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Papers by alison dunn

Management of Biological Invasions

An array of vectors have been identified that pose a risk of spreading invasive alien species (IA... more An array of vectors have been identified that pose a risk of spreading invasive alien species (IAS), from personal protective equipment to large equipment such as vehicles and boats. Biosecurity practices that remove and/or kill IAS reduce the risk of accidental spread. The effectiveness of biosecurity protocols suitable for large equipment is little tested and requires development. One widely-used biosecurity method for large equipment is high-pressure hot water spray machines. This study tests the effectiveness of high-pressure hot water spray to induce mortality in two invasive aquatic plants: floating pennywort (Hydrocotyle ranunculoides) and Australian swamp-stonecrop (Crassula helmsii); and two invasive invertebrates: killer shrimp (Dikerogammarus villosus) and zebra mussel (Dreissena polymorpha) in field conditions. IAS were exposed to hot water spray for a range of durations (5-15 seconds) and from a range of distances (10-30 cm). Further treatments of up to 90 seconds were applied to C. helmsii. Complete survival of D. polymorpha, D. villosus and C. helmsii was seen in all control treatments following exposure to cold water spray. Hot water spray caused complete mortality of D. polymorpha and D. villosus at 10 cm for 15 seconds, demonstrating the effectiveness of the hot water treatment in inducing mortality. However, treatments were less effective when applied at longer distances and shorter durations. In contrast, hot water spray was ineffective in causing mortality in C. helmsii, even at 90 seconds of exposure. Fragmentation and complete mortality was seen in H. ranunculoides following exposure to hot and cold water spray, therefore the pressure of the spray was associated with H. ranunculoides mortality. The use of hot water spray is effective against the aquatic invasive animals tested here, however to ensure complete mortality, the importance of both duration and distance of hot water spray application is highlighted. Hot water spray did cause complete mortality in H. ranunculoides but not in C. helmsii, therefore the need for treatment water containment and safe disposal is paramount to prevent spread of potentially viable propagules.

Oecologia

Climate change is increasing water temperature and intensifying the incidence of cyanobacterial b... more Climate change is increasing water temperature and intensifying the incidence of cyanobacterial blooms worldwide. However, the combined effects of increased temperature and microcystin concentrations as co-stressors on survival and ecological processes in freshwater species are unclear. Here, using purified MC-LR and crude extract of toxigenic Microcystis aeruginosa, we tested the individual and combined effects of three water temperatures (15, 20, 25 °C) and a range of environmentally relevant concentrations of dissolved microcystin and crude extract (0.01–10 µg·L−1) on survival, growth inhibition, grazing and predation rates in three freshwater species: phytoplankton (Scenedesmus quadricauda), zooplankton (Daphnia pulex), and an invertebrate predator (Ischnura elegans). Purified MC-LR exerted a higher growth inhibitory effect on S. quadricauda compared to crude extract with the same concentration of MC-LR, while neither treatment affected its chlorophyll-a content or survival of D...

Animal Behaviour, 2020

The human-assisted movement of species beyond their native range facilitates novel interactions b... more The human-assisted movement of species beyond their native range facilitates novel interactions between invaders and native species that can determine whether an introduced species becomes invasive and the nature of any consequences for native communities. Avoiding costly interactions through recognition and avoidance can be compromised by the naïvety of native species to novel invaders and vice versa. We tested this hypothesis using the common wall lizard, Podarcis muralis, and the native lizard species with which it may now interact in Britain (common lizard, Zootoca vivipara, sand lizard, Lacerta agilis) and on Vancouver Island (northern alligator lizard, Elgaria coerulea) by exploring species' responses (tongue flicks, avoidance behaviour) to heterospecific scent cues in controlled experiments. The tongue flick response of P. muralis depended on the different species' scent, with significantly more tongue flicks directed to E. coerulea scent than the other species and the control. This recognition did not result in any other behavioural response in P. muralis (i.e. attraction, aggression, avoidance). Lacerta agilis showed a strong recognition response to P. muralis scent, with more tongue flicks occurring close to the treatment stimuli than the control and aggressive behaviour directed towards the scent source. Conversely, Z. vivipara spent less time near P. muralis scent cues than the control but its tongue flick rate was higher towards this scent in this reduced time, consistent with an avoidance response. There was no evidence of E. coerulea recognition of P. muralis scent in terms of tongue flicks or time spent near the stimuli, although the native species did show a preference for P. muralis-scented refuges. Our results suggest a variable response of native species to the scent of P. muralis, from an avoidance response by Z. vivipara that mirrors patterns of exclusion observed in the field to direct aggression observed in L. agilis and an ambiguous reaction from E. coerulea which may reflect a diminished response to a cue with a low associated cost. These results have significant implications for the invasive success and potential impacts of introduced P. muralis populations on native lizards.

