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Riparian Ecological Infrastructures are networks of natural and semi-natural riparian areas located in human-dominated landscapes, crucial in supporting processes that directly or indirectly benefit humans or enhance social welfare. In this study, we developed a novel multimetric index, termed Habitat Ecological Infrastructure’s Diversity Index (HEIDI), to quantify the potential of Riparian Ecological Infrastructures in supporting biodiversity, and related ecosystem services, in three managed landscapes: Intensive Agriculture, Extensive Agriculture, and Forest Production. Metrics describing the structure, composition, and management of riparian vegetation and associated habitats were used to derive the potential of Riparian Ecological Infrastructures in supporting three distinct biological dispersal groups: short-range dispersers (ants), medium-range dispersers (pollinators), and long-range dispersers (birds, bats, and non-flying small mammals). The composition of floristic resources, assessed by identifying trees and shrubs at the species and genus level, and herbaceous plants at the family level, was used as a proxy to evaluate the potential of Riparian Ecological Infrastructures in promoting seed dispersal and pollination ecosystem services provided by the three biological communities. Our research evidenced that Riparian Ecological Infrastructures located in the Forest Production and Intensive Agriculture landscapes exhibited the highest and lowest potential for biodiversity-related ecosystem services, respectively. The Forest Production landscape revealed higher suitability of forage resources for short- and medium-range dispersers and a higher landscape coverage by Riparian Ecological Infrastructures, resulting in more potential to create ecological corridors and to provide ecosystem services. The Riparian Ecological Infrastructures located in the Extensive Agriculture landscape seemed to be particularly relevant for supporting long-ranges dispersers, despite providing less habitat for the biological communities. Land-use systems in the proximity of Riparian Ecological Infrastructures should be sustainably managed to promote riparian vegetation composition and structural quality, as well as the riparian width, safeguarding biodiversity, and the sustainable provision of biodiversity-related ecosystem services info:eu-repo/semantics/publishedVersion

This work assesses the effects of river regulation on the diversity of different instream and riparian biological communities along a relieve gradient of disturbance in regulated rivers. Two case studies in Portugal were used, with different river regulation typology (downstream of run-of-river and reservoir dams), where regulated and free-flowing river stretches were surveyed for riparian vegetation, macrophytes, bryophytes, macroalgae, diatoms and macroinvertebrates. The assessment of the regulation effects on biological communities was approached by both biological and functional diversity analysis. Results of this investigation endorse river regulation as a major factor differentiating fluvial biological communities through an artificial environmental filtering that governs species assemblages by accentuating species traits related to river regulation tolerance. Communities' response to regulation gradient seem to be similar and insensitive to river regulation typology. Biological communities respond to this regulation gradient with different sensibilities and rates of response, with riparian vegetation and macroinvertebrates being the most responsive to river regulation and its gradient. Richness appears to be the best indicator for general fluvial ecological quality facing river regulation. Nevertheless, there are high correlations between the biological and functional diversity indices of different biological groups, which denotes biological connections indicative of a cascade of effects leading to an indirect influence of river regulation even on non-responsive facets of communities' biological and functional diversities. These results highlight the necessary holistic perspective of the fluvial system when assessing the effects of river regulation and the proposal of restoration measures. published

Eighty-six percent of the largest Portuguese public forest, Leiria National Forest (Mata Nacional de Leiria—MNL), central west, was burned in a wildfire in October 2017. Most of the area was covered by maritime pine stands (Pinus pinaster Aiton) crossed by riparian forests along small-sized streams. This work aims to characterize the post-fire vegetation and evaluate its natural regeneration. Sampling was carried out c. 6 months after the fire in 28 plots distributed at pine stands (3.5 × 3.5 m2) and in 24 plots (5 × 20 m2) at stream channels and riverbanks. These latter surveys were repeated in 2019. Data include the floristic composition and cover data of pine stands and streams, and the number of pine seedlings. Six months after the fire, 60% and 93% of the pre-fire species were observed at streams and pine stands, respectively. Fire severity was not related to differences in flora composition, nor with species richness. Pine seedlings were significantly more abundant in pine stands &gt, 60 years old compared to younger (&lt, 25 y) stands, but no significant differences were observed in the regeneration of understory. On riparian landscapes, the germination and resprouting of invasive exotic species, such as Acacia sp., created dense vegetation formations with decreased native plant diversity and altered the ecosystem structure. Following large wildfires, such as the one in MNL, managers should prioritize preserving the natural regeneration potential in the soil and aerial seed banks.

Review The biological assessment of rivers i.e., their assessment through use of aquatic assemblages, integrates the effects of multiple-stressors on these systems over time and is essential to evaluate ecosystem condition and establish recovery measures. It has been undertaken in many countries since the 1990s, but not globally. And where national or multi-national monitoring networks have gathered large amounts of data, the poor water body classifications have not necessarily resulted in the rehabilitation of rivers. Thus, here we aimed to identify major gaps in the biological assessment and rehabilitation of rivers worldwide by focusing on the best examples in Asia, Europe, Oceania, and North, Central, and South America. Our study showed that it is not possible so far to draw a world map of the ecological quality of rivers. Biological assessment of rivers and streams is only implemented officially nation-wide and regularly in the European Union, Japan, Republic of Korea, South Africa, and the USA. In Australia, Canada, China, New Zealand, and Singapore it has been implemented officially at the state/province level (in some cases using common protocols) or in major catchments or even only once at the national level to define reference conditions (Australia). In other cases, biological monitoring is driven by a specific problem, impact assessments, water licenses, or the need to rehabilitate a river or a river section (as in Brazil, South Korea, China, Canada, Japan, Australia). In some countries monitoring programs have only been explored by research teams mostly at the catchment or local level (e.g., Brazil, Mexico, Chile, China, India, Malaysia, Thailand, Vietnam) or implemented by citizen science groups (e.g., Southern Africa, Gambia, East Africa, Australia, Brazil, Canada). The existing large-extent assessments show a striking loss of biodiversity in the last 2–3 decades in Japanese and New Zealand rivers (e.g., 42% and 70% of fish species threatened or endangered, respectively). A poor condition (below Good condition) exists in 25% of South Korean rivers, half of the European water bodies, and 44% of USA rivers, while in Australia 30% of the reaches sampled were significantly impaired in 2006. Regarding river rehabilitation, the greatest implementation has occurred in North America, Australia, Northern Europe, Japan, Singapore, and the Republic of Korea. Most rehabilitation measures have been related to improving water quality and river connectivity for fish or the improvement of riparian vegetation. The limited extent of most rehabilitation measures (i.e., not considering the entire catchment) often constrains the improvement of biological condition. Yet, many rehabilitation projects also lack pre-and/or post-monitoring of ecological condition, which prevents assessing the success and shortcomings of the recovery measures. Economic constraints are the most cited limitation for implementing monitoring programs and rehabilitation actions, followed by technical limitations, limited knowledge of the fauna and flora and their life-history traits (especially in Africa, South America and Mexico), and poor awareness by decision-makers. On the other hand, citizen involvement is recognized as key to the success and sustainability of rehabilitation projects. Thus, establishing rehabilitation needs, defining clear goals, tracking progress towards achieving them, and involving local populations and stakeholders are key recommendations for rehabilitation projects (Table 1). Large-extent and long-term monitoring programs are also essential to provide a realistic overview of the condition of rivers worldwide. Soon, the use of DNA biological samples and eDNA to investigate aquatic diversity could contribute to reducing costs and thus increase monitoring efforts and a more complete assessment of biodiversity. Finally, we propose developing transcontinental teams to elaborate and improve technical guidelines for implementing biological monitoring programs and river rehabilitation and establishing common financial and technical frameworks for managing international catchments. We also recommend providing such expert teams through the United Nations Environment Program to aid the extension of biomonitoring, bioassessment, and river rehabilitation knowledge globally info:eu-repo/semantics/publishedVersion

