Effect of water chemistry on the planktonic communities and relationships among food web components across a freshwater ecotone

Most ecological research on the food web has been focused more on the pelagic zone than on the transitional zone - ecotones between lentic and lotic habitats. The specific goals of this study were to determine whether the contact zone of waters differs in hydrochemical and biological terms from the waters of the canal and the open water zone, and to evaluate the influence of particular macro-habitats on the interactions between components of the planktonic food web. The distribution of samples in ordination space led us to conclude that the studied habitats are distributed along the rising gradient of total organic carbon and nutrients. Assemblages of all investigated groups showed a strong compositional gradient correlated with conductivity and total phosphorus, while a second strong gradient in species composition was explained by nitrate nitrogen and/or phosphate concentrations. The analysis of trophic relationships in the system bacteriaciliates- crustaceans reveals a clear differentiation and strength of mutual relations between the analyzed zones. The highest number of significant correlations was determined in the contact zone. It can also be a place of very efficient matter and energy flow in freshwater ecosystems

Evaluating the use of dominant microbial consumers (testate amoebae) as indicators of blanket peatland restoration

Peatlands represent globally-important ecosystems and carbon stores. However, large areas of peatland have been drained for agriculture, or peat has been harvested for use as fuel or in horticulture. Increasingly, these landscapes are being restored through ditch blocking and rewetting primarily to improve biodiversity and promote peat accumulation. To date we have little knowledge of how these interventions influence the microbial communities in peatlands. We compared the responses of dominant microbial consumers (testate amoebae) to drainage ditch restoration relative to unblocked ditches in a UK upland blanket peatland (Migneint, North Wales). Two techniques were used for restoration: (i) dammed ditches with re-profiling; and (ii) dammed ditches with pools of open water behind each dam. Testate communities in the inter-ditch areas changed markedly over time and between treatments illustrating the potential of this group of organisms as indicators of blanket peatland restoration status. However, the responses of testate amoebae to peat rewetting associated with restoration were partially obscured by inter-annual variability in weather conditions through the course of the experiment. Although there was considerable variability in the response of testate amoebae communities to peatland drain blocking, there were clearly more pronounced changes in samples from the dammed and reprofiled treatments including an increase in diversity, and the appearance of unambiguous wet-indicator species in relatively high abundances (including Amphitrema stenostoma, Archerella flavum, Arcella discoides type, Difflugia bacillifera and Difflugia bacillarium). This reflects a shift towards overall wetter conditions across the site and the creation of new habitats. However, water-table was not a significant control on testate amoebae in this case, suggesting a poor relationship between water table and surface moisture in this sloping blanket peatland. Our findings highlight the potential of testate amoebae as bioindicators of peatland restoration success; however, there is a need for caution as mechanisms driving change in the microbial communities may be more complex than first assumed. Several factors need to be taken into account when implementing biomonitoring studies in peatlands including: (i) the natural variability of the peatland ecosystem under changing weather conditions; (ii) any disturbance connected with the restoration procedures; and (iii) the timescales over which the ecosystem responds to the management intervention. Our results also suggest an indicator species approach based on population dynamics may be more appropriate for biomonitoring peatland restoration than examining changes at the community level

Comparative study of periphytic ciliate communities and succession on natural and artificial substrata in two shallow lakes (Eastern Poland)

The colonization and succession of periphytic ciliate communities on the natural (Phragmites australis and Typha Iatifolia) and artificial (glass slides) substrata were studied in 2 shallow lakes (Polesie Lubelskie, Eastern Poland). Sampling was done on a monthly basis from April to November 2003-2004. During each sampling occasion 6 periphton samples were collected from each type of substrata at 3 sites: the land/water contact zone, among emergent macrophytes, and at the emergent macrophytes/open water border. Irrespective of the type of substrate and trophic state, species number and densities of periphytic ciliates reached the highest value in the land/water contact zone and decreased in the direction of the area of emergent macrophytes/open water zone. In land/water contact zone, the biggest factors limiting the ciliate communities were temperature, conductivity, concentrations of total organic carbon and nutrient (Ptot and N-NH4). In turn, in the other 2 zones, the influence of chlorophyll a concentration increased

