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1.
《Harmful algae》2017
Concern regarding Benthic Harmful Algal Blooms (BHABs) is increasing since some harmful benthic species have been identified in new areas. In the Mediterranean basin, the most common harmful benthic microalgae are Ostreopsis cf. ovata and Prorocentrum lima, which produce palytoxin-like compounds and okadaic acid respectively, and the need to implement monitoring activities has increased. However, a general agreement on appropriate strategies (e.g. sampling season, definition of alarm thresholds, etc.) is still lagging behind, especially for P. lima, whose proliferation dynamics are still poorly known. 相似文献
2.
Catches of ants in the two most commonly-used forms of pitfall trap (‘test-tube’ traps, ca 18 mm diameter; ‘coffee cup’ traps, ca. 70 mm diameter) are compared from samples in open grassy woodland in southern Victoria, Australia. The 25 morphospecies found in the narrower traps were all represented among the 31 morphospecies collected in the larger traps. Either pattern is adequate to collect samples for broad inter-treatment comparisons and documentation of the more typical and representative fauna, but larger traps may have some advantage if more complete inventory is sought. 相似文献
3.
《Harmful algae》2017
Despite the potential negative human health, ecological and economic impact, the ecology of harmful benthic dinoflagellate blooms remains largely unknown. This is probably due to the complex interactions among biotic and abiotic drivers that influence blooms, but also to the difficulty in quantifying cell abundance in a comparable way over large spatial and temporal scales. One of the recognized priorities for bHABs (benthic Harmful Algal Blooms) assessment is developing and standardizing methods that can provide comparable data. In this context, the Benthic Dinoflagellates Integrator (BEDI), a new non-destructive quantification method for benthic dinoflagellate abundances, has been developed and tested within the present study. The rationale behind the BEDI standard assessment method is that mechanical resuspension of cells enables the quantification of abundances as cells per unit of seabed surface area (i.e. cells mm−2) or as Potentially Resuspended cells per unit of volume (PRcells ml−1), by integrating both cells in the biofilm and those in the surrounding water. Estimations of Ostreopsis performed with BEDI method are independent of the substratum (i.e. macroalgal species) or the dominant ecosystem (i.e. algal forests or turfs, seagrass beds, coral reefs) and potentially allow the comparison of benthic dinoflagellate blooms over broad temporal and spatial scales. The first application of the BEDI method, presented in this study, gave encouraging results: the characterization of blooms of Ostreopsis cf. ovata at three sites in the NW Mediterranean Sea is consistent with results derived from the other commonly applied methods. Quantification of the ratio between abundances of cells in the biofilm and in the surrounding water was calculated for the first time per unit of seabed surface area, demonstrating that the highest abundances of cells (the stock), and therefore the associated risk for human health, are in the biofilm. For risk assessment purposes, conversion values for commonly used monitoring alert thresholds of Mediterranean Ostreopsis blooms are provided. 相似文献
4.
Until the E.U. Water Framework Directive listed benthic invertebrates as a biotic element to be used for ecological classification of lakes, techniques for the assessment of the response of littoral invertebrates to anthropogenic pressures were extremely limited compared with those of rivers and lake profundal zones. We describe here the development of an ecological classification model based on changes of littoral invertebrate assemblages across a gradient of eutrophication, which is the most widespread anthropogenic pressure on lakes across Europe. The model comprises three derived parameters, two of which were developed from taxon-specific optima along a total phosphorus gradient calculated using canonical correspondence analysis, and the third based on invertebrate abundance. Combining the parameter metrics, we can estimate the ecological quality ratio (EQR), relative to those from paleolimnologically-confirmed reference lakes. The model was tested using independent samples collected from both hard and soft substrata and across two seasons from 45 lakes, comprising three alkalinity groups (n = 15 in each), and across gradients in water column total phosphorus concentrations. For hard substrata, EQRs were related consistently and highly significantly to water column concentrations of total phosphorus, accounting for the majority of the variance in every alkalinity group. For samples taken from soft substrata, a significant relationship was found only for high alkalinity lakes, accounting for a moderate proportion of the variability in water column total phosphorus concentrations. Our results compare highly favourably with those from other aquatic ecological assessment methods, irrespective of the faunal or floral group upon which they are based, demonstrating that littoral invertebrate assemblages can provide a statistically robust prediction of nutrient status when samples are collected from hard substrata. While the method was developed specifically to assess nutrient pressures on littoral invertebrates, many lakes are subject to multiple pressures. The development of classification models that incorporate multiple pressures presents a particularly significant challenge for the implementation of the Water Framework Directive, requiring both reliable identification of minimally-impacted reference states and incorporation of pressures that are unlikely to interact in predictable ways. 相似文献
5.
