Riparian Forest Quality Research Articles

Estimation of the ecological integrity of the Guadiana River using Partial Least Squares Path Modelling and simulation scenarios

Ecological integrity is fundamental to human life and ecosystems, so its assessment and management are crucial. This concept assesses ecosystem health by examining physico-chemical and biological characteristics, riparian vegetation and macroinvertebrate communities. In recent decades, water resources have undergone significant changes due to various factors that have contributed to the physical, chemical and biological pollution of water. To address this problem, a specific model has been developed using the Partial Least Squares Path Modelling methodology to analyse and quantify the main factors affecting the ecological integrity of the Spanish part of the Guadiana River (Spain). The variables analysed at the different sampling points in the catchment include forest cover, anthropogenic pressure, water quality and biological integrity. Water quality and biological integrity, in turn, constitute the concept of ecological integrity. The model predicts 60.3 % of the physico-chemical water quality and 56.6 % of the biological integrity, showing that ¨Forest cover¨ negatively impacts water quality (W = −0.476) by reducing pollution, while ¨Anthropogenic Pressure¨ positively impacts it (W = 0.680) by increasing pollution. Based on the modelling, three future scenarios were designed, from the lowest to the highest pressure considering changes in riparian forest quality based on QBR and changes in the number of reservoirs: a favourable scenario with high riparian forest quality and no reservoirs; an intermediate scenario with good riparian forest quality and no change in the number of reservoirs; and an unfavourable scenario, characterised by very poor riparian forest quality and an increase in the number of reservoirs. In this context, the importance of the conservation and enhancement of riparian vegetation as a nature-based solution is highlighted, as well as the pressure generated by industrial activity and agricultural practices on the ecological integrity of the study area. The favourable scenario, with very good quality riparian vegetation, improves water quality by up to 85 %, positively impacting the ecological integrity of the river. In contrast, the unfavourable scenario, with extremely degraded riparian forest, would decrease water quality by up to 62 %, negatively affecting ecological integrity. Modelling and future scenarios is an essential tool in the decision-making process to improve environmental governance and water security. In addition, the PLS-PM methodology allows the identification and quantification of relationships between complex variables, providing a solid basis for the design of effective environmental management strategies.

Evaluating the riparian forest quality index (QBR) in the Luchena River by integrating remote sensing, machine learning and GIS techniques

The Water Framework Directive (WFD 2000/60/EU) is a mandatory standard that aims to improve and protect water quality in Europe. It covers, among other issues, the need to establish particular reference conditions for assessing river ecosystems and defines the ecological status of water bodies and conserve the hydromorphological characteristics of rivers. The quality of riparian vegetation is an important component of stream status and contributes directly to a river's ecological stability. QBR index (“Qualitat del Bosc de Ribera”) is one of the most widely used methods of evaluating riparian quality. This paper presents a new methodological version of the QBR index (QBR-GIS) to assess the ecological status of riparian forests. For this purpose, we have considered the four major conceptual blocks of the QBR index (total vegetation cover, cover structure, cover quality and channel alteration) using geographically referenced information, remote sensing and machine learning techniques. To obtain the cover quality indicator, several vegetation indices were calculated and a sensitivity analysis was performed. The QBR-GIS was validated from the results obtained from the QBR index. QBR-GIS provides greater reliability and objectivity in the results. Furthermore, it reduces the time spent on field visits and increases accuracy in obtaining the status of riparian quality. Furthermore, it is a useful tool for landscape planning and management, improved ability to apply the QBR Index to larger areas of the river catchment, resulting in more information on riparian quality.

