Restoration Measures Research Articles

Effects of Land Use Change on Soil Aggregate Stability and Erodibility in the Karst Region of Southwest China

Differences in land use type and chronological age affect soil properties and plant community characteristics, which may influence soil structural stability and erodibility. However, knowledge on the effects of soil physicochemical properties on soil aggregate stability and erodibility at different land use years is limited. This study selected five land use types: corn field (Year 38th-y), corn intercropped with cabbage field (Year 38th-y + b), fruit and meridian forest (Year 6th-jgl), naturally restored vegetation (Year 6th-zr), and artificial forest (Year 7th-rgl) in the karst landscape of the Chishui River Basin in Yunnan Province. We aimed to identify the influencing factors of soil stability and erodibility under different land use time series. The results indicated that the mean weight diameter (MWD), the geometric mean diameter (GMD), and soil structural stability index (SSI values) were highest in Y6th-zr and lowest in Y7th-rgl. Conversely, the erodibility K value was lowest in Y6th-zr, suggesting that the soil structure in Y6th-zr exhibited greater stability, whereas soil stability in Y7th-rgl was lower. Redundancy and throughput analyses revealed that organic carbon and water-stable aggregates > 2.0 mm content had higher vector values. Soil bulk density, total nitrogen, organic carbon, and soil texture content were the main factors contributing to soil stability variation (0.338–0.646). Additionally, total nitrogen, organic carbon, total phosphorus, and soil texture content drove the variation in K values (0.15–1.311). Natural vegetation restoration measures can enhance soil structure to a certain extent. These findings highlight changes in soil aggregate stability and erodibility over different land use durations. The research results have important theoretical and practical significance for understanding the differences in soil erosion and soil restoration under different land use patterns in the karst landscapes of southwest China.

Ecology and Sustainable Conservation of the Nase, Chondrostoma nasus: A Literature Review

Cyprinid fish play a major role in riverine ecosystems because of their high abundance, variety of life-history patterns, and habitat requirements. The nase (Chondrostoma nasus) is an algivorous, rheophilic, lithophilic, and oxyphilic species and is very pollution-sensitive. Thus, it represents a good indicator for habitat quality in the lower rhithral and upper potamal zones of the European river system. Due to its high level of ecological requirements, the species is very sensitive to human disturbance, leading to habitat loss and river fragmentation, climatic disruption causing a modification of hydrological and thermal regimes, organic and inorganic chemical water pollution, as well as sediment deposition. Its populations are declining in most of its distribution areas. This paper aims to synthesise the scientific knowledge on the different aspects of the nase ecology thanks to consultation of the scientific literature by addressing the following themes: European repartition, morphology and identification, reproduction and life cycle, diet, movement dynamics of adults and juveniles, and the characteristics of spawning grounds and habitats of juveniles and adults. We also provide an overview of the impact of human activities and climate shifts on natural ecology and conservation and present restoration measures based on the results of some studies that have successfully improved their habitats and/or preserved their populations. A series of key research questions are identified that should stimulate new research on this species as well as conservation measures for sustainable conservation. This paper may be particularly of interest to researchers in aquatic and fisheries sciences, river managers, and environmental conservationists.

Research on ecological restoration and its impact on society in coal resource-based areas: Lessons from the Ruhr area in Germany and the Liulin area in China

The coal resource-based areas rely on coal resources and primary processing as their pillar industries, such as the old industrial areas in China and Germany. Long-term, large-scale coal mining has significantly damaged the ecological environment of mining areas. Environmental restoration refers to repairing, rehabilitating, or revitalizing ecosystems that have been degraded, damaged, or destroyed by human activities or natural disasters. In fact, ecological restoration is not just an environmental issue and it is a societal problem. Ecological restoration is closely linked to natural resources, the environment, the economy, society, and politics. These factors form a social ecological system and it is the basis for local stability and sustainable development in the coal resource-based areas. In this process, the relationship between government, enterprise, and local people is constantly being reshaped and defined, then it causes changes in the local social ecology and political ecology. The paper researches the Ruhr area in Germany and the Liulin County in China, the former is a world-famous old industrial and the latter is a typical coal mining subsidence district. By analyzing and comparing the ecological restoration and significant social changes in the Ruhr area and the Liulin County at different periods, the findings show the unique ecology— social system of the coal resource-based area, then enhances the effective measures for ecological restoration and sustainable development of the coal resource-based areas.