Dam-induced disruption of the natural continuum of rivers has manifold consequences on fluvial ecosystems, but how distinct plant groups and plant adaptive strategies can mediate the regulation effects is largely unexplored. In this work, we focused on how different plant groups (macrophytes, bryophytes, and riparian woody vegetation) respond to hydrological alterations along the river and across the riparian zone downstream of dams. We specifically aimed to determine the degree of regulation [DOR] and distance from dam [DFD], where river regulation no longer significantly affects plant communities in two case studies – a run-of-river dam and a reservoir in Portugal. We collected data on plant species cover in 7 unregulated and 24 regulated sites in June–July 2019. We performed a cluster and ordination analysis to derive guilds using flow-responsive traits and applied linear models to predict guild alterations along the gradient of DOR and DFD. We established three macrophytes, six bryophytes, and five riparian guilds. Our results showed that the vegetation response to regulation was plant group-reliant and guild-specific. Overall, plant responses were expressed by changes in plant cover, and not by guilds' loss. We observed (1) an increase of the guild cover of macrophytes and a decrease in bryophytes cover with increasing regulation gradient and diverse responses for riparian guilds; (2) an encroachment of riparian vegetation guilds into the channel downstream of the storage reservoir and expansion outwards downstream of the run-of-river dam; (3) a higher number of significant alterations for reservoir sites compared with run-of-river sites. Finally, for particular guilds, we determined specific DOR and DFD from which guild covers became significantly indistinct from respective guild cover in unregulated circumstances. Understanding the communities' responses to diverse regulation types and the extent that different plant adaptations may counter regulation effects can be vital for optimizing river restoration projects.

Fluvial riparian vegetation (RV) links fluvial and terrestrial ecosystems. It is under significant pressure from anthropogenic activities, and, therefore, the management and restoration of RV are increasingly important worldwide. RV has been investigated from different perspectives, so knowledge on its structure and function is widely distributed. An important step forward is to convert existing knowledge into an overview easily accessible—for example, for use in decision-making and management. We aim to provide an overview of ecosystem services provided by RV by adopting a structured approach to identify the ecosystem services, describe their characteristics, and rank the importance of each service. We evaluate each service within four main riparian vegetation types adopting a global perspective to derive a broad concept. Subsequently, we introduce a guided framework for use in RV management based on our structured approach. We also identify knowledge gaps and evaluate the opportunities an ecosystem service approach offers to RV management.

Major threats of freshwater systems are river damming and habitat degradation, further amplified by climate change, another major driver of biodiversity loss. This study aims to understand the effects of climate change, and its repercussions on hydropower production, on the instream biota of a regulated river. Particularly, it aims to ascertain how mesohabitat availability downstream of hydropower plants changes due to modified flow regimes driven by climate change; how mesohabitat changes will influence the instream biota; and if instream biota changes will be similar within and between biological groups. We used a mesohabitat-level ecohydraulic approach with four biological elements – macrophytes, macroalgae, diatoms and macroinvertebrates – to encompass a holistic ecosystem perspective of the river system. The ecological preferences of the biological groups for specific mesohabitats were established by field survey. The mesohabitat availability in three expected climate change-driven flow regime scenarios was determined by hydrodynamic modeling. The biota abundance/cover was computed for the mesohabitat indicator species of each biological group. Results show that climate-changed flow regimes are characterized by a significant water shortage during summer months already for 2050. Accordingly, the regulated rivers' hydraulics are expected to change towards more homogeneous flow conditions where run habitats should prevail. As a result, the biological elements are expected to face abundance/cover modifications ranging from decreases of 76% up to 67% increase, depending on the biological element and indicator taxa. Diatoms seem to endure the greatest range of modifications while macrophytes the slightest (15% decrease to 38% increase). The greatest modifications would occur on decreasing abundance/cover responses. Such underlies an important risk to fluvial biodiversity in the future, indicting climate change as a significant threat to the fluvial system in regulated rivers.

Measures of functional diversity are increasingly being used in ecological research to understand and predict vegetation ecosystem changes. However, there is currently no summary of how, why and where these indicators have been used in riparian forest studies around the world. The present article addresses the key concepts and their evolution across time and reviews the relevance of the use and application of functional trait-based approaches in riparian forests in the last two decades (1997–2017; 70 SCI articles). Our overview contains five sections: I. Evolution of concepts, applications, and methods; II. Functional diversity measures: application in riparian forests; III. Plant functional traits: which traits, how many and why; IV. Functional diversity responses and drivers of change; and V. Future research directions. It would appear that the advances in functional diversity frameworks in the last 20 years have led to an increase in the number of studies using riparian plant guilds and functional diversity indices, with a widespread distribution across Europe and the USA. The use of easily measurable (‘soft’) traits is more prevalent than that of ‘hard traits’ consisting of direct measurements of individual processes. Specific Leaf Area (SLA), plant height, and seed mass were the most common traits used in riparian studies. The number of traits per case study varied greatly, ranging from 1 to 36 traits (median = 6), most of which were selected with the goal of describing ecosystem processes. Among the functional diversity indices, Functional Richness was the most common metric, usually coupled with indices that incorporate trait abundances such as Functional Evenness, Functional Divergence, Functional Dispersion, Rao, and Functional Redundancy. Future research should seek to integrate ecological networks and connectivity in such a way as to produce guidance with regard to trait selection, applications to large spatial scales, and comparable frameworks (guilds, index values) across regions. Novel approaches are emerging in this field of science, seeking to improve both the connection to both prevailing ecological networks and biotic and abiotic interactions.