Functional diversity of benthic macroinvertebrates regarding hydrological and land use disturbances in a heavily impaired lowland river

This paper proposes the exploration functional diversity of benthic macroinvertebrates to evaluate their response to hydrological and land use stressors in a semi-arid lowland river. We aim to assess dominant functional traits and their sensitivity to environmental drivers, and how functional diversity respond to anthropogenic ecosystem impacts. Environment was evaluated through physical-chemical characterization of water, substrate and hydrological indices. For riparian condition assessment, we applied the QBR index for riparian forest quality and hemeroby index for level of anthropogenic intervention on the landscape. Links between environmental variables (R), taxa distribution (L) and trait composition (Q) were examined with RLQ and combined with fourth-corner analysis. The principal disturbance gradient was related to discharge regulation overlapping with land use represented by hemeroby index. There was also a gradient related to the hydrological regime which alternates seasonal floods with low flow periods. Traits related to reproductive and dispersal strategies were the most influenced by disturbance gradients, both natural and anthropogenic. Functional diversity decrease in sites subject to water abstraction and with higher hemeroby levels. Our findings have been promising in order to the application of functional diversity for biomonitoring in the Dulce River. Hemeroby enables the identification of trending changes between land uses, as well as to identify threat contexts. Furthermore, hemeroby could be useful in diagnostic stages to propose biomonitoring sites, by setting areas with different anthropogenic intervention on the ecosystem.

Exploring land snails’ response to habitat characteristics and their potential as bioindicators of riparian forest quality

Riparian ecosystems are crucial for landscape-level biodiversity, especially in highly anthropic and agricultural areas. Although the low mobility of snails reduces their dispersal capacity and makes them vulnerable to habitat degradation, they are less commonly used as indicators. We evaluated the potential of land snails as bioindicators of riparian forest quality in central European riparian forests by surveying snail communities in relation to habitat characteristics that characterize its quality. Habitat characteristics were found to affect both snail abundance and species richness. The abundance of snail species increased with the forest continuity, forest width and abundance of leaf litter and decreased with the cover of ruderal plant species and presence of household waste deposits. Snail diversity was positively influenced by habitat continuity, forest width, and abundance of dead wood. The community composition was also sensitive to habitat characteristics, most species having their optimum in habitats with high amounts of decaying dead wood and litter. Many species responded positively to habitat continuity, demonstrating that fragmentation is the main factor affecting abundance of land snail communities. Both total abundance of land snail communities and species richness were good predictors of habitat quality, snail abundance being more powerful than diversity. Aegopinella epipedostoma, Perforatella bidentata, and Helix pomatia were best at discriminating among high and poor quality forest habitats among individual species. Our study showed that among the parameters describing habitat quality, spatial and temporal continuity of riparian forest are the main factors affecting snail communities. Habitat fragmentation and the absence of suitable microhabitats for snail species preferring decaying wood lead to lower abundance and diversity of land snail communities confirming the potential of land snails as bioindicators of riparian forest quality.

Riparian land use and stream habitat regulate water quality

Riparian land use is a key driver of stream ecosystem processes but its effects on water quality are still a matter of debate when proposing measures to improve freshwater quality. The aim of this study was to examine the influence of riparian land use on stream habitat and water chemistry, and to assess in what extent stream habitat also affects water quality. To that end, we selected eight reaches in the Ave River basin (northwestern Portugal) and compared longitudinal variations in water chemistry and stream habitat between reaches with different land use (urban, agricultural and natural), and between reaches with natural riparian areas and different habitats. Stream habitat was assessed using the Fluvial Functional Index, the HABSCORE, and the Riparian Forest Quality Index. Longitudinal variations in water chemistry were determined measuring differences in concentrations of ammonium, nitrate, phosphate and oxygen, and conductivity, pH and temperature between the downstream and the upstream ends of each reach. Nitrate concentration tended to decrease along reaches with more natural riparian areas and to increase along reaches with more urban and agricultural land uses. Longitudinal variations in water chemistry also differed between reaches with natural riparian areas, suggesting that water quality also depends on stream habitat. Moreover, longitudinal variation in water chemistry was proven a simple, useful and low-cost approach to assess the influence of land cover and stream habitat on water quality. Overall results demonstrated that both riparian land use and stream habitat influence water quality and that riparian forests are essential to reduce nutrient export to downstream ecosystems.

