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1.
Coastal ecosystems are complex and species rich, but are vulnerable to degradation from a variety of anthropogenic activities. Nevertheless, information on inter‐tidal community composition in the Caribbean Basin and at other oceanic sites is lacking. Such information is essential to developing a more comprehensive understanding of rocky inter‐tidal systems and their responses to global change. The goals of this study were to determine the relative importance of environmental (wave power density, wave height), habitat (e.g. algal cover, slope, complexity of rock surfaces) and anthropogenic (distance to roads, population density) factors associated with the structure of local assemblages at multiple shore heights and the regional metacommunity of mobile invertebrates on oceanic rocky inter‐tidal habitats. Environmental characteristics associated with habitat complexity (algal cover, rock surface complexity) and human population density were most strongly associated with abundance and biodiversity of invertebrates. Species richness was positively correlated with surface complexity, but abundance was negatively correlated with both surface complexity and per cent algal cover. By contrast, abundance of invertebrates was positively correlated with human population density, and diversity was negatively correlated with human population density. Abundance of invertebrates was greatest in the mid inter‐tidal zone, whereas diversity was greatest in the lower inter‐tidal zone. Metacommunity structure was Gleasonian, but the gradient along which species turnover occurred was correlated with measures of wave exposure, rather than anthropogenic activity. Unlike in previous studies, mostly at mainland sites, human activity primarily altered dominance patterns of communities, while having relatively little effect on species richness or composition.  相似文献   

2.
The rocky inter‐tidal habitat is a harsh and fluctuating environment, subject to frequent disturbances. Field observations of juvenile white seabream Diplodus sargus in inter‐tidal rocky habitats were conducted to analyse the spatial distribution and feeding activity of this species in relation to the tidal cycle. The depth at which fish were observed did not change in most tidal phases while feeding activity changed with tidal level, showing the occurrence of tidal migrations and that feeding may be limited by habitat availability in shallow waters and thus be dependent on tidal changes. The present results show the exploitation of available feeding areas in the rocky inter‐tidal by juvenile white seabream, which corroborates the importance of these habitats for the first developmental stages of this fish species.  相似文献   

3.
Tidal conditions differently influence inter‐tidal organisms in terms of general physiological and metabolic responses. In this study we investigated the morphological response in shells of Mytilus galloprovincialis native to different micro‐tidal coastal environments in the Northern Adriatic Sea. Our purpose was to highlight the ecophenotypic variability across tidal levels and to elucidate how tidal currents and waves produced by anthropogenic activities may play a part in modulating shell morphology. Three sampling sites were selected: an open‐sea area 15 km off‐shore and two sites within the lagoon of Venice, the first near one of its three inlets, and the other one in the proximity of Venice city centre. At each sampling site, organisms were seasonally collected at different depths within their vertical zonation, either in the inter‐tidal zone – i.e. at both the highest and lowest tide zonation limits, and subtidally. The mussel shells were analysed by investigation of their morphometric relationships (height/length and width/length ratios) and by elliptic Fourier analysis of the shell contours. Shell thickness and condition index were also evaluated for a better comprehension of energy allocation/partitioning. Estimates based on long‐term measurements, visual observation, wind statistics and wave growth laws allowed an evaluation of the forces acting on shells. At the open‐sea site, the observed phenotypic variability of both shell shape and thickness was clearly related to the tidal vertical zonation. At the two lagoon sites, the currents generated by tidal flow through the inlet and the waves caused by the frequent passage of boats influenced both shell shape and thickness. A trade‐off between protection and growth was apparent along the tide gradient, as emphasized by the differences in the partitioning and allocation of energy between shell and flesh production.  相似文献   

4.
Fulton's K condition factor was applied, for the first time, to inter‐tidal specimens of the shanny (Lipophrys pholis) and long‐spined scorpion fish (Taurulus bubalis) from two English rocky shore and two Welsh rocky shore sites during summer 2010 and winter 2011. As both species contribute to the diet of commercial species such as cod (Gadus morhua) and near‐threatened species such as the European otter (Lutra lutra), their condition may affect that of these predators. Fulton's K found that inter‐tidal Welsh fish maintained a ‘good’ condition between seasons, whereas the inter‐tidal English fish were in a poorer condition during winter. Although condition also changed amongst the sites on each coast, further studies are needed into fish morphologies, environmental parameters, prey availabilities and abundances, and fish specimen sex and maturities.  相似文献   

