Urve Ratas

Implications of Sea-Level Rise for Estonia

Abstract Estonia is a coastal country with a long coastline (3800 km) for which climate change and accelerated sea-level rise are key problems that need to be considered in any future impact assessment. Due to its flat, low-lying coastal zone, any rise in sea level places many coastal ecosystems and recreationally valuable sandy beaches at risk. Milder winters, combined with increased storminess and the absence of sea-ice cover, would exacerbate these impacts. However, isostatic uplift and the distance of coastal settlements from the present coastline could reduce these risks. This paper presents the potential impact of a 1-m global sea-level rise by 2100 if no adaptation is undertaken. Seven representative study areas, characterising all shore types in Estonia, were selected for sea-level rise vulnerability and adaptation assessment. The diverse structure of Estonias coasts, the rapidly migrating shorelines, and the abundance of small islands were found to complicate reliable predictions regarding climate warming and accelerated sea-level rise. SISUTUTVUSTUS: Eesti on pika rannajoonega (3800 km) mereäärne maa. Seetõttu on võimalik meretaseme tõus üks võtmeküsimusi kliima muutuse mõju hindamisel Eesti jaoks. Kuna siinne rannik on valdavalt madal ja tasane, on paljud väärtuslikud rannikuökosüsteemid kliima muutuse ja meretaseme tõusu korral hävimisohus. Paljud kõrge rekreatiivse väärtusega liivarannad lakkaksid eksisteerimast. Kliima muutusega kaasnevate pehmete talvede, jääkatte puudumise ning sagedaste tormide koosmõju teravdaksid veelgi ülalmainitud protsesse. Ent isostaatiline maakerge ja rannikuäärsete asulate paiknemine tänapäeva rannajoonest eemal mõnevõrra leevendavad riski suurust. Käesolevas artiklis on esitatud analüüsi tulemused aastaks 2100 toimuva 1 meetrise globaalse meretaseme tõusu stsenaariumi järgi tingimusel, et mingeid kaitse- ega kohandamismeetmeid ei võeta eelnevalt tarvitusele. Meretaseme tõusuga kaasneva rannikualade haavatavuse ning selle tagajärgedele vastavate kaitse- ja kohandamismeetmete analüüsiks valiti seitse võtmeala, mis esindavad kõiki peamisi Eesti rannikutüüpe. Eesti rannikutüüpide vahel-dusrikkus, kiiresti muutuv rannajoon ning saarte rohkus teevad kliima soojenemise ning meretaseme tõusu võimalike tagajärgede ennustamise väga keerukaks.

Sea-level rise impact on coastal areas of Estonia

Due to long coastline (3,794 km in total) and extensive low-lying coastal areas, global climate change through sea-level rise will strongly affect the territory of Estonia. A number of valuable natural ecosystems (both, marine and terrestrial) containing rare plant communities often rich in species, but also suitable breeding places for birds will be in danger. Most sandy beaches high in recreative value will disappear. However, isostatic land uplift and location of coastal settlements at a distance from the present coastline reduce the rate of risk. Four case study areas characterizing all the shore types of Estonia have been selected for sea-level rise vulnerability and adaptation assessment. Preliminary results and estimates of vulnerability to 1.0 m sea-level rise by 2075 for two case study areas – Hiiumaa, West-Estonian Archipelago and Pärnu-Ikla, south-western coast of the mainland – are presented in this paper.

