Journal articles: 'Stream ecosystem'

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Minshall, G. Wayne, Kenneth W. Cummins, Robert C. Petersen, Colbert E. Cushing, Dale A. Bruns, James R. Sedell, and Robin L. Vannote. "Developments in Stream Ecosystem Theory." Canadian Journal of Fisheries and Aquatic Sciences 42, no. 5 (May 1, 1985): 1045–55. http://dx.doi.org/10.1139/f85-130.

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Four significant areas of thought, (1) the holistic approach, (2) the linkage between streams and their terrestrial setting, (3) material cycling in open systems, and (4) biotic interactions and integration of community ecology principles, have provided a basis for the further development of stream ecosystem theory. The River Continuum Concept (RCC) represents a synthesis of these ideas. Suggestions are made for clarifying, expanding, and refining the RCC to encompass broader spatial and temporal scales. Factors important in this regard include climate and geology, tributaries, location-specific lithology and geomorphology, and long-term changes imposed by man. It appears that most riverine ecosystems can be accommodated within this expanded conceptual framework and that the RCC continues to represent a useful paradigm for understanding and comparing the ecology of streams and rivers.

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Jennings, Jean-Jacques, and Avital Gasith. "Spatial and Temporal Changes in Habitat Conditions in the Na'aman Stream Ecosystem, Israel." Water Science and Technology 27, no. 7-8 (April 1, 1993): 387–95. http://dx.doi.org/10.2166/wst.1993.0574.

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Nahal Na'aman is a small, shallow coastal stream in northern Israel. A three year study was conducted to examine the effect of habitat conditions on the biological structure and function of the stream ecosystem. Here we describe temporal and spatial changes in the water regime and water quality as measures of the stream's habitat conditions. Habitat condition is strongly influenced by the hydrological regime and the water quality. In dry years the water level drops and the upper section of the stream may dry up completely. Inflow of polluted water from various sources increasingly reduces water quality downstream. In general, the Na'aman may be categorized as oligo- to mesohaline stream, highly enriched with organic matter and nutrients. Sporadic pollution events markedly affect the water quality resulting in hypertrophic conditions, particularly at times of low stream levels. Low water quality was detected also in association with the drying and refilling of the stream's sections in late summer and in fall, respectively, and following runoff in winter. The oligohaine nature of the stream a priori reduces species diversity relative to other freshwater, lowland streams/Based on water quality conditions, highest species diversity may be expected in the spring area and the upper section of the stream. However, habitat conditions in this section are most unstable due to changes of the hydrological regime. This, in turn, is expected to further reduce species richness and diversity. The extreme conditions are expected to determine the limit for the development of plant and animal life in the stream. This study illustrates the inherent problems of the coastal streams of Israel, namely, diminishing natural flow which is often replaced by discharge of effluent or sewage. Rehabilitation of the Na'aman and other coastal streams demands a radical solution for these problems.

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Ferreira, Verónica, Arturo Elosegi, Scott D. Tiegs, Daniel von Schiller, and Roger Young. "Organic Matter Decomposition and Ecosystem Metabolism as Tools to Assess the Functional Integrity of Streams and Rivers–A Systematic Review." Water 12, no. 12 (December 15, 2020): 3523. http://dx.doi.org/10.3390/w12123523.

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Streams and rivers provide important services to humans, and therefore, their ecological integrity should be a societal goal. Although ecological integrity encompasses structural and functional integrity, stream bioassessment rarely considers ecosystem functioning. Organic matter decomposition and ecosystem metabolism are prime candidate indicators of stream functional integrity, and here we review each of these functions, the methods used for their determination, and their strengths and limitations for bioassessment. We also provide a systematic review of studies that have addressed organic matter decomposition (88 studies) and ecosystem metabolism (50 studies) for stream bioassessment since the year 2000. Most studies were conducted in temperate regions. Bioassessment based on organic matter decomposition mostly used leaf litter in coarse-mesh bags, but fine-mesh bags were also common, and cotton strips and wood were frequent in New Zealand. Ecosystem metabolism was most often based on the open-channel method and used a single-station approach. Organic matter decomposition and ecosystem metabolism performed well at detecting environmental change (≈75% studies), with performances varying between 50 and 100% depending on the type of environmental change; both functions were sensitive to restoration practices in 100% of the studies examined. Finally, we provide examples where functional tools are used to complement the assessments of stream ecological integrity. With this review, we hope to facilitate the widespread incorporation of ecosystem processes into bioassessment programs with the broader aim of more effectively managing stream and river ecosystems.

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Hornbach, Daniel J. "Multi-Year Monitoring of Ecosystem Metabolism in Two Branches of a Cold-Water Stream." Environments 8, no. 3 (February 28, 2021): 19. http://dx.doi.org/10.3390/environments8030019.

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Climate change is likely to have large impacts on freshwater biodiversity and ecosystem function, especially in cold-water streams. Ecosystem metabolism is affected by water temperature and discharge, both of which are expected to be affected by climate change and, thus, require long-term monitoring to assess alterations in stream function. This study examined ecosystem metabolism in two branches of a trout stream in Minnesota, USA over 3 years. One branch was warmer, allowing the examination of elevated temperature on metabolism. Dissolved oxygen levels were assessed every 10 min from spring through fall in 2017–2019. Gross primary production (GPP) was higher in the colder branch in all years. GPP in both branches was highest before leaf-out in the spring. Ecosystem respiration (ER) was greater in the warmer stream in two of three years. Both streams were heterotrophic in all years (net ecosystem production—NEP < 0). There were significant effects of temperature and light on GPP, ER, and NEP. Stream discharge had a significant impact on all GPP, ER, and NEP in the colder stream, but only on ER and NEP in the warmer stream. This study indicated that the impacts of temperature, light, and discharge differ among years, and, at least at the local scale, may not follow expected patterns.

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Walsh, Christopher J., Tim D. Fletcher, and Geoff J. Vietz. "Variability in stream ecosystem response to urbanization." Progress in Physical Geography: Earth and Environment 40, no. 5 (October 2016): 714–31. http://dx.doi.org/10.1177/0309133316671626.

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The geomorphic and ecological degradation of streams resulting from urbanization is well recognized. Recent reviews have hypothesized variability in ecological response to urbanization among stream types and among regions with varying climate and catchment soil and geology. Testing such hypotheses will be aided by the use of consistent metrics of the primary processes that drive urban-induced degradation of streams. We thus developed an urban typology distinguishing the common classes of urban land and water management that are hypothesized to have different effects on stream ecosystems. In developing the typology, we identify and emphasize the importance of step changes (thresholds) in the hydrologic consequences of urbanization, the often-unrecognized massive increase in drainage density of urban catchments, the difficulty in setting reference condition for many cities and the resulting difficulties in comparing responses to urbanization among cities. We critically assess the evidence for variability in responses to urbanization and its causes, and conclude that there are few studies demonstrating intra- or inter-regional differences in response to urbanization that have adequately accounted for the influence of potential differences in urban land and water management. We use the urban typology to propose metrics to allow such accounting, which we argue is necessary to advance management for stream protection and restoration.

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Brunner, Franziska S., Jaime M. Anaya-Rojas, Blake Matthews, and Christophe Eizaguirre. "Experimental evidence that parasites drive eco-evolutionary feedbacks." Proceedings of the National Academy of Sciences 114, no. 14 (March 20, 2017): 3678–83. http://dx.doi.org/10.1073/pnas.1619147114.

