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136 results on '"Kopáček, J."'

2. The significance of tree height as a predictor of tree mortality during bark beetle outbreaks in a small catchment

Author

Schmidt, Susanne Isabel, Fluksová, H., Grill, S., Kopáček, J., Schmidt, Susanne Isabel, Fluksová, H., Grill, S., and Kopáček, J.

Abstract

Bark beetle outbreaks damage forests and kill trees worldwide, but many aspects of their dynamics remain unexplained. Our aim was to identify predictors for individual tree deaths within the small (0.7 km2) Plešné Lake catchment in the Šumava National Park in southwestern Czechia. Within this area, >60,000 trees were geo-referenced and categorized from ten aerial images (20 cm spatial resolution) between 2000 and 2015. For each year for which aerial images were available, we calculated tree densities of different categories and diameters. Tree height was evaluated by means of LiDAR in two terrestrial campaigns (2010 and 2011). A machine learning technique was then used to evaluate the most important variables. The resulting relationships were largely nonlinear and differed among years; however, individual trait tree height proved to be the most influential variable in each year. Higher trees were more likely to have died during either the undisturbed phase (2000 and 2003), the disturbed phase (2005–2011), or the recovery phase (2013). Our results indicate that salvage logging may not be the most effective measure for protecting trees in small catchments.

Published
2024

4. Consequence of altered nitrogen cycles in the coupled human and ecological system under changing climate: The need for long-term and site-based research

Author

Shibata, H, Branquinho, C, McDowell, WH, Mitchell, MJ, Monteith, DT, Tang, J, Arvola, L, Cruz, C, Cusack, DF, Halada, L, Kopáček, J, Máguas, C, Sajidu, S, Schubert, H, Tokuchi, N, and Záhora, J

Subjects
Ecology
Abstract

Anthropogenically derived nitrogen (N) has a central role in global environmental changes, including climate change, biodiversity loss, air pollution, greenhouse gas emission, water pollution, as well as food production and human health. Current understanding of the biogeochemical processes that govern the N cycle in coupled human–ecological systems around the globe is drawn largely from the long-term ecological monitoring and experimental studies. Here, we review spatial and temporal patterns and trends in reactive N emissions, and the interactions between N and other important elements that dictate their delivery from terrestrial to aquatic ecosystems, and the impacts of N on biodiversity and human society. Integrated international and long-term collaborative studies covering research gaps will reduce uncertainties and promote further understanding of the nitrogen cycle in various ecosystems.

Published
2015

5. Mountain lakes: Eyes on global environmental change

Author

Moser, K.A., Baron, J.S., Brahney, J., Oleksy, I.A., Saros, J.E., Hundey, E.J., Sadro, S., Kopáček, J., Sommaruga, R., Kainz, M.J., Strecker, A.L., Chandra, S., Walters, D.M., Preston, D.L., Michelutti, N., Lepori, F., Spaulding, S.A., Christianson, K.R., Melack, J.M., and Smol, J.P.

Published
2019
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8. Forest damage and subsequent recovery alter the water composition in mountain lake catchments

Author

Schmidt, Susanne Isabel, Hejzlar, J., Kopáček, J., Paule-Mercado, M.C., Porcal, P., Vystavna, Y., Lanta, V., Schmidt, Susanne Isabel, Hejzlar, J., Kopáček, J., Paule-Mercado, M.C., Porcal, P., Vystavna, Y., and Lanta, V.

Abstract

Forest damage by insect infestation directly affects the trees themselves, but also indirectly affects water quality via soil processes. The changes in water composition may undergo different pathways depending on site-specific characteristics and forest components, especially the proportion of coniferous and deciduous trees. Here, we test whether changes in forest components and the intensity of disturbance can predict the chemical properties of water outflow from affected lake catchments. Information about forest regeneration (a phase dominated by deciduous trees) and the proportions of damaged and healthy coniferous trees and treeless areas were obtained from satellite data. The four study catchments of Prášilské, Laka, Plešné, and Čertovo lakes are geographically close and located in the same mountain range (Šumava Mts., Czech Republic) at similar altitude, but they differ in extents of forest disturbances and recoveries. The water quality measured at the lake catchment outflows differed, and better reflected the development of forest components and health than did meteorological (temperature and precipitation) or hydrological (discharge) variables. Several of the outflow properties (concentrations of inorganic aluminium, protons, potassium, calcium, magnesium, alkalinity, dissolved organic carbon (DOC), nitrate, and total phosphorus), responded catchment-specifically and with different delays to forest disturbance. The most pronounced differences occurred in DOC concentrations, which started to increase in the most disturbed Plešné and Laka catchments 7 and 6 years, respectively, after the peak in tree dieback, but did not increase significantly in the Prášilské catchment, which was disturbed several times during the last 3–4 decades. This study demonstrates an importance of extents of forest disturbances, the following changes in forest composition, and catchment-specific characteristics on water composition.

