Species assembly from a regional pool into local metacommunities and how they colonize and coexist over time and space is essential to understand how communities response to their environment including abiotic and biotic factors. In highly disturbed landscapes, connectivity of isolated habitat patches is essential to maintain biodiversity and the entire ecosystem functioning. In northeast Germany, a high density of the small water bodies called kettle holes, are good systems to study metacommunities due to their condition as "aquatic islands" suitable for hygrophilous species that are surrounded by in unsuitable matrix of crop fields. The main objective of this thesis was to infer the main ecological processes shaping plant communities and their response to the environment, from biodiversity patterns and key life-history traits involved in connectivity using ecological and genetic approaches; and to provide first insights of the role of kettle holes harboring wild-bee species as important mobile linkers connecting plant communities in ...
1. Concerns about insect declines are growing and the provisioning of ecosystem services like pollination may be threatened. To safeguard biodiversity, greening measures were introduced within the reform of the EU's Common Agricultural Policy. One measure commonly applied by farmers is the cultivation of nitrogen fixing crops. Although underlying studies are largely missing, this measure is criticized as providing no significant biodiversity benefit. 2. Using a landscape-scale approach, we selected 30 paired study landscapes (1 km × 1 km) in Germany, that is, 15 study landscapes with faba bean (FB) fields (Vicia faba L .) a nd 15 w ithout a ny g rain l egumes. F lower-visiting w ild b ees were recorded with transect walks at the field margins of different crops using a stratified sampling approach. We analysed the effect of FB cultivation and landscape composition on the abundance and species richness of wild bees as well as on the functional composition of the bee communities. 3. Bumblebee densities (Bombus spp. Latreille) were more than twice as high in FB compared to control landscapes after the flowering of the beans. Non-Bombus wild bee densities, however, were not affected by FB cultivation, but were enhanced by increasing amounts of semi-natural habitats (SNH). 4. After the beans' blooming had ceased, FB landscapes had a higher proportion of wild bees collecting pollen from Fabaceae than control landscapes. The communityweighted means for bee size, measured as intertegular distance, were not affected by FB cultivation, but we found smaller species and species with shorter tongues with an increasing percentage of SNH. 5. Synthesis and applications. The cultivation of faba bean Vicia faba L . s trongly increased bumblebee densities throughout the season. This indicates that also on-field greening measures can support biodiversity. Nevertheless, since only functional groups adapted to faba bean benefit, measures to promote seminatural habitats in agricultural landscapes need to be implemented. We conclude that the combination of on- and off-field measures is essential to maintain farmland biodiversity and the Common Agricultural Policy should furthermore promote both.
Pollination improves the yield of most crop species and contributes to one-third of global crop production, but comprehensive benefits including crop quality are still unknown. Hence, pollination is underestimated by international policies, which is particularly alarming in times of agricultural intensification and diminishing pollination services. In this study, exclusion experiments with strawberries showed bee pollination to improve fruit quality, quantity and market value compared with wind and self-pollination. Bee-pollinated fruits were heavier, had less malformations and reached higher commercial grades. They had increased redness and reduced sugar–acid–ratios and were firmer, thus improving the commercially important shelf life. Longer shelf life reduced fruit loss by at least 11%. This is accounting for 0.32 billion US$ of the 1.44 billion US$ provided by bee pollination to the total value of 2.90 billion US$ made with strawberry selling in the European Union 2009. The fruit quality and yield effects are driven by the pollination-mediated production of hormonal growth regulators, which occur in several pollination-dependent crops. Thus, our comprehensive findings should be transferable to a wide range of crops and demonstrate bee pollination to be a hitherto underestimated but vital and economically important determinant of fruit quality.