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Host resistance to parasites is a rapidly evolving trait that can influence how hosts modify ecosystems. Eco-evolutionary feedbacks may develop if the ecosystem effects of host resistance influence selection on subsequent host generations. In a mesocosm experiment, using a recently diverged (<100 generations) pair of lake and stream three-spined sticklebacks, we tested how experimental exposure to a common fish parasite (Gyrodactylus spp.) affects interactions between hosts and their ecosystems in two environmental conditions (low and high nutrients). In both environments, we found that stream sticklebacks were more resistant to Gyrodactylus and had different gene expression profiles than lake sticklebacks. This differential infection led to contrasting effects of sticklebacks on a broad range of ecosystem properties, including zooplankton community structure and nutrient cycling. These ecosystem modifications affected the survival, body condition, and gene expression profiles of a subsequent fish generation. In particular, lake juvenile fish suffered increased mortality in ecosystems previously modified by lake adults, whereas stream fish showed decreased body condition in stream fish-modified ecosystems. Parasites reinforced selection against lake juveniles in lake fish-modified ecosystems, but only under oligotrophic conditions. Overall, our results highlight the overlapping timescales and the interplay of host–parasite and host–ecosystem interactions. We provide experimental evidence that parasites influence host-mediated effects on ecosystems and, thereby, change the likelihood and strength of eco-evolutionary feedbacks.

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Gkiatas, G., I. Kasapidis, P. Koutalakis, V. Iakovoglou, A. Savvopoulou, I. Germantzidis, and G. N. Zaimes. "Enhancing urban and sub-urban riparian areas through ecosystem services and ecotourism activities." Water Supply 21, no. 6 (April 16, 2021): 2974–88. http://dx.doi.org/10.2166/ws.2021.114.

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Abstract Riparian ecosystems in urban environments are usually degraded. Their sustainable management can reduce water pollution, mitigate climate change while providing recreation opportunities. This study assessed the current condition of the streams/torrents and their riparian areas in the city of Drama in Greece. In addition, practices to improve their functionality and enhance community awareness were recommended. A spatial database of the wider urban setting including suburbs and rural areas (weather, land cover, soils, roads, protected areas, riparian areas, etc.) was developed within GIS. The datasets were then inputted in a hydrologic model to simulate the water balance and stream discharge in the main urban streams and torrents. Field measurements of stream water discharge, and vegetation and stream channel conditions were undertaken using two visual protocols. The results of the protocols indicate that most streams/torrents and their riparian areas are of low ecological quality. Nature-based solutions were recommended to improve their ecological quality. In addition, the implementation of Eco-Routes was recommended to enhance the awareness of their importance and to promote their sustainable management. Overall, the urban streams/torrents and riparian ecosystems of Drama are degraded and innovative management practices should be implemented to conserve them and feature their ecosystem services.

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Adhikari, Namita Paudel, Subash Adhikari, and Ganesh Paudel. "Bacterial Diversity in Aquatic Ecosystems over the Central Himalayas, Nepal: Progress and Future Perspectives." Janapriya Journal of Interdisciplinary Studies 8 (December 31, 2019): 200–211. http://dx.doi.org/10.3126/jjis.v8i0.27319.

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Nepal hosts a large area of freshwater aquatic ecosystem including glacier associated system like glacier-fed streams and lakes as well as stream fed lowland lakes. Bacteriological studies are very important in aquatic ecosystems as bacteria are the major participants in biogeochemical cycles and food web structures. This study reviewed available literature in bacteriological studies of aquatic ecosystems in the Central Himalayas, Nepal and revealed that such studies are very limited. Thus, we conclude that future research works need to proceed through the latest molecular methods with high throughput technique using multiple environmental factors in the aquatic ecosystem.

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Ludlam, John P., and Allison H. Roy. "Understanding effects of small dams on benthic metabolism and primary production in temperate forested streams." Fundamental and Applied Limnology / Archiv für Hydrobiologie 193, no. 3 (April 21, 2020): 227–37. http://dx.doi.org/10.1127/fal/2020/1260.

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Dams can alter the chemical and physical conditions of downstream environments by increasing stream temperatures, altering nutrient limitation, reducing flow variability, and reducing fine sediment deposition. However, little is known about how fundamental stream ecosystem processes like productivity and respiration respond to dams. Nutrient diffusing substrates were installed in three dam streams and three control streams to evaluate the effect of dams on benthic gross primary productivity (GPP), respiration (R), and chlorophyll α production. Dam streams were an average of 5.6 °C warmer than control streams but GPP, R and chlorophyll α were not different between control and dam streams. Phosphorus enrichment increased heterotrophic R relative to controls (~1.8×) but not autotrophic GPP, R or chlorophyll α. Stream nutrient concentrations and nutrient limitation of heterotrophic R were similar in dam and control streams, suggesting that the dams had limited effects on nutrient transport downstream. Autotrophic GPP, R and chlorophyll α were limited by light and varied within and across streams, potentially masking our ability to detect differences caused solely by dams. Dams may alter stream ecosystem func- tion but consideration of other factors associated with and independent of dams is critical for predicting ecosystem responses to dams.

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Palmer, Margaret, and Albert Ruhi. "Linkages between flow regime, biota, and ecosystem processes: Implications for river restoration." Science 365, no. 6459 (September 19, 2019): eaaw2087. http://dx.doi.org/10.1126/science.aaw2087.

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River ecosystems are highly biodiverse, influence global biogeochemical cycles, and provide valued services. However, humans are increasingly degrading fluvial ecosystems by altering their streamflows. Effective river restoration requires advancing our mechanistic understanding of how flow regimes affect biota and ecosystem processes. Here, we review emerging advances in hydroecology relevant to this goal. Spatiotemporal variation in flow exerts direct and indirect control on the composition, structure, and dynamics of communities at local to regional scales. Streamflows also influence ecosystem processes, such as nutrient uptake and transformation, organic matter processing, and ecosystem metabolism. We are deepening our understanding of how biological processes, not just static patterns, affect and are affected by stream ecosystem processes. However, research on this nexus of flow-biota-ecosystem processes is at an early stage. We illustrate this frontier with evidence from highly altered regulated rivers and urban streams. We also identify research challenges that should be prioritized to advance process-based river restoration.

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Palmer, Margaret A., Solange Filoso, and Rosemary M. Fanelli. "From ecosystems to ecosystem services: Stream restoration as ecological engineering." Ecological Engineering 65 (April 2014): 62–70. http://dx.doi.org/10.1016/j.ecoleng.2013.07.059.

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Jankowski, Kathi Jo, Linda A. Deegan, Christopher Neill, Hillary L. Sullivan, Paulo Ilha, Leonardo Maracahipes-Santos, Nubia Marques, and Marcia N. Macedo. "Land Use Change Influences Ecosystem Function in Headwater Streams of the Lowland Amazon Basin." Water 13, no. 12 (June 15, 2021): 1667. http://dx.doi.org/10.3390/w13121667.