Published
2022

17. Mountain Lakes: Eyes on Global Environmental Change

Author

Moser, K. A., Baron, J. S., Brahney, Janice, Oleksy, I. A., Saros, J. E., Hundey, E. J., Sadro, S. A., Kopáček, J., Sommaruga, R., Kainz, M. J., Strecker, A. L., Chandra, S., Walters, D. M., Preston, D. L., and Elsevier BV

Subjects
species invasions, climate change, paleolimnology, atmospheric deposition, carbon cycle, Life Sciences, dust, Mountain lakes
Abstract

Mountain lakes are often situated in protected natural areas, a feature that leads to their role as sentinels of global environmental change. Despite variations in latitude, mountain lakes share many features, including their location in catchments with steep topographic gradients, cold temperatures, high incident solar and ultraviolet radiation (UVR), and prolonged ice and snow cover. These characteristics, in turn, affect mountain lake ecosystem structure, diversity, and productivity. The lakes themselves are mostly small, and up until recently, have been characterized as oligotrophic. This paper provides a review and update of the growing body of research that shows that sediments in remote mountain lakes archive regional and global environmental changes, including those linked to climate change, altered biogeochemical cycles, and changes in dust composition and deposition, atmospheric fertilization, and biological manipulations. These archives provide an important record of global environmental change that pre-dates typical monitoring windows. Paleolimnological research at strategically selected lakes has increased our knowledge of interactions among multiple stressors and their synergistic effects on lake systems. Lakes from transectsacross steep climate (i.e., temperature and effective moisture) gradients in mountain regions show how environmental change alters lakes in close proximity, but at differing climate starting points. Such research in particular highlights the impacts of melting glaciers on mountain lakes. The addition of new proxies, including DNA-based techniques and advanced stable isotopic analyses, provides a gateway to addressing novel research questions about global environmental change. Recent advances in remote sensing and continuous, high-frequency, limnological measurements will improve spatial and temporal resolution and help to add records to spatial gaps including tropical and southern latitudes. Mountain lake records provide a unique opportunity for global scale assessments that provide knowledge necessary to protect the Earth system.

Published
2019

20. Widespread diminishing anthropogenic effects on calcium in freshwaters

Author

Weyhenmeyer, G.A., Hartmann, J., Hessen, D.O., Kopáček, J., Hejzlar, J., Jacquet, S., Hamilton, S.K., Verburg, P., Leach, T.H., Schmid, M., Flaim, G., Nõges, T., Nõges, P., Wentzky, Valerie, Rogora, M., Rusak, J.A., Kosten, S., Paterson, A.M., Teubner, K., Higgins, S.N., Lawrence, G., Kangur, K., Kokorite, I., Cerasino, L., Funk, C., Harvey, R., Moatar, F., de Wit, H.A., Zechmeister, T., Weyhenmeyer, G.A., Hartmann, J., Hessen, D.O., Kopáček, J., Hejzlar, J., Jacquet, S., Hamilton, S.K., Verburg, P., Leach, T.H., Schmid, M., Flaim, G., Nõges, T., Nõges, P., Wentzky, Valerie, Rogora, M., Rusak, J.A., Kosten, S., Paterson, A.M., Teubner, K., Higgins, S.N., Lawrence, G., Kangur, K., Kokorite, I., Cerasino, L., Funk, C., Harvey, R., Moatar, F., de Wit, H.A., and Zechmeister, T.

