to TWINSPAN on (a) the lake-scale species composition, where 4 represents group 1, * group 2, & group 3 and  group 4 and (b) the micro-habitat-scale species composition, where  represents group 1, 4 group 2 and * group 3. Also see Table 1. 
Environmental conditions of the lake-scale plant community groups. Values with different letters are significantly different (p50:05; Kruskal-Wallis test and
Environmental conditions of the micro-habitat-scale plant community groups. Values with * are significantly different (p50:05; Mann-Whitney U test)
1.Najas flexilis (Willd.) Rostk. & Schmidt is a submerged annual macrophyte, rare in Europe, which is protected under the EC Habitats Directive.2.N. flexilis grows in deep, often coloured or turbid water in mesotrophic lakes. Because of this habitat preference it is difficult to locate and assess the ecological state of populations of the species for conservation monitoring purposes.3.A method is described based on plant community information that can be used to determine the baseline probability that conditions in a lake are suitable for supporting N. flexilis growth. This can be applied to conservation management decisions, such as whether a detailed underwater survey is justified for monitoring the integrity of existing populations of N. flexilis, or whether the lake may be a suitable site for introduction, or reintroduction, of populations of the plant.4.Two methods of plant community description are compared: a quantitative micro-habitat scale approach and a whole-lake-scale qualitative approach. Plant community data collected using each method were grouped using TWINSPAN, and environmental descriptors of the sites comprising each plant community group were compared statistically.5.Micro-habitat-scale community groups differed significantly only in the light extinction coefficient, indicating the zone within the lake in which N. flexilis occurred.6.The whole-lake-scale community groups differed in a number of environmental variables indicative of eutrophication and acidification, two major environmental threats to N. flexilis survival.7.This study suggests that a lake-scale qualitative plant community description would be a better indicator of site suitability for N. flexilis growth than a quantitative micro-habitat plant community description. This is because the whole-lake-scale approach could detect a difference in the environmental factors that affect N. flexilis growth, which the micro-habitat scale approach could not. Copyright © 2005 John Wiley & Sons, Ltd.
1.A short sediment core from Lake Morenito was studied to assess the impact of environmental changes on chironomid communities occurring during the last ca 100 yr.2.Lake Morenito (41°S, 71°W) is located 20 km west of the city of Bariloche, in northern Patagonia, Argentina. Before 1960, this lake was a branch of Lake Moreno; by that time, an artificial dam closed the system, establishing the new lake. Another human disturbance that took place during the time span of the core was the introduction of salmonids to the area ca 1910.3.The most important natural events that occurred in the area during the last 100 yr were related to volcanic episodes. One of them, occured in Chile in 1960 affecting the Argentinian side, coincided with the dam's construction.4.Changes in the chironomid community were recorded by studying the sub-fossil remains (the chitinized head capsule of the larvae) present in the sedimentary sequence. The results show that volcanic tephra layers deposited along the core led to a sharp instantaneous drop in the diversity and abundance of chironomid assemblages. Human activities are also associated with a change in chironomid community composition.5.Chironomus reached its maximum abundance values in 1910 and 1960. The organic matter content also increased at the same time. The increase of Chironomus after 1910 is clearly related to an increase in the trophic status of the lake. However, owing to the synchronicity of events in 1960, i.e. the volcanic event and the dam's construction, it is difficult to establish whether the change in the chironomid assemblage was in response to an increase in trophic enrichment, to natural disturbance, or both. Copyright © 2004 John Wiley & Sons, Ltd.
1.Ponds and pools, broadly defined in this paper to include all small and shallow standing waters that permanently or temporarily contain water, are numerous, diverse and important from a conservation point of view. We here argue that ponds and pools offer powerful potential for studies in ecology, evolutionary biology and conservation biology.2.An outline is given of the characteristics of pools and ponds that make them good model systems for large-scale surveys and hypothesis testing through experimental manipulation. Such studies will not only increase understanding of community and genetic structure, as well as of patterns of biodiversity, in small aquatic habitats themselves, but may also contribute significantly to testing general theory.3.These merits are illustrated by the recent progress on the understanding of the relative importance of local versus regional factors in structuring populations and communities, as well as of the impact of hydroperiod on community and ecosystem functioning. Copyright © 2005 John Wiley & Sons, Ltd.
(a) Loop Model I and (b) loop Model II. Holistic sustainability measures (Fn and 28criterion). (Lt ¼ Lessonia trabeculata, Tn ¼ Tetrapygus niger, OM¼ other macroalgae, H ¼ other herbivores, Rt ¼ Rhynchocinetes typus, SE ¼ small epifauna, SS ¼ starfish; and C ¼ crabs).  
Loop Model III. Holistic sustainability measures (Fn and 28criterion). Two alternative management scenarios are shown. (Lt ¼ Lessonia trabeculata, Tn ¼ Tetrapygus niger, OM ¼ other macroalgae, H ¼ Other herbivores, Rt ¼ Rhynchocinetes typus, SE ¼ small epifauna, SS ¼ starfish; C ¼ crabs; Pch ¼ Pyura chilensis, Bar ¼ barnacles; Ct ¼ Calyptraea trochiformis, CcJ ¼ Concholepas concholepas juvenile, CcA ¼ C: concholepas adults, PP ¼ primary producers, and Fi ¼ fishes).  
Loop eco-social Model V. Holistic sustainability measures (Fn and 28criterion). (Lt ¼ Lessonia trabeculata, Tn ¼ Tetrapygus niger, OM ¼ other macroalgae, H ¼ other herbivores, Rt ¼ Rhynchocinetes typus, SE ¼ small epifauna, SS ¼ starfish; C ¼ crabs; Pch ¼ Pyura chilensis, Bar ¼ barnacles; Ct ¼ Calyptraea trochiformis, CcJ ¼ Concholepas concholepas juvenile, CcA ¼ C: concholepas adults, PP ¼ primary producers, Fi ¼ fishes; HdR ¼ Haliotis discus hannai recruits, HdJ ¼ H: discus hannai juvenile, and HdA ¼ H: discus hannai adults, F ¼ fishermen; Far ¼ cultures; M ¼ market; and Pr ¼ price of the abalone).
