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Bede-Fazekas A.,Corvinus University of Budapest | Horvath L.,Corvinus University of Budapest | Trajer A.J.,University of Pannonia | Trajer A.J.,MTA PE Limnoecology Research Group | Gregorics T.,Eotvos Lorand University
Applied Artificial Intelligence | Year: 2015

This article is about the development and application of an ESRI ArcGIS tool that implements a multilayer, feed-forward artificial neural network (ANN) to study the climate envelopes of species. The supervised learning is achieved by a backpropagation algorithm. Based on the distribution and the grids of the climate (and edaphic data) of the reference and future periods, the tool predicts the future potential distribution of the studied species. The trained network can be saved and loaded. A modeling result based on the distribution of European larch (Larix decidua Mill.) is presented as a case study. Copyright © 2015 Taylor & Francis Group, LLC. Source

Trajer A.,University of Pannonia | Trajer A.,MTA PE Limnoecology Research Group | Mlinarik L.,H+ Technology | Juhasz P.,H+ Technology | Bede-Fazekas A.,Corvinus University of Budapest
Applied Ecology and Environmental Research | Year: 2014

Leishmaniasis is one of the most important emerging vector-borne diseases in Western Eurasia. Although winter minimum temperatures limit the present geographical distribution of the vector Phlebotomus species, the heat island effect of the cities and the anthropogenic heat emission together may provide the appropriate environment for the overwintering of sand flies. We studied the climate tempering effect of thermal bridges and the heat island effect in Budapest, Hungary. Thermal imaging was used to measure the heat surplus of heat bridges. The winter heat island effect of the city was evaluated by numerical analysis of the measurements of the Aqua sensor of satellite Terra. We found that the surface temperature of thermal bridges can be at least 3-7 °C higher than the surrounding environment. The heat emission of thermal bridges and the urban heat island effect together can cause at least 10 °C higher minimum ambient temperature in winter nights than the minimum temperature of the peri-urban areas. This milder micro-climate of the built environment can enable the potential overwintering of some important European Phlebotomus species. The anthropogenic heat emission of big cities may explain the observed isolated northward populations of Phlebotomus ariasi in Paris and Phlebotomus neglectus in the agglomeration of Budapest. © 2014, ALÖKI Kft., Budapest, Hungary. Source

Yang Y.,Uppsala University | Pettersson K.,Uppsala University | Padisak J.,University of Pannonia | Padisak J.,MTA PE Limnoecology Research Group
Hydrobiologia | Year: 2015

The seasonal development of phytoplankton is a sequence of consecutive events with waxes and wanes of biomass and compositional shifts. This study analyzed 16 years data in Lake Erken, Sweden and revealed four baselines of phytoplankton succession with their underlying drivers. Results showed that there were two diatom-dominated phases annually. The vernal community was dominated by centric diatoms larger than 15 µm (functional groups B and C) which were fast-growing diatoms being highly efficient in the use of nutrients. The autumn community was comprised mainly meroplanktonic mixing-dependent Aulacoseira granulata and Fragilaria sp. (MP and P) or/and large centric diatoms (B). Between the two mixing-phases with diatoms, a Gloeotrichia echinulata (H2) bloom occurred due to its preference for a stratified water column with elevated water temperatures and high light availability. The summer stratification in Lake Erken was weak and short, thus, favoring meroplanktonic diatoms to peak once the lake turned over in early autumn. Lake Erken represents an intermediate case between a highly mixed polymictic lake and a lake with strong summer stratification, where the observed stratification patterns allowed the development of an autumn diatom phase similar, by extent, to the vernal one and mainly dominated by meroplanktonic diatoms. © 2015 Springer International Publishing Switzerland Source

Hu R.,Jinan University | Li Q.,Guizhou Normal University | Han B.-P.,Jinan University | Naselli-Flores L.,University of Palermo | And 3 more authors.
Hydrobiologia | Year: 2015

Water quality improvement and suppression of cyanobacterial blooms were planned in a eutrophic reservoir in southern China through ecological engineering measures from 2006 to 2011. This consisted in (i) a hydraulic resetting of inflows and outflows to increase the distance between inlet and outlet and the water residence time in the reservoir, and in (ii) the installation of floating frames hosting wetland vegetation to promote an alteration in phytoplankton composition. The environmental changes were therefore followed through the analysis of biotic responses in phytoplankton assemblages. Ecological engineering was effective in reducing phytoplankton total biomass, in re-establishing more diversified phytoplankton assemblages and in avoiding cyanobacterial blooms. These changes may be considered as an improvement of the reservoir water quality. However, trophic state parameters and the dynamics of dominant species were not sensitive enough in describing the environmental changes that had occurred when the eco-engineering measures were implemented. These were more effectively tracked by the dynamics followed by phytoplankton Morpho-Functional-Groups and by their classification based on Competitors, Stress tolerants and Ruderals strategies. Although providing immediate positive effects, the eco-engineering was temporally limited, highlighting the importance of constant management in the context of long-term oriented remediation techniques. © 2015 Springer International Publishing Switzerland Source

Naselli-Flores L.,University of Palermo | Padisak J.,University of Pannonia | Padisak J.,MTA PE Limnoecology Research Group
Hydrobiologia | Year: 2015

The selected theme of the 17th Workshop of the International Association for Phytoplankton Taxonomy and Ecology (IAP), “Biogeography and Spatial Patterns of Biodiversity of Freshwater Phytoplankton,” offered the opportunity to explore one neglected aspect of phytoplankton ecology: the distribution of species in the geographic space. This paper summarizes the outcomes of 20 selected contributions among those presented at the workshop. The articles report the results from studies carried out in five continents (only Oceania is not represented) and on a wide array of aquatic ecosystems (deep and shallow natural lakes, man-made lakes, temporary and permanent ponds, rivers). The topics analyzed by the contributors are related to Island Biogeography paradigms, dispersal vectors, survival strategies, environmental filters, dispersal distances, vertical and horizontal spatial variability of phytoplankton between and within water bodies, and of course, invasive algae. The overall analysis of the results presented clearly demonstrates that, as for many others organisms, there are “rules” governing freshwater phytoplankton spatial patterns and that these organisms also have a true biogeography, as nowadays is quite evident for several other groups in the same range of size. We can definitively conclude that the statement “Everything is everywhere” is obsolete, even though human activities tend to homogenize species distribution in the biosphere. © 2015 Springer International Publishing Switzerland Source

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