Development of a River Macrophyte Index (RMI) for assessing river ecological status

AbstractWe present the process of developing a macrophyte based index (River Macrophyte Index – RMI) for assessing river ecological status, that would be applicable for rivers with moderate to high water alkalinity, flowing over low slope terrain. A reference value and boundary values were determined for five ecological classes. The relation between the developed index and two existing indices, the Reference Index (RI) and the Trophic Index of Macrophytes (TIM), and selected environmental variables was established. The RMI is based on species composition and abundance from 208 sampling sites being in reference or good hydromorphological conditions and differing in the catchment land use. The percentage of natural areas in the sub-catchment was used for classifying macrophyte taxa into 5 ecological groups. 65 plant taxa, of which 47 were identified as indicator taxa, were included in the analysis. To assess the ecological status of a river site, the presence of at least 3 indicator taxa is necessary, otherwise the assessment is considered inconclusive. RMI is expected to indicate multiple pressures on the river, including trophic level. The developed index and RI and TIM indices differed in relation to slope, distance to source and catchment size

Riparian Zones—From Policy Neglected to Policy Integrated

1. Riparian zones are vital areas of interaction between land and rivers and are often degraded by several pressures such as urbanisation, intensive agriculture and river engineering works. 2. This policy brief provides five key policy messages and recommendations to be considered by policy-makers, scientists, managers, and stakeholders to enhance riparian zone management. 3. Adopting an integrated socioeconomic and environmentally dynamic view will ensure the sustainable management of riparian zones. 4. In light of climate change, it is critically important to conserve and/or restore the ecological integrity of riparian zones. 5. European Union Directives and national-scale legislation and regulations need updating to ensure coordinated implementation of riparian zone-related policies. 6. Stakeholder knowledge exchange, policy co-creation and adaptive management are key to enhancing riparian zone functions

Defining Chlorophyll-a Reference Conditions in European Lakes

The concept of “reference conditions” describes the benchmark against which current conditions are compared when assessing the status of water bodies. In this paper we focus on the establishment of reference conditions for European lakes according to a phytoplankton biomass indicator—the concentration of chlorophyll-a. A mostly spatial approach (selection of existing lakes with no or minor human impact) was used to set the reference conditions for chlorophyll-a values, supplemented by historical data, paleolimnological investigations and modelling. The work resulted in definition of reference conditions and the boundary between “high” and “good” status for 15 main lake types and five ecoregions of Europe: Alpine, Atlantic, Central/Baltic, Mediterranean, and Northern. Additionally, empirical models were developed for estimating site-specific reference chlorophyll-a concentrations from a set of potential predictor variables. The results were recently formulated into the EU legislation, marking the first attempt in international water policy to move from chemical quality standards to ecological quality targets

Inland water subecoregions and bioregions of Slovenia

The main objective of our work was to carry out the division of inland water ecoregions - hydroecoregions of Slovenia and to define inland water subecoregions - subhydroecoregions, bioregions and large rivers. A two-stage approach was used. Initially, a division was performed using thematic maps. During the second step, a priori division was checked using biological data. Historical fish data, and benthic invertebrate data collected at reference andslightly impacted sites were used. A statistical analysis of non-metric multidimensional scaling was performed to test a priori divisions. The Alps hydroecoregion was divided in two subhydroecoregions: the Alps-Danube river basin and Alps-Adriatic river basin. The Dinarids hydroecoregion was also divided in two subhydroecoregions: the Eudinaric and Sub-Mediterranean. Hydroecoregions and subhydroecoregions were divided into 16 bioregions and 9 types of large rivers. In the Dinarids hydroecoregion, seven bioregions were defined, in the Alps hydroecoregion five bioregions, in the Pannonian lowland hydroecoregion three bioregions, whereas the Po lowland hydroecoregion was notfurther divided and has only one bioregion in Slovenia. Main abiotic differences among bioregions beside river basin are also dominant geology, maximum altitude classes and altitude classes of the influence area

Novi podatki iz družine hydroptilidae v favni mladoletnic (Trichoptera) Slovenije

A list of fourteen new Hydroptilidae records for the Slovenian caddisfy fauna is given. Genera Agraylea and Stactobia were recorded for the first time in Slovenia. Hydroptila rheni Ris 1903 has been previously known only from a typelocality in Switzerland. The number of recorded Slovenian caddisfly species has thus increased to 238.Naveden je seznam štirinajst novih vrst družine Hydroptilidae v favni Slovenije. Rodova Agraylea in Stactobia sta bila ugotovljena v Sloveniji prvič. Vrsta Hydroptila rheni Ris 1903 je bila pred tem najdena samo na tipskilokaliteti v Švici. Število vrst mladoletnic, najdenih v Sloveniji, je naraslo na 238

Hydromorphological degradation impact on benthic invertebrates in large rivers in Slovenia

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

Responses of Freshwater Diatoms and Macrophytes Rely on the Stressor Gradient Length across the River Systems

Phytobenthic diatoms and macrophyte communities respond differently to stressors in aquatic environments. For the assessment of the ecological status of rivers in Slovenia, we use several indices, including the River Macrophyte Index (RMI) and Trophic index (TI) based on macrophyte and phytobenthic diatoms communities, respectively. In the present study, we examined the relationships between nutrient variables and values of RMI and TI using varied stressor gradient lengths. We also aimed to explain the variability of macrophyte and diatom communities with different stressors, namely nutrients and land cover variables and their combinations. The relationships of RMI and TI with nutrient variables varied significantly and were affected by the length of the stressor gradient. We obtained a stronger relationship between the RMI and total phosphorous at an approximately <0.3-mg/L annual mean value, while, for the relationships with the TI, the values were significant at bigger gradient lengths. The greatest share of variability in the macrophyte and diatom community was explained by the combination of land use and nutrient variables and the lowest share by phosphorus and nitrogen variables. When we applied a composite stressor gradient, it explained a similar share of the variability of both macrophyte and diatom communities (up to 26%). A principal component analysis (PCA) based on land use and nutrient stressor gradient revealed that the relationship between RMI EQR and PCA1 that represents intensive agriculture depends on the length of the gradient. The relationship was stronger for shorter gradients at lower values and decreased as the gradient extended towards higher values. Both tested assessment methods showed that macrophyte communities are more sensitive to shorter stressor gradients of lower values, whereas diatom communities are more sensitive to longer stressor gradient and higher values of the stressor