Establishment and survival of three invasive taxa of the genusReynoutria (Polygonaceae) in mesic mown meadows: A field experimental study

Abstract

The effect of traditional management on the initial phase of invasion into mesic mown meadows was studied in the Kfivokl~tsko protected landscape area in Central Bohemia, the Czech Republic. In 1996, rhizome fragments of alien species native to Asia, i. e. Reynoutria japonica, R. sachalinensis and their hybrid R. xboheraica were planted in experimental plots and their establishment recorded. Established plants were then subjected to the following six treatments which simulated the management practices traditionally used in the study area: mowing twice a year, grazing by goats and sheep separately at two different intensities, and a control plot. Plant survival was recorded in the two years following planting. In order to compare the effect of the growing period, the experiment with R. japonica was conducted in two subsequent years (1995 and 1996) thus allowing observations over three years on this species. The experiment was carried out in two sites (meadows), with three blocks of treatments established in each. Significantly better establishment was found in R. japonica and R. xbohemica than in R. sachalinensis. Survival of all three taxa was negatively effected by all the management treatments applied (P < 0.001). In control plots with plants of all three taxa, there was virtually no mortality during the growing seasons of either year and the number of surviving plants decreased only in the winter. In the former two species, 38.5 + 19.4% of plants survived the first winter, the corresponding figure for the latter being only 7.2 ± 6.1%. It can be concluded that traditional management provided it is applied continuously may represent an effective barrier against the invasion of the Reynoutria species. Once ceased, the potential for invasion increases and if invasion occurs, special control measures are required to eliminate the invading plants effectively.

Potential phytotoxic and shading effects of invasive Fallopia (Polygonaceae) taxa on the germination of native dominant species

“…The weakest phytotoxic suppressor was F. japonica; its effect on both native dominants was generally lower than that of its two congeners, and higher phytotoxic concentra tion often did not result in a more pronounced effect. The weak phytotoxic effect of F. japonica corresponds to generally lower regeneration and competitive ability of this species, compared to the other two Fallopia taxa (Brabec and Pyšek 2000). The most profound inhibitory effect was found for F. sachalinensis, which reduced namely the germination of U. dioica.…”

“…The two target species tested, Urtica dioica and Calamagrostis epigejos, are among the most expansive native species in the Czech Republic (Prach and Wade 1992), dominating in riparian and ruderal habitats where Fallopia taxa often invade (Pyšek and Prach 1993;Brabec and Pyšek 2000). Both C. epigejos and U. dioica are competitively strong rhizomatous perennials forming large stands, but they also produce large quantities of seed (Prach and Wade 1992).…”

“…The effect of phenolic compounds is higher in early spring (Lohdi 1975) and for Fallopia species, early seasonal development is typical (Marigo and Pautou 1998). In temperate conditions of Central Europe, Fallopia quickly builds a dense leaf canopy from April to May (Brabec and Pyšek 2000).…”

“…var. japonica and their hybrid F. ×bohemica (Chrtek & Chrtková) Bailey, are rhizomatous herbaceous perennials producing a large amount of biomass (Brock 1995;Horn and Prach 1995) and large leaf area (Brabec and Pyšek 2000). They invade along water courses, in waste sites and other disturbed areas (Pyšek et al 2001(Pyšek et al , 2002Pyšek 2009).…”

Do Landscape Structure and Socio-Economic Variables Explain the Solidago Invasion?

“…At the regional scale, however, considerable variation between habitats in the number of alien species that they harbour has been observed (Chytrý et al 2005(Chytrý et al , 2008aThiele et al 2009;Chmura et al 2013;González-Moreno et al 2014). Such differences are explained by (a) variation between ecological requirements of alien species and the available niches in the invaded area and (b) differences in the inherent susceptibility of habitats to invasion (Lonsdale 1999;Brabec and Pyšek 2000;Shea and Chesson 2002;Chytrý et al 2008a,b;Fukami et al 2013).…”