Institut für Tropische Agrarwissenschaften (Hans-Ruthenberg-Institut)

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How much to cut? Finding an optimal thinning intensity of encroaching woody species for the herbaceous community in an East African savanna
(2025) Abate, Teshome; Abebe, Tesfaye; Treydte, Anna
Globally, bush encroachment poses a great threat to the conservation of biodiversity and rangeland productivity. However, control methods of encroaching woody species have rarely been experimentally quantified. We assessed the impact of tree thinning intensities on tree mortality, and the herbaceous community in Borana rangelands, an Ethiopian savannah ecosystem. At two 1.4 ha areas of mono-specific Vachellia drepanolobium stands, we set up 20 m x 10 m experimental plots with four tree-thinning treatments (0%, 33%, 67%, and 100% tree removal), with three replications in a randomized complete block design (RCBD) across two sites. The 0% plot was left uncleared and used as control. Over two growing periods, we monitored resulting tree mortality, coppicing, seedling mortality, and recruitment as well as herbaceous layer attributes (diversity, biomass) and the rangeland conditions. Tree thinning intensity significantly increased abundance of the dominant desirable grass species. Total herbaceous and grass species richness, diversity and biomass were significantly improved under high (100%) and moderate (67%) tree removal intensity. We conclude that tree thinning at moderate intensity (67%) was most effective in enhancing mortality of encroached trees, and improving grass diversity, and herbaceous biomass. We stress that effective tree thinning requires post-thinning management and repeated bush control measures. Our findings contribute to development of recommendations on controlling bush encroachment, species restoration, and rangeland productivity in Ethiopian rangelands.
Causal machine learning methods for understanding land use and land cover change
(2026) Eigenbrod, F.; Alexander, Peter; Apfel, Nicolas; Athanasiadis, Ioannis N.; Berger, Thomas; Bullock, James M.; Duveiller, Gregory; Equihua, Julian; Menezes, Isaura; Moreira, Rodrigo; Paudel, Dilli; Sitokonstantinou, Vasileios; Reichstein, Markus; Willcock, Simon; Woodman, Tamsin; Eigenbrod, F.; School of Geography and Environmental Science, University of Southampton, SSO17 1BJ, Southampton, UK; Alexander, Peter; School of Geosciences, University of Edinburgh, EH9 3JW, Edinburgh, UK; Apfel, Nicolas; Department of Economics, University of Innsbruck, 6020, Innsbruck, Austria; Athanasiadis, Ioannis N.; Artificial Intelligence, Wageningen University and Research, Wageningen, The Netherlands; Berger, Thomas; Department of Land Use Economics, University of Hohenheim, 70599, Stuttgart, Germany; Bullock, James M.; UK Centre for Ecology & Hydrology, OX10 8BB, Wallingford, UK; Duveiller, Gregory; Max Planck Institute for Biogeochemistry, 07745, Jena, Germany; Equihua, Julian; Department of Computational Landscape Ecology, Helmholtz Centre for Environmental Research (UFZ), 04318, Leipzig, Germany; Menezes, Isaura; Artificial Intelligence, Wageningen University and Research, Wageningen, The Netherlands; Moreira, Rodrigo; Environmental Sciences Graduate Program, Federal University of Rondônia, 76900-726, Ji-Paraná, RO, Brazil; Paudel, Dilli; Artificial Intelligence, Wageningen University and Research, Wageningen, The Netherlands; Sitokonstantinou, Vasileios; Image Processing Laboratory, Universitat de València, Paterna, 46980, València, Spain; Reichstein, Markus; Max Planck Institute for Biogeochemistry, 07745, Jena, Germany; Willcock, Simon; School of Environmental and Natural Sciences, Bangor University, Bangor, LL57 2DG, Gwynedd, UK; Woodman, Tamsin; School of Geosciences, University of Edinburgh, EH9 3JW, Edinburgh, UK
Context: Understanding the roles of different drivers in land use and land cover change (LULCC) is a critical research challenge. However, as LULCC is the result of complex, socio-ecological processes and is highly context dependent, achieving such understanding is difficult. This is particularly true for causal modelling approaches that are critical for effective policy formulation. Causal machine learning (ML) methods could help address this challenge, but are as yet poorly understood or applied by the LULCC community. Objectives: To provide an accessible introduction to the state of the art for causal ML methods, their limitations, and their potential applications understanding LULCC. Methods: We conducted two workshops where we identified the most promising ML methods for increasing understanding of LULCC dynamics. Results: We provide a brief overview of the challenges to causal modelling of LULCC, including a simple example, and the most relevant causal ML approaches for addressing these challenges, as well as their limitations. Conclusions: Causal ML methods hold considerable promise for improving causal modelling of LULCC. However, the complexity of LULCC dynamics mean that such methods must be combined with domain understanding and qualitative insights for effective policy design.
Digital innovations and institutional barriers in agricultural input subsidy programmes in sub‐Saharan Africa: evidence from Nigeria
(2026) Adetoyinbo, Ayobami; Gupta, Saurabh; Okoruwa, Victor; Adetoyinbo, Ayobami; Department of Agricultural Economics, Agrifood Chain Management, Humboldt Universität zu Berlin, Berlin, Germany; Gupta, Saurabh; Centre for Development Policy and Management (CDPM), Indian Institute of Management, Udaipur (IIMU), Udaipur, India; Okoruwa, Victor; Department of Agricultural Economics, University of Ibadan, Ibadan, Nigeria
Motivation: Agricultural input subsidy programmes are crucial for improving agricultural productivity in sub‐Saharan Africa (SSA). However, there is little empirical evidence on how second‐generation input subsidy programmes (SISPs) based on information and communication technology (ICT) are implemented and the institutional challenges that undermine their effectiveness. Purpose: This article assesses the implementation of ICT‐based SISPs and their challenges in SSA using the Nigerian e‐wallet input subsidy programme as a case study. We draw on a conceptual framework that integrates the national innovation system (NIS), contingency theory, and new institutional economics. Approach and methods: We analysed expert interviews and participatory qualitative data from Process Net‐Maps and focus group discussions (FGDs) using content and Process Net‐Map analyses. Findings: The results show that over 20 public, private and community actors were involved in implementing the e‐wallet SISP across five stages. The programme increased private‐sector participation, reduced corruption, improved recipient targeting, and speeded up input delivery compared to first‐generation input programmes. However, weak institutional arrangements (such as poor funding, restricted institutional collaborations, and stakeholder capability gaps) undermined the innovation aspect of the e‐wallet SISP. The programme also faced five main challenges: policy inconsistency, poor information flow and weak reporting, moral hazards such as “round‐tripping,” input leakage and diversion, and elite capture. The study concludes that institutional constraints, rigid organizational structures, and a narrow focus on solving first‐generation programme challenges limited the ability of actors to adapt to new and evolving challenges. Policy implications: Effective SISPs and input policies require supportive institutional environments that allow actors from all sectors to function effectively. Programmes should thus be designed and managed with flexible and organic structures that foster collaboration among private, public, and community stakeholders. Continuous, stage‐specific evaluations and smart governance tools, such as real‐time mobile data collection and buy‐back initiatives, can strengthen monitoring, input tracking, accountability, and input use incentives.
