Ecological responses to experimental glacier-runoff reduction in alpine rivers

Cauvy‐Fraunié, Sophie; Andino, Patricio; Espinosa, Rodrigo; Calvez, Roger; Jacobsen, Dean; Dangles, Olivier

doi:10.1038/ncomms12025

Cited by 66 publications

(53 citation statements)

References 51 publications

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“…With a reduction in glacial meltwater this environmental filter will weaken or eventually completely disappear, allowing colonization through more competitive species from further downstream leading to the possible extinction of these highly adapted endemic 'glacial' species. These results were confirmed more recently in a flow manipulation study, where the glacial meltwater contribution was artificially manipulated (diverted and after a period of time reintegrated) and the resulting changes in algae and macro-invertebrate composition monitored over a period of several years (Cauvy-Fraunié et al, 2016). Their results highlight that following a reduction in glacial meltwater, benthic algal and macroinvertebrate herbivore biomass increased and macroinvertebrate community composition changed within a matter of days to a few weeks, while recolonization by the original species after restoring the previous flow regime takes approximately 30 times longer.…”

Section: Downstream Ecological Impactssupporting

confidence: 58%

Rapid decline of snow and ice in the tropical Andes – Impacts, uncertainties and challenges ahead

Vuille

Carey

Huggel

et al. 2018

Earth-Science Reviews

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258

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Glaciers in the tropical Andes have been retreating for the past several decades, leading to a temporary increase in dry season water supply downstream. Projected future glacier shrinkage, however, will lead to a long-term reduction in dry season river discharge from glacierized catchments. This glacier retreat is closely related to the observed increase in high-elevation, surface air temperature in the region. Future projections using a simple freezing level height-equilibrium-line altitude scaling approach suggest that glaciers in the inner tropics, such as Antizana in Ecuador, may be most vulnerable to future warming while glaciers in the more arid outer tropics, such as Zongo in Bolivia, may persist, albeit in a smaller size, throughout the 21st century regardless of emission scenario. Nonetheless many uncertainties persist, most notably problems with accurate snowfall measurements in the glacier accumulation zone, uncertainties in establishing accurate thickness measurements on glaciers, unknown future changes associated with local-scale circulation and cloud cover affecting glacier energy balance, the role of aerosols and in particular black carbon deposition on Andean glaciers, and the role of groundwater and aquifers interacting with glacier meltwater.The reduction in water supply for export-oriented agriculture, mining, hydropower production and human consumption are the most commonly discussed concerns associated with glacier retreat, but many other aspects including glacial hazards, tourism and recreation, and ecosystem integrity are also affected by glacier retreat. Social and political problems surrounding water allocation for subsistence farming have led to conflicts due to lack of adequate water governance. Local water management practices in many regions reflect cultural belief systems, perceptions and spiritual values and glacier retreat in some places is seen as a threat to these local livelihoods.Comprehensive adaptation strategies, if they are to be successful, therefore need to consider science, policy, culture and practice, and involve local populations. Planning needs to be based not only on future scenarios derived from physically-based numerical models, but must also consider societal needs, economic agendas, political conflicts, socioeconomic inequality and cultural values. This review elaborates on the need for adaptation as well as the challenges and constraints many adaptation projects are faced with, and lays out future directions where opportunities exist to develop successful, culturally acceptable and sustainable adaptation strategies.

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Section: Downstream Ecological Impactssupporting

confidence: 58%

Rapid decline of snow and ice in the tropical Andes – Impacts, uncertainties and challenges ahead

Vuille

Carey

Huggel

et al. 2018

Earth-Science Reviews

Self Cite

258

213

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“…Andean streams with unmanaged conditions are known for their high levels of dissolved oxygen and low nutrient concentrations, providing suitable conditions for benthic fauna colonisation (Ríos‐Touma, Encalada, & Prat Fornells, ). Changing from perennial to intermittent conditions would require Andean streams surpassing thresholds of hydrosystem function and structure (Cauvy‐Fraunié et al., ), a potential scenario if managed streams undergo sustained flow reductions beyond the observed minimum flow condition. On the one hand, an e‐flow threshold of 40% in managed streams coincided with flows where we found the bulk of benthic fauna in unmanaged streams.…”