For several animal taxa, non-lethal techniques that do not rely on collecting individuals are routinely used to assess biodiversity (e.g. point counts in birds). Identification often relies on the ability of the observer, are subjected to errors, but populations are not impacted. Thus, multiple counting sessions (MCS) that allow using robust analyses (e.g. unbiased Chao richness estimate) are available. However, for most species (e.g. arthropods), trap systems must be set up. Killed individuals are collected and later accurately identified in the laboratory, but unbiased MCS become unavailable. Environmental DNA bar-coding provides an alternative, yet it requires important technical support and is not designed for MCS. Lethal rapid biodiversity assessments (RBA), derived from classical trap surveys and based on less accurate identifications (morphospecies are used), have been successfully developed to relax technical constraints. In this study, we combined non-lethal and RBA approaches to address logistical, analytical and ethical issues. We tested five versions of a protocol to visually survey the macro-fauna of hedgerows. A large number of individuals were directly identified in the field, mostly arthropods but also vertebrates. Identification error varied with taxonomic level and lineage, but remained low at the morphospecies level. Importantly, estimates tended to reach asymptotes, suggesting that local richness was appropriately appraised. Like any technique, non-lethal RBA (NL-RBA) present both advantages and weaknesses, and may improve the toolbox to survey biodiversity. 相似文献
6.
Given that diatom assemblages are a well-recognised method of characterising the water quality in freshwater streams, it seems reasonable to investigate its applicability to solar saltfields. A summer collection of benthic diatoms was undertaken in the salinas of the Dry Creek solar saltfields in South Australia for this purpose. The facility inputs seawater both from a low nutrient samphire creek and poorer quality, high nutrient samphire creek. Salinity and nutrient status of the pools and concentrating salinas have been thoroughly characterized over many years. The addition of JJ periphytometers to the sampling regime in the summer of 2001–2002 allowed the collection of benthic diatoms from these sites. Of the 69 species collected during the study, 16 species occurred only in oligotrophic waters with salinities less than 70 g/l TDS (total dissolved solids). Twenty species of diatoms occurred only in the eutrophic waters with salinities less than 70 g/l TDS, eight species were restricted to the hypersaline ponds and the remainder were undiscriminating in their ecological preferences. Guest Editor: John M. Melack Saline Water and their Biota 相似文献
7.
Quantitative macroscopic's indexes have been used to compare three trophic models of the exploited benthic ecosystem of Tongoy Bay. In this system the primary productivity and benthic invertebrates are more important in the cycling of biomass. The models were built with a similar number of compartments for the years 1992, 2002 and 2012, using Ecopath with Ecosim (EwE). Odum and Ulanowicz's frameworks and ecological network analysis were then used to estimate the levels of maturity, growth and development of the system. Likewise, “keystoneness” indexes – at each time – were also estimated for the models. Our results show that Tongoy Bay exhibited an increase in maturity and development (“health”) in 2012 compared to past conditions, which was reflected by (1) an increase in the total system biomass, total system throughput, AMI, and absolute Ascendency, (2) higher flow and increased efficiency of transferred energy and its proportion at higher trophic levels, (3) an increase of recycling (FCI), (4) a reduction of NPP/R and NPP/B ratios of the system, and (5) an increase in the number of compartments trophically linked that comprise the keystone species complex. We argue that these results are a consequence of reduced fishing pressure on this benthic system in recent years. This study shows that the fishing would not only have a direct impact on exploited species, but would also affect the structure and functioning of the ecosystem. The information obtained could help to improve the management of fisheries resources, evaluating surveillance indicators that can show the putative changes of intervened ecosystems. 相似文献
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9.
For an ecological monitoring program to be successful over the long-term, the perceived benefits of the information must justify the cost. Financial limitations will always restrict the scope of a monitoring program, hence the program’s focus must be carefully prioritized. Clearly identifying the costs and benefits of a program will assist in this prioritization process, but this is easier said than done. Frequently, the true costs of monitoring are not recognized and are, therefore, underestimated. Benefits are rarely evaluated, because they are difficult to quantify. The intent of this review is to assist the designers and managers of long-term ecological monitoring programs by providing a general framework for building and operating a cost-effective program. Previous considerations of monitoring costs have focused on sampling design optimization. We present cost considerations of monitoring in a broader context. We explore monitoring costs, including both budgetary costs, what dollars are spent on, and economic costs, which include opportunity costs. Often, the largest portion of a monitoring program budget is spent on data collection, and other, critical aspects of the program, such as scientific oversight, training, data management, quality assurance, and reporting, are neglected. Recognizing and budgeting for all program costs is therefore a key factor in a program’s longevity. The close relationship between statistical issues and cost is discussed, highlighting the importance of sampling design, replication and power, and comparing the costs of alternative designs through pilot studies and simulation modeling. A monitoring program development process that includes explicit checkpoints for considering costs is presented. The first checkpoint occurs during the setting of objectives and during sampling design optimization. The last checkpoint occurs once the basic shape of the program is known, and the costs and benefits, or alternatively the cost-effectiveness, of each program element can be evaluated. Moving into the implementation phase without careful evaluation of costs and benefits is risky because if costs are later found to exceed benefits, the program will fail. The costs of development, which can be quite high, will have been largely wasted. Realistic expectations of costs and benefits will help ensure that monitoring programs survive the early, turbulent stages of development and the challenges posed by fluctuating budgets during implementation. 相似文献
10.