Identifying governance challenges in scaling biofortification programs and the potential of training: a case study of Uganda
(2025) Alioma, Richard; Zeller, Manfred; Birner, Regina; Bosch, Christine; Muayahoto, Bho; Zeller, Manfred; Department of Rural Development Theory and Policy, Hohenheim University, Stuttgart, Germany; Birner, Regina; Department of Social and Institutional Change in Agricultural Development, Hohenheim University, Stuttgart, Germany; Bosch, Christine; Department of Social and Institutional Change in Agricultural Development, Hohenheim University, Stuttgart, Germany; Muayahoto, Bho; HarvestPlus, International Food Policy Research Institute, Washington, DC, United States
Introduction: Biofortification initiatives can significantly help reduce micronutrient deficiencies in developing countries. However, when hidden hunger affects a large segment of the population, large-scale implementation is necessary to achieve the desired results. We aimed to identify governance challenges in biofortification, and potential remedies based on a conceptual framework that considers low demand and the invisible nature of micronutrient traits in crops. Methods: Using process net maps and quantitative methods, this paper explores how farmer training can address governance issues. Results: Results show that, in addition to common agricultural marketing issues, sweet potato vine multipliers struggle with vine supply, value chain actors adulterate iron beans, and consumers are hesitant to pay higher prices for biofortified crops. These problems may result from information asymmetry, merit goods, collective action issues, and free riding. Furthermore, training had little impact on reducing the governance challenge arising from information asymmetry. Discussion/conclusion: One of the key solutions was investing in subsidies to increase production and raise awareness of the importance of nutritious foods. With governance problems, there is a need to take them into consideration when planning and expanding biofortification programs.
Evaluating the protein value of fresh tropical forage grasses and forage legumes using in vitro and chemical fractionation methods
(2021) Salazar-Cubillas, Khaterine C.; Dickhöfer, Uta
The objectives of the present study were (1) to assess the adequacy of the in vitro and chemical methods to predict post-ruminal crude protein supply (PRCP) from fresh tropical forage, and (2) to identify PRCP supply predictors. Twenty-three fresh forage grasses and 15 forage legumes commonly used in domestic cattle feeding in the tropics and subtropics were incubated in the rumen of cows to determine ruminal crude protein (CP) degradation. The PRCP supply was calculated from in situ rumen-undegraded CP and in vitro organic matter digestibility (i.e., reference method), from ammonia-nitrogen release during in vitro incubation (i.e., in vitro method), and from the concentrations of chemical CP fractions (i.e., chemical method). The adequacy was evaluated using error-index and dimensionless parameters, and stepwise regression was used to select PRCP predictors. Adequacy ranged from poor to moderate (0.53 to 0.74) for the in vitro method being lower for forage legumes at a slow rumen passage rate (0.20), and even poorer (0.02 to 0.13) for the chemical method. Hence, the in vitro method can estimate PRCP supply in tropical forages with moderate to high but not with slow passage rates. Equations developed in the present study appear to predict PRCP supply with reasonable adequacy.
Effect of irrigation canal conveyance efficiency enhancement on crop productivity under climate change in Nepal
(2024) Basukala, Amit Kumar; Eschenbach, Annette; Rasche, Livia
Nepal is expanding its irrigation facilities as an adaptive measure to climate change; however, the current canal conveyance efficiency (CCE) is low with significant water losses. In this study, we assess the potential impact of increasing CCE on the productivity of rice, maize, and wheat under different climate change scenarios (SSP1-2.6, SSP3-7.0, and SSP5-8.5), utilizing three bias-adjusted general circulation models. The study simulates potential yields at ecoregion levels for two periods: near future (2023 to 2050) and end-century (2075 to 2100). Management scenarios include the following: (1) business as usual, (2) CCE at 30%, (3) CCE at 50%, and (4) CCE at 70%. The results indicate that increasing CCE to 30%, coupled with expanded irrigated areas and adjusted fertilization rates, could boost yields by three tons per hectare across all three crops at the national level. Further increasing CCE to 50% could yield additional increases of up to 0.6 t/ha of maize and 1.2 t/ha of rice in the terai region. A CCE of 70% results in further increases of up to 2.1 t/ha of rice and 1.2 t/ha of maize. The benefits of improved CCE vary by location, with the subtropical terai region experiencing the most and the mountain regions showing the least. We conclude that there is potential to increase yields by increasing CCE to 70% in the terai region, 50% in the hill region, and 30% in the mountains. Wheat appears to benefit the least from improved CCE. This work highlights efficient irrigation as a reliable adaptive measure for future climate change in Nepal.
