@article{WehrhanRaunekerSommer2016, author = {Wehrhan, Marc and Rauneker, Philipp and Sommer, Michael}, title = {UAV-Based Estimation of Carbon Exports from Heterogeneous Soil Landscapes-A Case Study from the CarboZALF Experimental Area}, series = {SENSORS}, volume = {16}, journal = {SENSORS}, publisher = {MDPI}, address = {Basel}, issn = {1424-8220}, doi = {10.3390/s16020255}, pages = {24}, year = {2016}, abstract = {The advantages of remote sensing using Unmanned Aerial Vehicles (UAVs) are a high spatial resolution of images, temporal flexibility and narrow-band spectral data from different wavelengths domains. This enables the detection of spatio-temporal dynamics of environmental variables, like plant-related carbon dynamics in agricultural landscapes. In this paper, we quantify spatial patterns of fresh phytomass and related carbon (C) export using imagery captured by a 12-band multispectral camera mounted on the fixed wing UAV Carolo P360. The study was performed in 2014 at the experimental area CarboZALF-D in NE Germany. From radiometrically corrected and calibrated images of lucerne (Medicago sativa), the performance of four commonly used vegetation indices (VIs) was tested using band combinations of six near-infrared bands. The highest correlation between ground-based measurements of fresh phytomass of lucerne and VIs was obtained for the Enhanced Vegetation Index (EVI) using near-infrared band b(899). The resulting map was transformed into dry phytomass and finally upscaled to total C export by harvest. The observed spatial variability at field- and plot-scale could be attributed to small-scale soil heterogeneity in part.}, language = {en} } @misc{WehrhanRaunekerSommer2016, author = {Wehrhan, Marc and Rauneker, Philipp and Sommer, Michael}, title = {UAV-Based estimation of carbon exports from heterogeneous soil landscapes}, series = {Sensors}, journal = {Sensors}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-407706}, pages = {24}, year = {2016}, abstract = {The advantages of remote sensing using Unmanned Aerial Vehicles (UAVs) are a high spatial resolution of images, temporal flexibility and narrow-band spectral data from different wavelengths domains. This enables the detection of spatio-temporal dynamics of environmental variables, like plant-related carbon dynamics in agricultural landscapes. In this paper, we quantify spatial patterns of fresh phytomass and related carbon (C) export using imagery captured by a 12-band multispectral camera mounted on the fixed wing UAV Carolo P360. The study was performed in 2014 at the experimental area CarboZALF-D in NE Germany. From radiometrically corrected and calibrated images of lucerne (Medicago sativa), the performance of four commonly used vegetation indices (VIs) was tested using band combinations of six near-infrared bands. The highest correlation between ground-based measurements of fresh phytomass of lucerne and VIs was obtained for the Enhanced Vegetation Index (EVI) using near-infrared band b(899). The resulting map was transformed into dry phytomass and finally upscaled to total C export by harvest. The observed spatial variability at field- and plot-scale could be attributed to small-scale soil heterogeneity in part.}, language = {en} } @misc{GallegoLlorenteSarahJonesetal.2016, author = {Gallego-Llorente, Marcos and Sarah, Connell and Jones, Eppie R. and Merrett, Deborah C. and Jeon, Y. and Eriksson, Anders and Siska, Veronika and Gamba, Cristina and Meiklejohn, Christopher and Beyer, Robert and Jeon, Sungwon and Cho, Yun Sung and Hofreiter, Michael and Bhak, Jong and Manica, Andrea and Pinhasi, Ron}, title = {The genetics of an early Neolithic pastoralist from the Zagros, Iran}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {952}, issn = {1866-8372}, doi = {10.25932/publishup-43935}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-439355}, pages = {9}, year = {2016}, abstract = {The agricultural transition profoundly changed human societies. We sequenced and analysed the first genome (1.39x) of an early Neolithic woman from Ganj Dareh, in the Zagros Mountains of Iran, a site with early evidence for an economy based on goat herding, ca. 10,000 BP. We show that Western Iran was inhabited by a population genetically most similar to hunter-gatherers from the Caucasus, but distinct from the Neolithic Anatolian people who later brought food production into Europe. The inhabitants of Ganj Dareh made little direct genetic contribution to modern European populations, suggesting those of the Central Zagros were somewhat isolated from other populations of the Fertile Crescent. Runs of homozygosity are of a similar length to those from Neolithic farmers, and shorter than those of Caucasus and Western Hunter-Gatherers, suggesting that the inhabitants of Ganj Dareh did not undergo the large population bottleneck suffered by their northern neighbours. While some degree of cultural diffusion between Anatolia, Western Iran and other neighbouring regions is possible, the genetic dissimilarity between early Anatolian farmers and the inhabitants of Ganj Dareh supports a model in which Neolithic societies in these areas were distinct.}, language = {en} } @article{NeillJankowskiBrandoetal.2017, author = {Neill, Christopher and Jankowski, KathiJo and Brando, Paulo M. and Coe, Michael T. and Deegan, Linda A. and Macedo, Marcia N. and Riskin, Shelby H. and Porder, Stephen and Elsenbeer, Helmut and Krusche, Alex V.}, title = {Surprisingly Modest Water Quality Impacts From Expansion and Intensification of Large-Sscale Commercial Agriculture in the Brazilian Amazon-Cerrado Region}, series = {Tropical conservation science}, volume = {10}, journal = {Tropical conservation science}, publisher = {Sage Publ.