1.Loop models of ecological and socio-economic systems were developed to analyse and predict the impact of a possible accidental introduction (escapes) of the abalone Haliotis discus hannai into a benthic community of north-central Chile.2.Although the ‘new’ ecological system resulting from a successful invasion of abalone would be locally stable, the establishment of a self-enhanced dynamic of recruits would transform this into an unstable system.3.The harvest of the kelp, Lessonia trabeculata and other macroalgae is not recommended because this destabilizes the system. The harvest of abalone adults is only sustainable if they do not exert a negative effect upon other native invertebrates.4.The eco-social model showed three important results: (1) if the variables ‘Price’ and ‘Farming’ are in expansion and stationary dynamics, then the models were found unstable; (2) a self-enhanced dynamic of abalone recruits tends toward instability; and (3) the harvest of the kelp L. trabeculata and other macroalgae would be non-sustainable.5.Based on our results, the sustainable development of extensive farming of H. discus hannai in the sea would be not reached. If it is done, an intensive monitoring of the community after introduction into the system is strongly recommended. Likewise, the farming of macroalgal species (source of food for abalone) should be promoted in order to avoid harvesting of macroalgae from natural systems. Copyright © 2006 John Wiley & Sons, Ltd.
1.Multivariate analysis of vegetation and water beetles recorded in the abandoned drains and flooded workings of a cut-over lowland Irish raised bog, Montiaghs Moss, shows that water depth and trophic status are key predictors of plant species composition and that vegetation community structure significantly explains water beetle composition.2.The spatial distribution of secondary and tertiary drains and peat pits influences species composition indirectly, through trophic status, by connecting habitats with primary agricultural drains passing through the bog.3.Habitat isolation and the cessation of drain management promote change in the submerged aquatic vegetation, emergent-swamp and poor-fen habitats recorded by facilitating vegetation development and surface acidification.4.The ecological consequences are likely to be a reduction in the area of open-water habitats, the development of poor-fen vegetation and the subsequent loss of high conservation value species of plants and beetles.5.Management for biodiversity conservation should initially address water quality, for example, through the European Union (EU) Water Framework Directive, followed by restoration to promote structural and spatial heterogeneity of drain and peat-pit habitats.6.At a landscape scale, implementing ditch and peat-pit management across abandoned cut-over lowland raised bog habitats in the farmed Northern Ireland countryside, through EU Common Agricultural Policy agri-environment schemes, would give regional gains. Copyright © 2005 John Wiley & Sons, Ltd.
At present, marine reserves do not represent the full range of community types throughout New Zealand. To assist with the placement of a marine reserve along the Abel Tasman National Park coast (northern South Island), dominant subtidal laminarian and fucoid algae, echinoids and herbivorous molluscs were quantitatively investigated. Results from 100 quadrats collected from 19 random transects at six selected sites showed that algae and grazer assemblages varied between granite and limestone substrata. Granite had a high percentage cover of crustose coralline algae (mean 82%–90%), a sublittoral fringe of brown macroalgae and no Ecklonia radiata or red foliose algae. Limestone sites were distinguished by a relatively low percentage cover of coralline algae (mean 13%) and high cover of foliose red algae and E. radiata (2%–36% cover and 0.2–13.9 stipes m−2, respectively). On limestone, molluscs Turbo smaragdus and Cookia sulcata, and the echinoid Evechinus chloroticus were larger than those on granite. On limestone sites with little macroalgae, herbivore size was intermediate. Grazers were more abundant on granite than limestone (mean 34.6 m−2, and 10.8 m−2 respectively). Differences in herbivore composition were recorded between granite substrata, while both algal and herbivore composition varied between limestone sites. We suggest that a variety of environmental factors including substratum influence algal and herbivore assemblages along the Abel Tasman coast. It is recommended that selection of a marine reserve site or sites along the coast of Abel Tasman National Park recognizes differences in community structure both between and within limestone and granite substrata.
1.Marine protected areas (MPAs) range from multiple-use areas (MUA) to absolute no-take reserves (NTR). Despite their importance for fisheries management, there are few long-term studies comparing benefits from different types of MPAs within the same region.2.Fish assemblages were monitored for five years (2001–2005) in the largest coral reefs in the South Atlantic (Abrolhos Bank, Brazil). Monitoring included one community-based MUA, two NTRs (one established in 1983 and another in 2001), and one unprotected area. Benthic assemblages at these areas, as well as fish assemblages on unprotected deeper reefs (25–35 m), were monitored from 2003 onwards.3.Habitat characteristics strongly influenced fish assemblages' structure. This, together with the lack of data from before establishment of the MPAs, did not allow an unequivocal analysis of the effects of the MPAs.4.Biomass of commercially important fish, particularly small carnivores, was higher in the older NTR. Biomass of black grouper Mycteroperca bonaci increased by 30-fold inside NTRs during the study period, while remaining consistently low elsewhere.5.A single herbivore species, the parrotfish Scarus trispinosus, dominated fish assemblages (28.3% of total biomass). Biomass of this species increased in 2002 on the younger NTR and on the MUA, soon after establishment of the former and banning of the parrotfish fishery in the latter. This increase was followed by a decline from 2003 onwards, after increased poaching and reopening of the parrotfish fishery.6.Fish biomass increased in 2002 across the entire region. This increase was stronger in sites closer to deeper reefs, where fish biomass was up to 30-times higher than shallow reefs: movement of fish from deeper to shallower areas may have played a role.7.The effective use of MPAs in the Abrolhos Bank is still dependent on adequate enforcement and the protection of critical habitats such as deep reefs and mangroves. Copyright © 2008 John Wiley & Sons, Ltd.