Unveiling the plant-associated microbiome responses and nitrification inhibition aspects of perennial intermediate wheatgrass (Thinopyrum intermedium)
(2025) Issifu, Sulemana; Rasche, Frank
Perennialization of agriculture has recently garnered attention as a nature-based solution (NBS) to complement predominantly annual cropping systems, offering a pathway toward sustainable agriculture and enhanced protection of agroecosystems. In this regard, the perennial intermediate wheatgrass, Thinopyrum intermedium, trade name Kernza®, has been proposed as a model plant for achieving perennialization of cereal cropping systems. Kernza® provides a broad range of ecosystem services, including enhanced carbon sequestration, enhanced biodiversity, and regulation of the nitrogen (N) cycle. Some studies reported regulated nitrification in Kernza® fields through reduced N2O emissions, low N leaching, and high legacy N. These traits indicate a plant-exerted control of nitrification through the secretion of bioactive metabolites, a concept known as biological nitrification inhibition (BNI). However, no study had investigated the mechanism behind these BNI traits of Kernza®. Relatedly, existing BNI studies have largely been confined to the identification and testing of single and novel metabolites. Moreover, while some studies have reported the ability of Kernza® to stimulate microbial activity and enhance microbial diversity, there is currently no study in a European context on the potential influence of Kernza® on the rhizosphere microbiome. Thus, this doctoral study aimed to fill these knowledge gaps. The first study used a metabolome fingerprinting approach to profile the metabolome of the Kernza® biomass collected from the field and root exudates collected under N sources (ammonium (NH4+) versus nitrate (NO3-)) in a hydroponic system. Multiple nitrification inhibitors, including several phenolic metabolites, were identified in higher quantities in the biomass of Kernza® than in annual wheat. These metabolites were also concurrently exuded in higher quantities by the roots of Kernza® under NH4+-N source than NO3--N source. Bioassays involving multiple ammonia-oxidising bacteria and archaea (AOB and AOA) confirmed the antimicrobial properties of crude root exudates of Kernza®, as well as individual metabolites such as caffeic acid, vanillic acid, vanillin, and phenylalanine. Soil incubation experiments further demonstrated the nitrification inhibition potential of all tested metabolites, except phenylalanine. This study presents the initial evidence elucidating the mechanisms by which Kernza® regulates nitrification and clarifies the function of Kernza’s® metabolome in mediating nitrification inhibition. In the second study, a pairwise combinatorial approach was employed to assess the interactions among biochemically distinct metabolites co-exuded by Kernza® – caffeic acid, vanillic acid, vanillin, and phenylalanine – against multiple ammonia-oxidisers and soil nitrification. It was found that the metabolites interacted both synergistically and antagonistically against the test strains and soil nitrification, with antagonism being the most predominant interaction among the metabolites. Caffeic acid exhibited single agent dominance (SAD), dominating all other metabolites in all combinations. Furthermore, nitrifiers responded differentially to the metabolites – affirming that nitrifiers are differentially sensitive to inhibitors. Both individual and paired metabolites inhibited the growth of multiple AOB and AOA, as well as soil nitrification – suggesting that both synergism and antagonism did not impair the inhibitory potentials of the metabolites. This evidence suggests that biochemically distinct metabolites exuded by Kernza® and other BNI-positive plants may be interacting in diverse ways in the rhizosphere to suppress nitrification. The third study assessed the impact of Kernza®-induced perennialization on rhizomicrobiome and root endophytes in comparison to annual wheat under an agroclimatic gradient (Sweden, France, and Belgium). The results suggest pronounced similarities in the rhizobacterial composition of Kernza® and annual wheat, with no significant difference in the alpha diversity of their rhizomicrobiome. Beta diversity analysis revealed that factors such as country (agroclimatic conditions), sampling depth (spatial), and year (temporal) rather exerted greater influence than crop type. Notwithstanding, Kernza® promoted the stability of the rhizomicrobiome than annual wheat based on year-on-year comparison – suggesting that perennialization has the ability to protect rhizomicrobiome from ecological perturbation. Moreover, Kernza® recruited and internalised a higher proportion of the rhizosphere microbiome into its root tissues compared to annual wheat, indicating a potential role of crop-associated microbiomes in the lifecycle of Kernza®. Furthermore, an environment-wide comparison with agroecologically relevant database revealed that Kernza®, compared to annual wheat, harboured a significant proportion of rhizobacterial taxa associated with the rhizosphere and grassland ecosystems – supporting the notion that Kernza® shares ecological characteristics with natural grasslands. This study adds to the growing body of knowledge on the rhizosphere ecology of Kernza® and provides further evidence for the ecosystem service potential of Kernza®.
Coffee berry borer control, but not coffee yield, is mediated by non-additive interaction between birds and ants across different cultivation systems
(2026) Cardona Tejada, Damaris A.; Parra, Juan L.; Grass, Ingo; Schurr, Frank M.
Coffee is one of the most traded tropical crops, cultivated in some of the most biodiverse regions on the planet. Coffee production can be seriously reduced by the coffee berry borer (CBB), a specialized beetle that feeds on the endosperm of coffee berries. Given the CBB's economic relevance, coffee-producing countries have developed extensive Integrated Pest Management programs. Nonetheless, most of these programs fail to incorporate CBB control by natural enemies such as birds and ants. While the effects of birds and ants on CBB suppression have been demonstrated to be positive when studied in isolation, their interactive effects have been little studied. To better understand the effects of the trophic interaction between birds and ants on CBB control, we conducted a full-factorial block experiment excluding birds and ants from coffee shrubs. We distributed 49 experimental blocks across three different coffee systems in a Colombian landscape: sun-exposed coffee, coffee-plantain intercropping, and shade coffee. We found birds to be key control agents of CBB: in the presence of ants, bird exclusion increased CBB infestation by 36 %. However, in the absence of ants, birds had little effect on CBB infestation, demonstrating that the effects of birds and ants were non-additive. This suggests that birds control CBB through a trophic cascade mediated by ants. We also found that the effects of exclusions were modified by the cultivation system, with the shade coffee system consistently reducing CBB infestation. Our experiment demonstrates that crop diversification is an effective measure for integrating local enemies into IPM strategies. Nonetheless, we acknowledge that trophic interactions are highly complex and exhibit a context-dependency that can result in the suppression of biological pest control. Therefore, we recommend conducting future analysis on evaluating the effects of predator´s community composition to encourage the development of IPM programs that leverage biodiversity in agroecosystems.
