• Baxa, M., Musil, M., Kummel, M., Hanzlík, P., Tesařová, B., & Pechar, L. (2021). Dissolved oxygen deficits in a shallow eutrophic aquatic ecosystem (fishpond) – sediment oxygen demand and water column respiration alternately drive the oxygen regime.

Biological processes tend to dominate the oxygen regime of productive waters. However, in shallow aquatic ecosystems, it is unclear whether the oxygen regime is driven by oxygen production and consumption in the water column or by sediment oxygen demand (SOD). In managed eutrophic ecosystems, this question is especially important in the context of extreme daily oscillations of dissolved oxygen (DO) that could breach physiological limits of heterotrophic aerobic organisms. High-frequency measurement of DO, temperature, global radiation (Gl.Rad.), and pH in a 0.6 m deep, 22 ha eutrophic fishpond Rod (Czech Republic) shows that the oxygen regime depended on the ecosystem state. Over the clearwater period in the early season, the DO level reflected ecosystem heterotrophy with relatively low daily DO oscillations. However, during the summer phytoplankton bloom, the fishpond was primarily autotrophic with extreme DO fluctuation. During late summer, a collapse of the phytoplankton bloom and an associated shift towards heterotrophy and DO deficit frequently occur. In-situ mesocosm experiments in Rod fishpond were conducted throughout 2018 and 2019 growing seasons, to address the importance of SOD to the oxygen regime. We enclosed the water column in transparent and opaque/dark plastic cylinders open or closed to the sediment. The results show that the proportional contribution of SOD to total respiration decreased from 70 to 90% at low phytoplankton biomass (expressed as Chlorophyll-a (Chl-a) concentration) to approximately 10% at phytoplankton bloom. At night, the difference between the oxygen consumption in the cylinders with or without sediment was statistically significant, when the concentration of Chl-a was <100 μg·L-1. On the contrary, the difference was not significant when the concentration of Chl-a was >100 μg·L-1. This revealed that the impact of SOD is negligible at high phytoplankton biomass. 

Shallow aquatic ekosystém; Dissolved oxygen; Sediment oxygen demand; Eutrophic water; Fishpond; Oxygen deficit

• Hesslerová, P., Pokorný, J., Huryna, H., Seják, J., & Jirka, V. (2021). The impacts of greenery on urban climate and the options for use of thermal data in urban areas Progress in Planning.

Urban greenery substantially influences the distribution of solar energy in urban areas and thus plays an irreplaceable role in creating local climate. This paper introduces the principles of urban vegetation functioning as a perfect air conditioning system that efficiently cools the environment and balances temperatures through evapotranspiration. It is based on the basic physics of energy transformation and known physiological processes of plants. We demonstrate the possibilities of quantification of the air conditioning role of vegetation in energy units, including the assessment and monetary quantification of ecosystem services and examples of different types of thermal data for assessing the urban environment and climate. We offer the possibility of implementing this approach to spatial planning.

Solar energy; Evapotranspiration Ecosystem services; Surface temperature; Air-conditioning; Trees

• Baxa, M., Šulcová, J., Kröpfelová, L., Pokorný, J., & Potužák, J. (2019). The quality of sediment in shallow water bodies – Long-term screening of sediment in Czech Republic. A new perspective of nutrients and organic matter recycling in agricultural landscapes. Ecological Engineering, 127, 151-159. doi:https://doi.org/10.1016/j.ecoleng.2018.11.009

The results of long-term screening of sediments from the Czech Republic from 2011 to 2017 are presented, more than 80% of the samples of which were taken from fishponds. The total sediment volume of Czech Republic fishponds is estimated to be 197 mil. m³. Quality of the sediment is impacted by numerous factors. Sediment may be used for land application, etc., as long as it abides with legislation limits. All results from our database, containing some 200 sites, have been compared with the Decree regulating the conditions for the application of sediments on agricultural land.

We have evaluated toxic metals (As, Pb, Zn, Cu, Hg, Cd), organic pollutants (C10–C40, BTEX, PAH, PCB, DDT) and nutrient volume. The assessment of results reveal the average concentrations of evaluated metals to have the following ranking: Zn > Cu > Pb > As > Cd > Hg. The most frequent excesses of the limit listed in Decree No. 257/2009 Sb. were reported for cadmium (21 sites, i.e. 13.2%). In the case of organic pollutants, the worst pollutant exceeded the limits for 7.2% of sites. DDT volume values were all below the threshold. The ratio between available nutrients and overall nutrient volume was: 0.5% P; 1.3% N; 48.1% Na; 20.4% Mg; 5.8% K; and 65.7% Ca.

