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Wetlands in Montane and Subalpine Subregions are increasingly recognized as important hydrologic features that support ecosystem function. However, it is currently not clear how climate trends will impact wetland hydrological processes (e.g., evaporative fluxes) across spatiotemporal scales. Therefore, identifying the factors that influence wetland hydrologic response to climate change is an important step in understanding the sensitivity of these ecosystems to environmental change. We used stable water isotopes of hydrogen and oxygen (δ2H and δ18O), coupled with climate data, to determine the spatiotemporal variability in isotopic signatures of wetland source waters and understand the influence of evaporative fluxes on wetlands in the Kananaskis Valley. Our results show that the primary runoff generation mechanism changes throughout the growing season resulting in considerable mixing in wetland surface waters. We found that evaporative fluxes increased with decreasing elevation and that isotopic values became further removed from meteoric water lines during the late peak- and into the post-growing seasons. These findings suggest that a change in the water balance in favor of enhanced evaporation (due to a warmer and longer summer season than present) will not only lead to greater water loss from the wetlands themselves but may also reduce the water inputs from their catchments.

It is becoming increasingly popular to reintroduce beaver to streams with the hopes of restoring riparian ecosystem function or reducing some of the hydrological impacts of climate change. One of the risks of relying on beaver to enhance ecosystem water storage is that their dams are reportedly more apt to fail during floods which can exacerbate flood severity. Missing are observations of beaver dam persistence and water storage capacity during floods, information needed to evaluate the risk of relying on beaver as a nature‐based flood solution. A June rainstorm in 2013 triggered the largest recorded flood in the Canadian Rocky Mountains west of Calgary, Alberta. We opportunistically recorded hydrometric data during the rainfall event at a beaver‐occupied peatland that has been studied for more than a decade. We supplemented these observations with a post‐event regional analysis of beaver dam persistence. Results do not support two long‐held hypotheses—that beaver ponds have limited flood attenuation capacity and commonly fail during large flood events. Instead we found that 68% of the beaver dam cascade systems across the region were intact or partially intact after the event. Pond fullness, in addition to the magnitude of the water‐sediment surge, emerged as important factors in determining the structural fate of dam cascade sequences. Beaver ponds at the instrumented site quickly filled in the first few hours of the rain event and levels were dynamic during the event. Water storage offered by the beaver ponds, even ones that failed, delayed downstream floodwater transmission. Study findings have important implications for reintroducing beaver as part of nature‐based restoration and climate change adaptation strategies.

Beavers are expanding into cities as they recolonize their historic range. While they increase the ecological functioning of urban green areas, human-beaver conflicts occur. Public support to deal with conflicts has shifted from population to forage control. Tree guards are becoming popular with management personnel in North America and Europe to reduce damage to valuable trees. The problem is that this management technique has not been studied. We inventoried the tree guard types in use in natural and manicured river parks in the City of Saskatoon, Canada, determined their adherence to an installation protocol by measuring guard dimensions, and assessed the relative effectiveness of guards in protecting trees from beaver cutting. The inventory revealed that four types of tree guards are in use, ranging from light gauge chicken wire to heavy gauge chain link fencing. Overall, 11% of the trees with guards that we inventoried were cut by beavers, but variation among guard types was observed. Less than 10% of trees with type i and ii guards were beaver cut whereas 17% of trees with types iii and iv guards were beaver cut. Fewer trees were cut when there was adherence to installation protocol, regardless of guard type. Cut trees with guard types i, iii and iv experienced both minor and major damage whereas cut trees with guard type ii experienced only minor damage. The study results have implications for developing effectiveness and implementation monitoring plans for tree guards as part of an overall beaver management plan.

Mountain fens are limited in their spatial extent but are vital ecosystems for biodiversity, habitat, and carbon and water cycling. Studies of fen hydrological function in northern regions indicate the timing and magnitude of runoff is variable, with atmospheric and environmental conditions playing key roles in runoff production. How the complex ecohydrological processes of mountain fens that govern water storage and release as well as peat accumulation will respond to a warmer and less snowy future climate is unclear. To provide insight, we studied the hydrological processes and function of Sibbald fen, located at the low end of the known elevation range in the Canadian Rocky Mountains, over a dry period. We added an evapotranspiration function to the Spence hydrological function method to better account for storage loss. When frozen in spring and early summer, the fen primarily transmits water. When thawed, the fen's hydrological function switches from water transmission to water release, leading to a summertime water table decline of nearly 1 m. Rainfall events larger than 5 mm can transiently switch fen hydrological function to storage, followed by contribution, depending on antecedent conditions. The evapotranspiration function was dominant only for a brief period in late June and early July when rainfall was low and the ground was still partially frozen, even though evapotranspiration accounted for the largest loss of storage from the system. This research highlights the mechanisms by which mountain peatlands supply baseflow during drought conditions, and the importance of frozen ground and rainfall in regulating their hydrological function. The study has important implications for the sustainability of low elevation mountain fens under climate change.

Beavers profoundly alter streams by building dams. Beaver dams change how water, sediment, nutrients and energy flow through stream corridors enhancing both habitat diversity and landscape connectivity. Humans are captivated by learning from nature and trying to mimic it, especially in human-degraded environments. There is considerable eagerness for using beaver dam analogues (BDAs), also called simulated beaver structures, as low-tech, low cost solutions for restoring the functioning of degraded streams where beavers are not present and cannot survive. The use of BDAs in stream enhancement projects, especially in the western United States, is outpacing the research, leading to questions about whether BDAs do, in fact, yield similar ecosystem-scale effects as natural beaver dams. We review the different names used for BDAs, discuss the many ways these structures can be built and how different types function, and how they compare to real beaver dams. We conclude the talk by exploring what we can expect from various types of BDAs in the short and long term and whether these structures can lead to stream and riparian zone restoration that can facilitate the return of beavers.

