The economic costs of cystic echinococcosis (CE) in Jordan, a developing country of lower-middle income, were investigated. Initial cost-estimates for livestock were based on the published prevalences of Echinococcus granulosus infection in sheep and goats and the values of livestock-related products together with likely production losses. Likewise, the annual numbers of human cases of CE were estimated using published surgical incidences in man. The costs of surgery were estimated from hospital records and by costing out the procedures each patient received whilst undergoing treatment. After comparing the quality of life of patients treated for CE with that of case-matched controls, it appeared that the treated patients had some long-term morbidity caused either by the disease or the resulting treatment. A simple spreadsheet model was built up, to sum the individual cost items. Each cost item and each of the data related to prevalence and incidence was assigned a mathematical distribution and varied randomly, using Monte-Carlo techniques, throughout its range, over 10 000 simulations. The results of the study indicate that the most likely range of annual economic losses attributable to CE in Jordan (encompassing 95% confidence limits) is from U.S.$2 602 215-6533 661, with a median of U.S.$3 874 070.

Some of the important environmental and plant factors influencing the germination and early seedling development of a number of temperate grasses and legumes have been investigated under controlled conditions. Significant differences were found between legumes and grasses in a number of characters which appear to be important for establishment under field conditions, including quantitative aspects of water absorption, rates of germination, and early root elongation. Ryegrass was superior to all other species in its ability to germinate under conditions of moisture stress. The lower limit for germination was from 4 to 6 bars below the limiting potential found for the other species, and thus may be one of the important factors contributing to the ease of establishment of this species in the field. The early onset of autotrophic growth in young seedlings, as judged by the utilization of external nutrients and the attainment of positive net photosynthesis, occurs within 5 days of imbibition under favourable conditions, well before the exhaustion of endogenous reserves. This highlights the need for adequate water, nutrients, and light during this early stage of seedling development. It also suggests that reserves available to the seedling are probably in excess of requirements under favourable conditions, and may be of potential value under adverse conditions. These results are discussed in relation to the definition of field problems, and to some likely breeding objectives to improve establishment.

Some of the factors influencing the establishment and survival of temperate pasture species when sown on the soil surface were investigated. The following were the main findings from experiments conducted in the field and in a controlled environment. (1) Both the establishment and survival of seedlings sown by broadcasting on to non-arable land can be significantly improved by a prior treatment of the site with herbicide to reduce competition from existing vegetation. (2) Providing protection for seeds by retaining dead vegetative cover, or by creating some form of surface roughness, improves establishment as it reduces desiccation and provides a more favourable moisture environment in the vicinity of the seed. (3) Uptake of water by seeds resting on the soil surface is enhanced by absorbent lime or bentonite coatings, and increased germination results. (4) Failure of radicles to penetrate the soil following germination is an important factor limiting the establishment of legumes on exposed sites, and any restraint on the movement of germinating seeds under these conditions improves the penetration of the radicle. (5) Variation between species in their ability to establish on the surface suggests that the choice of more suitable species, and selection to improve their adaptation in this respect, could also contribute a great deal to the efficiency of aerial seeding.

The dynamics of an annual pasture community are described from a ¢ve-year experimental and monitoring study. The community was dominated by two grasses (Lolium rigidum and Vulpia bromoides) and a legume (Trifolium subterraneum). Fits of population dynamic models to per capita rates of population change indicate that interactions between the grasses were generally strong, while interactions between the grasses and legumes were weaker. Most, but not all, of the net e¡ects of competition on population growth could be attributed to interactions occurring during plant growth. Phase-plane analysis indicated that, for a constant environment, a joint equilibrium of the two grasses is unstable since interspeci¢c competition between Lolium and Vulpia is stronger than intraspeci¢c competition. Consequently, the community will tend to a mixture of only one or other of the grass species and T. subterraneum, depending on the founding composition of the pasture. Analysis of data taken from a year in which a drought occurred (1993^1994) demonstrated profound e¡ects on all three species. Modelling of the long-term impacts of the e¡ects of repeated droughts showed that disturbance of this form overrides the founder e¡ect observed under constant conditions. Consequently, Vulpia is ultimately able to invade any mixture of the other species in environments where stochastic disturbances occur.

Grazing management strategies to alter botanical composition of native pastures were investigated at 4 locations in the high rainfall zone of south-east Australia, including Tasmania. These studies were conducted as part of the Temperate Pasture Sustainability Key Program, which evaluated the effects of grazing management on a wide range of pasture types between 1993 and 1996. Pastures in this study were based on Aristida ramosa/Bothriochloa macra, Microlaena stipoides–Austrodanthonia spp. or Themeda triandra–Austrodanthonia spp. Seasonal rests, increased grazing pressure in spring, mob stocking and cutting for hay were compared to continuous grazing at all sites. In addition, specific local treatments were tested at individual sites. Changes in composition resulting from the treatments were minimal at most sites. This may have been due to a combination of the inherent stability of the pastures, the relatively short duration of the experiments, and the drought conditions experienced, which minimised differences between treatments. Some strategies to alter composition of natural pastures are suggested. In the Aristida–Bothriochloa pasture there was a general decrease in Aristida and an increase in Bothriochloa, which was largely unaffected by the type of grazing management applied. The combination of drought conditions and increasing grazing pressure was sufficient to alter composition without specific management strategies being necessary. In the Themeda–Austrodanthonia pasture, resting in spring, 12-month rests or cutting for hay (which involved a spring rest) allowed Themeda to increase in the pasture. The Microlaena–Austrodanthonia pastures were very stable, especially where annual grass content was low. However, certain treatments allowed Microlaena to increase, a result which is regarded as being favourable. The major effects in these latter pastures were on undesirable species. Vulpia spp. were reduced by resting in autumn and increased spring grazing pressure, while Holcus lanatus was increased dramatically by resting in spring and was also increased by resting in autumn or winter, but only when conditions were suitable for growth of this species. In many cases, treatment differences were only expressed following recovery from drought, showing that timing of grazing management to achieve change is critical.