Defining Recovery Potential in River Restoration: A Biological Data-Driven Approach

Scientists and practitioners working on river restoration have made progress on understanding the recovery potential of rivers from geomorphological and engineering perspectives. We now need to build on this work to gain a better understanding of the biological processes involved in river restoration. Environmental policy agendas are focusing on nature recovery, reigniting debates about the use of “natural” reference conditions as benchmarks for ecosystem restoration. We argue that the search for natural or semi-natural analogues to guide restoration planning is inappropriate due to the absence of contemporary reference conditions. With a catchment-scale case study on the invertebrate communities of the Warwickshire Avon, a fifth-order river system in England, we demonstrate an alternative to the reference condition approach. Under our model, recovery potential is quantified based on the gap between observed biodiversity at a site and the biodiversity predicted to occur in that location under alternative management scenarios. We predict that commonly applied restoration measures such as reduced nutrient inputs and the removal of channel resectioning could be detrimental to invertebrate diversity, if applied indiscriminately and without other complementary measures. Instead, our results suggest considerable potential for increases in biodiversity when restoration measures are combined in a way that maximises biodiversity within each water body.

Vegetated Buffer Zone Restoration Planning in Small Urban Watersheds

Vegetated buffer zones (VBZ) are accepted worldwide as a low impact method to avoid non-point source pollution and restore the balance of river ecosystems. Strongly influenced by industrialization and urbanization, urban river ecology is seriously damaged, and restoration is tricky. This study established a complete buffer zone construction framework suitable for the small urban watershed, and its feasibility is verified in a small watershed in Northern China. First, common plants in the study area were selected to test their ability to purify pollutants, and plant combinations were optimized. Secondly, according to the field investigation, the reference buffer zone was determined, and its sewage interception capacity was tested through a runoff simulation experiment. Then, based on GIS and Phillips time and hydraulic models, the normal buffer width of the study area was obtained; 60 m for mainstream and 40 m for tributaries. By optimizing the vegetation scheme and delimiting an efficient buffer zone, the land occupation can be reduced by 17%. Finally, combined with the characteristics of different river sections, an elaborate VBZ restoration scheme is designed from the aspects of vegetation, planning, and zoning. Generally, this research will provide government and land managers scientific and practical ideas and technologies to formulate a land management policy for urban river buffer zones in order to find a balance between aquatic ecological protection and urban land use planning and optimize the allocation of construction funds.

Developing conceptual models for assessing benefits and impacts of USACE activities on freshwater mussel communities

In this report, we describe how aspects of existing freshwater mussel indices of biological integrity can be modified to fit within the planning paradigm established for developing and certifying ecological models for U.S. Army Corps of Engineers’ planning purposes. Herein, we present examples of using freshwater mussels for biological monitoring, how to calculate their associated IBIs specific to their region of origin and their potential use in ecosystem restoration planning. Additionally, we present general conceptual models that may be used in ecological model development and environmental benefits analysis for projects that focus on freshwater mussel habitat restoration.

Sustainability of Village Tank Cascade Systems of Sri Lanka: Exploring Cascade Anatomy and Socio-Ecological Nexus for Ecological Restoration Planning

Village Tank Cascade Systems (VTCSs) in the Dry Zone of Sri Lanka have evolved as sustainable ecosystems through human interventions to ensure water availability and other services for people and their environs during the last few millennia. However, VTCSs are vulnerable to global environmental changes resulting in continual deterioration of ecological health and hydro-socio-ecological status, crucial for the food and livelihood security of rural farming communities in the dry zone. This paper seeks to explore resource systems of the Mahakanumulla VTCS located in Anuradhapura district of Sri Lanka to (i) identify the spatial metrics linked to the sustainability and socio-ecological resilience of the VTCS, and (ii) determine interactions among system elements and their impacts on productivity and restoration challenges. The spatial analysis was conducted using a Digital Elevation Model (DEM), recent digital topographic map layers and Google Earth images to understand the spatial distribution and ensemble of tank environs. Participatory field assessment data were also used to determine socio-ecological nexus and factors that contribute to the reduction of ecological productivity of VTCS. The study revealed that the ensemble of tank environs is significant for providing regulatory and supporting ecosystem services (ES) and synergistic relationships with provisional ES of the VTCS. Results also revealed that the complex land-water-biodiversity-climate and food nexus that determines the productivity of the VTCS could be adopted in VTCS ecological restoration planning. The study presents a comprehensive framework to analyse causal factors and processes leading to reduction of overall productivity linked with variables of socio-ecological properties, vulnerability and resilience of the VTCS landscape.