Complementary effects of pollination and biocontrol services enable ecological intensification in macadamia orchards
(2024) Anders, Mina; Westphal, Catrin; Linden, Valerie M. G.; Weier, Sina; Taylor, Peter J.; Grass, Ingo
In many crops, both pollination and biocontrol determine crop yield, whereby the relative importance of the two ecosystem services can be moderated by the landscape context. However, additive and interactive effects of pollination and biocontrol in different landscape contexts are still poorly understood. We examined both ecosystem services in South African macadamia orchards. Combining observations and experiments, we disentangled their relative additive and interactive effects on crop production with variation in orchard design and landscape context (i.e., cover of natural habitat and altitude). Insect pollination increased the nut set on average by 280% (initial nut set) and 525% (final nut set), while biocontrol provided by bats and birds reduced the insect damage on average by 40%. Pollination services increased in orchards where macadamia tree rows were positioned perpendicular to orchard edges facing natural habitat. Biocontrol services decreased with elevation. Pest damage was reduced by higher cover of natural habitat at landscape scale but increased with elevation. Pollination and biocontrol are both important ecosystem services and complementary in providing high macadamia crop yield. Smart orchard design and the retention of natural habitat can simultaneously enhance both services. Conjoint management of ecosystem services can thus enable the ecological intensification of agricultural production.
What will the future bring? – Socio-economic challenges to herder households in the Great Gobi B strictly protected area in Mongolia
(2024) Michler, Lena M.; Kaczensky, Petra; Batsukh, Daginnas; Treydte, Anna C.
Nomadic pastoralism is still practiced by around one-third of the Mongolian population. Recent socio-economic constraints have challenged pastoral livelihoods and rising livestock numbers threaten overall rangeland health and biodiversity conservation. In the Mongolian Gobi, herder households fully depend on livestock production but little is known about their livelihood trends and potential compatibility with protected area goals. We combined interview data in the Great Gobi B strictly protected area (SPA) with secondary data on regional and national herder households to determine the importance of social networks, willingness to continue a herding lifestyle, and degree of involvement in protected area (PA) management. Our descriptive data confirm that herding is no longer centred on a subsistence lifestyle but rather around cashmere production. Contrary to sustainability goals, especially in protected areas, herder households continue to increase livestock numbers in response to high expenditures in the economic reality of a market economy. We conclude that herders in the Great Gobi B SPA are reaching neither socio-economically nor ecologically sustainable livestock numbers which challenge herders’ livelihoods and PA management alike. We recommend enhancing communication between the PA management and the herding community and increasing participatory conservation activities. National strategies are needed to resolve the current dilemma of increasing livestock numbers to meet livelihood demands and the growing threat to rangeland health.
Correction to: Monitoring soil carbon in smallholder carbon projects: insights from Kenya
(2024) Okoli, Adaugo O.; Birkenberg, Athena
Nomadic by nature – adaptation strategies to ecological and socio-economic change among mongolian herders in the Dzungarian Gobi
(2025) Michler, Lena Maria; Treydte, Anna C.
Worldwide, pastoralism is the most common land use form practiced on extensive rangelands unsuitable for high-yielding agricultural production. For nomadic pastoralists, mobility is a key strategy since centuries to minimize grazing pressure on rangelands while providing nutritious forage resources to their livestock on pastures with high spatial-temporal resource variability. Herder mobility drastically declined in recent years due to changing socio-economic conditions, growing livestock numbers and climate change threating both ecological and socio-economic resilience of pastures and herding communities. In Mongolia, nomadic pastoralism is still practiced by one-third of the population. The country is sparsely populated and around 80% of the land is used for extensive livestock husbandry. While nomadic pastoralism was practiced on a subsistence level for centuries Mongolian herd-ers are nowadays living to the rules of a market economy with cashmere as most important cash crop. As a former satellite state of the Soviet Union, Mongolia initiated a transition to a market economy leading to a privatization of the market following the collapse of the USSR in 1991. Coupled with the international growing demand for cashmere, livestock numbers peaked at 70 million livestock heads in 2019. In combination with climate change, this may have lead to as much as 77% of Mongolia’s land now being considered degraded to a certain extent. My study focused on the Dzungarian Gobi and the rangelands within and around the Great Gobi B Strictly Protected Area (SPA) in south-western Mongolia. This key biodiversity area is home to several threatened and endangered wildlife and plant species such as the Przewalski’s horse (Equus ferus przewalskii), the Asiatic wild ass (Equus hemionus), and the Gobi desert plant Saxaul (Haloxylon ammodendron). The habitat is shared by nomadic herders and their livestock (goats, sheep, cows, horses and camels) who seasonally use the pastures within the limited use zone and buffer zone of the Great Gobi B SPA. Rangelands are considered being important social-ecological systems (SES). Therefore, I applied an integrative data analysis framework in my study, combining quantitative environmen-tal data with both quantitative and qualitative socio-economic information. Achieving a deeper understanding of the mobility patterns of nomadic herders and the effects of grazing on Gobi pastures, I collected Global Positioning System (GPS) tracking data of 19 small livestock herds over 20 months. Mobility and flexibility emerged as important adaptive strategies for herder households in the Dzungarian Gobi. Herders in the Dzungarian Gobi adjust their mobility patterns, camp selection, and livestock grazing strategies in response to the spatio-temporal availability of plant biomass, reflecting their adaptation to fluctuating resource availability. Herders changed their camp locations on average 9 times per year, covering a max-imum distance between winter camps in the Gobi plains and summer camps in the Altai moun-tains of 70-123 km. Small livestock spent more than half of the day within a radius of 100 m from camp and livestock use intensity decreased steeply with distance from camp. Available plant biomass and season best explained camp use duration. Daily walking distance and maximum distance from camp increased with camp use duration. Pasture time increased with in-creasing plant biomass and rising temperatures. I combined the GPS data with remotely-sensed environmental and climate data, and ground-based vegetation characteristics. Further, I determined herder preferences for camp selection in different plant communities based on focus group discussion data, and assessed the use and nutrient contents of the most important plant communities. In addition, I analysed plant species richness, vegetation cover, and plant biomass within different grazing radii around herder camps. Herders mainly selected their camp locations in Stipa spp. plant communities with high-est nutritional value. I found little evidence for a corresponding grazing gradient in plant species richness, plant biomass, and cover on the Gobi plains. Understanding the importance of altitudinal migration, I compared climatic conditions along the elevation gradient and determined seasonal body weight changes of goats and sheep. Lower summer temperatures and higher precipitation in the Altai mountains, resulted in higher productivity on summer pastures. Body weight of sheep and goats was slightly higher than the Mongolian average and body mass loss in winter was lower than in other parts of Mongolia. Further, I conducted semi-structured interviews with 125 herder households, three focus group discussions, and two expert interviews with PA rangers, to better understand the socio-economic challenges of herder households, and the interaction of