Calum Macneil

Calum Macneil
Cawthron Institute | CI · Freshwater Ecosystems

PhD

About

91
Publications
26,087
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Introduction
Govt. senior scientist responsible for catchment management, biological/chemical monitoring rivers, freshwater policy, discharge licences, abstractions, infrastructure/planning consents, freshwater/coastal research, bathing water quality monitoring, environmental impact assessments, pollution control and enforcement, WFD. Expert in invasive species, water quality monitoring programmes and science communication/stakeholder involvement in integrated catchment management. Deputy Editor-in-Chief - Management of Biological Invasions' Associate Editor - Aquatic Invasions, Biological Invasions Records. Currently working on pollution monitoring, 'killer shrimp', low flow/drought ecology and freshwater policy papers

Publications

Publications (91)
Article
Biological invasions are global threats to biodiversity and parasites might play a role in determining invasion outcomes. Transmission of parasites from invading to native species can occur, aiding the invasion process, whilst the 'release' of invaders from parasites can also facilitate invasions. Parasites might also have indirect effects on the o...
Article
Gammarus spp. are widespread throughout a diverse range of freshwater habitats and can be the dominant part of many benthic macroinvertebrate assemblages, in terms of both numbers and/or biomass. Although the vast majority of studies have emphasized the herbivorous nature of Gammarus spp. and their ‘shredder’ functional feeding group (FFG) classifi...
Article
Full-text available
1. Predictions of the identities and ecological impacts of invasive alien species are critical for risk assessment, but presently we lack universal and standardized metrics that reliably predict the likelihood and degree of impact of such invaders (i.e. measureable changes in populations of affected species). This need is especially pressing for em...
Article
Full-text available
Single-author papers are the lowest relative contributors to the research output of international open access journals BioInvasions Records (BIR), Aquatic Invasions (AI) and Management of Biological Invasions (MBI), accounting for 5% or less of published papers. In contrast, papers by four or more authors are the highest contributors, accounting fo...
Article
Non-consumptive effects (NCEs) of predators – so called ‘fear’ responses – encompass costly antipredator behaviours, such as reduced feeding efficiency. NCEs can influence prey population dynamics and community structure, if prey are ‘keystone’ species such as Gammarus spp. amphipod ‘shrimps’. These freshwater macroinvertebrates have the ecosystem...
Technical Report
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Easy to use introductory guide for citizen science / catchment groups to monitor river water quality in their local area.
Technical Report
Full-text available
A comprehensive water quality monitoring framework for citizen science / catchment groups to monitor water quality in their local rivers and streams.
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Until the 2000s, faunal exchange between endemic faunas of the Caspian Sea basin and the Azov-Black Sea (aka Pontic) basin was asymmetrical, with fauna heading towards the Volga Delta and Caspian Sea from or via the Black and Azov Seas and little exchange in the opposite direction. This study is based on a hydrobiological survey of the Don River Ba...
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The Ponto-Caspian amphipod Dikerogammarus villosus has invaded Central European and British freshwaters and its arrival is associated with biodiversity decline, as D. villosus is predatory towards many macroinvertebrate taxa, including resident amphipods such as Crangonyx pseudogracilis and isopods such as Asellus aquaticus. I investigated how diff...
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It has been hypothesised that freshwater pollution may favour the establishment of tolerant invaders at the expense of less-tolerant residents. To test this, this study capitalises on the aftermath of a farm pollution incident, a slurry discharge to a small British stream, which eliminated the resident macroinvertebrate assemblage. Stream transplan...
Article
Invasive species can have profound impacts on the structure of resident assemblages through biotic interactions. This can only be realistically assessed when pre-invasion scenarios are available for comparative purposes and environmental regimes remain relatively constant. In 1949, the ecologist H.B.N. Hynes noted an almost discrete distribution ex...
Article
The ability to track changing distributions and long-term interactions between native and introduced species provides insights into forecasting impacts of invaders. We used data from deliberate field introduction experiments of a freshwater Gammarus amphipod (Crustacea) to the rivers of a small British island, The Isle of Man. The deliberate introd...
Article
1. Predictions of the identities and ecological impacts of invasive alien species are critical for risk assessment, but presently we lack universal and standardized metrics that reliably predict the likelihood and degree of impact of such invaders (i.e. measurable changes in populations of affected species). This need is especially pressing for eme...
Technical Report
Full-text available
To provide a 'snapshot' of how diffuse pollution may be impacting on river sites immediately adjacent to monitored sea bathing beach sites and thereby potentially influencing bathing water quality, during Summer/Autumn 2016, water samples from 21 river sites were analysed for microbiological parameters (coliforms and faecal streptococci) relevant t...