Es hat in der Gemeinsamen Agrarpolitik der Europäischen Union (GAP) seit 1992 zahlreiche mehr oder weniger erfolgreiche Reformschritte gegeben, die die gemeinsame Agrarpolitik generell liberalisiert, ihre Budget-Kosten reduziert und die handels- und produktionsverzerrenden Wirkungen abgebaut haben. Gleichwohl werden immer noch 42% des EU-Haushaltes für die Agrarpolitik aufgewendet und die Umweltwirkungen werden kontrovers diskutiert. Auch die Verteilung der Direktzahlungen zwischen den Landwirten und zwischen den Mitgliedern der Europäischen Union wird teilweise kontrovers diskutiert. Der Einsatz von marktverzerrenden Instrumenten wie Exportsubventionen wurde zwar reduziert, aber nicht vollständig beendet. Parallel zu den Beschlüssen zur finanziellen Vorausschau 2013-2020 hat die Europäische Kommission unter der Federführung von Agrarkommissar Dacian Ciolos und dem Directorate General für Landwirtschaft (DG Agri) zunächst 2010 in einem Thesenpapier neue Ziele und Herausforderungen für die Agrarpolitik benannt und im Oktober 2011 weitere Gesetzentwürfe für die Reform 2013 vorgelegt (Europäische Kommission 2011). Die EU-Mitgliedstaaten müssen sich im Zuge des Entscheidungsprozesses zur Reform positionieren. Im Prozess der Positionierung der Bundesregierung, auf deren Grundlage die Verhandlungsstrategie und das Abstimmungsverhalten der Bundesministerin Ilse Aigner im Rat der Europäischen Union basiert, spielt auch der Deutsche Bundestag als wichtigstes Legislativorgan in Deutschland, und speziell der Bundestagsausschuss für Ernährung, Landwirtschaft und Verbraucherschutz eine wichtige Rolle. Das vorliegende Papier ist der Versuch, aus Sicht der verschiedenen agrarwissenschaftlichen Disziplinen der Fakultäten in Göttingen und Witzenhausen zu den Reformentwürfen Stellung zu beziehen. Die gesammelten Argumente sind in Pro- und Contra-Argumente unterteilt. Daneben haben wir versucht, offene Fragen zu formulieren. Die Argumente sind dabei auch teilweise widersprüchlich, da sie von den Vertretern verschiedener Teildisziplinen formuliert wurden. Daher lässt sich aus diesem Papier keineswegs eine vollständige oder abschließende Analyse des Reformvorschlags ableiten. Am 11. Januar 2012 fand in Göttingen eine öffentliche Diskussion zwischen dem Bundestagsausschuss für Ernährung, Landwirtschaft und Verbraucherschutz und den Studierenden, wissenschaftlichen Mitarbeitern und Professoren der Göttinger Fakultät für Agrarwissenschaften über den Entwurf der EU-Kommission zur GAP-Reform 2013 statt. Eine frühere Fassung dieses Papiers diente zunächst als Grundlage für die gemeinsame Diskussion am 11. Januar 2012 in Göttingen und als Sammlung von Argumenten für den Diskussionsprozess innerhalb des Bundestages. Als Wissenschaftler sehen wir uns jedoch auch in der Pflicht, zu einer breiteren öffentlichen Diskussion beizutragen und unsere Erkenntnisse zum Diskurs zur GAP-Reform, der uns vermutlich noch durch die Jahre 2012 und 2013 begleiten wird, beizutragen. Daher haben wir uns dazu entschlossen, diese Sammlung von Analysen, Argumenten und offenen Fragen zu veröffentlichen.
In a cross-disciplinary project (LEGATO) combining inter- and transdisciplinary methods, we quantify the dependency of rice-dominated socio-ecological systems on ecosystem functions (ESF) and the ecosystem services (ESS) the integrated system provides. In the collaboration of a large team including geo- and bioscientists, economists, political and cultural scientists, the mutual influences of the biological, climate and soil conditions of the agricultural area and its surrounding natural landscape have been analysed. One focus was on sociocultural and economic backgrounds, another on local as well as regional land use intensity and biodiversity, and the potential impacts of future climate and land use change. LEGATO analysed characteristic elements of three service strands defined by the Millennium Ecosystem Assessment (MA): (a) provisioning services: nutrient cycling and crop production; (b) regulating services: biocontrol and pollination; and (c) cultural services: cultural identity and aesthetics. However, in line with much of the current ESS literature, what the MA called supporting services is treated as ESF within LEGATO. As a core output, LEGATO developed generally applicable principles of ecological engineering (EE), suitable for application in the context of future climate and land use change. EE is an emerging discipline, concerned with the design, monitoring and construction of ecosystems and aims at developing strategies to optimise ecosystem services through exploiting natural regulation mechanisms instead of suppressing them. Along these lines LEGATO also aims to create the knowledge base for decision-making for sustainable land management and livelihoods, including the provision of the corresponding governance and management strategies, technologies and system solutions.