Mountain lakes are distinctive water bodies that not only serve as a crucial water resource for the inhabitants of the upland regions but also as an important destination for millions of tourists who are attracted by their beauty. Mountain lakes are fragile water bodies that are experiencing changes in their hydrological processes owing to global warming. Understanding the consequences is important as it can help identify whether climate change causes degradations in lake hydrological functioning. The interactions of hydrological processes in mountain lakes with external drivers are usually hard to explain explicitly owing to their complexity. To deal with that problem, scholars develop conceptual frameworks. The focus was on the Canadian Rocky Mountains where 5155 lakes were identified using GIS. To identify factors influencing lake hydrological function and their sensitivity to changing climate, a literature review was undertaken. Identified in the literature review were 13 natural drivers that reflected climate change impacts to lake hydrological functioning and 38 additional sub-factors that characterize the drivers. Using these factors, a conceptual framework for mountain lake hydrological functioning was developed. The major limitation to thorough testing of the conceptual framework was a small number of observations for lakes in the research area. Nevertheless, the conceptual framework is flexible and should be tested across many mountainous regions worldwide. Overall, the conducted research stresses the problem of limited hydrological understanding of lakes in the Canadian Rockies and presents a useful framework of the complex interactions of natural drivers and intra-lake processes under rising temperatures.

Beaver (Castor canadensis and Castor fiber) are regarded widely as ecosystem engineers and the dams they create are well-known for their ability to drastically alter the hydrology of rivers. As a result, beaver are increasingly being included in green infrastructure practices to combat the effects of climate change and enhance ecosystem resilience. Both drought and flood mitigation capabilities have been observed in watersheds with beaver dam structures; however, how dams possess contrasting mitigation abilities is not fully understood since most studies neglect to acknowledge variation in beaver dam structures. In this study, an extensive cross-site survey of the physical and hydrologic properties of beaver dams was conducted in the Canadian Rocky Mountains in Alberta. This research aimed to improve the understanding of the hydrology of beaver dams by categorizing dams using their intrinsic properties and landscape settings to identify fundamental patterns that may be applicable across landscape types. The dam flow type classification from Woo and Waddington (1990) was evaluated in this new context and adapted to include two new flow types. The survey of intrinsic beaver dam properties revealed significant differences in dam structure across different sites. Physical differences in dam structure altered the dynamics and variance of pond storage and certain dam attributes related to the landscape setting. For instance, dam material influenced dam height and water source influenced dam length. However, a closer analysis of large rain events showed that the physical structure of dams alters seasonal dynamics of pond storage but not the response to rain events. Overall, this research shows that beaver dams can be both structurally and hydrologically very different from each other. Establishing broadly applicable classifications is vital to understanding the ecosystem resilience and mitigation services beaver dams provide.

Beavers have recolonized much of their historic range throughout the northern hemisphere and numerous studies have documented their habitat preferences and foraging behavior in rural riparian areas. Beavers, however, are also recolonizing waterways in cities, yet there has been little study of habitat use and foraging practices in these managed, urban systems. We studied beaver lodge distribution and riparian foraging preferences along the South Saskatchewan River, Canada, comparing a reach (24 km) passing through the City of Saskatoon where beavers and trees are managed with an upstream reach (29 km) passing through a conservation area where neither beavers nor trees are managed. In a canoe-based census at low flow, we found that beaver density in the conservation area was twice that in the city. Lodges were dispersed in the city with longer water-based distances between them. We found both differences and similarities in beaver foraging behavior. Riparian tree sampling along transects revealed that while diversity in the city and conservation area is markedly different, beavers preferentially cut green ash, Manitoba maple, paper birch and three poplars in both places. Beavers also cut six other tree species in the city, including three that are introduced, but the diversity was higher. A least-squares general linear model showed greater probability of cutting of trees further from the river in the city than conservation area, but of smaller diameter. Study results will be useful to urban planners in managing urban riparian forests and in developing beaver management plans.

Beaver are important agents of plant disturbance in wetland and riparian environments. They have two roles as a plant disturbance agent. They have earned the title of ecosystem engineers as one of their more remarkable aspects is their ability to alter physical ecosystem processes through building dam and canal networks. Beaver also are herbivores, capable of cutting woody vegetation at scales rivaled only by humans. This chapter includes information on beaver biology and ecology, the hydrologic and geomorphic changes incurred in wetlands and riparian systems by dam-building beavers, and how plants and plant communities respond to herbivory and habitat modifications made by beaver. Also described are beaver impacts to plant communities in wetlands and riparian areas disturbed by other agents. The chapter concludes by identifying pressing research questions.

Hyporheic exchange is important in increasing stream water transit time through basins and enhancing redox-sensitive biogeochemical reactions influencing downstream water quality. Such exchange may be enhanced by beaver dams which are common throughout low order streams including those originating in peatlands. To understand the influence of beaver dams on hyporheic flows and biogeochemical properties, nitrogen (N), dissolved organic nitrogen (DOC) and N cycling rates were observed along a beaver dammed, third-order stream draining Canadian Rocky Mountain peatland. Beaver dams enlarged the hyporheric zone from ≤1.5 to ≥7.5 m. The looping hyporheic flow path created a zone of N and DOC depletion adjacent to the dams. As a result, nitrification rates were lowest in this zone. Where hyporheic flows exited the riparian area and flowed back to the stream channel downstream of a dam, the adjacent riparian area served as a source of N and DOC to the stream. Enhanced nutrient influx to streams owing to beaver dam modified hyporheic flow paths has implications for stream biogeochemical cycling and ecological integrity, which need further exploration.

Major flood events are likely to happen more frequently and be more severe under changing land use and climatic conditions. Adapting to floods using resilience-based flood risk management (FRM) pol...