Water ekosystém; Fishpond sediment; Toxic metals; Organic pollutants; Nutrients; Agricultural land

• Vlček, P., Zavadil, V., & Gvoždík, V. (2020). The need for transboundary faunistics and conservation: first record of the Natterjack Toad (Epidalea calamita) in Czech Silesia, northeastern Czech Republic. Amphibian & Reptile Conservation, 14(3), 62-69.

The Natterjack Toad (Epidalea calamita) has been severely declining in the northern and eastern parts of its range in past decades. An immense population decline has been recorded in the Czech Republic, the southeastern edge of the species range. Contrary to the majority of published distribution range maps of the Natterjack Toad, it is present only in the western part of the Czech Republic (Bohemia), scattered among mostly isolated populations. A new, relatively distant population was recently discovered in the northeastern part of the country, in Czech Silesia. The genetic analysis presented here demonstrates that the new population belongs to the evolutionary lineage that is widely distributed in the northeastern part of the species range. Thus, this population is not a possible exotic introduction, but probably represents a natural extension of Natterjack Toad populations from Poland to the south. We urge conservation actions to be taken immediately to support this unique population, which is presently inhabiting a dump site. We further emphasize the necessity of considering distribution records on both sides of state borderlines when faunistic research is conducted in borderlands.

Amphibians, anthropogenic habitat, Bufonidae, Central Europe, distribution, edge populations, geographic range limit, phylogeography, range extension

Ke stažení

• Hesslerová, P., Pokorný, J., Huryna, H., & Harper, D. (2019). Wetlands and Forests Regulate Climate via Evapotranspiration. In S. An & J. T. A. Verhoeven (Eds.), Wetlands: Ecosystem Services, Restoration and Wise Use (pp. 63-93). Cham: Springer International Publishing

The role of wetlands and forests in climate and climate change is usually considered as a part of their functions as source or sink of greenhouse gases. However, the permanent vegetation in these systems is an active factor that, through the process of evapotranspiration, directly influences climate as well. Wet vegetation transforms solar radiation into the latent heat of water vapour. Evapotranspiration is a powerful tool that has, due to the phase change of water, a double air-conditioning effect in the landscape. In addition, it reduces thermal gradients, mitigates temperature extremes and closes water and mass cycles. Evapotranspiration-condensation processes slow down where there is a lack of water and permanent vegetation. Solar radiation is then transformed into sensible heat. The overheated surfaces warm the adjacent air layer. Warm air rises turbulently upwards and is capable of absorbing higher amounts of water vapour, which is then transmitted to higher levels of the atmosphere where condensation occurs. These processes significantly dry out the landscape. The Intergovernmental Panel on Climate Change (IPCC) reports, however, do not take into account this direct effect of water and vegetation on climate. This chapter explains the direct function of wetlands and the air-conditioning effect of evapotranspiration, which is also illustrated with thermal ground images. The role of forest and wetlands in transport of water from ocean into continents in terms of a biotic pump is discussed on the basis of the literature.

Solar energy; Latent heat flux; Surface temperature; Thermal images; Climate change; Landscape restoration 

• Craft, C., Vymazal, J., & Kröpfelová, L. (2018). Carbon sequestration and nutrient accumulation in floodplain and depressional wetlands. Ecological Engineering, 114, 137-145.