Abstract

Calcium (Ca) is an essential element for almost all living organisms. Here, we examined global variation and controls of freshwater Ca concentrations, using 440 599 water samples from 43 184 inland water sites in 57 countries. We found that the global median Ca concentration was 4.0 mg L−1 with 20.7% of the water samples showing Ca concentrations ≤ 1.5 mg L−1, a threshold considered critical for the survival of many Ca-demanding organisms. Spatially, freshwater Ca concentrations were strongly and proportionally linked to carbonate alkalinity, with the highest Ca and carbonate alkalinity in waters with a pH around 8.0 and decreasing in concentrations towards lower pH. However, on a temporal scale, by analyzing decadal trends in >200 water bodies since the 1980s, we observed a frequent decoupling between carbonate alkalinity and Ca concentrations, which we attributed mainly to the influence of anthropogenic acid deposition. As acid deposition has been ameliorated, in many freshwaters carbonate alkalinity concentrations have increased or remained constant, while Ca concentrations have rapidly declined towards or even below pre-industrial conditions as a consequence of recovery from anthropogenic acidification. Thus, a paradoxical outcome of the successful remediation of acid deposition is a globally widespread freshwater Ca concentration decline towards critically low levels for many aquatic organisms.

Published
2019

24. Regionalisation of chemical variability in European mountain lakes

Author

Camarero, Lluís, Rogora, M., Mosello, R., Anderson, N. J., Barbieri, A., Botev, I., Kernan, M., Kopáček, J., Korhola, A., Lotter, A. F., Muri, G., Postolache, C., Stuchlík, Evzen, Thies, Hansjörg, and Wright, R. F.

Subjects
Chemical classification, Upscaling, Regionalisation, Lakewater chemistry, Mountain lakes
Abstract

18 páginas, 6 tablas, 7 figuras., 1. We carried out a coordinated survey of mountain lakes covering the main ranges across Europe (including Greenland), sampling 379 lakes above the local tree line in 2000. The objectives were to identify the main sources of chemical variability in mountain lakes, define a chemical classification of lakes, and develop tools to extrapolate our results to regional lake populations through an empirical regionalisation or upscaling of chemical properties. 2. We investigated the main causes of chemical variability using factor analysis (FA) and empirical relationships between chemistry and several environmental variables. Weathering, sea salt inputs, atmospheric deposition of N and S, and biological activity in soils of the catchment were identified as the major drivers of lake chemistry. 3. We tested discriminant analysis (DA) to predict the lake chemistry. It was possible to use the lithology of the catchments to predict the range of Ca 2+ and SO4 2) into which a lake of unknown chemistry will decrease. Lakes with lower SO4 2) concentrations have little geologically derived S, and better reflect the variations in atmospheric S loading. The influence of marine aerosols on lakewater chemistry could also be predicted from the minimum distance to the sea and altitude of the lakes. 4. The most remarkable result of FA was to reveal a factor correlated to DOC (positively) and NO3 ) (negatively). This inverse relationship might be the result either of independent processes active in the catchment soils and acting in an opposite sense, or a direct interaction, e.g. limitation of denitrification by DOC availability. Such a relationship has been reported in the recent literature in many sites and at all scales, appearing to be a global pattern that could reflect the link between the C and N cycles. 5. The concentration of NO3 ) is determined by both atmospheric N deposition and the processing capacity of the catchments (i.e. N uptake by plants and soil microbes). The fraction of the variability in NO3 ) because of atmospheric deposition is captured by an independent factor in the FA. This is the only factor showing a clear pattern when mapped over Europe, indicating lower N deposition in the northernmost areas. 6. A classification has been derived which takes into account all the major chemical features of the mountain lakes in Europe. FA provided the criteria to establish the most important factors influencing lake water chemistry, define classes within them, and classify the surveyed lakes into each class. DA can be used as a tool to scale up the classification to unsurveyed lakes, regarding sensitivity to acidification, marine influence and sources of S., Funding was provided by the European Union (EMERGE project EVK1-CT-1999-00032), Spanish Ministry of Science and Technology (CICYT grant REN2000-0889 ⁄GLO), and the Austrian Ministry for Education, Science and Culture.

