The thesis deals with the status assessment of the stream in urban areas. The study area is the stream Rokytka in Prague. The method Hydroecological monitoring HEM (Langhammer, 2007, 2013) was used for the thesis based on field hydromorphological survey. This method is compatible with the Water Framework Directive 2000/60/EC. The thesis also includes assessement of the rainoff regime and water quality based on the available hydrological and hydrochemical data. As a final result, it was found out the stream Rokytka achieves III. hydromophological state - average state. The water quality state does not meet the requirements of the environmental standards quality. In the urban landscape, it is necessary to find a suitable compromise between flood protection and good environmental conditions. Powered by TCPDF (www.tcpdf.org)

Les cours d’eau et leurs bassins versants sont des systèmes complexes et en équilibre dynamique. Si l’on connait qualitativement assez bien la plupart des processus dont ils sont le siège (ex. transport de matière organique et de sédiments, transformation des litières, etc…), il est beaucoup plus difficile d’en avoir une représentation pertinente à la bonne maille compte tenu de l’emboitement d’échelles des processus, des déterminants terrestres agissant sur les milieux aquatiques et surtout des différents facteurs de stress qui s’y combinent. Nous avons mené une exploration dont le but était de rechercher les causes souvent multiples de dégradation de l’état écologique, d’en connaître l’étendue spatiale et la gravité, pour être en mesure de recommander des actions efficaces de restauration. Dans la première partie de cette thèse, nous avons développé des modèles explicatifs de l’état écologique à large échelle capables de donner des réponses applicables aux échelles de décision et de gestion, à savoir européenne, nationale et régionale avec comme objectif principal de comparer les relations entre les pressions combinées représentées par l’occupation du sol et l'état écologique des cours d’eau de quatre pays européens: la France, la Slovaquie, l'Estonie, et le Royaume-Uni (Angleterre et Pays de Galles). Cette étude a permis (i) d’établir une hiérarchie des catégories d’occupation du sol influant sur l'état écologique, en particulier l'agriculture et l'urbanisation, (ii) d’identifier des tendances régionales dans ces relations pression-impact et (iii) d’évaluer le poids relatif de la pression à l‘échelle du bassin et du corridor rivulaire, et l’effet tampon des zones rivulaires suivant la nature de leur couverture. Dans une deuxième partie, nous avons construit un corpus de modèles capables d’expliquer d’une part la variabilité des indices biologiques utilisés dans les réseaux et de prédire d’autre part l’état écologique des masses d’eau françaises non suivies par le réseau de contrôle et de surveillance (RCS). Cette étude a permis de montrer que : (i) le facteur le plus impactant pour l’état biologique qu’il soit mesuré à partir des macroinvertébrés, des poissons ou des diatomées était la physico-chimie, suivie de l’occupation du sol et de l’hydromorphologie et (ii) l’utilisation de ces trois types de pressions permettait de développer des modèles prédictifs de l’état biologique robustes et fiables. Dans une troisième partie, nous avons voulu tester si les relations entre les pressions à l'échelle locale et l'état écologique étaient hiérarchiquement influencées par la typologie régionale (basée sur les caractéristiques géographiques naturelles et les forces motrices). Ceci nous a permis de montrer que la prise en compte d’une typologie basée sur les forces motrices des bassins versants ne remettait pas en cause la hiérarchie des effets des pressions sur la biologie. Enfin, dans une quatrième et dernière partie, nous avons développé une approche nouvelle qui propose de prendre en compte les connaissances sur l’organisation des échelles et sur les liens entre pressions et état écologique, en construisant et en analysant un modèle structurel qui a permis de relier entre elles des variables latentes correspondant aux pressions d’occupation du sol, hydromorphologiques et physico-chimiques et d’analyser in fine leur effet sur l’état écologique mesuré ici à travers l’I2M2. Le développement de ce modèle a montré : (i) l’effet important de l’occupation du sol sur l’hydromorphologie et sur la physico-chimie et l’effet indirect qui en découle sur les macroinvertébrés, (ii) l’effet de l’hydromorphologie sur la mosaïque de substrats, la dynamique des nutriments et de la matière organique, impliquant un effet indirect majeur sur les macroinvertébrés / The rivers and their watersheds are complex systems in dynamic balance. If processes acting in