TECHNOLOGY OF STRUCTURAL REPAIR OF CONCRETE AND REINFORCED CONCRETE STRUCTURES OF WATERWORKS

The assessment of the current state of the water and land reclamation engineering infrastructure facilities, which was carried out on the basis of the analysis of technical documentation, visual, and instrumental examination of the structures' technical condition, confirms that as a result of long-term operation of the waterworks without proper reparation and restoration measures, their technical condition has significantly deteriorated. The most promising for the repair of concrete and reinforced concrete structures are cement-based materials modified with polymers (polymer concrete), which are dry mixtures of cement, sand, re-dispersible polymer powder (RPP) and other modifying additives. The research results of the redispersing polymer powders influence on the adhesive properties of repair composites are presented. It is shown that the modification of cement-sand solutions of RPP leads to a significant increase in the adhesive properties of repair composites. The optimally effective concentration of RPP in repair compositions has been found. The article highlights the technology of structural repair of concrete and reinforced concrete structures of the waterworks with the use of modern composite materials, which makes it possible to restore the design geometric indicators and the load-bearing capacity of the structures. The proposed technology and effective repair compositions help to carry out repair and restoration work on hydrotechnical structures of the water management and reclamation complex, in particular those destroyed or damaged as a result of the military aggression of the Russian Federation against Ukraine. The main principles of choosing the optimal technology for the structural repair of concrete and reinforced concrete structures of the waterworks, depending on the nature and degree of damage, the influence of technological and operational conditions on the structures' geometric indicators restoration during the modernization and reconstruction of reclamation systems in the post-war period, are revealed.

Hysteretic and asynchronous regime shifts of bacterial and micro-eukaryotic communities driven by nutrient loading

Nutrient pollution is pervasive in many urban rivers, while restoration measures that reduce nutrient loading but fail to improve biological communities often lack effectiveness due to the indispensable role of biota, especially multi-taxa, in enhancing ecosystem stability and function. The investigation of the response patterns of multi-taxa to the nutrient loading in urban rivers is important for the recovery of biota structure and thus ecosystem function. However, little is known about the response patterns of multi-taxa and their impact on ecosystem structure and function in urban rivers. Here, the study, from the perspective of alternative stable states theory, showed the hysteretic response of both bacterial and micro-eukaryotic communities to nutrient loading based on the field investigation and environmental DNA metabarcoding. Bistability was shown to exist in both bacterial and micro-eukaryotic communities, demonstrating that the response of microbiota to nutrient loading was a regime shifts with hysteresis. Potential analysis then indicated that the increased nutrient loading drove regime shifts in the bacterial community and the micro-eukaryotic community towards a state dominated by anaerobic bacteria and benthic Bacillariophyta, respectively. High nutrient loading was found to reduce the relative abundance of metazoan, but increase that of eukaryotic algae, which made the trophic pyramid top-lighter and bottom-heavier, probably exacerbating the degradation of ecosystem function. It should be noted that, in response to the reduced nutrient loading, the recovery threshold of micro-eukaryotic communities (nutrient loading = ∼0.5) was lower than that of bacterial communities (nutrient loading = ∼1.2), demonstrating longer hysteresis of micro-eukaryotic communities. In addition, the markedly positive correlation between the status of microbial communities and N-related enzyme activities suggested the recovery of microbial communities probably will benefit the improvement of N-cycling functionality. The obtained results provide a deep insight into the collapse and recovery trajectories of multi-trophic microbiota to the nutrient loading gradient and their impact on the N transformation potential, therefore benefiting the restoration and management of urban rivers.

A methodological study on the identification of ecological security change processes and zoning control strategies —— Based on the perspective of sustainable development