1.Growing concern associated with threats to the marine environment has resulted in an increased demand for marine reserves that conserve representative and adequate examples of biodiversity. Often, the decisions about where to locate reserves must be made in the absence of detailed information on the patterns of distribution of the biota. Alternative approaches are required that include defining habitats using surrogates for biodiversity. Surrogate measures of biodiversity enable decisions about where to locate marine reserves to be made more reliably in the absence of detailed data on the distribution of species.2.Intertidal habitat types derived using physical properties of the shoreline were used as a surrogate for intertidal biodiversity to assist with the identification of sites for inclusion in a candidate system of intertidal marine reserves for 17 463 km of the mainland coast of Queensland, Australia. This represents the first systematic approach, on essentially one-dimensional data, using fine-scale (tens to hundreds of metres) intertidal habitats to identify a system of marine reserves for such a large length of coast. A range of solutions would provide for the protection of a representative example of intertidal habitats in Queensland.3.The design and planning of marine and terrestrial protected areas systems should not be undertaken independently of each other because it is likely to lead to inadequate representation of intertidal habitats in either system. The development of reserve systems specially designed to protect intertidal habitats should be integrated into the design of terrestrial and marine protected area systems. Copyright © 2005 John Wiley & Sons, Ltd.
1. The possible impacts of abstraction of water from streams and rivers in the UK have generated concern in conservation bodies. 2. This paper examines the feasibility of using biotic scores and predictions from the computer-based RIVPACS system to assess the effects of abstractions on benthic fauna. 3. Control and ‘impacted’ sites on 22 rivers which experienced abstractions for hydroelectric power generation, supply of drinking water (either directly or through groundwater abstraction), spray irrigation and fish farming, were examined. 4. The ratios of observed to predicted biotic scores and comparison of observed fauna with that predicted by RIVPACS were used to assess the biological quality of the sites. 5. Only 11 of the 51 sites on the 22 rivers showed signs of reduced environmental quality. These included eight sites on a small lowland stream which receives run-off from fertilized agricultural land and is subject to spray irrigation; two sites on upland streams which had experienced severe spates prior to our survey and a small chalk stream, the Pang. 6. Discharge, baseflow, substrate and altitude were factors which explained most of the variation in faunal parameters such as biotic score, numbers of species, numbers of families and total abundance. 7. The main conclusions of the study are that upland streams did not appear to suffer adverse effects as a result of abstraction whereas lowland streams appeared to be more degraded, but with the exception of the Pang this could not necessarily be attributed to abstraction. 8. Biotic scores with RIVPACS cannot be used to set ‘minimum ecological flows’ but can be used either directly, to assess site-quality and to identify areas of concern which may or may not be related to abstraction; or indirectly, by reference to the RIVPACS data-base to assess the conservation interest of invertebrate assemblages.
1. Smaller members (< 10 mm) of the sediment-surface macrobenthos of Nanozostera capensis meadows across 9 km(2) of the marine Outer Basin of the Knysna estuarine bay (Garden Route National Park, Western Cape, South Africa) were investigated at a series of 24 stations. 2. Ordination (nMDS) disclosed the existence of five clusters of stations related to degree of exposure. Relatively sheltered stations were dominated by two endemic species of deposit-feeding microgastropod, and they supported significantly higher macrobenthic densities but lower species diversity and less evenness than relatively exposed stations. The latter were dominated by polychaetes and also possessed more suspension feeders, equivalent to more open seagrass beds in other latitudes. Species richness per station, however, was relatively constant across the whole basin. 3. The smaller benthic macrofauna, totalling 82 species, was found to include several animals (< 5 mm) hitherto unknown from the region, including one gastropod genus (Cornirostra) not previously known from Africa. 4. Species were patchily distributed across all scales from 1 m to > 1 km, but variance partitioning showed components of total variance to decrease with increasing spatial scale: sample (46.5%), station (30.0%), site (23.5%). 5. These findings are discussed in relation to conservation site selection in rich but faunistically heterogeneous seagrass beds that are impacted by bait collection or other human disturbance. Copyright (C) 2010 John Wiley & Sons, Ltd.
1.Hardbottom habitats of Biscayne Bay, a shallow lagoon adjacent to the city of Miami, Florida, USA, contain a limited number of coral species that represent a small subset of the species found at nearby offshore hardbottom and reef habitats of the Florida Reef Tract. Although the physical characteristics of this basin make it a marginal environment for coral growth, the presence of dense populations of Siderastrea radians and Porites furcata indicate that these, as well as other corals that are found at lower densities, are able to tolerate extreme and fluctuating conditions. Three factors, temperature, sedimentation, and salinity, appear to limit coral abundance, diversity, and distribution within Biscayne Bay.2.Temperatures exhibit high frequencies of extreme high and low values known to cause coral stress and mortality elsewhere. Similarly, sedimentation rates are very high and sediment resuspension caused by currents, storms and boating activities commonly bury corals under sediment layers. Sediment burial was shown experimentally to influence growth and mortality of S. radians.3.The salinity of Biscayne Bay is influenced by freshwater inputs from canal, sheetflow and groundwater sources that create a near-shore environment with low mean salinity and high salinity fluctuation. Coral communities along this western margin have the lowest coral density and species richness. Chronic exposure to low salinity was shown experimentally to cause a decrease in the growth of S. radians.4.The location of Biscayne Bay, downstream of a large restoration effort planned for the Everglades watershed, highlights the need to understand the relationship between the physical environment and the health of benthic communities. The data presented here provide the type of scientific information needed so that management decisions can take into account the potential impacts of human activities on the health of coral populations that are already near their tolerance limits for temperature, salinity, and sedimentation. Copyright © 2003 John Wiley & Sons, Ltd.
1.Diving surveys were undertaken to investigate the effects of marine reserve protection on spiny lobster (Jasus edwardsii) populations at Tonga Island Marine Reserve, northern South Island, New Zealand over a 2 year period from December 1998 to December 2000.2.Spiny lobsters were 2.8 times more abundant overall, and mean size was 19 mm carapace length larger in shallow transects and 28 mm carapace length larger in deep transects, in the marine reserve than at adjacent fished sites. That pattern was evident despite very high variability within sites, and among sites within reserve and fished areas.3.Large reproductive males were 10 times more abundant within the reserve compared to adjacent fished areas, suggesting that more eggs would be fertilized in the reserve than on the adjacent fished coast.4.Estimates of size-specific fecundity, combined with abundances of females, suggested that almost nine times more eggs would be produced in the reserve than in fished areas.6.We estimate that the mean abundance of spiny lobster in the reserve has increased by 22%, 5 years after its establishment, indicating an annual population increase of 4.4%. Over the same period, abundance of spiny lobster outside the reserve has declined by 2.9% per annum.7.Based on known spiny lobster movements, we suggest that marine reserves of more than 10 km length should be given priority over smaller reserves. Smaller reserves will, however, protect part of the population for at least a portion of their lifespan.8.Previous studies of movement of J. edwardsii suggest that spillover from the reserve should occur, and as population density increases we predict that more spiny lobsters will move out from the reserve. Copyright © 2002 John Wiley & Sons, Ltd.
