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- 1. The identification and protection of known breeding grounds is a high priority for the conservation of marine biodiversity. Here, we examine the intertidal habitats used by marine gastropods for the deposition of benthic egg masses along a wave‐exposed coastline in New South Wales, Australia.
- 2. A total of 200 surveys were conducted on 13 intertidal reefs. The egg masses of 46 species were identified, with a further eight distinct types recorded but remaining unidentified. Over half of the gastropods were found to deposit egg masses exclusively on the underside of boulders. Other intertidal substrata used for gastropod egg mass deposition included vertical and horizontal exposed rock surfaces, algal fronds and sand. Only eight species were found to attach their egg masses to more than one type of substratum.
- 3. Twelve reefs were classified into three categories according to exposure to wave action and habitat diversity. The mean number of species found depositing egg masses was compared using a standard eight surveys from each site. Sub‐maximally wave‐exposed reefs with maximal habitat diversity were found to support a significantly higher species richness of gastropod egg masses, compared with maximally wave‐exposed reefs with either maximal or sub‐maximal habitat diversity (p=0.000).
- 4. Gastropods that deposit egg masses on the underside of boulders were more likely to be found on sub‐maximally wave‐exposed reefs, whereas species that deposit egg masses in all other microhabitats were equally likely to be found breeding on sub‐maximally or maximally exposed reefs.
- 5. Gastropods with pelagic larvae tended to occur at a greater number of sites than those that hatch post‐metamorphosis. A significant difference was found between species grouped according to these two developmental modes for the mean number of sites at which egg masses were recorded (p=0.008).
- 6. Variation in the species richness of gastropods found depositing egg masses on different intertidal reefs appears to be influenced by the availability of suitable boulders and exposure to wave action. These factors should be taken into consideration during the selection of locations for intertidal protected areas.
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Carlos A. Moreno 《水产资源保护:海洋与淡水生态系统》2001,11(1):19-30
1. The Chilean rocky coast has been exploited for food by coastal gatherers for at least 8500 years BP and probably was an important factor in how prehistoric people were able to colonize the South Americas Pacific Rim. The main species targeted in the past were the same as those today except that now the gatherers are resident and the fishing activity is more intense and persistent. 2. With many pertinent studies from around the world having been published on this topic, mostly conducted in Marine Reserves, this review tries to identify the main patterns that can help us recognize, in the Chilean intertidal, the degree of exploitation on wave exposed and wave protected rocky shore habitats. 3. Three clear patterns were identified depending on the trophic level adopted by the human gatherers in the food chain of the intertidal zone. First, when the humans act as herbivores, collecting the large laminarian Durvillaea antarctica, adult plants disappear from the accessible sites, especially the midlittoral, semi‐exposed and exposed habitats. 4. Second, when humans harvest the ecologically important herbivorous archeogastropoda Fissurella spp., this results in the red alga Mazzaella laminarioides covering almost 100% of the midlittoral rocks. Third, when humans become top predators by collecting the muricid carnivore Concholepas concholepas, then bivalves, mainly Perumytilus purpuratus, cover the rocks in multiple layers. 5. These patterns contribute to the evaluation of the state of conservation of the Chilean rocky intertidal shores, especially because the north and the south are beginning to be connected by a new coastal road. Thus it is necessary to evaluate urgently, on a large spatial scale, the state of conservation of these communities, in order to help select the appropriate places for establishing Marine Reserves. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
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Timothy D. O'hara Prue F. E. Addison Ruth Gazzard Trudy L. Costa Jacqueline B. Pocklington 《水产资源保护:海洋与淡水生态系统》2010,20(4):452-463
- 1. Conservation managers require biodiversity assessment tools to estimate the impact of human activities on biodiversity and to prioritize resources for habitat protection or restoration. Large‐scale programs have been developed for freshwater ecosystems which grade sites by comparing measured versus expected species richness. These models have been applied successfully to habitats that suffer from systemic pressures, such as poor water quality. However, pressures in other habitats, such as rocky intertidal shores, are known to induce more subtle changes in community composition.
- 2. This paper tests a biodiversity assessment methodology that uses the ANOSIM R statistic to quantify the biological dissimilarity between a site being assessed and a series of reference sites selected on the basis of their similar environmental profile. Sites with high R values for assemblage composition have an anomalous assemblage for their environmental profile and are potentially disturbed.
- 3. This methodology successfully identified moderate to heavily perturbed sites in a pilot study on 65 rocky intertidal sites in south‐eastern Australia. In general, measures based on percentage cover (flora and sessile invertebrates) were more sensitive than abundance (fauna). Copyright © 2010 John Wiley & Sons, Ltd.
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Cristina Trigal‐Domínguez Camino Fernández‐Aláez Francisco García‐Criado 《水产资源保护:海洋与淡水生态系统》2009,19(7):786-796
- 1. Habitat heterogeneity has many implications in ecological assessment studies. On one hand it provides varying niches for organisms, increasing diversity. On the other hand, the inherent spatial variability of structurally complex systems may overlap with ecological condition making it difficult to disentangle the effects of perturbation. This study investigated the combined and single effects of habitat and pond condition on the macroinvertebrate assemblages of 35 ponds located in north‐west Spain and spanning a range of water quality and habitat characteristics.