Ecological security (ES) is a crucial indicator for assessing the sustainable development of a region. Currently, most studies on ES primarily focus on process analysis, and the integration of environmental variability into the development of tailored control strategies for regions with varying ecological quality is overlooked. Therefore, in this study, we identified regional ES change processes, employed an optimized system to calculate the ecological security index (ESI), and identified ecological corridors (ECs) through the Minimum Constrained Resource (MCR) model to determine zoning strategies for typical arid regions, using the Ningxia region in the Yellow River Basin of China as an example. The findings showed that (1) from 2006 to 2020, the ESI values of most regions were between 0.2 and 0.4, with small but consistent increases in the ESI values over the years. (2) The proportion of regions with high ES ratings increased by 9.08 % across all districts and counties, and the center of gravity of ES shifted in a north–south and east–west direction. (3) The ESI exhibited a strong positive spatial correlation, characterized by spatial diffusion and spillover effects in most regions. (4) The ECs were predominantly distributed in a north–south direction, involving a total of 20 districts and counties. Based on the principles of sustainable development, we developed a model for the dynamic identification and zoning control of regional ES, aiming to provide a practical framework for effective ecological restoration and protection measures. Additionally, the strategies and methodologies presented in this study serve as important references for similar regions worldwide to facilitate the zoning control of ES, highlighting the broader significance and applicability of the study.

Climate change mitigation potential of restoration of boreal peatlands drained for forestry can be adjusted by site selection and restoration measures

Peatland restoration is seen as a key nature‐based solution to tackle climate change and biodiversity loss. In Europe, nearly 50% of peatlands have been drained during the last decades, which have shifted their soils to carbon dioxide (CO2) sources. Soils of forestry‐drained peatlands are known to vary from CO2 sources to small sinks depending on their fertility and wetness. When peatlands are restored, it can be expected that rates of CO2 and methane exchange will vary depending on site fertility and wetness. We generated seven restoration pathways with different starting and end points and assessed the climate impacts of them. The GHG emission coefficients were compiled from literature, and radiative forcing was calculated for a 500‐year time period since restoration. All seven restoration pathways improved carbon sink capacity; however, the climate impact differed from cooling to warming. The highest cooling impact occurred in a pathway leading from nutrient‐rich drained peatlands toward tree‐covered spruce or pine mires. Warming impacts occurred in a pathway leading from nutrient‐poor drained peatlands toward open peatlands. The results of this study can be used to help identify peatland sites and restoration targets to maximize climate change mitigation from restoration. In practice, however, restoration has to fulfill other targets, such as biodiversity safeguarding, improvement of hydrological conditions, and socio‐economic aspects. Fulfilling all targets simultaneously requires compromises on all targets.

Деятельность организационно-инструкторского отдела Ленинградского городского Совета депутатов трудящихся в 1943–1945 гг.

The activities of the Organizational and Instructional Department of the Leningrad City Council during the war and blockade have not previously been subjected to detailed study. The significance of this scientific problem is, first of all, due to the role of instructors, which they played in organizing and monitoring the implementation of regulatory decisions of the Leningrad City Executive Committee, as well as resolutions of local and central party authorities. The article reconstructs the main approaches to the work of an instructor in 1943–1945, identifies the most significant areas of activity, analyzes the problems of the functioning of Department and practical steps to solve them. During the period under study, the key vector of activity of the Leningrad City Executive Committee was the implementation of restoration measures in Leningrad. The study introduces into scientific circulation regulatory and records materials deposited in the Central State Archives of St. Petersburg. By reconstructing the main approaches to instructor work, analyzing key directions of activity, and evaluating challenges and solutions, this article sheds light on the multifaceted dynamics of governance amidst the exigencies of war and blockade.

Species specific responses to stressors hamper Trichoptera recovery

Worldwide, aquatic biodiversity is severely threatened as a result of anthropogenic pressures such as pollution, habitat destruction and climate change. Widescale legislation resulted in reduced nutrient- and pesticide loads, and restoration measures allowed modest recovery of freshwater biodiversity. However, from 2010 onwards, recovery in the otherwise unrestored aquatic habitats stagnated. The aim of the present study was therefore to reveal long-term trends in aquatic biodiversity in an anthropogenic landscape and to explain the observed patterns. To this end, over 40 years of biomonitoring data of the indicative taxa group Trichoptera (caddisflies), with an exceptionally high spatial and temporal resolution, was employed. Periods of recovery, stagnation, and decline were delineated using linear and non-linear modelling approaches. Subsequently, species were grouped based on abundance patterns over time and this grouping was used to ascertain species-specific responses to anthropogenic stressors using a trait-based approach. Richness and abundance of all Trichoptera jointly, as well as of the five most abundant and the remaining 136 species, significantly increased from 1980 to significant breakpoints from 2010 onwards, after which these metrics, except the abundances of the 5 most abundant, declined significantly. Trend-based species groupings were not significantly explained by biological traits or ecological preferences. However, Trichoptera species increasing in abundance were less sensitive to climate change and poor water quality, or concerned sensitive species which benefited from restoration measures. Species with stable or declining abundances showed higher sensitivity to climate change. The Trichoptera declining in abundance indicated that conditions in non-protected or restored habitats did not improve due to climate change on top of the other anthropogenic pressures. These observations reinforce the need for increased efforts to improve the only moderately restored water- and habitat quality in anthropogenic landscapes to halt further aquatic ecosystem degradation and to turn biodiversity losses again into recoveries.

