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Abstract Uptake and regeneration fluxes and concentrations of nutrients, i.e., nitrate (NO3−), ammonium (NH4+), phosphate (PO43−) and dissolved organic carbon (DOC), were evaluated upstream and downstream of a wastewater treatment plant (WWTP) in the River Wandle, UK, from July to October 2019. Using chamber techniques, water-specific nutrient concentrations were measured at two exposures (3 and 10 min) to calculate fluxes. The WWTP effluent contributed to elevated concentrations and modified flux rates, resulting in significant differences at the study sites. Compared with summer, the concentrations of NO3− and DOC increased while NH4+ and PO43− decreased in autumn. Nutrient fluxes varied both temporally and spatially in uptake (i.e., storage in sediments) or regeneration (i.e., release into river water). Under the actions of physical and biological processes, the fluxes of NO3− and NH4+ showed opposite flux directions. Dissolved oxygen (DO) and bioabsorption mainly affected PO43− and DOC fluxes, respectively. Specifically, across all sites, NO3− was −0.01 to +0.02 mg/(m2 s), NH4+ was −29 to +2 μg/(m2 s), PO43− was −2.0 to +0.5 μg/(m2 s), and DOC was −0.01 to +0.05 mg/(m2 s). Further, we did find that these variations were related to nutrient concentrations in the overlying water. Our results provide further evidence to show that reductions in river nutrients are paramount for improving river ecological conditions. Additionally, we suggest that more research is needed to evaluate chamber-based experimental approaches to make them more comparable to in-situ flux methods. Highlights • Sewage effluent resulted in elevated nutrient concentrations and modified fluxes. • Flux was affected by initial nutrient concentrations, DO and microbial activity. • Inexpensive approaches to study nutrient dynamics are needed for river restoration.

As the United Nations develops a post-2020 global biodiversity framework for the Convention on Biological Diversity, attention is focusing on how new goals and targets for ecosystem conservation might serve its vision of ‘living in harmony with nature’1,2. Advancing dual imperatives to conserve biodiversity and sustain ecosystem services requires reliable and resilient generalizations and predictions about ecosystem responses to environmental change and management3. Ecosystems vary in their biota4, service provision5 and relative exposure to risks6, yet there is no globally consistent classification of ecosystems that reflects functional responses to change and management. This hampers progress on developing conservation targets and sustainability goals. Here we present the International Union for Conservation of Nature (IUCN) Global Ecosystem Typology, a conceptually robust, scalable, spatially explicit approach for generalizations and predictions about functions, biota, risks and management remedies across the entire biosphere. The outcome of a major cross-disciplinary collaboration, this novel framework places all of Earth’s ecosystems into a unifying theoretical context to guide the transformation of ecosystem policy and management from global to local scales. This new information infrastructure will support knowledge transfer for ecosystem-specific management and restoration, globally standardized ecosystem risk assessments, natural capital accounting and progress on the post-2020 global biodiversity framework.

Raptors can be important components of urban ecosystems due to their role as apex predators, the presence of which may bring benefits to people. Urban environments may provide good quality habitats, and the raptors’ ability to utilize resources found here can contribute to their success. However, urban environments are socio-ecological systems and such mechanisms shaping habitats and ecological resources therein are less understood. This paper explores how raptors utilize urban resources, and the socio-ecological processes influencing their quality and availability. It begins with a systematic mapping of the literature to summarize the utility of urban resources by raptors with European distributions. Eighteen species were documented in the literature successfully exploiting novel hunting and/or nesting opportunities in both green and built-up locations of urban areas. We discuss how these may be consequential of human activities, some of which intentionally provided as subsidies, and how their utility by raptors create opportunities for human-raptor interactions further shaping public perception and decisions which potentially affect the raptors. Finally, we demonstrate these concepts by drawing on our experience from an urban peregrine falcon (Falco peregrinus) conservation site in London, UK. The paper concludes with a call for urban raptor conservation and research to consider social and ecological aspects together, appropriately reflecting urban environments as socio-ecological systems.

River ecosystem metabolism (REM) is a measure of ecological function which integrates gross primary production (GPP) and ecosystem respiration (ER). Urban rivers often receive effluents from wastewater treatment plants (WWTP) which frequently alter nutrient concentrations and modify temperature regimes of receiving water bodies. In this study, we applied the nighttime slope method (NSM) to estimate diurnal REM at sites above and below a wastewater outfall on the River Wandle, a tributary to the River Thames, and structural equation modelling (SEM) revealed that nutrient supply, water temperature and light availability were the main factors driving REM. Overall estimated GPP and ER from our study sites were like those of urban impacted rivers in other countries. Upstream to downstream, GPP values (0 ~ 21.2 mgO2·L− 1·d− 1) were similar, but ER values (5.5 ~ 10.1 mgO2·L− 1·d− 1) were significantly higher at the downstream site receiving WWTP effluents. GPP/ER ratios were > 1 indicating heterotrophic conditions during the study. We found that sites had similar activation energy associated with ER suggesting our work provides a useful reference for estimating temperature corrected metabolic processes for other urban rivers in the region. Structural equation modelling (SEM) revealed that nutrient supply, water temperature and light availability were the main factors driving REM. This research highlights the major environmental factors affecting REM providing needed evidence to inform river restoration and future in-stream management.

