Australian Acacia are invasive in many parts of the world. Despite significant mechanical and biological efforts to control their invasion and spread, soil-stored seed banks prevent their effective and sustained removal. In response South Africa has had a strong focus on employing seed reducing biological control agents to deal with Australian Acacia invasion, a programme that is considered as being successful. To provide a predictive understanding for their management, seed banks of four invasive Australian acacia species (Acacia longifolia, A. mearnsii, A. pycnantha and A. saligna) were studied in the Western Cape of South Africa. Across six to seven sites for each species, seed bank sizes were estimated from dense, monospecific stands by collecting 30 litter and soil samples. Average estimated seed bank size was large (1017 to 17261 seed m-2) as was annual input into the seed bank, suggesting that these seed banks are not residual but are replenished in size annually. A clear relationship between seed bank size and stem diameter was established indicating that mechanical clearing should be conducted shortly after fire-stimulated recruitment events or within old populations when seed banks are small. In dense, monospecific stands seed-feeding biological control agents are not effective in reducing seed bank size.

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<p><strong>Objectives.</strong> Anxiety disorders are the most common childhood psychiatric disorders. Previous research suggests that South African rates may be high. Our study examined the prevalence and severity of anxiety and depression among Grade 11 and 12 learners attending schools in central Bloemfontein. Learners’ perception of the important stressors as well as the most relevant coping strategies were investigated.<strong></strong></p><p><strong> Methods.</strong> A cross-sectional study was conducted by using self-assessment rating scales and questionnaires. The Hospital Anxiety and Depression Scale (HADS) was used to screen for anxiety and depressive symptoms. Participants were provided with an additional list of possible stressors and coping skills, from which they identified those applicable to themselves. All students enrolled in Grades 11 and 12 at the selected schools during August 2009 were eligible for inclusion.</p><p><strong>Results.</strong> Five hundred and fifteen learners participated in the study, of whom 32.0% presented with moderate or severe anxiety and 5.3% with moderate or severe depressive symptoms. Mild symptoms were reported by an additional 29.0% on the anxiety subscale and 14% on the depression subscale of the HADS. Academic workload was reported as the main source of stress (81.4%).</p><p><strong>Conclusions.</strong> Although the study has limitations in terms of methodology and size, resulting in undetermined validity, it indicates possible higher prevalence rates for anxiety and depression than in previous South African studies and worldwide prevalence rates for adolescents. Pupils were generally hesitant to seek help from formal assistance structures provided by the schools, and preferred discussing problems with parents or friends.</p>