Contributed Session.
Lead Organizer: Patrick Fink, Helmholtz Centre for Environmental Research (patrick.fink@ufz.de)
Presentations
02:30 PM
RESPONSE OF FOOD WEBS TO STREAM RESTORATION (9327)
Primary Presenter: Markus Weitere, Helmholtz-Centre for Environmental Research - UFZ (markus.weitere@ufz.de)
Food webs represent the flux of matter within interacting communities. They are an ideal tool to assess the success of ecosystem restoration measures as they integrate structural and functional aspects of communities. Based on stable isotopes (δ13C and δ15N) of benthic invertebrates, we analyzed here the recovery of food webs after stream restoration with respect to hydro-morphology and waste water pollution. In a long-term dataset following up to 28 years after restoration, we could show clear responses of food web metrics to restoration. While the trophic similarity as a proxy for functional redundancy showed consistently positive relationships with time since restoration, the responses of other metrics such as food chain length and trophic diversity were less consistent over sites. Instead, they showed site-specific responses including both positive as well as negative trends with time since restoration. On that basis, we performed intense analyses of sites with different restoration ages including resource and consumer stable isotope analyses as well as consumer gut content analyses in order to detect mechanisms for the different responses. First results suggest that the prey diversity of higher trophic levels is significantly reduced in restored compared to near-natural sites despite long recovery times and recovery of overall taxa richness. Together with the strong restoration effects on trophic diversity, this underlines the value of food web analyses besides common community analyses to understand the conditions for full recovery of ecosystems.
02:45 PM
Linking small scale hydromorphology to biofilm’s biodiversity and functioning to explain restoration success (9114)
Primary Presenter: Julia Pasqualini, Helmholt Centre for Environmental Research-UFZ (julia.pasqualini@ufz.de)
Dams alter streams' hydromorphology, leading to habitat degradation and impacting biodiversity and ecological processes. Thus, dam removal aims to restore streams to a reference state. However, many ecological processes are mediated by biofilms, microbial communities associated with the streambed, which are influenced by physical processes occurring at spatial scales smaller than those targeted for restoration. This raises the question of whether restoration succeeds in restoring small-scale hydromorphology and if this results in a recovery of microbial diversity and functioning. Using a space-for-time substitution approach, we sampled 3 reaches of a 2nd-order stream in Germany: a dammed reach (impacted), a reference reach, and a restored one. We quantified biofilms’ functioning (DOC and NO3- uptake) and diversity (16S sequencing), and we measured small-scale hydromorphology (turbulent kinetic energy (TKE) and flow velocity (FV)). TKE and FV were lower in the impacted than in the reference reach. DOC uptake was higher in the impacted than the reference reach, while NO3- uptake did not differ. The microbial community differed significantly. Restoration effectively improved hydromorphology; on average, TKE and FV returned to the reference’s site levels. The microbial community's composition also recovered. An increase in TKE likely contributed to the partial recovery of DOC uptake; however, DOC uptake did not reach reference levels. Our findings suggest restoring biofilm’s biodiversity and functionality may only be possible by restoring also the small-scale hydromorphology.
03:00 PM
LINKING THE RECOVERY OF STREAM INVERTEBRATE COMMUNITY COMPOSITION AND ASSOCIATED ECOSYSTEM FUNCTIONALITY – IMPLICATIONS FOR RESTORATION SUCCESS (9120)
Primary Presenter: Patrick Fink, University of Cologne (patrick.fink@ufz.de)
Restoration approaches to improve the hydromorphology of streams are increasing worldwide, but often fail to recover biodiversity and ecosystem functionality. One reason might be that many restoration measures are undertaken at the reach scale, which may not be the relevant spatial scale for the activity invertebrates that mediate crucial ecosystem functions. Here, we investigate the relationship between the restoration of hydromorphology after dam removal in streams in Germany and Spain and the recovery of macroinvertebrate biodiversity and their associated ecosystem functions. Our data indicate that while restoration measures associated with dam removal are often successful in restoring animal biodiversity and community composition, this does not necessarily come with a complete recovery ecosystem functioning related to those organisms. As the recovery of functionality gains attention as a key objective of ecosystem restoration, a holistic perspective covering not only structural, but also functional variables is thus essential for evaluating the success or failure of restoration measures. Ultimately, understanding the linkages between hydromorphological heterogeneity, biodiversity and associated ecosystem functions is crucial for successful and sustainable restoration measures.
