Institut für Tropische Agrarwissenschaften (Hans-Ruthenberg-Institut)

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Monitoring soil carbon in smallholder carbon projects: insights from Kenya
(2024) Okoli, Adaugo O.; Birkenberg, Athena; Okoli, Adaugo O.; Department of Social and Institutional Change in Agricultural Development, Hans-Ruthenberg-Institute of Agricultural Science in the Tropics, University of Hohenheim, Wollgrasweg 43, 70599, Stuttgart, Germany; Birkenberg, Athena; Department of Social and Institutional Change in Agricultural Development, Hans-Ruthenberg-Institute of Agricultural Science in the Tropics, University of Hohenheim, Wollgrasweg 43, 70599, Stuttgart, Germany
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; Dickhoefer, 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; Gutai, Benjamin; Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, Garbenstr. 13, 70599, Stuttgart, Germany; Marohn, Carsten; Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, Garbenstr. 13, 70599, Stuttgart, Germany; Bateki, Christian Adjogo; Section Animal Husbandry in the Tropics and Subtropics, University of Kassel and University of Göttingen, Steinstr. 19, 37213, Witzenhausen, Germany; Asch, Folkard; Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, Garbenstr. 13, 70599, Stuttgart, Germany
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; Becker, David; Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany; Li, Wande; Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany; Gurung, Ashtha; Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany; Rodriguez Martinez, Eduardo; Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany; Rojas, Emmanuel; Reserva Biológica Tirimbina, Heredia, Costa Rica; Rodríguez‐Herrera, Bernal; Escuela de Biología y Centro de Investigación en Biodiversidad y Ecología Tropical (CIBET), Universidad de Costa Rica, San José, Costa Rica; Vollstädt, Maximilian G. R.; Instituto Mediterráneo de Estudios Avanzados (CSIC‐UIB), Mallorca, Balearic Islands, Spain; Grass, Ingo; Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany; Hiller, Thomas; Ecology of Tropical Agricultural Systems, University of Hohenheim, Stuttgart, Germany
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.
Determining the footprint of breeding in the seed microbiome of a perennial cereal
(2024) Michl, Kristina; David, Christophe; Dumont, Benjamin; Mårtensson, Linda-Maria Dimitrova; Rasche, Frank; Berg, Gabriele; Cernava, Tomislav; Michl, Kristina; Institute of Environmental Biotechnology, Graz University of Technology, 8010, Graz, Austria; David, Christophe; Department of Agroecosystems, Environment and Production, ISARA, 23 rue Jean Baldassini, 69364, Lyon Cedex 07, France; Dumont, Benjamin; Plant Sciences Axis, Crop Science lab, ULiege - Gembloux Agro-Bio Tech, B- 5030, Gembloux, Belgium; Mårtensson, Linda-Maria Dimitrova; Department of Biosystems and Technology, Swedish University of Agricultural Sciences, P.O. Box 103, Lomma, Alnarp, Sweden; Rasche, Frank; Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute), University of Hohenheim, 70593, Stuttgart, Germany; Berg, Gabriele; Institute of Environmental Biotechnology, Graz University of Technology, 8010, Graz, Austria; Cernava, Tomislav; Institute of Environmental Biotechnology, Graz University of Technology, 8010, Graz, Austria
Background: Seed endophytes have a significant impact on plant health and fitness. They can be inherited and passed on to the next plant generation. However, the impact of breeding on their composition in seeds is less understood. Here, we studied the indigenous seed microbiome of a recently domesticated perennial grain crop (Intermediate wheatgrass, Thinopyrum intermedium L.) that promises great potential for harnessing microorganisms to enhance crop performance by a multiphasic approach, including amplicon and strain libraries, as well as molecular and physiological assays. Results: Intermediate wheatgrass seeds harvested from four field sites in Europe over three consecutive years were dominated by Proteobacteria (88%), followed by Firmicutes (10%). Pantoea was the most abundant genus and Pantoea agglomerans was identified as the only core taxon present in all samples. While bacterial diversity and species richness were similar across all accessions, the relative abundance varied especially in terms of low abundant and rare taxa. Seeds from four different breeding cycles (TLI C3, C5, C704, C801) showed significant differences in bacterial community composition and abundance. We found a decrease in the relative abundance of the functional genes nirK and nifH as well as a drop in bacterial diversity and richness. This was associated with a loss of amplicon sequence variants (ASVs) in Actinobacteria , Alphaproteobacteria , and Bacilli , which could be partially compensated in offspring seeds, which have been cultivated at a new site. Interestingly, only a subset assigned to potentially beneficial bacteria, e.g. Pantoea, Kosakonia , and Pseudomonas , was transmitted to the next plant generation or shared with offspring seeds. Conclusion: Overall, this study advances our understanding of the assembly and transmission of endophytic seed microorganisms in perennial intermediate wheatgrass and highlights the importance of considering the plant microbiome in future breeding programs.