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Intensive agriculture alters headwater streams, but our understanding of its effects is limited in tropical regions where rates of agricultural expansion and intensification are currently greatest. Riparian forest protections are an important conservation tool, but whether they provide adequate protection of stream function in these areas of rapid tropical agricultural development has not been well studied. To address these gaps, we conducted a study in the lowland Brazilian Amazon, an area undergoing rapid cropland expansion, to assess the effects of land use change on organic matter dynamics (OM), ecosystem metabolism, and nutrient concentrations and uptake (nitrate and phosphate) in 11 first order streams draining forested (n = 4) or cropland (n = 7) watersheds with intact riparian forests. We found that streams had similar terrestrial litter inputs, but OM biomass was lower in cropland streams. Gross primary productivity was low and not different between land uses, but ecosystem respiration and net ecosystem production showed greater seasonality in cropland streams. Although we found no difference in stream concentrations of dissolved nutrients, phosphate uptake exceeded nitrate uptake in all streams and was higher in cropland than forested streams. This indicates that streams will be more retentive of phosphorus than nitrogen and that if fertilizer nitrogen reaches streams, it will be exported in stream networks. Overall, we found relatively subtle differences in stream function, indicating that riparian buffers have thus far provided protection against major functional shifts seen in other systems. However, the changes we did observe were linked to watershed scale shifts in hydrology, water temperature, and light availability resulting from watershed deforestation. This has implications for the conservation of tens of thousands of stream kilometers across the expanding Amazon cropland region.

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Clancy, Niall G., Janice Brahney, James Dunnigan, and Phaedra Budy. "Effects of a diatom ecosystem engineer (Didymosphenia geminata) on stream food webs: implications for native fishes." Canadian Journal of Fisheries and Aquatic Sciences 78, no. 2 (February 2021): 154–64. http://dx.doi.org/10.1139/cjfas-2020-0121.

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Stream habitat changes affecting primary consumers often indirectly impact secondary consumers such as fishes. Blooms of the benthic algae Didymosphenia geminata (Didymo) are known to affect stream macroinvertebrates, but the potential indirect trophic impacts on fish consumers are poorly understood. In streams of the Kootenai River basin, we quantified the diet, condition, and growth rate of species of trout, char, and sculpin. In 2018, macroinvertebrate taxa composition was different between a stream with Didymo and a stream without, but trout diets, energy demand, and growth rates were similar. Trout abundance was higher in the stream with Didymo, but the amount of drifting invertebrates was higher in the stream without. In 2019, we surveyed 28 streams with a gradient of coverage. Didymo abundance was correlated only with the percentage of aquatic invertebrates in trout diets and was not related to diets of char or sculpin or condition of any species. Thus, we found no evidence for a trophic link between Didymo blooms and the condition or growth of trout, char, or sculpin in mountainous headwater streams.

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Lee, Jong-Won, Sang-Woo Lee, Soon-Jin Hwang, Min-Ho Jang, Doo-Hee Won, Kyung-Jin An, Hye-Jin Park, and Junga Lee. "Establishing Diagnosis Systems for Impaired Stream Ecosystem using Stream/River Ecosystem Survey and Health Assessment." Korean Journal of Ecology and Environment 53, no. 1 (March 31, 2020): 1–10. http://dx.doi.org/10.11614/ksl.2020.53.1.001.

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Doehring, Katharina, Joanne E. Clapcott, and Roger G. Young. "Assessing the Functional Response to Streamside Fencing of Pastoral Waikato Streams, New Zealand." Water 11, no. 7 (June 29, 2019): 1347. http://dx.doi.org/10.3390/w11071347.

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In New Zealand, streamside fencing is a well-recognised restoration technique for pastoral waterways. However, the response of stream ecosystem function to fencing is not well quantified. We measured the response to fencing of eight variables describing ecosystem function and 11 variables describing physical habitat and water quality at 11 paired stream sites (fenced and unfenced) over a 30-year timespan. We hypothesised that (1) fencing would improve the state of stream ecosystem health as described by physical, water quality and functional indicators due to riparian re-establishment and (2) time since fencing would increase the degree of change from impacted to less-impacted as described by physical, water quality and functional indicators. We observed high site-to-site variability in both physical and functional metrics. Stream shade was the only measure that showed a significant difference between treatments with higher levels of shade at fenced than unfenced sites. Cotton tensile-strength loss was the only functional measurement that indicated a response to fencing and increased over time since treatment within fenced sites. Our results suggest that stream restoration by fencing follows a complex pathway, over a space-for-time continuum, illustrating the overarching catchment influence at a reach scale. Small-scale (less than 2% of the upstream catchment area) efforts to fence the riparian zones of streams appear to have little effect on ecosystem function. We suggest that repeated measures of structural and functional indicators of ecosystem health are needed to inform robust assessments of stream restoration.

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Stevenson, R. Jan. "Resource Thresholds and Stream Ecosystem Sustainability." Journal of the North American Benthological Society 16, no. 2 (June 1997): 410–24. http://dx.doi.org/10.2307/1468027.

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Meyer, Judy L., Michael J. Paul, and W. Keith Taulbee. "Stream ecosystem function in urbanizing landscapes." Journal of the North American Benthological Society 24, no. 3 (September 2005): 602–12. http://dx.doi.org/10.1899/04-021.1.

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Minshall, G. Wayne. "Stream Ecosystem Theory: A Global Perspective." Journal of the North American Benthological Society 7, no. 4 (December 1988): 263–88. http://dx.doi.org/10.2307/1467294.

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Brussock, Peter P., Arthur V. Brown, and John C. Dixon. "CHANNEL FORM AND STREAM ECOSYSTEM MODELS." Journal of the American Water Resources Association 21, no. 5 (October 1985): 859–66. http://dx.doi.org/10.1111/j.1752-1688.1985.tb00180.x.

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Sweeney, B. W., T. L. Bott, J. K. Jackson, L. A. Kaplan, J. D. Newbold, L. J. Standley, W. C. Hession, and R. J. Horwitz. "Riparian deforestation, stream narrowing, and loss of stream ecosystem services." Proceedings of the National Academy of Sciences 101, no. 39 (September 20, 2004): 14132–37. http://dx.doi.org/10.1073/pnas.0405895101.

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Scanes, Peter Raymond, Adam McSorley, and Adrian Dickson. "Feral horses (Equus caballus) increase suspended sediment in subalpine streams." Marine and Freshwater Research 72, no. 9 (2021): 1290. http://dx.doi.org/10.1071/mf20353.

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Feral horses preferentially utilise aquatic landscape elements. Damage to stream banks by feral horses potentially degrades water quality and affects aquatic ecosystems. Despite the global predominance of horse activity in or near water, there is poor understanding of in-stream impacts. Motion-sensing cameras were used near subalpine streams to quantify frequency and behaviour of horses interacting with streams. Deployed turbidity loggers were used to indicate the presence of suspended sediment from interactions and to assess long-term (3 year) seasonal suspended sediment regime at sites with very small and large amounts of horse activity. In summer, 99.9% of large grazer interactions with streams were horses and we estimate 130 horse interactions per kilometre of stream per day, resulting in stream turbidity increases up to 100 NTU. Long-term turbidity at sites with greater riparian damage from horses was significantly greater than at control sites. Turbidity in horse-affected streams peaked at 50 times the national turbidity guideline and, in summer, averaged eight times the guideline. Suspended sediment leads to a high risk of loss of aquatic diversity and impairment of ecosystem function. Linear relationships between turbidity and riparian damage suggest that any level of horse presence affects subalpine waterways.