Wetlands Ecology and Management, 2020

Biosecurity protocols designed to prevent further spread of invasive alien species have become a ... more Biosecurity protocols designed to prevent further spread of invasive alien species have become a key component of invader management strategies. Yet, the species-specific efficacy of many biosecurity treatments are frequently unclear or unknown. Invasive quagga, Dreissena bugensis, and zebra mussels, D. polymorpha, are a serious threat to freshwater ecosystems worldwide. Here, we examine the effectiveness of immersion (≤ 90 min) within 2% or 4% solutions for two commonly used disinfectants (Virasure® Aquatic and Virkon® Aquatic) to cause mortality of adult Dreissena bivalves. Further, we assessed the effectiveness of thermal treatments: steam spray (≥ 100 °C; ≤ 120 s); hot air (− 500 °C; ≤ 60 s); and dry ice exposure (− 78 °C; ≤ 300 g; 15 min). Complete mortality of D. polymorpha was observed following exposure to both disinfectants for 90 min, at both concentrations. However, high but incomplete mortality (40–90%) was recorded for D. bugensis across disinfectant treatments. For bot...

Scientific Reports, 2020

Biosecurity protocols designed to prevent the spread of invasive alien species (IAS) are now an e... more Biosecurity protocols designed to prevent the spread of invasive alien species (IAS) are now an essential aspect of IAS management. However, the effectiveness of various biosecurity treatments requires further exploration. Killer shrimp, Dikerogammarus villosus, a notoriously high impact and ecosystem destabilising invader, has rapidly spread across Europe, and is of concern to invade Northern America. In this study, we examine the effectiveness of three commonly used, broad-spectrum disinfectants to cause mortality of D. villosus: Virasure Aquatic, Virkon Aquatic, and Virkon S. Immersion and spray treatments of 1%, 2% and 4% disinfectant solutions were examined for applications of up to 300 secs immersion and for up to ten consecutive sprays. Furthermore, we assessed the effectiveness of steam (≥100 °C) treatments for up to 120 secs. For all disinfectants, immersion in 1% solutions caused 100% mortality at ≥120 secs. At higher concentrations, shorter immersion times caused complete...

Management of Biological Invasions, 2020

, N. (2020). Tomorrow Never Dies: biodegradation and subsequent viability of invasive macrophytes... more , N. (2020). Tomorrow Never Dies: biodegradation and subsequent viability of invasive macrophytes following exposure to aquatic disinfectants. Management of Biological Invasions.

Journal of Insect Conservation, 2017

diversity of types of acoustic pollution, and encourage further work regarding trophic interactio... more diversity of types of acoustic pollution, and encourage further work regarding trophic interactions with insects using a functional response approach.

