Plastic pollution in Antarctica and the Southern Ocean has been recorded in scientific literature since the 1980s; however, the presence of microplastic particles (<5 mm) is less understood. Here, we ...aimed to determine whether microplastic accumulation would vary among Antarctic and Southern Ocean regions through studying 30 deep-sea sediment cores. Additionally, we aimed to highlight whether microplastic accumulation was related to sample depth or the sediment characteristics within each core. Sediment cores were digested and separated using a high-density sodium polytungstate solution (SPT) and microplastic particles were identified using micro-Fourier-transform infrared spectroscopy (μFTIR). Microplastic pollution was found in 93% of the sediment cores (28/30). The mean (±SE) microplastics per gram of sediment was 1.30 ± 0.51, 1.09 ± 0.22, and 1.04 ± 0.39 MP/g, for the Antarctic Peninsula, South Sandwich Islands, and South Georgia, respectively. Microplastic fragment accumulation correlated significantly with the percentage of clay within cores, suggesting that microplastics have similar dispersion behavior to low density sediments. Although no difference in microplastic abundance was found among regions, the values were much higher in comparison to less remote ecosystems, suggesting that the Antarctic and Southern Ocean deep-sea accumulates higher numbers of microplastic pollution than previously expected.
Defining the Impact of Non‐Native Species JESCHKE, JONATHAN M; BACHER, SVEN; BLACKBURN, TIM M ...
Conservation biology,
October 2014, Letnik:
28, Številka:
5
Journal Article
Recenzirano
Odprti dostop
Non‐native species cause changes in the ecosystems to which they are introduced. These changes, or some of them, are usually termed impacts; they can be manifold and potentially damaging to ...ecosystems and biodiversity. However, the impacts of most non‐native species are poorly understood, and a synthesis of available information is being hindered because authors often do not clearly define impact. We argue that explicitly defining the impact of non‐native species will promote progress toward a better understanding of the implications of changes to biodiversity and ecosystems caused by non‐native species; help disentangle which aspects of scientific debates about non‐native species are due to disparate definitions and which represent true scientific discord; and improve communication between scientists from different research disciplines and between scientists, managers, and policy makers. For these reasons and based on examples from the literature, we devised seven key questions that fall into 4 categories: directionality, classification and measurement, ecological or socio‐economic changes, and scale. These questions should help in formulating clear and practical definitions of impact to suit specific scientific, stakeholder, or legislative contexts.
Disease emergence and invasions Hatcher, Melanie J.; Dick, Jaimie T. A.; Dunn, Alison M.
Functional ecology,
December 2012, Letnik:
26, Številka:
6
Journal Article
Recenzirano
Odprti dostop
1. Emerging infectious diseases (EIDs) are recognized as having significant social, economic and ecological costs, threatening human health, food security, wildlife conservation and biodiversity. We ...review the processes underlying the emergence of infectious disease, focusing on the similarities and differences between conceptual models of disease emergence and biological invasions in general. 2. Study of the IUCN's list of the world's worst invaders reveals that disease is cited as a driver behind the conservation, medical or economic impact of nearly a quarter of the species on the data base. 3. The emergence of novel diseases in new host species are, in essence, examples of invasions by parasites. Many of the ecological and anthropogenic drivers of disease emergence and classical invasions are also shared, with environmental change and global transport providing opportunities for the introduction and spread of invaders and novel parasites. 4. The phases of disease emergence and biological invasions have many parallels; particularly the early and late phases, where demographic and anthropogenic factors are key drivers. However, there are also differences in the intermediate phases, where host—parasite co-evolution plays a crucial role in determining parasite establishment in novel hosts. 5. Similar opportunities and constraints on control and management occur at the different phases of invasions and disease emergence. However, exploitation of host immune responses offers additional control opportunities through contact control and vaccination against EIDs. We propose that cross-fertilization between the disciplines of disease emergence and invasion biology may provide further insights into their prediction, control and management.