stream are relatively well known (organic matter and sediment transport, litter degradation, etc ...), it is much more difficult to have a relevant representation of this functioning considering the hierarchy of scales, land determinants affecting aquatic environments and combined multiple stressors. We conducted an exploration whose purpose was to seek the multiple causes of degradation of the ecological status, to know the spatial extent and severity and to be able to recommend effective restoration actions. In the first part of the thesis, we developed large-scale models, based on existing data, to give answers applicable to the decision and management scales, i.e. European, national and regional. The main was to compare the relationships between the combined pressures represented by land cover and the ecological status of running waters in four European countries: France, Slovakia, Estonia, and UK (England and Wales). This first study allowed us i) to establish the hierarchy of the major influences that impact ecological status, particularly agriculture and urbanisation, ii) to identify regional patterns in these pressure-impact relationships and iii) to evaluate the relative weight of the pressures acting at the basin and riparian corridor scales, and the possible buffering effect of riparian land cover. In the second part of the thesis, we built a corpus of models capable of explaining the variability of the biological indices used in the survey network and also predict the ecological status of non-monitored water bodies in France. This permits to demonstrate that : (i) the parameters characterizing the load of nutrients and organic matter had a predominant effect on the three compartments, followed by land use and hydromorphology, (ii) it is possible to build models capable of predicting ecological status that are efficient and easily transferable, using data of different scales that influence the functioning of hydrosystems. In the third part, we tested if the relationships between local scale pressures and ecological status are hierarchically influenced by regional patterns (such as natural physiographic and/or driving forces). Introducing hierarchical factors in multi-stress models can lead to slight variations in responses of organisms to pressures according to their natural characteristics and their driving forces acting at catchment scale. And in the last part, the purpose of our approach was to take into account the nested scale organisation and the links between anthropogenic pressures and river ecological status by building - and analysing the results of - a model based on the PLS path modelling method. This method can be used to simultaneously analyse the effects of latent variables corresponding to land-use, hydromorphological and physico-chemical pressures on the ecological status of rivers, synthetically measured in this study by the macroinvertebrate-based French biotic index for wadeable rivers (I2M2). The development of this model should allow us to demonstrate : (i) the importance of land use effect exerted on both hydromorphology and physico-chemistry and their translation as an indirect effect on biological condition of streams, (ii) that hydromorphological alterations had an effect on substrates structure and nutrients and organic matter concentrations implying that hydromorphology has a major indirect effect on macroinverteb

This thesis deals with the retention capacity of Berounka during the hydrological extremes. Flood prevention and flood condition are main subjects of this thesis. Two selected river areas of Berounka are analysed by the passive retention volume and by the transformation of the flood wave. The first area is situated on the lower course of Berounka near the Černošice, and this area is significantly anthropogenically influenced. The second area which has nature character is located on the middle course of Berounka near Křivoklát. This thesis contains an evaluation of the hydromorphological state of flow in both areas. The results of passive retention indicate negligible influence of the flood situations. 1D hydraulic model HEC-RAS displays the transformation of the flood wave. The results of the transformation are flow velocity and depths of the river valley in 100-year-old and 20-year-old flows. The transformation of the flood wave in the first area is on the minimum level and did not reach its potential retention capability. The culmination flow in the second area is reduced because of a geomorphological shape of the river. Moreover, the near natural flood protection precautions are proposed in this thesis. Mean flow velocity in 100-year floods could be reduced by 1 - 1,6 m.s-1 by forestation of...