Published
2009

26. Global change revealed by palaeolimnological records from remote lakes: a review.

Author

Catalán, Jordi, Pla-Rabes, Sergi, Wolfe, Alexander P., Smol, J. P., Rühland, K., Anderson, J., Kopáček, J., Stuchlík, Evzen, Schmidt, R., Koinig, Karin Anne, Camarero, Lluís, Flower, Roger J., Heiri, O., Kamenik, C., Korhola, A., Leavitt, P. R., Psenner, Roland, Renberg, I., Catalán, Jordi, Pla-Rabes, Sergi, Wolfe, Alexander P., Smol, J. P., Rühland, K., Anderson, J., Kopáček, J., Stuchlík, Evzen, Schmidt, R., Koinig, Karin Anne, Camarero, Lluís, Flower, Roger J., Heiri, O., Kamenik, C., Korhola, A., Leavitt, P. R., Psenner, Roland, and Renberg, I.

Abstract

Over recent decades, palaeolimnological records from remote sites have provided convincing evidence for the onset and development of several facets of global environmental change. Remote lakes, defined here as those occurring in high latitude or high altitude regions, have the advantage of not being overprinted by local anthropogenic processes. As such, many of these sites record broad-scale environmental changes, frequently driven by regime shifts in the Earth system. Here, we review a selection of studies from North America and Europe and discuss their broader implications. The history of investigation has evolved synchronously with the scope and awareness of environmental problems. An initial focus on acid deposition switched to metal and other types of pollutants, then climate change and eventually to atmospheric deposition-fertilising effects. However, none of these topics is independent of the other, and all of them affect ecosystem function and biodiversity in profound ways. Currently, remote lake palaeolimnology is developing unique datasets for each region investigated that benchmark current trends with respect to past, purely natural variability in lake systems. Fostering conceptual and methodological bridges with other environmental disciplines will upturn contribution of remote lake palaeolimnology in solving existing and emerging questions in global change science and planetary stewardship.

Published
2013

27. Seasonal ecosystem variability in remote mountain lakes: implications for detecting climatic signals in sediment records

Author

Catalán, Jordi, Ventura, Marc, Brancelj, A., Granados, I., Thies, Hansjörg, Nickus, Ulrike, Korhola, A., Lotter, A. F., Barbieri, A., Stuchlík, Evzen, Lien, P., Bitusik, P., Buchaca, Teresa, Camarero, Lluís, Goudsmit, G. H., Kopáček, J., Lemcke, G., Livingstone, D. M., Müller, B., Rautio, M., Sisko, M., Sorvari, S., Sporka, F., Strunecky, O., Toro, M., Palaeobotany and Palynology, Universiteit Utrecht, and Dep Biologie

Subjects
Oxygen, Chlorophyll, Major chemicals, Alpine lakes, Other biological specialities, International, Nutrients, Thermal regime, Life sciences
Abstract

22 páginas, 12 figuras, 20 tablas., Weather variation and climate fluctuations are the main sources of ecosystem variability in remote mountain lakes. Here we describe the main patterns of seasonal variability in the ecosystems of nine lakes in Europe, and discuss the implications for recording climatic features in their sediments. Despite the diversity in latitude and size, the lakes showed a number of common features. They were ice-covered between 5–9 months, and all but one were dimictic. This particular lake was long and shallow, and wind action episodically mixed the water column throughout the ice-free period. All lakes showed characteristic oxygen depletion during the ice-covered-period, which was greater in the most productive lakes. Two types of lakes were distinguished according to the number of production peaks during the ice-free season. Lakes with longer summer stratification tended to have two productive periods: one at the onset of stratification, and the other during the autumn overturn. Lakes with shorter stratification had a single peak during the ice-free period. All lakes presented deep chlorophyll maxima during summer stratification, and subsurface chlorophyll maxima beneath the ice. Phosphorus limitation was common to all lakes, since nitrogen compounds were significantly more abundant than the requirements for the primary production observed. The major chemical components present in the lakes showed a short but extreme dilution during thawing. Certain lake features may favour the recording of particular climatic fluctuations, for instance: lakes with two distinct productive periods, climatic fluctuations in spring or autumn (e.g., through chrysophycean cysts); lakes with higher oxygen consumption, climatic factors affecting the duration of the ice-cover (e.g., through low-oxygen tolerant chironomids); lakes with higher water retention time; changes in atmospheric deposition (e.g., through carbon or pigment burial); lakes with longer stratification, air temperature changes during summer and autumn (e.g., through all epilimnetic species)., This study was supported by the European Commission, Environment and Climate Programme, contract ENV4 CT95 0007 (MOLAR) and by the Swiss Federal Office of Education and Science (grant no. 95.0518-1).