Horyzontalne rozmieszczenie orzęsków psammonowych w dwóch zróżnicowanych troficznie jeziorach: zależności z parametrami fizycznymi i chemicznymi

The aims of this study were to identify the taxonomic diversity and abundance of psammonic ciliate communities in mesotrophic and eutrophic lakes (Łęczna-Włodawa Lakeland, eastern Poland). The effect of selected physical and chemical water parameters on ciliates community was also analysed. Psammon samples were collected during three seasons: spring, summer and autumn of 2010. In each lake, in the psammolittoral, samples were collected in the euarenal, higroarenal, and hydroarenal zones. A total of 53 ciliate taxa were recorded. The highest value of the Shannon-Weaver index was recorded in summer in eutrophic lake (2.79). At the same time in mesotrophic lake, a lower value of the index was determined (0.79). The mean numbers of ciliates ranged from 516 ind.cm-3 in the eutrophic lake to 191 ind. cm-3 in the mesotrophic lake. In eutrophic lake, the highest number of ciliates was recorded in the euarenal (649 ind. cm-3), and the lowest in the higroarenal (425 ind. cm-3). In the mesotrophic lake, the highest average numbers were determined in the higroarenal (235 ind. cm-3), and the lowest in the hydroarenal (155 ind. cm-3). Irrespective of the lake trophy, Hymenostomata (Paramecium sp., Glaucoma sp., Uronema nigricans) occurred in the highest numbers (from 13 to 95%). The results demonstrated that N-NH4, P-PO4 and TOC can strongly regulate the abundance and taxonomic composition of ciliates. The strongest correlations between numbers of ciliates and physical and chemical water parameters were observed in the higro- and hydroarenal zones of the eutrophic lake.Celem pracy było poznanie struktury jakościowej i ilościowej orzęsków psammonowych w jeziorze mezotroficznym i eutroficznym (Pojezierze Łęczyńsko-Włodawskie). Analizowano również wpływ wybranych właściwości fizycznych i chemicznych wód na kształtowanie się tego specyficznego zespołu mikroorganizmów. Próby psammonu pobierano wiosną, latem i jesienią 2010 roku. W każdym zbiorniku, w psammolitoralu próby pobierano w euarenalu, higroarenalu i hydroarenalu. Łącznie stwierdzono 53 taksony orzęsków. Średnie zagęszczenie orzęsków wyniosło 516 osobn. cm-3 w jeziorze eutroficznym, zaś w mezotroficznym było niemal 2 razy niższe i osiągało 191 osobn. cm-3 piasku. W jeziorze Sumin najwyższe średnie zagęszczenie zanotowano w euarenalu 649 osobn.cm-3, najniższe zaś w higroarenalu (425 osobn. cm-3). W jeziorze mezotroficznym najwyższe średnie wartości liczebności zanotowano w higroarenalu 235 osobn. cm-3, najniższe zaś w hydroarenalu 155 osobn. cm-3. Najwyższą wartość wskaźnika Shanonna-Weavera odnotowano latem w jeziorze Sumin (2.79), w tym samym czasie w jeziorze Piaseczno odnotowano najniższą wartość tego współczynnika (0.79). Niezależnie od trofii jeziora największy udział w ogólnej liczebności orzęsków osiągały Hymenostomata (Paramecium sp., Glaucoma sp., Uronema nigricans) stanowiące od 13 do 95% ogólnej liczebności orzęsków. Stwierdzono istotne zależności pomiędzy obfitością orzęsków, a stężeniami w wodzie związków biogennych oraz całkowitego węgla organicznego, przy czym najsilniejsze korelacje odnotowano w strefach higro- i hydroarenalu jeziora eutroficznego

