Community structure of benthic invertebrates in the Allipén River basin, North Patagonia, Araucania region (38º S, Chile)

One of the biological indicators most used to determine the health of a fluvial ecosystem are the benthic macroinvertebrates. The presence of recurrent species in a wide gradient of latitudes, dominates the biogeographic pattern of the benthic macroinvertebrates in Chilean fresh waters, nevertheless the knowledge on the communitarian ecology of these in the Chilean rivers continues to be scarce. Null models became a powerful statistical tool for describing the ecological mechanisms that drive the structure of an ecological community and the underlying patterns of diversity. The objective of this study was to determine the community structure of benthic invertebrates in the Allipén River by describing their composition, richness and abundance of species through richness models and null models based on presence/absence. The results reveal a high family richness and low diversity, three phyla, five classes, 11 orders and 28 families were identified in the study area during the four seasons of the year. The Arthropoda phylum was the most representative in abundance and richness. Regarding to richness, Trichoptera (7 families) and Diptera (6 families) followed by Ephemeroptera (3 families) were the orders that showed the greatest diversity of families, however, a low diversity with a H’≤ 1.5 nit was registered in the study area. We demonstrated through the null models, the randomization in the species associations corresponding to the three analyzed sites. The information provided here contributes to the understanding of the ecological patterns of the invertebrate communities in the Allipén River, establishing the basis for more complex ecological studies.

Monitoring soil retention properties in a riverbank susceptible to fluvial erosion

<p>One of the principal source of vulnerability for riverbanks is given by slopes instabilities, which is triggered on the riverside by fluvial erosion. In order to mitigate such erosion, the establishment of a dense herbaceous cover aims at promoting the slope protection and reducing the likelihood of embankment failure. In fact, the aerial parts of vegetation reduce the mechanical impact of river level fluctuations and rainfall on the embankment and retain sediment transported, while the belowground parts reinforce mechanically the materials forming the top of the embankment, facilitating drainage in the topmost layers and promoting plant water uptake, thus contributing to the regulation of the drying/wetting cycle.</p><p>Plating deep-rooting perennial, herbaceous species on earth embankments therefore represent a sustainable, green intervention for the protection of a riverbank susceptible to fluvial erosion, contributing to the preservation of the fluvial ecosystem environment and avoiding a wide use of grey solutions. The European research project OPERANDUM is testing also this typology of NBS, with an experimental site selected on the river Panaro, one of the main tributary of the main Po River, Italy. To investigate the effect of vegetation on the riverbank soil, a monitoring system has been installed at shallow depths. The system estimates soil water content, matric suction and pore water pressure, in order to quantify the effects of the growth of different vegetation species, which have been recently seeded on site, for analyzing the plant-soil-atmosphere interaction. The work will present the site preparation and the system implementation. The analysis of the first collected data and the outcomes of the preliminary investigations, including site and laboratory experiments, will then be discussed. Monitoring data collected along the entire vegetation growth cycle, that is expected to take around two years, will allow to quantify the influence of vegetation in the soil-atmosphere interaction processes and, on the long-term, verify its effective contribution in riverbank protection.</p>

Wildfire-Derived Pyrogenic Carbon Modulates Organic Matter and Microbial Functioning in a Fluvial Ecosystem

Wildfires produce large amounts of pyrogenic carbon (PyC), including particulate charcoal, known for its chemical recalcitrance and sorption affinity for organic molecules. Wildfire-derived PyC is highly mobile in the landscape and can be transported to fluvial networks where it may impact natural dissolved organic matter (DOM) and microbial biofilms. The effects of PyC on freshwater ecosystems and carbon cycling therein remain poorly investigated. To address this research gap, we used in-stream flumes with a control vs treatment design (pulse addition of PyC particles). We present evidence that field-aged PyC inputs into river ecosystems can alter dissolved organic carbon (DOC) concentration, DOM composition, pH, and enzymatic activities in benthic biofilms. In stream DOM composition was altered due to leaching of pyrogenic DOM from PyC and possible concurrent sorption of riverine DOM to PyC. DOM changes and increase in pH were associated with changes in enzymatic activities, which reflected preferential usageof recalcitrant over easily available DOM by biofilms. Furthermore, we observed particulate PyC sedimentation on biofilm surfaces, which may further modulate the impacts of PyC. This study highlights the importance of PyC for in-stream DOM propertiesand biofilm functioning with implications for in-stream biogeochemical cycling in fire affected watersheds. <br>