Why are toilets not used? Using system effects modelling to understand stakeholder perceptions on the impacts and barriers to Taenia solium control in Eastern and Western Uganda
(2025) Ngwili, Nicholas; Ahimbisibwe, Salaviriuse; Sentamu, Derrick N.; Craven, Luke; Thomas, Lian F.; Roesel, Kristina; Ngwili, Nicholas; Health program, International Livestock Research Institute, Nairobi, Kenya; Ahimbisibwe, Salaviriuse; Health program, International Livestock Research Institute, Nairobi, Kenya; Sentamu, Derrick N.; Department of Public Health Pharmacology and Toxicology, Faculty of Veterinary Sciences, University of Nairobi, Nairobi, Kenya; Craven, Luke; Partnerships for Local Action and Community Empowerment, Melbourne, Australia; Thomas, Lian F.; Health program, International Livestock Research Institute, Nairobi, Kenya; Roesel, Kristina; Health program, International Livestock Research Institute, Nairobi, Kenya
Taenia solium taeniasis/cysticercosis in humans and pigs remains endemic to Uganda. Although, looking at the lifecycle of the parasite, the risk factors are well known, and many biomedical control options exist – no substantial progress has been made in the eradication of T. solium infections in Uganda to date. Contextual factors including socioeconomic, cultural and infrastructural factors, may influence the adoption of interventions. A community-based study using mixed methods and relying on system effects modelling approach was carried out between March and April 2021 in Kamuli district, Eastern Uganda, and Hoima district, Western Uganda. System effects modelling is a non-linear methodology that captures the varied nature of the unique, individually lived experiences and aggregates them to reflect what is experienced at a population level. The aim of the study was to capture individual stakeholder perceptions on the consequences of T. solium infections and barriers to practice known control options. Overall, 27 factors were identified by 192 participants as consequences of being infected with neurocysticercosis (NCC). For taeniasis, 35 factors were identified with 700 edges/connections made by the participants. Enlargement of stomach, weight loss, diarrhoea, weakness, and stunted growth were the most important consequences. Although porcine cysticercosis (PCC) seemed to be poorly understood by the participants, 14 factors were identified which included poor pig growth, loss of market for pig/pork, and poor pork quality. The study also identified important barriers hindering the adoption of control practices, including lack of knowledge on transmission, sociocultural factors, and resource constraints. For women, lack of knowledge on the mode of transmission and lack of a toilet in the compound ranked highly as important barriers with a weighted degree of 31 and 21, respectively, meaning they were identified by more participants unlike men who ranked lack of a toilet first with a weighted degree of 39, followed by lack of knowledge at 24. Different barriers are associated with the adoption of T. solium control practices among community members, stakeholders, and farmers. Despite efforts to address T. solium infections, misconceptions and limited understanding persist among stakeholders, particularly regarding NCC and its associated consequences. The system effects approach supports developing contextualized interventions to help in the control of the diseases associated with this parasite.
