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. 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. 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. 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. 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.
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. 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) 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.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 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.