}, address = {Thousand Oaks}, issn = {1940-0829}, doi = {10.1177/1940082917720669}, pages = {5}, year = {2017}, abstract = {Large-scale commercial cropping of soybeans expanded in the tropical Amazon and Cerrado biomes of Brazil after 1990. More recently, cropping intensified from single-cropping of soybeans to double-cropping of soybeans with corn or cotton. Cropland expansion and intensification, and the accompanying use of mineral fertilizers, raise concerns about whether nutrient runoff and impacts to surface waters will be similar to those experienced in commercial cropland regions at temperate latitudes. We quantified water infiltration through soils, water yield, and streamwater chemistry in watersheds draining native tropical forest and single-and double-cropped areas on the level, deep, highly weathered soils where cropland expansion and intensification typically occurs. Although water yield increased four-fold from croplands, streamwater chemistry remained largely unchanged. Soil characteristics exerted important control over the movement of nitrogen (N) and phosphorus (P) into streams. High soil infiltration rates prevented surface erosion and movement of particulate P, while P fixation in surface soils restricted P movement to deeper soil layers. Nitrogen retention in deep soils, likely by anion exchange, also appeared to limit N leaching and export in streamwater from both single-and double-cropped watersheds that received nitrogen fertilizer. These mechanisms led to lower streamwater P and N concentrations and lower watershed N and P export than would be expected, based on studies from temperate croplands with similar cropping and fertilizer application practices.}, language = {en} } @article{MerfortBauerHumpenoederetal.2023, author = {Merfort, Leon and Bauer, Nico and Humpen{\"o}der, Florian and Klein, David and Strefler, Jessica and Popp, Alexander and Luderer, Gunnar and Kriegler, Elmar}, title = {State of global land regulation inadequate to control biofuel land-use-change emissions}, series = {Nature climate change}, volume = {13}, journal = {Nature climate change}, number = {7}, publisher = {Nature Publ. Group}, address = {London}, issn = {1758-678X}, doi = {10.1038/s41558-023-01711-7}, pages = {610 -- 612}, year = {2023}, abstract = {Under current land-use regulation, carbon dioxide emissions from biofuel production exceed those from fossil diesel combustion. Therefore, international agreements need to ensure the effective and globally comprehensive protection of natural land before modern bioenergy can effectively contribute to achieving carbon neutrality.}, language = {en} } @phdthesis{Rolf2020, author = {Rolf, Werner}, title = {Peri-urban farmland included in green infrastructure strategies promotes transformation pathways towards sustainable urban development}, doi = {10.25932/publishup-47700}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-477002}, school = {Universit{\"a}t Potsdam}, pages = {IV, 116}, year = {2020}, abstract = {Urbanization and agricultural land use are two of the main drivers of global changes with effects on ecosystem functions and human wellbeing. Green Infrastructure is a new approach in spatial planning contributing to sustainable urban development, and to address urban challenges, such as biodiversity conservation, climate change adaptation, green economy development, and social cohesion. Because the research focus has been mainly on open green space structures, such as parks, urban forest, green building, street green, but neglected spatial and functional potentials of utilizable agricultural land, this thesis aims at fill this gap. This cumulative thesis addresses how agricultural land in urban and peri-urban landscapes can contribute to the development of urban green infrastructure as a strategy to promote sustainable urban development. Therefore, a number of different research approaches have been applied. First, a quantitative, GIS-based modeling approach looked at spatial potentials, addressing the heterogeneity of peri-urban landscape that defines agricultural potentials and constraints. Second, a participatory approach was applied, involving stakeholder opinions to evaluate multiple urban functions and benefits. Finally, an evidence synthesis was conducted to assess the current state of research on evidence to support future policy making at different levels. The results contribute to the conceptual understanding of urban green infrastructures as a strategic spatial planning approach that incorporates inner-urban utilizable agricultural land and the agriculturally dominated landscape at the outer urban fringe. It highlights the proposition that the linkage of peri-urban farmland with the green infrastructure concept can contribute to a network of multifunctional green spaces to provide multiple benefits to the urban system and to successfully address urban challenges. Four strategies are introduced for spatial planning with the contribution of peri-urban farmland to a strategically planned multifunctional network, namely the connecting, the productive, the integrated, and the adapted way. Finally, this thesis sheds light on the opportunities that arise from the integration of the peri- urban farmland in the green infrastructure concept to support transformation towards a more sustainable urban development. In particular, the inherent core planning principle of multifunctionality endorses the idea of co-benefits that are considered crucial to trigger transformative processes. This work concludes that the linkage of peri-urban farmland with the green infrastructure concept is a promising action field for the development of new pathways for urban transformation towards sustainable urban development. Along with these outcomes, attention is drawn to limitations that remain to be addressed by future research, especially the identification of further mechanisms required to support policy integration at all levels.}, language = {en} } @article{LanghammerGrimm2020, author = {Langhammer, Maria and Grimm, Volker}, title = {Mitigating bioenergy-driven biodiversity decline}, series = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, volume = {416}, journal = {Ecological modelling : international journal on ecological modelling and engineering and systems ecolog}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0304-3800}, doi = {10.1016/j.ecolmodel.2019.108914}, pages = {13}, year = {2020}, abstract = {The cultivation of energy crops leads to direct and indirect land use changes that impair the biodiversity of the agricultural landscape. In our study, we analyse the effects of mitigation measures on the European brown hare (Lepus europaeus), which is directly affected by ongoing land use change and has experienced widespread decline throughout Europe since the 1960s. Therefore, we developed a spatially explicit and individual-based ecological model to study the effects of different landscape configurations and compositions on hare population development. As an input, we used two 4 x 4 km large model landscapes, which were generated by a landscape generator based on real field sizes and crop proportions and differed in