Made available in DSpace on 2019-10-04T12:30:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-11-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Fundacao para a Ciencia e a Tecnologia (FCT, Portugal) FC Aguiar We developed a pilot study on the potential of aquatic plants as indicators of ecological quality in tropical rivers to provide an index of biotic integrity for monitoring, conservation, and restoration purposes. We used floristic, environmental, and anthropogenic disturbance data from a 950 km(2) river basin in the southern littoral area of Sao Paulo State, Brazil (Itanhaem River Basin), and proposed a five-step methodological framework for the development of a macrophyte index in tropical river basins. Field surveys were carried out in 137 sites (Spring 2013-2014) of Itanhaem River for the index development and in 27 sites of Itapanhad River (Spring 2015) for its validation. A total of 44 aquatic plant species were recorded in the study area, and 11 metrics were evaluated as potential core metrics of the index. Principal Component Analysis distinguished two river types mostly related to geomorphological characteristics - the Upper river type in the mountainous region (average slope 23.7 degrees) and the Middle-low river type (average slope 9.2 degrees) in the floodplain. The Upper river catchment was characterized by extensive areas occupied by banana plantations, low water conductivity, sandy substrates, and homogeneous aquatic vegetation, whereas the Middle-low river catchment had more urban settlements and displayed high nitrogen and phosphorus contents in water and sediments. The index (MIBI-ITA) is preliminary and was based on species richness and life forms (e.g. submerged hydrophytes, helophytes). MIBI-ITA could only be developed for the lowlands and displayed a high discriminatory ability for distinguishing disturbance and a good performance with external data. Bioassessment in tropical rivers require further investigation on biogeography and long-term responses of macrophyte populations to stressors, as well as knowledge-base on river typology and functional traits of macrophytes, other than morpho-anatomic traits and diversity measures. Univ Estadual Paulista, Programa Posgrad Aquicultura, BR-14884900 Jaboticabal, SP, Brazil Univ Lisbon, Inst Super Agron, Ctr Estudos Florestais, P-1349017 Lisbon, Portugal Univ Estadual Paulista, Dept Ecol, BR-13506900 Rio Claro, SP, Brazil Univ Estadual Paulista, Programa Posgrad Aquicultura, BR-14884900 Jaboticabal, SP, Brazil Univ Estadual Paulista, Dept Ecol, BR-13506900 Rio Claro, SP, Brazil CAPES: 999.009392/2014-09 FAPESP: 2012/21517-9 Fundacao para a Ciencia e a Tecnologia (FCT, Portugal): UID/AGR/00239/2013 FC Aguiar: SFRH/BPD/112417/2015

Riverine landscapes provide numerous ecosystem services, of which pollination is essential to increase the yield, quality, and stability of crops and the biodiversity of wild flora. Pollinators’ behaviour and their community dynamics are often affected by the spatial distribution of floral and nesting resources at the landscape scale, and are thus sensitive to land-use land-cover (LULC) changes and management practices. The main objective of this study is to understand how changes in riparian vegetation and LULC at River Minho affect pollination services. For this, an approach based on the temporal analysis of historical cartography (1898) and current satellite imagery (2016) was used. We developed a novel Pollination Suitability Index for Riverine Landscapes (PSIRL) using LULC data as a proxy of habitat suitability for insect pollinators. PSIRL scores were derived from expert judgment of the local habitat conditions, floral diversity and field surveys. The PSIRL values obtained for both periods were compared using pairwise T-tests. We detected an overall reduction of the pollination services in the riverine landscape of River Minho from 1898 to 2016. However, at local level we observed gains and losses of pollination suitability as a result of distinct LULC changes. There was a marked decrease in the PSIRL in the most downstream and upstream riverine sections due to generalized conversion of scrublands, broadleaved-forests and heterogeneous agricultural areas to artificial surfaces and managed forests dominated by maritime pine and eucalyptus. However, in the middle section of the river, the area occupied by scrublands, riparian and broadleaved forests increased, resulting in an increase of the foraging resources for insects, and a consequent increase of the PSIRL. This index can be used to monitor and capture changes in the pollination suitability of complex riverine landscapes and support further land and river management decisions. The historical cartography proved to be a valuable source of information to characterize LULC change and hence to assess the evolutionary trajectory of pollination ecosystem services, at global and local level.

1. Many riparian ecosystems in Mediterranean Europe are affected by land use and flow alteration by dams. We focused on understanding how these stressors and their components affect riparian forest ...

Dams modify geomorphology, water quantity, quality and timing of stream flows affecting ecosystem functioning and aquatic biota. In this study, we addressed the structural and functional macroinvertebrate community alterations in different instream mesohabitats of two Portuguese rivers impaired by dams. We sampled macroinvertebrates in riffles, runs and pools of river sites downstream of the dams (i.e. regulated; n = 24) and in sites without the influence of the dams (i.e. unregulated; n = 7), assessing a total of 64 mesohabitats, following late spring-early summer regular flows. We found a distinct taxonomic structure and trait composition of macroinvertebrate assemblages between regulated and unregulated flow sites, and also between mesohabitats in which the differences were more evident. When analysing each mesohabitat individually, the effect of flow regulation was detected only in run-type mesohabitats for both taxonomic and trait composition, leading us to infer that a selective macroinvertebrate assessment on run mesohabitats would be a valuable contribution to detect regulated flow effects on ecosystems impaired by dams. Additionally, there is evidence that respiration and locomotion traits could be effective tools to identify damming flow alterations. This study supports that the quality assessments of rivers impacted by dams could benefit from a sampling approach focused on run mesohabitats and the detection of some key traits, which would improve assessment accuracy.

River hydromorphology has long been subjected to huge anthropogenic pressures with severe negative impacts on related ecosystems’ functioning and water quality. Therefore, improving river hydromorphological conditions represents a priority task in sustainable river management and requires proper assessment tools. It is well known that riparian vegetation plays a crucial role in sustaining river hydromorphological conditions. However, it has been nearly neglected in most hydromorphological assessment protocols, including the European Water Framework Directive (WFD). This paper reviews and synthesizes the relevance of riparian vegetation for river hydromorphology, focusing on its contribution to streamflow and sediment regime conditions. We also examine how riparian vegetation is considered in the WFD and how it is included in national hydromorphological protocols currently in use. Our findings point to a temporal mismatch between the date when the WFD came into force and the emergence of scientific and technologic advances in riparian vegetation dynamism and bio-geomorphic modeling. To overcome this misalignment, we present promising approaches for the characterization and assessment of riparian vegetation, which include the identification of vegetation units and indicators at multiple scales to support management and restoration measures. We discuss the complexity of riparian vegetation assessment, particularly with respect to the establishment of river-type-based reference conditions and the monitoring and management targets, and propose some attributes that can serve as novel indicators of the naturalness vs. artificiality of riparian vegetation. We argue that the hydromorphological context of the WFD should be revisited and offer guidance to integrate riparian vegetation in river hydromorphological monitoring and assessment., The work leading to this paper was developed within the COST Action (CA16208) – CONVERGES (Knowledge Conversion for Enhancing Management of European Riparian Ecosystems and Services), supported by COST (European Cooperation in Science and Technology; www.cost. eu). Vanesa Martínez-Fernández was funded by a “Juan de la Cierva” research contract (Spanish MINECO grant no. FJC2018-035451-I at National Museum of Natural Sciences, CSIC, Spain. Francisca C.Aguiar is supported by national funds via FCT under the contracts Norma Transitoria - DL57/2016/CP1382/CT0028. The Portuguese Foundation for Science and Technology (FCT) supported Patricia María Rodríguez- González through FCT investigator programme IF/00059/2015 and the Forest Research Centre through grants UID/AGR/00239/2019 and UIDB/00239/2020.

1. River regulation affects riparian systems world-wide and conservation and restoration efforts are essential to retain biodiversity, and the functioning and services of riverine ecosystems. Effec ...