The Amvrakikos Gulf and surrounding eastern Ionian Sea coastal waters with the bathymetry and the locations cited in the text. (1) The black triangle shows the position where eight bottlenose dolphins were individually identified in 2003. (2) East of the dashed line 85 bottlenose dolphins were individually identified between 1993 and 2004 (see ‘Discussion’). 
Survey coverage ‘on effort’ in years 2003–2005. 
Number of dorsal fins photographs obtained in years 2002-2005 following selection
Residency pattern of 106 marked individuals in the Amvrakikos Gulf. Black and grey cells indicate presence documented through digital photo-identification and transparencies, respectively; ‘ID’ (001–106) are the individuals identified; ‘ID#’ indicates the number of individuals encountered in each month of the study; ‘days’ is the number of days with photo-identification effort in a given month. 
1) Boat surveys were conducted between 2002 and 2005 to study bottlenose dolphins living in the 400 km2 Amvrakikos Gulf, western Greece. During 116 survey days, 4705 km of total effort resulted in the individual photo-identification of 106 animals, through long-term natural markings on their dorsal fins. 2) Mark–recapture analyses based on the Mth model provided estimates of 82 marked individuals in 2003 (95% CI=80–91), 92 in 2004 (95% CI=86–108) and 98 in 2005 (95% CI=94–110). To include the unmarked portion of the population, the proportion of unmarked individuals was computed based on the number of photographs of marked and unmarked dorsal fins. The mean proportion of unmarked animals in the population was 0.338 (95% CI=0.288–0.389). By adding this to the estimate for marked animals in 2005, considered as the most robust, a total population estimate of 148 individuals (95% CI=132–180) was obtained. 3) Dolphin encounter rates in 2003–2005 did not show significant variations, and averaged 7.2 groups per 100 km or 72.5 individuals per 100 km. Encounter rates within the Gulf were about one order of magnitude greater than those found for bottlenose dolphins in nearby eastern Ionian Sea coastal waters. 4) Mean dolphin density in the Gulf was 0.37 animals km−2. This relatively high density, together with high levels of site fidelity shown by most individuals, was thought to be related primarily to prey availability, particularly of epipelagic schooling fish. 5) The importance of the semi-closed Amvrakikos Gulf for bottlenose dolphins and other threatened species encourages the adoption of measures aimed to conserve its valuable ecosystems and raise the naturalistic profile of the area, while promoting environment-conscious development. Meaningful action includes restoring natural hydrology (e.g. freshwater input from rivers), curtailing pollution from various sources, responsible fisheries and aquaculture management, and control of illegal fishing. Interactions between dolphins and fisheries also deserve careful quantitative investigation.
1.Trammel nets are one important cause of sea turtle mortality resulting from incidental capture. This study presents findings over a 10-year period during which loggerhead turtle by-catch in trammel nets, set off the central west coast of Sardinia (Italy) in the summer months, was recorded by 17 fishing vessels.2.Since the by-catch registered represented counts of a rare event, data from the 17 vessels were used in the zero-inflated Poisson (ZIP) model to determine the abundance of turtle by-catch in trammel nets of the entire fleet, while a binomial generalized linear model was used to assess the probability of immediate survival for sea turtles incidentally caught in this gear.3.The ZIP model quantified in about 45% the probability that 0.6 turtles have been caught by each vessel using trammel nets during summer over the 10-year period. In addition, the model estimated a total of 916 by-catch if the entire small-scale fleet was to use trammel nets in the study area in the summers between 1992 and 2001, with a direct mortality rate of 69%.4.The probability of immediate survival for sea turtles caught in trammel nets seems to be directly related to the size of the specimens caught; however, this relationship is plausible only when incidental capture in the net occurs shortly before gear retrieval.5.The study area represents a region where the abundance of sea turtle by-catch per vessel in trammel nets was much higher in July and August than in June and could represent a potential hot spot for the presence of juvenile loggerhead turtles, with high levels of interactions between the species and this fishing gear. Further research should better characterize the incidents of by-catch and assess potential innovative solutions that allow small-scale fisheries to coexist alongside sea turtles. Copyright © 2010 John Wiley & Sons, Ltd.
1.Many rivers and streams across the world have been channelized for various purposes. Channel cross-sections of meandering rivers are asymmetrical and have cross-sectional diversity in their physical environment; cross-sections of a channelized river are typically trapezoidal and have little cross-sectional diversity, both in physical and ecological conditions. Several programmes to restore stream meanders have been undertaken to improve river ecosystems degraded by channelization. However, the association between diversification in the physical environment due to meander restoration and the macroinvertebrate community structure is poorly known.2.This study of a lowland river in Japan assessed how the cross-sectional diversity of the physical environment changed with restoration of a meander in a channelized river, and how the macroinvertebrate communities responded to the changes in physical habitat variation. Comparisons were made between the macroinvertebrate communities of a channelized reach, the restored meandering reach, and a natural meandering reach.3.Natural meandering and restored meandering reaches showed higher cross-sectional diversity in physical variables and total taxon richness across a reach than did the channelized reach. Almost all taxa observed in the natural and restored meandering reaches were concentrated in the shallowest marginal habitats near the banks. Shear velocity increasing with water depth had a negative association with macroinvertebrate density and richness.4.This study demonstrated that the shallow river bed along the inside of bends formed point bars that provided a highly stable substrate, a suitable habitat for macroinvertebrates in a lowland river. It is concluded that meander restoration could be an effective strategy for in-stream habitat restoration in lowland meandering rivers. Copyright © 2007 John Wiley & Sons, Ltd.
1.Closure of the Taff/Ely Estuary by the Cardiff Bay barrage in 1999 resulted in the replacement of intertidal mudflats by a permanent freshwater lake. This led to an 89% reduction in the population of shelducks Tadorna tadorna.2.The birds switched from foraging mainly for Nereis diversicolor and Hydrobia ulvae by scything with the bill as they walked across the mudflats at low tide, to feeding on benthic chironomid midge larvae while swimming in shallow water around the margins of the lake.3.The population decline occurred as a consequence of a decrease in the area available for foraging — from about 1 km2 of mudflats to about 0.1 km2 of water shallow enough for shelducks to reach the bottom when dabbling, head dipping and upending.4.Contrary to expectation, the amount of time shelducks spent feeding was similar pre- and post-barrage, and their body and plumage condition improved.5.A tidal rhythm in activity persisted, with a reduced amount of feeding at high tide, probably because of the slight rise in water levels that sometimes occurred at this time. Copyright © 2008 John Wiley & Sons, Ltd.
The Pelagos Sanctuary is the largest marine protected area of the Mediterranean Sea (87 500 km2), and is located in the north-west part of the basin. The presence of the bottlenose dolphin in this area is well documented but its distribution and abundance are not well known.The present study collected and analysed data from 10 different research groups operating in the Pelagos Sanctuary from 1994 to 2007. Photo-identification data were used to analyse the displacement behaviour of the dolphins and to estimate their abundance through mark–recapture modelling.Results show that the distribution of bottlenose dolphin is confined to the continental shelf within the 200 m isobath, with a preference for shallow waters of less than 100 m depth.Bottlenose dolphins seem to be more densely present in the eastern part of the sanctuary and along the north-west coast of Corsica.Bottlenose dolphins show a residential attitude with excursions usually within a distance of 80 km (50 km on average). A few dolphins exhibit more wide-ranging journeys, travelling up to 427 km between sub-areas.The displacement analysis identified two (sub)populations of bottlenose dolphins, one centred on the eastern part of the sanctuary and the other one around the west coast of Corsica.In 2006, the eastern (sub)population was estimated to comprise 510–552 individuals, while 368–429 individuals were estimated in the Corsican (sub)population. It was estimated that in total, 884–1023 bottlenose dolphins were living in the Pelagos Sanctuary MPA in the same year.The designation of a number of Special Areas of Conservation (SACs) under the Habitats Directive is discussed as a possible tool to protect the bottlenose dolphin in the Pelagos Sanctuary and in the whole of the Mediterranean Sea. Copyright © 2011 John Wiley & Sons, Ltd.
Coefficient of variation (CV; the ratio of standard error to arithmetic mean) in mussel density as a result of sampling from progressively more 0.5 Â 0.5 m quadrats. Mean CVs are calculated from sampling within four different UK lowland rivers. The dotted line indicates the point at which CV ¼ 0:2; Elliott (1971) suggests that an acceptable level of error in benthic samples is where CV40.2. 
1.Indicator taxa are widely used as a valuable tool in the assessment of freshwater biodiversity. However, this approach to identifying sites of conservation priority requires surveyors to possess expert taxonomic knowledge. Furthermore, sorting and microscopic examination of material can present logistical and financial constraints.2.Comparisons were made between the taxon richness and the density of freshwater mussels (Bivalvia: Unionidae) from 30 sites in seven UK lowland rivers, ranging from ca 3 m to 50 m width and ca 0.5 m to 4 m depth. Where mussels occurred, taxon richness of other invertebrates was strongly correlated with both mussel density and mussel biomass. Overall mussel density was a better predictor of taxon richness than the density of any individual mussel species.3.It is suggested that this association arises from the ‘keystone’ role that mussels play in many freshwater ecosystems. Local biota can benefit from the mussels' filtration, excretion, biodeposition and physical presence.4.Using mussel abundance as a surrogate provides a rapid and straightforward alternative to conventional methods of assessing freshwater biodiversity. No expert knowledge is required and any standardized sampling technique can be used. Freshwater mussels are found throughout the world's lentic and lotic fresh waters and this approach therefore has the potential for widespread utility, especially where rapid comparisons of biodiversity are required between biogeographically similar regions. In addition, the results highlight the ecosystem-level consequences of allowing the global decline of freshwater mussels to remain unchecked.Copyright © 2007 John Wiley & Sons, Ltd.
1.An abundance gradient from high inside to low outside a no-take marine reserve may indicate net emigration of adult fish from the reserve (‘spillover’).2.We examined spatial patterns of abundance of fish across two ∼900 m long sections of coral reef slope at each of two small Philippine islands (Apo and Balicasag). One section sampled the entire length of a no-take reserve and extended 200–400 m outside the two lateral reserve boundaries. The other section, without a reserve, was a control. The reserves had had 20 (Apo) and 15 (Balicasag) years of protection when sampled in 2002.3.Significant spatial gradients of decreasing abundance of target fish occurred across only one (Apo Reserve northern boundary = ARNB) of four real reserve boundaries, and across none of the control ‘boundaries’. Abundance of non-target fish did not decline significantly across reserve boundaries.4.Abundance of target fish declined sharply 50 m outside the ARNB, but enhanced abundance extended 100–350 m beyond this boundary, depending on fish mobility.5.Density of sedentary target fish declined 2–6 times faster than density of highly vagile and vagile target fish across the ARNB.6.Habitat factors could not account for these ARNB results for target fish, but did influence abundance patterns of non-target fish.7.The lack of abundance gradients of target fish at Balicasag may reflect reduced fishing outside the reserve since it was established.8.Apo Reserve had a gradient of abundance of target fish across at least one boundary, a result consistent with spillover. Copyright © 2006 John Wiley & Sons, Ltd.