The role of riparian vegetation in the evaluation of ecosystem health: The case of semiarid conditions in Northern Mexico

AbstractThe Pesquería River (north‐eastern Mexico) has long been subjected to considerable anthropogenic pressures. For this reason, it has been identified by the Mexican National Commission for the Knowledge and Usage of Biodiversity as a priority resource to be evaluated and restored. In order to establish the means required for the restoration of the river, the condition of its riparian ecosystem must be evaluated. To evaluate the quality of the riparian forest, we adapted the Qualitat del Bosc de Ribera index methodology for Mediterranean rivers for the semiarid rivers of north‐eastern Mexico (QBR‐RNMX). The QBR‐RNMX index included modifications to the four sections that comprise the original index, and their values range between 0 and 100. Using the five levels of riparian quality defined in the index, in the area surrounding the Pesquería River, we found poor or very poor conditions at 66% of the sampling sites, average‐good conditions at 27% of the sites, and only one sampling site with excellent conditions. These results show that the riparian forest has been impacted significantly by urbanization, agriculture, and the presence of many invasive species. We recommend the application of the QBR‐RNMX annually in order to evaluate the riparian forest's quality and to assess its ecological status. This may be used for the establishment of restoration plans in high‐impact zones and contingency plans to eliminate invasive species along the Pesquería River.

Riparian reserves help protect forest bird communities in oil palm dominated landscapes

Abstract Conversion of forest to oil palm agriculture is a significant and ongoing threat to tropical biodiversity. Despite this, little is known about the value of riparian reserves in oil palm and how these conservation set‐asides might best be managed to maintain biodiversity. We characterized bird communities of 28 sites in an oil palm‐forest mosaic in Sabah, Malaysia using 6,104 encounters from 840 point counts. Sites included oil palm riparian reserves of various vegetation quality and reserve widths, which were compared to oil palm streams without a riparian reserve as well as riparian and nonriparian control areas in continuous logged forest. Riparian reserves, oil palm waterways, and control sites in riparian and nonriparian forest supported distinct avifaunal communities. Riparian reserve width, forest quality, and amount of forest cover were the strongest predictors of bird species richness. For forest‐dependent species, each of these predictors had a stronger effect size when compared with all species. On average, reserves held 31% of all species and 30% of forest specialists, whereas riparian forest controls averaged 32% of all species, but 38% of forest species. Riparian reserves with >40 m of natural vegetation on each bank supported similar bird diversity to riparian forest control habitats found in continuous forest. However, to support equivalent numbers of forest‐dependent species and species of conservation concern, reserves would need to be at least 100‐m wide on each bank. The largest numbers of species were found in riparian reserves with above‐ground carbon densities exceeding 75 tC/ha, highlighting the importance of forest quality, as well as width, in supporting riparian bird communities. Synthesis and applications. If designed and protected appropriately, riparian reserves in oil palm estates support diverse bird communities, including many species of conservation concern. This can be achieved by designating large reserves (80–200 m total width). But, to maximize species numbers, forest disturbance should also be minimized prior to conversion as well as during plantation operations.

A spatially explicit patch model of habitat quality, integrating spatio-structural indicators