Complementary ecosystem services from multiple land uses highlight the importance of tropical mosaic landscapes
(2023) Raveloaritiana, Estelle; Wurz, Annemarie; Osen, Kristina; Soazafy, Marie Rolande; Grass, Ingo; Martin, Dominic Andreas; Bemamy, Claudine; Ranarijaona, Hery Lisy Tiana; Borgerson, Cortni; Kreft, Holger; Hölscher, Dirk; Rakouth, Bakolimalala; Tscharntke, Teja
Tropical agricultural landscapes often consist of a mosaic of different land uses, yet little is known about the spectrum of ecosystem service bundles and materials they provide to rural households. We interviewed 320 households on the different benefits received from prevalent land-use types in north-eastern Madagascar (old-growth forests, forest fragments, vanilla agroforests, woody fallows, herbaceous fallows, and rice paddies) in terms of ecosystem services and plant uses. Old-growth forests and forest fragments were reported as important for regulating services (e.g. water regulation), whilst fallow lands and vanilla agroforests as important for provisioning services (food, medicine, fodder). Households reported the usage of 285 plant species (56% non-endemics) and collected plants from woody fallows for varying purposes, whilst plants from forest fragments, predominantly endemics, were used for construction and weaving. Multiple land-use types are thus complementary for providing ecosystem services, with fallow lands being particularly important. Hence, balancing societal needs and conservation goals should be based on diversified and comprehensive land management.
Enhancing weed suppression in plants by artificial stress induction
(2025) Merkle, Michael; Petschenka, Georg; Belz, Regina; Gerhards, Roland
Various plant species from the Poaceae, Cannabaceae, and Brassicaceae families are used as cover crops to suppress weeds and volunteer crops through competition and allelopathy. This study examined the effects of artificially induced stress on the physiological processes, total phenolic content (TPC), and allelopathic potential of the plant species Avena strigosa, Cannabis sativa , and Sinapis alba at an early growth stage with the aim to increase their weed suppression abilities. Stress was induced at the 3–4 leaf stage in greenhouse-grown plants via harrowing, methyl jasmonate (MeJA) application, insect stress simulation, or a combination of insect stress and harrowing. Maximum quantum yield of photosystem II and shoot dry matter in the three plant species were only minimally or not affected a few days after treatment (DAT). Insect stress caused visible symptoms on treated leaves in all plants. The TPC in the shoot extracts of combined stress-treated C. sativa and insect-stressed S. alba was significantly higher by 1.7 and 1.9 times, respectively, five DAT compared to the shoot extracts from untreated control plants. Additionally, laboratory bioassays with aqueous shoot extracts from the untreated and treated plants were conducted to identify changes in allelopathic potential within the shoot tissues. The application of shoot extracts from MeJA-treated C. sativa and S. alba resulted in the lowest seed germination rates for the two weed species Alopecurus myosuroides and Stellaria media , as well as for the volunteer wheat Triticum aestivum , which were up to 65% lower 10 DAT compared to seeds treated with shoot extracts from non-stressed plants. However, the root-suppressing effect of the shoot extracts on weeds was not influenced by the stress treatments. This study reveals that artificial stress induction can be a suitable management strategy to enhance weed and volunteer cereal suppression in plants in an early growth stage but may vary between stress types and plant species, and requires further optimization and field testing.
Guidelines for improved quantification and reporting of carbon stocks and additional carbon storage in agroforestry systems
(2025) Cardinael, Rémi; Cadisch, Georg; Dupraz, Christian; Lojka, Bohdan; Oelbermann, Maren
The number of scientific publications related to biomass carbon or soil organic carbon under various land management practices has globally and dramatically increased during the last two decades, the same applies to the peer reviewed Agroforestry Systems journal. However, the quality of papers on carbon sequestration in agroforestry systems is very heterogeneous, and many studies do not fulfil simple requirements that would ensure the scientific value of these studies, resulting in high rates of rejections before and after review. The aim of this paper, co-authored by the Editor-in-Chief and Associate Editors of the Agroforestry Systems journal is to provide some basic guidelines to improve the quantification and reporting of carbon stocks and additional carbon storage in agroforestry systems, and to maximize manuscript acceptance. These guidelines are also of use for any other international peer-reviewed journal publishing studies on this topic. We also provide a checklist, for both authors and reviewers, of compulsory and recommended variables to be included before submission of an original study related to soil and/or biomass carbon stocks and sequestration in agroforestry systems.