1.Five side-channels and small tributaries of the River Avon (Hampshire, UK) were examined between spring 1999 and spring 2000 using point abundance sampling by electrofishing to determine the status of fish listed in Annex II of the EC Habitats Directive prior to habitat management works to enhance spring feeding habitat of wading birds.2.Seasonal patterns of abundance and microhabitat use of bullhead Cottus gobio and accompanying fish species were examined. Parr of Atlantic salmon Salmo salar were sufficiently abundant for microhabitat analysis at one site only. Only two specimens of brook lamprey Lampetra fluviatilis were observed, one at each of two sites. Bullhead was amongst the most abundant fish species at all five sites, 0+ bullhead predominating.3.Bullhead microhabitat preferences were generally similar at all five sites, but seasonal variations were observed, as was the case for the accompanying fish species, which included dace Leuciscus leuciscus, chub Leuciscus cephalus, stone loach Barbatula barbatula, roach Rutilus rutilus, and threespine stickleback Gasterosteus aculeatus.4.Bullhead conservation status is discussed, in particular the possible exemption of British bullhead populations, such as already granted for those of Finland, from Annex II of the Habitats Directive. © Crown Copyright 2004 Reproduced with the permission of Her Majesty's Stationary Office. Published by John Wiley & Sons, Ltd.
Freshwater mussel species diversity in seven reaches of the Sipsey River, Alabama. Reaches are numbered in longitudinal order from downstream (reach I) to upstream (reach VII).
Length–frequency histograms for three mussel species in the Sipsey River Alabama in 2000. Data are composites across sites 1, 3, 5, and 6 (see text).
Estimated bivalve population size (95% confidence intervals) at four sites in the Sipsey River, Alabama in 2000
1.Patterns of mussel diversity and assemblage structure in the Sipsey River, Alabama, are described. Qualitative data were used to describe river-wide patterns of diversity. Quantitative data were used to describe the structure of mussel assemblages at several sites based on whole-substrate sampling that ensured all size classes were detected.2.Major human impacts to the stream are limited to apparent effects of coal mining in the headwaters and the impoundment of the lower 9 km of the river by a dam on the Tombigbee River. These impacts resulted in a sharp decline in mussel diversity in the headwaters, and extirpation or decline of populations of several large-river species in the lower river that were probably dependent on colonization from the Tombigbee River.3.Despite localized impacts, mussel assemblages throughout much of the river appear to be mostly intact and self-sustaining. These assemblages have several attributes that differ substantially from those in more degraded streams: (1) high retention of historical species richness; (2) gradual, longitudinal increase in species richness from upstream to downstream, resulting in distinctive headwater and downstream assemblages; (3) ubiquity of most species within particular river segments; (4) low dominance and high evenness with large populations of many species; and (5) frequent recruitment for most species resulting in occurrence of individuals in many size classes.4.Few detailed and demographically unbiased descriptions of relatively intact mussel assemblages exist. We propose that characteristics described in the Sipsey River can be used as a baseline comparison for assessing relative degree of assemblage alteration in other streams and can serve as goals for restoration efforts. Published in 2010 by John Wiley and Sons, Ltd.
1. This paper is focused on the identification of patterns of variation in phytoplankton abundance and taxonomic composition at the eco-regional scale. In addition, these patterns were evaluated with respect to climatic, hydrological and physiographic drivers.2. A hierarchical sampling design was used to integrate seasonal and spatial variations in taxonomic richness, abundance and taxonomic composition of phytoplankton guilds. Data were collected synoptically during two seasons (autumn and spring) in 12 transitional water bodies in Italy, Albania and Greece.3. The number of taxa and the cell density of phytoplankton guilds varied between seasons and across ecosystems. Overall, physiographic and hydrological components accounted for 61% of the variation in the number of taxa, but just 19% of the variation in cell density.4. At the univariate level, cell density varied significantly with temperature, whereas the number of taxa was found to vary significantly with depth, sinuosity index and outlet structure, lagoon surface area and geographic location.5. The taxonomic composition of phytoplankton guilds varied markedly among lagoons. More than 61% of the 242 taxa identified overall were detected in only one of the lagoons.6. The average similarity of phytoplankton taxonomic structure among ecosystems was 33.15 ± 15.02. Taxonomic similarity varied substantially across both ecosystems and seasons. Overall, more than 70% of variance in taxonomic similarity was explained by physiographic and hydrological forcing factors. Specifically, differences in taxonomic structure were found in transitional ecosystems showing differences in outlet structure, depth and salinity, as well as geographic location. A recurrent pattern of decreasing taxonomic similarity with increasing Euclidean distance was observed for each factor.7. The results obtained in this study suggest that certain large-scale driving forces can explain eco-regional scale patterns of species richness and taxonomic composition but not of cell abundance, which are probably more affected by local forcing factors. Copyright © 2008 John Wiley & Sons, Ltd.
An example of results from the validation exercise. Coral data generated from a maximum sample size of 48 (8 reef sites and 6 survey groups per site) at South Water Cay, Belize, February 1993. Actual sample size for each species shown in parentheses. Source, Mumby et al., 1995.
1. This paper describes a straightforward method for introducing species weightings into the calculation of a similarity matrix using the Bray–Curtis coefficient. Weighting may be required in order to provide differential emphasis in abundances on the basis of species' size, ecological importance, abundance or in mixing different data types. The similarity matrix can then be used for a range of multivariate analytical procedures, such as cluster analysis or ordination using non-metric multi-dimensional scaling (MDS). Such techniques are widely used for the identification of species' assemblages and habitats in marine resource and conservation assessment. 2. The weighting procedure was used to examine the effect of variable accuracy in species identification by trained volunteer divers conducting baseline surveys of reefal habitats in Belize. The accuracy of identification was found to vary asymmetrically between species. 3. The modified Bray–Curtis similarity coefficient was used to incorporate individual species weightings which are proportional to the frequency at which each species is correctly identified. The results of the study demonstrate the fundamental robustness of the Bray–Curtis similarity coefficient/multivariate approach which together, are insensitive to the asymmetric accuracy levels present in the data.
