Karel PRACH

1. Does spontaneous succession lead towards target vegetation in abandoned fields? A survey across Europe Karel PRACH Department of Botany, Faculty of Biological Sciences USB, České Budĕjovice; and Institute of Botany, Academy of Sciences of the Czech Republic,Třeboň

2. Main tasks:The core question is in the title: Does spontaneous succession lead towards target vegetation in abandoned fields? Others: What environmental factors influence the course of succession?What we expect in abandoned fields and how to reach the targets by spontaneous or reasonably manipulated succession?

6. Photo: M. Jonášová

18. Doupovské hory, 8/2005

21. Photo: A. Csetcserits

25. Foto E. Ruprecht

28. More or less stabilized successional stages developed spontaneously in old-fields

30. (adapted from Prach, Lepš, Rejmánek 2007) 64 common weeds 39 83 dry mesic wet

31. suchá mezická vlhká

32. poblíž obce Broumy, 2006

33. Annual weeds Perennial weeds and ruderals Meadow species Woodland species >12 yr 1.Betula pendula, 2.Pinus sylvestris, 3. Salix caprea, 4.S. phylicifolia, 5.Alnus incana, 6.Betula pubescens, 7.Populus tremula, 8.Rosa dumalis, 9.Malus sylvestris, 10.Picea abies, 11.Salix lapponum Luzula pilosa, Melampyrum sylvaticum, Anemone nemorosa, Convallaria majalis, Hepatica nobilis, Viola riviniana, Maianthemum bifolium

34. The most important environmental factors affecting succession and their potential manipulation to reach targets:Macroclimate: manipulationimpossibleSurrounding vegetation: elimination of invasive aliensSoil moisture: difficult and not neededNutrients: top soil removal in heavily fertilized soilsAdditional disturbances: very powerful tool (cutting, grazing, elimination or planting of woody species)Because arable soil is sufficiently fertile, there is usually no need for physical manipulation of the environment and only biological manipulations can be considered (exception: sod cutting in some heavily fertlilized soil).

35. Targets:(i) reserved fields(elimination of establishment of woody species)(ii) cut meadows and pastures(spontaneous succession at the beginning, then mowing or grazing, elimination of woody speciesif succession proceeded behind grassy stage, sowing of target grasses)(iii) timber production(planting trees or spontaneous succession)(iv) stands of conservation values(spontaneous succession, elimination of invasive aliens and other competitive species, sowing or transplanting target species)(v) buffer zones(usually spontaneous succession)(vi) protection againserosion(usually spontaneous succession)

36. Conclusions:In most cases, reasonable targets, i.e. seminatural communities, are reached by spontaneous, unassisted succession after app. 20 years (usually woodland in N, W and C Europe, grassland in E and dry sites in C Europe, scrubland or shrubby grassland in Mediterran). This is more probable in landscapes which have retained traditional agricultural practices, and where soils have not been altered markedly by over-fertilization or drainage, and where (semi)natural habitats still frequently occur in the vicinity. Conversely, in altered landscapes, competitive ruderals (generalists) or aliens may expand. Reasonable manipulation of succession may help to reach practical targets.

37. Thank you for your attention

38. Obnova ekosystémů na orné půděna úrovni krajiny (úpravy):sklon svahu nad 25º – trvalý travní porost, nad 50º zalesněníDoporučené šířky pásů oraných pozemků: Sklon svahu [º] Šířka pásů [m]3-8 309-16 2417-20 1821-25 15vegetační pásy mezi pozemky, vrstevnicová orba aj.u nás nejvyšší míra zornění v Evropě (75% zemědělského půdního fondu, dnes cca 72%)