5.
The inter‐tidal zone around sewage discharges in a Southwest Atlantic shore (Mar del Plata, Argentina) is currently colonized by extensive inter‐tidal reefs of the invasive spionid Boccardia proboscidea. Understanding the links between both human and natural disturbances and the massive development of non‐indigenous species will help prevent marine bioinvasions, which are already favoured by global oceanic trade. We present herein predictive models for variations in the density of B. proboscidea around sewage discharges of Mar del Plata, using environmental (pH, turbidity, temperature, salinity and total organic matter content), weather (wind direction and storm records), spatial (sites) and temporal (season and year) variables. Density variations were modelled by generalized linear models, and model averaging (multimodel inference) was used to obtain predicted values. The highest predicted values of B. proboscidea density occurred at sites to the south of the sewage effluent in spring. These sites are more affected by urban effluent discharges and they showed increased B. proboscidea density when the north wind was predominant. In addition, B. proboscidea density values were higher in sites with 20–22 °C (seawater temperature), high total organic matter content in sediments and low salinity. The averaged model was only a good ‘predictive model’ for sites to the north of the outfall, but was useful as an ‘explanatory model’ in all sites. Such predictions may help to back up conservation and management policies and decisions.  相似文献   

6.
Nearly all of our understanding of rocky inter‐tidal ecology comes from studies conducted at low tide. To study inter‐tidal organisms at high tide, we anchored waterproof digital GoPro® video cameras in wave‐exposed tidepools and recorded the daytime movements of the black turban snail, Tegula funebralis, over the tidal cycle between May and August 2012 near Bodega Bay, California. Overall, snails moved more quickly and presumably foraged more during low tides and on days with warmer air and perhaps water temperatures. This is similar to other ectotherms that exhibit increased metabolic rates, movement and foraging in warmer conditions. Snails also moved less during flood and high tides, may have moved downward in tidepools at flood tides, and showed evidence of reduced activity on days with larger waves. This inactivity and refuge seeking may have been a strategy to avoid dislodgment by waves. Analysis of snail trajectories showed foraging bouts indicated by alternating zig‐zagging and straight movement. There was no effect of temperature, wave height, or tidal phase on distribution of snail turning angles, suggesting that they may have foraged consistently but moved faster during warm conditions and low tides, thereby grazing a larger area. This is one of few direct recordings of inter‐tidal organisms on wave‐exposed rocky shores during high tide. The methods used here are easily transferable to other studies, which are needed to increase our understanding of behaviors that structure rocky shore communities during high tide.  相似文献   

7.
Genetic diversity is the basis for adaptation and therefore of primary scientific interest, especially in species that are threatened by anthropogenic challenges, e.g. climate change and/or pollution. Coral reefs are among the most threatened but also the most diverse ecosystems and have therefore been studied quite extensively. So far, most investigations have focused on scleractinian corals while the equally important reef builders, the hydrozoans, have been less considered. Here we provide the first study of genotypic variability as well as intra‐colonial genetic variability, the co‐occurrence of more than one genotype within a single colony, in Milleporidae based on microsatellites. We analysed two geographically distinct populations from the Millepora dichotoma complex, one from the Red Sea and one from the Great Barrier Reef. Additionally, a population of Millepora platyphylla was analysed from French Polynesia. We compared microsatellite multilocus genotypes and cytochrome c oxidase subunit I haplotypes for each of the three field sites to detect levels of genotypic diversity at the intra‐ and inter‐specific levels. Furthermore, we examined all species for the occurrence of intra‐colonial genetic variability, a recently described mechanism in scleractinian corals that might enhance the adaptive potential of sessile organisms. We found both species and all field sites to be genotypically variable. Twelve mitochondrial haplotypes and 27 multilocus microsatellite genotypes were identified. In addition, intra‐colonial genetic variability was detected in the M. dichotoma complex from the Great Barrier Reef as well as in M. platyphylla from French Polynesia. All of the intra‐colonial genetically variable colonies consisted of one main genotype and a second divergent genotype caused by somatic mutations (mosaicism). Our study proves that Milleporidae are genetically variable and that the phenomenon of intra‐colonial genetic variability also occurs in this important reef‐building family.  相似文献   