Invasion ecology urgently requires predictive methodologies that can forecast the ecological impacts of existing, emerging and potential invasive species. We argue that many ecologically damaging ...invaders are characterised by their more efficient use of resources. Consequently, comparison of the classical ‘functional response’ (relationship between resource use and availability) between invasive and trophically analogous native species may allow prediction of invader ecological impact. We review the utility of species trait comparisons and the history and context of the use of functional responses in invasion ecology, then present our framework for the use of comparative functional responses. We show that functional response analyses, by describing the resource use of species over a range of resource availabilities, avoids many pitfalls of ‘snapshot’ assessments of resource use. Our framework demonstrates how comparisons of invader and native functional responses, within and between Type II and III functional responses, allow testing of the likely population-level outcomes of invasions for affected species. Furthermore, we describe how recent studies support the predictive capacity of this method; for example, the invasive ‘bloody red shrimp’ Hemimysis anomala shows higher Type II functional responses than native mysids and this corroborates, and could have predicted, actual invader impacts in the field. The comparative functional response method can also be used to examine differences in the impact of two or more invaders, two or more populations of the same invader, and the abiotic (e.g. temperature) and biotic (e.g. parasitism) context-dependencies of invader impacts. Our framework may also address the previous lack of rigour in testing major hypotheses in invasion ecology, such as the ‘enemy release’ and ‘biotic resistance’ hypotheses, as our approach explicitly considers demographic consequences for impacted resources, such as native and invasive prey species. We also identify potential challenges in the application of comparative functional responses in invasion ecology. These include incorporation of numerical responses, multiple predator effects and trait-mediated indirect interactions, replacement versus non-replacement study designs and the inclusion of functional responses in risk assessment frameworks. In future, the generation of sufficient case studies for a meta-analysis could test the overall hypothesis that comparative functional responses can indeed predict invasive species impacts.
Ecological Impacts of Alien Species KUMSCHICK, SABRINA; GAERTNER, MIRIJAM; VILÀ, MONTSERRAT ...
Bioscience,
01/2015, Letnik:
65, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Despite intensive research during the past decade on the effects of alien species, invasion science still lacks the capacity to accurately predict the impacts of those species and, therefore, to ...provide timely advice to managers on where limited resources should be allocated. This capacity has been limited partly by the context-dependent nature of ecological impacts, research highly skewed toward certain taxa and habitat types, and the lack of standardized methods for detecting and quantifying impacts. We review different strategies, including specific experimental and observational approaches, for detecting and quantifying the ecological impacts of alien species. These include a four-way experimental plot design for comparing impact studies of different organisms. Furthermore, we identify hypothesis-driven parameters that should be measured at invaded sites to maximize insights into the nature of the impact. We also present strategies for recognizing high-impact species. Our recommendations provide a foundation for developing systematic quantitative measurements to allow comparisons of impacts across alien species, sites, and time.
Global determinants of prey naiveté to exotic predators Anton, Andrea; Geraldi, Nathan R.; Ricciardi, Anthony ...
Proceedings of the Royal Society. B, Biological sciences,
06/2020, Letnik:
287, Številka:
1928
Journal Article
Recenzirano
Odprti dostop
Prey naiveté—the failure of prey to recognize novel predators as threats—is thought to exacerbate the impact that exotic predators exert on prey populations. Prey naiveté varies under the influence ...of eco-evolutionary mediating factors, such as biogeographic isolation and prey adaptation, although an overall quantification of their influence is lacking. We conducted a global meta-analysis to test the effects of several hypothesized mediating factors on the expression of prey naiveté. Prey were overall naive towards exotic predators in marine and freshwater systems but not in terrestrial systems. Prey naiveté was most pronounced towards exotic predators that did not have native congeneric relatives in the recipient community. Time since introduction was relevant, as prey naiveté declined with the number of generations since introduction; on average, around 200 generations may be required to erode naiveté sufficiently for prey to display antipredator behaviour towards exotic predators. Given that exotic predators are a major cause of extinction, the global predictors and trends of prey naiveté presented here can inform efforts to meet conservation targets.
