Peer teaching as support for the use of concept maps in independent online learning

S ciljem kognitivnoaktivnog uključivanja studenata, u proces poučavanja studentima koji su na početku visokoškolskog obrazovanja pružena je vršnjačka podrška u stjecanju predmetno specifičnog znanja konceptualnom mapom. Istraživanje se provelo akademske 2021./2022. i 2022./2023. godine s ukupno pedeset studenata prijediplomskog sveučilišnog studija Biologija Odjela za biologiju Sveučilišta u Osijeku. Studenti (budući učitelji/nastavnici Prirode, Biologije i Kemije), koji su bili u ulozi onih koji poučavaju, osmisli su i proveli u prvoj fazi istraživanja nastavu u kojoj su se izmjenjivale različite studentske aktivnosti, a koje ujedno podržavaju uočavanje i izdvajanje ključnih pojmova i veza među njima što je neophodno za dostizanje znanja na višim kognitivnim razinama. Istu nastavu su potom programirali te na taj način prilagodili online učenju. U drugoj fazi istraživanja sa studentima se provela inicijalna pisana provjera znanja te su potom upućeni na samostalno online učenje nakon kojeg je uslijedila završna pisana provjera. Usporedbom inicijalne i završne pisane provjere znanja utvrdila se učinkovitost vršnjačke podrške tijekom samostalnog online učenja. Rezultati ukazuju da su studenti postigli bolju riješenost u pitanjima svih testiranih kognitivnih razina u završnoj pisanoj provjeri znanja u odnosu na inicijalnu.With the goal of cognitively active involvement of students in the teaching process, students who are at the beginning of higher education were provided with peer support in acquiring subject-specific knowledge using a concept map. The research was conducted in the academic years 2021/2022 and 2022/2023 with a total of fifty students of the Undergraduate University Study of Biology at the Department of Biology, University of Osijek. During the first phase of the research, students (future teachers of Nature, Biology, and Chemistry) who were in the role of those who teach designed and conducted a lesson in which different student activities alternated. At the same time supported the observation and separation of key concepts and connections between them, which is necessary for reaching knowledge at higher cognitive levels. Next, they programmed the same lesson and adapted it to online learning. In the second phase of the research, an initial written test of knowledge was conducted. Afterwards, the students were directed to independent online learning, which was followed by a final written test. By comparing the initial and final written tests, the effectiveness of peer support during independent online learning was determined. The results show that the students achieved a better score in the questions of all tested cognitive levels in the final written test of knowledge compared to the initial one

Rasprostranjenost pajasena (Ailanthus altissima (Mill.) Swingle), invazivne biljne vrste, na području grada Osijeka

The research on the tree of heaven (Ailanthus altissima (Mill.) Swingle) distribution within the Osijek city area was carried out in the summer period of 2017. In total of 589 individuals of the tree of heaven on 130 locations were recorded. The trees grew individually or in groups, mostly on abandoned places, and were rarely found in well-maintained areas. In the vicinity of the tree of heaven, mostly perennial herbaceous weeds were found. These plants thrive in different types of habitats. In order to prevent the uncontrolled spread of this invasive plant in the urban environment, it is necessary to continuously monitor and timely remove the tree of heaven individuals. Moreover, it is important to continuously educate the general public about the adverse impact of this species on the environment and biological diversity.Istraživanje prisutnosti pajasena (Ailanthus altissima (Mill.) Swingle) na području grada Osijeka provedeno je u ljetnom razdoblju 2017. godine. Na 130 lokaliteta zabilježeno je ukupno 589 jedinki stabala pajasena. Pajasen je rastao pojedinačno ili u skupinama, uglavnom na napuštenim područjima, dok je na uređenim i održavanim površinama bio rijetko prisutan. U neposrednoj blizini pajasena zabilježene su korovne, višegodišnje zeljaste biljke koje uspijevaju na različitim tipovima staništa. U svrhu sprječavanja nekontroliranog širenja ove invazivne biljke u gradskoj sredini potrebno je kontinuirano provoditi praćenje i pravovremeno uklanjanje pajasena, kao i kontinuiranu edukaciju šire javnosti o nepovoljnom utjecaju ove vrste na okoliš i biološku raznolikost