Contemporary large-scale river ecology is grounded on the existence of patterns in the distribution of aquatic communities, structured by prevailing abiotic conditions. Here, we investigated the existence of functional consistent associations of traits (i.e., traits appearing consistently together at different sites and the same river type) between different biological elements of the aquatic community, assuming that species traits confer them advantages for certain environmental conditions but also within the aquatic community. If this is true, these trait associations should be consistently found in water bodies with similar characteristics (river types), defining different types of ecosystem functioning. To test this, 79 least-disturbed sites, belonging to five well-defined Portuguese river types and covering the longitudinal river gradient were used: headwaters of semi-arid streams, mountainous streams and northern-Atlantic climate streams, middle reaches and lowland large rivers. For each river type, we analyzed the strongest associations (via the Bray–Curtis coefficient) between diatoms, benthic invertebrates and macrophytes and traits that could be relevant to their interactions (e.g., invertebrate trophic groups, mobility/fixation ability of diatoms, macrophyte affinity to water) against a priori predictions. The strongest associations of traits changed over the river continuum with an increase in their complexity (number of associations) from headwaters to middle reaches and a decrease in lowland large rivers. These changes were not related to total richness, which was similar for all river types and over the continuum (ca. 100 taxa). In the three types of headwaters, there were also clear differences in associations among aquatic elements. The importance of riparian trees in small streams was not as high as expected while instream macrophytes were more relevant than predicted. This study revealed the existence of predictable functional associations that could serve as a basis for the functional assessment of running waters.

Dams strongly impair the fluvial environment by altering downstream flows. We analysed riverscapes downstream of three dams and hypothesized that different dam types in rivers with diverse history of land-use and land cover (LULC) change have significant riparian cover differences at diverse biogeomorphic units (banks, riverbanks, islands). We performed a temporal comparison using pre-dam (1965) and post-dam (2013) high-resolution airborne imagery. A new approach was devised to correct the spatial offset between historical and contemporary imagery. Riparian vegetation and LULC (200 m-buffer) were mapped in three rivers of Portugal regulated by the dams Touvedo (run-of-river), Vilarinho das Furnas and Fronhas (storage reservoirs). Five landscape metrics, measures of shape complexity, area and edge effect of riparian patches were computed, including the Weighted Class Area, a metric developed to better interpret the landscape variation. Our findings provide support for the hypothesis of highly altered riverscapes in the post-dam period. For all case studies riparian patches are presently larger, but with less complex shapes and smaller edges. In the present study riparian patches encroach into the river channel, occupy more area and are larger at the two reservoir rivers than at the run-of-river setting. Riparian growth trajectory at the latter is mainly outwards from the active channel and non-vegetated areas in riverbanks and banks are significantly larger; likely due to the washing flows. Redundancy analyses indicated that riparian change was driven by both LULC (agricultural land abandonment and unmanaged forests) and hydrological alterations that jointly determine the structure and spatial trajectories of riparian expansion.

Large rivers on the Iberian Peninsula reflect a long-history of human interventions and natural disturbances in the fluvial corridors and on the surrounding valleys. In this study we aim to characterize the river morphology in pre-regulation times and understand the morphological changes of the large river Tagus (Central Portugal), across space and time. For this, we used comparable military thematic maps from three dates (1855, 1940 and 2000) and evaluated the river landforms, including sinuosity, aquatic, geomorphic and riparian aspects, in three geomorphological zones (Upland, Middle, and Lowland) using a Geographic Information System (GIS). We related the landform variations to the hydrological alterations and to Land-use Land-Cover (hereinafter LULC) changes at valley level. Hydrological data were achieved by simulating river flow regime using the Soil and Water Assessment Tool (SWAT) model. LULC data was obtained by on-screen digitizing of the military thematic maps complemented with ancillary bibliographic information. Metrics for channel form, aquatic and riparian features were quantified in 51 sampling units of 2500 m-long river sections for each period to describe the river morphology. Shannon-Wiener Index (H’) was applied as a descriptor of the morphological diversity. Data analysis revealed a narrowing of the main channel, an overall reduction of the sinuosity, a smaller number of instream geomorphic units and abandoned lateral channels on the most recent period. Morphological alterations were driven primarily by the reduction of floods and sediment inputs, caused by streamflow regulation, while the agricultural intensification, the augment of forest plantations and the reduction of the Mediterranean scrublands induced changes in sediment dynamics and altered the riparian connectivity. The Upland zone showed the highest morphological alterations switching from a historical high-energy section to a low-dynamic zone. We also observed a high morphological variability in the Middle course exhibiting multifaceted gradients of change, while the Lowland zone reflected continuous but less pronounced modifications. River management planning should express the insights of how past and present human alterations affect morphological processes in river-floodplain systems, particularly taking into account river zones’ specificities and how they may react or constrain potential restoration processes.

This study aims to estimate the total biomass aboveground and soil carbon stocks in a Mediterranean riparian forest and identify the contribution of the different species and ecosystem compartments to the overall riparian carbon reservoir. We used a combined field and object-based image analysis (OBIA) approach, based on unmanned aerial vehicle (UAV) multispectral imagery, to assess C stock of three dominant riparian species. A linear discriminator was designed, based on a set of spectral variables previously selected in an optimal way, permitting the classification of the species corresponding to every object in the study area. This made it possible to estimate the area occupied by each species and its contribution to the tree aboveground biomass (AGB). Three uncertainty levels were considered, related to the trade-off between the number of unclassified and misclassified objects, leading to an error control associated with the estimated tree AGB. We found that riparian woodlands dominated by Acacia dealbata Link showed the highest average carbon stock per unit area (251 &plusmn, 90 tC ha&minus, 1) followed by Alnus glutinosa (L.) Gaertner (162 &plusmn, 12 tC ha&minus, 1) and by Salix salviifolia Brot. (73 &plusmn, 17 tC ha&minus, 1), which are mainly related to the stem density, vegetation development and successional stage of the different stands. The woody tree compartment showed the highest inputs (79%), followed by the understory vegetation (12%) and lastly by the soil mineral layer (9%). Spectral vegetation indices developed to suppress saturation effects were consistently selected as important variables for species classification. The total tree AGB in the study area varies from 734 to 1053 tC according to the distinct levels of uncertainty. This study provided the foundations for the assessment of the riparian carbon sequestration and the economic value of the carbon stocks provided by similar Mediterranean riparian forests, a highly relevant ecosystem service for the regulation of climate change effects.

1. The first attempts to describe species ecological niches were simple geometric procedures that depict the niche boundaries directly from environmental data. The convex hull was one of such procedures, popular for its simplicity, clear ecological rational and precise definition of the niche. However, it lacked the ability to differentiate areas of the niche with different probabilities of occurrence according to environmental suitability. 2. We incorporate the Tukey depth, a mathematical tool to measure the centrality of a point within a cloud of points on a multidimensional space, in the convex hull approach to (i) propose a new procedure (CH-Tukey) to estimate species’ environmental suitability, and (ii) estimate niche overlap coherently. In addition to a clear ecological rational and simplicity the CHTukey procedure has a number of attractive features: use of presence-only data; independence from background data; invariance to scale; robustness to outliers; and the decomposition of the niche into a finite number of isosuitability levels, permitting the computation of consistent overlap indices. We illustrate the use of CH-Tukey, using occurrence data of the main Quercus species and subspecies from Western Mediterranean Europe, comparing its outputs with BIOCLIM and MAXENT. 3. Results showed distinct niche geometries among the different approaches. BIOCLIM produced rectilinear niches reflecting the assumption that ecological variables are independent in their action on the species. CHTukey, relaxing this assumption, adjusts niche outer boundary and the inner suitability levels to the known occurrences. MAXENT produced unbounded niche geometries, showing abrupt shifts in the species response to the environmental variables. 4. The niche predictions obtained with geometric approaches, BIOCLIM and CH Tukey, are simpler but better aligned with Hutchinson’s niche concept than those obtained with MAXENT, this latter showing ecologically implausible relationships with the environmental variables. CH-Tukey and the related overlap measures provide an adequate tool to explore niche properties and species-environment relationships.