Ecosystem services valuation is not new, but few approaches have been developed to support ecosystem service consideration at the strategic level of futures-based planning. This paper demonstrates a practical, strategic environmental assessment approach to incorporate the valuation of ecosystem services in a futures-based assessment to support land use planning decisions for urban ecological areas. The application is based on the Northeast Swale, a valued natural area consisting of prairie grasslands and ephemeral wetlands in Saskatoon, Saskatchewan, Canada, which is subject to the cumulative pressures of urban development. Land use attributes or end points are adopted as proxies for ecosystem services to simplify the complexity of ecosystem services and to ensure outcomes that are practical and relevant to those who make land use decisions. The value of land use attributes is assessed using a choice experiment that incorporates visual interpretations of alternative land use futures, from which residents’ marginal willingness to pay for attributes are determined. Using compensating surplus values, tradeoffs between alternative future scenarios are explored and a range of preferred land use futures identified that depict different land use attributes and thus the suite of benefits residents derive from ecosystem services. Lessons are discussed for improved integration of ecosystem services valuation in strategic land use planning, and for translating complex ecosystem service concepts into practical directions for urban residents and for those responsible for land use policy and planning decisions.

Modeling nutrient transport during snowmelt in cold regions remains a major scientific challenge. A key limitation of existing nutrient models for application in cold regions is the inadequate representation of snowmelt, including hydrological and biogeochemical processes. This brief period can account for more than 80% of the total annual surface runoff in the Canadian Prairies and Northern Canada and processes such as atmospheric deposition, over-winter redistribution of snow, ion exclusion from snow crystals, frozen soils, and snowcovered area depletion during melt influence the distribution and release of snow and soil nutrients, thus affecting the timing and magnitude of snowmelt runoff nutrient concentrations. Research in cold regions suggests that nitrate (NO3) runoff at the field scale can be divided into five phases during snowmelt. In the first phase, water and ions originating from ion-rich snow layers travel and diffuse through the snowpack. This process causes ion concentrations in runoff to gradually increase. The second phase occurs when this snow ion meltwater front has reached the bottom of the snowpack and forms runoff to the edge-of-the-field (EOF). During the third and fourth phases, the main source of NO3 transitions from the snowpack to the soil. Finally, the fifth and last phase occurs when the snow has completely melted, and the thawing soil becomes the main source of NO3 to the stream. In this research, a process-based model was developed to simulate hourly export based on this five-phase approach. Results from an application in the Red River Basin of southern Manitoba, Canada shows that the model can adequately capture the dynamics and rapid changes of NO3 concentrations during this period at relevant temporal resolutions. This is a significant achievement to advance the current nutrient modeling paradigm in cold climates, which is generally limited to satisfactory results at monthly or annual resolutions. The approach can inform catchment-scale nutrient models to improve simulation of this critical snowmelt period. Nutrient exports Winter Snow Nitrate Agriculture Nutrient model

The environmental management literature suggests that resilience is key to managing complex systems and reducing vulnerability resulting from uncertainty and unexpected change. Yet, flood risk management (FRM) has emerged largely from a culture of resistance. This paper takes the pulse of the current state of FRM research, with a focus on how the scholarly community has approached governance for flood resilience. Our analysis of the FRM journal literature identified 258 articles addressing governance and flooding, resilience and adaptation. Five main research themes emerged from these articles, addressing a variety of issues, but mostly lacking the degree of integration needed to address the social-ecological complexity of FRM. Overall, research supporting the governance of FRM for resilience lacks integration, and methods of mitigating this lack of integration are poorly studied. We conclude with a discussion about the nature and scope of FRM research for resilience, and identify opportunities for more integrative FRM research that is more tightly coupled with policy and practice.

Beavers ingeniously alter environments to suit their needs of predator protection and food access, creating widespread effects on surface waters throughout their range. Beaver are thus considered the quintessential ecosystem engineer. They “engineer” landscapes largely by building dams across low-order streams to retain water. Dam building changes a wide range of ecological, hydrologic, and geomorphic processes that transform rivers into complex wetland systems capable of supporting a diversity of aquatic and terrestrial species. Although less studied, beavers live in and can significantly impact landscape processes in large rivers, wetlands, and lakes and unexpected places like landslides, brackish deltas, and glacial discharge environments. The earliest works on beaver are from a time when beaver were very much still being trapped to supply the fashion market in Europe with pelts (c. late 1800s to early 1900s). Works from this period primarily document the natural history of beaver. Research interest in beaver waned for several decades, coincident with low beaver populations. In the 1980s and 1990s, however, researcher interest in beaver was again piqued, which led to a little over a decade of studies documenting a range of ecosystem effects of beaver. Research on beaver ecosystem engineering was reinvigorated again in the mid- to late-2000s, coincident with rewilding efforts in Europe, beaver use in stream restoration activities in the United States, and rapid spread of the exotic, invasive beaver population in Tierra del Fuego. This encyclopedia entry provides a summary of the hydrogeomorphic processes known to be beaver-mediated, as well as the state of knowledge of how beaver form stream valleys and shape wetland ecosystems. Included are brief annotations of key literature. Ecological and biogeochemical impacts of beaver ponds are extensive, but a full description of them are beyond the scope of this annotated bibliography. The topic could benefit from greater synergistic and integrative research among biologists, geomorphologists, ecologists, and hydrologists.

If the aim of flood risk management (FRM) is to increase society’s resilience to floods, then a holistic treatment of flood risk is required that addresses flood prevention, defence, mitigation, preparation, and response and recovery. Progressing resilience-based management to flood risk requires both diversity and coordination of policy across multiple jurisdictions. Decision makers and the types of FRM policy decisions they make play a key role in implementing FRM policies and strategies that progress flood resilience. This paper explores how policy preferences held by FRM decision makers relate to the characteristics of resilient FRM policy. The research was conducted in three flood-prone provinces in western Canada using a multi-criteria analytical approach. The results show that while decision maker FRM priorities are similar across the Canadian Prairies, their preferred FRM policies differ. Further, preferred FRM policies were largely resistance-based and influenced at least as much by flood experiences and perceptions of flood risk as by more obvious administrative pressures such as cost, public acceptability, and environmental protection. Several observations emerge from these results for advancing a coordinated, diversified approach to FRM which is required for resilience, both for western Canada and for FRM more broadly.

