New screening test to predict the potential impact of ivermectin-contaminated cattle dung on dung beetles

According to European Union recommendations, a test method has been developed to evaluate the effects of veterinary pharmaceuticals on dung feeding insects. This test method was evaluated with the dung beetle Aphodius constans by using fecal residues of ivermectin after a pour-on administration. Dung of different age (and thus containing different concentrations of ivermectin) as well as mixtures of highly-contaminated spiked dung with untreated control dung were studied in five test runs in two laboratories. The concentration of ivermectin (active substance; a.s.) in the dung samples was verified analytically. The main test endpoint was the survival of first instar larvae. The LC50 using dung directly obtained from treated cattle ranged from 470 to 692 microg a.s. kg(-1) dung (dry weight; d.w.) and 67 to 97 microg a.s. kg(-1) dung (fresh weight; f.w.). Using mixtures, the outcome of two tests was almost identical: 770 to 781 microg a.s. kg(-1) dung (d.w.); 109 to 132 microg a.s. kg(-1) dung (f.w.). In comparison to the LC50 values obtained when ivermectin was spiked in control dung at several concentrations (LC50 880-985 microg a.s. kg(-1) dung (d.w.)), the LC50 values were again very similar. Three conclusions can be drawn from these results. The proposed test method seems to be robust and allows for the initiation of an international validation process (including ringtesting). Because of only small differences found in tests in which the test substance was spiked into control dung and those in which dung from treated cattle was applied, the use of a standard test method is proposed. The effects of ivermectin on ecologically relevant dung beetles obtained in a standardised test method reflect the results from field studies and are in the range of environmentally relevant concentrations.     

Exotic tree species displace indigenous ones on farms at intermediate altitudes around Mount Kenya

Agroforestry systems are potentially suitable for conservation of tree genetic resources. Farmers around Mt. Kenya usually integrate trees into their farm. Large parts of these trees seem to be of exotic origin, whereas indigenous species have priority for conservation. This study aimed at determining on-farm richness, composition and frequency of indigenous and exotic woody species around Mount Kenya to assess the suitability of farms for the conservation of indigenous tree species. 265 on-farm plots of 0.5 ha size each were selected in 18 different agro-ecological zones by using a stratified sampling scheme. All woody species within the plot were recorded with their local and scientific names. Total species richness was 424 (including 306 indigenous ones), mean richness per plot 16.5 species (including 8.8 indigenous ones). Eight out of the 10 most frequent species were exotic ones with Grevillea robusta from Australia ranking first (found on almost 76% of the surveyed farms). The proportion of indigenous species increased with increasing aridity and temperature. Dominance of exotic species was found at farms of humid mid- and highlands. Ordination analysis revealed that mostly exotic species contributed to separation of farms in the highlands and upper midlands, whereas indigenous species in the lower midlands and lowlands. As the frequencies of most indigenous trees were low, only parts of the surveyed farms can contribute to conservation of tree genetic resources, particularly the less intensively managed farms of the more arid lands. Farmers’ access to knowledge on valuable indigenous tree species and to quality seedlings of these trees need to be improved to increase indigenous species’ frequencies on farms and possibly to replace some of the exotic species in the future.     

A protocol for analysing the costs and benefits of phytosanitary measures*

This paper describes a protocol developed within the PRATIQUE project for applying cost/benefit analysis to select appropriate phytosanitary measures for use against quarantine pests. The protocol consists of nine steps, each underpinned by clear guidelines for collating and structuring the relevant data, to assist risk managers with the challenging task of assessing the benefits and costs of phytosanitary measures in a consistent, transparent and reproducible manner. Together with the decision‐support scheme that generates contingency plants and prioritizes action during pest outbreaks, it provides a framework for decision making on phytosanitary measures and helps to provide economic justification for selecting appropriate measures. The practical application of the protocol is demonstrated using two examples: cost/benefit analysis of eradication measures against Anoplophora glabripennis in Northern Italy; and eradication and containment measures against Diabrotica virgifera virgifera in Germany.     