Smallholder agricultural practices in Indonesia: information and communication technologies (ICTs) usage, extension agent performance, and the impact of interventions on technical efficiency
(2025) Dewi, Yovita Anggita; Zeller, Manfred
Indonesia’s agricultural sector—in particular including its smallholder farmers—remains the country’s economic backbone, as evidenced by its contribution to the gross domestic product (GDP). This role was further demonstrated during the Covid-19 crisis, when the sector supported resilience through labor absorption, where many urban laborers and small entrepreneurs lost their job and fled back to their home villages. Smallholder farmers in Indonesia grapple with a range of hurdles including technical limitations, social dynamics, economic pressures, and institutional constraints, which hinder their ability to boost productivity, increase output, and improve their incomes. There are pathways to enhance productivity such as encouraging the adoption of new technologies, improving farmers’ access to information, financial resources, and market insights, expanding the reach and impact of extension and advisory services (EAS), and addressing the gender disparities within agriculture. This dissertation focuses on the role of extension services as far as they seek to improve their effectiveness and their effects on selected challenges regarding agricultural extension of smallholder farmers in Indonesia. Therefore, this work focuses on: (i) leveraging the use of information and communication technologies (ICTs) among extension agents and farmers to broaden and improve access to information, enhance knowledge and skill, and foster gender inclusion; (ii) evaluating the effectiveness of extension agents based on their performance in fulfilling their responsibilities; and (iii) empirically assessing the impact of government initiatives on agricultural productivity, with a particular emphasis to access to extension services and the utilization of certified seed. This dissertation employs various econometric techniques to study each topic, such as multiple linear regression models, probit regression models, principal component analysis, stochastic metafrontier analysis, and endogenous switching regression models. Furthermore, this research employs both in-person data collection and online survey. As outlined in chapter three, the online survey method serves as a valuable alternative when direct fieldwork is not feasible. Beyond cross-sectional data, this dissertation also draws upon panel data focusing on rice smallholder farmers to analyze the impacts of agricultural interventions, as elaborated in chapter four. Chapter two explores how ICT is used by extension agents and smallholder farmers, focusing on digital content mismatch and the heterogeneity of ICT use to enhance the extension services. ICT is widely used to provide extension services, founded on the major hope that expanding such services will improve the quality and efficiency of agricultural services while also reducing the gender disparity in access to agricultural services. In this chapter, this dissertation explores the most commonly used ICT tools to provide agricultural extension services, their effectiveness in reaching farmers, and the gender gap in the use of such services in Indonesia. Unique agent-to-farmer matched data are used, gathered through a survey of farmers and extension agents. The data analysis reveals a significant disconnect between the information disseminated by extension agents and what farmers ultimately receive. This trend is reflected in a low level of content match and a general lack of engagement, pointing to potential breakdowns in the information transfer process. Notably, this mismatch is considerably more pronounced among female farmers, with only 22.3% receiving matched content compared to approximately 54.6% of their male counterparts. Land ownership, commodity type and membership of farmer groups play a significant role in content mismatches. In term of heterogeneity in ICT usage, the findings show that telephone calls and WhatsApp are the most prevalent ICT tools used by agents to disseminate digital content to farmers. While there is no significant gender difference in ICT use of among extension agents, female farmers lag behind their male counterparts in using ICT. Organizational support and infrastructure play a key role in determining ICT usage among extension agents. By contrast, farmers’ usage of various ICT types is significantly determined by land ownership, commodity type, individual capacity, individual perception of ICT barriers, membership of farmer groups, and the frequency of meetings with extension agents. These findings underscore that female farmers confront not only face barriers to accessing digital tools but also often have their interests overlooked in contents disseminated by agents, leading to lack of interest and engagement. It is crucial to provide reliable infrastructure, adequate ICT facilities, and capacity-building initiatives within the extension organization environment to improve ICT usage among extension agents. For farmers, targeted assistance and training programs, increased female participation in extension activities, and the delivery of tailored contents that meets their specific needs could significantly improve engagement and involvement. Chapter three analyzes the performance of field extension agents in Indonesia using an aggregate performance indicator comprising timeliness, targeting, and content dimensions while capturing both institutional arrangements and demographic characteristics in explaining the performance. For the methodology, this chapter uses data from an online survey of a nationally representative sample of 1,974 field extension