Natural and Anthropogenic Impacts on the Macrophytes of Soft-Water Lakes of Estonia

Oligotrophic and semidystrophic lakes (water alkalinity <80 mg HCO3− L−1; dichromate oxygen consumption <40 mg O L−1) are the main habitats for rare macrophytes, especially isoetids. They are characteristic for the lakes with HCO3− ≤ 30 mg L−1; the higher alkalinity and related higher trophy level support elodeids. Anthropogenic impact on these lakes in Estonia started with flax retting and water lowering and continued with sauna building, agricultural nutrients, and holiday activities. The present overview is based on the data of the last 50 years. Anthropogenic acidification of Estonian lakes is not known, but natural dystrophication due to the inflow of humic compounds is probable. Alkalization and eutrophication are closely related, amplifying each other, and water level modifies these processes. Eutrophication increases the occupation of shallow zone by emergent belts, suppression of isoetids by elodeids, and overshadowing by phytoplankton blooms in a deeper zone or host plants by macroalgae. Fast-growing eutraphents accelerate the accumulation of organic sediments, unfavorable for isoetids. Among floating-leaved plants hybridization between rare and common species as well as introgression takes place. It is almost impossible to reverse back ecosystems that formed and balanced over thousands of years and became unbalanced during a much shorter period. Easier would be to keep functioning ecosystems

Quagmires around southern and southeastern Estonian lakes

We studied quagmires around 17 soft-water lakes in southern and southeastern Estonia. Vegetation analysis was carried out at the level of moss and field layer synusiae and plant communities. The aims of the current study were to elucidate the main factors determining the species richness of these quagmires, in order to ascertain what types of synusiae and plant communities form their vegetation, and what are their indicator species. Increasing the pH of peat-water increased the number of bryophyte species and the total number of species. The number of bryophyte species was positively related to through-flowing lakes and neighbouring forest vegetation. In total nine societies of bryophyte synusiae, 14 societies of vascular plants and eight community types were distinguished. Six community types represented minerotrophic quaking fen, and two types were classified as mixotrophic quaking bog. Our results show clearly a relative independency of synusiae; similar moss synusiae can associate with synusiae of various vascular plant societies and vice versa

Response of primary producers to water level fluctuations of Lake Peipsi

The amplitude of natural fluctuation between annual averages of the water level (WL) of Lake Peipsi (3555 km 2) is 1.5 m. A study aimed to examine the impact of WL fluctuations on phytoplankton, macrophytes, and their epiphyton was performed annually at littoral stations during 2005–2015. Also the characteristics of pelagic water were collated with the WL. Changes in littoral and pelagial phytoplankton were similar, with the exclusion of massive wind-caused accumulations of cyanobacteria in the littoral. At the lowest WL a significant increase occurred in (a) the biomass of phytoplankton and the share of phytoplankton-derived organic carbon in water and (b) the species richness and biomass of macrophytes, including submerged plants and macroalgae. The abundance of epiphytes did not reveal a clear relation with the WL. The ratios of biomasses in the years with the lowest and the highest average WL were 2.2 for Potamogeton spp. and 2.6 for phytoplankton. The assessment of ecological status at the minimum and the maximum WL differs at least by one quality class. Decisions about ecological status based on phytoplankton and large filamentous green algae at low water may be contrary to decisions based on macrophytes: high biomasses of phytoplankton and macroalgae indicate hypertrophic status, but species-rich macrovegetation and high biomasses of charophytes and elodeids are considered to be characteristic of meso- to eutrophic water bodies.This study was supported by the Estonian Target Financed Project SF0362483s03, by the Estonian State Monitoring Programme, and by the materials of the herbarium of the Department of Botany in the Institute of Agricultural and Environmental Sciences of the Estonian University of Life Sciences.This study was supported by the Estonian Target Financed Project SF0362483s03, by the Estonian State Monitoring Programme, and by the materials of the herbarium of the Department of Botany in the Institute of Agricultural and Environmental Sciences of the Estonian University of Life Sciences

Macrophyte assessment in European lakes: Diverse approaches but convergent views of 'good' ecological status

