Deliverable D 3 . 2-2 : Report on uncertainty in macrophyte metrics (original) (raw)
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Hydrobiologia, 2006
The application of macrophytes in freshwater monitoring is still relatively limited and studies on their intercalibration and sources of variation are required. Therefore, the aim of the study was to compare selected indices and metrics based on macrophytes and to quantify their variability. During the STAR project, several aspects influencing uncertainty in estimation of the ecological quality of river were assessed. Results showed that several metrics based on the indicative value of plant species can be used in evaluation of the ecological status of rivers. Among estimated sources of variance in metric values the inter-surveyor differences had the lowest effect and slightly stronger were the influences of temporal variation (years and seasons) and shading. The impact of habitat modification was the most important factor. Analysis showed that some of macrophyte-based metrics (notably MTR and IBMR) are of sufficient precision in terms of sampling uncertainty, that they could be useful for estimating the ecological status of rivers in accordance with the aims of the Water Framework Directive.
Applied Vegetation Science, 2018
Do natural and anthropogenic physical disturbances equally affect the distribution of aquatic plants communities? Can hydrodynamic and geomorphological features be used to predict the establishment of macrophyte communities at the shoreline scale? Locations: The study was carried-out in two large, shallow lakes in southwestern France, the southern hotspots of isoetid distribution in Europe. Methods: Based on field observations (vegetation occurrence and anthropogenic modifications of the shore) and data generated by a geographical information system (wave exposure, wave-induced sediment resuspension, slope and land cover), we defined sites and community groups using cluster and indicator species analyses. The groups were then analyzed by means of a statistical classifier (Random Forest). These different steps in data treatment enabled us to characterize the importance of each physical factor in determining macrophytes occurrence and distribution. As a result, a predictive map to forecast aquatic plant distribution at the shoreline scale was obtained. Results: Anthropogenic disturbances were less important parameters than natural physical variables in structuring the distribution of lakeshore macrophytes. Within natural factors, wave-induced sediment resuspension and slope had the most impact; nevertheless, the presence of swimming areas seemed to have a strong impact on aquatic habitats, being correlated with the total absence of aquatic vegetation. The predictive map obtained through the model spatially defined the position and occurrence of suitable sites for the settlement of both invasive, and rare and endangered species. Conclusions: In this study, natural disturbances play a major role in structuring aquatic plant distribution over physical anthropogenic ones. The model contributes to improving knowledge on plant communities with respect to local hydrodynamic and morphological features of lakeshores. Furthermore, the model provides the production of a predictive map as a useful tool for the management of aquatic vegetation in temperate shallow lakes.
Journal of Limnology, 2001
In the aquatic environment biology and hydrology should assist each other in explaining the establishment, fluctuation, and limitation of the aquatic vegetation. However, the description of running and still waters by hydrology and habitat hydraulics, and the description of the aquatic vegetation, and its dynamics, rarely lead to results on a comparable scale. This is due to some intrinsic methodological features of both sciences, but also due to the fact that there is not much effort to find a common basis of scale. This is to no surprise because most of the time a hydrologist, and vice versa a biologist, tries to solve problems on his own, rarely calling for a partner from the other field. In the personal view of a biologist aspects are pointed out which may lead to a better interpretation of biological processes through habitat-related hydrological and/or hydraulic assessments. The terms macrophytes, environment and success are defined first. The function of macrophytes as a part of the aquatic ecosystem is explained, and related to important environmental factors. Examples are given for water flow as the most prominent abiotic factor. With respect to water flow and light the assessment of these parameters should be more detailed regarding space and time to be relevant to the scales in which aquatic plant life takes place. With regard to nutrient assessment spatial resolution is not as sensitive an issue as long as the water body, and not the interstitial, is concerned. However, any increase in detail will considerably raise the effort, and the cost, of data acquisition. Measuring plant "success" with physiological methods and biometrics can be too complicated for in situ work. Methods fitted to single species spatial development may cope with such problems and GIS is the tool to choose in such cases. Finally the urgent need to find common scales among hydrologists and biologists is addressed.
Knowledge and Management of Aquatic Ecosystems, 2014
macrophytes, lakes, rivers, plant ecology, ecological assessment Nous avons analysé la composition spécifique et l'abondance de macrophytes, la chimie de l'eau et les paramètres hydromorphologiques de tous les principaux tronçons des rivières et les lacs du bassin versant de la rivière de plaine Wel, en Pologne. Nous avons étudié, (i) les facteurs hydromorphologiques et physicochimiques qui expliquent le mieux la composition des espèces de macrophytes, Article published by EDP Sciences K. Szoszkiewicz et al.: Knowl. Managt. Aquatic Ecosyst. (2014) 415, 08 écologie végétale, évaluation écologique
Knowledge and Management of Aquatic Ecosystems, 2013
The relationship between macrophytes and environmental conditions of lotic and lentic habitats was studied within two distinct biogeographical regions (Pannonian and Carpathian) represented by two model areas (Borská nížina lowland and Turčianska kotlina basin) in 2011. Altogether, 72 taxa of macrophytes were found within both studied biogeographical regions, while almost a third of them grew only in one from the regions. Species-environmental variables relationship was studied by Canonical Correspondence Analysis (forward selection), which revealed that three and seven environmental variables explaining 10.35% and 24.45% of variance of species data had significant effect on species composition of macrophytes in the Pannonian and Carpathian region, respectively. Flow regime and the portion of fine substrate on the bottom are the main drivers of species composition-environmental condition relationships and explained 3.57% and 6.21% of variance in the Pannonian and Carpathian region, respectively. However, the highest values of pure effect on species composition was detected in case of Altitude (Pannonian region; 3.81%) and Connectivity (Carpathian region; 3.19). Based on the variation partitioning, landscape variables (including geographical variables; Pannonian region; 6.8%) and hydrological variables (including morphological variables of the bottom; Carpathian region; 11.3%) explained a bigger portion of the variability of macrophytes in regions than the other groups of environmental variables.
First steps in the Central-Baltic intercalibration exercise on lake macrophytes: where do we start
Aquatic Ecology, 2008
The Water Framework Directive (WFD 2000) defines macrophytes as one of the biological groups required for the ecological assessment of European surface waters. Several indices for macrophyte assessment have been proposed or are currently in use by different European states. As a first step towards performing an intercalibration of these indices a common dataset was developed. This dataset contains abundance data on 789 macrophyte species from 316 different lake sites in ten European countries. Various common species and genera were identified as indicators of reference and impacted conditions within the dataset. Cluster analysis of macrophyte data, supported by non-metric multidimensional scaling, indicated that clusters formed were more reflective of their source country rather than lake type. This might be caused by differences in regional climate, biogeography, monitoring techniques, or a combination of these factors. A total of six national indices were applied to assign quality classes to the lakes. However, this produced results that often differed by one or two quality classes for the same site. We foresee that a more precise intercalibration exercise is necessary, and it should be based on more detailed data considering both seasonality and the latitudinal differences within the area covered.