agents randomly selected from the roster of national extension agents. This cost-effective approach enables rapid data collection and measuring performance during unforeseen events such as the Covid-19 pandemic. Its applicability extends to a wide range of contexts and regions. The study employs binary and ordinal probit models to analyze the performance of extension agents and the relevant factors involved. The results show that improved performance of field extension agents is associated with advanced career progression, the availability of external funding, the opportunity to collaborate with various stakeholders including non-governmental organizations, private sectors and financial organizations, involvement in government programs, the implementation of disciplinary measures, and the use of various extension methods. It is suggested that the government should encourage collaboration, secure funding from external sources, and establish a system of rewards and punishment to promote performance, while encouraging innovative extension service methods. Chapter four emphasizes that efforts to increase farm technical efficiency (TE) can take many forms, including government interventions to help smallholder farmers, such as those in Indonesia's rice farming. This chapter explores how such interventions—notably the adoption of certified seeds and the provision of extension services—affect TE. Using a panel dataset of smallholder farmers enables capturing the dynamics of TE over time while accounting for unobserved variability. This chapter employs a stochastic metafrontier production function to demonstrate the TE associated with various farming strategies. The findings show that users of certified seeds had slightly higher TE than non-users, although the lower metafrontier TE among certified seed users emphasizes the need for a more holistic approach to technical advancement. It is essential to strengthen seed supply chains by enhancing the infrastructure and logistics for distributing certified seeds, ensuring that smallholder farmers have easy access to quality seeds. In terms of factors influencing inefficiency, the family head’s education level, row planting technique implementation, regional variances, and the percentage of on-farm income all substantially influence TE. Meanwhile, the extension services intervention not only improves TE but also results in much higher technology gap ratios and metafrontier TE than among non-beneficiaries. This suggests that extension services play a crucial role in improving farmers’ abilities to adopt new technologies and improve their farming techniques. Expanding agricultural extension services is also crucial, with increased funding and resources dedicated to providing tailored advice and support to smallholder farmers. This dissertation delves into the various initiatives to address the challenges encountered by smallholder farmers, with a particular focus on leveraging the potential of extension and advisory services. It also highlights broad challenges related to limited access, poor connectivity, and inadequate extension services, which require several interventions including improving institutional arrangements such as promoting public-private partnerships and enhancing management. Promoting digital inclusion by encouraging digital training programs and providing gender-sensitive content is also crucial. To support extension services, integrating ICT into the daily tasks of extension agents is essential. At the same time, the government should increase investment in infrastructure.
Mungbean response to regulated deficit irrigation: a trade‐off between productivity and adaptability?
(2025) Pataczek, Lisa; Hakenberg, Tim; Hilger, Thomas; Nair, Ramakrishnan M.; Schafleitner, Roland; Asch, Folkard; Cadisch, Georg
Water scarcity, elevated temperatures, as well as pests and diseases have been demonstrated to have a detrimental effect on the yield potential of mungbean ( Vigna radiata ). The cultivation of improved mungbean genotypes with regulated deficit irrigation (RDI), a water‐saving irrigation strategy, has been identified as a promising approach to enhance yield stability of the crop and ensure food security. Thus, the purpose of this study was to identify adaptation strategies and possible trade‐offs to drought of mungbean genotypes under deficit irrigation and the effect on yield by investigating in particular assimilate re‐allocation. Four genotypes (NM11, AVMU 1604, AVMU 1635, KPS2) were cultivated in a greenhouse under three treatments of RDI with depletion fractions as a percentage of total available soil water (TAW) of 0.45, 0.65, and 0.8, corresponding to a recommended irrigation schedule, moderate and severe water deficit, respectively. Samples were collected at the flowering and maturity stages, and the dry matter, dry matter partitioning, yield, harvest index, pod harvest index, water use efficiency, and carbon‐13 isotope discrimination to estimate transpiration efficiency were determined. The study found that productivity (i.e., grain yield) was not lowered as a trade‐off of adaptability to water deficit irrigation. The genotypes either did not respond to deficit irrigation (KPS2 and AVMU 1635) in terms of grain yield or exhibited increased remobilisation of assimilates, either from pod walls to seeds (NM11) or from vegetative plant parts to pods/seeds (AVMU 1604), thereby increasing yields by 38% and 52%, respectively, under water deficit. However, the genotype KPS2 demonstrated stable yields and the greatest harvest index/pod harvest index (36%/69%) across all RDI treatments, suggesting superior adaptability to fluctuating water availability and efficient resource allocation, providing a suitable choice for a range of environmental conditions.
