Mainstem‐tributary linkages by mayfly migration help sustain salmonids in a warming river network

Uno, Hitoshi; Power, Mary E.

doi:10.1111/ele.12483

Cited by 56 publications

(39 citation statements)

References 50 publications

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“…), suggesting that food availability is limiting in natural streams, and may be a cause of reduced growth. However, pulsed subsidies from the mainstem (Uno and Power ) or the terrestrial environment (Nakano and Murakami , Fausch et al. ) may compensate for reduced instream production.…”

Section: Discussionmentioning

confidence: 99%

Do precipitation extremes drive growth and migration timing of a Pacific salmonid fish in Mediterranean‐climate streams?

Kelson

Carlson

2019

Ecosphere

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Climate change is expected to increase weather extremes and variability, including more frequent weather whiplashes or extreme swings between severe drought and extraordinarily wet years. Shifts in precipitation patterns will alter stream flow regimes, affecting critical life history stages of sensitive aquatic organisms. Understanding how threatened fish species, such as steelhead/rainbow trout (Oncorhynchus mykiss), are affected by stream flows in years with contrasting environmental conditions is important for their conservation. Here, we report how extreme wet and dry years, from 2015 to 2018, affected stream flow patterns in two tributaries to the South Fork Eel River, California, USA, and aspects of O. mykiss ecology, including over‐summer fish growth and body condition as well as spring out‐migration timing. We found that stream flow patterns differed across years in the timing and magnitude of large winter–spring flow events and in summer low‐flow levels. We were surprised to find that differences in stream flows did not impact growth, body condition, or timing of out‐migration of O. mykiss. Fish growth was limited in the late summer in these streams (average of 0.02 ± 0.05 mm/d), but was similar across dry and wet years, and so was end‐of‐summer body condition and pool‐specific biomass loss from the beginning to the end of the summer. Similarly, O. mykiss migrated out of tributaries during the last week of March/first week of April regardless of the timing of spring flow events. We suggest that the muted response to inter‐annual hydrologic variability is due to the high quality of habitat provided by these unimpaired, groundwater‐fed tributaries. Similar streams that are likely to maintain cool temperatures and sufficient base flows, even in the driest years, should be a high priority for conservation and restoration efforts.

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Section: Discussionmentioning

confidence: 99%

Do precipitation extremes drive growth and migration timing of a Pacific salmonid fish in Mediterranean‐climate streams?

Kelson

Carlson

2019

Ecosphere

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“…For life‐history shifts and reproductive migrations that are cued by warmer temperatures and longer days (Milner‐Gulland et al, ; Winkler et al, ), the resulting carcasses enter a recipient ecosystem primed to use added nutrients for production. Because the phenology of these events is often conserved across individuals of a species, mortality events are often experienced by large numbers of individuals at the same time, which can result in a major pulse of carcasses (Baxter et al, ; Uno & Power, ). A similar pulse of carcasses can occur due to mass mortality from a catastrophic event or disease outbreak, the latter of which is the factor most often associated with mass mortality events across all animal taxa (Fey et al, ).…”

Section: Animal Vector Characteristicsmentioning

confidence: 99%

Context dependency of animal resource subsidies

2018

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The transport of resource subsidies by animals has been documented across a range of species and ecosystems. Although many of these studies have shown that animal resource subsidies can have significant effects on nutrient cycling, ecosystem productivity, and food‐web structure, there is a great deal of variability in the occurrence and strength of these effects. Here we propose a conceptual framework for understanding the context dependency of animal resource subsidies, and for developing and testing predictions about the effects of animal subsidies over space and time. We propose a general framework, in which abiotic characteristics and animal vector characteristics from the donor ecosystem interact to determine the quantity, quality, timing, and duration (QQTD) of an animal input. The animal input is translated through the lens of recipient ecosystem characteristics, which include both abiotic and consumer characteristics, to yield the QQTD of the subsidy. The translated subsidy influences recipient ecosystem dynamics through effects on both trophic structure and ecosystem function, which may both influence the recipient ecosystem's response to further inputs and feed back to influence the donor ecosystem. We present a review of research on animal resource subsidies across ecosystem boundaries, placed within the context of this framework, and we discuss how the QQTD of resource subsidies can influence trophic structure and ecosystem function in recipient ecosystems. We explore the importance of understanding context dependency of animal resource subsidies in increasingly altered ecosystems, in which the characteristics of both animal vectors and donor and recipient ecosystems may be changing rapidly. Finally, we make recommendations for future research on animal resource subsidies, and resource subsidies in general, that will increase our understanding and predictive capacity about their ecosystem effects.

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“…However, when no nearby propagule sources exist (e.g., in headwater dams, or in highly dammed river basins) the Moran effect may increase the effective risk of functional collapse. Many individual traits are linked to species’ functional roles in ecosystems, e.g., feeding strategies are linked to organic matter processing (Graça, ); and voltinism, flying, and drift are linked to terrestrial and in‐stream subsidies (Baxter, Fausch, & Carl Saunders, ; Uno & Power, ). Additionally, multifunctionality (i.e., trait richness, and diversity of trait combinations across community members) is positively associated with the maintenance of ecosystem processes and services (Cadotte et al., ).…”

Section: Discussionmentioning

confidence: 99%

Detrimental effects of a novel flow regime on the functional trajectory of an aquatic invertebrate metacommunity

Ruhí

Dong

McDaniel

et al. 2018

Global Change Biology

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Novel flow regimes resulting from dam operations and overallocation of freshwater resources are an emerging consequence of global change. Yet, anticipating how freshwater biodiversity will respond to surging flow regime alteration requires overcoming two challenges in environmental flow science: shifting from local to riverscape-level understanding of biodiversity dynamics, and from static to time-varying characterizations of the flow regime. Here, we used time-series methods (wavelets and multivariate autoregressive models) to quantify flow-regime alteration and to link time-varying flow regimes to the dynamics of multiple local communities potentially connected by dispersal (i.e., a metacommunity). We studied the Chattahoochee River below Buford dam (Georgia, U.S.A.), and asked how flow regime alteration by a large hydropower dam may control the long-term functional trajectory of the downstream invertebrate metacommunity. We found that seasonal variation in hydropeaking synchronized temporal fluctuations in trait abundance among the flow-altered sites. Three biological trait states describing adaptation to fast flows benefitted from flow management for hydropower, but did not compensate for declines in 16 "loser" traits. Accordingly, metacommunity-wide functional diversity responded negatively to hydropeaking intensity, and stochastic simulations showed that the risk of functional diversity collapse within the next 4 years would decrease by 17% if hydropeaking was ameliorated, or by 9% if it was applied every other season. Finally, an analysis of 97 reference and 23 dam-affected river sites across the U.S. Southeast suggested that flow variation at extraneous, human-relevant scales (12-hr, 24-hr, 1-week) is relatively common in rivers affected by hydropower dams. This study advances the notion that novel flow regimes are widespread, and simplify the functional structure of riverine communities by filtering out taxa with nonadaptive traits and by spatially synchronizing their dynamics. This is relevant in the light of ongoing and future hydrologic alteration due to climate non-stationarity and the new wave of dams planned globally.

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Mainstem‐tributary linkages by mayfly migration help sustain salmonids in a warming river network

Cited by 56 publications

References 50 publications

Do precipitation extremes drive growth and migration timing of a Pacific salmonid fish in Mediterranean‐climate streams?

Do precipitation extremes drive growth and migration timing of a Pacific salmonid fish in Mediterranean‐climate streams?

Context dependency of animal resource subsidies

Detrimental effects of a novel flow regime on the functional trajectory of an aquatic invertebrate metacommunity

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