average field size and crop composition. The crops grown annually are evaluated in terms of forage suitability, breeding suitability and crop richness for the hare. In six mitigation scenarios, we investigated the effects of a 10 \% increase in the following measures: (1) mixed silphie, (2) miscanthus, (3) grass-clover ley, (4) alfalfa, (5) set-aside, and (6) general crop richness. All mitigation measures had significant effects on hare population development. Compared to the base scenario, the relative change in hare abundance ranged from a factor of 0.56 in the grass-clover ley scenario to-0.16 in the miscanthus scenario. The mitigation measures of mixed silphie, grass-clover ley and increased crop richness led to distinct increases in hare abundance in both landscapes ( > 0.3). The results show that both landscape configuration and composition have a significant effect on hare population development, which responds particularly strongly to compositional changes. The increase in crop diversity, e.g., through the cultivation of alternative energy crops such as mixed silphie and grass-clover ley, proves to be beneficial for the brown hare.}, language = {en} } @misc{HeimLorenzKramerSchadtetal.2017, author = {Heim, Olga and Lorenz, Lukas and Kramer-Schadt, Stephanie and Jung, Kirsten and Voigt, Christian C. and Eccard, Jana}, title = {Landscape and scale-dependent spatial niches of bats foraging above intensively used arable fields}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch Naturwissenschaftliche Reihe}, number = {826}, doi = {10.25932/publishup-42816}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-428166}, pages = {17}, year = {2017}, abstract = {Introduction Bats are threatened by agricultural intensification, and although bat ecology in agricultural landscapes is in the focus of current research, the effects of interacting spatiotemporal factors on species-specific bat activity above farmland remain understudied. Our aim was to identify spatiotemporal factors and their interactions relevant for the activity of bat species above conventionally managed arable fields. Methods We repeatedly monitored relative bat activity above open arable fields in Germany using acoustic monitoring. We used site-related biotic and abiotic factors and landscape characteristics across five spatial scales, their combinations, and interactions to identify those factors which best explain variation in bat activity. Results Numerous interactions between landscape characteristics and the insect abundance affected bat activity above fields. For instance, Pipistrellus pipistrellus became more active with increasing insect abundance, but only above fields with a low proportion of woody vegetation cover in the surroundings. Additionally, the level of bat activity in summer depended on landscape characteristics. For example, the activity of Pipistrellus nathusii was relatively low in summer above fields that were surrounded by vegetation patches with a high degree of edge complexity (e.g., hedgerow). However, the activity remained at a relatively high level and did not differ between seasons above fields that were surrounded by vegetation patches with a low degree of edge complexity (e.g., roundly shaped forest patch). Conclusions Our results revealed that landscape characteristics and their interactions with insect abundance affected bat activity above conventionally managed fields and highlighted the opportunistic foraging behavior of bats. To improve the conditions for bats in agricultural landscapes, we recommend re-establishing landscape heterogeneity to protect aquatic habitats and to increase arthropod availability.}, language = {en} } @article{BizicIonescuKarnataketal.2022, author = {Bizic, Mina and Ionescu, Danny and Karnatak, Rajat and Musseau, Camille L. and Onandia, Gabriela and Berger, Stella A. and Nejstgaard, Jens C. and Lischeid, Gunnar and Gessner, Mark O. and Wollrab, Sabine and Grossart, Hans-Peter}, title = {Land-use type temporarily affects active pond community structure but not gene expression patterns}, series = {Molecular ecology}, volume = {31}, journal = {Molecular ecology}, number = {6}, publisher = {Wiley}, address = {Hoboken}, issn = {0962-1083}, doi = {10.1111/mec.16348}, pages = {1716 -- 1734}, year = {2022}, abstract = {Changes in land use and agricultural intensification threaten biodiversity and ecosystem functioning of small water bodies. We studied 67 kettle holes (KH) in an agricultural landscape in northeastern Germany using landscape-scale metatranscriptomics to understand the responses of active bacterial, archaeal and eukaryotic communities to land-use type. These KH are proxies of the millions of small standing water bodies of glacial origin spread across the northern hemisphere. Like other landscapes in Europe, the study area has been used for intensive agriculture since the 1950s. In contrast to a parallel environmental DNA study that suggests the homogenization of biodiversity across KH, conceivably resulting from long-lasting intensive agriculture, land-use type affected the structure of the active KH communities during spring crop fertilization, but not a month later. This effect was more pronounced for eukaryotes than for bacteria. In contrast, gene expression patterns did not differ between months or across land-use types, suggesting a high degree of functional redundancy across the KH communities. Variability in gene expression was best explained by active bacterial and eukaryotic community structures, suggesting that these changes in functioning are primarily driven by interactions between organisms. Our results indicate that influences of the surrounding landscape result in temporary changes in the activity of different community members. Thus, even in KH where biodiversity has been homogenized, communities continue to respond to land management. This potential needs to be considered when developing sustainable management options for restoration purposes and for successful mitigation of further biodiversity loss in agricultural landscapes.}, language = {en} } @article{KalkuhlSchwerhoffWaha2020, author = {Kalkuhl, Matthias and Schwerhoff, Gregor and Waha, Katharina}, title = {Land tenure, climate and risk management}, series = {Ecological economics}, volume = {171}, journal = {Ecological economics}, publisher = {Elsevier Science}, address = {Amsterdam [u.a.]