Browsing Environmental Sustainability Research Centre by Subjects
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Diseases in marine invertebrates associated with mariculture and commercial fisheriesDiseases in marine invertebrates are increasing in both frequency and intensity around the globe. Diseases in individuals which offer some commercial value are often well documented and subsequently well studied in comparison to those wild groups offering little commercial gain. This is particularly the case with those associated with mariculture or the commercial fisheries. Specifically, these include many Holothuroidea, and numerous crustacea and mollusca species. Pathogens/parasites consisting of both prokaryotes and eukaryotes from all groups have been associated with diseases from such organisms, including bacteria, viruses, fungi and protozoa. Viral pathogens in particular, appear to be an increasingly important group and research into this group will likely highlight a larger number of diseases and pathogens being described in the near future. Interestingly, although there are countless examples of the spread of disease usually associated with transportation of specific infected hosts for development of aquaculture practices, this process appears to be continuing with no real sign of effective management and mitigation strategies being implicated. Notably, even in well developed countries such as the UK and the US, even though live animal trade may be well managed, the transport of frozen food appears to be less well so and as evidence suggests, even these to have the potential to transmit pathogens when used as a food source for example.
First detection of a highly invasive freshwater amphipod Crangonyx floridanus (Bousfield, 1963) in the United Kingdom.The freshwater gammarid, Crangonyx floridanus, originates from North America but has invaded and subsequently spread rapidly throughout Japan. We provide here the first genetic and microscopic evidence that C. floridanus has now also reached the United Kingdom. We found this species in two locations separated by more than 200 km (Lake Windermere in the North of the UK and Smestow Brook, West Midlands). The current distribution of C. floridanus is currently unknown, however, both sites are well connected to other river and canal systems. Therefore, the chance of further spread is high. Genetic analyses of C. floridanus indicate that British inland waters are colonised by the same lineage, which invaded Japan. We recommend further work to assess the distribution of this species and its impact on the local fauna and flora.
Rediscovery of the critically endangered ‘scarce yellow sally stonefly’ Isogenus nubecula in United Kingdom after a 22 year period of absence.The critically endangered ‘scarce yellow sally stonefly’ Isogenus nubecula (Newman, 1833) (Plecoptera: Perlodidae) was rediscovered in the United Kingdom (UK) in 2017. This rediscovery comes after a 22-year period of absence despite numerous surveys since its last record in 1995. This species is one of the rarest stoneflies in the UK and Europe and its rediscovery is of international significance, being the westernmost point in Europe where the species is found, with the next nearest populations occurring in Austria and western Hungary, Slovakia, and central Sweden. The species is classed as pRDB2 (vulnerable), however is not listed in the British Red Data Book despite only being present (as far as records detail) in one river, the River Dee in North Wales, UK. Only fourteen individuals were caught and the need for conservation of this rare stonefly is therefore of paramount importance. We have made recommendations for the need to increase survey effort using environmental DNA (eDNA) techniques in order to fully understand the species range in this river and those in the surrounding area. The DNA sequence of I. nubecula has been uploaded on GenBank for further genetic studies. Captive rearing could also be explored with possible reintroductions to sites within its former UK range.
Species effects on ecosystem processes are modified by faunal responses to habitat composition.Heterogeneity is a well-recognized feature of natural environments, and the spatial distribution and movement of individual species is primarily driven by resource requirements. In laboratory experiments designed to explore how different species drive ecosystem processes, such as nutrient release, habitat heterogeneity is often seen as something which must be rigorously controlled for. Most small experimental systems are therefore spatially homogeneous, and the link between environmental heterogeneity and its effects on the redistribution of individuals and species, and on ecosystem processes, has not been fully explored. In this paper, we used a mesocosm system to investigate the relationship between habitat composition, species movement and sediment nutrient release for each of four functionally contrasting species of marine benthic invertebrate macrofauna. For each species, various habitat configurations were generated by selectively enriching patches of sediment with macroalgae, a natural source of spatial variability in intertidal mudflats. We found that the direction and extent of faunal movement between patches differs with species identity, density and habitat composition. Combinations of these factors lead to concomitant changes in nutrient release, such that habitat composition effects are modified by species identity (in the case of NH4-N) and by species density (in the case of PO4-P). It is clear that failure to accommodate natural patterns of spatial heterogeneity in such studies may result in an incomplete understanding of system behaviour. This will be particularly important for future experiments designed to explore the effects of species richness on ecosystem processes, where the complex interactions reported here for single species may be compounded when species are brought together in multi-species combinations.