Section: Discussionmentioning

confidence: 99%

“…For example, in tropical Andean streams, Cauvy‐Fraunié et al. () reported benthic algae and herbivores shifting from low to a high level of biomass with certain level of flow alteration. Changes in flow–benthic fauna relationships are known as thresholds and are of particular interest for managing water ecosystems (Andersen, Carstensen, Hernandez‐Garcia, & Duarte, ; Dodds, Clements, Gido, Hilderbrand, & King, ; Baker & King, ).…”

Section: Introductionmentioning

confidence: 99%

“…Changes in flow–benthic fauna relationships are known as thresholds and are of particular interest for managing water ecosystems (Andersen, Carstensen, Hernandez‐Garcia, & Duarte, ; Dodds, Clements, Gido, Hilderbrand, & King, ; Baker & King, ). The analysis of thresholds in data‐scarce hydrosystems offers the possibility to understand potential shifts in ecosystem structure and functions resulting from human‐induced changes on flow conditions (Cauvy‐Fraunié et al., ).…”

Section: Introductionmentioning

confidence: 99%

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Streamlined eco‐engineering approach helps define environmental flows for tropical Andean headwaters

et al. 2019

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Applying the environmental flows concept to human‐altered lotic ecosystems continues to face many practical challenges and barriers. Here, we modify a previously proposed framework, the Eco‐Engineering Decision Scaling, for application to part of the water supply system of Quito, Ecuador. Specifically, we used feedback from engineers and water managers to develop a common set of metrics for defining flow‐ecology relationships and assess managed‐flow impacts on stream ecology. At 12 sites over 3 years, we collected flow and benthic invertebrate data (taxonomic richness, taxa important for fish, functional feeding groups, and water quality‐sensitive taxa) during wet and dry seasons. We then used these data to identify flow thresholds (relative to unmanaged flows) where flow withdrawal caused visible ecological impacts. For this system, reduction of flow to 20% of the annual median was detrimental to benthic communities, while reductions to 40% of the annual median flow caused a variety of responses in the system. A trade‐off analysis of weighted metrics showed that a 50% benthic fauna richness could be sustained if dry season flows were maintained between 28% and 40% of the unmanaged median annual flow. This study provides a roadmap for bridging between eco‐engineering theoretical frameworks and the adoption of the environmental flows concept as actionable management thresholds.

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“…Herbivore biomass is the amount in g dry‐weight m −2 of the functional feeding group of macroinvertebrates that primarily live on the algae. Data from Jacobsen et al [] and Cauvy‐Fraunié et al [].…”

Section: Aquatic and Terrestrial Ecologymentioning

confidence: 99%

Toward mountains without permanent snow and ice

et al. 2017

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The cryosphere in mountain regions is rapidly declining, a trend that is expected to accelerate over the next several decades due to anthropogenic climate change. A cascade of effects will result, extending from mountains to lowlands with associated impacts on human livelihood, economy, and ecosystems. With rising air temperatures and increased radiative forcing, glaciers will become smaller and, in some cases, disappear, the area of frozen ground will diminish, the ratio of snow to rainfall will decrease, and the timing and magnitude of both maximum and minimum streamflow will change. These changes will affect erosion rates, sediment, and nutrient flux, and the biogeochemistry of rivers and proglacial lakes, all of which influence water quality, aquatic habitat, and biotic communities. Changes in the length of the growing season will allow low-elevation plants and animals to expand their ranges upward. Slope failures due to thawing alpine permafrost, and outburst floods from glacier-and moraine-dammed lakes will threaten downstream populations. Societies even well beyond the mountains depend on meltwater from glaciers and snow for drinking water supplies, irrigation, mining, hydropower, agriculture, and recreation. Here, we review and, where possible, quantify the impacts of anticipated climate change on the alpine cryosphere, hydrosphere, and biosphere, and consider the implications for adaptation to a future of mountains without permanent snow and ice.

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Ecological responses to experimental glacier-runoff reduction in alpine rivers

Cited by 66 publications

References 51 publications

Rapid decline of snow and ice in the tropical Andes – Impacts, uncertainties and challenges ahead

Rapid decline of snow and ice in the tropical Andes – Impacts, uncertainties and challenges ahead

Streamlined eco‐engineering approach helps define environmental flows for tropical Andean headwaters

Toward mountains without permanent snow and ice

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