Catchment topography and wetland geomorphology drive macroinvertebrate community structure and juvenile salmonid distributions in south-central Alaska headwater streams

King, Ryan S.; Walker, Coowe M.; Whigham, Dennis F.; Baird, Steven J.; Back, Jeffrey A.

doi:10.1899/11-109.1

Cited by 18 publications

(16 citation statements)

References 68 publications

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“…We suspect that high-elevation watersheds tended to be colder because these sites had snowpacks that persisted into early June (http://www.wcc.nrcs.usda.gov/snow/), extending the inputs of cold meltwater (Caissie 2006;Luce et al 2014;Lisi et al 2015). Wetlands, by contrast, lead to warmer stream temperatures because of surface or near-surface flow paths and flat topographies that produce longer residence times and receive more direct radiation than groundwater flow paths (King et al 2012;Callahan et al 2014). Watershed elevation and, to a lesser extent, wetland cover were correlated with other predictors representing a gradient of characteristics associated with elevation.…”

Section: Watershed Drivers Of Variation In Stream Thermal Regimesmentioning

confidence: 99%

Summer temperature regimes in southcentral Alaska streams: watershed drivers of variation and potential implications for Pacific salmon

Mauger

Shaftel

Leppi³

et al. 2017

Can. J. Fish. Aquat. Sci.

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Abstract:Climate is changing fastest in high-latitude regions, focusing our research on understanding rates and drivers of changing temperature regimes in southcentral Alaska streams and implications for salmon populations. We collected continuous water and air temperature data during open-water periods from 2008 to 2012 in 48 nonglacial salmon streams across the Cook Inlet basin spanning a range of watershed characteristics. The most important predictors of maximum temperatures, expressed as mean July temperature, maximum weekly average temperature, and maximum weekly maximum temperature (MWMT), were mean elevation and wetland cover, while thermal sensitivity (slope of the stream-air temperature relationship) was best explained by mean elevation and area. Although maximum stream temperatures varied widely between years and across sites (8.4 to 23.7°C), MWMT at most sites exceeded established criterion for spawning and incubation (13°C), above which chronic and sublethal effects become likely, every year of the study, which suggests salmon are already experiencing thermal stress. Projections of MWMT over the next ϳ50 years suggest these criteria will be exceeded at more sites and by increasing margins.Résumé : Les changements climatiques sont les plus rapides dans les régions de haute latitude, et nos travaux tentent de comprendre les taux et facteurs associés à l'évolution des régimes thermiques dans les cours d'eau du centre-sud de l'Alaska et leurs répercussions sur les populations de saumons. Nous avons recueilli de manière continue des données de température de l'eau et de l'air durant des périodes d'eau libre de 2008 à 2012 dans 48 cours d'eau non glaciaires à saumons à la grandeur du bassin versant du golfe de Cook représentant un éventail de caractéristiques hydrographiques. Les plus importantes variables prédictives des températures maximums, exprimées comme étant la température moyenne en juillet, la température moyenne hebdomadaire maximum et la température maximum hebdomadaire maximum (TMHM), étaient l'altitude moyenne et la couverture de milieux humides, alors que l'altitude moyenne et la superficie étaient les variables qui expliquaient le mieux la sensibilité thermique (la pente de la relation entre la température du cours d'eau et celle de l'air). Si les températures maximums du cours d'eau variaient beaucoup (de 8,4 à 23,7°C) d'une année et d'un emplacement à l'autre, la TMHM dans la plupart des emplacements dépassait le seuil établi pour le frai et l'incubation (13°C) au-delà duquel des effets chroniques et sublétaux deviennent probables, chaque année de l'étude, donnant à penser que les saumons sont déjà en situation de stress thermique. Les projections de la TMHM pour les ϳ50 prochaines années portent à croire que ces seuils seront dépassés dans un nombre croissant d'emplacements et par une plus grande marge. [Traduit par la Rédaction]

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Section: Watershed Drivers Of Variation In Stream Thermal Regimesmentioning

confidence: 99%

Summer temperature regimes in southcentral Alaska streams: watershed drivers of variation and potential implications for Pacific salmon

Mauger

Shaftel

Leppi³

et al. 2017

Can. J. Fish. Aquat. Sci.