8.
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9.
The effects of the 3 main wastewater discharges on the benthic fauna of the Manawatu River were studied between March 1979 and January 1980. At least 4 replicate Surber samples were taken from each of 6 sites, on 5 occasions during this period. Deleatidium sp. (Ephemeroptera), Hydora sp. (Coleoptera), and the Chironomidae were the most useful indicator organisms, according to a ranking system based on the occurrence of significant differences (P<0.05) between populations at different sites. These taxa exhibited significant differences between sites in about 70% of all inter‐site comparisons, using Mann‐Whitney U‐tests. The Coefficient of Similarity was successful at summarising the comparisons between the clean‐water and down‐stream sites, ranging between 95% similarity to the clean‐water site for a recovery site in winter, and less than 10% similarity to the clean water site for the lower reaches in summer. It is suggested that relative indices may be more appropriate than absolute indices for measuring water pollution. Water quality, indicated by species diversity, was generally good (allowing for the effects of agricultural runoff), although midsummer organic loading induced marked changes in benthic species composition, including the disappearance of Deleatidium sp. from several sites.  相似文献   

10.
Research on coralline algal responses to ocean acidification and other environmental stressors has increased in recent years as coralline algae is thought to stand a higher chance of being affected by acidification stress than other macroalgae. To provide context and enhance the existing eco‐physiological framework for climate change studies, it is important to understand the effects of non‐extreme stressors experienced regularly by inter‐tidal coralline algae. In this study, we tested the potentially interacting effects of diurnal and tidal treatments on calcification in the geniculate coralline algae Corallina frondescens and Corallina vancouveriensis using 13C‐labeled bicarbonate. Both species deposited more calcium carbonate during the day than at night, and also when submerged (high tide) compared with when emerged (low tide) in their apical and mature segments (intergenicula). These results indicate that inter‐tidal coralline algae do in fact pay a cost for living inter‐tidally at the edge of an adaptive zone.  相似文献   

11.
The size of bottom‐up subsidies, food and larvae, from the ocean has a profound impact on inter‐tidal communities and populations. Alongshore variations in subsidies are attributed to variation in coastal conditions, but also might be due to variations in surf‐zone hydrodynamics. We tested this hypothesis by comparing surf‐zone phytoplankton concentrations to surf‐zone hydrodynamics as indicated by the width of the surf zones. To minimize the potential effects of alongshore variation in phytoplankton abundance in the coastal ocean, we sampled closely spaced sites (median separation 1 km) over short periods (3 days). Surf‐zone concentrations of coastal phytoplankton taxa (e.g. Chaetoceros spp., Pseudo‐nitzschia spp. and dinoflagellates) varied with surf‐zone width; 65% to 94% of the variability in their concentration is explained by surf‐zone width. Where surf zones were narrow and more reflective, phytoplankton concentrations were one to several orders of magnitude lower than in wider, more dissipative surf zones. The most closely spaced stations were 30 m apart, but represented distinct habitats – a reflective and a more dissipative surf zone. Phytoplankton concentrations in the reflective surf zone were an order of magnitude or more lower than in the adjacent more dissipative surf zone. A reanalysis of a published study on phytoplankton subsidies found similar results. Alongshore variation in surf‐zone hydrodynamics appears to be an important driver of phytoplankton subsidies to the inter‐tidal zone.  相似文献   

12.
Marine plants provide a variety of functions with high economic and ecological values in ecosystems. The above‐ (AG) and below‐ground (BG) systems increase the structural complexity of plants, which also enhance faunal abundance and diversity. The ecological role of the AG compartment in structuring inter‐tidal macrobenthic communities has been widely studied; however, this is not the case for the BG compartment. This study addressed the effects of variation in vegetation complexity (in both AG and BG systems) on associated macrobenthic infauna with respect to abundance, species richness, composition, weight and body type. To achieve this aim, a field experiment using artificial vegetation mimics was carried out using replicated treatments with different AG‐BG complexity ratios. We found a significant increase in the density and the number of taxa of macrobenthic infaunal species in plots with vegetation mimics compared with unvegetated areas, regardless of either AG or BG complexity. This effect was found even when AG parts were not present (i.e. when only BG parts were used). Furthermore, a positive relationship between structural complexity and diversity was recorded. Variation in one or both plant compartments was strongly related to diversity changes in the associated macrobenthic infauna. In conclusion, our experimental set‐up provides the first evidence that the BG compartment is at least as important as the AG compartment in controlling diversity in inter‐tidal vegetated areas because it was able to strongly affect community structure even when the AG system was totally absent.  相似文献   