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Peterson, Bruce J., John E. Hobbie, and Teresa L. Corliss. "Carbon Flow in a Tundra Stream Ecosystem." Canadian Journal of Fisheries and Aquatic Sciences 43, no. 6 (June 1, 1986): 1259–70. http://dx.doi.org/10.1139/f86-156.

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The carbon cycle of the Kuparuk River, a meandering tundra stream, is dominated by inputs of eroding peat and leaching dissolved organic carbon from the tundra. Net production of epilithic algae is about 13 g C∙m−2∙yr−1, an order of magnitude less than inputs of allochthonous particulate organic carbon and two orders of magnitude less than inputs of dissolved organic carbon. The streamwater has a mean total organic carbon concentration of 6.8 mg∙L−1, and the annual export of organic carbon from the watershed is 2–3 t∙km−2∙yr−1; both are similar to the average for temperate streams. However, because of the low primary productivity of tundra vegetation, the export of organic carbon from the watershed via the river is a larger fraction (2–6%) of the total watershed net primary production than the 0.1–0.4% usually found for temperate rivers.

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Athanasiadou, Eleni A., Maria Tratsela, and Eleni Gkrimpa. "The Value and Services of Urban Stream Polygnotou, Thessaloniki." Proceedings 2, no. 11 (September 10, 2018): 576. http://dx.doi.org/10.3390/proceedings2110576.

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Grey, blue and green infrastructure supports socio-ecological processes the city undergoes. Yet, procedures of constructing anthropogenic habitats often undermine the value of natural landscape elements such as urban streams. Thessaloniki’s backbone comprises of urban streams that run from the suburban forest of ‘Seih-Sou’ to the Thermaikos Gulf acting as corridors of the natural urban matrix. Policies of the past have dealt with urban streams through extensive engineering drainage methods, eliminating the risk of flooding, yet resulting in rapid stormwater runoff, water quality problems, disturbed riparian ecosystems, leading to the urban stream syndrome. Furthermore, they have failed to address urban streams as an inseparable part of the landscape and thus to incorporate them in people’s mental map and everyday activities. The paper discusses the case of ‘Polygnotou stream’ which forms the beginning of the large scale engineered peripheral moat of Thessaloniki, constructed in the 60’s, and playing the role of the water recipient for six urban streams in total. It falls unknown to the majority of people living in the area, yet its services as an ecosystem ought to be acknowledged, helping inform decision makers of its socio-ecologic, perceptual and economic value. In addition, Polygnotou stream, adjacent streams and the peripheral moat overall, could be considered as a touristic product of great importance.

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Lamberti, Gary A., Stanley V. Gregory, Linda R. Ashkenas, Randall C. Wildman, and Kelly M. S. Moore. "Stream Ecosystem Recovery Following a Catastrophic Debris Flow." Canadian Journal of Fisheries and Aquatic Sciences 48, no. 2 (February 1, 1991): 196–208. http://dx.doi.org/10.1139/f91-027.

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We studied recovery processes for 3 yr in Quartz Creek (Cascade Mountains, Oregon), a third-order stream catastrophically impacted by a February 1986 debris flow for which both predisturbance data and an upstream control reach were available. The debris flow altered channel geomorphology and destroyed riparian vegetation for 500 m, resulting in a reach with short, disordered channel units, low hydraulic retention, and an open canopy. High irradiance levels and reduced grazing by macroinvertebrates contributed to rapid accrual of benthic algae in the disturbed reach, which formed the bioenergetic basis for ecosystem recovery. Macroinvertebrates (mostly herbivores) recovered to upstream densities and taxonomic richness within 1 yr, although effects on community structure persisted into the second year. Cutthroat trout (Oncorhynchus clarki) populations were locally decimated by the disturbance, but by the following year, recruitment of young-of-the-year trout into the reach exceeded that of the upstream reach and populations had recovered to predisturbance densities. Despite the general rapid recovery of the biota within the disturbed reaches, most populations showed broad temporal fluctuations in abundance, suggesting that ecosystem stability was diminished by the debris flow. Long-term monitoring of Quartz Creek may yield additional insight into the role of episodic disturbance in stream ecosystems.

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Bekliz, Meriem, Jade Brandani, Massimo Bourquin, Tom J. Battin, and Hannes Peter. "Benchmarking protocols for the metagenomic analysis of stream biofilm viromes." PeerJ 7 (December 20, 2019): e8187. http://dx.doi.org/10.7717/peerj.8187.

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Viruses drive microbial diversity, function and evolution and influence important biogeochemical cycles in aquatic ecosystems. Despite their relevance, we currently lack an understanding of their potential impacts on stream biofilm structure and function. This is surprising given the critical role of biofilms for stream ecosystem processes. Currently, the study of viruses in stream biofilms is hindered by the lack of an optimized protocol for their extraction, concentration and purification. Here, we evaluate a range of methods to separate viral particles from stream biofilms, and to concentrate and purify them prior to DNA extraction and metagenome sequencing. Based on epifluorescence microscopy counts of viral-like particles (VLP) and DNA yields, we optimize a protocol including treatment with tetrasodium pyrophosphate and ultra-sonication to disintegrate biofilms, tangential-flow filtration to extract and concentrate VLP, followed by ultracentrifugation in a sucrose density gradient to isolate VLP from the biofilm slurry. Viromes derived from biofilms sampled from three different streams were dominated by Siphoviridae, Myoviridae and Podoviridae and provide first insights into the viral diversity of stream biofilms. Our protocol optimization provides an important step towards a better understanding of the ecological role of viruses in stream biofilms.

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Hogan, J. Aaron, Rusty A. Feagin, Gregory Starr, Michael Ross, Teng-Chiu Lin, Christine O’connell, Thomas P. Huff, et al. "A Research Framework to Integrate Cross-Ecosystem Responses to Tropical Cyclones." BioScience 70, no. 6 (May 6, 2020): 477–89. http://dx.doi.org/10.1093/biosci/biaa034.

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Abstract Tropical cyclones play an increasingly important role in shaping ecosystems. Understanding and generalizing their responses is challenging because of meteorological variability among storms and its interaction with ecosystems. We present a research framework designed to compare tropical cyclone effects within and across ecosystems that: a) uses a disaggregating approach that measures the responses of individual ecosystem components, b) links the response of ecosystem components at fine temporal scales to meteorology and antecedent conditions, and c) examines responses of ecosystem using a resistance–resilience perspective by quantifying the magnitude of change and recovery time. We demonstrate the utility of the framework using three examples of ecosystem response: gross primary productivity, stream biogeochemical export, and organismal abundances. Finally, we present the case for a network of sentinel sites with consistent monitoring to measure and compare ecosystem responses to cyclones across the United States, which could help improve coastal ecosystem resilience.

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Suominen, Arho, Marko Seppänen, and Ozgur Dedehayir. "A bibliometric review on innovation systems and ecosystems: a research agenda." European Journal of Innovation Management 22, no. 2 (March 4, 2019): 335–60. http://dx.doi.org/10.1108/ejim-12-2017-0188.