Beaver dam analogues (BDAs) are becoming an increasingly popular stream restoration technique. One ecological function BDAs might help restore is suitable habitat conditions for fish in streams where loss of beaver dams and channel incision has led to their decline. A critical physical characteristic for fish is stream temperature. We examined the thermal regime of a spring-fed Canadian Rocky Mountain stream in relation to different numbers of BDAs installed in series over three study periods (April–October, 2017–2019). While all BDA configurations significantly influenced stream and pond temperatures, single- and double-configuration BDAs incrementally increased stream temperatures. Single and double configuration BDAs warmed the downstream waters of mean maxima of 9.9, 9.3 °C by respective mean maxima of 0.9 and 1.0 °C. Higher pond and stream temperatures occurred when ponding and discharge decreased, and vice versa. In 2019, variation in stream temperature below double-configuration BDAs was lower than the single-configuration BDA. The triple-configuration BDA, in contrast, cooled the stream, although the mean maximum stream temperature was the highest below these structures. Ponding upstream of BDAs increased discharge and resulted in cooling of the stream. Rainfall events sharply and transiently reduced stream temperatures, leading to a three-way interaction between BDA configuration, rainfall and stream discharge as factors co-influencing the stream temperature regime. Our results have implications for optimal growth of regionally important and threatened bull and cutthroat trout fish species.

Beaver ponds are surface-water features that are transient through space and time. Such qualities complicate the inclusion of beaver ponds in local and regional water balances, and in hydrological models, as reliable estimates of surface-water storage are difficult to acquire without time- and labour-intensive topographic surveys. A simpler approach to overcome this challenge is needed, given the abundance of the beaver ponds in North America, Eurasia, and southern South America. We investigated whether simple morphometric characteristics derived from readily available aerial imagery or quickly measured field attributes of beaver ponds can be used to approximate surface-water storage among the range of environmental settings in which beaver ponds are found. Studied were a total of 40 beaver ponds from four different sites in North and South America. The simplified volume–area–depth (V–A–h) approach, originally developed for prairie potholes, was tested. With only two measurements of pond depth and corresponding surface area, this method estimated surface-water storage in beaver ponds within 5 % on average. Beaver pond morphometry was characterized by a median basin coefficient of 0.91, and dam length and pond surface area were strongly correlated with beaver pond storage capacity, regardless of geographic setting. These attributes provide a means for coarsely estimating surface-water storage capacity in beaver ponds. Overall, this research demonstrates that reliable estimates of surface-water storage in beaver ponds only requires simple measurements derived from aerial imagery and/or brief visits to the field. Future research efforts should be directed at incorporating these simple methods into both broader beaver-related tools and catchment-scale hydrological models.

The North American beaver (Castor canadensis) is an invasive species in southern Patagonia, introduced in 1946 as part of a program by the Argentine government to augment furbearers. Research focus has turned from inventorying the beaver's population and ecosystem impacts toward eradicating it from the region and restoring degraded areas. Successful restoration, however, requires a fuller determination of how beavers have altered physical landscape characteristics, and of what landscape features and biota need to be restored. Our goal was to identify changes to the physical landscape by invasive beaver. We analyzed channel and valley morphology in detail at one site in each of the three major forest zones occurring on the Argentine side of Tierra del Fuego's main island. We also assessed 48 additional sites across the three forest biomes on the island to identify a broader range of aquatic habitat occupied and modified by beaver. Beaver build dams with Nothofagus tree branches on streams, which triggered mineral sediment accretion processes in the riparian zone, but not in ways consistent with the beaver meadow theory and only at a few sites. At the majority of sites, beavers actively excavated peat and mineral sediment, moved thousands of cubic meters of sediment within their occupied landscapes and used it to build dams. Beaver were also common in fen ecosystems where pond formation inundated and drowned peat forming mosses and sedges, and triggered a massive invasion of exotic plant species. Results highlight that restoration of fen ecosystems is a previously unrecognized but pressing and challenging restoration need in addition to reforestation of Nothofagus riparian forests. We recommend that decision-makers include the full ecosystem diversity of the Fuegian landscape in their beaver eradiation and ecosystem restoration plans.

Carbon (C) dynamics in northern peatlands are an important factor in the global C balance under climate change scenarios. They are microbially driven and influenced by the chemical composition of organic matter. Peatlands in the Rocky Mountains are usually formed on mineral sediments or developed with interbedded mineral lenses, which have been found to affect soil properties such as volumetric water content, pH, TOC and TN. Our objective was to investigate whether the presence and relative depth of mineral horizons (i.e., stratified mineral horizons) affect microbial community structure and C composition, and in turn influence C mineralization. Three organic soil profile types were selected in the Sibbald research wetland of southwestern Alberta: peat over silty mineral over calcareous sediment (PMC), peat over silty mineral over peat (PMP), and sedge peat over moss peat profiles (PP). Peat samples were subjected to C composition and microbial community abundance and structure measurement and then incubated to test potential C mineralization. The main differences were detected in subsurface peat. In subsurface peat above mineral sediments (PMC, PMP) versus at equivalent depth in PP, the presence of a mineral horizon caused different C mineralization (mg C-CO2 kg−1 soil) among soil types (PP > PMC and PMP). In addition, specific C mineralization (mg C-CO2 kg−1 SOC) decreased with depth in subsurface peat in PP, but not in PMP, as greater volumetric water content (θv) above the mineral horizon created anaerobic conditions in PMP. Microbial community structures also differed between PMP and PP due to different θv in peat below mineral sediments. Recalcitrant C: labile C, bacteria: fungi, and microbial physiological stress were greatest in the subsurface peat above mineral sediments. Depth had an even greater effect: both C mineralization and microbial abundance decreased significantly with depth. Moreover, microbial community structure mainly grouped according to relative depth. Overall, our findings indicated that stratified mineral horizons affected C mineralization, microbial community structure, and peat chemistry in subsurface peat.