Article
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Freshwater biodiversity and ecosystem integrity are under threat from biological invasions. The “killer shrimp” Dikerogammarus villosus is a highly predatory amphipod that has spread readily across Central Europe and recently the UK and its arrival has been associated with the significant loss of resident species. Despite this, studies of its behav...
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Understanding and predicting the outcomes of biological invasions is challenging where multiple invader and native species interact. We hypothesize that antagonistic interactions between invaders and natives could divert their impact on subsequent invasive species, thus facilitating coexistence. From field data, we found that, when existing togethe...
Article
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The 'killer shrimp', Dikerogammarus villosus, has been recognised as one of the 100 worst alien species in Europe, in terms of negative impacts on the biodiversity and functioning of invaded ecosystems. During the last twenty years, this Ponto-Caspian amphipod crustacean has rapidly spread throughout Europe's freshwaters and its invasion and contin...
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Short Communication CORRECTED PROOF "The pump don't work, 'Cause the vandals took the handles"; why invasive amphipods threaten accurate freshwater biological water quality monitoring Abstract The 2010 invasion of Great Britain by the eastern European 'killer shrimp' Dikerogammarus villosus (Crustacea: Amphipoda) was just the latest of several amph...
Article
Patterns of coexistence and exclusion among resident and invading species in freshwaters may be generated by direct biotic interactions well as by indirect interactions with the broader abiotic and biotic environments. The North American ‘shrimp’ Crangonyx pseudogracilis (Crustacea: Amphipoda) is invasive in Europe where it forms complex patterns o...
Technical Report
Full-text available
Chemical water quality data for summers from 1999 to 2013 are presented in the form of quality classifications, showing trends in the water quality of Manx rivers. Government Laboratory Thie-scroodee-stoo yn Reiltys Ballakermeen Road, Isle of Man, IM1 4BR.
Article
The ability to predict the likely ecological impacts of invasive species in fresh waters is a pressing research requirement. Whilst comparisons of species traits and considerations of invasion history have some efficacy in this respect, we require robust methods that can compare the effects of native and invasive species. Here, we utilise comparati...
Technical Report
Full-text available
This report summarises pollution trends from 1997-2013, while providing an analysis of pollution incidents reported during 2013. Similar to all previous years, river pollution incidents were reported by Government employees, members of the public, police, MHKs and conservation groups. These reports provide a basis for a water pollution archive, whi...
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The success of invading species can be restricted by interspecific interactions such as competition and predation (i.e. biotic resistance) from resident species, which may be natives or previous invaders. Whilst there are myriad examples of resident species preying on invaders, simply showing that such an interaction exists does not demonstrate tha...
Article
Linkages between habitat structure, invasibility and direct species interactions were examined in a Central European river system, the Schipbeek in the Netherlands, invaded by the ‘killer shrimp’ amphipod Dikerogammarus villosus. The invader's arrival in other fresh waters is linked to declines in macroinvertebrate biodiversity, with previous studi...
Technical Report
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Article
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1. Water quality monitoring data from 10 watercourses and laboratory mesocosm studies were used to assess the potential impacts of the crustacean amphipod invader Dikerogammarus villosus on resident macroinvertebrate assemblage structure in Central European fresh waters. 2. The presence of D. villosus was associated with a decline in the prevalence...
Article
Macroinvertebrates are routinely used in the calculation of indices to assess the quality of rivers throughout the world. Macroinvertebrate assemblages have proved themselves to be reliable, cost effective indicators of freshwater pollution, as the relative sensitivities of their members respond to changes in water quality in predictable ways. Such...
Article
Full-text available
In 2010, the ‘killer shrimp’ Dikerogammarus villosus (Crustacea: Amphipoda) invaded the British Isles. Past research from central Europe has shown this eastern European shrimp invader to be a ‘voracious omnivore’, highly predatory of a wide range of freshwater macroinvertebrate taxa and also fish fry. It can become ‘super-abundant’ within invaded s...
Article
Species–environment gradients are ubiquitous in nature, with studies often partially explaining the replacement of species along such gradients by autecological factors such as differential physiological tolerances. However, lacking direct evidence, the majority of studies only infer some form of inter-specific interaction, often competition, as re...
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Introduced predators can have profound impacts on prey populations, with subsequent ramifications throughout entire ecosystems. However, studies of predator–prey interaction strengths in community and food-web analyses focus on adults or use average body sizes. This ignores ontogenetic changes, or lack thereof, in predatory capabilities over the li...