Bridges Between Soil Restoration, Land Management and Community Involvement in the Great Green Wall of Mauritania: A Preliminary Study

In the Sahel, land ownership is significantly influenced by the complexity of hierarchical, ethnic, and tribal aspects as well as communal, religious, and state rights. This complicates the development of large-scale ecological projects. This study investigates the positive and negative experiences that have changed the method and attitude of agencies in Mauritania to providing a holistic and ecosystemic approach to conservation and restoration. The physical environment and society’s perception of applied restoration measures are of great importance for reducing environmental degradation and promoting future actions. Interviews with stakeholders helped understand the social reality and impact of restoration and management measures taken on the communities. The results of this study revealed that measures such as fencing plots, preventing the passage of livestock, and stabilizing sand dunes noticeably improved the vegetative cover of the soil in the Sahel. This improvement in vegetation cover has had direct effects on the improvement of soil quality indicators such as organic carbon content, pH, soil structure, color, and texture. Different stakeholders have shown considerable involvement in projects, positively valuing their implementation and observing improvements in their daily lives.

Disentangling the roles of bracken fronds and litter on natural seedling recruitment in fire-disturbed tropical montane habitats

Tropical montane forests are diverse ecosystems often affected by uncontrolled human-induced fires causing tree mortality and creating large deforested areas. After fires, Pteridium spp. ferns (bracken) often dominate, and forest regeneration in these areas is slow. In this study, we evaluated the effects of bracken fronds and litter, as well as the micro-environmental conditions created by the fern, on the density and species diversity of naturally recruiting seedlings. At eight sites, 120 experimental plots were established among forest and bracken-dominated areas with the following treatments: (a) fronds and litter intact (F+L+); (b) fronds intact and litter removed (F+L-); (c) fronds removed and litter intact (F-L+); and (d) fronds and litter removed (F-L-). After one year, all seedlings were registered, identified and classified according to their life-form (tree, shrub, herb, vine), dispersal vector (wind- or animal-dispersed) and successional status (early-, mid-, and late-successional). For all treatments we assessed 12 micro-environmental variables. We identified 3649 naturally-recruiting seedlings corresponding to 278 species from 70 families. We found positive effects of bracken fronds particularly on tree seedling recruitment: treatments with fronds had greater densities of both animal- and wind-dispersed tree seedlings, 1.8 and 1.4 fold higher, respectively, compared to treatments without fronds. Similarly, the density of early-, mid- and late-successional tree species was 1.3, 1.7 and 1.9 times higher in treatments with than without fronds. Furthermore, species diversity of early-, mid- and late-successional tree species was higher in the treatments with fronds. The environmental conditions generated by bracken presence, such as photosynthetically active radiation, soil temperature, live bracken biomass and litter depth, had positive effects on seedling density of all, animal-dispersed and early-successional tree species, and negative effects on seedling recruitment of other life-forms, notably from early successional stages. To promote forest regeneration in bracken-dominated areas, active restoration measures such as direct seed addition and transplants of nursery-raised seedlings of mid- and late-successional species should be considered. Since bracken can hinder the establishment of some life forms and species but favor others, it is recommended to include a trait-based approach to understand species responses to environmental factors and select species that are optimally adapted to bracken-dominated habitat conditions to promote forest regeneration.

