Recent and subfossil diatom assemblages as indicators of environmental change (including fish introduction) in a high-mountain lake

Cantonati, Marco; Zorza, Raffaella; Bertoli, Marco; Pastorino, Paolo; Salvi, Gianguido; Platania, Giulia; Prearo, Marino; Pizzul, Elisabetta

doi:10.1016/j.ecolind.2021.107603

Cited by 23 publications

(17 citation statements)

References 70 publications

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“…However, fewer species change in abundances at the impact reach, may have influenced the non-significant effect of the Reach x Period interaction in Ventín. Among the most abundant diatom species in the Ventín stream was Humidophila schmassmannii, a relatively rare species that prefers weakly mineralised freshwater oligotrophic environments [94,95]. The Shannon-Wiener diversity index values were higher than in other siliceous streams [96], and increased over the summer as in other studies [97].…”

Section: Eucalypt Leachates Influencing Diatom Speciesmentioning

confidence: 76%

Short-Term Effect of Eucalyptus Leachates on Green Food Webs in Headwaters

González-Paz

Gestido

Delgado

et al. 2022

Water

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Despite the reported allelopathic nature of the Eucalyptus genus, eucalypt leachates have unknown effects on the trophic base of stream green food webs. Eucalypt plantations have increased worldwide, including riparian ecosystems. We aimed to test whether short-term eucalypt leachates might alter water chemistry, periphytic algal biomass and diatoms, and herbivorous invertebrates’ (i.e., scrapers). We studied two oligotrophic and well-preserved headwaters from NW Spain. The experiment followed a before-after control-impact paired (BACIp) design, with weekly sampling before and after eucalypt leaves addition to streams. In the stream with lower discharge, the eucalypt treatments seemed to affect increases in biomass accrual (Chl-a) and diatom assemblages, disfavouring sensitive species (e.g., Eunotia minor and Achnanthidium pyrenaicum). Therefore, the ecological status was reduced from high to good. In the stream with higher discharge, invertebrate assemblages changed with scrapers having their abundances modified in comparison with the control (e.g., Habrophlebia sp. and Elmidae). Results suggest that eucalypt leaves leachates exert toxic effects on periphyton and on diatom and invertebrate assemblages, and this effect might be mediated by discharge. Alterations at the base of stream food webs may compromise their good ecological status. Further studies are necessary to identify whether this toxicity is due to allelopathic processes.

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Section: Eucalypt Leachates Influencing Diatom Speciesmentioning

confidence: 76%

Short-Term Effect of Eucalyptus Leachates on Green Food Webs in Headwaters

González-Paz

Gestido

Delgado

et al. 2022

Water

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“…and chironomids, to provide evidence of fish predation in lakes (Skov et al ., 2010; Jeppesen et al ., 1996; Johnson et al ., 1990; Sweetman & Smol, 2006; Milardi et al ., 2016). In addition, diatoms can respond to various types of fish introductions through a range of mechanisms, such as trophic cascades and nutrient enrichment (Drake & Naiman, 2000; Jacques et al ., 2005; Cantonati et al ., 2021). For example, diatom communities responded to fluctuations in salmon populations due to an increase in salmon‐derived nutrients in a lake system from the decomposition of salmon carcasses (Holtham et al ., 2004; Gregory‐Eaves et al ., 2003).…”

Section: Methods For Measuring the Impact Of Disturbance On Native Fr...mentioning

confidence: 99%

An integrative approach to assess the impact of disturbance on native fish in lakes

Thomson‐Laing,

Schallenberg,

Kelly

et al. 2023

Biological Reviews

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Freshwater fish are in a perilous state with more than 30% of species considered critically endangered. Yet significant ecological and methodological complexities constrain our ability to determine how disturbances are impacting native fish communities. We review current methods used to assess the responses of fish communities, especially native fish, to disturbances, with a focus on lakes. These methods include contemporary population surveys, manipulative experimental approaches, paleolimnological approaches and Indigenous Knowledge and social histories. We identify knowledge gaps, such as a lack of baseline data for native fish, an inability to assess the impact of historical disturbances, stressor response dynamics in contemporary multi‐stressor environments, and natural disturbance regimes. Our assessment of the current methods highlights challenges to filling these knowledge gaps using the reviewed methods. We advocate strongly for the implementation of an integrative approach that combines emerging technologies (i.e. molecular‐based techniques in contemporary surveys and paleolimnology) and underutilised knowledge streams (i.e. Indigenous Knowledge and social histories) which should be used in concert with conventional methods. This integrative approach will allow researchers to determine the key drivers of decline and the degree of change, which will enable more informed and successful management actions.

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“…Here, in the autotrophic fraction of the phytoplankton assemblage, diatoms (Cyclotella comensis and Fragilaria nanana) replaced the small cyanobacteria. These two species are widely used as an indicator of physicochemical changes (Cantonati et al, 2021), especially increased water temperatures in alpine lakes (Catalan, Pla, et al, 2002;Sochuliaková et al, 2018). In addition, the PE:PC ratio changed during the overturn, PC becoming dominant over PE.…”

Section: Phytoplankton Functional Changesmentioning

confidence: 99%

Phytoplankton assemblage shifts with dissolved organic matter properties: A functional perspective for sentinel lakes

et al. 2022

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1. Climate change is altering both dissolved organic matter (DOM) properties and phytoplankton dynamics in lakes. High-altitude lakes are good sentinels of global change. However, their value as sentinels depends on how well we understand their functioning. This study analysed physical, chemical and biological data during three pre-defined periods running from complete ice-cover right to the end of the ice-free season, in a high-altitude oligotrophic lake. A functional approach was used to assess how relationships between DOM and the planktonic community vary over time. 2. Phytoplankton functional change was found to occur with shifts in DOM. During the ice-influenced period, from February to the end of the thaw, the phytoplankton community was dominated by small autotrophs and mixotrophic flagellates and DOM from sediment and terrestrial origin dominated the DOM pool of the lake. Phytoplankton diversity and richness increased during the post-snowmelt overturn period, when terrestrial DOM dominated the DOM pool. Finally, large siliceous autotrophs, competitive under low nitrogen concentrations and high temperature, dominated almost exclusively during the late summer period (LSP).Increased phytoplankton biomass meant that phytoplankton-derived DOM was dominant during the LSP.3. These phenological changes in the phytoplankton community resulted in functional shifts at the base of the food web. Based on the relationships between the variables in the study, it can be deduced that the nature of the relationship between phytoplankton and bacteria progressively shifted from strong top-down control exerted by phytoplankton over bacteria towards predominantly bottomup control at the end of the ice-free season. 4. Synthesis. Using a field survey starting from complete ice-cover and lasting right to the end of the ice-free season in a sentinel lake, we show seasonal shifts in the link between DOM properties and plankton community traits. Differences in environmental conditions and DOM origin explained variation in phytoplankton community structure and function, pointing to seasonal shifts in microbial food K E Y W O R D S functional traits, global change, microbial interactions, mountain lakes, trophic interactions | 47

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Recent and subfossil diatom assemblages as indicators of environmental change (including fish introduction) in a high-mountain lake

Cited by 23 publications

References 70 publications

Short-Term Effect of Eucalyptus Leachates on Green Food Webs in Headwaters

Short-Term Effect of Eucalyptus Leachates on Green Food Webs in Headwaters

An integrative approach to assess the impact of disturbance on native fish in lakes

Phytoplankton assemblage shifts with dissolved organic matter properties: A functional perspective for sentinel lakes

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