Published
2002

28. Phosphate sorption characteristics of European alpine soils

Author

Kana, J., Kopáček, J., Camarero, Lluís, García-Pausas, J., Kana, J., Kopáček, J., Camarero, Lluís, and García-Pausas, J.

Abstract

We evaluated the chemical properties controlling phosphate (PO4–P) sorption characteristics of alpine soils at elevations of 1725 to 2900 m above sea level in four European mountain ranges (the Tatra Mountains, Slovakia and Poland; the Alps, Austria; the Pyrenees, Spain and France; and the Rila Mountains, Bulgaria). PO4–P sorption isotherms were determined, ranging in concentration from 0 to 6.5 mM KH2PO4 at original soil pH, and were evaluated using the Langmuir equation. PO4–P sorption maxima (Xmax) varied from 6 to 145 mmol kg−1 in the dry (105°C) fine soil fraction (<2 mm). Concentrations of Al oxohydroxides, determined as oxalate extractable aluminum (Alo), ranged between 36 and 770 mmol kg−1, and were the dominant parameter affecting the soil's ability to adsorb PO4–P. In the Tatra Mountains, Rila, and Alps, oxalate-extractable iron (Feo) was also important, while in the Pyrenees we found a significant correlation (p < 0.01) between Xmax and total organic C concentrations. The ability of Al and Fe oxohydroxides to adsorb PO4–P was higher in areas with more acidic soils (the Tatra Mountains) than in areas with higher soil pH (the Pyrenees), and in the more acidic uppermost organic soil horizons than in mineral soil horizons. A simple model based only on two basic soil characteristics (Alo and pH) explained 81 to 89% of the Xmax variability observed in individual mountain areas and 74% of the Xmax variability associated with all samples.

Published
2011

29. Modelling the effect of climate change on recovery of acidified freshwaters: Relative sensitivity of individual processes in the MAGIC model

Author

Wright, R. F., Aherne, J., Bishop, Kevin, Camarero, Lluís, Cosby, B. J., Erlandsson, M., Evans, C. D., Forsius, M., Hardekopf, David, Helliwell, R., Hruška, J., Jenkins, A., Kopáček, J., Moldan, F., Posch, M., Rogora, M., Wright, R. F., Aherne, J., Bishop, Kevin, Camarero, Lluís, Cosby, B. J., Erlandsson, M., Evans, C. D., Forsius, M., Hardekopf, David, Helliwell, R., Hruška, J., Jenkins, A., Kopáček, J., Moldan, F., Posch, M., and Rogora, M.

Abstract

The MAGIC model was used to evaluate the relative sensitivity of several possible climate-induced effects on the recovery of soil and surface water from acidification. A common protocol was used at 14 intensively studied sites in Europe and eastern North America. The results show that several of the factors are of only minor importance (increase in pCO2 in soil air and runoff, for example), several are important at only a few sites (seasalts at near-coastal sites, for example) and several are important at nearly all sites (increased concentrations of organic acids in soil solution and runoff, for example). In addition changes in forest growth and decomposition of soil organic matter are important at forested sites and sites at risk of nitrogen saturation. The trials suggest that in future modelling of recovery from acidification should take into account possible concurrent climate changes and focus specially on the climate-induced changes in organic acids and nitrogen retention.

Published
2006

30. Recovery of acidified European surface waters

Author

Wright, R. F., Larssen, T., Camarero, Lluís, Cosby, B. J., Ferrier, R. C., Helliwell, R., Forsius, M., Jenkins, A., Kopáček, J., Majer, V., Moldan, F., Posch, M., Rogora, M., Schopp, W., Wright, R. F., Larssen, T., Camarero, Lluís, Cosby, B. J., Ferrier, R. C., Helliwell, R., Forsius, M., Jenkins, A., Kopáček, J., Majer, V., Moldan, F., Posch, M., Rogora, M., and Schopp, W.

