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Conservation managers are concerned about the impact that African elephants (Loxodonta africana) have on large tree species, necessitating the need for mitigation methods. Elephants actively avoid contact with African honeybees (Apis mellifera subsp. scutellata), staying clear of crop fields surrounded by beehive fence-lines and moving away from the sounds of swarming honeybees. Therefore, our objectives were to test whether the presence of beehives in trees influenced the likelihood of the tree receiving elephant impact, and compare these results to wire-netted (method used to prevent bark-stripping) and control (no treatment) trees. We selected a tree highly sought after by elephant, the marula tree (Sclerocarya birrea subsp. caffra), as our study species. We also assessed whether elephants avoided areas with marula trees containing beehives. Finally we provide a comparison of the financial costs of the beehive and wire-netting mitigation methods. We hung 50 active beehives in 50 trees, with 50 dummy beehives hung from branches on the opposite ends of each tree's main stem. We wire-netted another 50 trees and then assigned 50 trees as a control. Elephant impact on all 150 trees was measured prior to the addition of treatments and then post-treatment addition for 9 months. 54% of the control trees received some form of elephant impact, in comparison to 28% of the wire-netted trees and only 2% of the beehive trees. Wire-netting protected trees against bark-stripping but did not prevent elephants from breaking branches. Beehives proved to be the more effective mitigation method for elephant impact on large trees, although the presence of beehives did not prevent elephants from moving through the study site. The financial cost and maintenance required for the beehive mitigation method are greater than that of wire-netting, but the beehives can provide honey as an additive benefit on a small-scale usage level.

When flowers are harvested from wild plants an issue for conservation managers is whether sufficient seeds remain for population replacement, especially if it is subject to recurrent disturbance. Field data on the effect of flower picking on seed availability over 13 years were available for the most heavily exploited wildflower in Australia, Banksia hookeriana, a fire-killed shrub restricted to a 2000 km 2 area in the northern sandplains of southwestern Australia. These were combined with demographic data from 14 longterm monitoring plots scattered over the landscape. Growing conditions were termed 'good' to 'poor' depending on how they affected the number of inflorescences produced, and recruitment of young plants. A computer model was developed based on bestfit equations for all key processes accounting for seed and seedling production and loss. The model indicates that self-replacement (maintenance of a stable population size at a given age from one generation to the next) is unlikely for the first 5-11 years following fire, depending on growing conditions, even in the absence of picking. Picking has little effect on the minimum fire interval for self-replacement under good growing conditions, but, under poor conditions, minimum fire interval rises from 12 years at 0% picking to 20 years at 30% picking. Miscalculation of the intensity of picking allowable could have serious consequences for conservation of wild populations, as fires are most likely at 10-20 year intervals. A second computer model took inter-fire establishment into account. It gave similar results for self-replacement conditions, but also indicated that the level of picking that could be sustained diminishes sharply once fires occur at intervals > 20 years. We suggest caution be exercised by conservation authorities in setting the age to first picking and the levels of picking permitted for wild populations of Banksia hookeriana. Our models are suitable for a wide range of vulnerable, fire-killed species at present harvested from the wild.

This paper describes a population viability analysis (PVA) for Euphorbia clivicola R.A. Dyer, a threatened succulent confined to only two known populations in the Northern Province of South Africa, one of which is protected in a nature reserve. The PVA explicitly compared the relative effectiveness of four management scenarios in bringing about the recovery of the protected population that had shown a 91% decline over the decade during which the population was monitored. Demographic monitoring data as well as autecological data collected in 1996 were used to determine the temporal variation in observed demographic and reproductive parameters. The model parameters were allowed to vary randomly over the observed ranges in order to incorporate stochasticity of the environmental factors fire, herbivory and rainfall. If future management practices remain unchanged, the model predicted that there is an 88% probability of the protected population becoming extinct within the next 20 years. The population should recover under a management scenario involving a fire frequency of every 3 years, the exclusion of herbivores and augmentation. The model has since been validated with data collected in 1999. Such analyses are useful for adaptive management purposes.

A stage-based model was developed for the population dynamics of Banksia goodii , a rare long-lived shrub in Western Australia. While few seeds are produced, death of adults due to senescence or fire has yet to be observed. A sensitivity analysis showed that population growth is close to zero as long as post-fire mortality and recruitment are within their usual low bounds. To remain viable, the size of a population remnant should exceed about 80 individuals. If fires occur at random intervals, an average of one fire in 10–15 years is optimal. Regular fires should have inter-fire periods of 15–20 years. Loss of adult plants due to human activities, such as land clearing, will increase mortality beyond its natural bounds and cannot be compensated for, due to the low fecundity of this species. Hand sowing after a fire may raise establishment by orders of magnitude and achieve a permanent population increase within the first year. Conservation authorities should target the sensitive factors through active management at the recruitment stage and by ensuring that no further loss of mature plants takes place through land clearance. ©