Large rivers are amongst the most degraded ecosystems. We studied a relationship between hydromorphological degradation and benthic invertebrates in large rivers in Slovenia. Five indices of the Slovenian hydromorphological assessment methodology were used to develop a HM stressor gradient. Natural type-specific habitat diversity was considered in the hydromorphological stressor gradient building and thus two hydromorphological types of large rivers were defined. CCA ordination with five HMindices and 315 benthic invertebrate taxa revealed variations in taxa response along the HM stressor gradient. First CCA axis species values were used to develop a taxon-specific river fauna value (Rfi), whereas tolerance values (biplot scaling) were used to determine a hydromorphological indicative weight (HWi). Rfi, HWi, and log5 abundance classes were combined using weighted average approach to construct aRiver fauna index for large rivers (RFIVR). Several additional benthic invertebrate-based metrics were also tested against the HQM. A Slovenian multimetric index for assessing the hydromorphological impact on benthic invertebrates in large rivers (SMEIHVR) was constructed from the RFIVR and a functional metric %akal + lithal + psammal taxa (scored taxa = 100%). The strong relationship between hydromorphological stressor gradient and SMEIHVR index provides us with an effective assessment system and river management tool.
COBISS.SI-ID: 2706511
In this study, we review and intercalibrate 13 benthic invertebratebased tools across Europe. These assessment tools address different human impacts: acidification (3 methods), eutrophication (3 methods), morphological alterations (2 methods), and a combination of the last two (5 methods). For intercalibration, the methods were grouped into four intercalibration groups, according to the habitat sampled and putative pressure. Boundaries of the ‘good ecological status’ were compared and harmonized using direct or indirect comparison approaches. To enable indirect comparison of the methods, three common pressure indices and two common biological multimetric indices were developed for larger geographical areas. Additionally, we identified the best-performing methods based on their responsiveness to different human impacts. Based on these experiences, we provide practical recommendations for the development and harmonization of benthic invertebrate assessment methods in lakes and similar habitats.
COBISS.SI-ID: 7326049
In the last decades, hydromorphological degradation of rivers has gained more attention in river management, stressing the importance of understanding the links between hydromorphology and aquatic assemblages. The present study investigated general patterns in the response of benthic invertebrate assemblages to single morphological features along naturally diversified Slovenian rivers. The whole gradient of local habitat quality (river habitat quality, RHQ) and habitat modification (river habitat modification, RHM) features, according to the Slovenian hydromorphological assessment method, was covered. Regional natural characteristics explained the low share of RHQ and RHM variability, indicating nonregional presence of morphological features. The analysis identified predominant flow and predominant channel substrate as the most important RHQ features. We found that in contrast to RHQ features, RHM features had low explanatory power. These results suggest a weaker response of benthic invertebrate assemblages to the physical alteration itself than to the effect that the alteration exerts on habitat quality features. Variance partitioning among three environmental variable groups revealed predominantly independent effects (69%) on benthic assemblages, mostly on account of regional natural characteristics (30%) and RHQ features (31%). As benthic invertebrate assemblages are adapted to the former natural conditions, a similar modification may result in different effects with regard to regional natural differences. Therefore, the low proportion of variability, explained by RHM features, might be the consequence of joint dataset from different regions. Our study gives general implications for river management, but in order to more clearly define the significance of particular modification features, we suggest further analysis within more homogeneously defined habitats that encompass regional natural characteristics.
COBISS.SI-ID: 3101263
Due to a long history of human intervention in river ecosystems, pristine conditions hardly exist nowadays and therefore a concept of a "guiding image" defines the present-day potential natural state. Since regional physiographic factors influence the natural habitat features and biota on local level, also guiding images are expected to differ regionally. In this study, the guiding images of rivers of four major regions were defined: alpine, lowland, mediterranean and karst. The habitat features of rivers were studied in four major European regions: the Alps, the Pannonian Lowland, the Submediterranean region and the Dinaric region. For the analysis only those river habitat quality features were used that were proven to be ecologically important. The results showed differences among habitat features of rivers of all investigated regions. On the whole dataset the major gradient among reference sites was observed for habitat features that are in tight relation to water flow and sediment dynamics. For these features the major differences were found between the alpine and the lowland rivers, and on the other hand the similarities were observed between the Mediterranean and the Alpine rivers and between the karst and the lowland rivers. Another important gradient was observed on account of habitat features of riparian and channel vegetation. The highest values of these features were observed for the alpine and the mediterranean rivers and lower in the karst or the lowland rivers. However, the simpler riparian vegetation structure suggested by our results might not be the representative picture of natural vegetation, so the values of these features for a guiding image should be used with caution. In the present study the first step to the guiding images of the rivers in four major regions is proposed. Since the results showed considerable variability of some river habitat features present within regions, we suggest further investigation on even smaller groups. Nevertheless, the recognized differences and similarities among four regions in river habitat features that are ecologically relevant might serve as guidance for more sustainable and cost-effective river management.
COBISS.SI-ID: 7024481
In May 2014, extreme floods occurred in the lower Sava River basin, causing major damage, with catastrophic consequences. Based on the data gathered, the weather situation in Bosnia and Herzegovina's (BiH) Bosna River basin was analysed and the hydrological conditions were provided, including the results of the probability analysis of the size of the recorded precipitation and flow rates. According to the observed data, extremely high precipitation intensities produced specific discharges of 1.0%m3%s%1%km%2. A hydrological model of the Bosna River basin was developed using HBV light for the purposes of reconstructing and forecasting such events more effectively. All analyses confirmed that the May 2014 event was an extreme extraordinary event whose return period greatly exceeds 100 years. The study is the basis for further flood safety measures and flood forecast development in the Bosna River basin.
COBISS.SI-ID: 7952737