13.
The population biology of the wedge shell Macomona liliana (Iredale, 1915) was studied at six sites on intertidal sandflats in Manukau Harbour over 2 years. Differences were found in the densities of bivalves between sites, and at each site large seasonal fluctuations in densities were also observed. Within‐site density fluctuations were mainly the result of changes in the numbers of juveniles (< 5 mm long). Length‐frequency distributions were dominated by a single mode associated with new recruits. The only major inter‐site difference was the scarcity of large bivalves at one site. Recruitment to the macrobenthos occurred over an extended period (summer to late winter or spring), but with markedly different levels of recruitment in the two successive years. Length‐frequency plots indicated that growth in the first year was 2–3 mm. The possible involvement of hydrodynamics, inter‐ and intraspecific interactions, and pollution on recruitment, and the importance of mortality and migration to post‐settlement survival are discussed.  相似文献   

14.
On several Auckland shores, a littoral chiton, Sypharochiton pelliserpentis (Quoy and Gaimard, 1835), was widely distributed and common. At Castor Bay it was the commonest chiton, and its density equalled or exceeded that of the commonest limpet (Cellana spp.) over most of the inter‐tidal range. Spot measurements of population density were made at other sites including exposed and sheltered shores. The smallest animals were restricted to the lower shore in pools or on areas of rock which were slow to drain. Exclusive of these small animals, the population structure was similar in pools and water‐filled crevices situated either high or low on the shore. This was also true for populations of animals from drained surfaces, but, at both shore levels, the population structure in the two micro‐habitats (pools and drained surfaces) was distinct.

Single measurements of salinity in the very small volumes of water in which chitons were living gave a range of 13.3–45.8‰. In laboratory experiments at normal temperatures this species could survive these fluctuations for the maximum time possible between tides. Desiccation experiments, in which weight loss was expressed as a percentage of total water content, showed weight loss to depend on size. No significant differences in weight loss were found between populations from the two shore levels and the two micro‐habitats considered, though there were slight survival differences. Desiccation is probably an important factor influencing population structure, but loss of up to 75% of water content could be tolerated before 50% mortality occurred. Osmotic and desiccation stress evoked a characteristic behaviour pattern.  相似文献   

15.
Populations of tropical sea cucumbers, harvested for bêche‐de‐mer, are in a perilous state of conservation, yet there remains a paucity of information on the biology of many harvested species. We examined the population biology of the commercially important curryfish, Stichopus herrmanni, across 2 years on Heron Reef, a protected zone in the Great Barrier Reef (GBR) Marine Park. Stichopus herrmanni, a species recently listed as vulnerable to extinction, is a major target species for the fishery operating in the GBR. The size class distribution and density of S. herrmanni were documented for six sites across Heron Reef. There was distinct spatial variation in the size and density of S. herrmanni across sites, with no significant difference between the 2 years. The smallest individuals found were 10 cm long, some of the only juvenile S. herrmanni documented in nature. Juvenile and sub‐adult populations were found along the leeward reef edge of Heron Reef, a habitat characterized by shallow channels of sand between inter‐tidal coral reef and crustose coralline algae (CCA). Juvenile nurseries of sea cucumbers are rarely observed in nature, making this an important observation for understanding the recruitment and population biology of S. herrmanni. The presence of juveniles in the consolidated CCA habitat each year in autumn following the summer spawning period, and the absence of small individuals several months later in spring, suggests an ontogenetic migration or displacement of these individuals to adult habitat. The distribution of larger S. herrmanni suggests intra‐reef connectivity and migration into deeper lagoon areas. This study contributes to understanding the population dynamics of this vulnerable species, a consideration for fisheries management in light of increasing global harvest.  相似文献   

16.
Rock pools can be found in inter‐tidal marine environments worldwide; however, there have been few studies exploring what drives their, fish species composition, especially in Australia. The rock‐pool environment is highly dynamic and offers a unique natural laboratory to study the habitat choices, physiological limitations and adaptations of inter‐tidal fish species. In this study rock pools of the Sydney region were sampled to determine how the physical (volume, depth, rock cover and vertical position) and biological (algal cover and predator presence) parameters of pools influence fish distribution and abundance. A total of 27 fish species representing 14 families was observed in tide pools at the four study locations. The five most abundant species were Bathygobius cocosensis, Centropogon australis, Enneapterygius atrogulare, Lepidoblennius haplodactylus and Microcanthus strigatus, which together represented 71% of the total number of fish recorded. Larger rock pools containing more algal and rock ledge cover hosted a larger and more diverse population of fish. Furthermore, certain species were only found in pools with specific characteristics, such as the presence of loose shells, a variety algae or rock cover, suggesting a high degree of habitat specificity. By contrast, some species were ubiquitous and thus can likely tolerate a wide variety of physical conditions.  相似文献   