Temporal and spatial trends of imidacloprid-related hazards in France

Neonicotinoids are the top-selling insecticides worldwide. Because of their method of use, mainly to coat seeds, neonicotinoids have been found to widely contaminate the environment. Their high toxicity has been shown to be a major concern in terms of impact on biodiversity, and the use of these insecticides has been associated with population declines of species in different countries. Despite the widespread recognition of the risk of neonicotinoids to biodiversity, their temporal and spatial use remains poorly known in many countries. Yet this information is essential to address the potential impacts of these pesticides on biodiversity and to inform measures to establish protected areas or biodiversity restoration. The present study relied a large publicly available dataset to characterise the temporal and spatial use in France of imidacloprid, the most widely used neonicotinoid worldwide, as well as analysed water contamination surveys between 2005 and 2022 to assess the contamination of the environment. The results show that imidacloprid was the main neonicotinoid used in France over the study period. This use was spatially structured, with higher use in northern and western France, particularly related to cereal and beet crops area. The water contamination survey indicated that imidacloprid has widely contaminated the environment and consequently increased the risk to biodiversity, especially in counties crossed by the Loire, Seine and Vilaine rivers. This risk increased between 2005 and 2018 due to the higher use of imidacloprid and decreased sharply after 2018 due to its ban, although it was reauthorized by derogation for sugar beet in 2021. This study is the first assessment of imidacloprid pressure on biodiversity in France and shows the spatial and temporal correlation between agricultural practices and the freshwater contamination level. These results will help to identify priority areas for mitigation and restoration measures.

Quantifying heavy metal and radionuclide contamination in fish and water proximal to a uranium tailings facility: A Linshui River basin investigation, China

BackgroundThe objective of this study is to evaluate the concentrations of heavy metals and radionuclides in water and fish samples collected from six designated sampling stations along the Linshui River, in close proximity to a Uranium Tailing Pond situated in China. Additionally, it seeks to estimate the bioaccumulation of heavy metals and conduct risk assessments, both carcinogenic and non-carcinogenic, for consumers. MethodsWater and fish samples (yellowhead catfish and common carp) were systematically collected from six stations along the river from January to June 2023, adhering to ethical standards and standard protocols for assessing water quality. Samples underwent chemical preparation and analysis for heavy metals using Graphite Furnace Atomic Absorption Spectrophotometry and Cold Vapor Atomic Absorption Spectroscopy, and for radionuclides using gamma spectrometry, with all methods validated for accuracy. ResultsThe water samples showed metal and radionuclide concentrations within acceptable limits, except for higher levels of U and Th compared to background values. Heavy metal concentrations were higher in common carp compared to yellowhead catfish, with both species exhibiting a similar trend. While non-carcinogenic health risk, as indicated by target hazard quotients, was low for consumers, the health risk data emphasized the carcinogenic threats posed by U238 and Th234. ConclusionsThe study highlights the importance of implementing comprehensive river restoration measures. Additionally, the bioconcentration factor values indicate minimal accumulation of heavy metals in the muscle tissue of fish.

Numerical modeling of bamboo fences with various infill porosities deployed for mangrove restoration

As part of mangrove restoration initiatives eco-friendly fence has been implemented in eroded coastal areas in recent years. These fences provide the capacity to mitigate incoming wave energy and facilitate sediment deposition, thereby promoting the establishment and maintenance of mangrove habitats. Nevertheless, it is crucial to investigate the influence of the infill porosity on the wave dissipation performance of these fences, as the infill porosity can vary considerably across different restoration projects. The aim of this research is to explore the relationship between the infill porosity and wave dissipation effectiveness to identify more efficient designs for these eco-friendly restoration measures. The experiments involving wave interactions with fence models were conducted in a wave flume measuring 0.8 m in width and 25 m in length. Four wooden fences with distinct infill porosities ranging from 0.60 to 0.90 were strategically positioned to assess wave transmission, reflection, and dissipation phenomena under 18 distinct wave conditions. Additionally, the simulating waves till shore (SWASH)model was employed to calibrate critical bulk drag coefficient parameters and simulate the flow velocity distribution surrounding the fences under the experimental wave conditions. The findings indicated that a fence with a reduced infill porosity exhibits a higher wave transmission coefficient. However, this is accompanied by a higher reflection coefficient and lower wave energy dissipation within the fence. Both the infill porosity and incident wave conditions influence the flow velocity distribution characteristics in the vicinity of the fences. The area where the interaction between waves and fences is the most prominent is concentrated in the upper water layer immediately adjacent to the frontal section of the fences. Understanding the velocity distribution and hydrodynamic characteristics of the fence area aids in better determining the suitable porosity of fill materials for engineering applications.