Conservation Letters, 2016

According to the Convention on Biological Diversity, by 2020 invasive alien species (IAS) should ... more According to the Convention on Biological Diversity, by 2020 invasive alien species (IAS) should be identified and their impacts assessed, so that species can be prioritized for implementation of appropriate control strategies and measures put in place to manage invasion pathways. For one quarter of the IAS listed as the "100 of the world's worst" environmental impacts are linked to diseases of wildlife (undomesticated plants and animals). Moreover, IAS are a significant source of "pathogen pollution" defined as the human-mediated introduction of a pathogen to a new host or region. Despite this, little is known about the biology of alien pathogens and their biodiversity impacts after introduction into new regions. We argue that the threats posed by alien pathogens to endangered species, ecosystems, and ecosystem services should receive greater attention through legislation, policy, and management. We identify 10 key areas for research and action, including those relevant to the processes of introduction and establishment of an alien pathogen and to prediction of the spread and associated impact of an alien pathogen on native biota and ecosystems. The development of interdisciplinary capacity, expertise, and coordination to identify and manage threats was seen as critical to address knowledge gaps.

Biology Letters, 2010

Invasive species can have profound impacts on communities and it is increasingly recognized that ... more Invasive species can have profound impacts on communities and it is increasingly recognized that such effects may be mediated by parasitism. The ‘enemy release’ hypothesis posits that invaders may be successful and have high impacts owing to escape from parasitism. Alternatively, we hypothesize that parasites may increase host feeding rates and hence parasitized invaders may have increased community impacts. Here, we investigate the influence of parasitism on the predatory impact of the invasive freshwater amphipod Gammarus pulex . Up to 70 per cent of individuals are infected with the acanthocephalan parasite Echinorhynchus truttae , but parasitized individuals were no different in body condition to those unparasitized. Parasitized individuals consumed significantly more prey ( Asellus aquaticus ; Isopoda) than did unparasitized individuals. Both parasitized and unparasitized individuals displayed Type-II functional responses (FRs), with the FR for parasitized individuals rising mo...

Biological Invasions, 2019

Invasive alien species (IAS) can drive community change through ecological interactions. Parasite... more Invasive alien species (IAS) can drive community change through ecological interactions. Parasites and pathogens can play an important role in community function including mitigating or enhancing IAS impacts. Despite this, the degree to which pathogen pressure influences IAS impacts remains poorly understood. We quantified the predatory behaviour of the highly invasive alien harlequin ladybird (Harmonia axyridis) and two UK native species, the 7-spot (Coccinella septempunctata) and 2-spot (Adalia bipunctata) ladybirds, using comparative functional response experiments. We investigated the impacts of pathogen infection on the predatory ability of the ladybirds by exposing individuals to Beauveria bassiana, a widespread entomopathogen. Invasive H. axyridis was a more efficient predator than both the native A. bipunctata and C. septempunctata, often having higher attack and/or lower prey handling time coefficients, whereas native A. bipunctata were the least efficient predators. These differences were found in both adult and larval life-stages. Beauveria bassiana infection significantly altered the predatory efficiency of adult and larval ladybird predators. The effects of pathogenic infection differed between species and life-stage but in many cases infection resulted in a reduced predatory ability. We suggest that the interactions between IAS and pathogens are integral to determining invasion success and impact.

Applied and Environmental Microbiology, 2012

We designed fluorescence in situ hybridization probes for two distinct microsporidian clades and ... more We designed fluorescence in situ hybridization probes for two distinct microsporidian clades and demonstrated their application in detecting, respectively, Nosema / Vairimorpha and Dictyoceola species. We used them to study the vertical transmission of two microsporidia infecting the amphipod Gammarus duebeni .

Proceedings of the Royal Society B: Biological Sciences, 2003

Diversity

Signal crayfish, as an invasive alien species in Europe, have caused impacts on aquatic communiti... more Signal crayfish, as an invasive alien species in Europe, have caused impacts on aquatic communities and losses of native crayfish. Eradication of recently established populations may be possible in small ponds (<2.5 ha) and short lengths of small watercourses using a nonselective biocide. Between 2004 and 2012, a total of 13 sites in the U.K. were assessed for suitability. Six were treated with natural pyrethrum and crayfish were successfully eradicated from three. In Norway, five sites were assessed and two sites were treated with a synthetic pyrethroid, cypermethrin, both successfully. In Sweden, three sites were treated with another synthetic pyrethroid, deltamethrin, all successfully. Defining the likely extent of population was critical in determining the feasibility of treatment, as well as the ability to treat the whole population effectively. Important constraints on projects included site size, habitat complexity, environmental risks, cooperation of landowners and fundin...