Changes of coastal dune landscapes in Estonia

Changes of coastal dune landscapes in Estonia Coastal landscapes are strongly affected by their geomorphology, based on the character of deposits and moisture conditions. The main influences on the aeolian ecosystems of coastal areas are heavy winds, salt spray and lack of nutrients. An increase in the frequency of storms in coastal waters may result in the erosion of beaches that were previously stable or prograding. Coastal dune ecosystems are in different stages of vegetation succession and soil development. At present coastal dune landscapes are being rapidly changed by waves and human impact. In the last decade, research on the geomorphologic changes of the coast in Estonia has been quite noteworthy, but the associated changes in ecosystems have been little considered. The main problem for coastal dunes landscape is the decrease of natural habitats due to afforestation, recreation and building. In this paper our attention is focused on changes of Estonian coastal dune landscapes during the last one hundred years. Muutused Eesti luitelistes rannikumaastikes Urve Maa ja mere piiril kujunenud luitelised rannikumaastikud on noored ja kiiresti muutuvad nii looduslike protsesside kui ka inimtegevuse mõjul. Enamus neist on kujunenud Limneamere staadiumi jooksul. Maastikuliselt enamlevinud on madalatest luitestunud rannavallidest liigestatud mereliivatasandikud (Võsu, Rammu, Prangli jt.), kuid esineb ka hästi väljakujunenud luidetega alasid (Keibu). Nende piires saab eraldada aktiivse liivaranna ja sellest sisemaa sunnas jääva vanema rannamoodustistega ala. Aktiivsetes liivarandades muld puudub, taimkattes esinevad ranna alumises osas üheaastased nitrofiilsed taimekooslused, ranna ülaossa jääb merihumura ja liiv-vareskaera kooslus, mille juurestik tungib sügavale ning mis aitavad kinnistada liivasid. Rannikumaastike siseosa on enamasti metsastunud, väikesel pindalal kohtab taimestumata liivikuid. Siin esineb ka kuivi nõmmerohumaid ning Eesti põhjarannikul isegi kukemarjanõmmesid. Metsa ja nüüdisranna vahele jäävad alad, kus luitelistel rannavallidel kasvab liiv-vareskaer, Eesti saartel ja ka mandri äärmises lääneosas aga luidekaer. Luitelised rannikumaastikud on kergesti haavatavad, kus intensiivne kasutus toob kaasa liivade liikumise. Sisemaal toimunud muutustest annab ettekujutuse maakatte muutus. Eelmise sajandi jooksul toimus uuringualadel metsamaa suurenemine rohumaa ja lahtiste liivikute arvelt. Muutused viimastel aastakümnetel on aga palju väiksemad, mis suuresti seotud siinsete metsade võtmisega kaitse alla (Keibu). Huvitav on märkida, et sama tendents esineb ka Võsu uuringualal, kuhu jääb ka osa Võsu alevikust. Suuri ja kiireid muutusi võivad põhjustada siinsetes metsamaastikes metsatulekahjud, tugevate tuultega kaasnev tormimurd ja lagedate alade metsastamine (Rammu), mis toob kaasa avakoosluste kiirendatud kadumise. Viimastel aastakümnetel toimunud tormisuse suurenemine ning sellega kaasnenud ajutine merevee tõus on kutsunud esile liivarandades suuri muutusi. Rannajoone muutused toovad kaasa ka muutused taimkattes. Enamasti iseloomustavad meie liivarandasid kulutusprotsessid, mille tulemusena rannajoon nihkub sisemaa suunas ning koos sellega kaovad mitmete taimede elupaigad. Uusi kuhjepiirkondi kohtab rannas aga harva, sageli väljendub see liivaste maasäärte tekkimises, mis toob kaasa uute elupaikade kujunemise. Luitelisi rannikumaastikke kasutatakse praegu intensiivselt puhkekohtadena, samuti ohustab neid suuremate keskuste juures ehitustegevus. Kõik see toob kaasa mitmete elupaikade hävimise või nende seisundi halvenemise. Luiteliste rannikumaastike kaitseks ja säilimiseks on vajalikud integreeritud planeeringud, kus aktiivset liivaranda ja sellega piirnevat sisemaapoolset ala tuleb käsitleda ühtse tervikuna.

