Dragos G. Zaharescu

Trace metals and their source in the catchment of the high altitude Lake Respomuso, Central Pyrenees.

Lake Respomuso is a dammed lake of glacial origin at 2200 m altitude in the Central Pyrenees. This study investigated the source of a number of trace elements (As, Cd, Co, Cu, Mn, Ni, Pb and Zn) in its catchment and their possible link to the local geology. Altogether 24 sediment and 29 water samples were collected from all major streams feeding the lake. The sediments were analysed for trace elements, major mineral components, minerals and organic matter whilst water samples were analysed for dissolved metal concentrations. The trace element levels in the catchment sediment and water were relatively high compared to other similar altitude sites, with concentrations in the headwaters being generally higher than in the lower basin because of the source being concentrated in these areas. The principal component analysis revealed that the source of sediment-bound trace elements in the Lake Respomuso catchment is geogenic, and originated possibly in the sulphide minerals from slate formations. Except at one site, none of the water samples exceeded the WHO drinking water guideline for arsenic. Arsenic in water was significantly correlated with its concentration in the sediments, possibly due to the oxidation of arsenic bearing minerals. The dissolved concentrations of all other trace elements were generally lower than the WHO drinking water guide values and they were not related to their sediment concentrations. The As, Cd, Ni contents in sediment from several catchment streams exceeded their sediment quality thresholds. This geogenic source may pose risk to the stability of fragile local biodiversity and to the wider environment in the valley bellow particularly if the metals are mobilised, possibly due to environmental change.

On the arsenic source mobilisation and its natural enrichment in the sediments of a high mountain cirque in the Pyrenees.

Recently arsenic contamination and its environmental and human health problems have been raising concerns worldwide. The occurrence of natural high levels of arsenic contamination has generally been reported for low altitude environments. Here we report a study conducted to assess the extent of arsenic mobilisation/transportation from previously identified arsenic source areas in a high altitude cirque of the Pyrenees as well as the potential contribution of As by snow. The concentration of arsenic in sediments of several tributaries was enriched up to about ten folds due to mobilisation of arsenic from the source areas within the catchment. The highest arsenic enrichments were found in an area dominated by quartzite and slate formation in the southern side of the basin, and it generally diminished towards the major lake downstream, possible due to mixing with sediments from non-source areas. At these sites arsenic exceeded the hazard quotient (HQ) limits for the protection of aquatic life. The potential hazard of the As-enriched sediments may be further enhanced outside the catchment as samples collected downstream the cirque have also shown arsenic concentration exceeding HQ unity. The arsenic concentrations in the water collected at a number of sites exceeded its guide value for the protection of aquatic life. The potential As contribution by snow in the area was low and was largely of lithospheric origin. The PCA analysis showed strong association of arsenic in sediments with the sediment mineralogical composition (Fe2O3, TiO2 and Mn). Arsenic in water was positively correlated with its concentration in the sediments and could potentially increase if the environmental/climate conditions change.

Ecosystem Composition Controls the Fate of Rare Earth Elements during Incipient Soil Genesis

The rare earth elements (REE) are increasingly important in a variety of science and economic fields, including (bio)geosciences, paleoecology, astrobiology, and mining. However, REE distribution in early rock-microbe-plant systems has remained elusive. We tested the hypothesis that REE mass-partitioning during incipient weathering of basalt, rhyolite, granite and schist depends on the activity of microbes, vascular plants (Buffalo grass), and arbuscular mycorrhiza. Pore-water element abundances revealed a rapid transition from abiotic to biotic signatures of weathering, the latter associated with smaller aqueous loss and larger plant uptake. Abiotic dissolution was 39% of total denudation in plant-microbes-mycorrhiza treatment. Microbes incremented denudation, particularly in rhyolite, and this resulted in decreased bioavailable solid pools in this rock. Total mobilization (aqueous + uptake) was ten times greater in planted compared to abiotic treatments, REE masses in plant generally exceeding those in water. Larger plants increased bioavailable solid pools, consistent with enhanced soil genesis. Mycorrhiza generally had a positive effect on total mobilization. The main mechanism behind incipient REE weathering was carbonation enhanced by biotic respiration, the denudation patterns being largely dictated by mineralogy. A consistent biotic signature was observed in La:phosphate and mobilization: solid pool ratios, and in the pattern of denudation and uptake.