Marine mining of manganese nodules will affect the deep sea benthos in a harmful and longterm way. The near complete removal of manganese nodules will result in a change of the megabenthic community from one that is rich in both diversity and density to a soft bottom community with greatly reduced diversity.Pre-pilot mining tests and pilot mining operations, which have to demonstrate the feasibility of deep-sea mining, should be accompanied by environmental impact studies before commercial mining begins.The photographic assessment of megabenthic communities represents one cost-effective possibility of monitoring large-scale impacts on the deep sea floor. A method based on the analysis of video and photomaterial was used to obtain basic data on community structure and density of the abyssal megabenthos of undisturbed manganese nodule sites in the North (Clarion-Clipperton Fracture Zone) and South (Peru Basin) Pacific Ocean.A comparison of the results with data from the literature demonstrates that the different methods used result in different density values.Total density varied between less than 300 to more than 1600 individuals/10000 m2.There is a clear need for standardization of methods. A system which combines video and photographic capabilities is useful. It will give the best results when the distance of the camera to the sea floor is between 2 and 3 m, and the area covered by one photograph is within 3 to 5 m2.
1.In 2006, two periods of hypoxia resulted in the death of approximately 35 tonnes of black bream (Acanthopagrus butcheri) in Lake Indoon, a small inland lake in Western Australia.2.Acanthopagrus butcheri was the first fish species to be recorded in this lake, along with the mosquitofish (Gambusia holbrooki) which was also observed during sampling in 2006. Acanthopagrus butcheri appears to have been introduced to Lake Indoon between 1998 and 2003 and formed a self-sustaining population. It is believed to have been deliberately introduced for the purpose of creating a recreational fishery, despite the existence of substantial penalties for illegal translocation of fish in Western Australia.3.Recent human-induced environmental changes, including rising groundwater and salinization, have probably aided the establishment of both species in Lake Indoon. The importance of salinity to recruitment success by A. butcheri was indicated by the presence of only two age classes in 2006, with estimated recruitment dates coinciding with the years of highest recorded salinity in the lake.4.The ‘fish kills’ provided an opportunity to examine aspects of A. butcheri biology in a relatively low salinity environment which is atypical for this estuarine species. In particular, the recruitment period in Lake Indoon was delayed until autumn/winter, rather than spring/summer as seen in other populations. Biological responses in Lake Indoon have implications for natural populations living in estuaries with modified salinity regimes.5.The ecological, social and economic impacts potentially arising from the introduction of fish to Lake Indoon, which is an important migratory bird habitat and a recreational amenity for local residents and tourists, illustrate the complexities of fish translocation and the need for rigorous assessment before stocking to identify potential costs and benefits. Copyright © 2008 John Wiley & Sons, Ltd.
1.The effects of trampling by visitors walking over the reef flat to snorkel or swim along the reef edge were studied at Ras Um Sidd, a popular fringing reef site at Sharm El Sheikh, and in the Ras Mohammed National Park, South Sinai, Egypt. Twelve stations showed a sequence of events linked to increased frequency and extent of trampling, with the intensities of trampling ranging from 0.1 to 324 tramplers m−2 yr−1.2.Heavily trampled stations had a reduced coral cover (in particular branching corals), higher amounts of coral damage, less old dead coral, less obligate corallivorous fishes and more herbivores.3.Wave exposure was crucial in determining the susceptibility of coral communities to trampling. Exposed communities were dominated by branching corals and were mechanically more resistant, since wave stress had favoured stockier growth forms.4.The applicability of the ‘carrying capacity concept’ was investigated as a management tool for determining how much use is sustainable. Examination of the relationship between hard coral cover and intensity of trampling suggested that carrying capacity could be set at approximately 50 tramplers m−2 yr−1. The actual amount of damage caused by trampling showed a linear increase with increasing trampling intensities, so that the carrying capacity concept, as defined in this study, was not applicable to the relationship since no threshold existed. Instead, the ‘limits of acceptable change’ approach would be more practicable, with managers deciding what amount of coral damage they permit before limiting access. To establish meaningful limits of change, more knowledge is required about ecological as well as social consequences (e.g. visitor satisfaction) of such limits. Copyright © 2007 John Wiley & Sons, Ltd.
1.Knowledge about processes and dynamics underlying organic matter accumulation in transitional waters is crucial for the protection of these ecologically important coastal habitats. This study investigated the relationship between large particle accumulation and decomposition in a coastal lake included in a Site of Community Interest (SCI) using sediment trap and litterbag techniques.2.Two sets of sediment traps were deployed at five sites along the longitudinal axis of the lake. One set was emptied once a month for 12 months, and the other twice a year. The contents of the monthly and the 6-monthly traps and the superficial sediments were then compared to estimate the organic matter accumulation and loss. To determine the mass loss rate of the three major allochthonous sources of detritus (the reed Phragmites australis, the cordgrass Spartina juncea, and the seagrass Posidonia oceanica), litterbags were placed near the sediment traps at three out of the five sites at the beginning of each 6-month period and retrieved monthly.3.The amount of annual particulate organic matter (POM) deposition in the traps was 1320.2±58.5 g m−2 y−1 and consisted of 25% large particles (CPOM). Allochthonous litter comprised an important fraction of CPOM, and its breakdown rate changed with the plant species, site and season. Loss rate of CPOM accumulated at the lake bottom was significantly related with the mass loss rate of reed and cordgrass litter, but not with that of seagrass.4.Due to slow litter breakdown and tidal landward advection, the lake acted as a sediment trap for allochthonous matter, especially from Posidonia. The important role of marine-derived litter in organic matter sedimentation suggests addressing conservation strategies of the lake functioning towards the selective control of allochthonous CPOM inputs, in particular at the mouth where the incoming tide brings suspended material and salinity decelerates matter flow to the sea and decomposition. This study supports the hypothesis that sedimentation and decomposition dynamics are important factors for coastal lake evolution, and shows litterbag and sediment trap techniques as simple useful investigation tools in management strategies aiming at conserving transitional waters. Copyright © 2008 John Wiley & Sons, Ltd.