protected area (PA) management and herder households in the Great Gobi B SPA. I combined interview data with secondary data on regional and national herder households to determine the importance of social networks, willingness to continue a herding lifestyle, and degree of involvement in PA management. My descriptive data confirmed that herding is no longer centred on a subsistence lifestyle but rather around cashmere production. Contrary to sustainability goals, especially in protected areas, herder households continue to increase livestock numbers in response to high expenditures in the economic reality of a market economy. I conclude that herders in the Great Gobi B SPA are reaching neither socio-economically nor ecologically sustainable livestock numbers which challenge herders’ livelihoods and PA management alike. Fostering cooperation and communication between herder households in the PA management, I tested paper diaries and small digital cameras as a tool to involve livestock herders as community-based rangers in the Great Gobi B SPA. I report the results of one herder who collected wildlife data over seven months as an example to show that his frequent wildlife sightings provide complementary information to data collected by rangers or scientists. Rising livestock numbers, changing socio-economics, and climate change threaten pasture resources and the resilience of ecosystems and livelihoods dependent on these resources. This thesis provides an overview of Mongolian herders' adaption strategies to ecological and socio-economic change in the Dzungarian Gobi. Although there is only limited evidence of pasture degradation yet, high mobility and flexible pasture use combined with altitudinal migration is still a crucial practice in this system and should be fostered by policy-makers. Considering the effects of climate change and the socio-economic demands on herder households to raise live-stock numbers, efficient pasture management is essential. Long-term environmental evaluations are required both inside and outside the Great Gobi B SPA, to identify changes in pasture eco-systems. Frequent livestock population monitoring and control measures are necessary to avoid overusing pasture resources and competition with wildlife, endangering the conservation of biodiversity and the livelihoods of herders. Through participatory activities, the Great Gobi B SPA management can involve local herder communities in conservation to enhance their understanding and improve communication. While herders in the Dzungarian Gobi have adapted to current ecological and socio-economic changes, it is a national responsibility to supporting herding communities by ensuring mobility, access to markets and social services, and create opportunities for economic diversification.
Design and development of an accessible open-source augmented reality learning authoring tool for applications in agroecological settings
(2024) Shidende, Deogratias; Treydte, Anna
Augmented Reality (AR) has emerged as a transformative educational technology, offering immersive, multisensory learning experiences that enhance engagement, conceptual understanding, and contextualization. In agroecology, where students must grasp complex ecological interactions and context-dependent knowledge, AR can bridge the gap between classroom instruction and field-based learning. However, the creation of AR content remains largely inaccessible to many educators in higher learning institutions (HLIs), particularly those without programming skills and individuals with disabilities such as the deaf and hard of hearing (DHH), and the blind and low vision (BLV). This dissertation addresses the central question: How can an accessible AR learning authoring tool enable non-technical educators and users with disabilities to create AR learning experiences for agroecology education in HLIs? To address this question, the study employed a design-based research (DBR) methodology, integrating Agile Scrum for iterative, inclusive tool development. Seven research questions (RQ1–RQ7) guided the investigation. First, a document-based analysis (RQ1) compared open-source software licenses (OSLs) to determine their suitability for academic–industry collaboration. Permissive licenses (e.g., MIT, BSD) were found to offer more flexibility in code reuse and integration, thereby promoting long-term project sustainability, although they require supplementary legal mechanisms to ensure reciprocity. Next, functional and non-functional software requirements (RQ2) were elicited through stakeholder workshops, interviews, surveys, and accessibility evaluations. These requirements informed the selection and redesign of MirageXR, an open-source AR platform. Key accessibility features were specified for DHH users, such as customizable captioning of audio augmentations, and for BLV users, such as voice navigation and spatial audio cues. These enhancements underscored the dual instructional and assistive roles of AR tools. In response to RQ3, a modular, component-based software architecture was designed using the C4 model. This enabled seamless integration of external services (e.g., 3D object repositories, learning management systems, and automatic speech recognition) and ensured that features could be added or updated without disrupting system stability. This modularity was essential given the evolving nature of AR technologies. The design and implementation phases (RQ4 & RQ5) employed participatory iterative prototyping with user feedback throughout the development process. Accessibility features were integrated into image, audio, and video augmentations, with functionalities such as caption editing, playback speed control, and 3D spatial positioning. These solutions directly addressed gaps in existing AR authoring tools, particularly for DHH and BLV users. The sixth research question (RQ6) investigated usability and applicability through an AR creation workshop involving 24 agroecology educators. Findings revealed that although participants initially encountered difficulties, they gained proficiency over time. UMUX scores showed a correlation between AR experience and perceived usefulness. Participants highlighted AR's potential to visualize complex concepts and engage students in experiential learning. However, limitations in 3D content availability and customization highlighted the need for integrated 3D content creation and editing tools specifically tailored to agroecology. To answer RQ7, the study conducted a systematic literature review of 60 studies to identify current accessibility evaluation methods in AR. Most evaluations employed task-based scenarios, utilizing metrics such as time on task, error rate, and user satisfaction. The study's own evaluation validated that DHH users could independently author AR content using the developed tool. In contrast, BLV users could navigate the authoring functionalities but were unable to fully author AR content, indicating that further design improvements and assistive functionalities are required for full inclusion. Methodologically, this study contributes a novel integration of DBR and Agile Scrum for inclusive educational technology design. This hybrid framework facilitated rapid prototyping, iterative refinement, and participatory co-design, and is recommended for broader application in accessibility-focused educational innovation. Future research should document and validate this methodological approach across additional contexts and user groups. The study makes the following contributions: (1) provision of an open-source, extensible AR authoring interfaces and codebase for public use; (2) improved AR accessibility for AR for DHH and BLV users; (3) development of modular architectural and algorithmic solutions to enable multimodal accessibility; (4) empirical validation of AR’s pedagogical value in agroecology education; and (5) identification of optimal open-source licensing models for collaborative educational software development. In sum, the findings demonstrate that an accessible, open-source AR authoring tool can empower diverse educators, including those with disabilities, to create inclusive and contextually relevant learning experiences. The research affirms the importance of universal design, participatory development, and modularity in educational technology design and concludes with strategic recommendations: integrating AI-assisted 3D content generation, expanding accessibility to additional user groups, and establishing communities of practice to support sustainable AR content development in agroecology.