Les rapports entre sociétés et rivières sont marqués par des bouleversements environnementaux qui interrogent les modalités, plus ou moins institutionnalisées et systématisées, de la production de connaissances et de la définition de pratiques légitimes. Récemment, ces interpellations se sont affirmées et cristallisées autour de l’approche et des concepts portés par l’hydromorphologie. La plus grande considération de ce cadrage théorique au sein de modes de penser et d’agir engendre de nombreux remaniements. En découle notamment, la remise en question d’une gestion des cours d’eau basée sur leur maîtrise et leur stabilisation, au profit d’une approche privilégiant l’expression de la dynamique fluviale. Cette thèse propose un examen de la dynamique qui a permis d’ériger l’hydromorphologie en une préoccupation formalisée et prépondérante. Puis, elle s’attache à montrer, comment l’hydromorphologie traduit les évolutions des rapports entre sociétés et rivières au travers de trajectoires conjointes marquées par des pratiques, des matérialités et des adaptations réciproques. Elle entend également mettre en avant comment cette nouvelle configuration théorique et pratique perturbe, tout au moins à l’heure actuelle, ce qui paraissait légitime et rationnel, et nécessite une recomposition des valeurs et des intentionnalités que les communautés riveraines manifestent à l’égard des cours d’eau. Cette thèse rend finalement compte de la manière dont l’action publique et ses instruments s’adaptent et s’inventent au regard d’une plus grande prise en compte de l’hydromorphologie afin de tendre vers ce à quoi celle-ci invite : redéfinir les modalités d’une existence conjointe entre rivières et sociétés riveraines. / The relationship between societies and rivers is marked by environmental changes that question the modalities, more or less institutionalized and systematized over time, used to generate knowledge and to define legitimate practices. Recently, these questions have emerged and crystallized around the approach and concepts supported by hydromorphology. The greater consideration of this theoretical framework within ways of thinking and acting leads to many changes. In particular it follows that river management based on the control and stabilization of rivers is challenged in favour of an approach based on the expression of the river dynamics. This thesis proposes, first, a review of the processes which helped made it into a formal and decisive issue. Then the thesis aims to show through how hydromorphology represents and reflects the changes in the relationship between people and rivers through joint trajectories marked by practices, materiality and reciprocal adaptation throughout unique timescales and spatiality. It also intends to highlight, through an analysis of the representations of hydromorphological functioning of the river, how this new theoretical and practical configuration disturbs, at least currently, what seemed legitimate and rational until this day, and requires a restructuring of values and intentionality that riparian communities display in respect of watercourses. Finally, this thesis accounts for how public policy and its instruments are faced with new expectations, both cognitively and operationally, how they adapt and reinvent themselves in the light of a greater consideration of hydromorphology towards what it calls for: redefining the terms of a joint existence between the rivers and riparian societies.

Submitted by Maike Costa (maiksebas@gmail.com) on 2016-01-05T12:09:06Z No. of bitstreams: 1 arquivototal.pdf: 8370454 bytes, checksum: 26479ee704fbe159e1994c81453039fa (MD5) / Made available in DSpace on 2016-01-05T12:09:06Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 8370454 bytes, checksum: 26479ee704fbe159e1994c81453039fa (MD5) Previous issue date: 2014-09-10 / The negative impacts caused by the use of process and land use on the banks of rivers and floodplains have been deteriorating the water health conditions, the environment and effect on landscapes. In urban areas, in particular, it is observed the degradation of rivers and water quality and aquatic biota. The interest in restoring ecosystems of waterways, both in urban and rural areas, is expanding worldwide, especially in developed countries. Similarly, areas of occupation in the coastal zone, those which tend to larger and denser occupation, have been a main concern of many governments. Therefore, models of environmental assessment of rivers have been developed and refined to allow the diagnosis and the selection of river restoration actions. The German method, called Mapping and assessment methods for the structure of Waters, developed in Bavaria, is used to map the quality of watercourses structure as a measure of its ecological integrity and indicates whether it is capable of supporting the dynamic processes of its bed. For the coastal zone, the Orla project’s methodology, developed by the Ministry of Environment of Brazil, uses the landscape units as elements of analysis in terms of urban occupation and provides grants for landscape analysis beyond the river limits and may complement fluvial analysis. Both methodologies contribute to perform a broader diagnosis of the current situation of environmental degradation, and may indicate which stretches and landscape units would need intervention to seek restoration or rehabilitation of these areas. In this work, these models were used to map the quality of the riverbed structure concerning its morphology, including the dynamics of the main river and the dynamics of wetlands, and also the marginal areas of low Jaguaribe River in its bed in the municipalities of João Pessoa and Cabedelo, on the south coast of the state of Paraíba. The results showed stretches of the river ranging from a totally