Rood, Stewart
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- ItemRegional differences in high elevation snowpack decline along the North American Rocky Mountains(Wiley, 2025) Zanewich, Karen P.; Rood, StewartThe Rocky Mountains (RM) provide the ‘water towers’ for western North America, with deep winter snowpack accumulations that melt to contribute flows for the extensively utilised Columbia, Colorado, Saskatchewan, Missouri and Rio Grande River systems. With climate change, winter and spring warming are increasing seasonal and elevational rain versus snow proportions and altering the annual patterns of snowpack accumulation and melt. Prior studies have reported declines in snowpack extent or water content, especially on an index date, April 1. These declines could reflect reductions in the total annual snowpacks or earlier transitions to snowmelt. To resolve these influences, we assessed daily snowpack patterns at 314 snow pillow stations in the higher elevations along the 2500 km transboundary RM corridor, over three decades from 1991 to 2020. We found regional differentiation, with little change in the maximum snow water equivalent (SWEmax) or its timing (Daymax) in the most-northerly, Canadian RM region (BC, AB); slight declines in the Northern US (ID, MT, WY) and Central US (UT, CO); and major declines in the Southern US (AZ, NM; average ΔSWEmax: −2%/yr; ΔDaymax: −0.75%/yr). With compound influences of declining SWEmax and earlier Daymax, the April 1 SWE (SWEApr1) was more responsive, with progressive decline at some Northern US and Central US stations, and steep decline in the Southern US region (ΔSWEApr1: −6.5%/yr). Due to these compound influences, we recommend that future analyses include snowpack maxima and seasonality as well as April 1 measures, since that precedes the peak snowpack for higher elevation and northern sites, but follows the peak for lower and southern sites, confounding trend comparisons. Thus, higher elevation RM snowpacks are declining but with considerable latitudinal variation, displaying slight change in magnitude and seasonality in the northern regions, and greater change southward. These patterns contrast with some other climate change patterns that display increasing responsivity with higher latitude.
- ItemCollateral benefits: river flow normalization for endangered fish enabled riparian rejuvenation(Wiley, 2024) Rood, Stewart B.; Hoffman, Gregory C.; Merz, Norm; Anders, Paul; Benjankar, Rohan; Burke, Michael; Egger, Gregory; Polzin, Mary Louise; Soults, ScottLike most rivers worldwide, the transboundary North American Kootenay/i River has experienced multiple impacts including watershed developments, river channelization, and floodplain clearing, draining, and diking. Construction of Libby Dam was authorized by the 1964 Columbia River Treaty (CRT) between the United States and Canada, and in 1975 began regulating downstream flows for flood risk management and hydropower generation. Following cumulative impacts, the endemic Kootenai River White Sturgeon population collapsed and was designated as endangered in 1994 (U.S. Endangered Species Act). Subsequent Biological Opinions from the U.S. Fish and Wildlife Service prescribed Libby Dam operations to provide springtime flow pulses for sturgeon spawning. These provided the unanticipated benefit of substantial seedling recruitment of native and introduced riparian cottonwoods and willows. The regulated flow regime was further adaptively managed to provide a more normative (natural) regime, to balance ecological functions with flood risk management and hydropower generation. The broadened ecological considerations would be consistent with the proposed priorities for the modernization of the international CRT. The observed responses revealed that (1) diverse aquatic and riparian organisms are dependent on common river flow characteristics; (2) a normalized flow regime provided substantial ecological benefits; and (3) due to multiple influences, hybrid ecosystems develop along regulated rivers, with a blending of natural and altered processes and communities. For other regulated rivers, we recommend that (1) high springtime flows be allowed, as feasible; (2) followed by the gradual post-peak recession; and (3) the maintenance of sufficient flows through the warm and dry interval of mid to late summer.
- ItemEcological impacts of shortening fire return intervals on boreal peatlands and transition zones using integrated in situ field sampling and lidar approaches(Wiley, 2022) Jones, Emily; Chasmer, Laura; Devito, Kevin; Rood, Stewart; Hopkinson, ChristopherAridity associated with rising air temperatures in northern latitudes is expected to contribute to increased frequency of wildland fires. Here, we examined regenerating vegetation following short return interval (SRI) fire (56 years post-fire) compared to long return interval (LRI) fire (>80 years post-fire) in boreal peatlands and their adjacent transitional areas. The objectives of this study were to quantify if differences exist between (1) peatland and transitional soil characteristics in LRI versus SRI areas and (2) regenerating vegetation species, structural characteristics and diversity. We also determined if patterns of vegetation structural characteristics observed using field data also occur across the broader landscape using airborne lidar data. The Utikuma Region Study Area (URSA) is located in central Alberta, Canada. Here, 19 peatlands were sampled, coincident with an airborne lidar survey of the broader region, where 120 peatlands in short and long fire return intervals were identified. We found that SRI transitional areas had significantly deeper organic soil deposits than those found in LRI (p < 0.0001). Proportions of regenerating species differed significantly between peatlands and transitional areas in SRI versus LRI, where greater proportion of coniferous species were observed in LRI. Deciduous transitional–upland species and taller post-fire vegetation heights were more commonly found SRI peatlands compared with LRI. This suggest that fires with SRIs in this region may result in enhanced deciduous succession, which may transition boreal peatlands into ecosystems that have some characteristics of transitional and upland forests.
- ItemGravel-bed river floodplains are the ecological nexus of glaciated mountain landscapes(American Association for the Advancement of Science, 2016) Hauer, F. Richard; Locke, Harvey; Dreitz, Victoria J.; Hebblewhite, Mark; Lowe, Winsor H.; Muhfield, Clint C.; Nelson, Cara R.; Proctor, Michael F.; Rood, Stewart B.Gravel-bed river floodplains in mountain landscapes disproportionately concentrate diverse habitats, nutrient cycling, productivity of biota, and species interactions. Although stream ecologists know that river channel and floodplain habitats used by aquatic organisms are maintained by hydrologic regimes that mobilize gravel-bed sediments, terrestrial ecologists have largely been unaware of the importance of floodplain structures and processes to the life requirements of a wide variety of species. We provide insight into gravel-bed rivers as the ecological nexus of glaciated mountain landscapes. We show why gravel-bed river floodplains are the primary arena where interactions take place among aquatic, avian, and terrestrial species from microbes to grizzly bears and provide essential connectivity as corridors for movement for both aquatic and terrestrial species. Paradoxically, gravel-bed river floodplains are also disproportionately unprotected where human developments are concentrated. Structural modifications to floodplains such as roads, railways, and housing and hydrologicaltering hydroelectric or water storage dams have severe impacts to floodplain habitat diversity and productivity, restrict local and regional connectivity, and reduce the resilience of both aquatic and terrestrial species, including adaptation to climate change. To be effective, conservation efforts in glaciated mountain landscapes intended to benefit the widest variety of organisms need a paradigm shift that has gravel-bed rivers and their floodplains as the central focus and that prioritizes the maintenance or restoration of the intact structure and processes of these critically important systems throughout their length and breadth.
- ItemThe Biology and Management of Southern Alberta's Cottonwoods(Lethbridge, AB : University of Lethbridge, 1991, 1991-02) Rood, Stewart B.; Mahoney, John M.Proceedings of the University of Lethbridge conference, May 4 to 6, 1990.