Influence of climate-smart technologies on the success of livestock donation programs for smallholder farmers in Rwanda
(2024) Kandulu, John M.; Zuo, Alec; Wheeler, Sarah; Dusingizimana, Theogene; Chagunda, Mizeck G. G.
Climate change threatens the livelihoods of Sub-Saharan African farmers through increased droughts. Livestock donation programs offer a potential solution, but their effectiveness under climate stress remains unclear. This study assesses the economic viability of integrating climate-smart technologies (cowsheds and biogas plants) into these programs in Rwanda. Using a stochastic benefit–cost analysis from the beneficiary perspective, we evaluate the net gains for households receiving heifers compared to the current program. Our findings reveal that integrating climate-smart technologies significantly enhances economic viability. Households with cows and climate-smart technologies can possibly realise net benefits 3.5 times higher than the current program, with benefit–cost ratios reaching 5:1. Beyond economic benefits, adopting biogas reduces deforestation, greenhouse gas emissions, and respiratory illness risks. This study demonstrates that integrating climate-smart technologies into livestock donation programs can generate positive economic, environmental, and health benefits, leading to more resilient and sustainable smallholder systems. However, overcoming implementation challenges requires tailored policy packages addressing local barriers.
Monitoring soil carbon in smallholder carbon projects: insights from Kenya
(2024) Okoli, Adaugo O.; Birkenberg, Athena
Voluntary carbon market schemes facilitate funding for projects promoting sustainable land management practices to sequester carbon in natural sinks such as biomass and soil, while also supporting agricultural production. The effectiveness of VCM schemes relies on accurate measurement mechanisms that can directly attribute carbon accumulation to project activities. However, measuring carbon sequestration in soils has proven to be difficult and costly, especially in fragmented smallholdings predominant in global agriculture. The cost and accuracy limitations of current methods to monitor soil organic carbon (SOC) limit the participation of smallholder farmers in global carbon markets, where they could potentially be compensated for adopting sustainable farming practices that provide ecosystem benefits. This study evaluates nine different approaches for SOC accounting in smallholder agricultural projects. The approaches involve the use of proximal and remote sensing, along with process models. Our evaluation centres on stakeholder requirements for the Measurement, Reporting, and Verification system, using the criteria of accuracy, level of standardisation, costs, adoptability, and the advancement of community benefits. By analysing these criteria, we highlight opportunities and challenges associated with each approach, presenting suggestions to enhance their applicability for smallholder SOC accounting. The contextual foundation of the research is a case study on the Western Kenya Soil Carbon Project. Remote sensing shows promise in reducing costs for direct and modelling-based carbon measurement. While it is already being used in certain carbon market applications, transparency is vital for broader integration. This demands collaborative work and investment in infrastructure like spectral libraries and user-friendly tools. Balancing community benefits against the detached nature of remote techniques is essential. Enhancing information access aids farmers, boosting income through improved soil and crop productivity, even with remote monitoring. Handheld sensors can involve smallholders, given consistent protocols. Engaging the community in monitoring can cut project costs, enhance agricultural capabilities, and generate extra income.
Use of seasonal forecasts in smallholder agricultural decision-making in the Central Rift Valley of Ethiopia
(2025) Kayamo, Samuel Elias; Berger, Thomas
Smallholder farmers in Ethiopia’s Central Rift Valley face pronounced risks from climate variability and erratic rainfall, challenges that threaten agricultural productivity, food security, and rural livelihoods. Rising climate hazards have spurred the promotion of seasonal precipitation forecasts as a promising means of supporting adaptation, yet the translation of such information into tangible adaptive action depends on a complex interplay of local agro-ecological conditions, available adaptation strategies, and behavioral responses. This thesis provides a comprehensive, interdisciplinary investigation into the economic value, adoption dynamics, and policy implications of seasonal forecast information for smallholder farmers, integrating agent-based modelling, dynamic risk assessment, crop-growth simulation, and framed field experiments. A principal focus of the research is the evaluation of adaptive management strategies for smallholder farmers enabled by seasonal forecasts. Examined strategies include crop and cultivar selection in response to rainfall outlooks, optimized planting dates, forecast-driven fertilizer management, and flexible in-season adjustments (such as crop switching or tied ridging). Each option is rigorously evaluated using observational, experimental and simulated data. In assessing the practical impacts of integrating seasonal rainfall forecast information into smallholder agricultural decision making, the results of this thesis indicate that forecast-based cultivar selection has the potential to support more effective management strategies for farmers in Ethiopia’s Central Rift Valley. By enabling better alignment of cultivar choices with anticipated seasonal rainfall conditions, farmers can enhance the adaptive capacity of their management practices in the face of climate variability. While the observed financial gains under realistic forecast accuracy are modest, these findings highlight that forecast-based cultivar selection can serve as a valuable decision-support tool. However, realizing the full potential of this approach depends not only on improvements in forecast skill, but also on the availability of reliable evidence regarding cultivar performance under diverse weather conditions and on substantial changes to seed breeding and distribution systems. Only when forecast-matching cultivars are made available to farmers promptly can the benefits of high-accuracy seasonal rainfall forecasts be more fully achieved. In the subsequent analysis, this thesis applies a state-contingent embedded risk framework to systematically explore how the timing of smallholder management decisions—specifically crop choice, sowing date, tied-ridging, relay cropping, and fertilization—can be optimized in light of seasonal rainfall forecast information. Using multi-stage discrete stochastic programming, the study evaluates adaptive strategies at the whole-farm level by simulating crop yield responses to management choices across 2,400 possible weather trajectories. The results show that forecast-informed management decisions can improve farmer income, but the extent and consistency of these benefits vary across seasons. The findings further reveal that opportunities for in-season adjustment—rather than choices made solely at the start of the season—are especially critical for achieving positive results in response to forecast information. By evaluating the long-term impacts of forecast-based decision making at the whole-farm level in the Central Rift Valley, this study emphasizes the need for more tailored and effective communication and advisory services of seasonal rainfall forecasts. In addition, the analysis highlights the inherent unpredictability of agricultural outcomes under climate uncertainty and demonstrates the continuing importance of building empirical understanding of how management actions and varying weather conditions together shape farm performance. These insights suggest that policy interventions aimed at strengthening real-time advisory systems and supporting farmers’ capacity for flexible, adaptive management are essential for