International audience; Aquatic plants fulfil a wide range of ecological roles, and make a substantial contribution to the structure, function and service provision of aquatic ecosystems. Given their well-documented importance in aquatic ecosystems, research into aquatic plants contin- ues to blossom. The 14th International Symposium on Aquatic Plants, held in Edinburgh in September 2015, brought together 120 delegates from 28 countries and six continents. This special issue of Hydrobiologia includes a select number of papers on aspects of aquatic plants, covering a wide range of species, systems and issues. In this paper, we present an overview of current trends and future directions in aquatic plant research in the early twenty first century. Our understanding of aquatic plant biology, the range of scientific issues being addressed and the range of techniques available to researchers have all arguably never been greater; however, substantial challenges exist to the conservation and management of both aquatic plants and the ecosystems in which they are found. The range of countries and continents represented by conference delegates and authors of papers in the special issue illustrates the global relevance of aquatic plant research in the early twenty first century but also the many challenges that this burgeoning scientific discipline must address.

Functional diversity indices are increasingly being used to describe plant community assembly processes and ecosystem functioning. However, their relevance for predicting alterations in ecosystem functioning of riparian plant communities is still largely unknown. We investigated the functional patterns of riparian forests along environmental gradients, using biological and environmental data from 189 well-preserved riverine locations in mainland Portugal. We calculated functional diversity indices (e.g. Richness, Redundancy, Divergence) for four riparian forest types, namely the Alder woodlands, Ash woodlands, Tree-heath shrublands and Mediterranean shrublands, using their plant species composition and 25 plant functional traits. We used multiple linear regression to predict the effect of the environment in the functional structure of riparian forests and ultimately evaluate the resilience of the riparian forests to environmental fluctuations. We found that Mediterranean shrublands have a significantly higher Functional Richness and a lower Functional Redundancy in comparison to the other riparian forest types. Both regional and habitat variables were important for predicting the functional diversity of riparian forests, with varying patterns according to forest types. In particular, we found that the redundancy of Mediterranean shrublands is mostly affected by precipitation, suggesting their potential vulnerability to climate change in the study area. Our results suggest the usefulness of functional diversity measures for conservation and monitoring the ecological functioning of riparian forests.

International audience; Mediterranean watercourses are among the most threatened ecosystems worldwide, being increasingly important to understand environmental drivers of biotic assemblages. Our aim was to provide a comprehensive picture of bryophyte communities in Mediterranean rivers and to determine the environmental factors that influence their distribution. We used floristic data collected for inter-calibration purposes under the European Water Framework Directive and River Habitat Survey, from 474 river reaches in six countries of the European Mediterranean basin. We analysed data through classification, ordination and environmental niche modelling techniques, and classified taxa according to biogeographic and aquatic habitat frameworks developed specifically for bryophytes. These analyses revealed four types of communities influenced by spatio-temporal precipitation patterns, altitude and water chemistry factors, most notably calcium and manganese. Community types are compositionally differentiated, although they share some core taxa and show an overall tendency to have several temperate and exclusively aquatic taxa despite the intermittent nature of water flow in highly seasonal Mediterranean rivers. The modelling approach can be improved at a more local scale when more bryological data and higher-resolution environmental information become available. Given future scenarios of climate change and human alteration of hydrological regimes, broader scales studies are needed to monitor shifts in bryophyte communities.

Europe’s climate change vulnerability pushes for initiatives such as the European Adaptation Strategy and the associated Covenant of Mayors for Climate and Energy. What are the triggers and barriers, for which sectors and for which risks and how is adaptation funded? This paper examines 147 Local Adaptation Strategies in Europe. Key triggers were incentives via research projects, implementation of EU policies and the increasing frequency of extreme climate events. Insufficient resources, capacity, political commitment and uncertainty were the main barriers. Prioritized sectors reflected the main local vulnerabilities - flood protection and water management, built environment and urban planning. Differing patterns of adaptation planning and adaptive capacity were identified among different regions in Europe. Large municipalities generally fund adaptation locally, whereas international and national funding appears to be more important for adaptation in less urban or densely populated territories. The database of LAS described in the present study can be expanded and used to increase the understanding of and promotion of local adaptation action in Europe and beyond.

Dammed rivers have unnatural stream flows, disrupted sediment dynamics, and rearranged geomorphologic settings. Consequently, fluvial biota experiences disturbed functioning in the novel ecosystems. The case study is the large irrigation reservoir Alqueva in Guadiana River, Southern Iberia. The study area was divided into three zones: upstream and downstream of the dam and reservoir. For each zone, species composition and land use and land cover (LULC) were compared before and after the Alqueva Dam implementation. Data consist of aquatic and riparian flora composition obtained from 46 surveys and the area (%) of 12 classes of LULC obtained in 90 riverine sampling units through the analysis of historical and contemporary imagery. There was an overall decrease of several endemic species and on the riparian shrublands and aquatic stands, although differences in the proportion of functional groups were not significant. Nevertheless, compositional diversity shows a significant decline in the upstream zone while landscape diversity shows an accentuated reduction in the reservoir area and downstream of the dam, which is likely related to the loss of the rocky habitats of the &lsquo, old&rsquo, Guadiana River and the homogenization of the riverscape due to the irrigation intensification. The mitigation of these critical changes should be site-specific and should rely on the knowledge of the interactions between surrounding lands, ecological, biogeomorphologic, and hydrological components of the fluvial ecosystems.

The identification of macrophyte reference communities represents a significant challenge in Mediterranean zones, where few aquatic taxa exist compared to other regions of the world. In the highly seasonal rivers of Portugal, we explored the contribution of bryophytes to enhance the compositional and ecological characterization of reference conditions. We performed partitioning, classification, and ordination analyses and obtained eight groups of bryophytic assemblages explained by water availability and quality. Groups A, B, and H assemblages are type-specific of the inland areas of the northern eco-region, reflecting the neutral minerotrophic currents with summer low currents. Groups C and D are type-specific of acidic oligotrophic shifting currents dependent of precipitation events in the mountainous streams of the North Atlantic eco-region. Groups E, F, and G are widespread in continental northern, central, and southern zones in neutral and highly mineralized watercourses with seasonal dryness. We propose bryophytes as a tool in the characterization of the reference conditions for two main reasons: (i) many of the recorded taxa are capable of withstanding the natural seasonal desiccation, and (ii) the type-specific bryophytes have perennial life-strategies and can be assessed at any time of year as a support for other type-specific macrophytes in compositional assessments of reference conditions.

Aquatic and riparian ecosystems are known to be highly vulnerable to invasive alien species (IAS), especially when subjected to human-induced disturbances. In the last three decades, we have witnessed a growing increase in plant invasions in Portugal and Spain (Iberian Peninsula, south-western Europe), with very detrimental economic, social and ecological effects. Some of these species, such as the giant reed (Arundo donax L.) and the water hyacinth (Eichhornia crassipes (Mart.) Solms-Laub.), number among the world's worst weeds. We present an appraisal of this invasive alien river flora and the most problematic aquatic weeds. We review various aspects of invasion ecology, including spatial and temporal patterns of invasion, species invasiveness, species traits of invasive weeds, and relationships between human disturbance in rivers and surrounding areas and invasibility, and contextualize them in overall state-of-the-art terms. We also acknowledge the use of IAS as bioindicators of the ecological quality...