03:15 PM
Strategic wetland restoration for optimizing ecosystem services and climate impact (9208)
Primary Presenter: Emily Ury, Environmental Defense Fund (ury.emily@gmail.com)
Wetland restoration holds great potential as a nature-based solution to water quality, flood risk, and climate change; however carbon balance is not often considered in restoration prioritization. Spatial heterogeneity in wetland carbon sequestration and methane emissions potential leads to locations that are more or less favorable for restoration with respect to climate outcomes. Given widespread investments in wetland restoration, there is an urgent need to prioritize locations and practices that lead to the largest climate benefit, as well as synergies with other co-benefits. Using peatlands as a case study, we investigate the climate impact of different restoration prioritization strategies. We find strategic restoration of 30% of the world’s drained peatlands prioritizing GHG emissions reductions, would sequester 0.54 ± 0.20 Pg CO2eq. yr-1 more than the same magnitude of restoration conducted randomly. Meeting a 30% restoration target while prioritizing water quality improvements or flood risk mitigation is still beneficial for the climate, resulting in net emissions reductions of 0.32 ± 0.15 and 0.48 ± 0.19 Pg CO2eq. yr-1, respectively, and demonstrates opportunities for overlap between restoration objectives. We use spatially explicit projections of increasing wetland methane emissions due to climate change to account for methane emission growth by 2100. Our work highlights numerous opportunities for peatland restoration to simultaneously achieve both near- and long-term climate change mitigation as well as provide local-to-regional scale ecosystem services.
03:30 PM
ZOSTERA MARINA IN VITRO CULTIVATION TECHNIQUES AS A NOVEL APPROACH TO SEAGRASS RESTORATION (9154)
Primary Presenter: Sarah Merolla, Marine Biological Laboratory (smerolla@mbl.edu)
Zostera marina is a species of seagrass that acts as a vital ecosystem engineer in coastal areas. Z. marina meadows in Cape Cod, Massachusetts are rapidly disappearing due to a reduction in water quality and rising temperatures in the area. Many restoration efforts have been attempted with low success rates, prompting the need for new restoration approaches. Our study evaluated Z. marina cultivation techniques through a series of experiments. The first experiment assessed optimal conditions for Z. marina seedling cultivation in vitro. We tested the effects of media composition (biphasic vs. liquid media) and aeration techniques (bubbling vs. shaking) over four weeks. Biomass accumulation was used as the primary indicator of seedling performance. A second experiment examined how cultivation environments (in vitro vs. natural conditions) and donor populations (seeds collected from different sites in southeastern MA) impact Z. marina seed germination and development. Seeds collected from 13 sites were cultivated in culture chambers under sterile conditions or in seawater aquaria for six weeks. Seed cultivation success was evaluated based on germination rates and seedling survivability. The third experiment focused on the acclimatization potential of in vitro-cultivated Z. marina seedlings, comparing their survival rates in sterile culture and non-sterile seawater aquaria after 8 weeks. Results from these studies will contribute to the optimization of Z. marina cultivation protocols and inform seagrass restoration strategies.
03:45 PM
DEVELOPING CALLUS INDUCTION METHODS FOR ZOSTERA MARINA: A BIOTECHNICAL APPROACH TO SEAGRASS RESTORATION (9156)
Primary Presenter: Grace Dixon, Marine Biological Laboratory (gdixon@mbl.edu)
Zostera marina is a flowering seagrass vital to fisheries and coastal ecosystems. Population assessments over the past four decades have documented significant declines attributed primarily to thermal stress and cultural eutrophication. Current restoration initiatives aim to re-establish seagrass beds through both transplantation and direct seed dispersal methods. Restoration success remains constrained by limited seed availability and variable recruitment rates. This study aims to develop protocols for callus induction and somatic embryogenesis in Z. marina to enable the production of somatic embryos from a single seed, thereby scaling up restoration efforts. Experimental protocols have been designed for wild explant sterilization, aseptic seedling culture, in-vitro germination and callus induction, with eventual transfer to studies on somatic embryogenesis. In comparison to other liquid media prepared for germination of seeds, rates in culture reached up to 85% with basal f/2 media. Seedlings grew up to three leaves with a maximum leaf height of 4.5 cm after 4 weeks in culture. Varying types and concentrations of growth hormones in agar media were used in callus induction trials, as well as axenic and wild explant tissue from seagrass. Preliminary results demonstrate potential callus development in root structures and immature seeds. These findings represent a crucial step towards large-scale propagation of Z. marina for ecosystem restoration purposes.
CS17 - Restoration
Description
Time: 2:30 PM
Date: 27/3/2025
Room: W207CD