fully realizing the benefits of seasonal rainfall forecasting in smallholder agriculture. The third component of the thesis explores how smallholder farmers receive, interpret, and act upon seasonal precipitation forecasts, drawing on evidence from framed field experiments conducted in Ethiopia’s Central Rift Valley. The analysis demonstrates that neither improvements in forecast accuracy nor dissemination of information alone are sufficient to induce significant behavioral change among farmers. Adoption is most likely when seasonal precipitation forecasts are communicated repeatedly, presented in clear and actionable formats, and tailored to local realities through trusted channels. The results further indicate that factors such as farmers’ education levels, prior experience with seasonal forecasts, and regular engagement with extension services play a central role in facilitating effective use of such information. The findings highlight the potential of digital innovations, such as smartphone-based advisories and AI-supported tools, to improve the reach and personalization of seasonal precipitation forecasts, provided these solutions are developed through participatory and user-centered approaches. Overall, the study underscores the importance of aligning advisory services with both the informational and contextual needs of smallholder farmers in order to foster more effective and inclusive adaptation to climate variability. Overall, the results of this thesis emphasize that the benefits of seasonal rainfall forecasts can only be fully realized through an integrated approach. This requires the combination of advances in forecast technology, adaptive input systems, effective communication, and supportive policy environments. Comprehensive and locally tailored adaptation packages—linking seasonal rainfall forecast information to improved access to seed and inputs, credit, training, and extension services—emerge as the most effective strategy for strengthening resilience. Ultimately, by connecting quantitative modeling, empirical experimentation, and policy analysis, this thesis provides a robust foundation for scaling up inclusive, impactful advisory systems based on seasonal rainfall forecasts to better equip smallholder farmers for managing risks associated with increasing rainfall variability.
Production and use of forages from permanent pastures in grazing-based dairy cattle systems in Southwest Germany
(2024) Velasco Gutierez, Elizabeth; Dickhöfer, Uta
A steadily growing world population and its rising standard of living are putting pressure on agricultural systems to provide food of good quality while minimizing environmental impacts. As a result, traditional practices such as grazing are becoming more popular in dairy systems. Permanent grasslands cover 34 % of the agricultural area in the European Union (EU). Semi-natural grasslands (SNG) are defined as permanent grasslands formerly used for mowing or grazing that have not been substantially modified by agricultural practices. The federal State of Baden-Wuerttemberg in Germany has a great proportion of SNG compared to other federal States in the country. The use of forage on SNG in grazing-based dairy cattle systems has the potential to produce milk sustainably, by respecting the environment, closing nutrient cycles, and promoting animal welfare, while ensuring high-quality forage production. However, there is limited data on the performance and practical use of SNG in grazing-based dairy cattle systems. This doctoral thesis aims at characterizing, evaluating, and quantifying the forage on SNG in grazing-based dairy cattle systems in Southwest Germany focusing on (1) forage availability, (2) feed energy self-sufficiency, and (3) feed supplementation in on-farm approach To characterize grazing-based dairy cattle systems and evaluate the potential of SNG for grazing and milk production, semi-quantitative interviews were conducted on 27 farms in the summer of 2018. Above-ground forage biomass from pastures was harvested and analyzed for nutrient composition. Farms differed regarding land endowment and use, dairy herd size, and thus stocking rates. Farmers implemented rotational (n = 12), short-grass (n = 10), continuous (n = 3), or strip (n = 2) grazing systems with < 8 h (n = 4), 8-12 h (n = 14), and > 12 h (n = 9) of daily pasture access during the grazing season. During the summer of 2018, available pasture forage (kg dry matter (DM)/ha) ranged from only 122 to 1,208. Crude protein (CP) and metabolizable energy (ME) concentrations varied greatly with 85 to 282 g and 7.9 to 11.0 MJ/kg DM, respectively. Diet digestibility estimated from fecal CP content ranged from 59.2 to 72.2 g/100 g organic matter (OM). Some farms succeeded in maintaining milk yields constant despite the lack of rainfall in that year. To quantify the forage availability of SNG as well as the feed energy self-sufficiency in seven commercial organic dairy cattle farms in Southwest Germany during the grazing season of 2019 and 2020, exclusion cages were set up in dairy cattle paddocks. Pasture samples were collected inside and outside the exclusion cages every 30 to 65 d, and analyzed by near-infrared reflectance spectroscopy for DM, CP, neutral detergent fiber (NDF), acid detergent fiber (ADF), apparent total tract digestibility organic matter (dOM), and ME. The results showed that SNG have the potential to produce a forage biomass up to 10,959 kg DM/ha and a with concentrations of CP, NDF, ADF up to 232 g/kg DM, 395 g/kg DM, and 214 g/kg DM, respectively. The concentrations of dOM and ME were up to 771 g/kg OM and 10.7 MJ/kg DM, respectively. The potential of grazing on SNG for dairy milk production was not fully exploited, although on some farms and at some times during the grazing season, grazing on SNG provided 100 % of the energy requirements of lactating dairy cattle, while on other farms, grazing on SNG provided only 2.8 % of the energy requirements. The differences in milk production from grazing SNG observed between farms were mainly due to management factors such as stocking rate and feed supplementation, while environmental factors played a minor role. To evaluate the effects of feed supplementation in grazing-based dairy cattle systems, three feeding experiments were conducted to compare feed supplementation under grazing conditions of (1) grass hay versus fresh grass-clover mixtures, (2) grass hay before or after grazing, and (3) timing of concentrate supplementation on two organic commercial dairy cattle farms in Southwest Germany in two periods in 2019 and 2020. Experiment 1 showed that the dairy cattle supplemented with fresh grass-clover mixtures had lower fecal nitrogen (N) excretion compared to the dairy cattle supplemented with grass hay. Experiment 2 demonstrated that grass hay supplementation before grazing led to a decrease in pasture organic matter intake (OMI), while grass hay supplementation in the morning (i.e., hay AM) decreased fecal N excretion in dairy cattle. Experiment 3 showed that offering less concentrate to dairy cattle before grazing resulted in higher pasture OMI in period 1, but also higher N intake and, lower fecal N excretion. The results of the feeding experiments demonstrate that simple management practices, such as the timing of feed supplementation can influence individual N utilization. The results of this doctoral thesis demonstrated that forage of SNG has the potential to produce forage biomass, adequate nutrient content, and energy concentration even under dry conditions. To maximize the use of SNG for grazing, the dynamics between forage biomass and supplemented feed should be considered, to maximize the use of SNG. Grazing management decisions play an important role in the use of forage of SNG for grazing in dairy cattle systems. The present thesis provides insights into grazing-based dairy cattle systems and valuable information on on-farm conditions in Central Europe. Future studies should be carried out in other countries and regions to obtain a more comprehensive panorama of the potential of the forage on SNG for milk production.