The giant reed ( Arundo donax L.) is amongst the one hundred worst invasive alien species of the world, and it is responsible for biodiversity loss and failure of ecosystem functions in riparian habitats. In this work, field spectroradiometry was used to assess the spectral separability of the giant reed from the adjacent vegetation and from the common reed, a native similar species. The study was conducted at different phenological periods and also for the giant reed stands regenerated after mechanical cutting (giant reed_RAC). A hierarchical procedure using Kruskal–Wallis test followed by Classification and Regression Trees (CART) was used to select the minimum number of optimal bands that discriminate the giant reed from the adjacent vegetation. A new approach was used to identify sets of wavelengths – wavezones – that maximize the spectral separability beyond the minimum number of optimal bands. Jeffries Matusita and Bhattacharya distance were used to evaluate the spectral separability using the minimum optimal bands and in three simulated satellite images, namely Landsat, IKONOS and SPOT. Giant reed was spectrally separable from the adjacent vegetation, both at the vegetative and the senescent period, exception made to the common reed at the vegetative period. The red edge region was repeatedly selected, although the visible region was also important to separate the giant reed from the herbaceous vegetation and the mid infrared region to the discrimination from the woody vegetation. The highest separability was obtained for the giant reed_RAC stands, due to its highly homogeneous, dense and dark-green stands. Results are discussed by relating the phenological, morphological and structural features of the giant reed stands and the adjacent vegetation with their optical traits. Weaknesses and strengths of the giant reed spectral discrimination are highlighted and implications of imagery selection for mapping purposes are argued based on present results.

Questions: What are the species and functional trait composition of riparian forests in near-natural Southwest European rivers? Are functional trait and species assemblages constrained by environment? Location: Near-natural riparian habitats throughout mainland Portugal, Southwest Europe. Methods: We collected data on riparian woody abundances and environmental variables from 175 river locations. Twenty-eight key functional traits were assigned to the surveyed species. Hierarchical clustering and indicator species analysis were used to derive compositional and functional groups of sites. We used Mantel tests to relate species and trait abundances and environmental gradients, and identified sets of relevant variables at diverse spatial scales. Then, four Dispersion indicators were developed to assess the extent to which the groups are constrained by the environment. These measures were tested for significance using iteration procedures. Results: Clustering revealed four compositional groups of sites: Alder woods, Ash woods, Tree–heath shrublands and Semi-arid shrublands; and three functional groups: Mixed riparian forests, Shrublands with fleshy fruits and Stress-tolerant shrublands. These groups were primarily defined by broad-scale gradients of climate, elevation and river hierarchy. The most dispersed groups had broad trait composition (e.g. Mixed riparian forests) and were floristically diverse (Alder woods). In general, the compositional groups were more closely related to environmental gradients than the functional groups. Conclusions: Assemblages with very specific functional traits or with homogeneous species composition were largely constrained to the most extreme environmental conditions in the study area. Future research to assist environmental management should be directed to the role offine-scale environmental determinants of riparian assemblages, especially those related to flow variability and water stress.

According to the Water Framework Directive phytobenthos (diatoms) and macrophytes are part of the same biological element, the aquatic flora, which should be used in monitoring programs for rivers ecological assessment. However, they have been treated separately over time, and different indices are used to reach an Ecological Quality Status. Here we build a predictive model (the AQUAFLORA) based on communities composed of diatoms and macrophytes, with the aim of determining if these two elements of the aquatic flora could be combined in a single model to evaluate the streams ecological quality. For that we used biological and environmental information from 200 reference and 171 disturbed sites distributed through the entire Portuguese mainland territory. After clustering analysis, 5 biological reference groups significantly different (ANOSIM Global R = 0.685; p

The bioassessment and monitoring of the ecological status of rivers using macrophytes has gained new momentum since macrophytes were recognised as biological quality elements for the implementation of the European Water Framework Directive (WFD; EU/2000/60). Our objectives were to test the suitability of two predictive modelling approaches to macrophyte communities as a tool for water quality assessment, and to compare their performance with other more common approaches—the use of macrophytes as indicators of the trophic status of rivers and multimetric indices. We used floristic and environmental data that were collected in the spring of 2004 and 2005 from around 400 sites on rivers across mainland Portugal, western Iberia. We build two predictive models: MACPACS (MACrophyte Prediction And Classification System) and MAC (Macrophyte Assessment and Classification) based on RIVPACS and the BEAST methods, respectively. Whereas MACPACS is derived from taxa occurrence data, MAC uses a quantitative measure of taxa abundance. Both models showed good performance in predicting reference sites to the correct group and low rate of misclassification errors. However, they performed differently. MAC depicts a reliable response to the overall human-mediated degradation of fluvial systems, as does the multimetric index (RVI, Riparian Vegetation Index), but MACPACS presented only a poor correlation with the Global Human Disturbance Index and with the nutrients input. The incorporation of abundance data in vegetation predictive models appears to be particularly important to the detection of high levels of degradation. The values for correlations with physical–chemical pressure variables were lower than expected for MTR (Mean Trophic Rank) due to an insufficient number of scoring species found in Portuguese fluvial systems. Our results suggest that the most effective methods for bioassessment in Mediterranean-type rivers are either the RVI or the MAC predictive model.

1. A comparison was made between a variety of alien and endemic plant species from 272 aquatic and riparian habitats in Portuguese Mediterranean-type streams in reference condition — i.e. near-natural river corridors — and non-reference condition. The objective was to detect differences in relative proportion and cover between these species groups. The differences in endemic and alien flora from siliceous and calcareous river types were also analysed. Environmental and human disturbance factors were related with the richness and cover of both species groups. 2. A total of 568 species were found, of which 44 were alien and 28 were endemic. Alien species were present at 91% of the surveyed locations, and were consistently more widespread at non-reference sites than at reference ones for both river types, with calcareous sites having a higher invasibility. Endemic species occurred at 45% of the sampling sites and displayed a significantly lower richness and cover than their alien counterparts. 3. Alien richness and cover were positively related to direct human disturbance within the river systems, and with floodplain uses such as urban occupation, intensive agriculture, and nutrient inputs. Endemic species also respond to anthropogenic variables, rather than to climatic and geographical ones, with richness and cover increasing as human impacts on fluvial systems and related floodplains decrease. 4. Comprehensive control of alien invasive species and the protection of endemic plant populations will require attempts at monitoring ecological river integrity, and the achievement of ‘good ecological status’ — one of the goals of the European Union's Water Framework Directive. Portuguese riparian areas must be managed in such a way as to protect the relatively few preserved riparian habitats by lowering the direct and indirect pressures in fluvial corridors and thus preventing future alien plant invasions. Copyright © 2006 John Wiley & Sons, Ltd.