Plant species richness and diversity in urban and peri-urban gardens of Niamey,Niger

Urban and peri-urban agriculture (UPA) significantly contributes to food and nutritional security of urban dwellers in many African countries. Economic and demographic pressures often lead to transformation of subsistence-oriented traditional homegardens into commercial production units. Such transformation is claimed to result in decreasing plant diversity, particularly of local species. A study was therefore undertaken in 51 gardens of Niamey, Niger, to assess the factors determining plant diversity and the suitability of UPA for in situ conservation of plant genetic resources. In each garden, the number and abundance of all human-used plant species were determined, and species density, Shannon index and Shannon evenness were calculated. In the 51 surveyed gardens, a total of 116 plant species were cultivated, most of them for the production of fruits or vegetables. Annual vegetables dominated, particularly exotic species grown for sale. In the cold season, an average of 14 species were cultivated per garden, the Shannon index was 0.96 and evenness was 0.39. Commercial gardens had a species richness similar to that of subsistence gardens, but a lower evenness (P < 0.005), caused by the dominance of a few vegetable species. Gardens of immigrants had a lower Shannon index than those of members of the local Djerma ethnic group. Stepwise multiple regression analysis showed significant influence of various variables on plant species richness and diversity parameters: garden size (richness and Shannon index), ethnicity of the gardener (richness and evenness), gender of the gardener and cash-oriented production (evenness), household size (richness) and garden possession status (Shannon index). Cluster analysis revealed the existence of five garden types. The highest species richness and diversity, particularly of perennial and local species, was found in large, peri-urban, commercial gardens managed by relatively wealthy, elderly gardeners with large families and a regular non-agricultural income.     

Crop diversity in homegardens of southwest Uganda and its importance for rural livelihoods

Homegardens are traditional food systems that have been adapted over generations to fit local cultural and ecological conditions. They provide a year-round diversity of nutritious foods for smallholder farming communities in many regions of the tropics and subtropics. In southwestern Uganda, homegardens are the primary source of food, providing a diverse diet for rural marginalized poor. However, national agricultural development plans as well as economic and social pressures threaten the functioning of these homegardens. The implications of these threats are difficult to evaluate, because the structure and functions of the homegardens are not well understood. The aim of the study was to identify patterns and influencing factors in the diversity of homegardens by documenting the floristic diversity and its interactions with spatial, environmental and socio-economic factors. A geographically and socially focused assessment of floristic diversity in 102 randomly selected homegardens in three districts of southwest Uganda was conducted along a deforestation gradient following a human ecology conceptual framework and testing multiple quantitative hypotheses regarding the above mentioned factors. A merged mixed-method approach was followed to provide context and feedback regarding quantitative findings. Results show a high total richness of 209 (mean 26.8 per homegarden) crop species (excluding weeds and ornamentals) dominated by food species, which constituted 96 percent of individuals and 44 percent of all species. Forest-edge homegardens maintained higher plant diversity compared to homegardens in deforested areas and near degraded wetlands. Multiple linear regression models indicated elevation, location, homegarden size, distance to market, additional land ownership (outside the homegarden) and livestock ownership as significant predictors of crop diversity. Cluster analysis of species densities revealed four garden types: ‘diverse tree gardens’, ‘small forest-edge gardens’, ‘large, old, species-rich gardens’, and ‘large, annual-dominated herb gardens’, with 98% correct classification. Location, elevation, and garden size were also important determinants in the cluster assignment. We conclude that the diversity of the studied homegardens may be changing as part of adaptive traditional practices and in response to external drivers. The identified patterns illustrate the importance of homegardens for rural livelihoods and may offer some ways to support farmers to maintain these systems as relevant mechanisms for development in Uganda.     

Modelling and mapping spread in pest risk analysis: a generic approach*

Assessing the likelihood and magnitude of spread is one of the cornerstones of pest risk analysis (PRA), and is usually based on qualitative expert judgment. This paper proposes a suite of simple ecological models to support risk assessors who also wish to estimate the rate and extent of spread, e.g. when modelling the dynamics of invasion and the economic impacts that may result. Models are based on simple ecological principles, such as logistic growth, radial range expansion and population growth in combination with dispersal. Different models capture different perspectives of the spread process, being based on pest density or simply presence/absence, and they compare spatially explicit and spatially implicit approaches. A case study on Diabrotica virgifera virgifera is provided for illustration. The suite of models requires further development and testing with the risk assessment community building familiarity before their more general application in PRA.     