We measured soil organic carbon (C) sequestration and nutrient (nitrogen-N, phosphorus- P) burial in Czech and Midwest U.S. freshwater floodplain and depressional wetlands to evaluate how landscape position and agricultural land use intensity affects C, N, and P retention. Land use in the South Bohemia of the Czech Republic is dominated by forest and pasture, whereas in the Midwest U.S., land use is dominated by row crop agriculture. Cs-137 and ²¹⁰Pb dating of soil cores revealed comparable rates of soil accretion among wetland types, ranging from 0.5 mm/yr in a Czech floodplain wetland to 2.3 mm/yr in a U.S. depressional wetland. Carbon sequestration and N & P burial did not differ among floodplain (47 + 14 g C/m²/yr, 3.7 + 1 g N/m²/yr, 0.47 + 0.16 g P/m²/yr) and depressional wetlands (50 + 19 g/m²/yr, 3.6 + 1.3 g N/m²/yr, 0.51 + 0.14 g P/m²/yr). However, sediment deposition in Czech floodplain and depressional wetlands was only 10–50% (150–340 g/m²/yr) of rates measured in U.S. wetlands (650–1460 g/m²/yr). Our results suggest that, in agricultural landscapes, land use intensity rather than landscape position – floodplain versus depression – drives wetland C sequestration and nutrient retention through increased sediment deposition.

Geomorphic; Landscape position; Nutrients; Sediment; Carbon; Nitrogen; Phosphorus; Land use; Agriculture; Erosion

• Hynek, R., Kuckova, S., Cejnar, P., Junková, P., Přikryl, I., & Říhová Ambrožová, J. (2018). Identification of freshwater zooplankton species using protein profiling and principal component analysis. Limnology and Oceanography: Methods, 16(3), 199-204. doi:https://doi.org/10.1002/lom3.10238

Crustaceans are vital components of the freshwater zooplankton that link various trophic levels. Because crustaceans, particularly cladocerans of the Daphnia genus, are sensitive to environmental changes, they can serve as indicators of environmental fluctuations. Therefore, it is highly desirable to have a fast and reliable method for the identification of individual Daphnia species. In this study, we demonstrated the ability of protein profiling to distinguish between freshwater zooplankton species. Individual specimens were morphologically identified before being analyzed by proteomic fingerprinting using matrix‐assisted laser desorption/ionization time of flight mass spectrometry (MALDI‐TOF MS). The obtained mass spectra were used to create a reference library. Subsequently, the individual species were successfully identified using Biotyper software. The variability between the spectra of individual Daphnia species was verified by principal component analysis (PCA). Our results suggest that the combination of proteome fingerprinting using MALDI‐TOF MS and PCA has considerable potential as a rapid tool for the unambiguous identification of individual species of freshwater zooplankton without the need for expert morphological analysis.

Determination methods; zooplankton; principal component analysis (PCA)

• Ellison, D., Morris, C. E., Locatelli, B., Sheil, D., Cohen, J., Murdiyarso, D., . . . Sullivan, C. A. (2017). Trees, forests and water: Cool insights for a hot world. Global Environmental Change, 43, 51-61. doi:10.1016/j.gloenvcha.2017.01.002

Forest-driven water and energy cycles are poorly integrated into regional, national, continental and global decision-making on climate change adaptation, mitigation, land use and water management. This constrains humanity’s ability to protect our planet’s climate and life-sustaining functions. The substantial body of research we review reveals that forest, water and energy interactions provide the foundations for carbon storage, for cooling terrestrial surfaces and for distributing water resources. Forests and trees must be recognized as prime regulators within the water, energy and carbon cycles. If these functions are ignored, planners will be unable to assess, adapt to or mitigate the impacts of changing land cover and climate. Our call to action targets a reversal of paradigms, from a carbon-centric model to one that treats the hydrologic and climate-cooling effects of trees and forests as the first order of priority. For reasons of sustainability, carbon storage must remain a secondary, though valuable, by-product. The effects of tree cover on climate at local, regional and continental scales offer benefits that demand wider recognition. The forest- and tree-centered research insights we review and analyze provide a knowledge-base for improving plans, policies and actions. Our understanding of how trees and forests influence water, energy and carbon cycles has important implications, both for the structure of planning, management and governance institutions, as well as for how trees and forests might be used to improve sustainability, adaptation and mitigation efforts.