- 2. Macroinvertebrate communities and several environmental variables were sampled in the summer of 2004 or 2003. Samples were collected from four dominant habitats (vegetated shores, shores without vegetation, submerged vegetation, bare sediments) following a time‐limited sampling. Non‐metric multidimensional scaling and two‐way crossed ANOSIM were used to investigate the taxonomic and functional differences in macroinvertebrate assemblage structure among habitats (four types) and pond conditions (optimal, good, moderate, poor, very poor). To investigate the individual and combined effects of pond condition and habitat on several diversity measures GLM models were used. In addition, the accuracy of two sampling designs — stratified and multihabitat — was compared using the CVs of seven macroinvertebrate attributes.
- 3. Results showed that macroinvertebrate communities differed significantly, albeit weakly, among habitat types and pond condition categories. In particular, the abundance of several Chironomidae genera, rarefied richness and Shannon index decreased both in perturbed systems and bare sediments, whereas no marked differences occurred between shores and submerged vegetation.
- 4. We suggest that a multihabitat approach together with the use of community attributes not (or slightly) affected by habitat type will provide more comparable results across ponds than a stratified approach or observation of the whole community, especially in ponds where degradation leads to habitat loss.Copyright © 2009 John Wiley & Sons, Ltd.
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Xiaoyong Xie Zhou Wu Chun‐Chieh Wang Yijian Fu Xueping Wang Peng Xu Xing Huang Yongyan Liao Shiang‐Lin Huang Kit Yue Kwan 《水产资源保护:海洋与淡水生态系统》2020,30(2):260-272
- Identification, protection and enhancement of essential habitats are priority issues for management and restoration of exploited species. The shores utilized by Asian horseshoe crabs as nurseries were surveyed and the coastal habitat characteristics were described in the northern Beibu Gulf of China. Regression models were applied to explore species‐habitat relationships.
- Fourteen and ten nursery sites were identified for Tachypleus tridentatus and Carcinoscorpius rotundicauda populations, respectively. Xiacun and Jinhaiwan in the eastern region of the northern Beibu Gulf were the essential nurseries for T. tridentatus, whereas Shanxin and Jiaodong in the western part were the primary nursery shores for C. rotundicauda. These shores supported high densities (4–6 individuals/100 m2) of juvenile horseshoe crab populations.
- Mangrove and seagrass coverage area, coupled with sediment physico‐chemical parameters, particularly grain size, and the environmental heterogeneity of nursery habitats explained the distribution pattern of juvenile populations. Most juvenile populations were found along the outer fringe of mangroves in the small shallow estuary, particularly near outflows of tidal creeks with generally higher chlorophyll a and organic carbon contents. The distribution of high‐density juvenile populations of both species also overlapped with areas of seagrass patches.
- These findings highlight the importance of mangroves and seagrasses in the nursery habitat use of Asian horseshoe crabs. Preserving the estuarine habitats with these vegetation types and identifying the high‐use nursery sites should be prioritised in China and other Asian places to conserve the declining Asian horseshoe crab populations.
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Andrea Pulfrich Colleen A. Parkins George M. Branch Rodrigo H. Bustamante Claudio R. Velsquez 《水产资源保护:海洋与淡水生态系统》2003,13(3):257-278
- 1. Extensive diamond mining occurs on land and in the sea on the west coasts of South Africa and Namibia, raising fears that diamond‐mining activities may impact commercial rock‐lobster fisheries and benthic communities. To explore this possibility, the effects of the diamond‐mining fines‐discharge on intertidal and subtidal rocky‐shore communities and on the population structure of the rock lobster Jasus lalandii were assessed at Elizabeth Bay.
- 2. Sampling over six years at sites covering a range of wave exposures compared impacted sites with comparable reference sites never exposed to the fines. Percentage cover and densities of benthic organisms were recorded on both intertidal and subtidal reefs. Rock‐lobster abundance was estimated from counts and catch‐per‐unit‐effort, and their length frequencies and sex ratios compared in impacted and reference areas.
- 3. The deposition of fines had no effect at wave‐exposed sites, but did impact intertidal and subtidal communities at sheltered localities where fines accumulated because wave action was insufficient to disperse them. Reductions of grazers, proliferation of algae and increased dominance by filter‐feeders were recorded at the impacted sites and persisted throughout the monitoring programme. Differences in community structure associated with different levels of wave exposure were, however, greater than those produced by depositing fines. The detected effects of fines‐deposits on the benthos were local and likely to be reversible after cessation of mining.
- 4. The fines‐deposit had no detectable effects on the sex‐ratio, size or abundance of rock lobsters, indicating that there is no conflict between the deposition of fines and the fishery for rock lobsters, although substantial inter‐site variability makes it difficult to regard the results as definitive.
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- Habitat loss and degradation together represent one of the five major factors contributing to the rapid decline of the Yangtze finless porpoise in the Yangtze River. Protecting key habitat patches and maintaining migration corridors between habitat patches are major conservation objectives to ensure the in situ viability of the Yangtze finless porpoise. Baseline information essential for addressing these two objectives includes that pertaining to distribution and habitat preference.
