The challenge of valuing ecosystem services that have no material benefits

Since the Millennium Ecosystem Assessment, ecosystem service science has made much progress in framing core concepts and approaches, but there is still debate around the notion of cultural services, and a growing consensus that ecosystem use and ecosystem service use should be clearly differentiated. Part of the debate resides in the fact that the most significant sources of conflict around natural resource management arise from the multiple managements (uses) of ecosystems, rather than from the multiple uses of ecosystem services. If the ecosystem approach or the ecosystem service paradigm are to be implemented at national levels, there is an urgent need to disentangle what are often semantic issues, revise the notion of cultural services, and more broadly, practically define the less tangible ecosystem services on which we depend. This is a critical step to identifying suitable ways to manage trade-offs and promote adaptive management. Here we briefly review the problems associated with defining and quantifying cultural ecosystem services and suggest there could be merit in discarding this term for the simpler non-material ecosystem services. We also discuss the challenges in valuing the invaluable, and suggest that if we are to keep ecosystem service definition focused on the beneficiary, we need to further classify these challenging services, for example by differentiating services to individuals from services to communities. Also, we suggest that focussing on ecosystem service change rather than simply service delivery, and identifying common boundaries relevant for both people and ecosystems, would help meet some of these challenges

Insight into long-term ecological dynamics from the Lynn Brianne Observatory

Understanding the erosion of freshwater biodiversity has become a global imperative, but consistent series of long-term data from which to appraise changes are rare. In central Wales (UK), the Lynn Brianne Stream Observatory has provided unique insight into the complexity of biodiversity dynamics over four decades, revealing how apparent stasis in alpha- and beta-diversity might mask non-random functional changes in macroinvertebrate assemblages. Assessments of synchrony and stability at population and community levels reveal the effect of climatic variations in which warmer, wetter phases of the North Atlantic Oscillation (NAO) have been associated with large interannual changes in community composition. Moreover, these positive NAO periods have brought greater synchrony in species abundances within streams (community synchrony) and across streams (spatial population synchrony). Increasing synchrony can destabilise ecosystems with consequences for the persistence of populations. Preliminary analyses at Lynn Brianne suggest that species with greater spatial synchrony tend to decline in abundance over time. For instance, the abundance of cold-adapted species has declined by 40% since the 1980s reflecting the general increase in temperatures. Moreover, populations of these species displayed significantly higher spatial synchrony than warm-adapted species, which increased by 30% over the same time period. We suggest that both directional climate warming and the NAO contribute to the long-term reorganisation of benthic communities in temperate headwater

Testing the ecosystem service cascade framework for Atlantic salmon

Aligning nature protection with human well-being for the UN Sustainable Development Goals implies that conservation monitoring should indicate the sustainability of ecosystem services (ES). Here we test the value of the ES cascade framework using national, multi-decadal data for an iconic freshwater fish, the Atlantic salmon Salmo salar. For the first time, we assemble all long-term monitoring data for England and Wales along the ES cascade for this species from resource to benefit: juvenile density to measure the biological resource, returning adult numbers to measure potential ES use, and rod catches and angling effort as measures of actual ES use. We aimed to understand how the ES cascade framework reconciled conservation with ES sustainability targets. Only some linkages along the ES cascade could be evidenced: in catchments where juveniles declined, rod catches also generally decreased, but angling effort declined everywhere irrespective of the biological resource trends. We suggest that i) programmes focused on juvenile monitoring provide an early-warning system for ES provision as well as nature conservation, ii) the ES cascade framework can reconcile nature conservation and ES sustainability if monitoring efforts link biological resources fully to the ES, and ES monitoring explicitly relates biological resources to human use

Regional planning of river protection and restoration to promote ecosystem services and nature conservation

[Except] International conservation and sustainability agendas (CBD, 2010; European Union, 2011; IPBES, 2018; United Nations, 2018) have repeatedly called for conservation, restoration and sustainable use of biodiversity as well as the enhancement of ecosystem services and benefits to society. These calls are particularly relevant for freshwater ecosystems, which combine conservation interest and high societal value through the supply of multiple ecosystem services (Tharme, Tickner, Hughes, Conallin, & Zielinski, 2018). Freshwater habitats, biodiversity and ecological functions are also amongst the most threatened worldwide, due to a broad range of anthropogenic pressures (IPBES, 2018; Reid et al., 2019). In the European Union, 63% of river and lake habitats protected under the Habitats Directive are considered to hold “Unfavourable” conservation status, and 60% of water bodies are not in “Good” ecological status (IPBES, 2018). [...]Fundação para a Ciência e Tecnologia (FCT) through a doctoral fellowship (SFRH/BD/115030/2016) co-financed by the European Social Fund through the Human Capital Operational Program (POCH), the North Portugal Regional Operational Programme (NORTE2020) and national funds from the Ministério da Ciência, Tecnologia e Ensino Superior (MCTES). CV would like to acknowledge the support of the Portuguese Infrastructure of Scientific Collections (POCI-01-0145FEDER-022168) (PRISC.pt). JG developed this work within the scope of the project proMetheus – Research Unit on Materials, Energy and Environment for Sustainability, FCT Ref. UID/05975/2020, financed by national funds through the FCT/MCTE