Understanding determinants of the invasiveness and ecological impacts of alien species is amongst the most sought-after and urgent research questions in ecology. Several studies have shown the value ...of comparing the functional responses (FRs) of alien and native predators towards native prey, however, the technique is under-explored with herbivorous alien species and as a predictor of invasiveness as distinct from ecological impact. Here, in China, we conducted a mesocosm experiment to compare the FRs among three herbivorous snail species: the golden apple snail, Pomacea canaliculata, a highly invasive and high impact alien listed in "100 of the World's Worst Invasive Alien Species"; Planorbarius corneus, a non-invasive, low impact alien; and the Chinese native snail, Bellamya aeruginosa, when feeding on four locally occurring plant species. Further, by using a numerical response equation, we modelled the population dynamics of the snail consumers. For standard FR parameters, we found that the invasive and damaging alien snail had the highest "attack rates" a, shortest "handling times" h and also the highest estimated maximum feeding rates, 1/hT, whereas the native species had the lowest attack rates, longest handling times and lowest maximum feeding rates. The non-invasive, low impact alien species had consistently intermediate FR parameters. The invasive alien species had higher population growth potential than the native snail species, whilst that of the non-invasive alien species was intermediate. Thus, while the comparative FR approach has been proposed as a reliable method for predicting the ecological impacts of invasive predators, our results further suggest that comparative FRs could extend to predict the invasiveness and ecological impacts of alien herbivores and should be explored in other taxa and trophic groups to determine the general utility of the approach.
Forecasting the ecological impacts of invasive species is a major challenge that has seen little progress, yet the development of robust predictive approaches is essential as new invasion threats ...continue to emerge. A common feature of ecologically damaging invaders is their ability to rapidly exploit and deplete resources. We thus hypothesized that the ‘functional response’ (the relationship between resource density and consumption rate) of such invasive species might be of consistently greater magnitude than those of taxonomically and/or trophically similar native species. Here, we derived functional responses of the predatory Ponto-Caspian freshwater ‘bloody red’ shrimp,
Hemimysis anomala
, a recent and ecologically damaging invader in Europe and N. America, in comparison to the local native analogues
Mysis salemaai
and
Mysis diluviana
in Ireland and Canada, respectively. This was conducted in a novel set of experiments involving multiple prey species in each geographic location and a prey species that occurs in both regions. The predatory functional responses of the invader were generally higher than those of the comparator native species and this difference was consistent across invaded regions. Moreover, those prey species characterized by the strongest and potentially de-stabilizing Type II functional responses in our laboratory experiments were the same prey species found to be most impacted by
H. anomala
in the field. The impact potential of
H. anomala
was further indicated when it exhibited similar or higher attack rates, consistently lower prey handling times and higher maximum feeding rates compared to those of the two
Mysis
species, formerly known as ‘
Mysis relicta
’, which itself has an extensive history of foodweb disruption in lakes to which it has been introduced. Comparative functional responses thus merit further exploration as a methodology for predicting severe community-level impacts of current and future invasive species and could be entered into risk assessment protocols.
In the Anthropocene, non-native freshwater fish introductions and translocations have occurred extensively worldwide. However, their global distribution patterns and the factors influencing their ...establishment remain poorly understood. We analyze a comprehensive database of 14953 freshwater fish species across 3119 river basins and identify global hotspots for exotic and translocated non-native fishes. We show that both types of non-native fishes are more likely to occur when closely related to native fishes. This finding is consistent across measures of phylogenetic relatedness, biogeographical realms, and highly invaded countries, even after accounting for the influence of native diversity. This contradicts Darwin's naturalization hypothesis, suggesting that the presence of close relatives more often signifies suitable habitats than intensified competition, predicting the establishment of non-native fish species. Our study provides a comprehensive assessment of global non-native freshwater fish patterns and their phylogenetic correlates, laying the groundwork for understanding and predicting future fish invasions in freshwater ecosystems.
Aquatic biosecurity remains a damp squib Coughlan, Neil E.; Cuthbert, Ross N.; Dick, Jaimie T. A.
Biodiversity and conservation,
08/2020, Letnik:
29, Številka:
9-10
Journal Article
PDF