Microform is important in understanding wetland functions and processes. But collecting imagery of and mapping the physical structure of peatlands is often expensive and requires specialized equipment. We assessed the utility of coupling computer vision-based structure from motion with multiview stereo photogrammetry (SfM-MVS) and ground-based photos to map peatland topography. The SfM-MVS technique was tested on an alpine peatland in Banff National Park, Canada, and guidance was provided on minimizing errors. We found that coupling SfM-MVS with ground-based photos taken with a point and shoot camera is a viable and competitive technique for generating ultrahigh-resolution elevations (i.e.

Soil profiles in mountain peatlands commonly show complex stratigraphy with both underlying and interbedded mineral sediments. The presence and types of mineral sediments may affect nutrient gradients via the vertical and horizontal movements of groundwater, which further influences biogeochemical processes, especially for deeper peat adjacent to mineral sediments. To study influences of stratified mineral sediments, we conducted this study in a mountain peatland with three different soil types: sedge peat/silty sediments/calcareous sediments (PMC), sedge peat/silty sediments/moss peat (PMP) and sedge peat/moss peat (PP). Our results indicate that spatial distributions of TOC, TN, pH and θv in this mountain peatland are regulated by mineral sediments. The influence of mineral sediments was more significant in deeper layers. Calcareous sediments strongly influenced spatial distribution of pH. Silty sediment layers influenced θv via slowing water infiltration into deeper layers. The pH and θv affected organic matter decomposition and thus TOC and TN distribution. At the same time, mineral sediments – especially the presence of calcareous sediments – also affected N cycling processes: net nitrification in PMC was higher than that in PP and PMP whereas net ammonification in PMC was lower. As expected, immobilization and nitrification decreased with depth. In addition, with depth, a lag phase for N cycling was found in deeper layers: immobilization and nitrification did not occur until after 7 days in middle peat or 28 days in deep peat in surface-like conditions. Moreover, the interaction of incubation time and soil types showed that the lag phase was different in different soil types. Overall, results suggest that interbedded mineral sediments in mountain peatlands can influence soil hydrology and pH, which in turn affect spatial distribution of soil properties and associated biogeochemical processes.

Marmot Creek Research Basin in the Canadian Rockies has been the site of intensive streamflow, groundwater, snow accumulation, precipitation, and air temperature observations at multiple elevations. The basin was instrumented in 1962, subjected to forestry experiments in the mid-1970s, and experienced extreme flooding in 2013. Climate change, forest cover change, and recent extreme weather make the basin an ideal laboratory for studying hydrological resilience. Observations show increases in low elevation air temperature, multiple day and spring precipitation, interannual variability of precipitation, and high elevation groundwater levels. Observations also show decreases in peak seasonal snow accumulation and low elevation groundwater levels. Despite these substantial hydrometeorological and groundwater changes, streamflow volume, timing of peak, and magnitude of the peak are not changing. Streamflow volumes are also insensitive to forest cover changes and teleconnections. The June 2013 flood was unprecedented in the period of record, and the basin significantly moderated the hydrological response to the extreme precipitation; the 2013 storm precipitation depth was 65% greater than the next highest storm total over 51 years; however, the 2013 peak streamflow was only 32% greater than the next highest peak flow recorded. The hydrology of Marmot Creek Research Basin displays remarkable resilience to changing climate, extreme weather, and forest cover change. Copyright © 2015 John Wiley & Sons, Ltd.

To illustrate the hydrological impact of climate and land use change on an unregulated basin, the agriculture- and wetland-dominated Smith Creek Research Basin (SCRB) was examined in detail. Streamflows (1975–1994) show behaviour typical of the Canadian Prairies – generation primarily by snowmelt and cessation in May due to lack of runoff or groundwater contributions. Depressional storage has been drained for decades, reducing the extent of ponds by 58% and increasing drainage channel length 780%. Climate has also changed; increasing temperatures since 1942 have brought on a gradual increase in the rainfall fraction of precipitation (no trends in total precipitation) and an earlier snowmelt by 2 weeks. The number of multiple-day rainfall events has increased by half, which may make rainfall-runoff generation mechanisms more efficient. Annual streamflow volume and runoff ratio have increased 14-fold and 12-fold, respectively, since 1975, with dramatically increasing contributions from rainfall and mixed runoff regimes. Snowmelt runoff has declined from 86% in the 1970s to 47% recently while rainfall runoff has increased from 7% to 34% of discharge. Peak discharge has tripled since 1975, with a major shift in 1994. Recent flood volumes in SCRB have been abnormally large, and high flows in June 2012 and flooding in June 2014 were caused solely by rainfall, something never before recorded at the basin. Changes to the observed character of precipitation, runoff generation mechanisms and depressional storage are substantial, but it is unlikely that any single change can explain the dramatic shift in SCRB surface hydrology. Further diagnostic investigation using process hydrology simulations is needed to explain the observed regime changes. Copyright © 2015 John Wiley & Sons, Ltd.

The Boreal Plains Ecozone (BPE) in Western Canada is expected to be an area of maximum ecological sensitivity in the 21st century. Successful climate adaptation and sustainable forest management require a better understanding of the interactions between hydrology, climate, and vegetation. This paper provides a perspective on the changing water cycle in the BPE from an interdisciplinary team of researchers, seeking to identify the critical knowledge gaps. Our review suggests the BPE will likely become drier and undergo more frequent disturbance and shifts in vegetation. The forest will contract to the north, though the southern boundary of the ecotone will remain in place. We expect detrimental impacts on carbon sequestration, water quality, wildlife, and water supplies. Ecosystem interactions are complex, and many processes are affected differently by warming and drying, thus the degree and direction of change is often uncertain. However, in the short term at least, human activities are the dominant source of change and are unpredictable but likely decisive. Current climate, hydrological, and ecological monitoring in the BPE are limited and inadequate to understand and predict the complex responses of the BPE to human activities and climate change. This paper provides a case study of how hydrological processes critically determine ecosystem functioning, and how our ability to predict system response is limited by our ability to predict changing hydrology. WIREs Water 2015, 2:505–521. doi: 10.1002/wat2.1098 For further resources related to this article, please visit the WIREs website.

