Context: Ecological Focus Areas (EFAs) were designed as part of the greening strategy of the common agricultural policy to conserve biodiversity in European farmland, prevent soil erosion and improve soil quality. Farmers receive economic support if they dedicate at least 5% of their arable farmland to any type of EFA, which can be selected from a list of options drawn up at the European Union level. However, EFAs have been criticized for failing to achieve their environmental goals and being ineffective in conserving farmland biodiversity, mainly because they are not spatially targeted and because they promote economic rather than ecological considerations in farm management decisions. Objectives: We used a spatially explicit approach to assess the influence of farm and field context as well as field terrain and soil conditions on the likelihood of whether or not a particular EFA type was implemented in a field. Methods: We used a multinomial model approach using field-level land use and management data from 879 farms that complied with the EFA policy in 2019 in the Mulde River Basin in Saxony, Germany. Geospatial environmental information was used to assess which predictor variables (related to farm context, field context or field terrain and soil conditions) increased the probability of a field being assigned to a particular EFA. We tested the hypothesis that productive EFAs are more often implemented on fields that are more suitable for agricultural production and that EFA options that are considered more valuable for biodiversity (e.g. non-productive EFAs) are allocated on fields that are less suitable for agricultural production. Results: We found that farms embedded in landscapes with a low proportion of small woody features or nature conservation areas mainly fulfilled the EFA policy with productive EFAs (e.g. nitrogen fixing crops). Conversely, farms with a higher proportion of small woody features or nature conservation areas were more likely to adopt non-productive EFAs. As predicted, large and compact fields with higher soil fertility and lower erosion risk were assigned to productive EFAs. Non-productive EFAs were placed on small fields in naturally disadvantaged areas. EFA options considered particularly beneficial for biodiversity, such as fallow land, were allocated far away from other semi-natural or nature protection areas. - Conclusions Our results highlight that the lack of spatial targeting of EFAs may result in EFA options being assigned to areas where their relative contribution to conservation goals is lower (e.g. farms with higher shares of protected areas) and absent in areas where they are most needed (e.g. high intensity farms). To ensure that greening policies actually promote biodiversity in European agriculture, incentives are needed to encourage greater uptake of ecologically effective measures on intensively used farms. These should be coupled with additional measures to conserve threatened species with specific habitat requirements.

In der vorliegenden Arbeit wurden wesentliche Einflussfaktoren auf die Entwicklung von hochstämmigen, extensiv gepflegten Obstbäumen untersucht. Der direkte Einfluss von Klimafaktoren auf die Entwicklung der Gehölze konnte nachgewiesen werden. Dazu wurden neue Klimakennziffern definiert und durch dendrochronologische Untersuchungen Beziehungen zum Wachstum der Gehölze hergestellt. Weiterhin konnten komplexe Wechselwirkungen von klimatischen Einflüssen, Bodenwasserverhältnissen und dem Resistenzverhalten der Bäume gegenüber Winterkälte aufgezeigt werden. Für die hochstämmigen Obstbäume wurden in dem Zeitraum von mehr als 120 Jahren klima- und standortabhängige Negativ- und Positivweiserjahre aufgezeigt. Die Beziehungen zwischen den vegetativen Leistungen der Bäume und den Boden-/ und Bodenwasserverhältnissen wurden an ca. 50- , 100- und 200 jährigen Apfelbäumen untersucht und Zusammenhänge zu den Bewertungsmodellen der Reichsbodenschätzung (Bodenarten) und der Mittelmaßstäbigen landwirtschaftlichen Standortkartierung der DDR (Leitbodenformen) dargestellt. Die Gehölze zeigten standortabhängig unterschiedliche Wachstumsintensitäten. Die höchsten Zuwachsleistungen wurden an Grund- bzw. Stauwasser beeinflussten Standorten erzielt. Der Einfluss der Bodenarten an Wasser beeinflussten Standorten war innerhalb der Obstarten gering, zeigte aber Obstart spezifische Unterschiede. Die Apfelbäume erreichten auf sand- bzw. lehmüberlagerten Tonstandorten höhere Zuwachsleistungen als auf Deckton-Standorten. Bei der Obstart Birne waren die Wuchsleistungen auf Tonböden höher als an sand- bzw. lehmüberlagerten Tonstandorten. Wuchsdepressionen traten bei der Obstart Birne erst bei schweren Tonstandorten auf. Die Bedeutung der Leitbodenformen und Bodenarten trat an den Grund- bzw. Stauwasser fernen Standorten deutlich hervor. Von den untersuchten Leitbodenformen wiesen die Tieflehm- Fahlerden unabhängig von den Bodenarten die beste obstbauliche Eignung auf. Für den extensiven Anbau von Apfelbäumen auf den Leitbodenformen Sand-Rosterde und Sand-Braunerde sollten nur Standorte mit mehr als 28 Bodenpunkten verwendet werden (Bodenarten Sl 4D, Sl 3D, lS 4D,lS 3D und SL 4D). Das individuelle Verhalten von alten Apfelsorten in der vegetativen und generativen Leistung wurde auf einer starkwachsenden Klonunterlage untersucht. Eine Abhängigkeit der Zuwachsleistung der Bäume von den verwendeten Sorten, der Ertragsbildung und von den Witterungserscheinungen wurde nachgewiesen. / This thesis studied the factors that exercise essential influence on the development of tall fruit trees in extensive cultivation. We were able to prove that climatic factors directly influence the development of the trees. For achieving this we defined new climatic indicators and established relationships with the growth of the trees by means of dendro-chronological investigations. Further, we were able to prove that complex interactions exist between the climatic influences, soil water conditions and the resistance of the trees against cold in winter. For the tall fruit trees we defined negative and positive indicator years within a period of more than 120 years depending upon the climate and the location. The relationships between the vegetative performance of the trees and the soil/ and soil water conditions were studied in apple trees aged 50, 100 and 200 years and we were able to prove correlations with the evaluation models of the Reichsbodenschätzung (assessment of soil types in the German Reich) and the medium scale agricultural location mapping of the GDR (East Germany) (dominant soil forms). The growth intensity of the trees differed according to their location. The highest growth rates were reached in locations which were influenced by groundwater and/or perched water. At the locations that were influenced by water the type of soil had only minor influence within the same kind of fruit trees, however, we discovered specific differences between the individual kinds of fruit. On locations with clayey soil covered by sand or loam the apple trees reached higher growth rates than at locations where the top soil was clay. Pear trees reached higher growth rates on clayey soils than on clayey soils covered by sand or loam. Growth depressions occurred in pear trees only at locations with heavy clayey soil. Locations that were far from groundwater or perched water made the influence of the dominating soil forms and soil types very clear. From among the dominating soil forms which we investigated the pale soils with deep loam showed to be the most suitable for growing fruit trees irrespective of the kind of fruit. For extensive cultivation of apple trees on the dominating soil forms of sandy rusty soil and sandy brown soils should be used only locations with more than 28 points for soil quality (soil types S1 4D, S1 3D, IS 4D, IS 3D and SL 4D). We studied the individual behaviour of ancient apple species with respect to the vegetative and generative performance on a strongly growing clone stock. We were able to prove that the growth performance of the trees depends upon the chosen species, the yield formation and weather conditions.