Bottom sediments as an indicator of the restoration potential of lakes—a case study of a small, shallow lake under significant tourism pressure

The study covered a small, shallow lake, intensively used for recreation (sailing, tourist services and port infrastructure). This study aimed to determine the spatial differentiation of bottom sediments and the potential for phosphorus release in five zones, differing mainly in the type of recreation, depth, direct catchment management, shoreline management and macrophyte presence. The results were used to propose protective and restoration measures to improve the water quality of the studied lake. The innovation in the study was the detailed analysis of bottom sediments, which can be a significant source of pollution besides the external load from the catchment and tourist pressure, in the planned management of this ecosystem. Examination of the physicochemical properties of the bottom sediments showed a clear variation in both composition and potential for internal phosphorus loading. The sediments from the profundal zone, where the most boating activity was observed, together with the sediments from the shallow zone where the boats dock (mooring zone), had the highest potential to supply phosphorus to the bottom waters. This fact was demonstrated by the highest total phosphorus (TP) concentrations in sediments (up to 1.32 mgPg−1 DW) and the content of the most mobile fractions (up to 33%). The other zones associated with the marina, fuel zone, tributary and canal were not significant sources of phosphorus to the ecosystem. Based on the above results, a restoration method involving the removal of bottom sediments from the bottom zone was proposed, supported, of course, by protective measures in the catchment (maintaining a buffer zone around the lake and limiting the inflow of pollutants with tributary waters). The proposed measures with sustainable tourist pressure should improve water quality and thus contribute to protecting this valuable natural landscape.

Restorative justice for adult offenders in South Australia: judicial perspectives and insights

ABSTRACT Restorative justice seeks to address harms arising from criminal conduct, with a focus that extends beyond punishment. While Australia has embraced restorative justice practices for young and Aboriginal and Torres Strait Islander offenders, programs for adult offenders have been comparatively slow to progress. Despite the reliance on judicial officers as the primary referral mechanism, there is limited research examining their views of restorative justice, particularly in the context of adult offenders. This paper presents the findings from a survey and interviews with judicial officers in one Australian jurisdiction: South Australia. There was clear support for restorative justice measures for adult offenders for a broad range of offences. Some concerns were raised with respect to victims’ safety, and the additional time and resources that restorative justice expends. Overall, the study found that the judicial officers who participated would welcome the introduction of a restorative justice program for adult offenders. With this support, and the potential benefits of restorative justice for victims, offenders, and the community, South Australia should consider extending its restorative justice offerings to adult offenders.

An evaluation of small river restoration using transient river habitat modelling for macrozoobenthos

The mandate to maintain at least a good ecological status of all surface waters has led to increased river restoration projects across Europe in the past two decades. The aim is to re-establish the hydromorphological situation and reverse the damage to freshwater ecosystems. In this study, we evaluated the restoration measures in a small stream in the State of Saxony, Germany, using the Transient River Habitat Modelling for Macrozoobenthos (TRiMM). The model was established using the Physical habitat template, covering physical habitat variables (flow, substrate, and thermal regime). It also introduces the application of a fuzzy approach to investigate river physical conditions and their effects on biological indicators like macrozoobenthos. Three taxa, namely Ancyls fluviatilis, Ephemera danica, and Gammarus fossarum, with different habitat preferences, were used to investigate the river’s ecological conditions. The model simulated the natural flow conditions from spring to summer, before and after the restoration was implemented. The research indicated that the restoration of the studied river sections succeeded in providing suitable habitats for target taxa at varied discharge conditions.