Globally, greenhouse gas budgets are dominated by natural sources, and aquatic ecosystems are a prominent source of methane (CH(4)) to the atmosphere. Beaver (Castor canadensis and Castor fiber) populations have experienced human-driven change, and CH(4) emissions associated with their habitat remain uncertain. This study reports the effect of near extinction and recovery of beavers globally on aquatic CH4 emissions and habitat. Resurgence of native beaver populations and their introduction in other regions accounts for emission of 0.18-0.80 Tg CH(4) year(-1) (year 2000). This flux is approximately 200 times larger than emissions from the same systems (ponds and flowing waters that became ponds) circa 1900. Beaver population recovery was estimated to have led to the creation of 9500-42 000 km(2) of ponded water, and increased riparian interface length of >200 000 km. Continued range expansion and population growth in South America and Europe could further increase CH(4) emissions.

Mountain wetlands, although limited in their spatial extent, provide many important hydrological and ecological services. There is a need to know existing beaver habitation patterns across mountain wetlands because of emerging interest in using beaver to restore and protect riparian and wetland habitats. However, there exist few inventories of wetlands, or their use as beaver habitat, for any mountain region of North America. We studied the distribution of beaver-impacted mineral wetlands and peatlands in a 7,912 km2 area of the Canadian Rocky Mountains. Using aerial photography and an existing wetland database, we inventoried 529 wetlands at elevations of 1,215 to 2,194 m; peat soils were found at 69 % of the 81 field verified wetlands. Wetland distribution and beaver habitation varied by physiography and jurisdiction. While 75 % of the wetlands identified were located in the foothills region, beaver were twice as likely to inhabit those in the mountain region owing to differences in land use activities and wildlife conservation measures. Wetlands inhabited by beaver had an order of magnitude greater area of open water and 12 times the number of individual open water features than those without. Beaver-enhanced open water extent has far-reaching consequences for wetland ecohydrological and biogeochemical functioning.

Wetland habitat continues to be lost to cumulative effects of development on the landscape. Part of the problem is that there currently exists only limited guidance as to how to use the existing scientific tools, conceptual frameworks and guidance documents to advance cumulative effects assessment (CEA) from the project scale to the broader regional scale at which land-use planning occurs. To strengthen CEA science for wetlands there are three minimum requirements: (1) understand the baseline science of wetland functions; (2) delineate the primary drivers (anthropogenic and natural) of disturbance; and (3) develop the science to link drivers to changes in wetland function in an interactive, synergistic and cumulative way. The paper concludes by identifying ways in which the state of CEA science and management of wetlands could be improved.

Beaver ponds are surface water features that are transient through space and time. Such qualities complicate the inclusion of beaver ponds in local and regional water balances, and in hydrological models, as reliable estimates of surface water storage are difficult to acquire without time and labour intensive topographic surveys. A simpler approach to overcome this challenge is needed, given the abundance of the beaver ponds in North America, Eurasia and southern South America. We investigated whether simple morphometric characteristics derived from readily available aerial imagery or quickly measured field attributes of beaver ponds can be used to approximate surface water storage among the range of environmental settings in which beaver ponds are found. Studied were a total of 40 beaver ponds from four different sites in North and South America. The Simplified V-A-h approach, originally developed for prairie potholes, was tested. With only two measurements of pond depth and corresponding surface area, this method estimated surface water storage in beaver ponds within 5 % on average. Beaver pond morphometry was characterized by a median basin coefficient of 0.91, and dam length and pond surface area were strongly correlated with beaver pond storage capacity, regardless of geographic setting. These attributes provide a means for coarsely estimating surface water storage capacity in beaver ponds. Overall, this research demonstrates that reliable estimates of surface water storage in beaver ponds only requires simple measurements derived from aerial imagery and/or brief visits to the field. Future research efforts should be directed at incorporating these simple methods into both broader beaver-related tools and catchment scale hydrological models.

Increased land use intensity has been shown to adversely affect aquatic ecosystems. Multiple landscape stressors interact over space and time, producing cumulative effects. Cumulative Effects Assessment (CEA) is the process of evaluating the impact a development project may have on the ecological surroundings, but several challenges exist that make current approaches to cumulative effects assessment ineffective. The main objective of this study was to compare results of different methods used to link landscape stressors with stream responses in a highly developed watershed, where past work has shown that the river has experienced significant water quality and quantity changes to improve approaches to CEA. The study site was the lower reaches of the Athabasca River, Canada that have been subjected to a diverse range of intense anthropogenic developments since the late 1960s. Linkages between landscape change and river response were evaluated using correlation analyses, stepwise, multiple regression, and regression trees. Notable landscape changes include increased industrial development and forest cut-blocks, made evident from satellite imagery and supporting ancillary data sets. Simple regression analyses showed water use was closely associated with total phosphorus (TP) and Na+ concentrations, as well as specific conductance. The regression trees for total organic carbon (TOC), TP, and Na+ showed that the landscape variables that appear as the first characteristic were the same variables that showed significant relations for their respective simple regression models. Simple, stepwise, and multiple regressions in conjunction with regression trees were useful in this study for capturing the strongest associations between landscape stressors and river response variables. The results highlight the need for improved scaling methods and monitoring strategies crucial to managing cumulative effects to river systems. Integr Environ Assess Manag 2013;9:392–404. © 2012 SETAC

Intensification of agriculture has led to renewed efforts to drain wetlands throughout North American prairies. It is perceived to threaten downstream ecosystem health through enhancing nutrient, bacteria and salt loading. An experiment was conducted to determine temporal variations in wetland solute storage and export upon drainage. Water quality along seven ditches and five natural spills that form between wetlands was also compared. The experimental wetland acted as a solute storage zone prior to its drainage. Variations in salts and DOC were influenced by hydrological processes, whereas variations in nutrients and bacteria were also influenced by biotic and/or sorption processes. Wetland water quality was an important control of drainage water quality as the wetland ditch acted as a simple conduit. Concentrations of TDN, DOC, HCO3−, K+, and Ca2+ were higher in ditches than spills. Minimal changes in water quality along ditches and spills occurred, likely due to low spring temperatures that can restrict biotic processing and sorption. Since ditches connect wetlands to streams, they have a greater potential to contribute to downstream solute loading than spills. Wetland drainage efficiency and wetland water quality were deemed the factors critical to determining solute exports via ditches.