Patterns of native and exotic species richness and cover were examined together with the composition of species assemblages along a typical Mediterranean river and across its floodplain. Major goals were to characterize species distribution regarding diverse environmental and habitat features, and to explore floodplain landforms relations using plant assemblages and invasion responses as biological indicators of aquatic–terrestrial connectivity. A floristic survey was undertaken during May and early June 1998 in six sites of a southern Iberian basin. Vegetation data were gathered from three transects in three landforms: inundated and frequently flooded banks (FF), infrequently flooded valley floors (IF), and rarely flooded higher floodplains (RF). We used 2×2 m plots to record each species present and visual estimates of percentage cover of each species. Cover of native and exotic species assemblages were also estimated for each plots, for the transects, and for the landforms. The total number of vascular plant species found was 287 of which only 26 were exotic. Despite the high environmental and geomorphological variability, the hierarchical classification showed that species composition varied across the floodplain, rather than along the river. The IF and RF landforms were the most species-rich, both for native and exotic species group, whereas the cover trends of exotic and native plant species were opposed, with exotics being consistently more abundant in FF, and native cover increasing towards RF landforms. We found positive correlations between native and exotic species richness on the floodplain scale, and on a smaller scale in FF and IF landforms, thus supporting the hypothesis that in aquatic and riparian ecosystems of semi-arid landscapes, species-rich communities are preferentially colonized by exotic species. However, this pattern was not consistently coupled with a high cover of exotic species, and it was not sustained for the dry areas of the RF landforms.

Chronological studies (1951–1995) of the changing land use in three river basins belonging to the Tagus fluvial system (Portugal) were conducted using remote sensing data. The spatial characteristics of riparian woody vegetation and the temporal changes therein were quantified using landscape metrics such as average riparian canopy width, length of stand canopy closure types on river segments and patchiness indicators (e.g., the number of changes between types per survey unit). We also studied the predictive potential of geomorphology and climate features for explaining biological variability. We identify significant spatio-temporal land use changes on the adjacent floodplains, accompanied by remarkable differences in riparian integrity. Neither fragmentation patterns nor the loss or increase of riparian cover were consistent with similar land use changes throughout the rest of the studied basins, particularly in urbanizing landscape patches. The longitudinal patterns of streamside forests along Mediterranean-type rivers – particularly in Iberia – appear to be complex and dependent upon the previous life-history features of land use. Results also suggest that the proximity, type and extension of land use patch interplay influence the degree of changes in riparian integrity, which in overall terms displayed appreciable resistance to alterations and indirect disturbance. The results are broadly discussed with regard to spatial fine-grained scale changes in both land use and riparian integrity.

Aquatic and riparian plant species were examined in order to propose a multimetric plant index to assess the biotic integrity in Iberian rivers. An additional analysis with two other plant indices was performed to evaluate the present approach. A floristic survey was undertaken during May and early June 2000 in southern Iberian rivers. After the identification of two vegetation types, a partial canonical correspondence analysis of the floristic data with anthropogenic variables permited the recognition of the least perturbed sites, using the environmental characteristics as co-variables to account for natural site variability. From the 22 candidate-metrics, 8 were selected for inclusion on the final multimetric index: 3 representing composition measures (number of riparian and aquatic species, and number of annual species), 3 reflecting direct human-disturbances (abundance of Arundo donax, number of exotic, ruderal species), 1 trophic measure (number of nitrophyllous species) and 1 related with the riparian integrity (relative riparian width). Quality outputs were correlated with a global disturbance measure in order to evaluate the index performance and compared with the results of other plant indices. The Iberian multimetric plant index (IMPI) displayed a promising ability to relate riparian vegetation features to the current range of global disturbance. The IMPI will need to be further validated, with an enlarged set of metrics and a wider geographical area with clearly unimpaired reference sites in each vegetation type.

Human activities within fluvial corridors and surrounding landscapes have persistently stressed riparian ecosystems, particularly in Iberian Mediterranean-type streams. The impact of human disturbance relative to natural environmental factors in shaping riparian vegetation is still poorly understood. Both regional variables (such as altitude and precipitation), and site-specific characteristics (such as substrate and riverbank modifications) were analysed as potential determinants of riparian vegetation patterning to determine the relative influences of the diverse land-use types and environmental factors on the composition (including floristic species richness and percentage cover of trees, shrubs and woody climbers) and integrity (width of riparian woods and patterns of longitudinal continuity) of riparian woods in eight river basins of the Tagus fluvial system (Portugal). There was patchy establishment of riparian woods, with generally low average width and low species richness, as well as significant inter-basin differences and upstream-downstream variations in riparian features. Species distribution was clearly determined by environmental factors, such as human disturbance on the riverbanks and geological background, and the environmental variables and the land use in the river valley partially explained the integrity of riparian woody vegetation. The results highlight the predictive capability of reach-level features; it appears that, linked with the geomorphological and climate context, small-scale human disturbances on riparian corridors play a major role in explaining the remaining biological variability.

This study attempts to develop and discuss the applicability of a method for using river plant assemblages as indicators of ecological quality in a southern Iberian basin, located in Portugal. Several relevant aspects contribute to make this purpose scientifically challenging. Two thirds of the basin are located in Spanish territory, a large part of the river system is intermittent, the historical reference data on river plants in the basin are non-existent and the distribution patterns of Iberian river plants are scarcely known. A survey of 40 sites was conducted in late spring 1999, covering all the basin. Vegetation data were treated by hierarchical classification and by canonical correspondence analysis, using both environmental (19) and anthropogenic (9) variables. Three plant ecotypes were identified, having different geological and geographical backgrounds. For the selection of reference sites of each ecotype, the environmental variables significantly explaining within-ecotype species distribution were determined by a forward selection procedure and latterly used as co-variables. A partial canonical correspondence analysis was then performed for each ecotype, using a unique variable for the anthropogenic influence, henceforth, leading to a sequence of less human disturbed sites being opposed to the more disturbed ones along the first canonical axis. A cluster analysis for the group of sites of each ecotype contributed to the final distinction of the reference sites, still presenting some intrinsic natural floral variability. The Bray-Curtis dissimilarity within the group of sites from each ecotype ranged between a natural similarity variation and a maximum dissimilarity (a community within the same ecotype but with a plant composition completely different from the floral reference). This range was partitioned into four classes of floristic quality corresponding to an increasing deviation from the pro-natural floristic state. The use of river plants as indicators of river integrity and the method used are discussed, considering the particular features of the river system studied and its plant assemblages.

The composition of macroinvertebrate assemblages was studied at 31 sites in the Sado basin, a lowland area with intermittent rivers located in southern Portugal. Riparian features of the sites, including bankfull width, composition, cover, shade, and relative amount of tree debris, were also measured, and local and basin abiotic variables were determined. Woody vegetation in the Sado basin was species poor and was dominated by the ash Fraxinus angustifolia, the alder Alnus glutinosa, and the willows Salix alba and S. salvifolia. The study sites included a broad range of cover and riparian longitudinal integrity. Macroinvertebrate assemblages revealed low levels of richness (4-29 taxa, average 17.6) and Shannon's diversity (0.65-2.87 bits, average 1.89), and were dominated by species or groups (especially chironomids) that tolerate organic pollution and habitat disturbance. Assemblages were composed of collector-gatherers (5.4-100%, average 58.1), and to a lesser extent collector-filterers (0-81.3%, averag...