Forest; Water; Energy; Climate; Carbon; Reforestation; Mitigation; Adaptation; Sustainability

• Hlaváč, D., Másílko, J., Hartman, P., Bláha, M., Pechar, L., Anton-Pardo, M., & Adámek, Z. (2015). Effects of common carp (Cyprinus carpio Linnaeus, 1758) supplementary feeding with modified cereals on pond water quality and nutrient budget. Journal of Applied Ichthyology, 31(Suppl. 2), 30-37. doi:10.1111/jai.12850

This 4‐month study (10 May – 6 September 2012) evaluated the effects of supplementary feeding on common carp (Cyprinus carpio Linnaeus, 1758) growth, water quality, natural food availability and nutrient balance under different pond treatment regimes (eight rectangular earthen ponds; 0.03 ha surface area; 3‐year‐old carp). The nitrogen and phosphorus budgets were calculated as the difference between input (food, fish stocked and influent water) and output (effluent water and fish harvested). Three types of supplementary feeds were used: wheat, thermally‐treated wheat, and thermally‐treated and pressed wheat. An additional test group was provided with naturally available forage only and served as a control. The type of supplementary feed did not influence the water quality, with the exception of dissolved oxygen. No significant differences among experimental ponds were observed in zooplankton abundance. The use of modified cereals (especially thermally‐treated and pressed wheat) improved carp growth performance and resulted in lower nutrient concentrations in effluent water via improving their digestibility. Both thermally‐treated and thermally‐treated and pressed cereals improved the balance of phosphorus; hence these diets could be beneficial, not only from the fish production point of view but also as a tool to reduce the deterioration of pond water quality.

Carp production; natural food;

• Vinciková, H., Hanuš, J., & Pechar, L. (2015). Spectral reflectance is a reliable water-quality estimator for small, highly turbid wetlands. Wetlands Ecology and Management, 23(5), 933-946.

Spectral reflectance from water surfaces was measured in small (0.01–5 km2), turbid, eutrophic fishponds and mesotrophic quarry lakes in the Třeboň basin (South Bohemia, Czech Republic). A spectral scanner for direct field measurements from water surfaces and a hyperspectral airborne scanner were both used. The quarry lakes and fishponds differed in their spectral signature, which reflected the extent of their eutrophication. Their chlorophyll-a (chl-a) concentrations ranged from 2 to 455 µg/l−1. Various algorithms were tested to best fit the relationships between reflectance patterns and the water-quality parameters used—concentration of chl-a and the total amount of suspended solids. The reflectance ratios at 714 and 650 nm gave the best estimates for chl-a concentrations, and simple reflectance at near infrared wavelengths, especially at 806 nm, gave the best predictive values for total suspended solid evaluation (r 2 = 0.89). Field surface reflectance and airborne sensing measurements were well correlated; however, airborne reflectance data showed higher variability (r 2 = 0.93 and 0.86, respectively). The results support the validity of reflectance measurements, both field and airborne, as a rapid tool for evaluating water quality in many turbid and greatly disturbed, small water bodies.

Remote sensing; Water quality; Hyperspectral reflectance; Turbid inland waters; Chlorophyll; TSS

• Musil, M., Novotná, K., Potužák, J., Hůda, J., & Pechar, L. (2014). Impact of topmou2012th gudgeon (Pseudorasbora parva) on production of common carp (Cyprinus carpio) — question of natural food structure. Biologia, 69(12). doi:10.2478/s11756-014-0483-4

Four production fishponds in the Czech Republic were investigated in 2003 and 2004 during a feeding experiment on common carp (Cyprinus carpio). In 2003, topmouth gudgeon (Pseudorasbora parva) was detected in enormous amounts in all of the investigated fishponds. P. parva got into the fishponds spontaneously by water inflow from connecting channels. The objective of this paper is to describe the condition of natural food in the presence of P. parva and its subsequent effect on carp production. The estimation of the population density of P. parva achieved at least 44 kg/ha in 2003. In 2004, precautions against P. parva invasion were taken and its presence wasn?t recorded during the season. The impact of P. parva on natural food structure was described in terms of zooplankton and zoobenthos amounts and main fish production parameters. A special focus has been taken on the density of Daphnia genus and chironomid larvae, the most preferred zooplanktonic and zoobenthic groups in feed of P.arva,respectively. In 2003,P.parva suppressed the zooplankto npopulations significantly, especially large cladocerans of the Daphnia genus. Influence of P.parva on zoobenthos structureand density was not detectable. Unfavorable natural food condition in 2003 caused extremely low carp production whichfell to the mean value of 283 kg ha−1and food conversion ratio reached 3.5. On the contrary, in 2004 the mean carp production and food conversion ratio attained 634 kgha−1and 1.6, respectively. The results described harmful competitive effect of huge populations of P.parva and its surprising economic consequences. Costs per 1 kg of growth were increasedby approximately 100% in 2003 compared with results from season 2004.

