Suchergebnisse

The 8th European Vertebrate Pest Management Conference was held 26-30 September 2011 in Berlin, Germany. It was organised by the Vertebrate Research Group of Julius Kühn Institute, Federal Research Centre for Cultivated Plants and the Faculty of Agriculture and Horticulture of Humboldt University. The Conference is a biennial meeting of people interested in various aspects of vertebrate pest management. Overabundant vertebrate populations can be responsible for crop loss, public and animal health concerns, structural damage and confl icts with conservation interests. The conference is a forum for all involved in basic research in vertebrate biology, ecology, methodology, legislation and the application of these topics in wildlife management.The intention of the meeting was to foster the interaction of experts from Europe and beyond specializing in diff erent fi elds of applied and basic vertebrate research because thorough knowledge of all relevant aspects is a vital prerequisite to make informed decisions in vertebrate pest management. This book of abstracts summarizes all contributions that were presented in 9 symposia: 1) Fertility control in vertebrates, 2) Invasive vertebrates, 3) Management of birds, 4) New tools and methods - alternatives to anticoagulants including a workshop, 5) Population dynamics and management of mammals, 6) Rodenticide resistance and management of commensal rodents, 7) Vertebrate management in developing/emerging countries, 8) Wild boar biology and management, and 9) Zoonotic diseases in vertebrates.

The murine cytomegalovirus (MCMV) may be used as a vector for fertility control in house mice, which are a significant agricultural pest in south-eastern Australia. The transmission of MCMV can be density dependent and is mostly subclinical in its effect on mice; however, little is known about which individual parameters influence whether an animal is likely to be infected or not.We examined the impact of age and reproductive history on seroprevalence of MCMV in house mice during the breeding season. MCMV seroprevalence was density dependent and there was a linear increase in seroprevalence with increasing age, starting at 25% for 1-month-old mice and 100% for all individuals older than five months. There was no clear indication that the number of previous pregnancies was related to MCMV seroprevalence.The high prevalence of MCMV among adult female house mice (84%) implies that an Australian field strain of MCMV could be a promising vector for an immunocontraceptive for house mice.

Ricefield rats (Rattus argentiventer) in south-east Asian rice fields and house mice (Mus domesticus) in Australian grain fields are major pest species. They cause damage before and after harvest and carry zoonotic diseases. For both species, management techniques have been pursued using the approach of immunocontraceptive vaccination. We review results from a series of enclosure and field studies conducted with these species to assess the effects of fertility control in small rodents. In the experiments, fertility control was simulated by tubal ligation, ovariectomy or progesterone treatment. A once-off sterilisation of 50–75% of enclosed founder females considerably reduced reproductive output of ricefield rat populations until the end of the reproductive period. In house mice, similar success was achieved when a sterility level of 67% of female founders and offspring was maintained. Repeated antifertility treatments are required because of the much longer breeding period of house mice versus ricefield rats. Comparing the results of enclosure trials with the outcome of simulation models suggests that partial compensation of treatment effects can occur through enhanced reproduction of the remaining fertile females and improved survival of juveniles. However, such compensatory effects as well as behavioural consequences of sterility in field populations are not likely to prevent the management effect at the population level. The challenge for effective fertility control of small rodents in the field is the wide-scale delivery of an antifertility treatment to founders at the beginning of the breeding season and to fertile immigrants that are recruited into the population, which otherwise contribute to the reproductive output at the population level. Future research efforts should focus on species-specific techniques and on agents that can be effectively delivered via bait.