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Purpose The ecosystem perspective on innovation and business has emerged as the secret sauce of innovative organizations. While its theoretical foundations are premised on innovation system literature, the broad adoption of the ecosystem concept has resulted in conceptual ambiguity. The purpose of this paper is to tackle the ambiguous use of innovation ecosystem terminology and structure a conceptual frame for the field, identifying definitions of an innovation ecosystem and how the concept has been established in previous literature. Design/methodology/approach This paper examines the ambiguous use of terminology by reviewing the literature with bibliometric coupling and co-citation analysis by which thematic differences in ecosystem literature were identified. The study gathered the scientific publications from Thomson Reuters Web of Sciences Core Collection (n=4,681) from 1990 to 2015. Findings Six major bibliometrically coupled clusters were identified, of which the three largest clusters are innovation system studies, regional innovation studies and technological innovation studies. In addition, further analysis shows an emerging cluster that is focused on ecosystems, having its roots in eight seminal papers. This ecosystem research cluster includes seven sub-clusters, such as innovation ecosystem studies, business ecosystem studies and studies focusing on ecosystem development. Research limitations/implications The authors’ approach highlights how a lot of recent ecosystem studies actually belong to previous, well-developed research streams. However, there is also a separate, emergent research stream that includes the innovation and ecosystem studies. As a research implication, the paper concludes by suggesting the research agenda for further studies. Originality/value Even though literature on innovation systems and ecosystems is extensive literature, no studies have captured the emergence of the ecosystems approach and its relation with the systems of innovation literature.

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Riley, Lesilie, Mark Dybdahl, and Robert Hall, Jr. "Grazing Effects of the New Zealand Mud Snail Across a Productivity Gradient in the Greater Yellowstone Ecosystem." UW National Parks Service Research Station Annual Reports 29 (January 1, 2005): 96–104. http://dx.doi.org/10.13001/uwnpsrc.2005.3623.

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Accurately predicting the effects of introduced species on native commumtles and ecosystems is a challenge. Utilizing methods of food web ecology, we measured grazing effects of the invasive freshwater New Zealand mud snail, Potamopyrgus antipodarum, in streams within the Greater Yellowstone Ecosystem. Previous results indicate that P. antipodarum can significantly reduce algal standing stocks in less than one week, but it is not yet known if grazing effects vary across streams differing in benthic algae production. In this study, we measured the strength of P. antipodarum grazing on algal resources across six streams varying widely in ambient primary production. In field enclosure experiments within each stream, we estimated direct grazing effects of snails on algae by measuring chlorophyll a, gross primary production and chlorophyll a-specific primary production. In most streams, P. antipodarum decreased overall algal standing stocks, as measured by chlorophyll a, even though gross primary production was not affected. As a result, chlorophyll-a specific primary production increased in productive streams. Finally, standardized comparisons of P. antipodarum-algae interactions indicated that grazing effects were largest in the most productive streams. The overall impact of P. antipodarum on native stream communities will be greatest in the most productive streams if these assemblages are also capable of supporting dense P. antipodarum populations.

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Hoover, Trent M., Xavier Pinto, and John S. Richardson. "Riparian canopy type, management history, and successional stage control fluxes of plant litter to streams." Canadian Journal of Forest Research 41, no. 7 (July 2011): 1394–404. http://dx.doi.org/10.1139/x11-067.

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The food webs of forest stream ecosystems are based primarily on cross-boundary flows of terrestrial plant litter (PL). As such, changes in the composition of riparian forest canopies can alter flows of PL, affecting the ecosystem functioning of adjacent streams. We measured seasonal changes in PL fluxes to 20 small streams flowing through temperate rain forests in southwestern British Columbia to determine how riparian forest type and riparian management history influence resource availability in these systems. Differences in PL fluxes among the four riparian forest types studied were most pronounced in the summer, when PL fluxes from clearcuts < riparian reserve strips and coniferous forests, and PL fluxes from deciduous-dominated forests < riparian reserve strips. PL fluxes also varied among seasons (spring < summer < autumn). Fluxes were similar in riparian reserve strips and coniferous forests of similar age, indicating that reserve strips maintain this crucial ecosystem process. Clearcutting of riparian forests dramatically increased light availability while reducing leaf litter inputs; these effects, however, lasted only a few years. As riparian forest stand age increased, inputs shifted from broadleaf to coniferous inputs, indicating a possible long-term decrease in the lability of the leaf litter resources available to stream consumers.

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Turunen, Jarno, Timo Muotka, and Jukka Aroviita. "Aquatic bryophytes play a key role in sediment-stressed boreal headwater streams." Hydrobiologia 847, no. 2 (November 14, 2019): 605–15. http://dx.doi.org/10.1007/s10750-019-04124-w.

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AbstractForestry-related land use can cause increasing instream sedimentation, burying and eradicating stream bryophytes, with severe ecological consequences. However, there is limited understanding of the relative roles and overall importance of the two frequently co-occurring stressors, increased fine sediments and loss of bryophytes, to stream biodiversity and ecosystem functions. By using random forest modeling and partial dependence functions, we studied the relative importance of stream bryophytes and fine sediments to multiple biological endpoints (leaf-decaying fungi, diatom, bryophyte, and benthic macroinvertebrate communities; leaf decomposition) using field survey data from headwater streams. Stream bryophyte abundance and richness were negatively related to fine sediment cover, highlighting the detrimental effect of sedimentation on bryophytes. However, bryophyte abundance was consistently more important a determinant of variation in community composition than was fine sediment cover. Leaf decomposition was influenced by shredder abundance, water temperature and, to a lesser degree, stream size. Our results suggest that the loss of stream bryophytes due to increasing sedimentation, rather than fine sediments per se, seems to be the key factor affecting multiple biological responses. Enhancing the re-establishment of bryophyte stands could partly compensate for the negative impacts of sedimentation on bryophytes and, consequently, on several other components of boreal stream ecosystems.

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Scrimgeour, Garry J., William M. Tonn, and Nicholas E. Jones. "Quantifying effective restoration: reassessing the productive capacity of a constructed stream 14 years after construction." Canadian Journal of Fisheries and Aquatic Sciences 71, no. 4 (April 2014): 589–601. http://dx.doi.org/10.1139/cjfas-2013-0354.

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Using natural streams as references against which ecosystem structure and function could be compared, we examined the short-term (1–3 years) and long-term (14 years) effectiveness of a 3.4 km constructed stream in the Northwest Territories, Canada. The constructed stream variously showed little to marked improvements 14 years after construction (2011), relative to 1998–2000 and to reference streams, depending on the stream attribute. Many attributes related to stocks of organic matter remained well below reference levels in the constructed stream after 14 years. Leaf matter processing rates increased in the constructed stream to the point of convergence with reference streams in 2011, but the latter still had superior leaf retention abilities. By Year 14, benthic invertebrate composition in the constructed stream showed some convergence with reference streams, although densities generally lagged, especially in riffles. In 2011, growth of young-of-the-year Arctic grayling (Thymallus arcticus) from the constructed stream was substantially greater relative to 1998–2001, but remained well below contemporary reference levels. Our mixed results raise questions about the definition and time scale of successful restoration.

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Sargac, Jasmina, Richard Johnson, Francis Burdon, Amélie Truchy, Geta Rîşnoveanu, Peter Goethals, and Brendan McKie. "Forested Riparian Buffers Change the Taxonomic and Functional Composition of Stream Invertebrate Communities in Agricultural Catchments." Water 13, no. 8 (April 9, 2021): 1028. http://dx.doi.org/10.3390/w13081028.