The development of biological indicators for assessing ecological conditions in streams and rivers is urgently needed in China, particularly in heavily impacted regions. The aim of this study was to develop and apply benthic macroinvertebrate-based multimetric indices (MMIs) for the assessment of streams and rivers in the western hill and eastern plain aquatic ecoregions of the Taihu Basin. MMIs were based on samples collected from October 16 to November 8 2012 at 120 sites in streams and rivers. Least disturbed sites defined the reference conditions. Chemical water quality, physical habitat, and land use were used as criteria to identify reference sites in the basin. Metrics related to benthic macroinvertebrate richness, composition, diversity and evenness, pollution tolerance, and functional feeding groups were screened by range, sensitivity, responsiveness, and redundancy tests. Total number of taxa; percentage of Ephemeroptera, Trichoptera and Odonata (% ETO); Berger–Parker’s index (BP); Biotic index (BI); and percentage of filterers–collectors (% FC) were used to construct the MMI for the western hill aquatic ecoregion (MMIW). Total number of taxa, percentage of Crustacea and Odonata (% CO), BP, BI, and % FC were used to construct the MMI for the eastern plain aquatic ecoregion (MMIE). The MMI scores were obtained by combining the rating categories (excellent, good, fair, poor, and very poor). The MMIs were tested using a separate subset of the data, and the results indicated that the newly developed MMIs were robust in terms of percentage of sites correctly classified, coefficient of variation, box-separation ratios, and separation powers. The ecological status was then evaluated based on the MMI scores. The results indicated that the general ecological status of streams and rivers in the Taihu Basin was rated lower than “good”, the western hill aquatic ecoregion was rated “fair” and the eastern plain aquatic ecoregion was rated “poor”. Moreover, the MMIs showed a significant negative response to an increasing gradient of disturbance. Therefore, these preliminary MMIs can be used as assessment tools in ecological biomonitoring and management of the Taihu Basin. 相似文献
11.
Wim Gabriels Peter L. M. Goethals Andy P. Dedecker Sovan Lek Niels De Pauw 《Aquatic Ecology》2007,41(3):427-441
The effect of environmental conditions on river macrobenthic communities was studied using a dataset consisting of 343 sediment
samples from unnavigable watercourses in Flanders, Belgium. Artificial neural network models were used to analyse the relation
among river characteristics and macrobenthic communities. The dataset included presence or absence of macroinvertebrate taxa
and 12 physicochemical and hydromorphological variables for each sampling site. The abiotic variables served as input for
the artificial neural networks to predict the macrobenthic community. The effects of the input variables on model performance
were assessed in order to identify the most diagnostic river characteristics for macrobenthic community composition. This
was done by consecutively eliminating the least important variables and, when beneficial for model performance, adding previously
removed ones again. This stepwise input variable selection procedure was tested not only on a model predicting the entire
macrobenthic community, but also on three models, each predicting an individual taxon. Additionally, during each step of the
stepwise leave-one-out procedure, a sensitivity analysis was performed to determine the response of the predicted macroinvertebrate
taxa to the input variables applied. This research illustrated that a combination of input variable selection with sensitivity
analyses can contribute to the development of reliable and ecologically relevant ANN models. The river characteristics predicting
presence or absence of the benthic macroinvertebrates best were the Julian day, conductivity, and dissolved oxygen content.
These conditions reflect the importance of discharges of untreated wastewater that occurred during the period of investigation
in nearly all Flemish rivers. 相似文献
12.