Wetland Restoration Planning Approach Based on Interval Fuzzy Linear Programming under Uncertainty

When planning wetland restoration projects, the planting area allocation and the costs of the restoration measures are two major issues faced by decision makers. In this study, a framework based on the interval fuzzy linear programming (IFLP) method is introduced for the first time to plan wetland restoration projects. The proposed framework can not only effectively deal with interval and fuzzy uncertainties that exist in the planning process of wetland restorations but also handle trade-offs between ecological environment benefits and economic cost. This framework was applied to a real-world wetland restoration planning problem in the northeast of China to verify its validity and examine the credibility of the constraints. The optimized results obtained from the framework that we have developed indicate that higher ecological and social benefits can be obtained with optimal restoration costs after using the wetland restoration decision-making framework. The optimal restoration measure allocation schemes obtained by IFLP under different credibility levels can help decision makers generate a range of alternatives, which can also provide decision suggestions to local managers to generate a satisfactory decision-making plan. Furthermore, a comparison was made between the IFLP model and ILP model in this study. The comparison results indicate that the IFLP model provides more information regarding ecological environment and economic trade-offs between the system objective, certainty, and reliability. This framework provides managers with an effective way to plan wetland restoration projects, while transference of the model may help solve similar problems.

A small step or a giant leap: Accounting for settlement delay and dispersal in restoration planning

Understanding larval duration and hence dispersal potential of the European oyster Ostrea edulis is crucial to inform restoration strategies. Laval duration has an obligatory period of maturity to pediveliger (when larvae are ready to settle), but also an unknown period until metamorphosis is triggered by a settlement cue. The extent to which larvae can prolong the pediveliger period and delay metamorphosis has not been studied. Here we show that O. edulis larvae can delay metamorphosis for a period of 11 days, while retaining the capability to settle in high proportions when presented with a suitable settlement cue. O. edulis larvae are likely to be able to delay metamorphosis even further, since 80% of larvae in the control treatment were still alive when the experiment was terminated at day 14. The results indicate the ability of O. edulis larvae to more than double pelagic duration and probably further delay metamorphosis. We discuss these findings in the context of larval mortality, and the importance of O. edulis’ larval settlement requirements for dispersal potential, recruitment success and connectivity of restoration sites.

Quantifying the Variability of Forest Ecosystem Vulnerability in the Largest Water Tower Region Globally

Forests are critical ecosystems for environmental regulation and ecological security maintenance, especially at high altitudes that exhibit sensitivity to climate change and human activities. The Qinghai-Tibet Plateau—the world’s largest water tower region—has been breeding many large rivers in Asia where forests play important roles in water regulation and water quality improvement. However, the vulnerability of these forest ecosystems at the regional scale is still largely unknown. Therefore, the aim of this research is to quantitatively assess the temporal–spatial variability of forest vulnerability on the Qinghai-Tibet Plateau to illustrate the capacity of forests to withstand disturbances. Geographic information system (GIS) and the spatial principal component analysis (SPCA) were used to develop a forest vulnerable index (FVI) to assess the vulnerability of forest ecosystems. This research incorporates 15 factors covering the natural context, environmental disturbances, and socioeconomic impact. Results indicate that the measure of vulnerability was unevenly distributed spatially across the study area, and the whole trend has intensified since 2000. The three factors that contribute the most to the vulnerability of natural contexts, environmental disturbances, and human impacts are slope aspect, landslides, and the distance to the farmland, respectively. The vulnerability is higher in forest areas with lower altitudes, steeper slopes, and southerly directions. These evaluation results can be helpful for forest management in high altitude water tower regions in the forms of forest conservation or restoration planning and implementation towards sustainable development goals.