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Riparian zones form the interface between stream and terrestrial ecosystems and play a key role through their vegetation structure in determining stream biodiversity, ecosystem functioning and regulating human impacts, such as warming, nutrient enrichment and sedimentation. We assessed how differing riparian vegetation types influence the structural and functional composition (based on species traits) of stream invertebrate communities in agricultural catchments. We characterized riparian and stream habitat conditions and sampled stream invertebrate communities in 10 independent site pairs, each comprising one “unbuffered” reach lacking woody riparian vegetation and a second downstream reach with a woody riparian buffer. Forested riparian buffers were associated with greater shading, increased gravel content in stream substrates and faster flow velocities. We detected changes in invertebrate taxonomic composition in response to buffer presence, with an increase in sensitive Ephemeroptera, Plecoptera and Trichoptera (EPT) taxa and increases in key invertebrate species traits, including species with preference for gravel substrates and aerial active dispersal as adults. Riparian vegetation independently explained most variation in taxa composition, whereas riparian and instream habitat together explained most variation in functional composition. Our results highlight how changes in stream invertebrate trait distributions may indirectly reflect differences in riparian habitat, with implications for stream health and cross-ecosystem connectivity.

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Kasahara, Tamao, and Alan R. Hill. "Effects of rifflestep restoration on hyporheic zone chemistry in N-rich lowland streams." Canadian Journal of Fisheries and Aquatic Sciences 63, no. 1 (January 1, 2006): 120–33. http://dx.doi.org/10.1139/f05-199.

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Stream restoration projects that aim to rehabilitate ecosystem health have not considered surfacesubsurface linkages, although stream water and groundwater interaction has an important role in sustaining stream ecosystem functions. The present study examined the effect of constructed riffles and a step on hyporheic exchange flow and chemistry in restored reaches of several N-rich agricultural and urban streams in southern Ontario. Hydrometric data collected from a network of piezometers and conservative tracer releases indicated that the constructed riffles and steps were effective in inducing hyporheic exchange. However, despite the use of cobbles and boulders in the riffle construction, high stream dissolved oxygen (DO) concentrations were depleted rapidly with depth into the hyporheic zones. Differences between observed and predicted nitrate concentrations based on conservative ion concentration patterns indicated that these hyporheic zones were also nitrate sinks. Zones of low hydraulic conductivity and the occurrence of interstitial fines in the restored cobble-boulder layers suggest that siltation and clogging of the streambed may reduce the downwelling of oxygen- and nitrate-rich stream water. Increases in streambed DO levels and enhancement of habitat for hyporheic fauna that result from rifflestep construction projects may only be temporary in streams that receive increased sediment and nutrient inputs from urban areas and croplands.

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Esteves, Katharina Eichbaum, José Marcelo Rocha Aranha, and Míriam Pilz Albrecht. "ECOLOGIA TRÓFICA DE PEIXES DE RIACHO: UMA RELEITURA 20 ANOS DEPOIS." Oecologia Australis 25, no. 02 (June 16, 2021): 266–82. http://dx.doi.org/10.4257/oeco.2021.2502.04.

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The great extent and diversity of ecological conditions of stream ecosystems in Brazil are widely recognized. In the last two decades, studies on stream fishes have contributed to the knowledge about their trophic ecology. However, the large amount of available information is yet fragmented. This chapter presents the state of the art of studies about feeding and trophic ecology of stream fishes in Brazil, an essential topic to understand ecosystem functioning. The review presented here was based on searches on different databases (Scopus, Web of Science, ASFA and Scielo). Results included studies that used different methods and approaches to evaluate the diet of fish species and assemblages, their relationship with morphology and ontogenetic variation, resource partitioning, seasonal and spatial variations, and anthropic impacts on trophic interactions. Finally, knowledge gaps and perspectives for future studies on fish trophic ecology are pointed out, including responses to anthropic influences, theoretical aspects, and the use of underexplored approaches to the subject, which may aid to our understanding of tropical streams

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Dewson, Zoë S., Alexander B. W. James, and Russell G. Death. "STREAM ECOSYSTEM FUNCTIONING UNDER REDUCED FLOW CONDITIONS." Ecological Applications 17, no. 6 (September 2007): 1797–808. http://dx.doi.org/10.1890/06-1901.1.

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Holmes, Robert M., Jeremy B. Jones, Stuart G. Fisher, and Nancy B. Grimm. "Denitrification in a nitrogen-limited stream ecosystem." Biogeochemistry 33, no. 2 (May 1996): 125–46. http://dx.doi.org/10.1007/bf02181035.

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DeAngelis, D. L., P. J. Mulholland, J. W. Elwood, A. V. Palumbo, and A. D. Steinman. "Biogeochemical cycling constraints on stream ecosystem recovery." Environmental Management 14, no. 5 (September 1990): 685–97. http://dx.doi.org/10.1007/bf02394718.

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Pérez, Javier, Francisco Correa-Araneda, Naiara López-Rojo, Ana Basaguren, and Luz Boyero. "Extreme temperature events alter stream ecosystem functioning." Ecological Indicators 121 (February 2021): 106984. http://dx.doi.org/10.1016/j.ecolind.2020.106984.

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Menninger, Holly L., Margaret A. Palmer, Laura S. Craig, and David C. Richardson. "Periodical Cicada Detritus Impacts Stream Ecosystem Metabolism." Ecosystems 11, no. 8 (September 27, 2008): 1306–17. http://dx.doi.org/10.1007/s10021-008-9194-4.

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40

Hall, Jr., Robert, Jennifer Tank, and Mark Dybdahl. "Exotic Snails Dominate Nitrogen and Carbon Cycling in a Highly Productive Stream." UW National Parks Service Research Station Annual Reports 25 (January 1, 2001): 72–77. http://dx.doi.org/10.13001/uwnpsrc.2001.3457.

