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565 results on '"Johnston, Emma L."'

9. A global horizon scan of issues impacting marine and coastal biodiversity conservation

Author

Herbert-Read, James E., Thornton, Ann, Amon, Diva J., Birchenough, Silvana N. R., Côté, Isabelle M., Dias, Maria P., Godley, Brendan J., Keith, Sally A., McKinley, Emma, Peck, Lloyd S., Calado, Ricardo, Defeo, Omar, Degraer, Steven, Johnston, Emma L., Kaartokallio, Hermanni, Macreadie, Peter I., Metaxas, Anna, Muthumbi, Agnes W. N., Obura, David O., Paterson, David M., Piola, Alberto R., Richardson, Anthony J., Schloss, Irene R., Snelgrove, Paul V. R., Stewart, Bryce D., Thompson, Paul M., Watson, Gordon J., Worthington, Thomas A., Yasuhara, Moriaki, and Sutherland, William J.

Published
2022
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13. Structural and functional effects of global invasion pressure on benthic marine communities—patterns, challenges and priorities.

Author

Zaiko, Anastasija, Cardeccia, Alice, Carlton, James T., Clark, Graeme F., Creed, Joel C., Davidson, Ian, Floerl, Oliver, Galil, Bella, Grosholz, Edwin, Hopkins, Grant A., Johnston, Emma L., Kotta, Jonne, Marchini, Agnese, Ojaveer, Henn, Ruiz, Gregory, Therriault, Thomas W., and Inglis, Graeme J.

Subjects
BIOLOGICAL invasions, BIOTIC communities, INTRODUCED species, MARINE ecology, COMMUNITY change, ECOSYSTEMS
Abstract

Aim: Retrospective (pre‐ vs. post‐invasion) and cross‐sectional comparisons of ecosystems exposed to high and low bioinvasion pressure, provide an alternative approach to evaluate shifts in biological communities associated with non‐indigenous species (NIS) introductions. In this study, we aimed to examine general patterns of change in community composition, structure and function in six well‐studied and globally distributed marine ecosystems that had documented histories of biological invasions. Location: Global. Methods: By considering a range of regional datasets and different sampling approaches, we evaluated trends within and among ecosystems by comparing paired measures of community and functional structure in either space or time. Results: Our analyses revealed different patterns of structural and functional change at ecosystem scales, but direct comparisons across regions were hindered by confounding effects of study designs and other drivers of change. The most prominent shifts in community composition were observed in the retrospective studies, characterised by the greatest relative contribution of NIS. No uniform pattern of change in functional metrics was observed across study regions. However, functional evenness and dispersion showed a tendency to increase in systems under higher invasion pressure, refuting the hypothesis of selective accumulation of specific traits and functional homogenisation within ecosystems exposed to high invasion pressure. Main Conclusions: Accumulation of NIS within broader communities can be a subtle process, with inherent spatial and temporal variability. Nonetheless, not only do species' proportional contributions to communities change over time in areas subjected to high bioinvasion pressure, but trait profiles can incrementally shift, which alters the original ecology of an area. Planned, long‐term studies that incorporate a range of measures of environmental drivers and ecosystem response are crucial for better understanding of cumulative, community‐level and ecosystem‐scale change associated with biological invasions. [ABSTRACT FROM AUTHOR]

Published
2024
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22. Invasion Expansion: Time since introduction best predicts global ranges of marine invaders.

Author

Byers, James E, Smith, Rachel S, Pringle, James M, Clark, Graeme F, Gribben, Paul E, Hewitt, Chad L, Inglis, Graeme J, Johnston, Emma L, Ruiz, Gregory M, Stachowicz, John J, and Bishop, Melanie J

Subjects
Animals, Invertebrates, Marine Biology, Environment, Ecosystem, Time Factors, Ships, Databases, Factual, United States, Australia, New Zealand, Introduced Species, Aquatic Organisms, Databases, Factual
Abstract

Strategies for managing biological invasions are often based on the premise that characteristics of invading species and the invaded environment are key predictors of the invader's distribution. Yet, for either biological traits or environmental characteristics to explain distribution, adequate time must have elapsed for species to spread to all potential habitats. We compiled and analyzed a database of natural history and ecological traits of 138 coastal marine invertebrate species, the environmental conditions at sites to which they have been introduced, and their date of first introduction. We found that time since introduction explained the largest fraction (20%) of the variability in non-native range size, while traits of the species and environmental variables had significant, but minimal, influence on non-native range size. The positive relationship between time since introduction and range size indicates that non-native marine invertebrate species are not at equilibrium and are still spreading, posing a major challenge for management of coastal ecosystems.