Article
Full-text available
In 2010, the 'killer shrimp' Dikerogammarus villosus (Crustacea: Amphipoda) invaded the British Isles. Past research from central Europe has shown this eastern European shrimp invader to be a 'voracious omnivore', highly predatory of a wide range of freshwater macroinvertebrate taxa and also fish fry. It can become 'super-abundant' within invaded s...
Technical Report
Full-text available
The last river pollution incidents report/summary for the Isle of Man was produced in 2004 and summarized pollution trends from 1997-2003 inclusive and provided an in-depth analysis of pollution incidents on the Island during the calendar year 2003. This current report follows a similar format to that one and indeed all the previous reports produce...
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Parasitism is emerging as one of the forces determining the outcome of biological invasions. Using field survey and laboratory experiments, we investigate parasitism as one of the factors mediating the interactions among invasive and native amphipods. An extensive survey (100 sites) of a small British island, revealed the native Gammarus duebeni ce...
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We assessed the extent to which an invader, Gammarus pulex (Crustacea: Amphipoda), has replaced a native, Gammarus duebeni celticus, over a 13-year period in a European river system and some of the abiotic and biotic factors that could account for this. Between 1988 and 2001, 56% of mixed-species sites had become invader-only sites, whereas no mixe...
Article
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Animal introductions can often have unexpected and complex consequences for both native and invader species. Freshwater crustaceans such as Gammarus spp. (amphipods) and Mysis relicta (an ‘opossum shrimp’) have frequently come into contact because of deliberate and accidental introductions. However, there remains poor understanding of mechanisms le...
Article
Invasive species may threaten the fundamental role played by native macroinvertebrate shredders in determining energy flow and the trophic dynamics of freshwater ecosystems. Functionally, amphipods have long been regarded as mainly shredders, but they are increasingly recognized as major predators of other macroinvertebrate taxa. Furthermore, intra...
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This report critically assesses the concept of ecological integrity (EI) and its application in freshwater management. EI integrates a wide range of ecological values related to the structural and functional processes of ecosystems, making it particularly appealing for management application. EI is not inherently empirical, but it can be useful whe...
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Freshwater invasive or alien species (IAS) can have a major impact on benthic macroinvertebrate assemblage structure and diversity. This has implications for accurate biological monitoring, the assessment of the ecological quality status of rivers and achievement of Water Framework Directive (WFD) objectives. Although IAS constitutes a major biolog...
Article
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The Ponto-Caspian amphipod Dikerogammarus villosus was found both in the margins and open water areas of Grafham Water, a large reservoir in Cambridgeshire, U.K., in September 2010. Both adults and juveniles were present in large numbers and were most frequent in the boulder/cobble areas dominating the margins of the reservoir. Precopula pairs were...
Technical Report
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Summary of changing chemical and biological water quality in Isle of Man rivers, covering the timespan 1995-2009.
Article
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Invasive species and environmental change often occur simultaneously across a habitat and therefore our understanding of their relative roles in the decline of native species is often poor. Here, the environmental mediation of a critical interspecific interaction, intraguild predation (IGP), was examined between invasive (Gammarus pulex) and native...
Article
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As biological invasions continue, interactions occur not only between invaders and natives, but increasingly new invaders come into contact with previous invaders. Whilst this can lead to species replacements, co-existence may occur, but we lack knowledge of processes driving such patterns. Since environmental heterogeneity can determine species ri...
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The rate of freshwater invasions may be increasing, and macroinvertebrate invaders can have significant impacts on native macroinvertebrate assemblage structure through biotic interactions. More pollution-tolerant invaders can often replace native species. We examined implications of a species replacement for accurate biological monitoring of river...
Article
Aim Using data from field introduction experiments with Gammarus spp. conducted in the rivers of a small island, commencing in 1949, with resampling in the 60s, 70s, 80s, 90s and finally in 2005, we aimed to examine the long-term interaction of the native freshwater amphipod Gammarus duebeni celticus with the introduced G. pulex. Using physico-chem...
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Cannibalism and intraguild predation (IGP) are common amongst freshwater amphipod crustacean aswsemblages, particularly between individuals of different body size, with IGP of smaller by larger species. The decline of Gammarus tigrinus populations in mainland Europe has been accompanied by the arrival of the Ponto-Caspian invader Dikerogammarus vil...
Article
Assessing the effects of invading species on native community structure is often confounded by environmental factors and weakened by lack of replicated, long-term pre- and post-invasion monitoring. Here, we uncouple the community effects of a freshwater amphipod invader from environmental differences. In Irish rivers, the introduced Gammarus pulex...