Published
2005

31. Acidification in European mountain lake districts: a regional assessment of critical load exceedance.

Author

Curtis, C. J., Botev, I., Camarero, Lluís, Catalán, Jordi, Cogalniceanu, D., Hughes, M., Kernan, M., Kopáček, J., Korhola, R., Psenner, Roland, Rogora, M., Stuchlík, Evzen, Veronesi, M., Wright, R. F., Curtis, C. J., Botev, I., Camarero, Lluís, Catalán, Jordi, Cogalniceanu, D., Hughes, M., Kernan, M., Kopáček, J., Korhola, R., Psenner, Roland, Rogora, M., Stuchlík, Evzen, Veronesi, M., and Wright, R. F.

Abstract

High mountain lakes are sensitive to environmental change and the effects of air pollution and lake acidification have been recorded in many countries. The EU funded EMERGE programme included a pan-European assessment of the extent of acidification in mountain lakes located above the tree-line. A static critical loads model, the First-order Acidity Balance (FAB) model, was used to assess (1) the extent of critical load exceedance in 300 lakes in nine European lake districts and (2) the relative importance of sulphur and nitrogen deposition in contributing to acidification. The regional sensitivity of FAB to the choice of critical acid neutralising capacity (ANC: 0 or 20 meq L–1) was explored. With a critical ANC value of 0 meq L–1 only four lake districts had sites showing exceedance of critical loads; Piedmont Aquat. Sci. 67 (2005) 237–251 1015-1621/05/030237-15 DOI 10.1007/s00027-005-0742-0 © EAWAG, Dübendorf, 2005 Aquatic Sciences Ticino, the Pyrenees, the Retezat Mountains and the Tatras. When a more stringent critical ANC of 20 meq L–1 was used, all nine lake districts showed critical load exceedance in one or more lakes. For two lake districts, the Retezat Mountains of Romania and the Rila Mountains of Bulgaria, critical load exceedance is recorded here for the first time. Nitrogen is a more important agent of acidification in some areas such as the Pyrenees and Piedmont Ticino, and its relative importance is likely to increase elsewhere as pan-European measures to reduce sulphur deposition continue to take effect. Given the coarse scale deposition data used and potentially underestimated loads at high altitudes, the extent of the acidification problem may be under-represented here.

Published
2005

41. Predicting long-term recovery of a strongly acidified stream using MAGIC and climate models (Litavka, Czech Republic).

Author

Hardekopf, D. W., Horecký, J., Kopáček, J., and Stuchlík, E.

Abstract

Two branches forming the headwaters of a stream in the Czech Republic were studied. Both streams have similar catchment characteristics and historical deposition; however one is rain-fed and strongly affected by acid atmospheric deposition, the other springfed and only moderately acidified. The MAGIC model was used to reconstruct past stream water and soil chemistry of the rain-fed branch, and predict future recovery up to 2050 under current proposed emissions levels. A future increase in air temperature calculated by a regional climate model was then used to derive climate-related scenarios to test possible factors affecting chemical recovery up to 2100. Macroinvertebrates were sampled from both branches, and differences in stream chemistry were reflected in the community structures. According to modelled forecasts, recovery of the rain-fed branch will be gradual and limited, and continued high levels of sulphate release from the soils will continue to dominate stream water chemistry, while scenarios related to a predicted increase temperature will have little impact. The likelihood of colonization of species from the spring-fed branch was evaluated considering the predicted extent of chemical recovery. The results suggest that the possibility of colonization of species from the spring-fed branch to the rain-fed will be limited to only the acid-tolerant stonefly, caddisfly and dipteran taxa in the modelled period. [ABSTRACT FROM AUTHOR]

Published
2007
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46. The concentration of organic nitrogen in mountain lakes is increasing as a result of reduced acid deposition and climate change.