}, issn = {0921-8009}, doi = {10.1016/j.ecolecon.2019.106573}, pages = {16}, year = {2020}, abstract = {We analyze to what extent climate conditions affect the prevalence of sharecropping as a form of traditional land tenure. We investigate how sharecropping tenure is related to climate risk and how it interacts with fertilizer use and livestock ownership that both influence production risk. We first develop a stylized theoretical model to illustrate the role of climate for land tenure and production. Our empirical analysis is based on more than 9000 households with considerable heterogeneity in climate conditions across several African countries. We find that farmers in areas with low precipitation are more likely to be sharecroppers. We further find evidence for risk management interaction effects as sharecropping farmers are less likely to own livestock and more likely to use fertilizer. In economies where formal kinds of insurance are unavailable, sharecropping thus functions as a form of insurance and reduces the need for potentially costly risk management strategies.}, language = {en} } @phdthesis{Kemper2023, author = {Kemper, Tarek}, title = {KLIMAGRAR - Neue Methoden der Begleitforschung am Beispiel des klimagerechten Handelns in der Landwirtschaft}, doi = {10.25932/publishup-60192}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-601924}, school = {Universit{\"a}t Potsdam}, pages = {109}, year = {2023}, abstract = {In Forschungsprogrammen werden zahlreiche Akteure mit unterschiedlichen Hintergr{\"u}nden und fachlichen Expertisen in Einzel- oder Verbundvorhaben vereint, die jedoch weitestgehend unabh{\"a}ngig voneinander durchgef{\"u}hrt werden. Vor dem Hintergrund, dass gesamtgesellschaftliche Herausforderungen wie die globale Erw{\"a}rmung zunehmend disziplin{\"u}bergreifende L{\"o}sungsans{\"a}tze erfordern, sollten Vernetzungs- und Transferprozesse in Forschungsprogrammen st{\"a}rker in den Fokus r{\"u}cken. Mit der Implementierung einer Begleitforschung kann dieser Forderung Rechnung getragen werden. Begleitforschung unterscheidet sich in ihrer Herangehensweise und ihrer Zielvorstellung von den „{\"u}blichen" Projekten und kann in unterschiedlichen theoretischen Reinformen auftreten. Verk{\"u}rzt dargestellt agiert sie entweder (1) inhaltlich komplement{\"a}r zu den jeweiligen Forschungsprojekten, (2) auf einer Metaebene mit Fokus auf die Prozesse im Forschungsprogramm oder (3) als integrierende, synthetisierende Instanz, f{\"u}r die die Vernetzung der Projekte im Forschungsprogramm sowie der Wissenstransfer von Bedeutung sind. Zwar sind diese Formen analytisch in theoretische Reinformen trennbar, in der Praxis ergibt sich in der Regel jedoch ein Mix aus allen dreien. In diesem Zusammenhang schließt die vorliegende Dissertation als erg{\"a}nzende Studie an bisherige Ans{\"a}tze zum methodischen Handwerkszeug der Begleitforschung an und fokussiert auf folgende Fragestellungen: Auf welcher Basis kann die Vernetzung der Akteure in einem Forschungsprogramm durchgef{\"u}hrt werden, um diese effektiv zusammenzubringen? Welche weiteren methodischen Elemente sollten daran ansetzen, um einen Mehrwert zu generieren, der die Summe der Einzelergebnisse des Forschungsprogrammes {\"u}bersteigt? Von welcher Art kann dann ein solcher Mehrwert sein und welche Rolle spielt dabei die Begleitforschung? Das erste methodische Element bildet die Erhebung und Aufbereitung einer Ausgangsdatenbasis. Durch eine auf semantischer Analyse basierenden Verschlagwortung projektbezogener Texte l{\"a}sst sich eine umfassende Datenbasis aus den Inhalten der Forschungsprojekte generieren. Die Schlagw{\"o}rter werden dabei anhand eines kontrollierten Vokabulars in einem Schlagwortkatalog strukturiert. Parallel dazu werden sie wiederum den jeweiligen Projekten zugeordnet, wodurch diese thematische Merkmale erhalten. Um thematische {\"U}berschneidungen zwischen Forschungsprojekten sichtbar und interpretierbar zu machen, beinhaltet das zweite Element Ans{\"a}tze zur Visualisierung. Dazu werden die Informationen in einen Netzwerkgraphen transferiert, der sowohl alle im Forschungsprogramm involvierten Projekte als auch die identifizierten Schlagw{\"o}rter in Relation zueinander abbilden kann. So kann zum Beispiel sichtbar gemacht werden, welche Forschungsprojekte sich auf Basis ihrer Inhalte „n{\"a}her" sind als andere. Genau diese Information wird im dritten methodischen Element als Planungsgrundlage f{\"u}r unterschiedliche Veranstaltungsformate wie Arbeitstagungen oder Transferwerkst{\"a}tten genutzt. Das vierte methodische Element umfasst die Synthesebildung. Diese gestaltet sich als Prozess {\"u}ber den gesamten Zeitraum der Zusammenarbeit zwischen Begleitforschung und den weiteren Forschungsprojekten hinweg, da in die Synthese unter anderem Zwischen-, Teil- und Endergebnisse der Projekte einfließen, genauso wie Inhalte aus den unterschiedlichen Veranstaltungen. Letztendlich ist dieses vierte Element auch das Mittel, um aus den integrierten und synthetisierten Informationen Handlungsempfehlungen f{\"u}r zuk{\"u}nftige Vorhaben abzuleiten. Die Erarbeitung der methodischen Elemente erfolgte im laufenden Prozess des Begleitforschungsprojektes KlimAgrar, welches der vorliegenden Dissertation als Fallbeispiel dient und dessen Hintergr{\"u}nde in der Thematik Klimaschutz und Klimaanpassung in der Landwirtschaft im Text ausf{\"u}hrlich erl{\"a}utert werden.}, language = {de} } @phdthesis{Šedova2022, author = {Šedov{\´a}, Barbora}, title = {Heterogeneous effects of weather and climate change on human migration}, doi = {10.25932/publishup-53673}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-536733}, school = {Universit{\"a}t Potsdam}, pages = {xix, 284}, year = {2022}, abstract = {While estimated numbers of past and future climate migrants are alarming, the growing empirical evidence suggests that the association between adverse climate-related events and migration is not universally positive. This dissertation seeks to advance our understanding of when and how climate migration emerges by analyzing heterogeneous climatic influences on migration in low- and middle-income countries. To this end, it draws on established economic theories of migration, datasets from physical and social sciences, causal inference techniques and approaches from systematic literature review. In three of its five chapters, I estimate causal effects of processes of climate change on inequality and migration in India and Sub-Saharan Africa. By employing interaction terms and by analyzing