altered state to little changed, concerning the stretch and the side occupation of the river channel. The extended marginal areas were classified into three types A, B, C of the Orla project, showing conformity with the classification obtained from the river system. / Os impactos negativos causados pelo processo de uso e ocupação do solo nas margens e planície de inundação dos rios vêm deteriorando as condições de salubridade das águas, do ambiente e com repercussão nas paisagens. No meio urbano, em particular, se observa a degradação dos rios e da qualidade da água e da biota aquática. O interesse em restabelecer os ecossistemas dos cursos d’água, tanto nas áreas urbanas quanto na rural, está se expandindo em todo o mundo, especialmente nos países desenvolvidos. De forma semelhante, a ocupação de áreas na zona costeira, as que apresentam tendências de maiores e mais densas ocupações, tem sido objeto de preocupação de diversos governos. Assim, modelos para avaliação ambiental de rios têm sido desenvolvidos e aperfeiçoados para permitir o diagnóstico e a seleção de ações de restauração fluvial. O método alemão, denominado Mapping and assessment methods for the structure of Waters, desenvolvido na Bavária, é utilizado para o mapeamento da estrutura da qualidade dos cursos d’água como medida da sua integridade ecológica e indica se o mesmo é capaz de suportar os processos dinâmicos de seu leito. Para a zona costeira, a metodologia do projeto Orla, desenvolvida pelo Ministério do Meio Ambiente do Brasil, se utiliza das unidades de paisagem como elementos de análise em termos de ocupação urbana e oferece subsídios para a análise da paisagem além dos limites fluviais, podendo complementar a análise fluvial. Ambas as metodologias contribuem para se realizar um diagnóstico mais amplo da situação atual de degradação ambiental, e podem indicar em quais trechos e unidades paisagísticas haveria necessidade de intervenção buscando a restauração ou requalificação dessas áreas. Neste trabalho, foram utilizados esses modelos para o mapeamento da estrutura da qualidade do leito fluvial, referente a sua morfologia, compreendendo a dinâmica do rio principal e a dinâmica das várzeas, além das áreas marginais do baixo rio Jaguaribe em seu antigo leito nos municípios de João Pessoa e Cabedelo, na zona costeira Sul do estado da Paraíba. Os resultados apontaram trechos do rio variando do estado totalmente alterado a pouco alterado, segundo o trecho e a ocupação lateral da calha fluvial. As áreas marginais estendidas foram classificadas nas três tipologias A, B, C do projeto Orla, apresentando concordância com à classificação obtida do sistema fluvial.

The final thesis is focused on assessing the current state of hydrological system in the watershed area Jankovice stream and on draft proposal of food protection measures of the village Jankovice. In the first part of the thesis, there is documented the current situation Jankovice stream, its appreciation and draft measures for a improvement the current state. In the following part, there is the elaboration of the sediment transport balance in the stream. In the last part of the final thesis, there is documented the current state Jankovice stream in the village Jankovice and the stream regulation is designed for the purpose of flood protection of the village.

This thesis deals with hydroecological monitoring of watercourses. The HEM – Hydroecological monitoring is part of evaluation of status of watercourses, which is a requirement of the European Water Framework Directive. The content of this thesis is firstly to find out the status monitoring of hydromorphological quality of watercourses in the Czech Republic and a subsequent survey of methodology HEM. The aim of this thesis is comparison with the older methodologies and ways to improve the practical implementation of monitoring on smaller waterways. Measurement and knowledge will be applied to Troubsko creek.

In addition to the hydromorphological pressure on the ecological conditions of free-flowing river courses, increasing water temperature is affecting the water bodies, particularly by changing freshwater community compositions. The low discharge of numerous European rivers in the dry and hot hydrological year 2022 proves this relevance. Therefore, ecological assessment tools such as habitat modeling should take these factors into account when assessing the quantity and quality of habitats. In this paper, the habitat modeling tool “Transient River Habitat Modeling for Macrozoobenthos” (TRiMM) is improved by incorporating a fuzzy logic approach and adding water temperature to the set of parameters determining habitat suitability for macrozoobenthos. Habitat-relevant parameters, including hydromorphological factors (depth, velocity, mineral and organic substrate) and a water quality factor (temperature), are combined in the habitat model so that it can more broadly characterize river physical conditions and their interactions with biological indicators. Habitat modeling employed the mentioned parameters to simulate suitability for the macrozoobenthos in a small river in central Saxony, Germany. Due to its deteriorated condition, this river was selected as a representative for thousands of kilometers of small rivers across the region, which have been restored. The model simulated the status quo of river conditions from spring to summer for three macrozoobenthos species (Ancylus fluviatilis, Ephemera danica and Gammarus fossarum). The results showed that the natural flow resulted in dynamic habitat suitability both spatially and temporally, which differs for each species. Remarkably, the five-parameter model (depth, velocity, temperature, mineral, and organic substrate) generally performed better compared to a similar model without temperature.