Nematode community structure suggests perennial grain cropping cultivation as a nature‐based solution for resilient agriculture
(2024) Förster, Alena; Hohberg, Karin; Rasche, Frank; Emmerling, Christoph
Introduction: Conventional agricultural land‐use may negatively impact biodiversity and the environment due to the increased disturbances to the soil ecosystem by tillage, for example. Cultivation of the perennial grain intermediate wheatgrass ( Thinopyrum intermedium , IWG, Kernza®) is a nature‐based solution for sustainable agriculture, improving nutrient retention mainly through its extensive root system. Nematodes serve as sensitive bioindicators, detecting early changes in the soil food web, reflecting in changes in their community structure. Materials and Methods: IWG and annual wheat sites in South France, Belgium and South Sweden were investigated in April 2022 for two depths (5–15 cm; 25–35 cm) to evaluate the difference in nematode community structure among the cropping systems. Results: Sites with IWG cultivation held an accumulation of structure indicators (c‐p 3–5 nematodes) compared to sites with annual wheat cultivation. A generalised linear mixed model revealed significantly more root feeders, especially for the subsoil, under IWG as a result of the perennial cultivation. The maturity index, plant‐parasitic index, channel index and structure index were greater for IWG sites. The enrichment index was greater for annual wheat sites due to the dominance of bacterivores and enrichment indicators (c‐p 1 nematodes). The nematode community structure (weighted faunal profile analysis) indicates IWG sites as being a generally undisturbed system with efficient nutrient cycling and balanced distribution of feeding types, as well as higher metabolic footprint values for root feeders (including plant‐parasitic nematodes) and fungivores. Annual wheat sites, on the other hand, held indicators of a disturbed system with increased occurrence of opportunistic species and a more bacterial driven pathway. The topsoil had an increased occurrence of structure indicators in both cropping systems. Conclusion: IWG creates favourable conditions for a diverse food web, including improved nutrient cycling and a heterogeneous resource environment, regardless of climatic conditions, establishing it as a stable and resilient agricultural management system.
Effects of Bacillus spp. inoculation on suggested shoot tolerance mechanisms in lowland rice (Oryza sativa L.) grown under iron toxicity
(2025) Weinand, Tanja; Asch, Julia; Asch, Folkard
Background: In areas of lowland rice production, high iron concentrations in the soil often lead to yield reductions. Local adapted varieties possess different adaptation mechanisms, which, however, are not fully understood. Previous studies have shown that endophytic bacteria can influence plant tolerance to abiotic stresses, including iron toxicity. Aim: This study aims at analyzing the effects of different Bacillus isolates on distinct shoot tolerance mechanism in different rice cultivars grown under iron toxicity. Methods: Three lowland rice cultivars, varying in their tolerance against iron toxicity (IR31785‐58‐1‐2‐3‐3, Sahel 108, Suakoko 8), were inoculated with three Bacillus strains (two of B. pumilus and one of B. megaterium ). One week after Bacillus inoculation plants were subjected to high iron levels (1000 ppm) for 7 days. Leaf symptom scoring was used to assess tolerance levels. Activities of ascorbate peroxidase (APX), glutathione reductase (GR), catalase (CAT), superoxide dismutase (SOD), and guaiacol peroxidase (PRX) were measured by spectrophotometric assays. Transcription of genes related to iron toxicity ( OsFER, OsFRO1, OsNRAMP6 ) was determined by RT‐qPCR. Bacterial production of NO was evaluated by measuring nitrite levels in the culture supernatants. Results: In general, iron toxicity affected the activities of APX, GR, CAT, and PRX but not SOD activity. Only PRX activity in response to iron differed between cultivars with a significantly stronger increase in IR31785‐58‐1‐2‐3‐3. Inoculation with B. pumilus Ni9MO12 led to higher activity of CAT in the leaf sheaths of all cultivars and an increase in GR activity in the sheaths that was significantly higher in Suakoko 8. In the young leaf blades of IR31785‐58‐1‐2‐3‐3, transcription of OsFRO1 and OsNRAMP6 was not significantly affected by Bacillus inoculation, whereas accumulation of OsFER mRNA was significantly higher in iron‐stressed, B. pumilus Ni9MO12 inoculated plants compared to non‐inoculated, non‐iron‐stressed plants. Nitrite concentration as an indicator for NO production was increased in B. pumilus Ni9MO12 culture supernatants. Conclusion: Our results show that in the sensitive cultivar IR31785‐58‐1‐2‐3‐3 tolerance to iron toxicity increases when inoculated with B. pumilus Ni9MO12, coinciding with higher levels of ferritin transcription. NO production by the Bacillus isolate might confer the promotion of OsFER gene transcription in the inoculated plants.