Habitat quality – referring to the structure of a habitat – is crucial for the habitat functions and biodiversity-related ecosystem services. Its effective assessment and monitoring is important to meet not only scientific interest, but also practical conservation regulations. We herein present the approach of using a composite indicator of riparian forest quality, both quantitatively (habitat quality index HQI [0|1]) and categorically (quality types QT1…4), integrating a set of spatio-structural indicators derived from earth observation data. We apply the geon concept to aggregate multiple sets of statistically profound and conceptually meaningful indicators to the well-established patch concept. The main difference is that instead of using a priori units (e.g. existing patch delineations), new patches (geons) are derived that directly represent the phenomenon of habitat quality. Patch boundaries correspond to the gradients imposed by the multivariate behavior of the underlying indicators. The approach provides a truly spatially explicit assessment, while at the same time retaining the potential for decomposability on the level of individual indicators. The example of a riparian forest is chosen, as riparian zones are complex ecosystems with a high biodiversity that are highly threatened. In our case, riparian forest habitat quality was assessed using four indicators: (I) tree species composition, (II) horizontal forest structure, (III) vertical forest structure, and (IV) water regime. The distribution of habitat quality (HQI) highlights hot- and cold-spots, where conservation measures may be needed. Cluster analysis reveals four types of patches that are characterized by a specific behavior of the aggregated indicators (QT1=fair composition, QT2=(old growth) forest plantations, QT3=characteristic tree species, QT4=forest gaps). This categorization enables the prevailing or lacking aspects of quality to be determined based on the decomposability of the index. In addition, the resulting patches were evaluated using landscape metrics. The findings achieved on a statistically significant level show that patches with high HQI scores are better connected and form large patches with a characteristic tree species composition. In contrast, areas with low HQI values are characterized by a non-favorable tree species composition and the existence of clear-cut areas or access roads. A comparison with an assessment using a traditional composite indicator approach reveals the sensitivity of the different sets of indicators and assessment methods. The presented habitat quality index can be considered as suitable for the assessment and monitoring of riparian forest quality, supporting spatially explicit conservation measures and the evaluation of applied measures.

The effects of catchment and riparian forest quality on stream environmental conditions across a tropical rainforest and oil palm landscape in Malaysian Borneo.

Freshwaters provide valuable habitat and important ecosystem services but are threatened worldwide by habitat loss and degradation. In Southeast Asia, rainforest streams are particularly threatened by logging and conversion to oil palm, but we lack information on the impacts of this on freshwater environmental conditions, and the relative importance of catchment versus riparian‐scale disturbance. We studied 16 streams in Sabah, Borneo, including old‐growth forest, logged forest, and oil palm sites. We assessed forest quality in riparian zones and across the whole catchment and compared it with stream environmental conditions including water quality, structural complexity, and organic inputs. We found that streams with the highest riparian forest quality were nearly 4 °C cooler, over 20 cm deeper, had over 40% less sand, greater canopy cover, more stored leaf litter, and wider channels than oil palm streams with the lowest riparian forest quality. Other variables were significantly related to catchment‐scale forest quality, with streams in the highest quality forest catchments having 40% more bedrock and 20 times more dead wood, along with higher phosphorus, and lower nitrate‐N levels compared to streams with the lowest catchment‐scale forest quality. Although riparian buffer strips went some way to protecting waterways, they did not maintain fully forest‐like stream conditions. In addition, logged forest streams still showed signs of disturbance 10–15 years after selective logging. Our results suggest that maintenance and restoration of buffer strips can help to protect healthy freshwater ecosystems but logging practices and catchment‐scale forest management also need to be considered.

Evaluating the use of Myotis daubentonii as an ecological indicator in Mediterranean riparian habitats

In recent years, interest and concern regarding biodiversity conservation have grown remarkably not only among conservationists but also amongst a wider public beyond scientific institutions. The monitoring of fauna and flora over long periods of time has been satisfactorily proven to be a viable tool for quantifying how environmental changes affect natural communities. Some bat species are regarded as good bioindicators, mainly due to their longevity and high sensitivity to environmental changes. Myotis daubentonii is one of the species most closely associated with riparian habitats in the north-east Iberian Peninsula, and is used as an ecological indicator in specific monitoring programs such as the Waterway Survey (United Kingdom) and the QuiroRius (Spain). Nonetheless, there is still great controversy as to whether M. daubentonii is a good biological indicator or not. While some authors accept it as a bioindicator, others point to the studies carried out in the U.K., Poland, Switzerland and Germany that show a remarkable increase in the numbers of this bat when pollution increases in canalized rivers, which suggest that it is in fact a generalist species.Due to the lack of information regarding habitat-quality requirements in Daubenton’s bats in the Mediterranean region and the species’ potential as a bioindicator in riparian habitats, we aimed to 1) examine how QuiroRius data match other well-established biological indicators (IBMWP for invertebrates and QBR for riparian forests); 2) analyse how environmental variables at both local and landscape scales affect the presence of M. daubentonii; and 3) describe how environmental traits influence the relative abundance of M. daubentonii.A total of 104 streams below 1000m a.s.l. were simultaneously sampled using bat, macroinvertebrate and vegetation bioindicators. Despite having similar conservation aims, these three bioindicators did not provide consistent images of overall ecosystem quality and thus a multidisciplinary approach is necessary for a full analysis of the health of these riparian ecosystems. M. daubentonii were found more frequently in wide rivers with well-structured native riparian forests; on the other hand, landscape composition at broader scales and altitude had no influence on bat presence/abundance.Thus, we suggest that QuiroRius could be used as a complementary bioindicator for analysing riparian forest quality but cannot be used alone as a tool for evaluating correctly overall riparian ecosystem health. Both relative abundance and/or presence/absence could be used as bioindicator surrogates given that the effect of microhabitat environmental predictors had similar impact on both these measures.