Mangrove extent reflects estuarine typology and lifecycle events

Ecosystem services provided by mangrove forests are increasingly recognised worldwide. These values have led to numerous ecosystem protection and restoration measures, including recent blue carbon economic incentives to re-establish mangroves at scale. However, our current ability to predict mangrove extent is based mainly on inundation averages (e.g. hydroperiod) or tidal planes of mature mangrove forests. This study investigates the validity of existing methods to accurately predict mangrove extent by comparing the location of existing mangroves at 27 sites (in 23 estuaries in southeast Australia) against commonly used approaches. To this aim, the downslope and upslope surface elevation limits of the mangrove species Avicenna marina were measured on-site using high-resolution RTK-GPS equipment across different estuarine typologies, including drowned river valleys, strong and weakly tidal estuaries, tidal lakes, and intermittently open/closed estuaries. These measurements were analysed against long-term (8–30+ years) tidal records to estimate inundation characteristics within the estuary. Study results indicate that the commonly used tidal plane method for predicting mangrove extent can incorrectly predict vertical extent by over 40 per cent. Likewise, hydroperiod is a poor predictor of extent as similar hydroperiods can be calculated across significantly different estuarine inundation patterns.Interestingly, the results indicate that mangrove elevations and inundation patterns are not uniform within or across estuaries, although there is uniformity across related estuarine typologies. For instance, inundation patterns in drowned river valley estuaries are more consistent (less extreme inundation and exposure events) than in estuaries with a variable tidal range, such as tidal lakes. Ultimately, this study highlights that predictions of mangrove extent should consider estuarine typology, the lifecycle of mangroves, and potential physio-adaptations to changing inundation patterns. Importantly, future tidal conditions may encourage biophysical adaptations in mangroves which may confound the extent of existing predictive techniques.

Under pressure: assessment of chemical stress on restored river sections using effect‐based methods

Aquatic ecosystems are affected by multiple stressors, including hydrological and morphological degradation, high nutrient loading, and chemical pollution. To improve freshwater habitats, hydromorphological restorations have been increasingly implemented. However, follow‐up assessments often show little to no improvement in ecological status, even years after restoration measures have been implemented. The success of restoration projects can be compromised by other stressors, such as insufficient water and sediment quality, which often receive less attention compared to nonchemical stressors. In this study, the impact of chemical stress on the outcome of five river restorations was evaluated ecologically, chemically, and ecotoxicologically. Overall, the habitat structure was considerably improved through the restoration measures, whereas the species communities did not show a consistent trend toward an improved ecological status. Effect‐based methods were used for an integrative assessment of the exposure to chemical mixtures in water and sediment samples of restored stream sections. Differences in toxicity between restored and non‐restored sections were found but did not show a consistent trend among the applied assays. In contrast, the chemical analysis showed that the sections of the same stream were similar in their chemical composition, and differences within a stream were primarily due to sediment contamination. The results of this study suggest that chemical pollution is a relevant factor preventing the success of restoration measures and, ultimately, the improvement of the ecological status of rivers. They also demonstrate the applicability of EBMs in water quality monitoring to detect mixture toxicity in streams and link chemical and ecological assessment.

Reintroduction of self-facilitating feedbacks could advance subtidal eelgrass (Zostera marina) restoration in the Dutch Wadden Sea

Extensive subtidal eelgrass (Zostera marina) meadows (~150 km2) once grew in the Dutch Wadden Sea, supporting diverse species communities, but disappeared in the 1930s and have been absent ever since. Identifying the most critical bottlenecks for eelgrass survival is a crucial first step for reintroduction through active restoration measures. Seagrasses are ecosystem engineers, inducing self-facilitating feedbacks that ameliorate stressful conditions. Consequently, once seagrass, including its self-facilitating feedbacks, is lost, reintroduction can be challenging. Therefore, we aimed to test whether 1) sediment stabilization and 2) hydrodynamic stress relief would facilitate eelgrass survival in a field experiment replicated at two sites in the Dutch Wadden Sea. We induced feedbacks using biodegradable root-mimicking structures (BESE-elements) and sandbag barriers. Root mimics had a significant positive effect, increasing the chances of short-term survival by +67% compared to controls. Contrary to our expectations, barriers decreased short-term survival probabilities by -26%, likely due to hydrodynamic turbulence created by the barrier edges, leading to high erosion rates (-14 cm). Site selection proved crucial as short-term survival was entirely negated on one of the two study sites after five weeks due to high floating and epiphytic macroalgae loads. No long-term survival occurred, as plants died at the other site two weeks later. Overall, we found that sediment stabilization by root-mimicking structures was promising, whereas manipulating hydrodynamic forces using sandbag barriers had adverse effects. A mechanistic understanding of transplant failures is required before attempting large-scale restoration. Our study indicates that for seagrass restoration in the Wadden Sea, one should carefully consider 1) the reintroduction of positive feedbacks through restoration tools, 2) donor population choice and transplantation timing, and 3) site selection based on local biotic and abiotic conditions. Optimizing these restoration facets might lower additive stress to a degree that allows long-term survival.