Accounting for Dilution of SARS-CoV-2 in Wastewater Samples Using Physico-Chemical Markers

Most sewer networks collect domestic wastewater and a variable proportion of extraneous water, such as rainwater, through surface runoff and industrial discharges. Accounting for wastewater dilution is essential to properly quantify wastewater particle loads, whether these are molecular fragments of SARS-CoV-2, or other substances of interest such as illicit drugs or microplastics. This paper presents a novel method for obtaining real-time estimates of wastewater dilution and total daily volume through wastewater treatment works, namely when flow data is not available or unreliable. The approach considers the levels of several physico-chemical markers (ammonia, electrical conductivity, and orthophosphate) in the wastewater against their dry-weather levels. Using high-resolution data from the national Wastewater Surveillance Programme of Wales, we illustrate how the method is robust to spikes in markers and can recover peaks in wastewater flow measurements that may have been capped by hydraulic relief valves. We show the method proves effective in normalising SARS-CoV-2 viral loads in wastewater samples and discuss other applications for this method, looking at wastewater surveillance as a vital tool to monitor both human and environmental health

Systematic variation in food web body-size structure linked to external subsidies.

The relationship between body mass (M) and size class abundance (N) depicts patterns of community structure and energy flow through food webs. While the general assumption is that M and N scale linearly (on log-log axes), nonlinearity is regularly observed in natural systems, and is theorized to be driven by nonlinear scaling of trophic level (TL) with M resulting in the rapid transfer of energy to consumers in certain size classes. We tested this hypothesis with data from 31 stream food webs. We predicted that allochthonous subsidies higher in the web results in nonlinear M-TL relationships and systematic abundance peaks in macroinvertebrate and fish size classes (latter containing salmonids), that exploit terrestrial plant material and terrestrial invertebrates, respectively. Indeed, both M-N and M-TL significantly deviated from linear relationships and the observed curvature in M-TL scaling was inversely related to that observed in M-N relationships. Systemic peaks in M-N, and troughs in M-TL occurred in size classes dominated by generalist invertebrates, and brown trout. Our study reveals how allochthonous resources entering high in the web systematically shape community size structure and demonstrates the relevance of a generalized metabolic scaling model for understanding patterns of energy transfer in energetically 'open' food webs

Populations of high-value predators reflect the traits of their prey

The extent to which prey traits combine to influence the abundance of predators is still poorly understood, particularly for mixed predators in sympatry and in aquatic ecosystems. In this study, we characterise prey use and distribution in iconic bird (grey wagtails and Eurasian dippers) and fish species (brown trout and Atlantic salmon) to assess whether prey traits could predict populations of these four riverine predators. Specifically, we hypothesised that: 1) prey key traits would predict predator populations more effectively than 2) diversity of prey traits, 3) the taxonomic abundance or richness of prey (known as traditional or mass-effect types of biodiversity) or 4) the prevailing environmental conditions. Combined predator population sizes were predicted better by a few key traits – specifically those revealing prey habitat use, size and drifting behaviour – than by prey diversity or prey trait diversity or environmental conditions. Our findings demonstrate that the complex relationships between prey assemblages and multiple predator species can be represented mechanistically when the key prey traits that govern encounter and consumption rates are identified. Given their apparent potential to reveal trophic relationships, and to complement more traditional measures of prey abundance, we advocate further development of trait-based approaches in predator–prey research

Negative effects of parasite exposure and variable thermal stress on brown trout (Salmo trutta) under future climatic and hydropower production scenarios

Future water temperature changes may have a profound impact on fish-parasite interactions. However, while the effect of temperature on fish, and particularly salmonids, is well-understood, its combined effects with parasitic exposure are not. Here, we use a multi-stage experimental approach to explore the impact of increased water temperatures consistent with persistent climate change-induced warming and extreme thermal fluctuations from hydropower (thermopeaking) on brown trout alevins and fry before and during exposure to Saprolegnia parasitica. Parasite exposure had the strongest and most significant effect on survival of both host life stages. The combination of parasite exposure, thermal pre-conditioning and the ongoing thermal regime had a weak but significant influence on alevin mortality. Both parasite-exposed alevin and fry experienced increased mortality when a constant increase in temperature was combined with intermittent thermal increases. The outcomes of this experimental approach provide the basis for future studies scaling up the potential impacts of temperatures and parasite exposure that key fish species may face in the wild. They also highlight the effects of anthropogenic changes on brown trout populations, as pressures on aquatic organisms are likely to intensify in future climate scenarios with increased hydropower development and thermopeaking, particularly in the presence of pathogens