sub-samples of data, I explore how these relationships differ for various segments of the population. In the remaining two chapters, I present two systematic literature reviews. First, I undertake a comprehensive meta-regression analysis of the econometric climate migration literature to summarize general climate migration patterns and explain the conflicting findings. Second, motivated by the broad range of approaches in the field, I examine the literature from a methodological perspective to provide best practice guidelines for studying climate migration empirically. Overall, the evidence from this dissertation shows that climatic influences on human migration are highly heterogeneous. Whether adverse climate-related impacts materialize in migration depends on the socio-economic characteristics of the individual households, such as wealth, level of education, agricultural dependence or access to adaptation technologies and insurance. For instance, I show that while adverse climatic shocks are generally associated with an increase in migration in rural India, they reduce migration in the agricultural context of Sub-Saharan Africa, where the average wealth levels are much lower so that households largely cannot afford the upfront costs of moving. I find that unlike local climatic shocks which primarily enhance internal migration to cities and hence accelerate urbanization, shocks transmitted via agricultural producer prices increase migration to neighboring countries, likely due to the simultaneous decrease in real income in nearby urban areas. These findings advance our current understanding by showing when and how economic agents respond to climatic events, thus providing explicit contexts and mechanisms of climate change effects on migration in the future. The resulting collection of findings can guide policy interventions to avoid or mitigate any present and future welfare losses from climate change-related migration choices.}, language = {en} } @misc{MayerUllmannSundeetal.2018, author = {Mayer, Martin and Ullmann, Wiebke and Sunde, Peter and Fischer, Christina and Blaum, Niels}, title = {Habitat selection by the European hare in arable landscapes}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {1076}, issn = {1866-8372}, doi = {10.25932/publishup-46789}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-467891}, pages = {17}, year = {2018}, abstract = {Agricultural land-use practices have intensified over the last decades, leading to population declines of various farmland species, including the European hare (Lepus europaeus). In many European countries, arable fields dominate agricultural landscapes. Compared to pastures, arable land is highly variable, resulting in a large spatial variation of food and cover for wildlife over the course of the year, which potentially affects habitat selection by hares. Here, we investigated within-home-range habitat selection by hares in arable areas in Denmark and Germany to identify habitat requirements for their conservation. We hypothesized that hare habitat selection would depend on local habitat structure, that is, vegetation height, but also on agricultural field size, vegetation type, and proximity to field edges. Active hares generally selected for short vegetation (1-25 cm) and avoided higher vegetation and bare ground, especially when fields were comparatively larger. Vegetation >50 cm potentially restricts hares from entering parts of their home range and does not provide good forage, the latter also being the case on bare ground. The vegetation type was important for habitat selection by inactive hares, with fabaceae, fallow, and maize being selected for, potentially providing both cover and forage. Our results indicate that patches of shorter vegetation could improve the forage quality and habitat accessibility for hares, especially in areas with large monocultures. Thus, policymakers should aim to increase areas with short vegetation throughout the year. Further, permanent set-asides, like fallow and wildflower areas, would provide year-round cover for inactive hares. Finally, the reduction in field sizes would increase the density of field margins, and farming different crop types within small areas could improve the habitat for hares and other farmland species.}, language = {en} } @article{MayerUllmannSundeetal.2018, author = {Mayer, Martin and Ullmann, Wiebke and Sunde, Peter and Fischer, Christina and Blaum, Niels}, title = {Habitat selection by the European hare in arable landscapes}, series = {Ecology and Evolution}, volume = {8}, journal = {Ecology and Evolution}, number = {23}, publisher = {Wiley}, address = {Hoboken}, issn = {2045-7758}, doi = {10.1002/ece3.4613}, pages = {11619 -- 11633}, year = {2018}, abstract = {Agricultural land-use practices have intensified over the last decades, leading to population declines of various farmland species, including the European hare (Lepus europaeus). In many European countries, arable fields dominate agricultural landscapes. Compared to pastures, arable land is highly variable, resulting in a large spatial variation of food and cover for wildlife over the course of the year, which potentially affects habitat selection by hares. Here, we investigated within-home-range habitat selection by hares in arable areas in Denmark and Germany to identify habitat requirements for their conservation. We hypothesized that hare habitat selection would depend on local habitat structure, that is, vegetation height, but also on agricultural field size, vegetation type, and proximity to field edges. Active hares generally selected for short vegetation (1-25 cm) and avoided higher vegetation and bare ground, especially when fields were comparatively larger. Vegetation >50 cm potentially restricts hares from entering parts of their home range and does not provide good forage, the latter also being the case on bare ground. The vegetation type was important for habitat selection by inactive hares, with fabaceae, fallow, and maize being selected for, potentially providing both cover and forage. Our results indicate that patches of shorter vegetation could improve the forage quality and habitat accessibility for hares, especially in areas with large monocultures. Thus, policymakers should aim to increase areas with short vegetation throughout the year. Further, permanent set-asides, like fallow and wildflower areas, would provide year-round cover for inactive hares. Finally, the reduction in field sizes would increase the density of field margins, and farming different crop types within small areas could improve the habitat for hares and other farmland species.