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“…Headwater streams on the Kenai Peninsula provide critical rearing habitat for numerous salmonids, with recent studies showing that these headwater streams in our study area may support up to ¼ million salmonids and that juvenile salmon are present in numerous headwater stream habitat types and in a wide range of size classes (King et al ., ). The upper lethal temperature limit for anadromous Pacific salmonids generally ranges from about 23 to 29°C, with a preferred upper temperature limit that ranges from 12 to 14°C (Bjornn and Reiser, ).…”

Section: Discussionmentioning

confidence: 98%

“…A low FWS corresponds to a drainage area with a low gradient, high wetness hydrogeologic setting near the stream (e.g., drainage‐way setting), whereas a high FWS corresponds to a high gradient, low wetness hydrogeologic setting along flow paths near the stream. While FWS and the TWI are similar, the FWS is easier to understand and communicate because it is expressed as a percentage and is not dependent on watershed size (King et al ., ; Walker et al ., ).…”

Section: Methodsmentioning

confidence: 97%

“…(). FWS is calculated for an individual pixel in the watershed by using the following equation:

FWS = \sum false(italicβ i \cdot {FAC}_{i} false) / \sum false({FAC}_{i} false),

where βi is the pixel slope, and FAC i is the flow accumulation value of pixel i (excluding the stream channel), for all pixels in the area draining to an outlet point (King et al ., ; Walker et al ., ). The FWS values reported in this study correspond to the outlet of the drainage area directly upstream of each study site.…”

Section: Methodsmentioning

confidence: 99%

“…These species are important to local and regional economies through recreational and commercial fishing. Recent studies have found juvenile salmonids in Kenai Lowland headwater streams in both spring and summer indicating their importance as rearing and overwintering habitats (Walker et al ., , ; King et al ., ). Walker et al .…”

Section: Introductionmentioning

confidence: 99%

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Controls on Temperature in Salmonid‐Bearing Headwater Streams in Two Common Hydrogeologic Settings, Kenai Peninsula, Alaska

Callahan

Rains

Bellino

et al. 2014

J American Water Resour Assoc

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Headwater streams are the most numerous in terms of both number and length in the conterminous United States and play important roles as spawning and rearing grounds for numerous species of anadromous fish. Stream temperature is a controlling variable for many physical, chemical, and biological processes and plays a critical role in the overall health and integrity of a stream. We investigated the controls on stream temperature in salmon‐bearing headwater streams in two common hydrogeologic settings on the Kenai Peninsula, Alaska: (1) drainage‐ways, which are low‐gradient streams that flow through broad valleys; and (2) discharge‐slopes, which are high gradient streams that flow through narrow valleys. We hypothesize local geomorphology strongly influences surface‐water and groundwater interactions, which control streamflow at the network scale and stream temperatures at the reach scale. The results of this study showed significant differences in stream temperatures between the two hydrogeologic settings. Observed stream temperatures were higher in drainage‐way sites than in discharge‐slope sites, and showed strong correlations as a continuous function with the calculated topographic metric flow‐weighted slope. Additionally, modeling results indicated the potential for groundwater discharge to moderate stream temperature is not equal between the two hydrogeologic settings, with groundwater having a greater moderating effect on stream temperature at the drainage‐way sites.

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Experimental studies and practical challenges in fluvial geomorphology

Métivier

Paola

Kozareck

et al. 2016

Tools in Fluvial Geomorphology

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Catchment topography and wetland geomorphology drive macroinvertebrate community structure and juvenile salmonid distributions in south-central Alaska headwater streams

Cited by 18 publications

References 68 publications

Summer temperature regimes in southcentral Alaska streams: watershed drivers of variation and potential implications for Pacific salmon

Summer temperature regimes in southcentral Alaska streams: watershed drivers of variation and potential implications for Pacific salmon

Controls on Temperature in Salmonid‐Bearing Headwater Streams in Two Common Hydrogeologic Settings, Kenai Peninsula, Alaska

Experimental studies and practical challenges in fluvial geomorphology

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