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Individual animal species can impact ecosystem processes, but few exotic animal species have demonstrated ecosystem-scale impacts, in spite of large population sizes. We combined wholeÂstream measures of carbon and nitrogen fluxes with rates of consumption and ammonium excretion to show that an exotic freshwater snail, Potamopyrgus antipodarum, dominated carbon and nitrogen fluxes in a highly productive stream. Exotic snails consumed 75% of gross primary productivity, and their excretion accounted for two-thirds of ammonium demand. These large fluxes were due to high snail biomass rather than high per-biomass rates of excretion or consumption. This exotic snail may dramatically alter ecosystem function in rivers, with potential consequences for food web structure and element transport. Individual animals species can alter ecosystem functioning, such as nutrient cycling and storage, by directly altering carbon or nitrogen flux through grazing or excretion of ammonium (Grimm 1988, Frank et al. 1997, Vanni 2002), or indirectly via predation (e.g. Schindler et al. 1997). Despite numerous examples linking animal species with ecosystem processes, e. g., nutrient fluxes, there have been only a few examples showing how exotic animals may affect ecosystem processes or overall functions (Strayer et al. 1999, Lovett et al. 2003). Exotic animals might provide a model system for examining single-species impacts on ecosystem processes for several reasons. There are potentially strong ecosystem-scale impacts from exotic animals because they sometimes can dominate invaded ecosystems in terms of biomass. They also might bring a new trait to the invaded ecosystem, e.g. a generalist predator. However, there are few generalizations about how an exotic animal will impact native ecosystems, in spite of many impact studies which are mostly at the population or community level (Parker et al. 1999, Byers et al. 2002). Parker et al. (1999) presented a framework for considering exotic species impact as: I = RxAxE, where R =range (unit area), A =biomass per unit area, and E = per-biomass impact. LocalÂscale impact can be determined by either high biomass (e.g. Strayer et al. 1990) or by high perÂbiomass impact relative to native species, which may include an exotic species that brings a novel trait (Vitousek 1990, Byers 2000). Despite this framework, we do not know the degree to which either high biomass or high per-biomass impact contributes to overall ecosystem-scale impact by invading animals. Separating these two will allow better prediction of impacts in that we can focus research and management on understanding either specific traits or potential maximum biomass of invaders. We studied the role of the exotic New Zealand mud snail, Potamopyrgus antipodarum, on carbon. (C) cmd nitrogen (N) fluxes in Polecat Creek, Wyoming (Fig. I). We scaled their per-biomass rates of orgcmic matter consumption and ammonium excretion by snails to whole-stream rates in an 800-m reach. We compared these scaled estimates with whole-stream measures of C-fixation and N cycling to estimate the snail's contribution to stream C and N cycling (Grimm 1988, Vanni 2002). Because we scaled the impact of snails by multiplying per-biomass rates by snail biomass, we were able to estimate the degree to which high biomass or high per-biomass rates contnouted to the dominance of N and C fluxes in this stream. We compared both the per biomass rates and dominance of ecosystem N fluxes by Potamopyrgus with literature values for other freshwater invertebrates.

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Jackson, Breeanne K., and S. Mažeika P. Sullivan. "Influence of wildfire severity on geomorphic features and riparian vegetation of forested streams of the Sierra Nevada, California, USA." International Journal of Wildland Fire 29, no. 7 (2020): 611. http://dx.doi.org/10.1071/wf19114.

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Fires are a common feature of many landscapes, with numerous and complex ecological consequences. In stream ecosystems, fire can strongly influence fluvial geomorphic characteristics and riparian vegetation, which are structural components of stream–riparian ecosystems that contribute to biodiversity and ecosystem function. However, the effects of fire severity on stream–riparian ecosystems in California’s Sierra Nevada region (USA) are not well described, yet critical for effectively informing fire management and policy. At 12 stream reaches paired by fire severity (one high-severity burned, one low-severity burned), no significant differences were found in riparian plant community cover and composition or stream geomorphic characteristics 2–15 years following wildfire. In addition, minimal changes in riparian vegetation and stream geomorphic properties were observed in the first summer following the extensive and severe Rim Fire. However, an upstream-to-downstream influence of multiple fire occurrences was observed over the previous 81 years within each catchment on stream geomorphic metrics, including sediment size, embeddedness and channel geometry, at our study reaches. The inconsistent effects of wildfire on stream–riparian vegetation and geomorphic characteristics over space and time may be related to time since fire and precipitation.

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Reinaldo Finkler, Nícolas, Flavia Tromboni, Iola Boëchat, Björn Gücker, and Davi Gasparini Fernandes Cunha. "Nitrogen and Phosphorus Uptake Dynamics in Tropical Cerrado Woodland Streams." Water 10, no. 8 (August 14, 2018): 1080. http://dx.doi.org/10.3390/w10081080.

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Pollution abatement through phosphorus and nitrogen retention is a key ecosystem service provided by streams. Human activities have been changing in-stream nutrient concentrations, thereby altering lotic ecosystem functioning, especially in developing countries. We estimated nutrient uptake metrics (ambient uptake length, areal uptake rate, and uptake velocity) for nitrate (NO3–N), ammonium (NH4–N), and soluble reactive phosphorus (SRP) in four tropical Cerrado headwater streams during 2017, through whole-stream nutrient addition experiments. According to multiple regression models, ambient SRP concentration was an important explanatory variable of nutrient uptake. Further, best models included ambient NO3–N and water velocity (for NO3–N uptake metrics), dissolved oxygen (DO) and canopy cover (for NH4–N); and DO, discharge, water velocity, and temperature (for SRP). The best kinetic models describing nutrient uptake were efficiency-loss (R2 from 0.47–0.88) and first-order models (R2 from 0.60–0.85). NO3–N, NH4–N, and SRP uptake in these streams seemed coupled as a result of complex interactions of biotic P limitation, abiotic P cycling processes, and the preferential uptake of NH4–N among N-forms. Global change effects on these tropical streams, such as temperature increase and nutrient enrichment due to urban and agricultural expansion, may have adverse and partially unpredictable impacts on whole-stream nutrient processing.

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Almaraz, Maya, and Stephen Porder. "Reviews and syntheses: measuring ecosystem nitrogen status – a comparison of proxies." Biogeosciences 13, no. 18 (September 28, 2016): 5395–403. http://dx.doi.org/10.5194/bg-13-5395-2016.

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Abstract. There are many proxies used to measure nitrogen (N) availability in watersheds, but the degree to which they do (or do not) correlate within a watershed has not been systematically addressed. We surveyed the literature for intact forest or grassland watersheds globally, in which several metrics of nitrogen availability have been measured. Our metrics included the following: foliar δ15N, soil δ15N, net nitrification, net N mineralization, and the ratio of dissolved inorganic to organic nitrogen (DIN : DON) in soil solution and streams. We were particularly interested in whether terrestrial and stream based proxies for N availability were correlated where they were measured in the same place. Not surprisingly, the strongest correlation (Kendall's τ) was between net nitrification and N mineralization (τ = 0.71, p < 0.0001). Net nitrification and N mineralization were each correlated with foliar and soil δ15N (p < 0.05). Foliar and soil δ15N were more tightly correlated in tropical sites (τ = 0.68, p < 0.0001), than in temperate sites (τ = 0.23, p = 0.02). The only significant correlations between terrestrial- and water-based metrics were those of net nitrification (τ = 0.48, p = 0.01) and N mineralization (τ = 0.69, p = 0.0001) with stream DIN : DON. The relationship between stream DIN : DON with both net nitrification and N mineralization was significant only in temperate, but not tropical regions. To our surprise, we did not find a significant correlation between soil δ15N and stream DIN : DON, despite the fact that both have been used to infer spatially or temporally integrated N status. Given that both soil δ15N and stream DIN : DON are used to infer long-term N status, their lack of correlation in watersheds merits further investigation.

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Mutinova, Petra Thea, Maria Kahlert, Benjamin Kupilas, Brendan G. McKie, Nikolai Friberg, and Francis J. Burdon. "Benthic Diatom Communities in Urban Streams and the Role of Riparian Buffers." Water 12, no. 10 (October 9, 2020): 2799. http://dx.doi.org/10.3390/w12102799.