The European Union Habitats Directive (HD) obliges member states to assess the conservation status of marine habitat types but no explicit methodologies for assessing the quality of habitats have been stated in the directive or accompanying documents. In this study, a system was developed to assess the structure and functioning of three important marine habitat types in the Estonian sea area: sandbanks (HD code 1110), mudflats (1140), and reefs (1170). The assessment system includes a list of ecological criteria and favourable reference values together with procedural rules and field sampling locations. The habitat types listed in the HD are broadly defined and may encompass different communities depending upon distinct environmental gradients. By considering these environmental gradients the habitat types reefs and sandbanks were zoned and the assessment criteria and corresponding favourable reference values were defined separately for each zone. A set of several metrics like benthos indices, community variables, presence of sensitive or typical species, proportions of functional or taxonomic groups were tested as potential criteria for determining habitat quality. The most appropriate criteria were selected for incorporation into the assessment system based on ecological eligibility, suitability to local conditions, occurrence rates of benthic species, responses to disturbances, statistical properties of distribution of measured values, and practical considerations. Extensive benthos database (records from the whole Estonian sea area, 1995–2014) was used to calculate values of criteria to support the selection of criteria and to derive reference values. In order to fully take into account their crucial role in maintaining the structure and functioning of habitats, the criteria on habitat-forming species were assigned higher hierarchical order in the assessment scheme compared to other criteria. Special field works were carried out to assess the status of the three habitat types in 2015. The quality of all three monitored habitats was assessed to be in a favourable status. Additionally, the distributions of the three habitat types were mapped. To date, this is the first study in the Baltic Sea region that formulates HD compliant explicit criteria, reference values, and assessment procedures for several marine habitat types. The main challenges of the study were to derive assessment criteria and favourable reference values that are ecologically relevant and practically feasible. 相似文献
13.
14.
Under the Water Framework Directive (WFD) benthic Ecological Quality Ratios (EQRs) are important tools for assessing Ecological Status (ES) of coastal and transitional waters. Calculation of the Multivariate-AZTI Marine Biotic Index (M-AMBI) EQR is based on the proportions of sensitive and stress tolerant benthic invertebrate species, number of species and Shannon–Wiener diversity. The sensitivity of many tropical/sub-tropical taxa has not yet been determined, presenting a barrier to the direct transfer of WFD EQRs, and the ideas underpinning them, to the management of coastal waters beyond Europe. To overcome this we examine using higher taxonomic level data with M-AMBI.Before applying such approaches to assessing ES in new geographical regions it is essential to determine the effects of using higher taxonomic level data on M-AMBI in areas where the tool was developed. To this end, we use macrofaunal data from three well studied sites in north-western Europe to examine the effects of using taxonomic level data higher than species on M-AMBI. Using the European datasets M-AMBI ES classification was shown to be robust to changes in taxonomic level data. We test the suitability of family-level M-AMBI for assessing ES in subtropical Hong Kong waters. Family level M-AMBI was useful in detecting stress in Hong Kong, where it successfully detected temporal and spatial shifts in ES in response to seasonal hypoxia and salinity variability, and anthropogenic organic enrichment. 相似文献
15.
Although shoot patchiness has long been studied in Posidonia oceanica meadows, small scale spatial structure of P. oceanica meadows is poorly known, as very few studies focused on this feature. In order to analyze spatial patterns within P. oceanica meadows that appear uniformly dense and undisturbed, we collected shoot density data at the Capo Rizzuto Marine Protected Area (NE Mediterranean, Italy). Intensive sampling was carried out within a square lattice at small spatial scale (i.e. in the 10−1–102 m2 range) and shoot counts were obtained from sample quadrats of different size (60, 40, 20 cm). Spatial data analysis highlighted high irregularity in shoot density from centimetric to larger spatial scales. Therefore the deviation between shoot density estimates obtained using conventional methods and the overall average of quadrat counts (assumed as the best estimate for true density) was never negligible even when larger counting quadrats or higher numbers of replicates were adopted. While shoot density is regarded as the most important property of a P. oceanica meadow and as an indicator of ecosystem health, uncertainty in density estimates and unknown expected errors impair the effectivity of this approach. However, we showed that error could be predicted based on sampling intensity and design in an apparently uniform meadow. Although results from a single case study cannot be generalized, our work is the first attempt at analyzing the problems related to density estimates obtained from shoot counts and it shows how sampling can be optimized to achieve any desired level of accuracy. 相似文献
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17.