Effects of transformation processes on plant species richness and diversity in homegardens of the Nuba Mountains,Sudan

Traditional homegardens (HGs) are considered to harbor high levels of plant diversity and have been therefore characterized as sustainable agro-ecosystems suitable for on-farm (incl. circa situm) conservation of plant genetic resources. While the functional structure of traditional HGs is poorly understood specifically for semi-arid and arid regions, their plant species richness and diversity is increasingly threatened by recent and fast evolving agricultural transformation processes. This has been particularly claimed for traditional jubraka HG systems of Sudan. Therefore, sixty-one HGs in four villages of the Nuba Mountains, South-Kordofan Province, Sudan, were randomly selected, geographically recorded and plant richness and abundance determined and plant diversity parameters calculated. In addition, socio-economic household data were assessed by interviews and soil samples taken to allow a comprehensive analysis of putative factors affecting HG plant diversity across different villages, levels of commercialization and plant species composition based clusters. A total of 110 species from 35 plant families were grown in the HGs along with 71 ornamentals. Perennial species accounted for 57 % including 12 indigenous fruit tree (IFT) species and six exotic fruit tree species. Mean species richness of useful plant species (excluding ornamentals) per HG was 23 (range 6–46). On average, 41 % of the 23 species per HG were of exotic origin, however, with a large range (21–83 %) among locations. Mean diversity and evenness indices were 1.46 (range 0.49–2.42) and 0.48 (0.15–0.87), respectively. The level of commercialization of HGs only marginally affected species diversity measures although the species richness was significantly higher for commercial than subsistence HGs. Species richness was higher on lower (6.6–7.2) pH soils. IFT richness was highly variable, but non-significantly different across the four locations. Plant species richness and diversity was high in comparison with other HG systems in semi-arid regions. Cluster analysis was found to be a valuable tool to classify HGs and to extract homogeneous HG types with low, intermediate and high richness and diversity. In addition, the share of exotic and ornamental species in HGs indicated a trend towards the loss of traditional farming practices, particularly in areas with good market access. The data did not indicate the hypothesized loss of inter-specific diversity due to commercialization and species richness was numerically even higher for market-oriented HGs compared to subsistence ones.     

Der Baobab (Adansonia digitata L.): Wildobst aus Afrika für Deutschland und Europa?!

In Germany and Europe exotic fruits from distant places are becoming more and more important. In the tropics and subtropics an enormous variety of edible fruits exists. In 2008 the dry fruit pulp of the baobab (Adansonia digitata L.) was approved as novel food for the EU and thus entered the formal food market. Hence, an increasing number of products became available in Europe. The baobab is an impressive tree in the savannas of Africa. Due to its dense and wide spreading root system and its enormous water storing capacity in the stem, the tree can grow under very dry environmental conditions. In many regions of Africa it is a multipurpose indigenous fruit tree species which offers shelter and provides food, fodder and medicine as well as raw material for many purposes. However, even in Europe a wide range of products is now available as shown in the present study, which identified more than 300 baobab products or products with baobab as an ingredient. In Germany, not only the natural baobab pulp but also ready-made foodstuffs such as soft drinks, sandwich spreads, cereal bars, sweets and chocolates are available. Furthermore, a diverse range of pharmaceutical and cosmetic products with extracts from the baobab is available in the market. The products range from after shave and perfume to shampoo and shower gel to leg lotion and foot spray. In Germany baobab saplings and seeds are offered for planting and cultivation as an indoor pot plant. Commercially marketed baobab bonsai seedlings for the European market are produced in Senegal. In Africa the baobab fruits are mainly harvested from wild stands. However, the commercial production of baobab fruits in orchards could be an important future opportunity for income generation to many local households. More research on baobab, including the domestication of this wild fruit tree species, and the conservation of its natural stands as important genetic resource are prerequisites for sustainably increased fruit production.     

NEPTUN,PAPA, Vergleichs- und Demonstrationsbetriebe oder Wer hat da noch den Durchblick?

The Institute for Strategies and Technology Assessment of the Julius Kühn-Institute operates four different networks: demonstration farms on IPM, reference farms for plant protection, panel pesticide applications and NEPTUN farms. All networks deal with the use of plant protection products in agricultural practice. The latter three also have very similar tasks and are closely interlinked. As a result, outsiders have significant problems distinguishing between those four farm networks and assigning the respective activities to the “right” corresponding network.Therefore, the publication aims at presenting comparatively the tasks and objectives of the various networks and to explain to the reader what are they doing, what are the differences, as well as why and how the establishment of these four different farm networks has come about.