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Urbanization impacts stream ecosystems globally through degraded water quality, altered hydrology, and landscape disturbances at the catchment and riparian scales, causing biodiversity losses and altered system functioning. Addressing the “urban stream syndrome” requires multiple mitigation tools, and rehabilitation of riparian vegetation may help improve stream ecological status and provide key ecosystem services. However, the extent to which forested riparian buffers can help support stream biodiversity in the face of numerous environmental contingencies remains uncertain. We assessed how a key indicator of stream ecological status, benthic diatoms, respond to riparian habitat conditions using 10 urban site pairs (each comprising of one unbuffered and one buffered reach), and additional urban downstream and forest reference upstream sites in the Oslo Fjord basin. Diatom communities were structured by multiple drivers including spatial location, land use, water quality, and instream habitat. Among these, riparian habitat condition independently explained 16% of variation in community composition among site pairs. Changes in community structure and indicator taxa, along with a reduction in pollution-tolerant diatoms, suggested tangible benefits of forested riparian buffers for stream biodiversity in urban environments. Managing urban impacts requires multiple solutions, with forested riparian zones providing a potential tool to help improve biodiversity and ecosystem services.

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Clarke, Amber, P. S. Lake, and Dennis J. O'Dowd. "Ecological impacts on aquatic macroinvertebrates following upland stream invasion by a ponded pasture grass (Glyceria maxima) in southern Australia." Marine and Freshwater Research 55, no. 7 (2004): 709. http://dx.doi.org/10.1071/mf04043.

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Glyceria maxima (Reed sweet-grass), an emergent aquatic grass native to Eurasia, has naturalised in North America, New Zealand and southern Australia. Introduced as a ponded pasture species, it threatens native biodiversity and ecosystem processes in freshwater wetlands and waterways. We compared paired sections, either invaded or not invaded by G. maxima, of three upland streams in Gippsland, Victoria, Australia to infer its impacts on macroinvertebrate abundance, morphospecies density, and morphospecies and functional feeding group (FFG) composition. Its potential effects in altering sedimentation were explored by comparing stream channel morphology in paired stream sections at one site. Invasion by G. maxima appears to drive changes in macroinvertebrate morphospecies composition and FFG composition, reducing a diverse array of macroinvertebrates to a more uniform fauna. The estimated volume of plant/sediment matrix in a 50 m invaded stream section was around 1100 m3, nearly 15-fold greater than in an adjacent uninvaded stream section. Glyceria maxima is an autogenic ecosystem engineer, with the ability to convert sections of fast-flowing aerobic streams into partially anaerobic swamps. By generating a root-mat swamp with a high capacity to process nutrients, G. maxima may facilitate its own growth and spread, as well as that of secondary invaders.

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Raitif, Julien, Manuel Plantegenest, and Jean-Marc Roussel. "From stream to land: Ecosystem services provided by stream insects to agriculture." Agriculture, Ecosystems & Environment 270-271 (February 2019): 32–40. http://dx.doi.org/10.1016/j.agee.2018.10.013.

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Whitfield, Paul H., and Norman L. Wade. "Transient water quality events in british Columbia coastal streams." Water Science and Technology 33, no. 2 (January 1, 1996): 151–61. http://dx.doi.org/10.2166/wst.1996.0045.

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Transient events are rarely observed because of their aperiodic nature and short time duration. Often, it is not practical to sample these events using traditional methods. Typically, electronic instruments are required to gather sufficient data to observe transient events in streams and rivers. In many cases, data loggers equipped with water quality sensors offer the only reasonable opportunity to study these events. Data gathered at high frequency from two small streams illustrate some features of transient water events. These events illustrate the variety of changes observed in streams during both natural and man-induced events. Transient events may result from impacts on the entire watershed or from direct inputs to the stream channel. How a watershed responds to an event may be characteristic of ecosystem response to the disturbance. Events which affect the entire watershed differ in mechanism between the two study watersheds. This is a result of the different nature of the two ecosystems. Direct stream effects are more common in the urbanized watershed, and have properties which are distinct from the events affecting the entire watershed. The response of the system to transient impacts provides insight into the processes within the ecosystems. Data from a two month period in 1995 is used to illustrate observation and analysis techniques.

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MacSween, Jessica, Shawn J. Leroux, and Ken D. Oakes. "Cross-ecosystem effects of a large terrestrial herbivore on stream ecosystem functioning." Oikos 128, no. 1 (September 24, 2018): 135–45. http://dx.doi.org/10.1111/oik.05331.

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Rivers, Erin, Sara McMillan, Colin Bell, and Sandra Clinton. "Effects of Urban Stormwater Control Measures on Denitrification in Receiving Streams." Water 10, no. 11 (November 5, 2018): 1582. http://dx.doi.org/10.3390/w10111582.

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Urban areas are increasingly adopting the use of ecologically-based technologies for stormwater management to mitigate the effects of impervious surface runoff on receiving water bodies. While stormwater control measures (SCMs) reduce runoff, their ability to influence ecosystem function in receiving streams is not well known. To understand the effect of SCMs on net ecosystem function in stream networks, we measured sediment denitrification in four streams across a gradient of urban and suburban residential development in Charlotte, NC. We evaluated the influence of SCM inputs on actual (DNF) and potential (DEA) denitrification activity in stream sediments at the SCM-stream confluence to quantify microbial processes and the environmental factors that control them. DNF was variable across sites, ranging from 0–6.60 mg-N·m−2·h−1 and highly correlated with in-stream nitrate (NO3-N) concentrations. Sites with a greater impervious area showed a pattern of significantly higher DEA rates upstream of the SCM compared to downstream, while sites with less imperviousness showed the opposite trend. We hypothesize that this is because of elevated concentrations of carbon and nitrogen provided by pond and wetland outflows, and stabilization of the benthic habitat by lower peak discharge. These results suggest that SCMs integrated into the watershed have the potential to create cascading positive effects on in-stream nutrient processing and thereby improve water quality; however, at higher levels of imperviousness, the capacity for SCMs to match the scale of the impacts of urbanization likely diminishes.

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Francis, Tessa B., Daniel E. Schindler, and Jonathan W. Moore. "Aquatic insects play a minor role in dispersing salmon-derived nutrients into riparian forests in southwestern Alaska." Canadian Journal of Fisheries and Aquatic Sciences 63, no. 11 (November 1, 2006): 2543–52. http://dx.doi.org/10.1139/f06-144.

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Recent research has highlighted the importance of nutrients derived from Pacific salmon (Oncorhynchus spp.) carcasses for coastal freshwater and riparian ecosystems. To investigate the role of emerging aquatic insects in dispersing salmon nutrients from spawning streams to riparian habitats, we quantified the emergence and return rates of mayflies (Ephemeroptera), stoneflies (Plecoptera), and caddisflies (Trichoptera) on Pick Creek in southwestern Alaska and, using stable isotopes, estimated the associated flux of nutrients derived from sockeye salmon (Oncorhynchus nerka) to streamside forests. Between June and September of 2004, 7.6 mg·m–2 of salmon-derived nitrogen emerged from Pick Creek in the form of aquatic invertebrates, 6.7 mg·m–2 of which was transferred to the terrestrial ecosystem. Dispersal patterns on four area streams showed that the majority of stream-borne nutrients are deposited within 25 m of the stream. Aquatic insects represent a minor vector for salmon nutrients to terrestrial systems, dispersing less than 0.03% of total nitrogen imported to Pick Creek by spawning salmon. Nevertheless, emerging insects make available salmon-derived resources otherwise inaccessible to some terrestrial consumers.

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Journal articles on the topic 'Stream ecosystem'

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