This study quantified CO2 emissions from tropical peat swamp soils in Brunei Darussalam. At each site, soil was collected from areas of intact and degraded peat and CO2 flux, and total organic content were measured ex situ. Soil organic content (~20–99%) was not significantly different between intact and degraded forest samples. CO2 flux was higher for intact forest samples than degraded forest samples (~1.0 vs. ~0.6 μmol CO2 m−2 s−1, respectively) but did not differ among forest locations. From our laboratory experiments, we estimated a potential emissions of ~10–20 t CO2 ha−1 y−1 which is in the lower range of values reported for other tropical peat swamps. However, our results are likely affected by unmeasured variation in root respiration and the lability of resident carbon. Overall, these findings provide experimental evidence to support that clearance of tropical peat swamp forests can increase CO2 emissions due to faster rates of decomposition.

Freshwater crayfish can be successful invaders that threaten native biota and aquatic ecosystems in numerous countries worldwide. Nonetheless, the inability of conventional crayfish survey techniques like trapping and handsearching to yield quantitative population data has limited the understanding of crayfish invasion biology and associated ecological impacts. Here, we employed a novel ‘triple drawdown’ (TDD) method to sample invasive populations of signal crayfish Pacifastacus leniusculus in a headwater stream in Northern England. The method was compared with conventional techniques of trapping and handsearching. The TDD method proved to be an effective technique with high capture efficiency, reporting signal crayfish densities from 20.5 to 110.4 animals/m 2 at our study sites. These numbers exceed any previous estimates for similar streams. The TDD showed the vast majority of individuals across all sites were juvenile or sub-adult (

1. The Eurasian otter (Lutra lutra), Smooth-coated otter (Lutrogale perspicillata) and Asian small-clawed otter (Aonyx cinereus) have all been previously reported from the Indian state of Uttarakhand. However, little information is available about these species’ current distribution in a mountainous region that is subject to increasing human-induced stressors (e.g. hydropower plants, pollution, sand and boulder mining, destructive fishing techniques, poaching). 2. Due to the important role of these otters in structuring riverine food webs (particularly taking account of their roles as top carnivores), it is critical that these animals receive suitable protection in the face of a projected rise in temperature, change in precipitation patterns, and associated river flows in this Himalayan biodiversity hotspot. This study assesses otter distribution in four rivers of Uttarakhand, as a basis for informing future conservation actions. 3. Field surveys were conducted (October 2018 – January 2019) in four Himalayan rivers (reaches of the Kosi, Ramganga, Khoh and Song Rivers), supported by semi-structured interviews (N=379) conducted with members of local communities to ascertain qualitative data on views and perceptions of otter species. In addition, community-based otter awareness camps were organized for local youths (N=105), adults (N=115) and school children (N=256 covering 10 schools). Habitat suitability maps were created using remote sensing data, survey findings and a Geographic Information System (GIS) to provide information about priority river reaches to be targeted for future conservation efforts. 4. This study provides critical interdisciplinary baseline information to guide decision-makers towards developing a targeted, otter-specific conservation program for this important Himalayan biodiversity hotspot. The otter conservation education programs conducted during this study resulted in a proposal to set up a community-based conservation initiative (CBCI) to monitor and report otter sightings from the area, potentially representing a way forward for achieving simultaneous otter conservation and associated ecosystem benefits for local communities.

We present an approach that uses satellite products to derive models for predicting lake chlorophyll from environmental variables, and for investigating impacts of changing environmental flows. Lake Turkana, Kenya, is the world's largest desert lake, and environmental flows from the Omo River have been modified since 2015 by the Gibe III dam in Ethiopia. Using satellite remote sensing, we have evaluated the influence of these altered hydrological patterns on large-scale lake phytoplankton concentrations for the first time. Prior to dam completion, strong seasonal cycles and large spatial gradients in chlorophyll have been observed, related to natural fluctuations in the Omo River's seasonal discharge. During this period, mean lake chlorophyll showed a strong relationship with both river inflows and lake levels. Empirical models were derived which considered multiple hydro-climatic drivers, but the best model for predicting chlorophyll-a was a simple model based on Omo River discharge. Application of this model to data for 2015–2016 estimated that during the filling of Gibe III annual mean Lake Turkana chlorophyll declined by 30%. Future water management scenarios based on Gibe III operations predict reduced seasonal chlorophyll-a variability, while irrigation scenarios showed marked declines in chlorophyll-a depending on the level of abstraction. These changes demonstrate how infrastructure developments such as dams can significantly alter lake primary production. Our remote sensing approach is easy to adapt to other lakes to understand how their phytoplankton dynamics may be affected by water management scenarios.

Electrofishing is a well‐established and widely used method for surveying fish populations. Nonetheless, its effectiveness is impacted by numerous factors, including water chemistry, habitat type and fish species. Both physiological and behavioural responses make bottom‐dwelling ‘benthic’ fish which lack swim bladders (e.g. European bullhead Cottus gobio) particularly difficult to survey by electrofishing. We compare the performance and practicalities of electrofishing for benthic fish at a rocky northern English headwater stream with two sampling methods originally designed for crayfish surveys; the triple drawdown method which involves repeated dewatering of a site, and the Pritchard Trap method which involves sunken traps filled with natural substrate that samples a small, fixed (0.25 m2) area of river bed. Both the Pritchard trapping and triple drawdown methods provided similar high‐density population density estimates for bullhead which were at least 2.5–5 times higher than predicted from electrofishing derived sweep depletion curves. Electrofishing and the triple drawdown method are both resource‐intensive, requiring expensive equipment and a team of trained operatives. These approaches also pose a risk to fish and non‐target organisms. In contrast, Pritchard Traps provide a cost‐effective passive, low risk survey method requiring minimal training and only one operative. Pritchard traps, therefore, show particular promise for benthic fish surveying and monitoring.

Freshwater ecosystems have a long history of non-native species invasions and are particularly susceptible to their impacts. This is in part because of intensive human use and ecological degradation of such ecosystems but also because the landscape characteristics of rivers and lakes – particularly hydrological connectivity – can facilitate invasions. These factors can also hinder attempts to control non-native and invasive species once they have been introduced. This chapter provides a background to freshwater ecosystem invasions before examining how landscape position and connectivity relate to species invasions. It then gives an overview of impacts resulting from freshwater ecosystem invasions and summarises some of the key forms of non-native control utilised in rivers and lakes. The chapter concludes by highlighting key areas of future research and investigation in relation to species invasions in freshwater ecosystems.

The Comal River, a spring-fed system in central Texas, was invaded in the 1960s by two Asian aquatic snails (Thiaridae: red-rimmed melania Melanoides tuberculata and quilted melania Tarebia granifera) and subsequently by three of their trematode parasites (the avian eye-fluke Philophthalmus gralli in the 1960s; the gill trematode Centrocestus formosanus in the 1990s; and the intestinal fluke Haplorchis pumilio in the 2000s). Previous snail collections (2001-2002) established that habitat conditions significantly affect the distribution of both snail species. However, the effects of snail size (known to influence infection prevalence) and habitat conditions (known to influence snail size) on trematode infection patterns in this system were not evaluated. In a re-evaluation of this data set, logistic regression analyses with individual snails showed that for both M. tuberculata and T. granifera populations, large snails were more likely to be infected than small snails, and habitat conditions were significantly related to infection in T. granifera. However, only snail size was significant in explaining the probability of infection in M. tuberculata. This result was confirmed by linear regression models, which showed that both infected and noninfected M. tuberculata used similar habitats, as large individuals in both infection categories were found in patches dominated by fine substrates and high levels of aquatic vegetation and detritus. For the large size-class of T. granifera, noninfected individuals were found primarily in habitats with silt/sand substrates and high vegetation and detritus cover, while infected individuals occurred among all available habitats. Using these results, we suggest that targeted sampling of large individuals of M. tuberculata in habitats with high detritus and vegetation and large individuals of T. granifera in any habitat can be used to efficiently ascertain parasite "hot spots" and to evaluate changes in parasite prevalence or detect the invasion of new parasites in these thiarid snails.

Understanding habitat selection by individual animals within their home range is crucial to facilitating their conservation. Peregrine falcon (Falco peregrinus) populations are increasingly urbanised, but little is known about their urban habitat use. In this study, we analysed the breeding habitat selection of peregrine falcons in London, United Kingdom, based on nest site locations identified through records of public sightings submitted to an online database between 2003 and 2018. We found peregrines displayed a preference for nesting in proximity to waterbodies, built-up areas and public parks and gardens, while wooded, agricultural and allotments areas were least preferred. We hypothesise that peregrines seek contrasting topography that proves advantageous for hunting in the vicinity of their nests, resulting in their selection of breeding sites within tall buildings that are adjacent to suitable foraging areas. From these findings, we conclude that (i) social drivers such as demand for green spaces and waterbodies near buildings shape peregrine nesting opportunities in the city and (ii) for urban planning to support conservation, we need further understanding of how each type of greenspace may be used differentially by raptors.

The spatial extent of seagrass is poorly mapped, and knowledge of historical loss is limited. Here, we collated empirical and qualitative data using systematic review methods to provide unique analysis on seagrass occurrence and loss in the United Kingdom. We document 8,493 ha of recently mapped seagrass in the United Kingdom since 1998. This equates to an estimated 0.9 Mt of carbon, which, in the current carbon market represents about £22 million. Using simple models to estimate seagrass declines triangulated against habitat suitability models, we provide evidence of catastrophic seagrass loss; at least 44% of United Kingdom’s seagrasses have been lost since 1936, 39% since the 1980’s. However, losses over longer time spans may be as high as 92%. Based on these estimates, historical seagrass meadows could have stored 11.5 Mt of carbon and supported approximately 400 million fish. Our results demonstrate the vast scale of losses and highlight the opportunities to restore seagrass to support a range of ecosystems services.

Multiple catchment controls contribute to the geomorphic functioning of river systems at the reach-level, yet only a limited number are usually considered by river scientists and managers. This study uses multiple morphometric, geological, climatic and anthropogenic catchment characteristics to produce a single national typology of catchment controls in England and Wales. Self-organising maps, a machine learning technique, are used to reduce the complexity of the GIS-derived characteristics to classify 4485 Water Framework Directive waterbodies into seven types. The waterbody typology is mapped across England and Wales, primarily reflecting an upland to lowland gradient in catchment controls and secondarily reflecting the heterogeneity of the catchment landscape. The seven waterbody types are evaluated using reach-level physical habitat indices (including measures of sediment size, flow, channel modification and diversity) extracted from River Habitat Survey data. Significant differences are found between each of the waterbody types for most habitat indices suggesting that the GIS-derived typology has functional application for reach-level habitats. This waterbody typology derived from catchment controls is a valuable tool for understanding catchment influences on physical habitats. It should prove useful for rapid assessment of catchment controls for river management, especially where regulatory compliance is based on reach-level monitoring.

Repeat observations underpin our understanding of environmental processes, but financial constraints often limit scientists’ ability to deploy dense networks of conventional commercial instrumentation. Rapid growth in the Internet-Of-Things (IoT) and the maker movement is paving the way for low-cost electronic sensors to transform global environmental monitoring. Accessible and inexpensive sensor construction is also fostering exciting opportunities for citizen science and participatory research. Drawing on 6 years of developmental work with Arduino-based open-source hardware and software, extensive laboratory and field testing, and incorporation of such technology into active research programmes, we outline a series of successes, failures and lessons learned in designing and deploying environmental sensors. Six case studies are presented: a water table depth probe, air and water quality sensors, multi-parameter weather stations, a time-sequencing lake sediment trap, and a sonic anemometer for monitoring sand transport. Schematics, code and purchasing guidance to reproduce our sensors are described in the paper, with detailed build instructions hosted on our King’s College London Geography Environmental Sensors Github repository and the FreeStation project website. We show in each case study that manual design and construction can produce research-grade scientific instrumentation (mean bias error for calibrated sensors –0.04 to 23%) for a fraction of the conventional cost, provided rigorous, sensor-specific calibration and field testing is conducted. In sharing our collective experiences with build-it-yourself environmental monitoring, we intend for this paper to act as a catalyst for physical geographers and the wider environmental science community to begin incorporating low-cost sensor development into their research activities. The capacity to deploy denser sensor networks should ultimately lead to superior environmental monitoring at the local to global scales.

Geomorphological alterations, hydrological disconnectivity and water pollution are among the dominant pressures affecting ecological integrity in urban streams. River restoration approaches often involve utilising in-stream structures to encourage flow heterogeneity and promote habitat diversity. However, few studies examine the success of such projects. In this study, fish density, biomass and community structure at paired restored and unrestored reaches across five tributaries of the River Thames were examined. Fish density varied among rivers and reaches but was generally higher at restored sites. Restored sites also exhibited higher overall fish biomass, attributed mainly to the presence of brown trout (Salmo trutta L.) at the River Wandle. Despite higher density and biomass values at restored sites, the community structure analysis did not identify strong links between either river or restoration status using either species-specific density or biomass. Our results highlight that although reach-scale restoration can lead to localised increases in species density and biomass, this may chiefly be due to aggregation owing to preferential habitats created through restoration activities at these sites. Over larger spatial scales, significant improvements to species richness and diversity are likely to be limited due to the poor water quality and disconnected nature of these urban streams. Whilst reach-scale restoration clearly has the potential to provide preferential habitats for fish species, future efforts should focus on improving connectivity for fish across the wider Thames basin network by removing barriers to passage, improving water quality, restoring watershed processes and creating well-connected, diverse habitats which can facilitate the survival of a wide array of fish species throughout their life cycle.

Recent studies have highlighted cities as prime locations for the introduction, establishment, and spread of non-native and invasive species. As the hydrological arteries of cities, urban river corridors have an important role to play in influencing species invasions. This overview examines existing literature to consider (a) how the landscape functions of urban river corridors (habitat, conduit, barrier/filter, sink, and source) relate to species invasions; (b) the organismal and geographical foci of research into non-native species invasions along urban rivers; and (c) the need to more fully consider the roles that non-native species may play in the recombinant communities of novel urban river ecosystems. The review ends with an identification of research priorities at the intersection of urban river corridor function and invasion biology.

Greater than 80% of species on Earth are awaiting formal description, and simultaneously, many of these species unknown to science are becoming extinct. Here we highlight the importance and benefits of collaborating and working in interdisciplinary research groups, to improve quality and efficiency of both ecological and taxonomic research. The aim of this paper is to share and critique two methods used when conducting environmental field research in taxonomically data-poor parts of the world, such as Borneo. Through discussions with geographers, ecologists and taxonomists these two methods are evaluated. We conclude with a suggested solution to push taxonomic knowledge barriers by creating inter-disciplinary communities of researchers who work together to improve taxonomic identifications.

Waterfalls are geomorphic features that often partition streams into discrete zones. Our study examined aquatic communities, litter decomposition and periphyton growth rates for above- and below-waterfall pools in Ulu Temburong National Park, Brunei. We observed higher fish densities in below-waterfall pools (0.24 fish m−2 vs. 0.02 fish m−2 in above-waterfall pools) and higher shrimp abundance in above-waterfall pools (eight shrimp/pool vs. less than one shrimp/pool in below-waterfall pools). However, macroinvertebrate densities (excluding shrimp) were similar among both pool types. Ambient periphyton was higher in below-waterfall pools in 2013 (4.3 vs. 2.8 g m−2 in above-waterfall pools) and 2014 (4.8 vs. 3.4 g m−2 in above-waterfall pools), while periphyton growth rates varied from 0.05 to 0.26 g m−2 days−1 and were significantly higher in below-waterfall pools in 2014. Leaf litter decomposition rates (0.001 to 0.024 days−1) did not differ between pool types, suggesting that neither shrimp nor fish densities had consistent impacts on this ecosystem function. Regardless, this research demonstrates the varied effects of biotic and abiotic factors on community structure and ecosystem function. Our results have highlighted the importance of discontinuities, such as waterfalls, in tropical streams.

Non-native and invasive species of plants and animals represent a major threat to global biodiversity and associated ecosystem services. Developing an understanding of processes, impacts and contro...

Terrestrial protected areas and river reaches managed by local stakeholders can act as management tools for biodiversity conservation. These areas have the potential to safeguard fish species from stressors such as over-fishing, habitat degradation and fragmentation, and pollution. To test this idea, we conducted an evaluation of the potential for managed and unmanaged river reaches, to conserve threatened freshwater fish species. The evaluation involved sampling fish diversity at 62 sites in major rivers in Uttarakhand, India (Kosi, Ramganga and Khoh rivers) both within protected (i.e. sites within Corbett and Rajaji Tiger Reserves and within managed reaches), and unprotected areas (i.e. sites outside tiger reserves and outside managed reaches). In total, 35 fish species were collected from all sites, including two mahseer (Tor) species. Protected areas had larger individual fish when compared to individuals collected outside of protected areas. Among all sites, lower levels of habitat degradation were found inside protected areas. Non -protected sites showed higher impacts to water quality (mean threat score: 4.3/5.0), illegal fishing (4.3/5.0), diversion of water flows (4.5/5.0), clearing of riparian vegetation (3.8/5.0), and sand and boulder mining (4.0/5.0) than in protected sites. This study supports the importance of existing terrestrial protected areas and managed sites for conserving threatened fish and preventing harmful activities.

Mahseer are popularly regarded by anglers as the king of freshwater fishes, and are valued across the Himalayan and South-east Asian regions. In India, mahseer are important game fish. Mahseer populations and their habitats face a range of anthropogenic threats, however, including unregulated fishing and habitat fragmentation as a result of hydro-development projects. Catch-and-release angling for mahseer attracts both national and international anglers and could provide information about rivers while generating revenue for regional economies. In this context, we evaluated catch-and-release angling records from rivers that flow within two Indian reserves (the Ramganga and Jia Bharali Rivers in Corbett and Nameri Tiger Reserves, respectively). Golden mahseer Tor putitora in the Ramganga and golden and chocolate mahseer Neolissochilus hexagonolepis in the Jia Bharali were the most frequently caught fish species. Catch data suggested these game fish populations are probably not negatively affected by angling activities. Interviews with stakeholders highlighted support for catch-and-release angling, mainly because of its perceived economic benefits. The data obtained in this research could potentially assist with both fish conservation and the protection of associated aquatic ecosystems.

Waterfalls have unique physical characteristics and harbour highly specialised macroinvertebrate communities, but have been the subject of very few ecological studies. There are no previous studies of trophic structure of waterfall assemblages. It was hypothesised that because of the steep gradient of waterfalls and low retention of terrestrial-based resources, the abundant basal food resources would be periphyton. In addition, because of the frequent scouring flood events, it was predicted that periphyton would be a significant source of food for filter feeders. Waterfalls in the Ulu Temburong National Park (Brunei Darussalam) were used in the present case study. Methods included stable carbon (C)- and nitrogen (N)-isotope analyses (SIA; δ13C and δ15N of leaf litter and periphyton) and gut-content analysis (GCA) of the most the abundant macroinvertebrates. With δ15N values ranging from –1.9 to 5.5‰, literature suggests that this indicates that herbivores (Heptageniidae and Blephariceridae), omnivores (Simuliidae and Hydropsychidae) and predators (Buccinidae) live in the waterfalls. Apart from Buccinidae, the taxa had δ13C signatures ranging from –33 to –26‰, with a high dependence on periphyton, which is similar to other tropical-stream biotopes. The present study suggests that despite scouring velocities, waterfalls support animals with a range of diets, based on grazing or scraping, filter feeding and predation.

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Promoting a fish as a flagship species (i.e. a charismatic animal that promotes awareness) is a management tool to improve the effectiveness of conservation measures. However, to be successful this approach requires strong stakeholder support. To investigate the feasibility of the flagship species approach and degree of stakeholder support in India, semi-structured interviews were conducted with forest managers, anglers and village members in Uttarakhand. Stakeholders were supportive of the flagship approach and the golden mahseer was favoured because of economic benefits associated with recreational angling.

The term ‘synurbic’ is sometimes used within the more recent urban ecology literature to refer to a species that colonises or is found within urban ecosystems, but this is too simplistic an interpretation. We consider that the term should be reserved for species populations that have higher densities in urban compared to rural areas, as a quantifiable measure of preferential urban association. This paper clarifies the terms ‘synurbic’ and ‘synurbization’ and considers some of the problems of defining ‘urban’, before detailing some of the positive responses exhibited by urban species that may lead to synurbic populations. It may be particularly important to determine whether responses drive directional selection leading to adaptation and genetic differentiation, or are within the range of expected phenotypic plasticity, and observed responses are discussed within this context. Further investigation of species response to urban environments, including the frequency and significance of adaptation, will be important for understanding the emergence of synurbic populations and their implications for urban biodiversity and management. We hope that the terms defined here will form the basis for comparative studies of urban species.

The River Thames through central London has seen significant environmental recovery, particularly in regard to water quality, but a substantial barrier to further ecological improvement is the spatial restriction of riparian areas. Flood defence walls represent a potential habitat for ecological improvements to benefit biodiversity. However before restoration actions are considered, an understanding of the current biodiversity and ecological status of these structures is necessary. Physical habitat and macroinvertebrate richness of flood defence walls at 15, evenly spaced sites along a 32 Km reach in central London were evaluated. We found no longitudinal patterns in total macroinvertebrate richness among our 15 sites, but did find that richness was influenced by wall type. Specifically, we found the highest richness on brick walls and lowest richness on concrete walls. Further, wall sections with algal cover supported significantly higher numbers of macroinvertebrates than sections lacking algal cover. However, reaches of the river where the channel was constricted had fewer macroinvertebrates likely due to scouring flows. These results show that macroinvertebrates of the river walls are influenced by habitat availability (i.e., wall type) and localised river flows. This work suggests that appropriate management of river wall habitats has the potential to enhance the biodiversity of highly modified, urban rivers.

The effects of urbanization on hydrology, water quality and macroinvertebrates were examined in 7 headwater tributaries of the St. Johns River in the Atlantic Coastal Plain of northeast Florida. All streams had sandy substrata and drained small catchments (24–231 ha) that ranged from 0 to 51% total impervious area (TIA). Streams unaffected by urbanization had intermittent stream flow and completely dry channels for several weeks in autumn and spring. Urbanized streams always possessed channel water, but 2 streams ceased flowing and became stagnant in autumn and spring. Principle components analysis of chemical and physical measures (i.e. conductivity, nutrients, pH, metals, and stream flow) produced one axis (PCA1) that explained 54% of the total variation among the streams. The variables that loaded negatively on this axis were associated with low flows, while the variables that loaded positively were associated with urban land-use. PCA1 was also positively associated with %TIA. Macroinvertebrate richness ranged from 27 to 45 taxa and was positively associated with %TIA. Macroinvertebrate biomass ranged from 3 to 45 g AFDM/m2 and showed a significant, exponential relationship with PCA1 (r2 = 0.93) with greatest biomass occurring at intermediate %TIA. Invertebrate community structure in the urbanized streams appeared to be mainly influenced by hydrologic factors (perennial vs. intermittent flow regimes). The effects of urbanization on both hydrological and biological variables among the study streams were apparent, but also influenced by site-specific conditions.

We tested the hypothesis that American lobster (Homarus americanus) movement can be described as diffusion. In 2001 and 2002, 3689 lobsters, captured by experimental trap and trawl surveys, were tagged and released in Northum- berland Strait, Canada. Recaptures (n = 413) were reported by roughly 200 commercial fishermen, up to 3 years after re- lease. Only six lobsters, all females, were recaptured more than once. Recapture rates were marginally higher for males (male 12%, female 10%) and varied with area of release (range: 5%-12%) and the fishing gear used for tagging (trap 12%, trawl 11%). Maximum and mean displacements between release and recapture were 58.3 and 12.3 km, respectively. The positive linear correlation between mean square displacement (MSD) and time between release and recapture provides evidence for diffusion. We calculate a diffusion coefficient (D )o f 13 km 2 � week -1 ; there was no difference in D between sexes. A power analysis showed that MSD is underestimated at small sample sizes. There were insufficient data to test for differences in D associated with sexual maturity or shell hardness at time of release. During the summer in Northumber- land Strait, the lobster population spreads about 20 km. The demographic consequences of seasonal diffusion of lobster warrant study. Resume´ : Nous evaluons l'hypothese selon laquelle les deplacements du homard d'Amerique (Homarus americanus) peu- vent etre interpretes comme des diffusions. En 2001 et 2002, nous avons marqueet relache´ 3689 homards captures lors d'inventaires au casier experimental et au chalut dans le detroit de Northumberland. Les recaptures (n = 413) ont etesig- nalees par environ 200 pecheurs commerciaux, jusqu'a` 3 ans apres la liberation. Seuls six homards, tous femelles, ont ete´ captures plus d'une fois. Les taux de recapture etaient legerement plus eleves chez les males (males 12%, femelles 10%) et variaient en fonction du point de liberation (etendue: 5-12%) et l'engin de peche utiliselors du marquage (casier 12%, chalut 11%). Les distances maximale et minimale des deplacements entre la liberation et la recapture etaient respective- ment de 58,3 et 12,3 km. La correlation lineaire positive entre le deplacement moyen au carre´ (MSD) et le temps entre la liberation et la recapture est une indication de diffusion. Nous calculons que le coefficient de diffusion (D) est de 13 km 2 � semaine -1 , sans difference de D entre les sexes. Une analyse de puissance montre que MSD est sous-estimedans

Kate Baker, Michael A. Chadwick, and Zohrah Haji Sulaiman (2016) Linking ecology with river geomor- phology and hydrology (geomorphic and hydraulic template) plays an important role in the study of macroinver- tebrate biodiversity. This understanding and knowledge is crucial in implementing sensible conservation management for ecosystem health monitoring. However, most macroinvertebrate research has been conducted in temperate ecosystems. This study examines the eco-hydrogeomorphology and macroinvertebrate biodiversity of two remote tropical streams in northern Borneo (Bukit Pagon catchment, Brunei Darussalam’s highest mountain - 1850 m) using temperate classification models, more specifically, biotopes. Fast flowing biotopes were defined as bedrock runs and cobble riffles whilst the slow flowing biotopes were deposition pools. Macroinvertebrate size structure associated with biotopes, which can influence overall ecological processes, was also investigated. Forty-three macroinvertebrate taxa were recorded during the study; biodiversity was similar between the study streams. There were differences among biotopes with the lowest diversity occurring in fast flowing biotopes (p = 0.05*). Community structure also varied among the biotopes. Cluster analysis of macroinvertebrate abundance revealed an 0.8 dissimilarity between the fast and slow biotopes. Several taxa were found in multiple biotopes, which is likely linked to the occurrence of moss and leaf litter. Macroinvertebrate size structure distribution between the fast and slow biotopes was statistically different. Our findings suggest biotopes may be an appropriate scale to investigate macroinvertebrate biodiversity in tropical streams. Specifically, we found that biotopes had different macroinvertebrate communities and richness. Further research is required to understand the importance of habitat parameters that are not directly related to flow velocities such as moss. These habitats are important as places of refuge, allowing colonisation that would otherwise be inhospitable during flood periods.

Input, storage, export potential, and system-level processing of coarse organic matter were investigated in the intermittent streams that drain the Bear Brook Watershed in Maine (BBWM). BBWM is a paired catchment study investigating ecosystem effects of atmospheric N and S deposition. We predicted that the increased N loading to the treatment catchment would elevate input of organic matter, result in higher levels of coarse organic matter biomass, and increase litter processing rates in the treatment stream relative to the reference stream. We found that the streams draining BBWM did not have statistically different coarse organic matter input, biomass, or processing rates and we found only modest differences in export potential. System-level processing rates for maple (Acer spp.) litter were similar to rates previously quantified using litterbag methods. However, system-level processing rates for American beech (Fagus grandifolia) litter were an order of magnitude faster than rates measured with litterbags. This difference was likely due to movements of these leaves from riffle/runs and pools into debris dams, rather than differences in measurements of leaf tissue processing rates between methods. Organic matter dynamics of the intermittent streams at BBWM were similar to other forested, headwater streams. Our results indicate that the long-term N manipulation experiment at BBWM has not altered input, storage or processing of coarse organic matter in the treatment stream. Physical characteristics of these stream ecosystems appear to regulate organic matter dynamics rather than differences in nutrient chemistry.