A Multiscale Framework for Deconstructing the Ecosystem Physical Template of High-Altitude Lakes

An ecosystem is generally sustained by a set of integrated physical elements forming a functional landscape unit—ecotope, which supplies nutrients, microclimate, and exchanges matter and energy with the wider environment. To better predict environmental change effects on ecosystems, particularly in critically sensitive regions such as high altitudes, it is imperative to recognise how their natural landscape heterogeneity works at different scales to shape habitats and sustain biotic communities prior to major changes. We conducted a comprehensive survey of catchment physical, geological and ecological properties of 380 high-altitude lakes and ponds in the axial Pyrenees at a variety of scales, to formulate and test an integrated model encompassing major flows and interactions that drive lake ecosystems. Three composite drivers encompassed most of the variability in lake catchment characteristics. In order of total percentage of variance explained, they were (i) hydrology/hydrodynamics—responsible for type and discharge of inlets/outlets, and for waterbody size; (ii) bedrock geomorphology, summarising geology, slope and fractal order—all dictating vegetation cover of catchment slope and lake shore, and the presence of aquatic vegetation; and (iii) topography, that is, catchment formation type—driving lakes connectivity, and the presence of summer snow deposits. Although driver (i) appeared to be local, (ii) and (iii) showed gradient changes along altitude and latitude. These three drivers differentiated several lake ecotopes based on their landscape similarities. The three-driver model was successfully tested on a riparian vegetation composition dataset, further illustrating the validity and fundamental nature of the concept. The findings inform on the relative contribution of scale-dependent catchment physical elements to lake ecotope and ecosystem formation in high-altitude lakes, which should be considered in any assessment of potentially major deleterious effects due to environmental/climate change.

Phenotypic indicators of developmental instability in an endemic amphibian from an altered landscape (Monegros, NE Spain)

The great sensitivity of amphibians to land disturbance is one of the main causes that contributed to their worldwide decline. One fundamental approach in assessing amphibian ability to reflect habitat degradation is to measure their phenotypic changes in contrasting environments. We examined the extent to which several morphological traits of the endemic anuran Pelophylax perezi responded to agricultural conversion in Monegros, an arid region in NE Spain. Specifically, we determined how body size, body mass, body condition (BC) and fluctuating asymmetry (FA) of different frog classes varied among habitats with different degree of management, i.e. rice fields vs. control ponds (i.e. small reservoirs). Pelophylax perezi juveniles showed a decrease in size and mass in rice fields, revealing that early life stages are generally more susceptible to habitat alteration. Adult body condition, on the other hand, increased significantly in cultivated habitats, which apparently indicates a good fitness in this size class. Nonetheless, skeletal asymmetry of both, juveniles and adults was significantly higher in rice fields. Moreover, during postmetamorphic development FA increased significantly towards adult stage indicating that the development controlling mechanisms were not able to buffer the stress induced by land use change. Among traits, humerus, radio-ulna and metatarsal were highly sensitive in terms of expressing significant FA differences between habitats, contrary to tibio-fibula, whose precise symmetry is essential for animal locomotion. The former bones have therefore the potential to be used as sensitive indicators of stress in amphibians. FA showed no relationship with body condition. This, together with the previous results demonstrates that FA is able to capture habitat stress more reliably than the morphological estimates such as body size, mass and BC. Therefore, FA is a useful morphological tool, highly recommended to monitor stress levels in amphibian populations.

Small lakes in big landscape: Multi-scale drivers of littoral ecosystem in alpine lakes.

