Baxa, M., Šulcová, J., Kröpfelová, L., Pokorný, J., & Potužák, J.
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.
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.
Hesslerová, P., Pokorný, J., Huryna, H., & Harper, D.
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.
Vlček, P., Zavadil, V., & Gvoždík, V.
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.
Baxa, M., Musil, M., Kummel, M., Hanzlík, P., Tesařová, B., & Pechar, L.
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.
Hesslerová, P., Pokorný, J., Huryna, H., Seják, J., & Jirka, V.
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.