Hantaviruses have attracted increased public interest in recent years and are a clear example of an emerging virus. The enveloped virions of hantaviruses contain a tri-segmented single-stranded RNA genome of negative polarity. The initial discovery of hantaviruses dates back to investigations initiated after a large number of United Nations military personnel were affected by a severe disease during the Korean conflict in the 1950s. These investigations resulted in the discovery of Hantaan virus, the prototype species within the genus, in the striped field mouse (Apodemus agrarius). In the following years a large number of additional hantaviruses in other rodents were identified. The congruence in the phylogenetic relationship of the viruses and their rodent reservoirs was explained by a virus–host co-divergence. Further phylogenetic investigations and the discovery of novel hantaviruses indicated host-switch and subsequent host adaptation as an alternative evolution mechanism. In humans hantaviruses cause two disease syndromes, hemorrhagic fever with renal syndrome and hantavirus cardiopulmonary syndrome. Due to similarities in the disease symptoms it is currently suggested to unify both as "hantavirus disease." For detection of hantavirus infections a broad spectrum of molecular and serological diagnostic methods exists. Problems for hantavirus diagnostics in patients arise from the short-termed viremia and the strong cross-reactivity of sera against the nucleocapsid protein, frequently used in serological assays. The geographical distribution of the hantaviruses follows the range of their reservoir rodents. Human pathogenic hantaviruses are most likely distributed world-wide, but so far with little evidence for their presence in Africa, and Australia in particular. The recent discoveries of novel hantaviruses in shrews, moles and even bats raise questions about the origin and molecular evolution of hantaviruses. Importantly, the consequences of these novel viruses for public health are still unknown. The emergence of hantaviruses might be driven by various factors. Changes in small mammal reservoir population dynamics represent one of the major drivers for the occurrence of disease clusters and outbreaks. Long-term monitoring studies of small mammal reservoirs are needed to develop and validate prediction models and to implement them in early warning tools. Future hantavirus studies will profit from the application of Next Generation Sequencing technique, and the development of a reverse-genetics system.

Context Common voles (Microtus arvalis) are the most common vertebrate pests in central European agriculture. During outbreaks common vole populations can increase to an enormous number of individuals; however, this outbreak risk varies regionally. Aims In this study we tested whether topography and soil properties are suited to explain the regional variability in the outbreak risk of the common vole in Eastern Germany. This study provides the first detailed large-scale study of the association of site characteristics and small mammal outbreak risk at a regional scale. Methods Data on common vole outbreaks were recorded by active burrow counts at 82 sampling sites in Eastern Germany from almost four decades. Data on topography and soil properties – i.e. groundwater fluctuation index, soil air capacity, saturated hydraulic conductivity, soil class and elevation – were obtained from soil maps and a digital elevation model in a geographic information system and were related to outbreak risk classes, applying classification and regression trees (CART). Based on these results a map of the outbreak risk was developed for the area. Key results Classification and regression tree analyses revealed that the mean elevation, area-related percentage of Chernozem soils and soil air capacity were the site characteristics best suited to explain local variability in outbreak risk. In the northern German lowland, below an elevation of ~83 m above sea level, the outbreak risk is generally very low. The region of the central upland has an increased risk for outbreaks of common voles. Within the region of the central uplands the risk was again elevated if the area covered by Chernozem soils was higher than 36%, and increased further if the area covered by soils with a moderate soil air capacity was higher than 90%. Conclusions Topography and soil properties, and accordingly the character of a landscape, are static parameters that affect the local risk of common vole outbreak. Further detailed field investigations of soil properties are required to link the variation in regional outbreak risk to site characteristics with relevance to common vole ecology. Implications Areas of varying regional outbreak risk of common voles can be defined according to static site characteristics identified in this study. They can provide a spatial framework to relate dynamic parameters, such as meteorological parameters, as well as biological parameters, such as food availability, to common vole outbreaks. This could be used in the future to develop improved predictive models to forecast common vole outbreaks.

A technique to age wild house mice, Mus domesticus, in Australia using the dry weight of the eye lens based on known-age mice from semi-natural enclosures is described and presented for 3–32-week-old mice. At four sampling periods from November 2000 to September 2001, the age frequency distributions of free-living house mice were determined using this relationship. The distributions of ages shifted between seasons from relatively young animals at the beginning of the breeding season (November 2001), coinciding with low mouse abundance, to progressively older distributions in each sample as breeding continued, ending with the cessation of breeding and a population crash before the last sample. No significant difference was detected between the sexes at any of the four periods. These results are consistent with the suggestion that the formation of mouse outbreaks requires a shift in age structure towards younger mice.