In low nutrient alpine lakes, the littoral zone is the most productive part of the ecosystem, and it is a biodiversity hotspot. It is not entirely clear how the scale and physical heterogeneity of surrounding catchment, its ecological composition, and larger landscape gradients work together to sustain littoral communities. A total of 113 alpine lakes from the central Pyrenees were surveyed to evaluate the functional connectivity between littoral zoobenthos and landscape physical and ecological elements at geographical, catchment and local scales, and to ascertain how they affect the formation of littoral communities. At each lake, the zoobenthic composition was assessed together with geolocation, catchment hydrodynamics, geomorphology and topography, riparian vegetation composition, the presence of trout and frogs, water pH and conductivity. Multidimensional fuzzy set models integrating benthic biota and environmental variables revealed that at geographical scale, longitude unexpectedly surpassed altitude and latitude in its effect on littoral ecosystem. This reflects a sharp transition between Atlantic and Mediterranean climates and suggests a potentially high horizontal vulnerability to climate change. Topography (controlling catchment type, snow coverage and lakes connectivity) was the most influential catchment-scale driver, followed by hydrodynamics (waterbody size, type and volume of inflow/outflow). Locally, riparian plant composition significantly related to littoral community structure, richness and diversity. These variables, directly and indirectly, create habitats for aquatic and terrestrial stages of invertebrates, and control nutrient and water cycles. Three benthic associations characterised distinct lakes. Vertebrate predation, water conductivity and pH had no major influence on littoral taxa. This work provides exhaustive information from relatively pristine sites, and unveils a strong connection between littoral ecosystem and catchment heterogeneity at scales beyond the local environment. This underpins the role of alpine lakes as sensors of local and large-scale environmental changes, which can be used in monitoring networks to evaluate further impacts.

Riparian ecosystem in the alpine connectome. Terrestrial-aquatic and terrestrial-terrestrial interactions in high elevation lakes

Alpine regions are under increased attention worldwide do their role in storing freshwater of high quality and their high sensitivity to climate change - comparable only to the poles. Riparian ecosystems in such regions, integrating water and nutrient fluxes from aquatic and terrestrial environments, host a disproportionally rich biodiversity, despite experiencing severe climate and nutrient restrictions. With climate change rapidly encroaching in the alpine biome, it is important to fully understand how the lake and its surrounding landscape elements sustain such rich ecosystems, before their functional connectivity could be seriously severed. A total of 189 glacial origin lakes in the Central Pyrenees were surveyed to test how key elements of lake and terrestrial environments work together at different scales to shape the riparian plant composition. Secondly, we evaluated how these ecotope features drive the formation of riparian communities potentially sensitive to environmental change, and assessed their habitat distribution. At each lake plant taxonomic composition was assessed together with elemental composition of water and sediment and ecosystem-relevant geographical factors. At macroscale vegetation composition responded to pan-climatic gradients altitude and latitude, which captured, in a narrow geographic area the transition between large European climatic zones. Hydrodynamics was the main catchment-scale factor connecting riparian vegetation with large-scale water fluxes, followed by topography and geomorphology. Lake sediment Mg and Pb, and water Mn and Fe contents reflected local connections with nutrient availability, and water saturation of the substrate. Community analysis identified four keystone plant communities of large niche breadths, present in a wide range of habitats, from (i) damp environments, (ii) snow bed-silicate bedrock, (iii) wet heath, and (iv) limestone bedrock. With environmental change advancing in the alpine biome, this study provides critical information on fundamental linkages between riparian ecosystem and surrounding landscape elements, which could prove invaluable in assessing future biomic impacts. Graphical abstract: Riparian ecosystem of Lake Cardal (0.3ha, 2224m a.s.l) in the Pyrenees National Park (France), with a network diagram of connected landscape elements. Photo by Antonio Palanca-Soler.Riparian ecotones are aquatic-terrestrial interfaces integrating climate and nutrient fluxes across landscape physical elements. Despite experiencing severe nutrient and climate restrictions, high elevation lakes host a disproportionally diverse riparian ecosystem. With climate change rapidly encroaching in the alpine biome, it is vital to understand how the functional connectivity between lakes and their surrounding landscapes maintains a natural ecosystem diversity before they experience major deleterious effects. A total of 189 glacial origin lakes in the Central Pyrenees were surveyed to test how key elements of lake and mountain surface connect at different scales to support riparian vegetation. Secondly, we evaluated how these underlying ecotope properties drive the formation of riparian communities and discuss their potential sensitivity to environmental change. At each lake plant taxonomic composition was assessed together with the elemental composition of water and sediment and ecosystem-relevant geographical factors. Their influence on vegetation was modelled using the Fuzzy Set Ordination and conceptually illustrated using network analysis. Hydrology-hydrodynamics was the main catchment-scale factor connecting riparian vegetation with large water fluxes, followed by topography and geomorphology. At macroscale vegetation related to pan-climatic gradients altitude and latitude, which captured, in a relatively narrow geographic area the transition between large European climatic zones. Locally, sediment Mg and Pb and water Mn and Fe were reliable predictors of plant composition, reflecting connections with catchment nutrient availability, and water saturation in the soil. Community analysis identified four riparian groups, characteristic to (a) damp environments, (b) snow bed-silicate bedrock, (c) wet heath, and (d) limestone bedrock. Their distribution along geographic gradients is further explored. With climate change being a serious threat to the alpine biome, this study provides critical information on the linkages between the riparian ecotone and the extended environment, which could prove invaluable in assessing future responses to environmental change.Riparian ecotones are aquatic-terrestrial interfaces integrating climate and nutrient fluxes across landscape physical elements. Despite experiencing severe nutrient and climate constraints, high elevation lakes host highly variable riparian ecosystems. With climate change rapidly encroaching in the alpine biome, it is increasingly vital to understand how natural ecosystem balance is sustained through multi-scale interactions between lake and catchment before major deleterious effects are experienced. A total of 189 glacial origin lakes and ponds in the Central Pyrenees was surveyed to test how lake, catchment, and geographical scale factors interact at different scales to drive riparian vegetation composition. Secondly, we aimed to evaluate how underlying catchment factors influence the formation of riparian plant communities and their potential sensitivity to environmental change. At each lake, plant taxonomic composition was assessed and samples of water and sediment were analysed for major and trace element composition. Ecosystem-relevant local and catchment-scale factors were estimated together with geolocation, and their influence on vegetation was modelled using the logic of Fuzzy Set Ordination. Catchment hydrology-hydrodynamics was the main driver of riparian vegetation structure, followed by topography formation and geomorphology. Although the study area extended over a relatively small geographic extent, the lakes were riparian surface was able to capture the transitional gradient between large pan-European climatic zones. Lake sediment Mg and Pb and water Mn and Fe are reliable indicators of riparian vegetation composition, likely reflecting bedrock geology, and hydrology-driven redox fluctuations in the riparian zone. Community analysis identified four riparian groups, characteristic to (a) damp environments, (b) snow bed-silicate bedrock, (c) wet heath, and (d) limestone bedrock. Their sensitivity to geographic and ecotopic gradients are further evaluated. With climate change threatening major shifts in the alpine biome, the findings provide critical information on how natural riparian ecosystem balance is maintained by multi-scale interactions inside and outside the catchment, and provide invaluable baseline data for better predicting future responses to environmental changes.