Early spring flora of the Sub-Pannonic steppic grassland (NATURA 2000 site) in Bilje, northeast Croatia

The diversity of early spring vascular flora was studied in the Sub- pannonic steppic grassland in the village of Bilje, north eastern Croatia. In all, 109 plant taxa within 35 families were found. The highest number of taxa belongs to the families Poaceae, Fabaceae, Asteraceae, Caryophyllaceae, Lamiaceae and Rosaceae. Specific habitat conditions, characterized by moderately wet and moderately acidic soil with intermediate fertility and the effects of the continental climate favour the development of different plant life forms. Out of the total recorded plant taxa, hemicryptophytes make up 59.6%, followed by therophytes (22.0%) and geophytes (13.8%). Chorological analysis shows that the most numerous are plants of Eurasian (33.9%), Pontic-Central-Asian (21.1%) and Central European (21.1%) floral elements. According to their status in the Red List, three critically endangered (CR), one vulnerable (VU) and three nearly threatened (NT) plant species were found. Altogether, the steppe-like grassland in Bilje is a unique habitat rich in valuable plants of the Croatian flora, including the critically endangered Doronicum hungaricum, therefore it is of great importance to preserve it. Important management tools include mowing and controlling the spreading of cultivated and invasive plant species

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.Peer reviewe

Periphytic algae colonization driven by variable environmental components in a temperate floodplain lake

The colonization of periphytic algae in a temperate floodplain was studied in Lake Sakadaš, a part of a fluvial floodplain along the Danube River. An in situ investigation, using artificial substrata, was started after extremely high spring flooding and was carried out during long-lasting summer floods (July–August 2010). The physical and chemical environment was variable and large stands of metaphyton, submersed and floating macrophytes were spread along the lake. The periphyton development was initiated on the first day of exposition and algal abundance increased exponentially till day 27. Directional changes in the relative abundance of algal species, shown by the results of the non-metric multidimensional scaling, indicate a pattern of short-term sequences in algal colonization. The initial attachment of planktonic cyanobacteria and unicellular diatoms (initial phase, days 1–3) to the biofilm matrix was followed by the development of the filamentous chlorophytes, Cladophora glomerata and Oedogonium spp. (intermediate phase, days 6–15) and then by stalk-forming diatoms particularly Gomphonema spp. (late phase, days 18–33). According to the redundancy analyses, water temperature and oscillations of Danube water level that define the flooding pattern had the most significant influence on algal colonization. Flood-induced spreading of metaphyton firstly supported the rapid progress of algal colonization towards a climax community, while later, metaphyton together with macrophytes disrupted algal community by increasing the mechanical injuries, shading and grazing pressure. Consequently, algal abundance and community structure were returned to the intermediate phase of colonization

The influence of extreme floods from the River Danube in 2006 on phytoplankton communities in a floodplain lake: Shift to a clear state

AbstractThe influence of extreme floods from the River Danube in 2006 on the species composition and vertical distributions of phytoplankton was studied in a shallow floodplain lake, Lake Sakadaš (Kopački Rit Nature Park, Croatia) which in the last few decades was in a turbid state characterised by high phytoplankton concentrations. As a consequence of extremely high floods, the whole floodplain area (approximately 16km2) became one lentic habitat with well developed macrophyte vegetation. Seasonal dynamics of chlorophyll a (Chl a) concentration in the lake had a characteristic pattern for the shallow lakes with dense macrophyte vegetation. Extremely low mean phytoplankton abundance and biomass were found in the conditions of very high nutrient concentrations. Dominant phytoplankton species were diatoms and chlorococcal green algae from the functional groups characteristic for a mixed environment. The canonical correspondence analysis (CCA) demonstrated that nutrients and temperature were significant environmental variables for their development. The sequence of phytoplankton seasonality, vertical distribution of phytoplankton, as well as the domination of rapidly acclimating phytoplankton forms (R-strategists) indicated clear, well-mixed conditions and a highly disturbed environment. Our results suggest that the occurrence of extreme flooding can be a stressor high enough for the transition from a turbid to a clear state of the floodplain lake. Possibly, cyclic shifts between alternative stable states in floodplain ecosystems can be expected as a consequence of the impact of extreme hydrological events induced by a climate change

Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins

Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains