John Iwan Jones

John Iwan Jones
Queen Mary, University of London | QMUL · School of Biological and Chemical Sciences

About

135
Publications
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8,261
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Publications

Publications (135)
Article
Full-text available
Headwater streams are natural sources of methane but are suffering severe anthropogenic disturbance, particularly land use change and climate warming. The widespread intensification of agriculture since the 1940s has increased the export of fine sediments from land to streams, but systematic assessment of their effects on stream methane is lacking....
Article
Aquatic habitats are severely threatened by human activities. For anadromous species, managing freshwater habitats to maximise production of more, larger juveniles could improve resilience to threats in marine habitats and enhance population viability. In some juvenile salmonid habitats, complexity created by large substrates provides resources and...
Article
Microplastics are ubiquitous in both marine and freshwater ecosystems, where they can act as a physical contaminant, as well as interact with chemicals present in the environment. It has been suggested that chemical contaminants can sorb to microplastics, such that microplastics act as a vector for chemicals into aquatic biota and enhance their neg...
Article
Subterranean streams represent unique heterotrophic ecosystems, usually supported by organic matter imported from the surface. Traditionally, the biological communities from subterranean streams were characterized as simple associations, with low diversity and species abundance, comprising mostly aquatic invertebrates connected by few trophic links...
Article
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While many studies have considered the ability of eDNA to assess animal communities in lacustrine settings, fewer have considered riverine systems, particularly those spanning the environmental gradients present in large river basins. Such dynamic systems are challenging for eDNA biomonitoring due to differing eDNA transport distances in rivers and...
Article
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Coexistence of ecomorphologically similar species in diverse Neotropical ecosystems has been a focus of long-term debate among ecologists and evolutionary biologists. Such coexistence can be promoted by trophic plasticity and seasonal changes in omnivorous feeding. We combined stomach content and stable isotope analyses to determine how seasonal va...
Article
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Coexistence of ecomorphologically similar species in diverse Neotropical ecosystems has been a focus of long-term debate among ecologists and evolutionary biologists. Such coexistence can be promoted by trophic plasticity and seasonal changes in omnivorous feeding. We combined stomach content and stable isotope analyses to determine how seasonal va...
Article
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)...
Article
Historical mining activities cause widespread, long-term trace metal contamination of freshwater ecosystems. However, measuring trace metal bioavailability has proven difficult, because it depends on many factors, not least concentrations in water, sediment and habitat. Simple tools are needed to assess bioavailabilities. The use of biomonitors has...
Article
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Despite growing interest in the environmental impact of microplastics, a standardized characterization method is not available. We carried out a systematic analysis of reliable global data detailing the relative abundance of polymers in freshwaters and estuaries. The polymers were identified according to seven main categories: polyethylene terephth...
Article
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Bovington Camp has been a main training area for armoured vehicles since 1916. Over the years, this has resulted in the erosion and mobilisation of soil particles into watercourses draining the area. Sediment-rich water from a main tributary, the Bovington Stream, discolours the River Frome during high flows. Regulatory agencies and angling groups...
Article
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The growing use of functional traits in ecological research has brought new insights into biodiversity responses to global environmental change. However, further progress depends on overcoming three major challenges involving (1) statistical correlations between traits, (2) phylogenetic constraints on the combination of traits possessed by any sing...
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Biological invasions represent a complex phenomenon driven by multiple factors. In this study, a real-time invasion process between a native (Pon-tastacus leptodactylus) and an invasive (Faxonius limosus) crayfish species was investigated in the Lower Danube (South-East Europe) through an inter-disciplinary approach, by measuring various ecological...
Article
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Understanding juvenile salmonid habitat requirements is critical for their effective management, but little is known about these requirements in lowland rivers, which include important but unique salmonid habitats. We compared the relative influence of in‐stream Ranunculus cover, water depth, prey abundance, distance upstream and two previously une...
Article
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Classical biomonitoring techniques have focused primarily on measures linked to various biodiversity metrics and indicator species. Next-generation biomonitoring (NGB) describes a suite of tools and approaches that allow the examination of a broader spectrum of organizational levels—from genes to entire ecosystems. Here, we frame 10 key questions t...
Technical Report
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Pollution from abandoned non-coal (i.e. metal) mines is a serious impediment to rivers meeting the water quality targets set out in River Basin Management Plans. Recent work has identified the mines most likely to be causing a significant environmental impact and hence where efforts to prevent pollution need to be focussed. Yet, it is not clear to...
Article
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Two complementary approaches are commonly used for analysing trophic interactions that allow inferences about consumed and assimilated resources: gut content (GCA) and stable isotope (SIA) analyses. We used these methods to assess the trophic ecology of a native (Pontastacus leptodactylus) and an invasive species (Faxonius limosus) of crayfish in t...
Article
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Over the last decade, steady advancements have been made in the use of DNA-based methods for detection of species in a wide range of ecosystems. This progress has culminated in molecular monitoring methods being employed for the detection of several species for enforceable management purposes of endangered, invasive, and illegally harvested species...
Article
Two complementary approaches are commonly used for analysing trophic interactions that allow inferences about consumed and assimilated resources: gut content (GCA) and stable isotope (SIA) analyses. We used these methods to assess the trophic ecology of a native (Pontastacus leptodactylus) and an invasive species (Faxonius limosus) of crayfish in t...
Article
Full-text available
Small, 1st and 2nd-order, headwater streams and ponds play essential roles in providing natural flood control, trapping sediments and contaminants, retaining nutrients, and maintaining biological diversity, which extend into downstream reaches, lakes and estuaries. However, the large geographic extent and high connectivity of these small water bodi...
Data
Example on-farm mitigation measures targeting different components of the water pollution cascade.
Article
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Current biomonitoring approaches are widely used but have some limitations. • DNA metabarcoding provides a new complementary tool for biomonitoring. • Metabarcoding allows extending the range of taxa used as bioindicators. • Metabarcoding data could be used to establish molecular metrics and indices. • Future work should standardise procedures and...
Article
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Body mass–abundance (M‐N) allometries provide a key measure of community structure, and deviations from scaling predictions could reveal how cross‐ecosystem subsidies alter food webs. For 31 streams across the UK, we tested the hypothesis that linear log‐log M‐N scaling is shallower than that predicted by allometric scaling theory when top predator...
Data
This two-page policy overview of problems for small water bodies and management options to address them accompanies the paper by Riley et al. (2018)
Article
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Diffuse water pollution from agriculture (DWPA) is a major environmental concern, with significant adverse impacts on both human and ecosystem health. However, without an appropriate understanding of the multiple factors impacting on water, mitigation measures cannot be targeted. Therefore, this paper addresses this gap in understanding, reporting...
Article
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Perennial rivers and streams make a disproportionate contribution to global carbon (C) cycling. However, the contribution of intermittent rivers and ephemeral streams (IRES),which sometimes cease to flow and can dry completely, is largely ignored although theymay represent over half the global river network. Substantial amounts of terrestrialplant...
Article
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In the version of this Article originally published, the affiliation for M. I. Arce was incorrect; it should have been: ⁵Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany. This has now been corrected in the online versions of the Article.
Article
Assessment of ecological status for the European Water Framework Directive (WFD) is based on "Biological Quality Elements" (BQEs), namely phytoplankton, benthic flora, benthic invertebrates and fish. Morphological identification of these organisms is a time-consuming and expensive procedure. Here, we assess the options for complementing and, perhap...
Article
Diffuse pollution of watercourses from agriculture represents a complex and persistent environmental problem in the UK. This paper provides insights into why UK policy interventions have had limited success to date, drawing on the disciplines of psychology, sociology and behavioural economics to more thoroughly understand farmer attitudes and behav...
Chapter
Metal-rich sediments have the potential to impair life in freshwater streams and rivers and, thereby, to inhibit recovery of ecological conditions after any remediation of mine water discharges. Sediments remain metal-rich over long time periods and have long-term potential ecotoxicological interactions with local biota, unless the sediments themse...
Article
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Floodplain meadows adjacent to the River Frome (Dorset UK) were subject to an agri-environment scheme designed to encourage beneficial management practices with the uptake of options designed to improve the environmental quality of ditches. The Rushton Ditch was dredged from source to mouth in October 2015 with vegetation removed from both banks. T...
Article
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Globally, salmon populations are under pressure and in those where numbers are severely depleted, density independent factors such as the accumulation of fine sediment and subsequent mortality of incubating embryos are critical factors in their conservation. Although progress has been made in identifying the processes by which fine sediment can lea...
Article
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Excessive inputs of fine-grained sediment can damage aquatic ecosystems both by degrading habitat condition and by directly impairing biota. Recent research has improved our understanding of how benthic macroinvertebrates respond to fine-grained sediment stress, leading to the development of a variety of bioassessment indices based on changes in ta...
Article
Excessive delivery of fine sediments to water bodies has a detrimental impact on the biotic elements used for water body status classification. Although diatoms are typically used to assess stress from eutrophication, as fine sediment has the potential to impact diatoms in many ways, it is not surprising that an index based on benthic diatom assemb...
Article
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Mitigation of diffuse water pollution from agriculture is a key national environmental policy objective in England. With the recent introduction of the new agri-environment scheme, Countryside Stewardship, there is an increased emphasis on the macro-spatial targeting of on-farm mitigation measures to reduce pollutant pressures, and a concomitant ne...
Article
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A multi-pollutant modelling framework for England and Wales is described. This includes emissions of nitrate, phosphorus and sediment to water and ammonia, methane and nitrous oxide to air, and has been used to characterise baseline (no uptake of on-farm measures) and business-as-usual (BAU) annual pollutant losses, comparing these with the loss un...
Article
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The protection, preservation and restoration of aquatic ecosystems and their functions are of global importance. For European states it became legally binding mainly through the EU-Water Framework Directive (WFD). In order to assess the ecological status of a given water body, aquatic biodiversity data are obtained and compared to a reference water...
Article
Fine sediment inputs from agricultural sources are a potential threat to freshwater ecosystems and may impact on the ability of EU members’ states to achieve environmental targets under the Water Framework Directive (WFD). An index (the Agricultural Sediment Risk index or ASR) representing the risk of agricultural fine sediment accumulation in riv...
Article
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The biotic resistance hypothesis provides one of several explanations for the limited biological recovery of streams recovering chemically from acidification. The hypothesis proposes that acidification has changed the presence, abundance and interactions among species in acidified streams to the extent that acid-sensitive colonists cannot re-invade...
Article
Improved water quality, through a reduction in diffuse pollution from agricultural sources, is an expected benefit of agri-environment schemes, but this has yet to be demonstrated in practice. Here we evaluate the impact of Welsh agri-environment schemes on water quality and freshwater ecosystem condition through a combined monitoring and modelling...
Article
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Brown trout, Salmo trutta, exhibit one of the most highly variable and polytypic life-history strategies of all salmonids. Populations may be wholly freshwater-resident or almost exclusively migratory (anadromous), or fish of a single population may exhibit varying proportions of the two life-history strategies. Both anadromous and freshwater-resid...
Article
River regulation and altered land use are common anthropogenic disturbances resulting in ecological impacts through siltation or altered hydrology. We tested the separate and combined effects of increased flow and fine particles (colmation) on macroinvertebrates in flume mesocosms. We hypothesised that increased flow would reduce any effects of col...
Article
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Declining water quality and ecological condition is a typical trend for rivers and streams worldwide as human demands for water resources increase. Managing these natural resources sustainably is a key responsibility of governments. Effective water management policies require information derived from long-term monitoring and evaluation. Biological...
Article
Detrimental impacts of excessive fine-grained sediment inputs to streams and rivers are well established. What is less well understood is the susceptibility of different elements of the freshwater biota to such perturbations and how such knowledge of their susceptibility could aid in identifying where excessive fine-grained sediment is impairing ec...
Article
River regulation and altered land use are two common anthropogenic disturbances in rivers worldwide. Alteration of the stream bed, through processes such as siltation, or of hydrology through river regulation, are likely to modify hyporheic processes or clog interstitial space and thereby affect both hyporheic invertebrates and nutrient dynamics.We...
Article
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Salmonids clean river bed gravels to lay their eggs. However, during the incubation period fine sediment infiltrates the bed. This has been found to limit the success of salmonid spawning, as fine sediment reduces gravel permeability resulting in intra-gravel flow velocities and O2 concentrations decreasing. The success of salmonid spawning is ther...
Article
Despite increasing concerns about the negative effects that increased loads of fine-grained sediment are having on freshwaters, the need is clear for a rapid and cost-effective methodology that gives precise estimates of deposited sediment across all river types and that are relevant to morphological and ecological impact. To date few attempts have...
Article
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Freshwater aquifers are a major source of drinking water. They also possess unique assemblages of organisms. However, little is known about the distributional drivers of obligate groundwater organisms at the regional scale. We examined the distribution and composition of stygobiont assemblages in a complex geological setting and explored the relati...
Article
The biodegradation of organic matter ingressing spawning gravels in rivers exerts an oxygen demand which is believed to contribute to detrimental impacts on aquatic ecology including salmonids. Catchment management strategies therefore require reliable information on the key sources of sediment-bound organic matter. Accordingly, a novel source fing...
Article
Imbalances between the supply of elements from resources and their demand from consumers may constrain key ecological processes, such as growth and production. Most previous studies have estimated such stoichiometric imbalances between consumers and resources by inferring the diet of the former from functional classifications rather than by direct...
Article
Excessive mobilization and delivery of fine sediments to water bodies has detrimental impacts on those biotic elements used for waterbody status classification, including macroinvertebrates, fish and macrophytes. The relationship between fine sediment and diatoms is a reciprocal one, with diatoms influencing the production and retention of fine sed...