Article
Sexual cannibalism, where a female kills and consumes a courting male, represents an extreme form of sexual conflict and has been proposed as a mechanism of mate choice. We evaluate the evidence for mate choice through premating sexual cannibalism via mate rejection, other indirect mechanisms of mate ‘choice’ and choice in postmating sexual canniba...
Article
In Northern Ireland, the native Gammarus duebeni celticus and introduced Gammarus tigrinus occur in the same river and lake systems. This study examined the outcome of encounters between the two amphipod species in the same patch of lake/pooled area of river. A laboratory simulation of a lake/river habitat indicated that G. d. celticus and G. tigri...
Article
Full-text available
Predation between invading and native species can produce patterns of exclusion and coexistence. Dikerogammarus villosus, a Ponto-Caspian amphipod species, has invaded many central European freshwaters in the past decade, replacing native Gammarus amphipod species. For instance, the arrival of D. villosus in Holland has been accompanied by the decl...
Technical Report
Full-text available
state of environment report on water qulaity (chemical/biological) of Isle of Man rivers, with additional chapter on mine pollution impacts.
Technical Report
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Survey of river habitats of the Isle of Man
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The microsporidian parasite, Pleistophora mulleri, infects the abdominal muscle of the freshwater amphipod Gammarus duebeni celticus. We recently showed that P. mulleri infection was associated with G. d. celticus hosts being more vulnerable to predation by the invasive amphipod Gammarus pulex. Parasitized G. d. celticus also had a reduced ability...
Article
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Interspecific interactions are major structuring forces in marine littoral communities; however, it is unclear which of these interactions are exhibited by many key-component species. Gut content analysis showed that the ubiquitous rocky/cobble shore amphipod Echinogammarus marinas, often ascribed as a mesograzer, consumes both algae and macroinver...
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Vertical transmission (VT) and associated manipulation of host reproduction are widely reported among prokaryotic endosymbionts. Here, we present evidence for widespread use of VT and associated sex-ratio distortion in a eukaryotic phylum. The Microspora are an unusual and diverse group of eukaryotic parasites that infect all animal phyla. Followin...
Article
With field, laboratory, and modeling approaches, we examined the interplay among habitat structure, intraguild predation (IGP), and parasitism in an ongoing species invasion. Native Gammarus duebeni celticus (Crustacea: Amphipoda) are often, but not always, replaced by the invader Gammarus pulex through differential IGP. The muscle-wasting microspo...
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In lethal and sublethal ammonia toxicity tests, we examined differences in tolerance of three species of freshwater amphipods, one native and two invasive in Ireland. The native Gammarus duebeni celticus was slightly less tolerant to ammonia than the invasive G. pulex (96 h LC50= 1.155 and 1.544 mg l(-1), respectively), while another invader, Crang...
Article
1. The balance of predation between closely related invasive and native species can be an important determinant of the success or failure of biological invasions. In Irish freshwaters, the introduced amphipod Gammarus pulex has replaced the native G. duebeni celticus, possibly through differential mutual intraguild predation (IGP). Theoretically, p...
Article
In its freshwater amphipod host Gammarus duebeni celticus, the microsporidian parasite Pleistophora mulleri showed 23% transmission efficiency when uninfected individuals were fed infected tissue, but 0% transmission by water-borne and coprophagous routes. Cannibalism between unparasitised and parasitised individuals was significantly in favour of...
Article
Invading and native species often interact directly, such as by predation, producing patterns of exclusion and coexistence. Less direct factors, such as interactions with the broader abiotic and biotic environment, may also contribute to such patterns, but these have received less recognition. In Northern Ireland, the North American Gammarus tigrin...
Article
Full-text available
Parasites can structure biological communities directly through population regulation and indirectly by processes such as apparent competition. However, the role of parasites in the process of biological invasion is less well understood and mechanisms of parasite mediation of predation among hosts are unclear. Mutual predation between native and in...
Article
The classification of a microsporidian parasite observed in the abdominal muscles of amphipod hosts has been repeatedly revised but still remains inconclusive. This parasite has variable spore numbers within a sporophorous vesicle and has been assigned to the genera Glugea, Pleistophora, Stempellia, and Thelohania. We used electron microscopy and m...
Article
Studies of invasion scenarios over long time periods are important to refine explanations and predictions of invasion success and impact. We used data from surveys in 1958 and 1999 of the macroinvertebrates of Lough Neagh, Northern Ireland, to assess changes in the distribution of native and introduced amphipods in relation to the wider assemblage....