Rivers and their catchments are under mounting pressure from direct channel modification, intensification of land use, and from a legacy of decades of channelisation. Recent legislation, in the form of the EU Water Framework Directive, places a greater emphasis on the management of water bodies as holistic systems, and includes the explicit consideration of hydromorphological quality, which describes the hydrologic and geomorphic elements of river habitats. These are defined specifically as hydrological regime, river continuity and river morphology. This appreciates that sediment and flow regimes, along with the channel structure, provides the 'template' on which stream ecological structure and function is built. Invertebrate fauna contribute significantly to the biodiversity of rivers, and often form the basis of monitoring river health. However much of the fundamental ecological knowledge base on the response of invertebrates to hydromorphological change needed to make informed decisions and accurate predictions, is either lacking, inadequate or contradictory. This thesis addresses some of the key potential shortcomings in recent bio-assessment that others have alluded to, but which have rarely been explored in the context of direct channel manipulations. By using two case studies of, realignment in a natural upland catchment, and flood protection engineering in an urban stream, this study investigates the sensitivity of hydromorphological impact assessment methods that rely on biodiversity patterns of benthic riverfly (Ephemeroptera, Plecoptera and Trichoptera) larva. This work employed widely used biomonitoring indices of benthic riverfly larva abundance, species richness, alpha and beta diversity, and community composition, applied over a range of spatial scales, in combination with spatially contemporaneous physical habitat data, to describe and explain community changes in response to disturbance, and patterns of natural variation. The effects of restoration were investigated using a high degree of sample replication within channels and across the wider catchment, as well as contrasting spring and autumn seasons. To assess change in a small urban channel, approaches that explicitly consider spatial elements of community data, using spatial eigenvectors analysis, were applied to spatially detrend community data and directly investigate spatial patterns. Restoration of the Rottal Burn was found to be successful in restoring habitat diversity and geomorphic processes, and in turn increasing reach scale species richness and beta diversity through the gradual arrival of rare and specialist taxa into novel habitats. Catchment scale replication revealed high variation in diversity indices of modified and undisturbed streams, and a strong temporal pattern related to antecedent flow conditions. Channels with greater habitat heterogeneity were able to maintain high gamma diversity during times of high flow stress by providing a number of low flow refuges along their length. The urban Brox Burn had surprisingly high riverfly richness and diversity driven by small scale hydraulic heterogeneity, created by bed roughness resulting in a range of microhabitats. Riverfly community responses to direct channel dredging could not be detected by measurements of average richness and diversity, however distinct changes were seen in gamma diversity, the identity of community members and their arrangement among sample patches. Impacts of sediment pollution release due to engineering were short lived and apparently had little detrimental impact on biodiversity. Strong spatial patterns of community assembly on the stream bed were uncovered, relating to longitudinal, edge and patchy patterns. Significant habitat drivers of community composition were confounded by high amounts of spatial autocorrelation, especially hydraulic variables. Due to the strongly physical and spatial nature of hydromorphological disturbance, turnover of species between sample locations at a range of scales, and the spatial arrangement of habitats and communities is of more use for detecting these types of subtle changes compared to mean richness or diversity. These findings have implications for the targeting of resources for monitoring of restoration, or engineering disturbances, in order to be sensitive to hydromorphological change. Efforts should target the main area of natural variability within the system, either replicating sampling in time or space to distinguish effects of impact. Spatial patterns, measures of beta diversity and species identity can be better exploited to identify systems with functioning geomorphological processes. Channel typologies proved misleading, and quantification of habitat and selection of control sites using multiple pre-defined criteria should be carried out. Studies of restoration operations and engineering impacts provide considerable opportunities for advancing our knowledge of the mechanisms that drive community response under a range of conditions to improve impact detection.