17.
This study examined the phylogeography of the barnacle Fistulobalanus albicostatus, which inhabits mangroves and estuarine shores in the West Pacific. Differentiation in the mitochondrial cytochrome c oxidase subunit I (COI) and 12S ribosomal RNA (12S) genes of 401 specimens of F. albicostatus was examined in samples from 16 locations in the West Pacific, ranging from Honshu to Southern China. Our results revealed that F. albicostatus comprises two major clades exhibiting a COI divergence ranging from 1.25% to 2.8%. Clade A demonstrated the widest distribution, ranging from Japan to China, and was divided into three subclades occurring in the South China Sea (A1), Okinawa (A2), and Honshu, Korea and Qingdao (A3). Clade B was determined to be endemic to Okinawa; i.e. two endemic lineages occur in this island. Thus, F. albicostatus resembles several inter‐tidal species in having clades that are endemic to Okinawan waters. Nevertheless, in contrast to the rocky inter‐tidal barnacles Tetraclita spp. and Chthamalus malayensis, F. albicostatus was not found to be separated into continental and oceanic populations, but instead is divided into northern and southern clades, probably because of the Yangtze River discharge, which limits gene flow between the northern and southern populations.  相似文献   

18.
胶州湾辛岛潮间带大型底栖动物生态学调查   总被引：3，自引：1，他引：3       下载免费PDF全文
利用2003年8月至2004年5月(夏、秋、冬、春季)4个季度月在胶州湾辛岛潮间带的3个不同潮区的调查资料进行分析。结果共获得大型底栖动物43种,其中低潮区出现27种,中潮区和高潮区20种和19种,有6种属于3个潮区共有种。大型底栖动物总平均栖息密度为102.5个/m2,5月最高,为144.67个/m2,2月最低,为52.66个/m2;总平均生物量为60.01g/m2,11月最高,为102.99g/m2,2月最低,仅为11.87g/m2。本区大型底栖动物的栖息密度和生物量有明显的季节变化。  相似文献   

19.
The epibiotic communities (diatoms and metazoans) on the outer surfaces of the shell of the barnacle Balanus amphitrite (BSh) and its opercular valves (the scutum and tergum; BST) were investigated on a monthly basis for 1 year in a tropical monsoon‐influenced estuary and compared with that of the surrounding rock biofilm. BSh and BST were rich in the diatoms Achnanthes longipes and Melosira nummuloides and amongst the invertebrates, nematodes and tardigrades were abundant. To the best of our knowledge, this is the first report of epibiosis on the acorn barnacle. Diatom abundance was at its maximum during the monsoon season on all the inter‐tidal substrata i.e. BSh, BST and rock. A significant correlation was found between the density of diatoms and invertebrates associated with the BSh and BST, possibly because of the trophic relationship between them or the suitability of the physical environment. The possible role of these epibionts on the settlement of this barnacle species is currently unknown and needs further investigation.  相似文献   

20.
Spatial and temporal variation in tropical inter‐tidal communities is poorly known, making predictions about the effects of climate change and other anthropogenic disturbances difficult. Along Southwest O‘ahu, Hawai'i, local residents are concerned about the environmental effects of coastal development and the perceived loss of targeted algal species, which are collected for human consumption. To describe the coastal benthic community and better understand the processes that form and maintain it, the abundance and composition of macroalgae were sampled in the region's inter‐tidal zone from 2006 to 2015. Sixty‐six macroalgal species and two broad algal assemblages were identified that corresponded to substrate topography and sand influence at a similar tidal elevation. Along flat carbonate benches with a sand beach, Phaeophyceae and Rhodophytes occurred in almost equal proportions, while shores with slightly more topographic relief and angular substrate were dominated by Rhodophytes. Foliose or turf algal forms were most common. Surveys captured the local invasion of an alga, Avrainvillea sp. and significant declines in abundant macroalgae in 2015 after a period of unseasonably warm, calm water. Temporal changes in algal assemblages were related to maximum water temperature and wave height but not precipitation. Thus, algal assemblages appear to be structured by local beach morphology as they interact with sand and wave activity and episodically by unusual weather events. However, manipulation and continuous monitoring of the algal assemblages coupled to sensing of the localized environment is necessary to confirm factors related to assembly maintenance and recent species shifts.  相似文献   

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