Changing natural and human impacts on the development of coastal land cover in Estonia

ABSTRACT Antso, K., Kont, A., Palginõmm, V., Ratas, U., Rivis, R. and Tõnisson, H. 2013. Changing natural and human impacts on the development of coastal land cover in Estonia. The structure of coastal land cover in Estonia is variable and shows considerable differences from site to site. The diverse geomorphology of the seashores is one of the key factors causing different velocity and magnitude of changes while the countrys history of settling the coast has also shaped the character of land cover. The main objectives of the current paper are: 1) to give an overview of land use and the trends of development of land cover pattern in different parts of the Estonias coast; 2) to analyze the relationships of natural and man-induced processes and their cumulative impact on the evolution of coastal land cover pattern in Estonia. The current paper focuses mainly on changes in land cover in agricultural areas and on small islands. In predominating agricultural coastal areas, the traditional open landscape of fields and grassland in the beginning of the 20th century has been replaced by woodland and grassland with shrubs by the start of the 21st century. Expansion of reed beds in the areas of former seashore grasslands is another striking phenomenon. The evolution of the landscapes on small islands is strongly dependent on the character of their formation and is well reflecting the relationships of vegetation, topography and moisture conditions. Cessation of traditional land use, rapid increase in coastal population and expansion of built-up areas in recent decades, together with higher storm activity, create stresses on the coast that threaten both nature and man.

Aeolian Activity on the Northern Coast of Lake Peipsi, North-Eastern Estonia

ABSTRACT Ratas, U.; Raukas, A.; Rivis, R., and Tavast, E., 2015. Aeolian activity on the northern coast of Lake Peipsi, north-eastern Estonia. Lake Peipsi is one of the largest inland water bodies in Europe. In the geological past, it was much bigger, flooding vast areas to the north of the contemporary lake. In the proglacial lakes formed behind the retreating glacier, large amounts of sand and silt accumulated, providing source material for various aeolian deposits and landforms, such as coversand hillocks, blowouts, deflation hollows, foredunes, inland and coastal dunes, and wind-eroded plains. Because of land uplift they are of different age (from the Late Glacial up to the present) and structure. The oldest dunes in the area were formed in severe climatic conditions of the Younger Dryas and the Early pre-Boreal. Near the contemporary shoreline of Lake Peipsi, the rhythmically changing water level has strongly influenced the aeolian redistribution of sediments. Here specific “basket-trap” dunes were formed behind rather huge parabolic wind ditches, which developed at sites where the vegetation cover had been locally breached by wave erosion, ice action, or human influence. In different parts of individual dunes variations in grain size and mineral composition are slight, but regional differences are noteworthy. The northern coast of Lake Peipsi has a great recreational value.

Ground-penetrating radar studies along the coast of Estonia

ABSTRACT Vilumaa, K., Tõnisson, H., Kont, A. and Ratas, U., 2013 Ground-penetrating radar studies along the coast of Estonia. Ground-penetrating radar (GPR) profiling has been performed in the study sites in west Estonian archipelago (Röögu, Lõimastu) and on the northern coast of the mainland (Juminda). The west Estonian study sites have emerged during regressive phases of the Limnea Sea. The coastal landforms there are younger and smaller than the landforms in northern Estonia, which have emerged at the beginning of the Ancylus Lake stage of the Baltic Sea. The study sites are characterized by a series of beach ridges, which are parallel to the shoreline. These ridges are separated by narrow and wet depressions where non-calcareous sand is covered with peat. The beach ridges are located at different distance from the current shore and at different altitudes. The results are based on cartographic analysis, topographic survey and georadar (SIR-3000, 100 MHz frequency) survey along transects. About 1 km long GPR profiles perpendicular to the ridges were examined. The GPR data were calibrated and compared with peat coring data. The average electromagnetic wave (EMW) speed values were: 0.035 m/ns for peat and 0.05 m/ns for sand. The study was conducted in order to determine the thickness of peat (0.2–2.0 m) and to characterize the topography of sub-peat mineral surface. Two different patterns of bedding in the sand layer can be detected. The top layers (1–1.5 m), which are probably of aeolian origin, are almost parallel to the surface of the initial beach ridges. Most of the lower layers are tilted seaward. Those layers may indicate a cross-shore transport of sand by waves.