Abstract Streams and rivers have been extensively altered by humans. Channelization and land use have changed stream habitats and water quality with adverse effects on biota and ecosystem functions. Impacted streams have been targets for restoration, but there is considerable lack of understanding how streams should be restored in an ecologically effective way. In this doctoral thesis, I studied the impacts of channelization (for timber floating) and agricultural diffuse pollution on stream biota. I also studied the effectiveness of restorations of forestry impacted streams stressed by excessive sand sedimentation from catchment drainage. Finally, I also studied the effects of mosses, fine sediment and enhanced dispersal on stream macroinvertebrate communities and ecosystem functions. I found that channelization did not have effect on diatom, macrophyte, macroinvertebrate and fish assemblages, whereas diffuse pollution had strong effects, with no interactions between the two stressors. I showed that excessive sedimentation from forest drainage was harmful for stream biota but had no effect on leaf decomposition and algal accrual rate. Restoration with boulders reduced sand cover and was more beneficial for in-stream biodiversity, whereas restoration with wood tended to increase hydrological retention of stream channels, thereby altering riparian plant assemblages toward more natural composition. In a mesocosm experiment, I found mosses to have a strong impact on macroinvertebrate communities and ecosystem functions. Mosses increased organic matter retention and reduced algal accrual rate and leaf decomposition. The effect of mosses on macroinvertebrates was stronger than that of sand sedimentation, and mosses mitigated some of the negative effects of sand. Extensive dispersal had a distinct imprint on invertebrate community composition but did not blur the effect of mosses and sand on communities, suggesting strong local-scale environmental control of composition. My thesis emphasizes that priority in stream restoration should be in the mitigation of diffuse pollution rather than restoration of channel morphology, especially in streams where channel alteration has been fairly modest, as in the case of timber floating. Addition of both boulders and large wood likely yields the best biodiversity response in the restoration of forestry impacted streams. Mosses are a key component of boreal lotic ecosystems; therefore, the recovery of mosses may be a prerequisite for the full recovery of biodiversity and ecosystem integrity of boreal streams. / Tiivistelmä Ihmisen toiminta on laajasti muokannut virtavesiä. Uomien kanavointi ja maankäyttö ovat muuttaneet virtavesien elinympäristöjä ja veden laatua, millä on ollut haitallisia vaikutuksia virtavesien luonnon monimuotoisuuteen ja ekosysteemin toimintaan. Huonokuntoisia virtavesiä on kunnostettu paljon, mutta ymmärrys siitä, kuinka virtavesiä tulisi kunnostaa parhaan ekologisen lopputuloksen saavuttamiseksi, on edelleen vajaata. Tutkin tässä väitöskirjassa uittoperkausten ja maatalouden hajakuormituksen merkitystä ja yhteisvaikutusta virtavesien eliöyhteisöihin. Tutkin myös kunnostusten vaikutusta hiekasta kärsivissä metsätalouden muokkaamissa puroissa, sekä vesisammalten, hiekan ja eliöiden levittäytymisen merkitystä purojen pohjaeläinyhteisöjen ja ekosysteemin toimintojen muovautumisessa. Havaitsin, että uoman perkauksilla ei ollut vaikutusta virtavesien eliöyhteisöihin, mutta hajakuormituksen vaikutus oli voimakas. Perkauksella ja hajakuormituksella ei ollut yhteisvaikutuksia eliöyhteisöihin. Osoitin, että metsäojituksista aiheutuva ylimääräinen hiekan sedimentaatio on haitallista virtavesien eliöille, mutta sillä ei ollut vaikutusta lehtikarikkeen hajotukseen tai päällyslevien tuotantoon. Kunnostukset joissa käytettiin kiveä vähensivät hiekan peittävyyttä ja olivat hyödyllisempiä uoman eliöstölle kuin kunnostukset, joissa tehtiin puurakennelmia. Puukunnostukset kuitenkin lisäsivät uoman vedenpidätyskykyä ja siten muokkasivat rantavyöhykkeen kasvillisuutta luonnontilaisemmaksi. Havaitsin, että vesisammalilla on voimakas vaikutus pohjaeläinyhteisöjen koostumukseen. Sammalet vaikuttivat ekosysteemin toimintoihin lisäämällä eloperäisen aineksen pidättymistä ja vähentämällä lehtikarikkeen hajotusta ja päällyslevien tuotantoa. Sammalten vaikutus pohjaeläimiin oli voimakkaampi kuin hiekan, ja sammalet kykenivät jopa lieventämään joitakin hiekan negatiivisia vaikutuksia. Eliöiden levittäytymisellä oli selvä vaikutus yhteisöjen koostumukseen, mutta se ei hävittänyt hiekan ja sammalen vaikutusta, mikä viittaa korkeaan ympäristötekijöiden merkitykseen yhteisöjen rakentumisessa. Tutkielmani korostaa, että maatalousjokien tilan parantamisessa hajakuormituksen hallinta tulisi olla ensisijainen kunnostustavoite uoman rakenteen kunnostamisen sijaan. Metsätalouden vaikutuksista kärsivissä puroissa kivi- ja puumateriaalin käyttö samanaikaisesti tuottaa luultavimmin laajimman vaikutuksen purojen monimuotoisuuteen. Sammalilla on merkittävä vaikutus muiden eliöiden yhteisökoostumukseen ja ekosysteemin toimintoihin, joten sammalten palautuminen on tärkeä kunnostustavoite virtavesissä, joissa on luonnostaan paljon sammalkasvustoa.