}, language = {en} } @misc{PradhanFischerVelthuizenetal.2015, author = {Pradhan, Prajal and Fischer, G{\"u}nther and Velthuizen, Harrij van and Reusser, Dominik Edwin and Kropp, J{\"u}rgen}, title = {Closing yield gaps}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {491}, issn = {1866-8372}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-408105}, pages = {18}, year = {2015}, abstract = {Global food production needs to be increased by 60-110\% between 2005 and 2050 to meet growing food and feed demand. Intensification and/or expansion of agriculture are the two main options available to meet the growing crop demands. Land conversion to expand cultivated land increases GHG emissions and impacts biodiversity and ecosystem services. Closing yield gaps to attain potential yields may be a viable option to increase the global crop production. Traditional methods of agricultural intensification often have negative externalities. Therefore, there is a need to explore location-specific methods of sustainable agricultural intensification. We identified regions where the achievement of potential crop calorie production on currently cultivated land will meet the present and future food demand based on scenario analyses considering population growth and changes in dietary habits. By closing yield gaps in the current irrigated and rain-fed cultivated land, about 24\% and 80\% more crop calories can respectively be produced compared to 2000. Most countries will reach food self-sufficiency or improve their current food self-sufficiency levels if potential crop production levels are achieved. As a novel approach, we defined specific input and agricultural management strategies required to achieve the potential production by overcoming biophysical and socioeconomic constraints causing yield gaps. The management strategies include: fertilizers, pesticides, advanced soil management, land improvement, management strategies coping with weather induced yield variability, and improving market accessibility. Finally, we estimated the required fertilizers (N, P2O5, and K2O) to attain the potential yields. Globally, N-fertilizer application needs to increase by 45-73\%, P2O5-fertilizer by 22-46\%, and K2O-fertilizer by 2-3 times compared to the year 2010 to attain potential crop production. The sustainability of such agricultural intensification largely depends on the way management strategies for closing yield gaps are chosen and implemented.}, language = {en} } @phdthesis{Waha2012, author = {Waha, Katharina}, title = {Climate change impacts on agricultural vegetation in sub-Saharan Africa}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-64717}, school = {Universit{\"a}t Potsdam}, year = {2012}, abstract = {Agriculture is one of the most important human activities providing food and more agricultural goods for seven billion people around the world and is of special importance in sub-Saharan Africa. The majority of people depends on the agricultural sector for their livelihoods and will suffer from negative climate change impacts on agriculture until the middle and end of the 21st century, even more if weak governments, economic crises or violent conflicts endanger the countries' food security. The impact of temperature increases and changing precipitation patterns on agricultural vegetation motivated this thesis in the first place. Analyzing the potentials of reducing negative climate change impacts by adapting crop management to changing climate is a second objective of the thesis. As a precondition for simulating climate change impacts on agricultural crops with a global crop model first the timing of sowing in the tropics was improved and validated as this is an important factor determining the length and timing of the crops´ development phases, the occurrence of water stress and final crop yield. Crop yields are projected to decline in most regions which is evident from the results of this thesis, but the uncertainties that exist in climate projections and in the efficiency of adaptation options because of political, economical or institutional obstacles have to be considered. The effect of temperature increases and changing precipitation patterns on crop yields can be analyzed separately and varies in space across the continent. Southern Africa is clearly the region most susceptible to climate change, especially to precipitation changes. The Sahel north of 13° N and parts of Eastern Africa with short growing seasons below 120 days and limited wet season precipitation of less than 500 mm are also vulnerable to precipitation changes while in most other part of East and Central Africa, in contrast, the effect of temperature increase on crops overbalances the precipitation effect and is most pronounced in a band stretching from Angola to Ethiopia in the 2060s. The results of this thesis confirm the findings from previous studies on the magnitude of climate change impact on crops in sub-Saharan Africa but beyond that helps to understand the drivers of these changes and the potential of certain management strategies for adaptation in more detail. Crop yield changes depend on the initial growing conditions, on the magnitude of climate change, and on the crop, cropping system and adaptive capacity of African farmers which is only now evident from this comprehensive study for sub-Saharan Africa. Furthermore this study improves the representation of tropical cropping systems in a global crop model and considers the major food crops cultivated in sub-Saharan Africa and climate change impacts throughout the continent.}, language = {en} } @article{Eccard2022, author = {Eccard, Jana}, title = {Can rolling composite wildflower blocks increase biodiversity in agricultural landscapes better than wildflowers strips?