Wildfire-Derived Pyrogenic Carbon Modulates Organic Matter and Microbial Functioning in a Fluvial Ecosystem

Wildfires produce large amounts of pyrogenic carbon (PyC), including particulate charcoal, known for its chemical recalcitrance and sorption affinity for organic molecules. Wildfire-derived PyC is highly mobile in the landscape and can be transported to fluvial networks where it may impact natural dissolved organic matter (DOM) and microbial biofilms. The effects of PyC on freshwater ecosystems and carbon cycling therein remain poorly investigated. To address this research gap, we used in-stream flumes with a control vs treatment design (pulse addition of PyC particles). We present evidence that field-aged PyC inputs into river ecosystems can alter dissolved organic carbon (DOC) concentration, DOM composition, pH, and enzymatic activities in benthic biofilms. In stream DOM composition was altered due to leaching of pyrogenic DOM from PyC and possible concurrent sorption of riverine DOM to PyC. DOM changes and increase in pH were associated with changes in enzymatic activities, which reflected preferential usageof recalcitrant over easily available DOM by biofilms. Furthermore, we observed particulate PyC sedimentation on biofilm surfaces, which may further modulate the impacts of PyC. This study highlights the importance of PyC for in-stream DOM propertiesand biofilm functioning with implications for in-stream biogeochemical cycling in fire affected watersheds. <br>

Sustainability Analysis of the M-30 Madrid Tunnels and Madrid Río after 14 years of Service Life

In 2007, the excavation of the M-30 ring road located in Madrid and the creation of a green corridor either side of the Manzanares river brought significant change to the metropolitan area. The corridor and linear park which it provided were designed to contribute to the regeneration of the fluvial ecosystem, establish links among residents on each side of the river and promote cultural and leisure activities. This paper provides a sustainability analysis of the excavation of the M-30 (involving the socio-economic and environmental impact) 14 years after its construction. In order to show such an impact, an analysis of the area both prior to the project and after completion, as well as a hypothetical solution that uses improved materials, has been performed. This entails use of the multi-criteria decision-making model named MIVES (initials in Spanish, modelo integrado de valor para una evaluación sostenible). The MIVES method is based on the application of value functions of sustainability indicators selected by socio-economic and environmental criteria, chosen by experts. Results from analysis showed that the excavation of the M-30 considerably improved the sustainability of the area (sustainable index 3.43 and 6.26 both before and after the excavation works). However, use of improved materials in contrast with the application of conventional materials slightly improved the sustainability of the work (Sustainability Index 6.26 and 6.74, respectively, of the conventional materials).

Sustainability Analysis of the M-30 Madrid Tunnels and Madrid Río through the MIVES Method After 14 Years of Service Life

In 2007, the excavation of the M-30 ring road located in Madrid and the creation of a green corridor either side of the Manzanares river brought significant change to the metropolitan area. The corridor and linear park which it provided were designed to contribute to the regeneration of the fluvial ecosystem, establish links among residents on each side of the river and promote cultural and leisure activities. This paper provides a sustainability analysis of the excavation of the M-30 (involving the socio-economic and environmental impact) 14 years after its construction. In order to show such an impact, an analysis of the area both prior to the project and after completion, as well as a hypothetical solution that uses improved materials, has been performed. This entails use of the multi-criteria decision-making model named MIVES (initials in Spanish, modelo integrado de valor para una evaluaci&oacute;n sostenible). The MIVES method is based on the application of value functions of sustainability indicators selected by socio-economic and environmental criteria, chosen by experts. Results from analysis showed that the excavation of the M-30 considerably improved the sustainability of the area (sustainable index 3.43 and 6.26 both before and after the excavation works). However, use of improved materials in contrast with the application of conventional materials slightly improved the sustainability of the work (Sustainability Index 6.26 and 6.74, respectively, of the conventional materials).