Journal of invertebrate pathology, 2018

Invasive and non-native species can pose risks to vulnerable ecosystems by co-introducing bacteri... more Invasive and non-native species can pose risks to vulnerable ecosystems by co-introducing bacterial pathogens. Alternatively, co-introduced bacterial pathogens may regulate invasive population size and invasive traits. We describe a novel candidate genus and species of bacteria ('Candidatus Aquirickettsiella gammari') found to infect Gammarus fossarum, from its native range in Poland. The bacterium develops intracellularly within the haemocytes and cells of the musculature, hepatopancreas, connective tissues, nervous system and gonad of the host. The developmental cycle of 'Candidatus Aquirickettsiella gammari' includes an elementary body (496.73 nm ± 37.56 nm in length, and 176.89 nm ± 36.29 nm in width), an elliptical, condensed spherical stage (737.61 nm ± 44.51 nm in length and 300.07 nm ± 44.02 nm in width), a divisional stage, and a spherical initial body (1397.59 nm ± 21.26 nm in diameter). We provide a partial genome for 'Candidatus Aquirickettsiella gamm...

Journal of Applied Ecology

1. Predictions of the identities and ecological impacts of invasive alien species are critical fo... more 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 emerging and potential future invaders that have no invasion history. Such a metric would also ideally apply across diverse taxonomic and trophic groups. 2. We derive a new metric of invader ecological impact that blends: (i) the classic Functional Response (FR; consumer per capita effect) and Numerical Response (NR; consumer population response) approaches to determining consumer impact, that is, the Total Response (TR = FR 9 NR), with; (ii) the 'Parker-Lonsdale equation' for invader impact, where Impact = Range 9 Abundance 9 Effect (per capita effect), into; (iii) a new metric, Relative Impact Potential (RIP), where RIP = FR 9 Abundance. The RIP metric is an invader/native ratio, where values >1 predict that invader ecological impact will occur, and increasing values above 1 indicate increasing impact. In addition, the invader/invader RIP ratio allows comparisons of the ecological impacts of different invaders.

Parasites & vectors, Jan 20, 2017

Whilst vastly understudied, pathogens of non-native species (NNS) are increasingly recognised as ... more Whilst vastly understudied, pathogens of non-native species (NNS) are increasingly recognised as important threats to native wildlife. This study builds upon recent recommendations for improved screening for pathogens in NNS by focusing on populations of Gammarus roeselii in Chojna, north-western Poland. At this location, and in other parts of continental Europe, G. roeselii is considered a well-established and relatively 'low-impact' invader, with little understanding about its underlying pathogen profile and even less on potential spill-over of these pathogens to native species. Using a combination of histological, ultrastructural and phylogenetic approaches, we define a pathogen profile for non-native populations of G. roeselii in Poland. This profile comprised acanthocephalans (Polymorphus minutus Goese, 1782 and Pomphorhynchus sp.), digenean trematodes, commensal rotifers, commensal and parasitic ciliated protists, gregarines, microsporidia, a putative rickettsia-like o...

Parasitology, Feb 28, 1997

Http Dx Doi Org 10 1080 07924259 1994 9672378, Feb 25, 2011

ABSTRACT

Invertebr Reprod Dev, 2011

... 10.1080/07924259.2011.606176 Alex T. Ford a * , Irene Martins b &amp; Alison M. Dunn ... more ... 10.1080/07924259.2011.606176 Alex T. Ford a * , Irene Martins b &amp; Alison M. Dunn c Available online: 26 Aug 2011. ... Interestingly, the period of 6 days was less than the average pre-copular pairing period found by Elwood et al. (19875. Elwood, R, Gibson, J and Neil, S. 1987. ...