}, series = {Journal of applied ecology : an official journal of the British Ecological Society}, volume = {59}, journal = {Journal of applied ecology : an official journal of the British Ecological Society}, number = {5}, publisher = {Wiley-Blackwell}, address = {Oxford}, issn = {0021-8901}, doi = {10.1111/1365-2664.14147}, pages = {1172 -- 1177}, year = {2022}, abstract = {Biodiversity and abundance of wildlife has dramatically declined in agricultural landscapes. Sown, short-lived wildflower (WF) strips along the margins of crop fields are a widespread and often subsidised in agri-environmental schemes, intended to enhance biodiversity, provide refuges for wild plant and arthropod populations and to provide ecosystem services to crops. Meanwhile, WF elements are also criticised, since their functionality decreases with plant succession, the removal of aged WF strip poses an ecological trap for the attracted arthropod populations and only common and mobile species benefit. Further, insects in WF strips are impacted by pesticides from agricultural fields due to shared boundaries with crop fields and by edge effects. The performance of the measure could be improved by combining several WF strips of different successional stages, each harbouring a unique community of plants and arthropods, into persistent, composite WF block, where successional stages exist in parallel. Monitoring data on many taxa in the literature shows, that a third of species are temporarily present in an ageing WF stip, thus offering composite WF blocks should increase cumulative species richness by 28\%-39\% compared to annual richness in WF strips. Persistence of composite WF blocks would offer reliable refuge for animal and plant populations, also supporting their predators and herbivores. Further, WF blocks have less boundaries to crops compared to WF strips of the same area, and are less impacted by edge effects and pesticides. Policy implications. Here I suggest a change of conservation practice changing from successional WF strips to composite WF blocks. By regular removal and replacement of aged WF strips either within the block (rotational) or at its margins (rolling), the habitat heterogeneity in composite WF block could be perpetuated. Rolling composite WF blocks change locations over years, and the original location can be reconverted to arable land while a nearby WF block is still available to wildlife. A change in agricultural schemes would be necessary, since in some European countries clustered WF strips are explicitly not subsidised.}, language = {en} } @article{MerfortBauerHumpenoederetal.2023, author = {Merfort, Leon and Bauer, Nico and Humpen{\"o}der, Florian and Klein, David and Strefler, Jessica and Popp, Alexander and Luderer, Gunnar and Kriegler, Elmar}, title = {Bioenergy-induced land-use-change emissions with sectorally fragmented policies}, series = {Nature climate change}, volume = {13}, journal = {Nature climate change}, number = {7}, publisher = {Nature Publ. Group}, address = {London}, issn = {1758-678X}, doi = {10.1038/s41558-023-01697-2}, pages = {685 -- 692}, year = {2023}, abstract = {Controlling bioenergy-induced land-use-change emissions is key to exploiting bioenergy for climate change mitigation. However, the effect of different land-use and energy sector policies on specific bioenergy emissions has not been studied so far. Using the global integrated assessment model REMIND-MAgPIE, we derive a biofuel emission factor (EF) for different policy frameworks. We find that a uniform price on emissions from both sectors keeps biofuel emissions at 12 kg CO2 GJ-1. However, without land-use regulation, the EF increases substantially (64 kg CO2 GJ-1 over 80 years, 92 kg CO2 GJ-1 over 30 years). We also find that comprehensive coverage (>90\%) of carbon-rich land areas worldwide is key to containing land-use emissions. Pricing emissions indirectly on the level of bioenergy consumption reduces total emissions by cutting bioenergy demand but fails to reduce the average EF. In the absence of comprehensive and timely land-use regulation, bioenergy thus may contribute less to climate change mitigation than assumed previously.}, language = {en} } @article{GeversHoyeToppingetal.2011, author = {Gevers, Jana and Hoye, Toke Thomas and Topping, Chris John and Glemnitz, Michael and Schroeder, Boris}, title = {Biodiversity and the mitigation of climate change through bioenergy impacts of increased maize cultivation on farmland wildlife}, series = {Global change biology : Bioenergy}, volume = {3}, journal = {Global change biology : Bioenergy}, number = {6}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1757-1693}, doi = {10.1111/j.1757-1707.2011.01104.x}, pages = {472 -- 482}, year = {2011}, abstract = {The public promotion of renewable energies is expected to increase the number of biogas plants and stimulate energy crops cultivation (e. g. maize) in Germany. In order to assess the indirect effects of the resulting land-use changes on biodiversity, we developed six land-use scenarios and simulated the responses of six farmland wildlife species with the spatially explicit agent-based model system ALMaSS. The scenarios differed in composition and spatial configuration of arable crops. We implemented scenarios where maize for energy production replaced 15\% and 30\% of the area covered by other cash crops. Biogas maize farms were either randomly distributed or located within small or large aggregation clusters. The animal species investigated were skylark (Alauda arvensis), grey partridge (Perdix perdix), European brown hare (Lepus europaeus), field vole (Microtus agrestis), a linyphiid spider (Erigone atra) and a carabid beetle (Bembidion lampros). The changes in crop composition had a negative effect on the population sizes of skylark, partridge and hare and a positive effect on the population sizes of spider and beetle and no effect on the population size of vole. An aggregated cultivation of maize amplified these effects for skylark. Species responses to changes in the crop composition were consistent across three differently structured landscapes. Our work suggests that with the compliance to some recommendations, negative effects of biogas-related land-use change on the populations of the six representative farmland species can largely be avoided.