Context. Overabundant rodents cause considerable crop damage and, in developing countries of South-east Asia, rodents can be an obstacle to attempts at alleviating poverty. Management is often based on the use of chemicals that can harm non-target species. Therefore, an effective and environmentally benign management approach such as ecologically based rodent management (EBRM) is desirable.
Aims. We compared the effectiveness of EBRM to that of conventional management on populations of rice-field rats (Rattus argentiventer).
Methods. The study was conducted as a large-scale replicated field trial in lowland irrigated rice fields in West Java, Indonesia. EBRM actions included habitat manipulations, removal of rats with trap barrier systems, coordinated rat-control campaigns and synchrony of cropping on the village level. We measured abundance, population structure, and breeding of rice-field rats as well as rice production and crop damage caused by rats.
Key results.Although there was no overall effect of the EBRM treatment on rat abundance, we found decreasing rat abundance in rice-field habitats at the late cropping stage in treated villages and a decrease in body size of rats. In addition, we found fewer reproducing females when EBRM was applied than with the application of conventional methods, whereas male reproductive condition did not decrease. Overall, there was a reduction in mean crop damage when EBRM was applied (4.4 ± 0.4% in treatments v. 2.5 ± 0.4% in experimental controls), which translated into 6% higher rice production.
Conclusions. The results demonstrated that EBRM is an appropriate approach to manage overabundant rodents in irrigated lowland rice-based agro-ecosystems and possibly in other agro-ecosystems. This will provide substantial benefits for smallholder farming communities in developing countries and most likely benefits for ecosystem health.
Implications. The EBRM approach should be used routinely in irrigated lowland rice crops that are at risk of damage by rice-field rats.

Zur Regulierung von Schadnagerpopulationen werden im Biozidbereich in Deutschland in den meisten Fällen Fraßköder mit blutgerinnungshemmenden (antikoagulanten) Wirkstoffen eingesetzt. Antikoagulante Rodentizide wirken bei allen warmblütigen Tieren, also auch bei Organismen, die nicht bekämpft werden sollen oder dürfen. Zudem sind die meisten dieser Wirkstoffe persistent, bioakkumulierend und toxisch. Um Nichtzielorganismen zu schützen und Einträge in die Umwelt zu minimieren, wurden bei der Biozid-Zulassung von antikoagulanten Rodentiziden verbindliche Risikominderungsmaßnahmen festgeschrieben. Die Effektivität dieser Maßnahmen ist jedoch kaum empirisch untersucht, so dass Wissensdefizite auch im Hinblick auf eine mögliche Optimierung bzw. Weiterentwicklung von Risikominderungsmaßnahmen bestehen. Im Rahmen dieses Forschungs- und Entwicklungsvorhabens wurden daher drei zentrale Aspekte mit Bezug auf den Schutz von Nichtzielorganismen näher betrachtet. Im ersten Teil wurde untersucht, wie sich die Ausbringung antikoagulanter Rodentizide in Köderstationen ausschließlich innerhalb von Gebäuden im Vergleich zum Einsatz in und um Gebäude auf das Auftreten blutgerinnungshemmender Wirkstoffe in freilebenden Nichtzielkleinsäugern auswirkt. Weiterhin wurden die Bewegungsmuster und Sterbeorte vergifteter Wanderratten auf Bauernhöfen dokumentiert, um daraus Rückschlüsse auf die mögliche Exposition von Beutegreifern ziehen zu können. Im zweiten Teil wurden Rückstände antikoagulanter Rodentizide in Rotfüchsen aus ländlichen und urbanen Räumen untersucht, um mögliche Unterschiede in der Exposition zu identifizieren. Außerdem wurde das Auftreten blutgerinnungshemmender Wirkstoffe in verschiedenen Singvögeln während Rattenbekämpfungen auf landwirtschaftlichen Betrieben analysiert. Im dritten Teil wurde versucht, die Ausbringung von Fraßködern in Köderstationen so zu gestalten, dass Nichtzielorganismen von der Köderannahme ausgeschlossen werden.