Mapping saline groundwater under rice‐paddy fields in Vietnam's Mekong Delta
(2025) Nguyen, Van Hong; Germer, Jörn; Pham, Tien Duy; Asch, Folkard
Climate change, decreased river flow and land subsidence lead to saltwater intrusion posing a significant threat to rice production in Vietnam's Mekong Delta (VMD), one of the world's largest rice exporting regions. Soil salinity in the VMD can be caused by saltwater intrusion into lowland areas through the canal system, or by capillary rise of water from the near surface saline water table, both resulting in salt accumulation in the top soil. Developing appropriate management strategies for adapting rice production systems of the VMD to climate change, both in terms of water and salinity management, requires characterizing and subsequently monitoring of the spatial distribution and temporal dynamics of salinity in the near‐surface aquifers underneath the rice producing area. The distribution of subsurface salinity was investigated using electrical resistivity tomography in the VMD's province, Tra Vinh, as a case study area. Soil salinity was measured for profiles of approximately 300 m length at 44 locations along geological transects in a case study area. Results show that saline water appears at a shallow depth, particularly along the coast and the lower reaches of rivers. Double‐cropped rice fields seem to be more susceptible to salinization via the near‐surface aquifer than other rice cropping systems. The study suggests that temporal fluctuations of the near‐surface aquifer and the dynamics of the exchange between the river and the shallow aquifer need to be investigated in future research.
Love your wet grass! Dry season grazing reserves show highest grass regrowth in communal semi-arid rangelands of Tanzania
(2024) Baumgartner, Sabine A.; Smith, Stuart W.; Bartzke, Gundula S.; Laizar, Oloshiro; Ploechl, Jane F.; Michler, Lena M.; Naro, Elizabeth M.; Treydte, Anna C.
Land management by seasonal migratory herding, traditionally implemented by pastoralists, has allowed semi-arid rangeland ecosystems to remain productive and resilient to highly erratic, seasonal rainfall patterns. Changing pastoralist practices and rainfall patterns due to climate change have the potential to negatively influence the resilience of rangelands. To test the impact of different communal rangeland practices and increasing frequency of disturbance on the rangelands’ vegetation, we established a clipping experiment in three rangeland management types: rainy season rangeland, dry season rangeland and seasonal exclosures, in the Maasai Steppe, northern Tanzania. Across these rangeland management types, we tested two clipping frequencies monthly vs. once per growing period and either fenced or open to grazing (herbivory) over two consecutive growing periods. We found that rainy season rangeland exhibited lowest regrowth rates and highest proportion of bare ground across herbivory, clipping frequency and growing period. When rainfall was low, seasonal exclosures showed lowest proportion of bare ground across herbivory and clipping frequency and plots that were seasonally clipped and excluded herbivores generated significantly more grass biomass, higher grass regrowth rates and lowest proportion of bare ground compared to all other treatments. Excluding herbivores had little impact on the vegetation biomass and cover but had a positive impact on grass regrowth rates when rainfall was high. Seasonal clipping allowed for lower proportion of bare ground, and in most cases higher regrowth rates and higher biomass compared to monthly clipping. We conclude that traditional seasonal migratory herding is a relevant concept to sustain rangeland productivity and resilience under increasing intensity of disturbance if grazing pressure on rainy season rangelands is adapted to rainfall conditions and sufficient resting time after heavy defoliation is granted. Dry season grazing (including rainy season resting) proved to be the most sustainable concept to maintain regrowth and control erosion.