Author

Kopáček J, Brahney J, Kaňa J, Kopáček M, Porcal P, and Stuchlík E

Abstract

The ionic and nutrient composition of mountain lakes recovering from atmospheric acidification is increasingly influenced by climate change (increasing air temperature and frequency of heavy rainfall events). We investigated the evolution of organic nitrogen (ON), dissolved organic carbon (DOC) and phosphorus (P) concentrations in alpine lakes in the Tatra Mountains (Central Europe) between 1993 and 2023, resulting from changes in climate and the ionic composition of atmospheric deposition. Our results suggest that the decreasing acidity of precipitation and the climatically induced increasing frequency of heavy rainfall events and air temperatures fluctuating around the freezing point have the potential to increase ON concentrations in alpine lakes despite decreasing deposition of inorganic N. The increasing ON involves its allochthonous and autochthonous sources: (1) increased co-export of ON with DOC from soils in dissolved organic matter due to less acidic precipitation and more frequent heavy rainfall events and (2) increased in-lake primary productivity (chlorophyll a) associated with higher P availability. Based on our previous studies, we hypothesize that P availability has increased due to (i) reduced adsorption of phosphate in precipitation to the metal hydroxides in the soil-adsorption complex as a result of increasing pH in precipitation and soil water and (ii) increased P production by weathering due to climate-induced increased mechanical erosion of rocks in unstable scree areas. The extent of these changes was related to the percentage cover of scree areas and meadow soils in the lake catchments. In addition, our results suggest that ON (besides chlorophyll a) may be a more sensitive indicator of increasing productivity of oligotrophic alpine lakes under changing air pollution and climate than generally low P concentrations and their poorly detectable trends., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Published
2024
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47. Cold mountain stream chironomids (Diptera) of the genus Diamesa indicate both historical and recent climate change.

Author

Dočkalová K, Stuchlík E, Hamerlík L, Bitušík P, Turek J, Svitok M, Novikmec M, Lackner R, Dvorak M, Kopáček J, Tátosová J, Camarero L, Füreder L, and Vondrák D

Subjects
Animals, Cold Temperature, Animal Distribution, Chironomidae physiology, Climate Change, Rivers
Abstract

Chironomids of the genus Diamesa (Meigen, 1835, Diptera: Chironomidae) inhabit cold, oxygen-rich running waters. We have investigated the presence of Diamesa and other freshwater macroinvertebrates at 22 stream sampling sites in 3 European high mountain regions (the Central Pyrenees, the Ötztal Alps, and the Tatra Mountains) to establish suitable temperature conditions for Diamesa dominance. It has been generally accepted that their high abundance was linked to the presence of glaciers; however, we have shown that in the Tatra Mountains, where there are no glaciers, the conditions for the dominance of Diamesa species are created due to permanent snowfields, the geographical orientation of the valley and shading by the surrounding high peaks. The historical connection of Diamesa to glaciers was investigated from the paleolimnological records of subfossil chironomid assemblages from the Bohemian Forest, where glaciers disappeared before or during the Late Glacial period. As expected, water temperature seems to be the main driver of Diamesa distribution, and we determined that the relative abundance of Diamesa species was significantly higher at the sites with a mean July water temperature below 6.5 °C. The Diamesa-dominated stream communities seems to be endangered due to ongoing climate warming and this assumption is supported by our paleolimnological results from the Bohemian Forest lakes, where Diamesa has disappeared due to warming of lake inflows at the beginning of the Holocene. These findings strengthen the former suggestions that some Diamesa species could be used as an indicator for tracking recent environmental changes in vulnerable ecosystems of cold mountain streams., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Published
2024
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48. Environmental gradients and optimal fixation time revealed with DNA metabarcoding of benthic sample fixative.

Author

Vargovčík O, Čiamporová-Zaťovičová Z, Beracko P, Kopáček J, Macko P, Tuhrinová K, and Čiampor F Jr

Subjects
Animals, Ecosystem, Invertebrates genetics, Invertebrates classification, DNA genetics, DNA isolation & purification, DNA analysis, DNA Barcoding, Taxonomic methods, Lakes, Biodiversity
Abstract

Assessments of biodiversity and ecosystem status can benefit from DNA metabarcoding as a means to streamline sample processing and specimen identification. Moreover, processing the fixation medium instead of the precious material introduces straightforward protocols that allow subsequent focus on certain organisms detected among the preserved specimens. In this study, we present a proof of concept via the analysis of freshwater invertebrate samples from the Tatra Mountain lakes (Slovakia). Besides highlighting a match between the lake-specific environmental conditions and the results of our fixative DNA metabarcoding, we observed an option to fine-tune the fixation time: to prefer two weeks over a day or a month. This effect emerged from the presence/absence of individual taxa rather than from coarse per-sample records of taxonomic richness, demonstrating that metabarcoding studies-and efforts to optimize their protocols-can use the robust metrics to explore even subtle trends. We also provide evidence that fixative DNA might better capture large freshwater species than terrestrial or meiofauna., (© 2024. The Author(s).)