Biological invasion; carp production; natural food; Pseudorasbora parva; zoobenthos; zooplankton

• Hesslerová, P., Pokorný, J., Brom, J., & Rejšková – Procházková, A. (2013). Daily dynamics of radiation surface temperature of different land cover types in a temperate cultural landscape: Consequences for the local climate. Ecological Engineering, 54, 145-154. doi:10.1016/j.ecoleng.2013.01.036

Surface temperature (T_s) is directly related to the capacity of every ecosystem to direct energy to different heat fluxes. Vegetation with a sufficient supply of water is able to cool down the surface by enhancing the latent heat flux via evapotranspiration. We chose seven types of land covers common in a temperate agricultural landscape and used a combined method of airship thermal scanning of T_s and ground measuring of thermodynamic T_a to show their T_s and T_a (air temperature) characteristics under high solar irradiance and their consequences for local climate; simultaneously we showed that this temperature difference increases with water content. A combined method of airship thermal scanning of T_s and ground measuring of thermodynamic T_a was used. The localities differed markedly in both the values and the dynamics of T_s and T_s − T_a. In the early afternoon the difference in T_s between the different land covers reached almost 20 °C. Ecosystems with non-functional or no vegetation largely resembled the asphalt surface, whereas the ecosystems covered with dense, bushy or tree vegetation showed relatively well balanced daily temperature dynamics with low temperature extremes and a slow temperature morning increase or afternoon decrease. T_s − T_a at the peaking solar irradiance ranged between −1 °C at the forest and 14–17 °C at the dry harvested meadow and the asphalt surface respectively. We highlight the importance of T_s as a measurable indicator of ecosystem and landscape functioning and outline the importance of functional vegetation for climate. Those feedbacks between vegetation, surface temperature, water and climate are crucial in the landscape management, climate change discussions and therefore for decision makers and landscape developers.

Solar energy distribution; Water; Vegetation; Climate; Airship thermal scanning

• Hesslerová, P., Chmelová, I., Pokorný, J., Šulcová, J., Kröpfelová, L., & Pechar, L. (2012). Surface temperature and hydrochemistry as indicators of land cover functions. Ecological Engineering, 49, 146-152. doi:10.1016/j.ecoleng.2012.08.029

This paper presents an integrated approach to landscape functioning assessment combining energy efficiency and hydrochemical balance studies. Energy balance is expressed by surface temperature while hydrochemical balance is illustrated by electric conductivity and selected hydrochemical parameters. Six model sub-watersheds with different land use situated in southern Bohemia were chosen to show the influence of landscape management on landscape functioning. The watersheds with higher humankind activity were shown to have both higher and more fluctuating average surface temperature as well as higher electrical conductivity in the runoff surface water. Watersheds with the predominance of forests and meadows showed opposite trends in the monitored parameters. Our results show that sustainable landscape management leads to lower temperature extremes and consequently to low matter and water losses. Large improvements of energy and matter balance can be achieved by restoration of permanent vegetation and/or effective water retention and accumulation.

Solar energy distribution;, Landsat TM; Water electrical conductivity; Catchment; Sustainable landscape management

• Pacini, N., Pechar, L., & Harper, D. M. (2019). Chemical Determinands of Freshwater Ecosystem Functioning. In Freshwater Ecology and Conservation: Approaches and Techniques (Vol. Library od Congress Conttrol Number: 2018948522, pp. 89). Oxford: Oxford University Press.

Chemical equilibria in surface waters stem from complex interactions between physical background and living components of ecosystems. Catchments differ in geological background, climate, and land use; their run-off bears a distinctive chemical ‘fingerprint’. This chapter illustrates how the monitoring of standard parameters, such as oxygen, pH, conductivity, major ions, nutrients, and carbon, can lead to an interpretation of key aspects of the functioning of major ecosystem processes and how chemical constituents may affect the distribution of aquatic organisms. This requires understanding principles that underlie available measurement techniques and it demands a certain familiarity with the intrinsic variability of parameter values and of their chemical interaction. It is not required that field scientists be able to conduct detailed chemical assessments, but all should be able to collect samples yielding high-quality data. Therefore, detailed advice on chemical monitoring practice is provided, including sample collection, filtering, sample processing, and is discussed with the context of several case studies.