Visual ecology: exploring the relationships between ecological quality and aesthetic preference

High ecological quality and an attractive environment are usually two primary goals of landscape design. Understanding the relationships between ecological quality and visual aesthetic preference is needed to reach the two goals simultaneously. However, previous work has not provided definite answers regards these relationships. The current study took place in the riparian zone of Xuzhou, China, to check ecological quality using the qualitat del bosc de ribera (or riparian forest quality) index, and visual aesthetic preference using pictures as surrogates, which were assessed by undergraduate students. Regression analysis revealed a U-shaped distribution of ecological quality in relation to visual aesthetic preference, which indicated that, with higher ecological quality, the visual aesthetic preference could be higher or lower, and a lower ecological quality implied a medium visual aesthetic preference. In addition, enhancing the cover quality (introducing more native plants and reducing man-made elements) of riparian vegetation was an efficient way to align the ecological goal with a visually pleasing landscape.

Exploring the Capacity of Water Framework Directive Indices to Assess Ecosystem Services in Fluvial and Riparian Systems: Towards a Second Implementation Phase.

We explored the capacity of the biological and hydromorphological indices used in the Water Framework Directive (WFD) to assess ecosystem services by evaluating the ecological status of Spanish River Basins. This analysis relies on an exhaustive bibliography review which showed scientific evidence of the interlinkages between some ecosystem services and different hydromorphological and biological elements which have been used as indices in the WFD. Our findings indicate that, of a total of 38 ecosystem services analyzed, biological and hydromorphological indices can fully evaluate four ecosystem services. In addition, 18 ecosystem services can be partly evaluated by some of the analyzed indices, while 11 are not related with the indices. While Riparian Forest Quality was the index that was able to assess the largest number of ecosystem services (N=12), the two indices of macrophytes offered very poor guarantees. Finally, biological indices related to diatoms and aquatic invertebrates and the Fluvial Habitat Index can be related with 7, 6, and 6 ecosystem services, respectively. Because the WFD indices currently used in Spain are not able to assess most of the ecosystem services analyzed, we suggest that there is potential to develop the second phase of the WFD implementation taking this approach into consideration. The incorporation of the ecosystem services approach into the WFD could provide the framework for assess the impacts of human activities on the quality of fluvial ecosystems and could give insights for water and watershed management in order to guarantee the delivery of multiple ecosystem services.

An assessment of river habitat quality as an indicator of conservation status. A case study in the Northwest of Spain

There are several methodologies for the characterization and evaluation of river habitats. The scientific community has made a great effort in designing the best indexes for this purpose, and they have also been tested in different countries and rivers. Nevertheless, there has not been a transfer of that knowledge to land managers of these spaces or, at least, to those who design improvement and restoration measures. The aim of our research was the assessment of the Riparian Forest Quality Index (QBR), the “Riparian Quality Index” (RQI) and the “Fluvial Habitat Index” (IHF) as indicators of the ecological status of fluvial habitats and their application in restoration projects. The main results of this study were that the IHF index could be used as a support resource and as a monitoring tool to assess the habitat heterogeneity before and after any action is taken. However, when we evaluated the QBR and RQI indexes, the best results were with the first one. The total QBR suggests the urgency level of restoration in the section that is evaluated, and each of its sub-indexes identifies which element of the river is affected. Therefore, it will be a useful tool in decision making for the conservation of these characteristic spaces, especially for engineers who, as a result of their experience in biological and ecological processes, are involved in the design and building of ecosystems, particularly in rivers and on their banks.