The European Water Framework Directive has been adopted by Member States to assess and manage the ecological integrity of surface waters. Specific challenges include harmonizing diverse assessment systems across Europe, linking ecological assessment to restoration measures and reaching a common view on ‘good’ ecological status. In this study, nine national macrophyte-based approaches for assessing ecological status were compared and harmonized, using a large dataset of 539 European lakes. A macrophyte common metric, representing the average standardized view of each lake by all countries, was used to compare national methods. This was also shown to reflect the total phosphorus (r2 = 0.32), total nitrogen (r2 = 0.22) as well as chlorophyll-a (r2 = 0.35–0.38) gradients, providing a link between ecological data, stressors and management decisions. Despite differing assessment approaches and initial differences in classification, a consensus was reached on how type-specific macrophyte assemblages change across the ecological status gradient and where ecological status boundaries should lie. A marked decline in submerged vegetation, especially Charophyta (characterizing ‘good’ status), and an increase in abundance of free-floating plants (characterizing ‘less than good’ status) were the most significant changes along the ecological status gradient. Macrophyte communities of ‘good’ status lakes were diverse with many charophytes and several Potamogeton species. A large number of taxa occurred across the entire gradient, but only a minority dominated at ‘less than good’ status, including filamentous algae, lemnids, nymphaeids, and several elodeids (e.g., Zannichellia palustris and Elodea nuttallii). Our findings establish a ‘guiding image’ of the macrophyte community at ‘good’ ecological status in hard-water lakes of the Central-Baltic region of Europe

Siseveekogud : õpik kõrgkoolidele

Inimeste kõige tavalisemad seosed siseveekogudega on matkamine, kalapüük, suplemine, janu kustutamine ja taimede kastmine. Et veekogude ääres viibimine mõjub paljudele rahustavalt, on jõgedel-järvedel miljonivaadete kaudu kindel koht ka kinnisvaraäris. Veekogudeta ei saa läbi sportlased (purjetajad, sõudjad ja motohuvilised). Leidub selliseidki indiviide, keda meelitavad mittesöödavad või koguni palja silmaga nähtamatud vee-elanikud. Eesti on väike madal maa, millel on pikk mererand, aga kus leidub ka palju siseveekogusid. Eriline on kahe suure järve – Peipsi ja Võrtsjärve – asumine lähestikku. Seisuvete pindala osakaalu järgi kogu riigi pindalast on Eesti Euroopas pärast Soomet ja Rootsit koos Norraga kolmandal-neljandal kohal. Eesti ja tema ümbrus on puhta veega seni niisiis hästi varustatud, kuid see rikkus ühtlasi kohustab veekogusid heaperemehelikult ja jätkusuutlikult majandama. Ka Eestis on muresid nii veevarude, veekogude kui nende seisundiga. Sisevete uurimine on Eestis kestnud juba üle 100 aasta. Seda on süstemaatiliselt korraldanud nii Looduseuurijate Selts, Tartu Riiklik Ülikool, Teaduste Akadeemia kui Maaülikool. Suurte järvede kõrval pole unustatud väikesi järvi ega vooluveekogusid. Uurida vee ja veekogude omadusi, arendada ja kasvatada nende spetsialiste ongi mõistlik seal, kus on, mida tundma õppida. Üha enam leitakse seoseid looduslike ja inimtekkeliste mõjurite ning ökosüsteemide vastuste vahel. Ühtlasi ühendatakse neid seoseid sotsiaalmajanduslike küsimuste ja looduskaitsega. Eesti siseveekogude kohta on peale arvukate ja enamasti võõrkeelsete teadusartiklite ilmunud ka eestikeelseid raamatuid. Siin neist väike loetelu: väikejärved (Eesti järved, 1968; Mäemets, 1977; Laarmaa jt 2019); Võrtsjärv (1973, 2003); Peipsi (1999, 2008), vooluveed (Järvekülg jt 2001; Timm jt 2019). Kalaraamatuid esindavad Mikelsaar (1984) ning Hunt (2019), veetaimi „Eesti taimede määraja“ (2010). Silmaga nähtavate veeselgrootute ülevaate pakub Timm (2015). Ülevaatlikku eestikeelset õpikut siseveekogude ning nende talitlemise kohta seni polnud. Eesti ülikoolides on kõigil kolmel õppetasandil (bakalaureuse-, magistri- ja doktoriõpe) õppekavasid, kus vajatakse teadmisi siseveekogudest. Võõrkeelseid eeskujusid leidub päris mitu, kuid need käsitlevad enamasti kas ainult hüdrobioloogiat või limnoloogiat. Esimene on elustiku-, teine keskkonna-alase suunitlusega. Uus õpik sisaldab mõlemaid ning sobib loodetavasti paljudele loodusteaduslikele ja looduskaitselistele kursustele, eriti bakalaureusetasemel. Õpik koosneb kolmest suurest alajaotusest: (1) siseveekogude füüsikalis-keemiline iseloomustus, levik ja teke; (2) elupaigad veekogudes, olulised elustikurühmad ning nendevahelised suhted; (3) siseveekogude majandamine, kaitse ja tervendamine. Peamiselt vaadeldakse Eesti siseveekogusid, aga seda kogu maailma taustal. Koostajad loodavad, et raamat annab lugejatele nii vastuseid küsimustele kui ka süvendab huvi sisevete kui kaunite, põnevate ning inimestele eluliselt oluliste loodusobjektide suhtes.Õpik on valminud riikliku programmi „Eestikeelsete kõrgkooliõpikute koostamine ja väljaandmine (2008–2012)“ raames ning Eesti Maaülikooli ja Sihtasutuse Archimedes osalisel toel