Assessing impacts of crop area expansion and crop-livestock integration on ecosystem functions in African savannas using the coupled LUCIA and LIVSIM models
(2025) Gutai, Benjamin; Marohn, Carsten; Bateki, Christian Adjogo; Asch, Folkard
Large-scale land use change (LUC) of African Guinea savannas to crop fields is expected to cause negative impacts on ecosystem functions (ESF) and long term land productivity. The complex interactions of key processes in savannas evoked by LUC calls for a process-based modelling approach. We employed the dynamically coupled Land Use Change Impact Assessment (LUCIA) model and the Livestock Simulator (LIVSIM) which represent LUC impacts on soil processes, landscape-scale matter fluxes, seasonal grass and crop growth, and livestock nutrition, production and reproduction, depending on seasonal feed availability and quality on accessible pastures. For a rangeland in Borana, Ethiopia, two different LUC scenarios were evaluated in comparison to the baseline of traditional pasture-based land use. In the intensive LUC scenario 52% of grassland was converted into unfertilized maize fields, inaccessible for livestock. The integrated LUC scenario of the same grassland conversion rate allowed feeding maize straw and provided high-quality feed reserves from seasonally managed pastures. LUC in the intensive LUC scenario led to declining yields in the second year after conversion. Feed production on the remaining rangeland patches was insufficient for livestock nutrition, causing drops of herd body weight and herd size particularly in drought years. Resilience of herd performance to LUC was enhanced in the integrated LUC scenario when feeding maize straw and high-quality feed reserves. In both LUC scenarios, topsoil organic carbon storage decreased after ploughing shrub grassland for cultivation, and so did soil water storage capacity due to soil pore destruction. Soil erosion of less than one cm after 10 years occurred under cultivation. The simulation results indicated that the well validated model framework could predict impacts of LUC and simple crop-livestock integration on savanna ESFs, grass growth dynamics and livestock production during seasonal and inter-annual rainfall variation. This study lays the foundation for further land use scenario simulations to improve the understanding of benefits and risks caused by savanna grassland conversion.
Rainforest fragmentation decreases the robustness of plant‐frugivore interaction networks
(2025) Becker, David; Li, Wande; Gurung, Ashtha; Rodriguez Martinez, Eduardo; Rojas, Emmanuel; Rodríguez‐Herrera, Bernal; Vollstädt, Maximilian G. R.; Grass, Ingo; Hiller, Thomas
Tropical rainforests are biodiversity hotspots that provide a variety of ecosystem functions and services. Seed dispersal by fruit‐eating birds is an important ecosystem process in the regeneration of tropical rainforests, which is increasingly threatened by widespread deforestation. In particular, the expansion of agricultural land often leads to forest fragmentation, which can have a negative impact on the interactions between plants and frugivores and thus on seed dispersal. However, little is known about how forest fragmentation affects the structure and robustness of plant–frugivore interaction networks. Here, we examined the effects of forest fragmentation on species richness of frugivorous birds interacting with focal tree species, and the structure and robustness of plant–frugivore interaction networks in the tropical lowland forests of northern Costa Rica. Species richness of frugivorous birds at the forest edges increased with fragment size and forest cover in the surrounding landscape as well as with local fruit availability. Modularity and robustness of plant–frugivore networks increased with enhanced fragment size and forest cover, while network specialization (H2′) increased only with greater forest cover. Additionally, the three common tanager species ( Ramphocelus passerinii , Thraupis palmarum , and Thraupis episcopus ) were identified as key bird species for network functioning by promoting among‐module and within‐module connectivity. Conservation measures should therefore not only focus on threatened specialist species, but more on the key species that enhance network structure and consequently increase the robustness of these trophic interaction networks. Ultimately, our study demonstrates that tropical forest fragmentation simplifies network structure, making these interactions more vulnerable to anthropogenic disturbances.
Market potential for organic dairy and meat products from “calf-friendly” dairy farms across different consumer segments
(2025) Herrler, Mareike; Chagunda, Mizeck G. G.; Stroebele-Benschop, Nanette
As public criticism of the management of surplus dairy calves increases, new approaches are required to improve calf welfare to maintain the dairy industry’s license to produce. Little is known about consumers’ willingness to buy (WTB) organic dairy and meat products from farms that aim to improve the welfare of surplus dairy calves. This study aims to address this research gap by identifying potential target groups for assessing the market potential of these products in south-west Germany. For this purpose, an online survey was conducted among 922 participants in this region. Participants were presented with one of three scenarios describing different rearing systems for dairy calves that hold the potential to provide enhanced calf welfare in comparison to current dairy farming practices: Cow-calf contact, the use of dual-purpose breeds and on-farm slaughter. Factor and cluster analyses were performed to identify potential target groups for organic dairy and meat products from these “calf-friendly” rearing systems. The four clusters Conscious organic shoppers, Moderate sustainability advocates, The indifferent consumers and the Interested organic refusers were identified. The findings indicate that organic consumers who care about calf welfare and prioritize product quality and sustainability when buying food are a promising target group for products from “calf-friendly” organic dairy farms. Consumers’ WTB seems to depend more on their general attitudes and financial means than on the presented scenarios. By identifying a potential target group for these products, this study fills a research gap and may contribute to more effective and targeted marketing.

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