Biodiversity of aquatic and wetland habitats in rural areas

Obszary wiejskie zajmują w Polsce ponad 93% powierzchni kraju. Znaczna ich część jest cenna ze względu na dużą różnorodność biologiczną. Śródlądowe ekosystemy wodne obszarów wiejskich cechuje duże zróżnicowanie, zwłaszcza na północy, w krajobrazie pojeziernym. W ich skład wchodzą: jeziora, rzeki, źródła, młaki, naturalne małe zbiorniki wodne oraz zbudowane przez człowieka zbiorniki zaporowe i stawy. Wszystkie typy ekosystemów wodnych zajmują powierzchnię 4550 km², co stanowi 1,5% obszaru Polski. Duże znaczenie w utrzymaniu różnorodności siedliskowo-krajobrazowej obszarów wiejskich mają różne typy zbiorników wodnych i torfowisk oraz rzeki. Na szczególną uwagę zasługują torfowiska węglanowe w okolicach Chełma, jeziora lobeliowe na Pojezierzu Pomorskim, drobne zbiorniki wodne otoczone torfowiskami czy też zbiorniki śródpolne. Tworzą one specyficzny, często unikalny typ krajobrazu wiejskiego, stanowiąc ostoję dla wielu rzadkich gatunków roślin i zwierząt, dzięki czemu zachowują i wzbogacają różnorodność gatunkową. Największe zagrożenie dla różnorodności gatunkowej w ekosystemach stwarzają: zanieczyszczenie wód, ich eutrofizacja, osuszanie terenu oraz gatunki inwazyjne, np.: sumik karłowaty (Ictalurus nebolusus), rak pręgowaty (Orconectes limosus) i niektóre gatunki obunogów (Amphipoda). Prowadzą one do niszczenia lub zaniku specyficznych siedlisk wielu rodzimych gatunków ryb (Pisces), innych kręgowców (Vertebrata) oraz niektórych gatunków bezkręgowców (Invertebrata) wodnych. Skutecznymi sposobami wzbogacania i ochrony różnorodności biologicznej (gatunkowej, ekosystemowej i krajobrazowej) są: restytucja gatunków, czyli wprowadzanie danego gatunku roślin lub zwierząt do siedlisk uprzednio przez niego zasiedlanych; renaturalizacja, czyli odtwarzanie naturalnego stanu w zdegradowanych ekosystemach; rekultywacja, czyli przywracanie aktywności biologicznej na terenach całkowicie zdegradowanych.Rural areas occupy over 93 % of the country area in Poland . Significant part of these areas is valuable for their high biodiversity. Inland aquatic ecosystems of rural areas are characterized by a high diversity, especially in the lake landscape of Northern Poland . They consist of lakes, rivers, springs, bog-springs, small natural water reservoirs, dammed reservoirs and ponds. All types of water ecosystems cover the area of 4550 km۶ which makes 1.5 % of Poland 's area.Different types of water reservoirs, peat bogs and rivers have great importance for maintaining habitat and landscape diversity of rural areas. Special attention should be paid to carbonate peat bogs in the vicinity of Chełm, Lobelia - type lakes in Pomeranian Lakeland, small water reservoirs surrounded by peat bogs or mid-field water bodies which create specific and unique type of rural landscape, being refuges for many rare species of plants and animals. They also preserve and enrich species' diversity. The most dangerous for species diversity in water ecosystem proved to be the pollution of water, eutrophication, the so-called land reclamation and the invasion of exotic species such as: brown bullhead, spiny-cheek crayfish and some species of amphipods. All these factors lead to the destruction or disappearance of specific habitats for many native species of fish and some invertebrates. The effective ways of enriching and protecting the diversity (at species, ecosystem and landscape level) are: species restitution, i.e. introducing some plant or animal species to habitats previously settled by them, renaturalization, i.e. reconstruction of the natural status of degraded ecosystems; reclamation, i.e. restoration of biological activity in wholly devastated areas