Riparian vegetation in the alpine connectome : terrestrial-aquatic and terrestrial-terrestrial interactions

Alpine regions are under increased attention worldwide for their critical role in early biogeochemical cycles, their high sensitivity to environmental change, and as repositories of natural resources of high quality. Their riparian ecosystems, at the interface between aquatic and terrestrial environments, play important geochemical functions in the watershed and are biodiversity hotspots, despite a harsh climate and topographic setting. With climate change rapidly affecting the alpine biome, we still lack a comprehensive understanding of the extent of interactions between riparian surface, lake and catchment environments. A total of 189 glacial - origin lakes were surveyed in the Central Pyrenees to test how key elements of the lake and terrestrial environments interact at different scales to shape riparian plant composition. Secondly, we evaluated how underlying ecotope features drive the formation of natural communities potentially sensitive to environmental change and assessed their habitat distribution. At the macroscale, vegetation composition responded to pan-climatic gradients altitude and latitude, which captured in a narrow geographic area the transition between large European climatic zones. Hydrodynamics was the main catchment-scale factor connecting riparian vegetation with major water fluxes, followed by topography and geomorphology. Lake sediment Mg and Pb, and water Mn and Fe contents reflected local influences from mafic bedrock and soil water saturation. Community analysis identified four keystone ecosystems: (i) damp ecotone, (ii) snow bed-silicate bedrock, (iii) wet heath, and (iv) calcareous substrate. These communities and their connections with ecotope elements could be at risk from a number of environmental change factors including warmer seasons, snow line and lowland species advancement, increased nutrient/metal input and water level fluctuations. The results imply important natural terrestrial-aquatic linkages in the riparian environment at a wide range of scales, which could help better address further biomic impacts of environmental change.

Small lakes in big landscape: External drivers of littoral ecosystem in high elevation lakes

In low nutrient alpine lakes, littoral surfaces are the most productive part of the ecosystem, and they are biodiversity 16 hotspots. It is not entirely known how the nature and properties of lake surrounding catchments, their ecological 17 structure and larger landscape factors work together at different scales to shape the structure and functioning of 18 littoral ecosystems. 19 A total of 114 high altitude lakes and ponds in the central Pyrenees were surveyed to assess the relative 20 control of catchment properties at a variety of scales on littoral zoobenthic communities. At each location benthic 21 invertebrate composition was recorded together with geolocation (altitude, latitude and longitude), composite factors 22 representing hydrodynamics, geo-morphology and topography, riparian vegetation composition, presence of 23 vertebrate predators (trout and frogs), and water pH and conductivity. 24 A two-step fuzzy set ordination (FSO)-multidimensional FSO (MFSO) model integrating benthic biota and 25 environmental variables revealed that at geographic scale, longitude gradient surpassed altitude in its influence on 26 littoral ecosystem, reflecting a transition between Atlantic and Mediteranean biogeographic regions. Within each 27 catchment, topography (through its control of catchment type, shore and catchment snow coverage, and connectivity 28 with other lakes) was the main driver of taxa composition, while hydrodynamics (waterbody size, type and 29 inflow/outflow volumes) was secondary, and strongly covaried with the former. Locally, riparian plant composition 30 was tightly connected with littoral invertebrate community structure, richness and morphotype diversity. These 31 variables work directly and indirectly by creating habitats (for both, aquatic and terrestrial invertebrate stages), 32Graphical abstract: In low nutrient alpine lakes, the littoral zone is the most productive part of the ecosystem, and it is a biodiversity hotspot. It is not entirely clear how the scale and physical heterogeneity of surrounding catchment, its ecological composition, and larger landscape gradients work together to sustain littoral communities. A total of 114 alpine lakes in the central Pyrenees were surveyed to evaluate the functional connectivity between catchment physical and ecological elements and littoral zoobenthos, and ascertain their effect on community formation. At each lake, the zoobenthic composition was assessed together with geolocation (altitude, latitude and longitude), catchment hydrodynamics, geomorphology, topography, riparian vegetation composition, the presence of trout and frogs, water pH and conductivity. Uni- and multidimensional fuzzy set ordination models integrating benthic biota and environmental variables revealed that at geographical scale longitude surpassed altitude in its effect on littoral ecosystem, reflecting a sharp transition between Atlantic and Mediterranean bioregions. Topography (through its control of catchment type, summer snow coverage, and connectivity with other lakes) was the largest catchment-scale driver, followed by hydrodynamics (waterbody size, type and inflow/outflow volumes). Locally, riparian plant composition significantly related to littoral community structure, richness and morphotype diversity. These variables, directly and indirectly create habitats for aquatic and terrestrial stages of invertebrates, and control nutrient and water cycles. Three ecologically diverse associations characterised distinct lake sets. Vertebrate predation, water conductivity and pH (broad measures of total dissolved ions/nutrients and their bioavailability) had no major influence on littoral taxa. The work provides exhaustive information from relatively pristine sites, which unveil a strong connection between littoral ecosystem and catchment heterogeneity at scales beyond the local environment. This underpins their role as sensors of local and large-scale environmental changes, and can be used to evaluate further impacts.

Nodes in the alpine connectome. Exploring the linkages between riparian ecosystem and geo-climatic elements across the mountain environment

Alpine regions are under increased attention worldwide do their role in storing freshwater of high quality and their high sensitivity to climate change - comparable only to the poles. Riparian ecosystems in such regions, integrating water and nutrient fluxes from aquatic and terrestrial environments, host a disproportionally rich biodiversity, despite experiencing severe climate and nutrient restrictions. With climate change rapidly encroaching in the alpine biome, it is important to fully understand how the lake and its surrounding landscape elements sustain such rich ecosystems, before their functional connectivity could be seriously severed. A total of 189 glacial origin lakes in the Central Pyrenees were surveyed to test how key elements of lake and terrestrial environments work together at different scales to shape the riparian plant composition. Secondly, we evaluated how these ecotope features drive the formation of riparian communities potentially sensitive to environmental change, and assessed their habitat distribution. At each lake plant taxonomic composition was assessed together with elemental composition of water and sediment and ecosystem-relevant geographical factors. At macroscale vegetation composition responded to pan-climatic gradients altitude and latitude, which captured, in a narrow geographic area the transition between large European climatic zones. Hydrodynamics was the main catchment-scale factor connecting riparian vegetation with large-scale water fluxes, followed by topography and geomorphology. Lake sediment Mg and Pb, and water Mn and Fe contents reflected local connections with nutrient availability, and water saturation of the substrate. Community analysis identified four keystone plant communities of large niche breadths, present in a wide range of habitats, from (i) damp environments, (ii) snow bed-silicate bedrock, (iii) wet heath, and (iv) limestone bedrock. With environmental change advancing in the alpine biome, this study provides critical information on fundamental linkages between riparian ecosystem and surrounding landscape elements, which could prove invaluable in assessing future biomic impacts. Graphical abstract: Riparian ecosystem of Lake Cardal (0.3ha, 2224m a.s.l) in the Pyrenees National Park (France), with a network diagram of connected landscape elements. Photo by Antonio Palanca-Soler.Riparian ecotones are aquatic-terrestrial interfaces integrating climate and nutrient fluxes across landscape physical elements. Despite experiencing severe nutrient and climate restrictions, high elevation lakes host a disproportionally diverse riparian ecosystem. With climate change rapidly encroaching in the alpine biome, it is vital to understand how the functional connectivity between lakes and their surrounding landscapes maintains a natural ecosystem diversity before they experience major deleterious effects. A total of 189 glacial origin lakes in the Central Pyrenees were surveyed to test how key elements of lake and mountain surface connect at different scales to support riparian vegetation. Secondly, we evaluated how these underlying ecotope properties drive the formation of riparian communities and discuss their potential sensitivity to environmental change. At each lake plant taxonomic composition was assessed together with the elemental composition of water and sediment and ecosystem-relevant geographical factors. Their influence on vegetation was modelled using the Fuzzy Set Ordination and conceptually illustrated using network analysis. Hydrology-hydrodynamics was the main catchment-scale factor connecting riparian vegetation with large water fluxes, followed by topography and geomorphology. At macroscale vegetation related to pan-climatic gradients altitude and latitude, which captured, in a relatively narrow geographic area the transition between large European climatic zones. Locally, sediment Mg and Pb and water Mn and Fe were reliable predictors of plant composition, reflecting connections with catchment nutrient availability, and water saturation in the soil. Community analysis identified four riparian groups, characteristic to (a) damp environments, (b) snow bed-silicate bedrock, (c) wet heath, and (d) limestone bedrock. Their distribution along geographic gradients is further explored. With climate change being a serious threat to the alpine biome, this study provides critical information on the linkages between the riparian ecotone and the extended environment, which could prove invaluable in assessing future responses to environmental change.Riparian ecotones are aquatic-terrestrial interfaces integrating climate and nutrient fluxes across landscape physical elements. Despite experiencing severe nutrient and climate constraints, high elevation lakes host highly variable riparian ecosystems. With climate change rapidly encroaching in the alpine biome, it is increasingly vital to understand how natural ecosystem balance is sustained through multi-scale interactions between lake and catchment before major deleterious effects are experienced. A total of 189 glacial origin lakes and ponds in the Central Pyrenees was surveyed to test how lake, catchment, and geographical scale factors interact at different scales to drive riparian vegetation composition. Secondly, we aimed to evaluate how underlying catchment factors influence the formation of riparian plant communities and their potential sensitivity to environmental change. At each lake, plant taxonomic composition was assessed and samples of water and sediment were analysed for major and trace element composition. Ecosystem-relevant local and catchment-scale factors were estimated together with geolocation, and their influence on vegetation was modelled using the logic of Fuzzy Set Ordination. Catchment hydrology-hydrodynamics was the main driver of riparian vegetation structure, followed by topography formation and geomorphology. Although the study area extended over a relatively small geographic extent, the lakes were riparian surface was able to capture the transitional gradient between large pan-European climatic zones. Lake sediment Mg and Pb and water Mn and Fe are reliable indicators of riparian vegetation composition, likely reflecting bedrock geology, and hydrology-driven redox fluctuations in the riparian zone. Community analysis identified four riparian groups, characteristic to (a) damp environments, (b) snow bed-silicate bedrock, (c) wet heath, and (d) limestone bedrock. Their sensitivity to geographic and ecotopic gradients are further evaluated. With climate change threatening major shifts in the alpine biome, the findings provide critical information on how natural riparian ecosystem balance is maintained by multi-scale interactions inside and outside the catchment, and provide invaluable baseline data for better predicting future responses to environmental changes.