Published
2015

33. An expert-driven framework for applying eDNA tools to improve biosecurity in the Antarctic

Author

Clarke, Laurence J., Shaw, Justine D., Suter, Leonie, Atalah, Javier, Bergstrom, Dana M., Biersma, Elisabeth Machteld, Convey, Peter, Greve, Michelle, Holland, Oakes, Houghton, Melissa J., Hughes, Kevin A., Johnston, Emma L., King, Catherine K., McCarthy, Arlie H., McGaughran, Angela, Pertierra, Luis R., Robinson, Sharon A., Sherman, Craig D.H., Stark, Jonathan S., Stevens, Mark I., Strugnell, Jan M., von Ammon, Ulla, Wilson, Nerida G., Zaiko, Anastasija, MacDonald, Anna J., and Universidad de Alicante. Departamento de Ciencias del Mar y Biología Aplicada

Subjects
Marine, Biofouling, Non-native species, Environmental DNA, Terrestrial, Southern Ocean
Abstract

Signatories to the Antarctic Treaty System’s Environmental Protocol are committed to preventing incursions of non-native species into Antarctica, but systematic surveillance is rare. Environmental DNA (eDNA) methods provide new opportunities for enhancing detection of non-native species and biosecurity monitoring. To be effective for Antarctic biosecurity, eDNA tests must have appropriate sensitivity and specificity to distinguish non-native from native Antarctic species, and be fit-for-purpose. This requires knowledge of the priority risk species or taxonomic groups for which eDNA surveillance will be informative, validated eDNA assays for those species or groups, and reference DNA sequences for both target non-native and related native Antarctic species. Here, we used an expert elicitation process and decision-by-consensus approach to identify and assess priority biosecurity risks for the Australian Antarctic Program (AAP) in East Antarctica, including identifying high priority non-native species and their potential transport pathways. We determined that the priority targets for biosecurity monitoring were not individual species, but rather broader taxonomic groups such as mussels (Mytilus species), tunicates (Ascidiacea), springtails (Collembola), and grasses (Poaceae). These groups each include multiple species with high risks of introduction to and/or establishment in Antarctica. The most appropriate eDNA methods for the AAP must be capable of detecting a range of species within these high-risk groups (e.g., eDNA metabarcoding). We conclude that the most beneficial Antarctic eDNA biosecurity applications include surveillance of marine species in nearshore environments, terrestrial invertebrates, and biofouling species on vessels visiting Antarctica. An urgent need exists to identify suitable genetic markers for detecting priority species groups, establish baseline terrestrial and marine biodiversity for Antarctic stations, and develop eDNA sampling methods for detecting biofouling organisms. This work was supported as a Science Innovation Project by the Department of Agriculture, Water and the Environment’s Science Innovation Program funding 2021–22 (project team: A.J.M., L.J.C., D.M.B., C.K.K., J.S.S. and L.S.). Support was also provided (to J.D.S, E.L.J., S.A.R., J.S.S., M.I.S., J.M.S., N.G.W.) from Australian Research Council SRIEAS grant SR200100005. P.C. and K.A.H. are supported by NERC core funding to the BAS Biodiversity, Evolution and Adaptation Team and Environment Office, respectively. L.R.P. and M.G. are supported by Biodiversa ASICS funding.

Published
2023

41. The authors' reply

Author

Dafforn, Katherine A, Glasby, Tim M, Airoldi, Laura, Rivero, Natalie K, Pinto, Mariana Mayer, and Johnston, Emma L

Published
2015

46. The Role of Propagule Pressure in Invasion Success

Author

Johnston, Emma L., Piola, Richard F., Clark, Graeme F., Caldwell, M. M., editor, Heldmaier, G., editor, Jackson, R. B., editor, Lange, O. L., editor, Mooney, H. A., editor, Schulze, E. -D., editor, Sommer, U., editor, Rilov, Gil, editor, and Crooks, Jeffrey A., editor

Published
2009
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