A composite indicator for assessing habitat quality of riparian forests derived from Earth observation data

Riparian forests are precious, complex habitats fostering high biodiversity where effective monitoring of habitat quality is particularly important. We present a composite indicator, referred to as Riparian Forest composite Indicator: focus on Structure (RFI_S), for the assessment of habitat quality and identification of ‘hot-spot’ areas where conservation actions need to be taken. The RFI_S is composed of seven indicators derived from very high resolution (VHR) satellite imagery and LiDAR data, calculated on patch level. These indicators assess four important attributes of riparian forest quality: (1) tree species composition, (2) vertical forest structure, (3) horizontal forest structure and (4) water regime. For the aggregation of the RFI_S, two different weighting schemes, expert-based and statistical weighting, are applied. Forest patches with high cumulative RFI_S values represent patches of good habitat quality. These patches are primarily found along water bodies, reflecting the importance of water bodies for the structural complexity, an optimum water regime and tree species composition. For forest patches of low habitat quality the RFI_S helps to design suitable measures to improve habitat quality status through its decomposability into the underlying indicators. A sensitivity analysis to test the robustness of the RFI_S shows that the indicator variance in terrain roughness has the strongest influence on the composite indicator. Finally, a comparison with an existing expert-based map on conservation status reveals the potential of a complementary quantitative assessment of habitat quality in the study site. We hence conclude that the RFI_S has a high capability to support sustainable forest management complementing regularly gathered in situ data.

Influence of a Small Hydroelectric Power Station on the River Ecosystem.

To assess the effects of the Small Hydroelectric Power Station (SHP) on the fluvial ecosystem, some environmental values are required to measure. This work provides a characterization of the water quality status in a river stretch around a SHP plant on river Mandeo, (NW Spain), for three years after its construction. The ecological and chemical status of the water and the ecological quality of the riparian habitat was analyzed and comparing with the water quality requirements. The results showed that there were not significant differences between sampling points (before and after of the plant), as well as a stabilization of the parameters within two years after the construction of the Station, achieving conditions ecologically compatible. We concluded that the construction of the SHP plant caused an adverse effect in the ecosystem, which was subsequently improved. Highly positive results from the point of view of their contribution as a source of renewable energy. Keywords: Biological index, physicochemical, SHP plant, riparian forest quality index

Characterization of riparian forest quality of the Umia River for a proposed restoration

Riparian forests have an important greening filter effect, retaining particles and nutrients from runoff or subsurface waters. To provide this function, among many others, the conservation and restoration of riparian vegetation is crucial. In this paper, the evaluation of the quality and condition of the riparian forest was carried out through “Riparian Forest Quality” index on a stretch of the Umia River. A total of 55 sampling stations were evaluated. This methodology was applied for decision making in the zoning of the banks. The results indicate that there is clear deterioration of the banks from the reservoir (middle stretch of the river) to the headwaters. Finally, different levels of performance were defined, 64% of the riparian area needs recovery actions, while more than 16% of riparian area needs reinstatement actions and over 18% are conservation stretches. This method provides a useful and practical solution to environmental problems in river ecosystems, especially for planning and landscape management.