Jonne Kotta Ilmar Kotta Mart Simm Ain Lankov Velda Lauringson Arno Põllumäe Henn Ojaveer 《Helgoland Marine Research》2006,60(2):106-112
Population dynamics and ecological impacts of the cirriped Balanus improvisus, the polychaete Marenzelleria neglecta and the cladoceran Cercopagis pengoi were investigated in the north-eastern Baltic Sea. After an increase during the first decade of invasion, the density of M. neglecta and C. pengoi declined afterwards. The studied abiotic environmental variables did not explain the interannual variability in the seasonal cycles of M. neglecta and C. pengoi indicating that the species are at their initial phase of invasion. The population dynamics of B. improvisus was best described by water temperature. B. improvisus promoted the growth of the green alga Enteromorpha intestinalis. M. neglecta enhanced the content of sediment chlorophyll a and reduced growth and survival of the polychaete Hediste diversicolor and growth of the amphipod Monoporeia affinis. Concurrent with the invasion of C. pengoi the abundance of small-sized cladocerans declined, especially above the thermocline. C. pengoi had become an important food for nine-spined stickleback, bleak, herring and smelt. 相似文献
18.
A gap in the European Water Framework Directive (WFD) is addressed, aiming for the development of an ecological quality status assessment tool based solely on the Biological Quality Element benthic macroinvertebrates from intertidal rocky shores. The proposed Rocky shore Macroinvertebrates Assessment Tool (RMAT) was tested and validated along disturbance gradients (organic enrichment). During the whole process, the response of widely used metrics (e.g. Hurlbert index, Shannon-Wiener index, AZTI’s Marine Biotic Index; Bentix biotic index) and models (i.e., metrics combined) was compared to results provided by the Marine Macroalgae Assessment Tool to the same sampling sites.The RMAT is a multimetric index compliant with the WFD based on the benthic macroinvertebrates community, combining ‘abundance’ (Hurlbert index) and ‘taxonomic composition’ (Bentix index using density and biomass data) metrics. It performed well along anthropogenic disturbance gradients, showing ecological quality increasing from close to far away from the disturbance.The RMAT is a promising tool for rocky shore ecological assessment in the scope of the WFD or other monitoring activities worldwide. 相似文献
19.
Variability in the ecological quality assessment of reference sites was tested on small headwater streams in Ireland. Although
headwater streams constitute a large portion of the river channel network, they are not routinely monitored for water quality.
Various metrics were used including the Irish Q-value and the newly developed Small Streams Risk Score (SSRS), and metrics
applied elsewhere in the Atlantic biogeographic region in Europe, including the Biological Monitoring Working Party score
(BMWP), the Average Score per Taxon (ASPT), the Ephemeroptera, Plecoptera and Trichoptera taxa (EPT), the Belgium Biotic Index
(BBI) and the Danish Stream Fauna Index (DSFI). The AQEM (version 2.5a) assessment software was used to apply some of these
metrics. The spring and summer datasets are used to test the performance of biotic metrics with respect to season, and the
applicability of their use to assess the ecological quality of wadeable streams. The quality status of most sites assigned
by the various metrics was high using the spring invertebrate data, and an apparent considerable deviation in quality status
occurred when the summer data was applied. Seasonal differences were noted using all the biotic indices and are attributed
to the absence of pollution-sensitive groups in summer. Seasonal variability in the water quality status was particularly
evident in acidic streams draining non-calcareous geologies with peaty soils that had relatively lower numbers of taxa. Some
indices applied reflect a greater seasonal difference in the quality category assigned. The least amount of variability between
seasons was obtained using the ASPT and the SSRS risk assessment system. Results suggest that reference status is reliably
reflected in spring when more pollution-sensitive taxa were present, and that a new ecological quality assessment tool is
required for application in summer when impacts may be most severe. This highly heterogeneous freshwater habitat seems to
have too few taxa present in the summer to reliably determine the ecological quality of the stream using the available indices.
Handling editor: R. Bailey 相似文献
20.
Jorge M. Lobo 《Biodiversity and Conservation》2008,17(4):873-881
The compilation of all the available taxonomic and distributional information on the species present in a territory frequently generates a biased picture of the distribution of biodiversity due to the uneven distribution of the sampling effort performed. Thus, quality protocol assessments such as those proposed by Hortal et al. (Conservation Biology 21:853–863, 2007) must be done before using this kind of information for basic and applied purposes. The discrimination of localities that can be considered relatively well-surveyed from those not surveyed enough is a key first step in this protocol and can be attained by the previous definition of a sampling effort surrogate and the calculation of survey completeness using different estimators. Recently it has been suggested that records from exhaustive databases can be used as a sampling-effort surrogate to recognize probable well-surveyed localities. In this paper, we use an Iberian dung beetle database to identify the 50 × 50 km UTM cells that appear to be reliably inventoried, using both data derived from standardized sampling protocols and database records as a surrogate for sampling effort. Observed and predicted species richness values in the shared cells defined as well-surveyed by both methods suggest that the use of database records provides higher species richness values, which are proportionally greater in the richest localities by the inclusion of rare species. 相似文献