Succession in dune habitats in the Nature Park “Piejūra”, Latvia Brigita Laime, Didzis Tjarve Department of Botany and Ecology, Faculty of Biology, University of Latvia, [email protected], [email protected] 2020. 01.10. LIFE CoHaBit "Coastal Habitat Conservation in Nature Park "Piejūra"", LIFE15 NAT/LV/000900 Introduction • Coastal dune habitats belong to very dynamic ecosystems which depend directly on sand deposition and other physical factors. Along the coast of the Nature Park “Piejūra” accumulation processes are dominated and one of the largest open dune areas in Latvia there is formed. The development of coastal dune habitats was significantly affected 15 years ago by strong storm. Introduction • Nowadays, a total area o of primary dunes (habitats 2110 Embryonic shifting dunes and 2120 Shifting dunes along the shoreline with Ammophila arenaria (white dunes)) is 71 hectares, o of grey dunes (2130* Fixed coastal dunes with herbaceous vegetation) 280 hectares, o and wooded dunes (2180 Wooded dunes of the Atlantic, Continental and Boreal region) reaches 2770 hectares. • All of these habitats are influenced by sea coast visitors, land use change, coastal processes, invasive plant species, eutrophication and other pressures and threats. Vegetation succession in dunes - psammosere • From bare sand - to pioneer species – to climax vegetation Beach Primary dundes Secondary dunes The aim of the study • Evaluation of habitat quality was focused on grey dune habitats, their vegetation succession, and lichen rich pine forest. Material and methods • In a period from a lac Sa Seashore types in Latvia Ainaþi Salacgrîva 2002 to 2020, Svçtupe Kolka Mazirbe V i t Melnsils r rbe u I p changes in dune Ovîði Ì ipka e S t e Limbaþi n R R o i d ja Roja n e d Tûja a VENTSPILS Valdemârpils habitats were Mçrsrags ì e A Uþava Piltene Engures Talsi ez. Saulkrasti Usmas U þa observed in two v ez. Engure a Stende Carnikava Abava Sabile Vangaþi Jûrkalne Kandava Í îðezers Ragaciems monitoring Kuldîga Tukums Pâvilosta RÎGA Saka JÛRMALA Babîtes ez. Ikðí ile D Te Baloþi bra Ogre ur Kalnciems stations be Olaine M Ziemupe is Aizpute Ciec a Baldone ere Bçrze Durbes ez. Brocçni Wide Cieceressandy beaches Saldus JELGAVA L I Dobele i ec Durbe ez. e av (Daugavgrīva and LIEPÂJA l a a u Grobiòa Low wet beaches v p a e V c r e i Liepâjas e t n ç V t v Priekule a Auce S a ez. Sandy gravel beaches v a Bauska s e M e n Lilaste), located on S e M t ç Bârt i Î m a v s û Pebble beaches S l e î l c s e Jûrmalciems e a Boulder beaches the southern coast Papes ez. Pape Coastal wetlands and meadows of the Gulf of Riga. Nida Daugavgrīva Lilaste Material and methods • Vegetation structure, plant species composition and cover were characterised in 178 plots (each plot 1 m x 1 m), placed along six transects from beach to wooded dunes, three times during the monitoring period; in addition, the dune forest was described in several places. Results Open grey dune characteristic in Daugavgrīva % Cover Trees shrubs herbs mosses lichens bare sand litter paths Results Characteristic of grey dunes, overgrown with trees and shrubs in Daugavgrīva Results • During last 18 years tree (Pinus sylvestris, Betula pendula) and shrub (Salix daphnoides) cover in grey dunes is significantly increase. Results • Tree and shrub litter is abundant in many plots; it forms a thick layer and directly influences the development of humus layer. Results • Bare soil patches are absent or very rare (sample plot is covered with litter or dead grass). Results Expansion of Hylocomium splendens and Pleurozium schreberii • On some places mosses Pleurozium schreberi and Hylocomium splendens dominate and form a layer of 5 or more centimeter; and lichens are absent or can be found in small patches. • The abundance of invasive plant species Lactuca tatarica increases in open dune habitats, mainly in foredunes and ecotonzone to grey dunes. Succession from white dune to grey dune and wooded dune, Daugavgrīva Salix daphnoides shrubs – influential ecological factor in grey dunes Willow bushes in the grey dunes - one of the pine habitat. Under the influence of recreation, the dune micro-relief is changed. Lilaste, 2005. With increasing of tree litter rapidly decreases cover of moss Tortula ruralis Conclusions • The area and quality of grey dune habitats in the Nature Park “Piejūra” decreases rapidly. • Overgrowing with trees and shrubs is the main threat. • In both monitoring stations, number of characteristic plant species of grey dune habitat decreases. • Active management (cutting of trees, removal of litter and topsoil) is necessary in grey dune and some wooded dune areas. More about the monitoring results please see Monitoring of seacoast habitats http://biodiv.daba.gov.lv/fol302307/fol0 38572/fol579889 .