Effect of the Gabčíkovo Waterworks (Slovakia) on riparian floodplain forest ecosystems in the Danube inland delta: vegetation dynamics and trends

Abstract

Human alteration of watercourses is global phenomenon that has had significant impacts on local ecosystems and the services they provide. Monitoring of abiotic and biotic changes is essential to mitigating long-lasting effects, and the 23-year dataset from the Gabčíkovo Waterworks provided a rare opportunity to assess the impact of groundwater regimes on vegetation. The main aim of this study was to describe the effect of the Gabčíkovo Waterworks on vegetation structure and species composition of the adjacent riparian floodplain forests over the past 23 years. The results are based on studies of three permanent monitoring plots (PMPs) located in the Danube inland delta – two outside (PMP 1 and 3) and one (PMP 2) fully under the influence of the artificial supply system. Our results demonstrate that the Danube inland delta was negatively affected by the Gabčíkovo construction, particularly for sites outside of the artificial supply system. There was a significant decrease in soil moisture and increase in nitrogen at both external PMPs (1 and 3). Alter soil conditions were accompanied by negative changes in plant species composition demonstrated by decreases in the number of typical floodplain forest species that are characteristic for the alliance

Managing floodplains using nature‐based solutions to support multiple ecosystem functions and services

“…Restoration of the Danube floodplain in Slovakia is perceived as an important factor in improving environmental values, as it is a highly anthropogenically modified area. Major interventions in this area include, for example, the construction of the Gabčíkovo waterworks, leading to a slow degradation of rare and endangered habitats of softwood floodplain forests in the Danube inland delta—see Figure 3 (Petrášová‐Šibíková et al, 2017).…”

Multifunctional Use of Agricultural Land with Support for Selected Ecosystem Services in the Territory Protected Water Management Area Žitný Ostrov

“…It has led to changes in the original composition of plants and animal communities and slow degradation of the riparian floodplain forests due to the reduced amount of floodwater entering the channel systems of wetland ecosystems. The current artificial flooding system cannot fully replace previous natural floods in the Danube inland delta, and it is also insufficient for the restoration and preservation of the optimal moisture conditions in the softwood floodplain forests, which would be similar to the pre-operation period of the Gabčíkovo Waterworks [56]. Currently, research, restoration, and management of biotopes are being addressed by several research institutions and conservation associations, for example, through LIFE Restoration and Management of Biotopes projects.…”

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

“…In recent decades, the construction of the Gabčíkovo dam (finished in October 1992) has been the most significant intervention to the Danube inland delta. The management of water levels for the original channel system is insufficient, almost completely lacking floods, and consequently, forests are degrading continuously [21].…”

“…Crucial elements of resilience in riverine systems are linkages: lateral linkage-between the floodplain and channel, longitudinal linkage-upstream and downstream river channel and vertical linkage-between channel and riverbed [40]. The building of the Gabčíkovo dam limited all linkages and caused the cut-off sedimentation, the deepening of the riverbed and thus the decline of groundwater tables and restricted the recruitment of indigenous species, which potentiates the incursion of alien species [21,41].…”

“…The assessment of vegetation change over time is important to better understand the effects of the different drivers of vegetation changes [19], as well as invasions [13,20,21]. In habitats with long-lived species, e.g., forests, such studies are important to monitor the long-term changes of vegetation, though vegetation dynamics in these habitats are often inherently slow [19].…”