Rodents are a key pest to agricultural and rural island communities of the South Pacific, but there is limited information of their impact on the crops and livelihoods of small-scale farmers. The rodent pest community is known, but the type and scales of damage to different crops on different islands are unknown. Knowledge about rodent pest management in other geographical regions may not be directly transferable to the Pacific region. Many studies on islands have largely focussed on the eradication of rodents from uninhabited islands for conservation benefits. These broadscale eradication efforts are unlikely to translate to inhabited islands because of complex social and agricultural issues. The livelihoods, culture and customs of poor small-scale farmers in the South Pacific have a large bearing on the current management of rodents. The aim of the present review was to describe the rodent problems, impacts and management of rodents on South Pacific islands, and identify gaps for further research. We compared and contrasted two case studies. The situation in Papua New Guinea is emergent as several introduced rodent species are actively invading new areas with wide-ranging implications for human livelihoods and conservation. In Vanuatu, we show how rodent damage on cocoa plantations can be reduced by good orchard hygiene through pruning and weeding, which also has benefits for the management of black pod disease. We conclude that (1) damage levels are unknown and unreported, (2) the impacts on human health are unknown, (3) the relationships between the pest species and their food sources, breeding and movements are not known, and (4) the situation in Papua New Guinea may represent an emergent crisis that warrants further investigation. In addition, there is a need for greater understanding of the invasive history of pest rodents, so as to integrate biological information with management strategies. Ecologically based rodent management can be achieved on Pacific Islands, but only after significant well funded large-scale projects are established and rodent ecologists are trained. We can learn from experiences from other locations such as Southeast Asia to guide the way.

Rodents are a key pest to agricultural and rural island communities of the South Pacific, but there is limited information of their impact on the crops and livelihoods of small-scale farmers. The rodent pest community is known, but the type and scales of damage to different crops on different islands are unknown. Knowledge about rodent pest management in other geographical regions may not be directly transferable to the Pacific region. Many studies on islands have largely focussed on the eradication of rodents from uninhabited islands for conservation benefits. These broadscale eradication efforts are unlikely to translate to inhabited islands because of complex social and agricultural issues. The livelihoods, culture and customs of poor small-scale farmers in the South Pacific have a large bearing on the current management of rodents. The aim of the present review was to describe the rodent problems, impacts and management of rodents on South Pacific islands, and identify gaps for further research. We compared and contrasted two case studies. The situation in Papua New Guinea is emergent as several introduced rodent species are actively invading new areas with wide-ranging implications for human livelihoods and conservation. In Vanuatu, we show how rodent damage on cocoa plantations can be reduced by good orchard hygiene through pruning and weeding, which also has benefits for the management of black pod disease. We conclude that (1) damage levels are unknown and unreported, (2) the impacts on human health are unknown, (3) the relationships between the pest species and their food sources, breeding and movements are not known, and (4) the situation in Papua New Guinea may represent an emergent crisis that warrants further investigation. In addition, there is a need for greater understanding of the invasive history of pest rodents, so as to integrate biological information with management strategies. Ecologically based rodent management can be achieved on Pacific Islands, but only after significant well funded large-scale projects are established and rodent ecologists are trained. We can learn from experiences from other locations such as Southeast Asia to guide the way.

In Deutschland ist vor allem die Rötelmaus (Myodes glareolus) für die Übertragung humanpathogener Hantaviren verantwortlich (Puumalavirus, PUUV). Vor allem bei hohen Rötelmausdichten, die direkt und indirekt durch klimatische Bedingungen beeinflusst werden, kann es zu einer erhöhten Zahl von Humaninfektionen kommen. In diesem Projekt wurde ein wetterbasiertes Prognosemodel entwickelt, das Vorhersagen zu Populationsdichten und humanen PUUV-Inzidenzen auf Landkreisebene bis zu 1,5 Jahre im Voraus ermöglicht. Das Model bietet daher die Möglichkeit, entsprechende Gesundheitsdienste sowie die Bevölkerung frühzeitig zu sensibilisieren und damit mögliche PUUV-Epidemien einzudämmen.