Commented list of rare and protected vascular plants of inland water bodies of Estonia

This presented overview of rare and protected hydrophytes, emergent plants and hygrophytes of inland water bodies of Estonia includes 60 species. In the commented list are indicated their position in the state protection categories I–III (last version in 2014), and under the Red List of Estonia (last version in 2008); marked are Natura 2000 species of the European Union. Most typical habitats for these rare species are: I. soft-water oligotrophic and semidystrophic lakes; II. mesotrophic lakes with Najas (Caulinia) flexilis and Potamogeton rutilus; III. alkaline fens and wet meadows; IV. brackish or freshwater coastal lagoons; V. undamaged river stretches; VI. open shallow littoral of the largest lakes of Peipsi (Pskovsko-Chudskoe) and of Võrtsjärv. Main threats of these habitats are briefly concerned, as well as the problem of conservation value of hybrids, based on the example of Sparganium species

Macrophyte data of Lake Peipsi

Macrophyte data of Lake Peipsi has been collected from ten different stations (locations with coordinates in the dataset) starting from 2005, during the Estonian National Monitoring of Environment. Species composition and abundances were registered on the transects starting from upper boundary of the temporarily flooded zone to the deepest growth zone. The width of the transect was ca 20 meters on the shore and near the water´s edge and ca 10 m in deeper water. The abundance was estimated on a 1-5-point scale: 1 - single plant or few plants; 2 - scattered plants or some small stands; 3 - numerous, frequent in the observation area; 4 - dominant or codominant; 5 - mass occurrence, absolute dominant (Mäemets et al., 2010). Taxon ID originates from the database: https://www.freshwaterecology.info (according Schmidt-Kloiber, A. & Hering, D., 2015; 2022). For some taxa with more eastern distribution ID was lacking in this database.ReferencesMäemets, H., Palmik, K., Sudnitsyna, D. & Melnik, M. (2010) Eutrophication and macrophyte species richness in the large shallow North-European Lake Peipsi. Aquatic Botany 92:273-280.Schmidt-Kloiber, A. & Hering D. (2015): www.freshwaterecology.info - an online tool that unifies, standardises and codifies more than 20,000 European freshwater organisms and their ecological preferences. Ecological Indicators 53: 271-282. doi: 10.1016/j.ecolind.2015.02.007Schmidt-Kloiber A. & Hering D. (eds.): www.freshwaterecology.info - the taxa and autecology database for freshwater organisms, version 8.0 (accessed on 22.11.2022)

Outcomes of the littoral monitoring of a large shallow lake: a case of Lake Peipsi : [presentation]

The presentation took place at the 11th International Shallow Lakes Conference.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 951963, and was supported by the Estonian State Monitoring Programme.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 951963, and was supported by the Estonian State Monitoring Programme

Lake Peipsi 2012 (Littoral samples)