The cold regions hydrological model (CRHM) platform, a physically based hydrological model using a modular and object-oriented structure, has been applied for simulating the redistribution of snow by wind, snowmelt, infiltration, evapo-transpiration, soil moisture balance, surface depression storage and run-off routing. Land use and land cover classification is a preprocessing procedure to provide the required parameters for CRHM. Per-pixel-based and object-oriented classifications are the two major classification approaches currently in practice. The objective of this study is to evaluate whether the more complex object-oriented classification method can significantly improve the performance of the CRHM model in a prairie landscape. The study was conducted in the Smith Creek watershed in eastern Saskatchewan. Two Satellite Pour l'Observation de la Terre (SPOT) multispectral images were used to classify the area into seven classes: cropland, fallow, grassland, wetland, water, woodland and town/road. Both ...

Fast-paced watershed change, driven by anthropogenic development, is threatening the sustainability of freshwater resources across the globe. Developments within watersheds interact in a manner that is additive and synergistic over space and time. Such cumulative environmental effects are defined as the results of actions that are individually minor but collectively significant when added to other past, present, and reasonably foreseeable future actions. Cumulative effects assessment (CEA) then is broadly defined as the process of evaluating the potential impacts of such collective actions on the environment and is a requirement in many countries, including in Canada at the federal level under the Canadian Environmental Assessment Act. However, current approaches to CEA for river systems are proving to be ineffective, which is largely attributed to the disconnect between CEA science and practice. We highlight this gap herein by discussing contradictions in the CEA literature, challenges in quantifying cumulative interactions, including overcoming spatiotemporal scale issues, multiple hydrologic and ecological pathways, and lack of predictive analysis. Our analysis shows there is a need for improved CEA for river systems, and in responding to this need we propose a conceptual framework for better integrating science and practice for improved CEA for river systems using one of the most adversely affected rivers basins in Canada, the Athabasca River, as our model. We conclude by addressing the challenges inherent to CEA with the intent of providing scientists with ways to help improve CEA of river systems.

We examined how beaver dams affect key ecosystem processes, including pattern and process of sediment deposition, the composition and spatial pattern of vegetation, and nutrient loading and processing. We provide new evidence for the formation of heterogeneous beaver meadows on riverine system floodplains and terraces where dynamic flows are capable of breaching in-channel beaver dams. Our data show a 1.7-m high beaver dam triggered overbank flooding that drowned vegetation in areas deeply flooded, deposited nutrient-rich sediment in a spatially heterogeneous pattern on the floodplain and terrace, and scoured soils in other areas. The site quickly de-watered following the dam breach by high stream flows, protecting the deposited sediment from future re-mobilization by overbank floods. Bare sediment either exposed by scouring or deposited by the beaver flood was quickly colonized by a spatially heterogeneous plant community, forming a beaver meadow. Many willow and some aspen seedlings established in the more heavily disturbed areas, suggesting the site may succeed to a willow carr plant community suitable for future beaver re-occupation. We expand existing theory beyond the beaver pond to include terraces within valleys. This more fully explains how beavers can help drive the formation of alluvial valleys and their complex vegetation patterns as was first postulated by Ruedemann and Schoonmaker in 1938. Copyright © 2010 John Wiley & Sons, Ltd.

Investigation into the effects of beaver dams on hyporheic fluxes in channelled peatlands is needed to better understand how biological processes drive stream-riparian area connections and thus nutrient export, and to improve our overall conceptual model of water storage and flow through peatlands. The objective of this study was to determine the influence of beaver dams on vertical and lateral hyporheic exchange. Hydrometric methods were used to determine subsurface flow pathways and estimate hyporheic water fluxes for a third-order stream draining a Canadian Rocky Mountain peatland in 2006 and 2007. Three sites were studied – two contained small, in-channel beaver dams and the third was a control. Vertical hyporheic fluxes equaled or exceeded lateral hyporheic fluxes despite the fact that hydraulic conductivity of the stream bed tended to be lower than the banks, suggesting peat hydraulic properties were not the dominant factor in the development of hyporheic exchange in stream systems draining peatland...

We investigate herein the hypothesis that there is a significant relationship between bed particle mobility and benthic invertebrate abundance in the gravel-bed channel of the upper Colorado River in Rocky Mountain National Park. A large diversion channel called the Grand Ditch normally diverts a significant portion (∼50%) of the annual snowmelt runoff from the watershed northward out of the basin. In May 2003, a ∼30-m section of the ditch was breached, contributing substantially to the magnitude and duration of discharge in the Colorado River until the ditch breach was repaired in July of that year. As a result, all grain sizes in the river channel were mobilized, which contrasted sharply with the minimal gravel transport experienced during the exceptional drought of the previous year. Benthic macroinvertebrates were collected in the field using a Surber sampler at the same six locations for both years, and the number of individuals of the orders ephemeroptera (mayflies), plecoptera (stoneflies), trichoptera (caddisflies) and diptera (e.g. chironomids) was counted in the laboratory. The total number of individuals was 240% higher in 2003, and the proportion of mayflies in the samples increased from 25% in 2002 to 40% in 2003. In 2003, samples were also taken immediately upstream and downstream of a large flow obstruction in the channel in order to further isolate the relative importance of sediment transport against other variables affecting the stream habitat. Numbers of individuals for all taxa collected (particularly ephemeroptera and plecoptera) were nearly an order of magnitude higher at the upstream site than at the downstream, protected location. These results have important implications for the ecosystem management of streams within Rocky Mountain National Park and elsewhere. Copyright © 2008 John Wiley & Sons, Ltd.