We assessed the effect of atmospheric nitrogen (N) deposition on secondary production in a first-order intermittent stream at the Bear Brook Watershed in Maine (BBWM). BBWM is a paired-catchment experiment designed to determine the effects of N deposition on a forested ecosystem. Nitrogen as (NH4)2SO4 has been applied to the treatment catchment since 1989, with the adjacent catchment serving as a reference (both are drained by a firstorder intermittent stream). Secondary production and detritus biomass were quantified for 2 yr. Production did not vary between streams (range 5 1.7‐2.3 g ash-free dry mass m 22 yr 21 ) but was ;35% higher for both streams in the second year. The distribution of production among functional feeding groups varied little between streams but differed among taxa. Detritus biomass was similar between streams but was ;25% higher in the second year. The (NH4)2SO4 treatment had no effect on production in the treatment stream. The statistically identical level of production between streams is presumably because of similar habitat, channel drying, and trophic resources. Difference in production between years was positively related to detritus biomass. Differences in the distribution of production among taxa between streams were likely the result of contrasts in the duration of flowing water, with the treatment stream having the longer duration. Our study indicates that patterns of litter input and channel drying, rather than N deposition, control levels of secondary production in these intermittent streams by altering both resource availability and community structure. These variables apparently override the effects of N deposition in regions where nitrogen is not a limiting nutrient.

The Bear Brook Watershed in Maine (BBWM) is a paired catchment study investigating ecosystem effects of N and S deposition. Because of the decade long (NH4)2SO4 addition, the treatment catchment has higher stream NO3− and enriched foliar N concentrations compared to the reference catchment. We investigated how both stream N and foliar N affect stream detritus processing. Differences in litter processing were assessed by measuring mass loss, tissue softness, and shredder biomass. To examine both stream effects and leaf source, N-enriched and reference litter bags were prepared for 3 leaf species and placed in each stream. Red maple leaves were examined in 1997, 1998, and 1999. Sugar maple and American beech were examined in 1999. In all years, the only stream effects were increased mass loss for sugar maple and higher shredder biomass for red maple in 1998 in the treatment stream. Several leaf source effects were observed. N-enriched leaves of sugar maple, American beech, and red maple in 1998 had ...

Studies were conducted to assess the feasibility of a primary FIsh Gill Cell culture system (FIGCS) for both laboratory and field based environmental monitoring of rivers known to be affected by metal contamination. FIGCS were exposed in the laboratory and in the field to water from the River Hayle, a metal-contaminated system in Cornwall, United Kingdom. Water chemistry, including transition metal concentrations, changes in transepithelial electrical resistance (TEER), cell viability and the expression of metal responsive genes, metallothionein A and B were measured. FIGCS tolerated river water in the laboratory showing no loss in TEER or cell viability following 24 h exposure. The cells also tolerated transport to the field (∼1000 km and 30 h) and exposure to unfiltered and filtered river water. Metallothionein A and B, a measure of intracellular biologically active metals, expression was induced in the laboratory and field on exposure to water from sites with elevated metal concentrations compared to those sites where metal levels were below water metal Environmental Quality Standards. This demonstrates that FIGCS detects bioreactive metals in river waters on exposure in the laboratory or field and can be used for on-site environmental monitoring as well as investigations into bioavailability and toxicity of contaminant mixtures in natural waters.

Secondary production of the burrowing mayfly, Hexagenia limbata, was quantified from four sites differing in seasonal salinity within the Lower Mobile River, Alabama, from October 1995 to September 1996. This population was univoltine, with emergence occurring from late May through early August. Comparisons with other populations of this species showed latitudinal trends suggesting that summer temperatures may exceed an upper thermal threshold for growth. Longitudinal differences in riverine salinity (i.e., upriver sites, 0‰; downriver sites, 5.5‰ maximum salinity) explained most of the differences among sites, both for average density (upriver sites, 75.6 mayflies m 22

During the negotiation of internationaland European environmental regulations,the industry sector typically raises theissue of the cost of compliance. It isoften maintained that the cost ofcomplying with environmentalregulations restricts business profitabilityand competitiveness. This paperprovides an overview of the cost ofcompliance by considering thearguments, strategies and cost estimatesthat were presented by industry duringthe negotiations of several differentenvironmental regulations in Europe andNorth America, and at the global level.It examines the difficulties associatedwith comparing costs using pre- andpost-regulation cost data and discussesthe strategies adopted during thenegotiations of the regulation and oncethe regulation was implemented. Thepaper concludes that although someproposals for regulation may imposeburdens on industry, which it willoppose, industry has come to recognizethat environmental regulation does notnecessarily mean increased costs at thelevel anticipated. While regulationcannot guarantee innovation or lead togreater competitiveness and higherproductivity for all firms, those thatseize the opportunities will usually gainbenefits. The paper reinforces the viewthat the EU should give carefulconsideration to the costs presented byindustry as in the past it has tended tooverestimate costs of compliance andunderestimate the potential for thedevelopment of new technology. Theintroduction of independent costassessments and technology assessmentsmay be one way of overcoming thisproblem. Copyright © 2001 John Wiley