Factores ambientales asociados con la preferencia de hábitat de larvas de tricópteros en cuencas con bosque seco tropical (Tolima, Colombia)

River ecosystems, mainly those draining tropical dry forests, are among the most endangered tropical ecosystems and a major conservation priority in South America, as elsewhere. In this study, we assessed the influence of environmental factors (e.g., precipitation) and riparian vegetation on Trichoptera larval assemblages colonizing four substrates (rock, gravel, sand, and litter) in the Venadillo and Opia watersheds (Tolima, Colombia). In each river, five 20m reaches nested into two 100m segments (one at -550 and another at -250masl), were surveyed for benthic invertebrates in the above mentioned substrates. In addition, water samples were collected for physicochemical analyses and the QBR index ("qualitat del bosc de ribera" or riparian forest quality) was applied in both rivers. A total of 6,282 larvae were collected, belonging to 11 families and 22 genera, representing 73.30% and 43.13% of the Trichoptera fauna reported to Colombia, respectively. The most abundant families were Hydropsychidae (49.86%) and Philopotamidae (25.44%) and the least abundant Odontoceridae (0.16%) and Hydrobiosidae (0.06%). The genera Smicridea, Chimarra, Protoptila, Neotrichia, and Leptonema, were common during dry and rainy seasons. The main factors related to changes in composition, richness, and abundance of larval Trichoptera were seasonality and riparian vegetation, which can influence organic matter supply, availability and stability of substrates, and colonization and population dynamics. Trichoptera assemblages showed no significant differences among substrates. However sampling points located at high elevation and in non-urbanized areas offered the largest variety of substrates and richness. Our results indicate that Trichoptera larvae are an important biotic element in freshwater ecosystems and that they are sensitive to environmental changes. Hence, our study suggests that caddisflies may be used as potential organisms for the biomonitoring of tropical dry forest rivers. The implementation of these studies is urgent, considering that degradation of freshwater ecosystems tends to be severe and persistent in dry forest.

Assessment of riparian forest vegetation of rivers supporting the Prespa trout in the Transboundary Prespa Park

The QBR (Riparian Forest Quality) index and the RMP (Riparian Macrophyte Protocol) were used to assess habitat quality and inventory riparian forests in four rivers sustaining the endemic Prespa trout (Salmo peristericus). Total QBR index and total riparian cover (first component of the QBR index) values were found significantly higher in the upper parts of Brajcinska and Kranska rivers, while lower values were recorded in the upper parts of Agios Germanos river and Leva stream. Cover structure, cover quality and channel alteration (the other three components of the QBR index) did not differ significantly between the four watersheds. The greater presence of Fagus sylvatica in the former rivers principally contributes to their increased total riparian area and riverbed cover compared to those of the two latter rivers. In the altitudes below 900 m.a.s.l., where gradients are gentle and human activities intense, vegetation types in all four systems change considerably with the participation of non-native species, while riparian area and riverbed cover are reduced.

Evaluation of the ecological status of an impaired watershed by using a multi-index approach

The objective of this study was to use an integrative approach to assess the ecological status of a small river impacted by multiple sources of disturbance. The River Febros (NW Portugal) is a small and highly impacted non-regulated river; approximately 44% of the watershed area is dedicated to agriculture, but there is also some urbanization. Environmental status was evaluated using a new multi-index approach, combining quality indices for water (Water Quality Index (WQI)), benthic macroinvertebrates (Iberian Biological Monitoring Working Party Index (IBMWP)), and human modification (Riparian Forest Quality Index (QBR)); Ecological Status River Mediterranean Index (ECOSTRIMED); River Habitat Survey (RHS)). Surveys were carried out between October 2002 and 2003, along four stretches of the main course of the river for physicochemical characteristics, as well as water microbiology and macroinvertebrates. Water quality was poor at all sites (WQI averaged 30.4%) and decreased downstream. The RHS (assessment of instream habitats and the river corridor) and the QBR quantification displayed the same trend. Macroinvertebrates diversity was permanently low with only the most tolerant insects taxa present; oligochaetes dominated. The ecological status of River Febros was well represented using the experimental assessment system, where a downstream decrease in condition was noticeable (in spite of a lower water quality upstream). Our results emphasize the importance of assessing several components of disturbed ecosystems in order to ascertain overall quality and the importance of promoting improvement of the riparian gallery as a buffer against multiple agents of disturbance.