We determined how the interaction between geomorphic processes and vegetation development enables tipping points in braided rivers. We performed vegetation monitoring and succession modelling on the restored Kleblach side channel at the Upper Drava River (Austria) to assess long-term trends in vegetation succession and landform development. Two alpine pioneer plant species, the German Tamarisk (Myricaria germanica) and the Dwarf bulrush (Typha minima), were used to assess the ecosystem consequences of succession. Vegetation rapidly developed on initially open sites; 14 years after restoration, approximately 60% of the study area was characterized by stable succession phases. Even a major flood event in the near future would not reduce the dense vegetation cover. This indicates that a stable, dense vegetation cover can lead to a permanent transition from a dynamic braided to a stable single-channel river without major morphological changes, which we interpret as “biogeomorphic tipping point”. The result is a significant reduction in the indicator species’ habitats, preventing them from maintaining a resilient population in the long term. Thus, maintaining process regimes with high hydro- and morphodynamics is critical for preserving the valuable braided river ecosystems. The idea of “biogeomorphic tipping points” contributes to the process-based conservation and restoration of braided rivers globally.

Alpine peatlands play a crucial role in mountain watershed functions and services while supporting high biodiversity. Their reliance on cool and humid conditions makes them particularly vulnerable to climate change, including rising temperatures and decreasing precipitation, as well as human disturbance. Moreover, their carbon storage potential must be integrated into global climate models. However, alpine peatlands remain largely unrecorded, and their typically thin or absent peat layers leave their role as carbon reservoirs unclear. This study investigated carbon stocks in Platzertal, an alpine valley at 2,300 metres above sea level in the Ötztal Alps, Tyrol, Austria. The area features numerous small-sedge swamps spanning 7.11 hectares. The study site was divided into 143 sub-sites with an average area of 497 m². Peat volume, bulk density, dry weight and total organic carbon were analysed in 40 samples from these sub-sites. To achieve a comprehensive understanding of peat layer depth across the area, 666 plots were established to classify soil types and measure peat layers. The average peat layer depth was 11 cm, ranging from 5 to 100 cm. The carbon stock of the study area was calculated using the carbon density approach. The total area (7.11 hectares) of small-sedge swamp has a peat volume of 6,223 m³ and stores approximately 282 tons of carbon, equivalent to 1,036 tons of CO₂ in total or approximately 146 tons of CO₂ per hectare. These figures are significantly lower than those reported for other peatland regions, particularly the extensive boreal peatlands of the Northern Hemisphere. Our findings highlight that, whilst alpine peatlands have significant ecological importance and offer various ecosystem services, their contribution as soil carbon reservoirs is comparatively minor.

Riparian softwood forests support numerous ecological functions and high biodiversity. In the context of the LIFE+ Traisen project, a non-regulated new riverbed for the lower Traisen River (“New Traisen”) was created within an artificially lowered floodplain corridor. Using vegetation monitoring from 2014 to 2021, we determined (i) the role of Solidago gigantea in the establishment of softwood forests, (ii) the habitat parameters (such as flooding height, fine substrate layer thickness, and vegetation cover) that impact the establishment and growth of woody plants, and (iii) the successional phase at which woody plants become established, as well as the potential creation of new germination habitats. During early succession, the softwood species, as light-tolerant pioneer species, colonized the open sites together with S. gigantea and subsequently established a floodplain softwood forest. Unexpectedly, we observed negative forest development only when the S. gigantea cover exceeded 90%. Neither the habitat parameters nor S. gigantea cover significantly impacted tree occurrence. However, we highlight the need for optimum habitat parameters for softwood forest development in early succession phases, ideally before S. gigantea forms dense, monospecific stands. Tailored monitoring strategies are needed to guide the succession of such semi-aquatic habitats toward the development of the desired habitat type.