Channelization is often a major cause of human impacts on river systems. It affects both hydrogeomorphic features and habitat characteristics and potentially impacts riverine flora and fauna. Human-disturbed fluvial ecosystems also appear to be particularly vulnerable to exotic plant establishment. Following a 12-year recovery period, the distribution, composition and cover of both exotic and native plant species were studied along a Portuguese lowland river segment, which had been subjected to resectioning, straightening and two-stage bank reinforcement, and were compared with those of a nearby, less impacted segment. The species distribution was also related to environmental data. Species richness and floristic composition in the channelized river segment were found to be similar to those at the more ‘natural’ river sites. Floral differences were primarily consistent with the dominance of cover by certain species. However, there were significant differences in exotic and native species richness and cover between the ‘natural’ corridor and the channelized segment, which was more susceptible to invasion by exotic perennial taxa, such as Eryngium pandanifolium, Paspalum paspalodes, Tradescantia fluminensis and Acacia dealbata. Factorial and canonical correspondence analyses revealed considerable patchiness in the distribution of species assemblages. The latter were associated with small differences in substrate composition and their own relative position across the banks and along the river segments in question. Data was also subjected to an unweighted pair-group arithmetic average clustering, and the Indicator Value methodology was applied to selected cluster noda in order to obtain significant indicator species. Copyright © 2001 John Wiley & Sons, Ltd.

This paper exposes a new methodological approach to solve the problem of intercalibrating river quality national methods when a common metric is lacking and most of the countries share the same Water Framework Directive (WFD) assessment method. We provide recommendations for similar works in future concerning the assessment of ecological accuracy and highlight the importance of a good common ground to make feasible the scientific work beyond the intercalibration.The approach herein presented was applied to highly seasonal rivers of the Mediterranean Geographical Intercalibration Group for the Biological Quality Element Macrophytes. The Mediterranean Group of river macrophytes involved seven countries and two assessment methods with similar acquisition data and assessment concept: the Macrophyte Biological Index for Rivers (IBMR) for Cyprus, France, Greece, Italy, Portugal and Spain, and the River Macrophyte Index (RMI) for Slovenia. Database included 318 sites of which 78 were considered as benchmarks. The boundary harmonization was performed for common WFD-assessment methods (all countries except Slovenia) using the median of the Good/Moderate and High/Good boundaries of all countries. Then, whenever possible, the Slovenian method, RMI was computed for the entire database. The IBMR was also computed for the Slovenian sites and was regressed against RMI in order to check the relatedness of methods (R2=0.45; p

The main goal of this study was to create a database that ultimately serves further studies on riparian vegetation and flow response guilds in the boreal region and on transferability of results across different regions. To achieve this aim, we compiled traits for all woody riparian species in northern Sweden which, directly or indirectly, underlie their responses to hydrological and hydraulic conditions, between October 2012 and April 2015. Consulted sources of information were diverse, ranging from scientific to informative and whose accuracy might or might not be verified. They were focused on particular or several traits and species from concrete areas to a worldwide perspective. Sources were characterized by different degrees of accessibility and showed a wide variety of descriptions, categorical and ordinal classifications, and numerical information for each trait. Our effort was to synthesize information for each trait from all sources into the common frame of our own database, following own defined criteria so that comparisons between species are congruent. Therefore, this data set is unique in that it comprehensively combines and homogenizes morphological, phenological, reproductive, and ecological data for 59 woody, riparian, boreal species and from 118 sources of information, that would otherwise be scattered and hardly available.

The present report describes a three-step approach that was used to characterize and define thresholds for the Least Disturbed Condition in Mediterranean streams of four different types, regarding organic pollution and nutrients, hydrological and morphological alterations, and land use. For this purpose, a common database composed of national reference sites (929 records) from seven countries, sampled for invertebrates, diatoms and macrophytes was used. The analyses of reference sites showed that small (catchment100 km(2)) siliceous and non-siliceous streams were mainly affected by channelization, bank alteration and hydropeaking. Medium-sized siliceous rivers were the most affected by stressors: 25-43% of the samples showed at least slight alterations regarding channelization, connectivity, upstream dam influence, hydropeaking and degradation of riparian vegetation. Temporary streams were the least affected by hydromorphological changes, but they were nevertheless affected by alterations in riparian vegetation. There were no major differences between all permanent stream types regarding water quality, but temporary streams showed lower values for oxygenation (DO) and wider ranges for other variables, such as nitrates. A lower threshold value for DO (60%) was determined for this stream type and can be attributed to the streams' natural characteristics. For all other river types, common limits were found for the remaining variables (ammonium, nitrate, phosphate, total P, % of artificial areas, % of intensive and extensive agriculture, % of semi-natural areas in the catchment). These values were then used to select the list of reference sites. The biological communities were characterized, revealing the existence of nine groups of Mediterranean invertebrate communities, six for diatoms and five for macrophytes: each group was characterized by specific indicator taxa that highlighted the differences between groups.

A metric was developed for assessing anthropogenic impacts on aquatic macrophyte ecology by scoring macrophyte species along the main gradient of community change. A measure of ecological quality was then calculated by Weighted Averaging (WA) of these species scores at a monitoring site, and comparison to a reference condition score. This metric was used to illustrate the difficulties of developing aquatic macrophyte indices based on indicator species in Mediterranean rivers. The response of the metric to a nutrient gradient was examined within two different river typologies: the national typology designed for the Water Framework Directive and a typology that segregates the environmental variables to produce maximum species similarity within a river type. Both typologies showed the strong north–south climatic divide in Portugal, with southern rivers having long periods without rainfall and often without flowing water in the summer. Overall, the metric responded well to nutrient impacts however it performed poorly in some southern lowland river types. This was thought to be due to low numbers of aquatic macrophytes in temporary rivers. Non-aquatic species that establish in the river channel of temporary rivers may have to be included in indices to improve performance. Also, simple Weighted Averaging (WA) metrics may be insensitive to abundance changes and loss of rarer indicators in lowland Mediterranean rivers. More sophisticated methods of using WA are suggested, as well as further research into developing assessment methods specific to the character of Mediterranean rivers.

Riparian areas are among the most threatened habitats in the world, due to human activities and land use in adjacent areas. In this study we sought to identify landscape metrics for describing the spatial patterns of riparian vegetation affected by land use. We also hypothesize that land use in the immediate vicinity of the riparian area (considered as a 30-m buffer) can have a greater effect on the structure of riparian vegetation than that in an enlarged buffer (i.e. 200 m). The study was conducted in the highly humanized River Tagus watershed (Central Portugal; Western Iberia), along over 80km of river stretches. Riparian vegetation and land use data were obtained from high-resolution digital images (RGB-NIR 0.5m×0.5 m, spring 2005). Patch analyst was used to calculate landscape metrics related to the spatial configuration, isolation, inter-connectivity, and distribution of patches of three riparian cover classes (tree, shrub, and herbaceous). We quantified and accounted for the global and local spatial autocorrelation of data. Data treatment included redundancy analysis and geostatistic methods. Results showed that only a combined interpretation of various landscape metrics can consistently describe the spatial patterns of riparian vegetation. Riparian vegetation near agricultural areas (irrigation crops, rice fields, orchards, and vineyards), presented a low number of much smaller riparian tree patches with less complex shapes, and a low interspersion of the patch distribution. We found that proximal land use affects the structure of riparian vegetation more than distal land use – an important consideration for the establishment of streamside protection buffers info:eu-repo/semantics/publishedVersion