}, language = {en} } @article{WehrhanSommer2021, author = {Wehrhan, Marc and Sommer, Michael}, title = {A parsimonious approach to estimate soil organic carbon applying Unmanned Aerial System (UAS) multispectral imagery and the topographic position index in a heterogeneous soil landscape}, series = {Remote sensing / Molecular Diversity Preservation International (MDPI)}, volume = {13}, journal = {Remote sensing / Molecular Diversity Preservation International (MDPI)}, number = {18}, publisher = {MDPI}, address = {Basel}, issn = {2072-4292}, doi = {10.3390/rs13183557}, pages = {20}, year = {2021}, abstract = {Remote sensing plays an increasingly key role in the determination of soil organic carbon (SOC) stored in agriculturally managed topsoils at the regional and field scales. Contemporary Unmanned Aerial Systems (UAS) carrying low-cost and lightweight multispectral sensors provide high spatial resolution imagery (<10 cm). These capabilities allow integrate of UAS-derived soil data and maps into digitalized workflows for sustainable agriculture. However, the common situation of scarce soil data at field scale might be an obstacle for accurate digital soil mapping. In our case study we tested a fixed-wing UAS equipped with visible and near infrared (VIS-NIR) sensors to estimate topsoil SOC distribution at two fields under the constraint of limited sampling points, which were selected by pedological knowledge. They represent all releva nt soil types along an erosion-deposition gradient; hence, the full feature space in terms of topsoils' SOC status. We included the Topographic Position Index (TPI) as a co-variate for SOC prediction. Our study was performed in a soil landscape of hummocky ground moraines, which represent a significant of global arable land. Herein, small scale soil variability is mainly driven by tillage erosion which, in turn, is strongly dependent on topography. Relationships between SOC, TPI and spectral information were tested by Multiple Linear Regression (MLR) using: (i) single field data (local approach) and (ii) data from both fields (pooled approach). The highest prediction performance determined by a leave-one-out-cross-validation (LOOCV) was obtained for the models using the reflectance at 570 nm in conjunction with the TPI as explanatory variables for the local approach (coefficient of determination (R-2) = 0.91; root mean square error (RMSE) = 0.11\% and R-2 = 0.48; RMSE = 0.33, respectively). The local MLR models developed with both reflectance and TPI using values from all points showed high correlations and low prediction errors for SOC content (R-2 = 0.88, RMSE = 0.07\%; R-2 = 0.79, RMSE = 0.06\%, respectively). The comparison with an enlarged dataset consisting of all points from both fields (pooled approach) showed no improvement of the prediction accuracy but yielded decreased prediction errors. Lastly, the local MLR models were applied to the data of the respective other field to evaluate the cross-field prediction ability. The spatial SOC pattern generally remains unaffected on both fields; differences, however, occur concerning the predicted SOC level. Our results indicate a high potential of the combination of UAS-based remote sensing and environmental covariates, such as terrain attributes, for the prediction of topsoil SOC content at the field scale. The temporal flexibility of UAS offer the opportunity to optimize flight conditions including weather and soil surface status (plant cover or residuals, moisture and roughness) which, otherwise, might obscure the relationship between spectral data and SOC content. Pedologically targeted selection of soil samples for model development appears to be the key for an efficient and effective prediction even with a small dataset.}, language = {en} } @misc{FrielerLevermannElliottetal.2015, author = {Frieler, Katja and Levermann, Anders and Elliott, J. and Heinke, J. and Arneth, A. and Bierkens, M. F. P. and Ciais, Philippe and Clark, D. B. and Deryng, D. and Doell, P. and Falloon, P. and Fekete, B. and Folberth, Christian and Friend, A. D. and Gellhorn, C. and Gosling, S. N. and Haddeland, I. and Khabarov, N. and Lomas, M. and Masaki, Y. and Nishina, K. and Neumann, K. and Oki, T. and Pavlick, R. and Ruane, A. C. and Schmid, E. and Schmitz, C. and Stacke, T. and Stehfest, E. and Tang, Q. and Wisser, D. and Huber, V. and Piontek, Franziska and Warszawski, L. and Schewe, Jacob and Lotze-Campen, Hermann and Schellnhuber, Hans Joachim}, title = {A framework for the cross-sectoral integration of multi-model impact projections}, series = {Earth system dynamics}, journal = {Earth system dynamics}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-407968}, pages = {14}, year = {2015}, abstract = {Climate change and its impacts already pose considerable challenges for societies that will further increase with global warming (IPCC, 2014a, b). Uncertainties of the climatic response to greenhouse gas emissions include the potential passing of large-scale tipping points (e.g. Lenton et al., 2008; Levermann et al., 2012; Schellnhuber, 2010) and changes in extreme meteorological events (Field et al., 2012) with complex impacts on societies (Hallegatte et al., 2013). Thus climate change mitigation is considered a necessary societal response for avoiding uncontrollable impacts (Conference of the Parties, 2010). On the other hand, large-scale climate change mitigation itself implies fundamental changes in, for example, the global energy system. The associated challenges come on top of others that derive from equally important ethical imperatives like the fulfilment of increasing food demand that may draw on the same resources. For example, ensuring food security for a growing population may require an expansion of cropland, thereby reducing natural carbon sinks or the area available for bio-energy production. So far, available studies addressing this problem have relied on individual impact models, ignoring uncertainty in crop model and biome model projections. Here, we propose a probabilistic decision framework that allows for an evaluation of agricultural management and mitigation options in a multi-impact-model setting. Based on simulations generated within the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), we outline how cross-sectorally consistent multi-model impact simulations could be used to generate the information required for robust decision making. Using an illustrative future land use pattern, we discuss the trade-off between potential gains in crop production and associated losses in natural carbon sinks in the new multiple crop-and biome-model setting. In addition, crop and water model simulations are combined to explore irrigation increases as one possible measure of agricultural intensification that could limit the expansion of cropland required in response to climate change and growing food demand. This example shows that current impact model uncertainties pose an important challenge to long-term mitigation planning and must not be ignored in long-term strategic decision making.}, language = {en} }