1.Accumulations of maerl occur widely in ocean facing coastal waters (<20–30 m depth) of the northeast Atlantic, that are sheltered from the direct SW approach of storm waves and have little terrigenous sediment supply.2.The different methods that have been used to assess the rate of formation of cool temperate, coralline algal gravels (maerl) are outlined.3.Formation rates of maerl may be expressed as short-term, branch growth rates (mm yr−1), as calcium carbonate production rates (g CaCO3 m−2 yr−1), or as longer-term accumulation rates (m kyr−1=m 1000 yr−1).4.Branch growth rates of the free living, branching coralline algae that form maerl in northwest Spain and western Ireland vary from 0.1 to 1.0 mm yr−1. Rates from Norway are either 0.05–0.15 or up to 1.0 mm yr−1.5.Production rates vary from 30–250 g CaCO3 m−2 yr−1 in western Ireland, 876 g CaCO3 m−2 yr−1 in northwest France and 90–143 or 895–1423 g CaCO3 m−2 yr−1 in Norway.6.Accumulation rates vary from 0.08 m ky−1 in Orkney to 0.5 m ky−1 in Cornwall, to 0.8–1.4 m kyr−1 in Norway.7.These production and accumulation rates are similar to the lower end of such rates from tropical coral reef environments. This is achieved by high standing crops that compensate for the lower growth rates of the temperate algae. Although rapid on a geological time-scale these accumulation rates are far too low for the maerl to be regarded as a sustainable resource for extraction for agricultural and industrial use. Copyright © 2003 John Wiley & Sons, Ltd.
1.Invasive species threaten marine biodiversity on a global scale.2.To test whether marine reserves provide resistance to invading species, the abundance of two conspicuous invaders, a seaweed and an oyster, were measured inside marine reserves and in comparable areas outside reserves in north-western Washington State.3.Densities of both invaders were significantly higher in marine reserves than in comparable unprotected areas outside reserves. Although the causal mechanisms have not yet been identified, differential rates of human harvest do not appear to be responsible for the patterns observed.4.It is provisionally suggested that physical or biological aspects of the reserves themselves may directly or indirectly facilitate biological invasion. Copyright © 2006 John Wiley & Sons, Ltd.
ABSTRACTA vast scientific literature has been devoted to identifying the best way to represent biodiversity for conservation in the last decade. Methods exist for deciding how to use scarce information and avoid omission and commission errors. The effect of these errors on reserve efficiency does not arise only from the accuracy of data representing conservation features, as usually considered. There are also several underlying assumptions associated with the type of data used that might affect accuracy of conservation decision-making and compromise achievement of conservation objectives.Here the effects of two management scenarios on selection of priority areas for conservation are explored. The spatial distribution of 10 native freshwater fish species in an Iberian basin under present-day and reference conditions were modelled and priority areas for both scenarios using the same spatial and cost constraints were identified.Priority areas identified under the present-day scenario reflected the up-to-date spatial distribution of species and avoided the selection of highly perturbed and costly areas. The isolated spatial distribution of native populations imposed by the current perturbation status limited the spatial connectivity between priority areas under the present-day scenario. Most importantly for the achievement of conservation objectives, priority areas selected under both scenarios did not overlap.Given that the reference scenario was based on potential presence of native species the actual representation of species would be overestimated if consideration were not given to restoring reference conditions (high commission errors). Based on results obtained it is recommended that planners give more consideration to the current perturbation status when identifying priority areas for conservation. Copyright © 2011 John Wiley & Sons, Ltd.
1.The ecological recovery of streams from large-scale perturbations, such as acidification, requires aquatic insects to disperse between catchments. While adults can usually fly, dispersal is seldom observed directly. Catches of insects in transects of traps perpendicular from streams suggest that lateral adult dispersal is limited. This paper evaluates whether this could explain limited biological recovery in streams recovering chemically from acidification.2.At the replicate Llyn Brianne experimental catchments (Wales), Malaise traps (2000) and benthic sampling (1985–2005) were used to appraise inter-catchment dispersal in acid-sensitive Ephemeroptera, Plecoptera and Trichoptera. The results provide direct evidence for inter-catchment dispersal: eight species from three Orders were caught as adults alongside acid streams where larvae never occurred in 21 years' benthic sampling.3.These data refute the hypothesis that limited dispersal per se explains delayed biological recovery from acidification in Welsh streams. Other factors affecting colonization (e.g. ‘propagule pressure’, mating or oviposition behaviour) and persistence (e.g. continued acid episodes) must be involved, with the first of these possibilities still poorly understood. These data add to a growing body of literature illustrating insect dispersal between catchments, and they have wider relevance to the recovery and restoration of river ecosystems following basin-scale impacts.Copyright © 2006 John Wiley & Sons, Ltd.
1.The Water Framework Directive (WFD) requires the assessment of acidification in sensitive water bodies. Chemical and littoral macroinvertebrate samples were collected to assess acidification of clear and humic lakes in the UK.2.Of three acid-sensitive metrics that were regressed against acid neutralizing capacity (ANC) and pH, highly significant responses were detected using the Lake Acidification Macroinvertebrate Metric (LAMM). This metric was used to assign high, good, moderate, poor and bad status classes, as required by the WFD.3.In clear-water lakes, macroinvertebrate changes with increasing acidification did not indicate any discontinuities, so a chemical model was used to define boundaries. In humic lakes, biological data were able to indicate a distinct, good–moderate boundary between classes.4.Humic lakes had significantly lower pH than clear lakes in the same class, not only at the good–moderate boundary where different methods were used to set boundaries, but also at the high–good boundary, where the same chemical modelling was used for both lake types. These findings support the hypothesis that toxic effects are reduced on waters rich in dissolved organic carbon (DOC).5.A typology is needed that splits humic and clear lakes to avoid naturally acidic lakes from being inappropriately labelled as acidified.6.Validation using data from independent lakes demonstrated that the LAMM is transportable, with predicted environmental quality ratios (EQRs) derived from mean observed ANC, accurately reflecting the observed EQR and final status class.7.Detecting and quantifying acidification is important for conservation, in the context of appropriate restoration, for example, by ensuring that naturally acid lakes are not treated as anthropogenically acidified. Copyright © 2009 John Wiley & Sons, Ltd and Crown Copyright 2009
Top-cited authors
Paul Dayton
  • University of California, San Diego
Tundi Agardy
  • Sound Seas
Nicholas K Dulvy
  • Simon Fraser University
Stephen J Hawkins
  • University of Southampton
Juergen Geist
  • Technische Universität München