Long-Term Changes of Softwood Floodplain Forests—Did the Disappearance of Wet Vegetation Accelerate the Invasion Process?

Abstract

Objectives: We followed the long-term changes of softwood floodplain forests strongly altered by water regime changes and examine the behaviour of neophytes in this environment. Here we ask: (1) How did the composition of neophyte and native species change? (2) How did the presence of species that prefer wetter conditions change? (3) What traditionally distinguished type of softwood floodplain forests (a wetter one or a more mesophilous one) do neophytes prefer? (4) What environmental factors affect the native species richness and the occurrence and cover of neophytes? Materials and Methods: Historical and recent phytosociological relevés of the association Salicetum albae of the Slovak part of the inland delta of the Danube River were used (177 plots together). For each plot, the number and cover of neophytes and number of native species were measured, and the Shannon-Wiener diversity index, the stand structure (cover of tree, shrub and herb layer) and the mean of Ellenberg indicator values were calculated and compared among time periods. Temporal trends of the soil moisture characterized by indicator values calculated for each plot were determined using a Linear Model. The synoptic table of traditional vegetation types was done to show preferences of neophytes for particular softwood forest types. The effect of site conditions on native species richness and occurrence of neophytes was determined using the Generalized Linear Model. Results: The relative number and cover of neophyte species increased and the absolute number of native species decreased over time; the vegetation of the area has changed from variable hygrophilous and mesophilous to homogenised mesophilous; most non-native species prefer the mesophilous vegetation of the floodplain forests; the wetter parts of the floodplain more successfully resisted invasions. Conclusions: The vegetation of the researched area has considerably changed over time to become less diverse and less hygrophilous, and has more invasive species. To preserve floodplain forests, natural hydrological and connectivity patterns should be adequately protected.

The Impact of Climate Change and Regulation of the Water Regime on the Morphological Structure of the Floodplain Forests in Petržalka, Slovakia

“…They discovered these changes were mainly caused by the disturbance of the water regime. They concluded that, during the period monitored, there was a decline in autochthonous species and an increase in neophytes, which are slowly dominating domestic species (Mikulová et al, 2020).…”

“…According to the results of the National Forest Inventory and Monitoring (NIML) of the Slovak Republic, which also included the so-called "white areas" (forests on non-forested land), Slovakia's forest cover is up to 44.3 ± 0.4%, which is positive, but they do not reflect the structural changes that have occurred during that period (Ministry of Agriculture and Rural Development of the Slovak Republic, 2010). Mikulová et al (2020) has stated that in the last 60 years, soft floodplain forests have been transformed considerably. The plant composition points to the indirect intervention of…”

Extremes Rainfall Events on Riparian Flora and Vegetation in the Mediterranean Basin: A Challenging but Completely Unexplored Theme

“…Specifically, riparian vegetation, e.g., floodplain vegetation or vegetation directly adjacent to rivers and streams, influences several ecological functions of aquatic habitats, such as providing food, moderating stream water temperature by evapotranspiration and shading, providing a buffer zone that filters sediments and controls nutrients, and stabilizes stream banks [72,74,80,81]. Moreover, riparian zones represent key systems for regulating aquaticterrestrial linkages [72,74,82,83] which may provide early indications of environmental change [74,84,85].…”

Forest managers’ perspectives on environmental changes in the biosphere reserve Mura-Drava-Danube

“…Changing climate results in a higher frequency and intensity of disturbance events such as storms (Beniston et al, 2007), droughts (Dubrovský et al, 2014;Hanel et al, 2018;Seidl et al, 2017), and floods (Arnell and Gosling, 2016;Dottori et al, 2018;Winsemius et al, 2016), influences habitat suitability for local forest communities (Dyderski et al, 2018), and alters interactions between pests and diseases (Bentz et al, 2010;Jönsson et al, 2009). Furthermore, globalization favors the accidental spread of non-native species (Hulme, 2009;Meyerson and Mooney, 2007;Mikulová et al, 2020) which include pests and diseases that endanger forest tree species and biodiversity (Boyd et al, 2013) as well as non-native plants (Allard and Sigaud, 2005;Nisbet et al, 2015) that create competitive pressure on native plant communities (Nadal-Sala et al, 2019). Both impacts were found to go beyond the capability of native species and ecosystems to resist (Hansen, 2008).…”