Risk assessment, eradication, and biological control: global efforts to limit Australian acacia invasions

Aim? Many Australian Acacia species have been planted around the world, some are highly valued, some are invasive, and some are both highly valued and invasive. We review global efforts to minimize the risk and limit the impact of invasions in this widely used plant group. Location? Global. Methods? Using information from literature sources, knowledge and experience of the authors, and the responses from a questionnaire sent to experts around the world, we reviewed: (1) a generalized life cycle of Australian acacias and how to control each life stage, (2) different management approaches and (3) what is required to help limit or prevent invasions. Results? Relatively few Australian acacias have been introduced in large numbers, but all species with a long and extensive history of planting have become invasive somewhere. Australian acacias, as a group, have a high risk of becoming invasive and causing significant impacts as determined by existing assessment schemes. Moreover, in most situations, long-lived seed banks mean it is very difficult to control established infestations. Control has focused almost exclusively on widespread invaders, and eradication has rarely been attempted. Classical biological control is being used in South Africa with increasing success. Main conclusions? A greater emphasis on pro-active rather than reactive management is required given the difficulties managing established invasions of Australian acacias. Adverse effects of proposed new introductions can be minimized by conducting detailed risk assessments in advance, planning for on-going monitoring and management, and ensuring resources are in place for long-term mitigation. Benign alternatives (e.g. sterile hybrids) could be developed to replace existing utilized taxa. Eradication should be set as a management goal more often to reduce the invasion debt. Introducing classical biological control agents that have a successful track-record in South Africa to other regions and identifying new agents (notably vegetative feeders) can help mitigate existing widespread invasions. Trans-boundary sharing of information will assist efforts to limit future invasions, in particular, management strategies need to be better evaluated, monitored, published and publicised so that global best-practice procedures can be developed. (Résumé d'auteur

The effect of learning on feedback-related potentials in adolescents with dyslexia: an EEG-ERP study.

INTRODUCTION: Individuals with dyslexia exhibit associated learning deficits and impaired executive functions. The Wisconsin Card Sorting Test (WCST) is a learning-based task that relies heavily on executive functioning, in particular, attention shift and working memory. Performance during early and late phases of a series within the task represents learning and implementation of a newly learned rule. Here, we aimed to examine two event-related potentials associated with learning, feedback-related negativity (FRN)-P300 complex, in individuals with dyslexia performing the WCST. METHODS: Adolescents with dyslexia and age-matched typical readers performed the Madrid card sorting test (MCST), a computerized version of the WCST. Task performance, reading measures, and cognitive measures were collected. FRN and the P300 complex were acquired using the event-related potentials methodology and were compared in early vs late errors within a series. RESULTS: While performing the MCST, both groups showed a significant reduction in average reaction times and a trend toward decreased error rates. Typical readers performed consistently better than individuals with dyslexia. FRN amplitudes in early phases were significantly smaller in dyslexic readers, but were essentially equivalent to typical readers in the late phase. P300 amplitudes were initially smaller among readers with dyslexia and tended to decrease further in late phases. Differences in FRN amplitudes for early vs late phases were positively correlated with those of P300 amplitudes in the entire sample. CONCLUSION: Individuals with dyslexia demonstrate a behavioral and electrophysiological change within single series of the MCST. However, learning patterns seem to differ between individuals with dyslexia and typical readers. We attribute these differences to the lower baseline performance of individuals with dyslexia. We suggest that these changes represent a fast compensatory mechanism, demonstrating the importance of learning strategies on reading among individuals with dyslexia

A comparison of individuals with dyslexia and typical readers on cognitive measures (M = mean, SD = standard deviation).

<p>*<i>P</i><.05;</p><p>**<i>P</i><.01;</p><p>***<i>P</i><.001, ns =  nonsignificant.</p

Behavioral measures administered to all participants.

<p>Behavioral measures administered to all participants.</p

FRN and P300 cue-locked Event-related components.

<p>Elicitation of ERPs following cue presentation for individuals with dyslexia (right column) and typical readers (left column). Upper rows: frontal region (Fz electrode); middle rows: fronto-central regions (FCz electrode) bottom rows: central regions (Cz electrode). Smooth line: “early phase”; dashed line: “late phase.” FRN was identified as the most negative peak at 100–250 msec and P300 as the most positive peak at 250–400 msec. X axis: time in msec; Y axis: amplitude in µV. Note that the negative axis is plotted down.</p

Amplitudes (in µV) of FRN and P300 cue-locked components for individuals with dyslexia and typical readers for early and late errors conditions.

<p>*<i>P</i><.05;</p><p>**<i>P</i><.01, ns =  nonsignificant.</p

A comparison of individuals with dyslexia and typical readers in terms of accuracy (error rates) and reaction times in the Madrid card-sorting test.

<p>*<i>P</i><.05.</p

MCST task design and time windows for analysis (modeled after Barcelo, [38]).

<p>The data used for the current study's analysis were “cue-locked” only.</p

Correlations of ERPs and cognitive abilities with reading measures.

<p>*<i>P</i><.05;</p><p>**<i>P</i><.01;</p><p>***<i>P</i><.001. Data were corrected for multiple comparisons.</p

An illustration of the EEG data-analyses.

<p>An illustration of the EEG data-analyses.</p