Phytoplankton samples were picked with bottle from among reed stands or from above thick beds of submerged plants from the depth 20-30 cm, were preserved in Lugol’s (acidified iodine) solution and counted under an inverted microscope (Utermöhl, 1958). 3 ml of preserved sample was settled overnight and counted in random fields or transects. Biovolumes of algal cells, colonies and/or filaments were calculated using assigned geometric shapes dimensions, and converted to biomass assuming the specific density of 1 g cm-3 in accordance with Edler (1979). Macroscopic colonies of Gloeotrichia echinulata were enumerated visually in 500 ml measuring cylinder. Counting units are independent (single) algal cells, colonies or filaments/trichomes. One species or taxon may be present in the sample as different counting units and may be counted at different magnifications. References of methods accepted Approved by CEN on 14 July 2006 “Water quality - Guidance standard on the enumeration of phytoplankton using inverted microscopy (Utermöhl technique)” (CEN 15204, 2006) European Standard EN 15204:2006 Utermöhl, H., 1958. Zur Vervollkommnung der quantitativen Phytoplankton-Methodik. Mitteilungen der Internationale Vereinigung für Theoretische und Angewandte Limnologie 9, 1-38. Edler, L. (ed.), 1979. Recommendations on methods for marine biological studies in the Baltic Sea. Phytoplankton and chlorophyll. Baltic Marine Biologists WG 9. (13) Biovolume calculation for pelagic and benthic microalgae | Request PDF. Available from: https://www.researchgate.net/publication/220031275_Biovolume_calculation_for_pelagic_and_benthic_microalgae [accessed Oct 29 2018]. The most commonly used traditional biomass estimate for microalgae is cell biovolume, which is calculated from microscopically measured linear dimensions (Steinman et al. 1991, Snoeijs 1994, Sommer 1994, 1995, Hillebrand and Sommer 1997). Hand-books, most representative Huber-Pestalozzi, G., Komarek, J., Fott, B. 1983. Das Phytoplankton des Süsswassers. 7(1). Chlorophyceae. Chlorococcales. Stuttgart. 1044. S. Komarek, J., Anagnostidis, K. 1999. Süsswasserflora von Mitteleuropa. 19/1. Cyanoprocaryota. 1. Chroococcales. Elsevier Spectrum Academischer Verlag. Heidelberg. Berlin. 548 S. Komarek, J., Anagnostidis, K. 2005. Süsswasserflora von Mitteleuropa. 19/2. Cyanoprocaryota. 2. Oscillatoriales. Elsevier Spectrum Academischer Verlag. 759 S. Komárek, J., 2013. Cyanoprokaryota 3. Teil: Heterocystous Genera. Süsswasserflora von Mitteleuropa. B. 19/3. Springer Spektrum. 1130 S. Krammer, K., Lange-Bertalot, H. 1997-1991. Süsswasserflora von Mitteleuropa. Bacillariophyceae. B. 2, 1-4. Spectrum Academischer Verlag.Heidelberg. Berlin.. Popovský, J., Pfiester, L.A. 20008. Dinophyceae (Dinoflagellida). Süsswasserflora von Mitteleuropa. B. 6. Springer Spektrum. 272 S. Косинская Е.К. 1960. Флора споровых растений СССР. Том 5. Конъюгаты и Сцеплянки. (2). Изд. АН СССР. Москва-Ленинград. 706 стр. In Russian. Korshikov, A.A. (1953). Viznachnik prisnovodnikh vodorosley Ukrainsykoi RSR [Vyp] V. Pidklas Protokokovi (Protococcineae). Bakuol'ni (Vacuolales) ta Protokokovi (Protococcales) [The Freshwater Algae of the Ukrainian SSR. V. Sub-Class Protococcineae. Vacuolales and Protococcales]. pp. 1-439. Kyjv [Kiev]: Akad. NAUK URSR. In Ukrainian. Матвiенко О.М. 1965. Визначник прiсноводных водоростей Украǐнской РСР. 3. Частина 1. Золотисти водорости – Chrysophyta. Изд. Наукова Думка. Киǐв. 367 стр. In Ukrainian. Попова Т.Г. 1955. Определитель пресноводных водорослей. Вып. 7. Эвгленовые водоросли. Изд. Советская Наука, Москва. 282 стр. In Russian