Published
2024
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49. Carbon and nutrient pools and fluxes in unmanaged mountain Norway spruce forests, and losses after natural tree dieback.

Author

Kopáček J, Bače R, Choma M, Hejzlar J, Kaňa J, Oulehle F, Porcal P, Svoboda M, and Tahovská K

Abstract

Forest areas infected by insects are increasing in Europe and North America due to accelerating climate change. A 2000-2020 mass budget study on major elements (C, N, P, Ca, Mg, K) in the atmosphere-plant-soil-water systems of two unmanaged catchments enabled us to evaluate changes in pools and fluxes related to tree dieback and long-term accumulation/losses during the post-glacial period. A bark-beetle outbreak killed >75 % of all trees in a mature mountain spruce forest in one catchment and all dead biomass was left on site. A similar forest in a nearby catchment was only marginally affected. We observed that: (1) the long-term (millennial) C and N accumulation in soils averaged 10-22 and 0.5-1.1 kg ha -1  yr -1 , respectively, while losses of Ca, Mg, and K from soils ranged from 0.1 to 2.6 kg ha -1  yr -1 . (2) Only <0.8 % and <1.5 % of the respective total C and N fluxes entering the soil annually from vegetation were permanently stored in soils. (3) The post-disturbance decomposition of dead tree biomass reduced vegetation element pools from 27 % (C) to 73 % (P) between 2004 and 2019. (4) Tree dieback decreased net atmospheric element inputs to the impacted catchment, and increased the leaching of all elements and gaseous losses of C (∼2.3 t ha -1  yr -1 ) and N (∼14 kg ha -1  yr -1 ). The disturbed catchment became a net C source, but ∼50 % of the N released from dead biomass accumulated in soils. (5) Despite the severe forest disturbance, the dissolved losses of Ca and Mg represented 52-58 % of their leaching from intact stands during the peaking atmospheric acidification from 1970 to 1990. (6) Disturbance-related net leaching of P, Ca, Mg, and K were 4, 69, 16, and 114 kg ha -1 , respectively, which represented 7-38 % of the losses potentially related to sanitary logging and subsequent removal of the aboveground tree biomass., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Published
2023
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50. Accelerated recovery of lake macroinvertebrates in the third decade since the reversal of acidification.

Author

Petruželová J, Bojková J, Sychra J, de Donnová S, Vrba J, Polášková V, Seifert L, Šorfová V, and Kopáček J

Subjects
Animals, Ecosystem, Fishes, Water, Hydrogen-Ion Concentration, Invertebrates, Lakes chemistry, Environmental Monitoring methods
Abstract

Chemical reversal from acidification has been progressing in European freshwaters since the late 1980s, responding to successful control of atmospheric pollution by acidifying emissions. However, biological recovery is often delayed after improvements in water composition. We studied macroinvertebrate recovery from acidification in eight glacial lakes in the Bohemian Forest (central Europe) between 1999 and 2019. The chemical composition of these lakes reflects a complex of environmental changes, dominated by a very steep decline in acid deposition and, currently, by elevated nutrient leaching following climate-induced tree dieback within their catchments. Temporal trends in species richness, abundance, species traits and community composition were evaluated with regard to water chemistry, littoral habitat properties and fish colonisation. The results showed accelerated recovery of macroinvertebrates following two decades of gradual improvement in water composition and slowly progressing biological rehabilitation. We observed a significant increase in macroinvertebrate species richness and abundance, coupled with distinct changes in community composition, the extent of changes varying between lakes, reflecting different littoral habitat properties (vegetated vs. stony) and water chemistry. Overall, the communities shifted toward more specialised (grazers, filterers, and phytophilous species) and acid-tolerant taxa at the expense of detritivorous, eurytopic and acid-resistant taxa. Where fish reappeared, open-water taxa declined greatly. Compositional changes were likely driven by the combined effects of water chemistry reversal, rehabilitation of habitat conditions and fish colonisation. Despite favourable trends, communities in recovering lakes still lack several biotic elements, particularly less vagile, acid-sensitive taxa and specialised herbivores known from the regional species pool. It is expected that future progress in lake recovery will be further promoted or inhibited by stochastic colonisation or disturbance events., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Published
2023
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