|Účinnost nechemických metod kontroly šťovíku alpského (Rumex alpinus) na vysokohorské pastvině ve Slovinsku|
|Effectiveness of non-chemical methods to control alpine dock (Rumex alpinus) on an alpine pasture in Slovenia|
|Marija Gregori; Urban Šilc|
Šťovíky (Rumex spp.) představují obtížné plevele na polích i trvalých travních porostech. Druh Šťovík
alpský (Rumex alpinus) je silně nitrofilní druh, který roste na vlhké půdě; jeho výskyt se tradičně pojí s umístěním
hnojišť a jinak eutrofi zovaných míst v blízkosti hospodářských budov. Tento článek shrnuje hlavní výsledky experimentu
s likvidací šťovíku alpského na horské pastvině Korošica ve Slovinsku. Zkoušeli jsme efektivitu šesti zásahů:
seč, vypalování, zakrytí fólií, ruční vykopávání, spásání skotem a vepři. Největší redukce bylo dosaženo sečí, zakrytím
fólií a ručním vykopáváním.
Docks (Rumex spp.) are troublesome weeds in agricultural lands with arable crops or permanent grasslands.
Rumex alpinus is strongly nitrophilous and grows in damp soil, and is associated with dung and waste from
domestic animals near farm buildings. This article summarizes the key results of tests on the effectiveness of different
methods of alpine dock disposal on the mountain pasture Korošica (Slovenia). Six treatments were tested:
mowing, heating, foil cover, manual removal, and grazing by cattle or pigs. The largest reduction of R. alpinus was
achieved by mowing, foil covering and manual excavation.
|Alpine meadows on limestone in Slovenia are generally very species-rich often with a large number of endemic and / or endangered plant species. Alpine pastures were often not properly managed in the middle of the last century. This led to a change in species composition; new weeds and plants unwanted in terms of pasturing and nature conservation started to emerge. This is responsible for the expansion of nitrophilous plant species, of which Rumex alpinus (alpine dock) is the most signifi cant. Alpine dock is a very powerful competitor due to its growth form, formation of broad leaves and tall generative shoots and can turn a plant community into a monoculture within a few years. This article summarizes the key results of tests on the effectiveness of different methods of alpine dock disposal on the mountain pasture Korošica, where the uncontrolled spread of these plants is most pronounced. The aim of our study was to investigate the use and effectiveness of various non-chemical methods on alpine dock removal. The experiment was done on the Korošica mountain pasture (1 554 m), which has been a part of the Karavanke Natura 2000 locality since 2004. The importance of the Korošica mountain pasture to nature conservation has critically decreased in recent years because of the uncontrolled and excessive growth of alpine dock, which now occupies 9 % of the grazing area. Testing of the sustainable removal of alpine dock lasted three vegetation seasons (June 2012 – September 2014, see Tab. 1. for schedule of individual treatments). Six treatments were tested against a control: mowing, heating, foil cover, manual removal, and grazing by either cattle or pigs. For Mowing, Heat, Foil and Manual excavation we used four replicates (each replicate 4 × 4 m and 3 years of testing), while for Cattle grazing (Fig. 4) we used one replicate (10 × 15 m) for only one year, and Pigs grazing also one replicate (10 × 15 m) for 4 weeks and only in the first year (Fig. 5). After treatment of the plots, we sowed them with a suitable commercial grass seed mixture. The vegetation was sampled according to the Braun-Blanquet method. For the mowing, heat, foil and manual treatments, we sampled whole plots, while we sampled two randomly selected plots in the animal treatments. All data were sampled prior to the start of the experiment, except for biomass, and repeatedly at the end of every vegetation season. Changes in fl oristic composition of the initial plant community (Rumicetum alpini) differed among treatments. The greatest changes in species composition were in plots covered by foil and those subjected to manual excavation (Tab. 2). Changes were less pronounced and gradual in the other treatments. Comparisons within treatments showed signifi cant differences in the biomass of alpine dock between the first year and the following two for Manual excavation, Foil Cover and Mowing, while Heat did not differ from Control (Fig. 7, Tab. 3). There was a significant reduction in the cover of alpine dock for Manual excavation and Foil Cover (Fig. 8), while Mowing significantly reduced the cover only after the second year. The number of shoots was signifi cantly lowered by Manual excavation, Foil Cover and Mowing (Fig. 9). The number also varied among years, since sampling of particular shoots is very subjective, although it was done by the same observer. Although docks are very important weeds in grasslands, most control studies have been done on “lowland” species, e.g., R. obtusifolius and R. crispus. The largest reduction of alpine dock was achieved by mowing, foil covering and manual excavation. The frequency of cutting is the most important factor. The reduction of cover and biomass by mowing was very gradual compared to foil and manual excavation. The combination of mowing and grass seeding proved to be successful. It is important to cut dock at a height of 10 cm to enable other herbs to regenerate faster than Rumex. Excavation successfully removed dock plants but it is a very time consuming method, because it is necessary to remove and destroy the roots and rhizomes so they cannot regenerate. Covering by foil to reduce the light to weeds or any other invasive species is a common practice. After one year, the docks were destroyed due to reduced light and high temperatures under the foil in the summer period. Foil is less suitable for large areas. Treatment with flame reduced the biomass of alpine docks but not their cover and the docks regenerated after the fi rst year. In the case of large patches, all plants were damaged by the heat and the herbs were unable to compete with the docks during subsequent resprouting. Rumex species are rarely grazed by animals and alpine dock is avoided by cattle and horses but readily eaten by goats and has been used as pig fodder in the past. In our study, we used cattle and pigs for only one season and this resulted in some suppression of alpine dock cover. Experience shows that the removal of alpine dock is very time consuming and not necessarily efficient, so it makes sense to implement preventive measures on mountain pastures to avoid its excessive spread. If, however, the alpine dock has overgrown and a preventive phase is no longer meaningful, it is necessary to choose the most appropriate method of removal.||