Odonata Recorded in the Buffer Zone of Mt. Hamiguitan Range Wildlife Sanctuary with Remarks on the Distribution of Endangered Risiocnemis antoniae in Davao Oriental Philippines

Mt. Hamiguitan Range Wildlife Sanctuary is both a UNESCO and ASEAN recognised heritage site. There is a current move to expand the site by expanding the buffer zone. This area unfortunately is poorly studied in terms of its biodiversity. This paper explores the odonata species found in the proposed buffer zone. Transect line along fluvial ecosystem was established in the two bordering municipalities. A total of 32 species from 22 genera and nine families were recorded in which eighteen species (18) belong to the suborder Zygoptera while 14 species are Anisoptera. High level of endemism was recorded for Zygoptera (94.44%) endemism while low endemism for Anisoptera (21.43%). Distribution of Risiocnemis antoniea (Gassmann and Hämäläinen, 2002), an IUCN endangered damselfly was recorded in the creeks of Barangay Tandang Sora, Governor Generoso at relatively lower elevation between 100-300 meters above sea level. Due to its habitat’s close proximity to human habitation and the encroaching anthropogenic disturbances, it should be declared as Local Conservation Area.

Human signatures derived from nighttime lights along the Eastern Alpine river network in Austria and Italy

Understanding how human settlements and economic activities are distributed with reference to the geographical location of streams and rivers is of fundamental relevance for several issues, such as flood risk management, drought management related to increased water demands by human population, fluvial ecosystem services, water pollution and water exploitation. Besides the spatial distribution, the evolution in time of the human presence constitutes an additional key question. This work aims at understanding and analysing the spatial and temporal evolution of human settlements and associated economic activity, derived from nighttime lights, in the Eastern Alpine region. Nightlights, available at a fine spatial resolution and for a 22-year period, constitute an excellent data base, which allows one to explore in details human signatures. In this experiment, nightlights are associated to five distinct distance-from-river classes. Our results clearly point out an overall enhancement of human presence across the considered distance classes during the last 22 years, though presenting some differences among the study regions. In particular, the river network delineation, by considering different groups of river pixels based on the Strahler order, is found to play a central role in the identification of nightlight spatio-temporal trends.

The inbuilt long-term unfeasibility of environmental flows when disregarding riparian vegetation requirements

Environmental flows remain biased towards the traditional fish biological group and ignore the inter-annual flow variability that rules longer species life cycles, thus disregarding the long-term perspective of the riverine ecosystem. Incorporating riparian vegetation requirements into environmental flows could bring an important contribute to fill in this gap. The long-term after-effects of this shortcoming on the biological communities downstream of dams were never estimated before. We address this concern by evaluating the effects of environmental flow regimes disregarding riparian vegetation in the long-term perspective of the fluvial ecosystem. To achieve that purpose, the riparian vegetation evolution was modeled considering its structural response to a decade of different environmental flows, and the fish habitat availability was assessed for each of the resulting riparian habitat scenarios. We demonstrate that fish habitat availability changes accordingly to the long-term structural adjustments that riparian habitat endure following river regulation. Environmental flow regimes considering only aquatic biota become obsolete in few years due to the change of the habitat premises in which they were based on and, therefore, are unsustainable in the long run. Therefore, considering riparian vegetation requirements on environmental flows is mandatory to assure the effectiveness of those in the long-term perspective of the fluvial ecosystem.