- To investigate the distribution and habitat preferences of the Yangtze finless porpoise, five transect surveys were conducted in the Anqing section of the Yangtze River, which has the highest porpoise density among all sections of the river. Porpoise abundance estimates were calculated, and preferences for different habitat types were evaluated.
- The calculated porpoise abundance in the Anqing section was 181 (95% CI 125–239) animals on average. The inter‐annual and inter‐seasonal differences in porpoise abundance estimates were not significant. The natural river banks and sandbar shores were the most preferred habitats, representing 46.3 and 29.8% of the porpoise observations, respectively. In contrast, 8.1% of the porpoises were observed in habitats along reinforced river banks, which account for 38.7% of the total coastline. In subsections with natural habitat patches, porpoises were observed in almost every survey, while porpoise occurrence became highly stochastic in subsections with long reinforced river banks. These results indicate a significant tendency of the Yangtze finless porpoise to prefer natural habitats with natural river bank or sandbars but to keep away from reinforced river‐bank habitats.
- According to porpoise density in different subsections, free migration may be impeded or only one migration corridor remains in some subsections.
- Although protecting finless porpoise habitats has become a primary conservation objective, this study highlights the need to protect frequently used habitat patches and migration corridors, particularly those near natural river banks and sandbars, and to restore ecological environments along reinforced river banks.
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Status of galaxiid fishes in Tasmania,Australia: conservation listings,threats and management issues
Scott A. Hardie Jean E. Jackson Leon A. Barmuta Robert W.G. White 《水产资源保护:海洋与淡水生态系统》2006,16(3):235-250
- 1. Fish of the family Galaxiidae are restricted to the southern hemisphere where they occupy a diverse array of habitats ranging from over 2000 m in elevation to sea level. Some species are diadromous and, hence, freshwater, estuarine and marine habitats are used during their life‐cycle; other species complete their entire life‐cycles in freshwater environments.
- 2. Tasmania has a diverse galaxiid fauna that accounts for 64% of native freshwater fish species found on the island. The Tasmanian galaxiid fauna is characterized by high species richness (5 genera and 16 species), endemism (11 species), restricted distributions, and non‐diadromous life histories (11 species).
- 3. The galaxiid fauna of Tasmania has significant conservation status with 69% of species considered ‘threatened’. The conservation status of the fauna is recognized at State, national and international levels.
- 4. The key threats to galaxiids in Tasmania are exotic species, hydrological manipulations, restricted distributions, general habitat degradation and exploitation of stocks.
- 5. Although work has recently been undertaken to conserve and manage Tasmanian galaxiid populations, the fauna is still thought to be imperilled. Knowledge gaps that need to be addressed include the biology and ecology of most species (e.g. reproductive biology, life histories, habitat use and requirements) and impacts of habitat manipulations, as well as mechanisms and impacts of interactions with exotic species. Techniques to monitor accurately the status of galaxiid species and their populations need to be developed and the coexistence of some galaxiids with introduced salmonids should also be examined.
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David A. Schumann Katie N. B. Graeb Jarrett Pfrimmer Joshua D. Stafford Steven R. Chipps 《水产资源保护:海洋与淡水生态系统》2021,31(9):2481-2495
- Landscape homogenization and the removal of riparian areas have altered stream ecosystems worldwide. Numerous conservation programmes attempt to improve water quality and increase instream habitat heterogeneity to elicit desired biological responses. However, the effectiveness of many conservation efforts on isolated stream fragments remains unknown, especially in grassland regions.
- The effects of grassland conservation practices and the re-establishment of riparian corridors in the James River basin, South Dakota (USA) on stream water quality, habitat availability and aquatic macroinvertebrate and fish assemblages were studied in an agriculturally dominated prairie landscape.
- Grassland conservation efforts may have repaired riparian condition, reduced turbidity and created more diverse instream habitat complexes at conservation sites based on comparisons with paired reference reaches. Reference sites were relatively homogeneous, with prevalent siltation, bank erosion and disturbances to the riparian vegetation. Owing to significant riparian vegetation development, overhanging and aquatic vegetation, benthic detritus and woody materials were significantly more common at conservation reaches.
- Restoration efforts that assume ‘if you (re-)build it, they will come’ (i.e. the ‘field of dreams’ hypothesis) underestimate other important barriers to biodiversity restoration in dynamic, grassland riverscapes. Although aquatic organisms in grassland ecosystems are adapted to rapidly inhabit available habitats, the development of niche space at conservation reaches did not directly result in colonization by aquatic life.
- Grassland management actions did not address stream connectivity issues or overcome land use influences elsewhere in the riverscape that may govern the responses of aquatic macroinvertebrates and fish. Stream fragmentation and continuing, damaging land use patterns seemed to exceed the positive effects of restoring isolated stream reaches in these heavily degraded catchments. Catchment-scale management strategies that combine reach-level restoration actions with efforts to improve connectivity are likely to be more successful in degraded riverscapes.