The heterogeneous Boreal Shield forest in Canada is one of the most extensive pristine forests remaining in the world and is being intensely harvested. We studied the spatial variability of organic and inorganic N cycling processes in three Boreal Shield catchments in northwestern Ontario for 2 years before and 1 year following clearcutting. Net N mineralization rates were similar among upland conifer, upland deciduous and peatland stands, ranging from negligible to 150 mg kg−1 in the forest floor/peat soils and −30 to 40 mg kg−1 in mineral soils of the upland stands over the growing season. Net nitrification rates were generally negative

Slope wetlands generally occur at breaks in slope where discharging ground water maintains moist soil conditions. They often are found on the perimeter of highly permeable alluvial fans, but there have been no detailed hydrologic studies of these particular wetlands. We combined stream and spring flow measurements with five years of water-level and piezometric data to understand the hydrology of a 1.6 ha slope wetland at the base of a 5.2 ha alluvial fan in the central Rocky Mountains of Colorado. Step changes in streamflow inputs resulting from an upstream water diversion helped confirm the linkages inferred from the hydrometric data. Nearly 30% of the streamflow along a 180-m reach on the alluvial fan was lost to seepage. Discharge from two springs at the toe of the alluvial fan was eliminated and the piezometric head in the toe of the fan decreased by more than 80 cm within 1-2 days after the stream was diverted, indicating that stream seepage is the primary source of ground-water recharge for the alluvial fan. Streamflow and ground water discharging at the base of the alluvial fan were the primary wetland inflows, with summer precipitation playing a relatively minor role. Consequently, wetland water levels declined by up to 75 cm after the diversion began operating. The largest declines were in the lower part of the wetland, where surface sheet flow from the stream was the main water source. Continuing ground-water discharge into the upper part of the wetland limited the water level declines to less than 40 cm. The importance of streamflow as a water source distinguishes slope wetlands adjacent to alluvial fans from those found in other settings and makes them particularly vulnerable to upstream water diversions.

Gross and net nitrogen (N) ammonification and nitrification were measured in soils from an uncut and recently cut upland and peatland conifer stand in northwestern Ontario, Canada. Rates of gross total inorganic N immobilization were similar to gross mineralization, resulting in low net mineralization rates in soils from all four upland and peatland conifer stands. Gross ammonification rates were variable but similar in soils from uncut and cut peatland hollows (18–19 mg N kg−1 day−1) and upland forest floor soils (14–19 mg N kg−1 day−1). Gross ammonium ( $${\text{NH}}_{\text{4}}^ + $$ ) immobilization rates were also variable but similar to ammonification rates. Median gross nitrification rates were within 0–2 mg N kg−1 day−1 in soils from all four upland and peatland cut and uncut stands, although rates were consistently higher for the soils from the cut stands. Large variability in gross nitrification rates were observed in peatland soils, however the highest gross nitrification rates were measured in saturated peatland soils. Net rates remained low in the soils from all four stands due to high nitrate ( $${\text{NO}}_{\text{3}}^-- $$ ) immobilization and very fast $${\text{NO}}_{\text{3}}^-- $$ turnover (

Beaver dams are known to raise water tables in mineral soil environments but very little is known about their impact in wetlands, such as peatlands. Peatlands tend to have shallow water tables, and the position and tendency of the water table to fluctuate (i.e. stability) is a factor controlling the system's ability to store carbon and water. Many peatland environments, especially fens, offer ideal habitat for beaver and the potential for beaver dams to influence this link by manipulating water table dynamics requires investigation. Our objective was to determine the influence of beaver dams on water table dynamics of a Rocky Mountain fen. We monitored water tables in the peatland for four years while beaver dams were intact and two years after they were breached by an extreme flood event. We found that, because of the unique way in which dams were built, they connected the peatland to the stream and raised and stabilized already high water tables within a 150-m radius. Beaver-mediated changes to peatland water table regimes have the potential to enhance carbon sequestration and the peatland's ability to respond to external pressures such as climate change. Furthermore, beaver dams increased surface and groundwater storage, which has implications for regional water balances, especially in times of drought.

Net mineralization and nitrification in surface forest soils were measured in upland forest stands and valley peatlands using in situ soil incubations at two headwater catchments of Harp Lake, Ontario from July 1995 to October 1996. No difference in either net N mineralization or nitrification was observed between the two adjacent catchments despite differences in catchment N export. Annual rates of net N mineralization in surface 10 cm were higher in forest soils of the deciduous (11.5 ± 3.1 g/m2; mean ± SE) and conifer-mixed (conifer-hardwoods) (13.9 ± 2.3 g/m2) stands than in peatland soils (1.6 ± 0.6 g/m2). Mean annual nitrification rates were higher in deciduous soils (6.6 ± 0.7 g N/m2) than in mixed stands (1.9 ± 0.6 g N/m2) and peatland soils (0.1 ± 0.2 g N/m2). Annual net N mineralization and nitrification were correlated with variations in soil C and N content and moisture associated with different forest stands. Frequent winter incubations indicate that net mineralization and nitrification under snow cover in upland surface soils can contribute as much as 49 and 23% of the annual net production, respectively. The importance of forest vegetation patterns, winter N transformations, and dissolved organic N pools to total N and NO3- cycling and leaching in these catchments is discussed.

Sibbald Research Wetland is a 1.3 km2 peatland in the foothills of the Rocky Mountains. The primary research foci are 1) the influence of beaver ponds on mountain peatland hydrology and 2) the potential influence of climate change on these beaver-impacted peatlands. This paper summarizes initial results and implications of the research.