Analysis of long-term prices of micronutrient-dense and starchy staple foods in developing countries
(2022) Alioma, Richard; Zeller, Manfred; Ling, Yee Khor
The continued price increase in food commodities has long been a concern to academia and policymakers because of its substantial impact on poor consumers. Existing literature has concentrated on the cost of micronutrient-dense and starchy staple foods and the price rise in different commodities. Yet, the long-term price growth of micronutrient-dense and starchy staple foods and the price growth gap between micronutrient-dense foods and starchy staple foods have not been given much attention. The paper aimed to estimate the long-term trends in prices and volatility of micronutrient-dense and starchy staples and identify factors that have sustained the growth in prices of food commodities in developing countries. We have used the autoregressive and panel autoregressive distributed lag models to analyse the trends in relative prices and the effects of income growth. The results showed that micronutrient-dense food prices in real terms grew on average by 0.03% per month more than starchy staple food prices, with the expectation of a 12% growth gap in the next 30 years. The volatility of micronutrient-dense food items exceeds starchy staple foods in most domestic markets. Also, the prices of micronutrient-dense foods were more volatile in international markets than in most developing countries. Income growth in developing countries was one of the factors that contributed to the declining relative price of micronutrient-dense food commodities. Other factors, such as the high production of staple foods and their price stabilization policies, may have caused price trends to persist. Policies that enhance price stabilization for micronutrient-dense foods, supplementation, fortification, dietary diversity, and nutrition-sensitive interventions such as biofortification may be adopted in developing countries.
Nitrogen excretion and utilisation of dairy cows grazing temperate semi- natural grasslands
(2024) Perdana-Decker, Sari; Velasco, Elizabeth; Werner, Jessica; Dickhoefer, Uta
Diets reliant on grazed, temperate herbage are prone to greater nitrogen (N) losses via urine than balanced stall-fed diets which poses a greater risk for N emissions. Measures for improving the N utilisation in grazing-based dairy cattle systems are predominantly investigated on homogenous clover-ryegrass pastures with high herbage yields and nutritional quality. In contrast, grazing-based systems reliant on less external inputs (e.g., synthetic fertilisers or concentrates) using semi-natural grassland as main feed source, such as in large parts of Central Europe, received less attention. The N utilisation and excretion of grazing cows in low-input dairy farms were, thus, investigated on nine commercial organic dairy farms in South Germany across one to four periods per farm. The dataset captured a diverse set of dairy production systems comprising 323 individual animal observations. A mean (± one SD) milk production, DM intake (DMI), and pasture DMI of 23.9 kg (± 5.35), 21.0 kg (± 3.21), and 11.3 kg/d (± 4.83), respectively, was determined. Feed intake was estimated using titanium dioxide and faecal CP concentration as markers of faecal excretion and diet digestibility, respectively. Milk N use efficiency (MNE; i.e., milk N secretion as share of N intake) averaged 24.7 g/100 g N intake (± 5.91), which is greater than observations in temperate, high-input grazing systems but lower than in cows receiving balanced diets in the barn. The MNE and another seven indicators of N utilisation and excretion displayed a wide range of values. The grazing management factors explaining this variation were, thus, identified via backward elimination. The supplementation strategy had the greatest potential for manipulating N utilisation and excretion of dairy cows. Increasing shares of fresh forages (i.e., meadow grass or clover-grass leys) as well as of hay in supplement DMI increased N utilisation (e.g., MNE) and decreased urinary N excretion (e.g., urinary N to creatinine ratio), while increasing shares of concentrates in supplement DMI are related to lower N losses via urine. At the same time, increases in total supplement DMI reduced N utilisation and increased urinary N excretion. Hence, full-time grazing combined with supplementation of fresh forage and hay in the barn is a viable option for low-input, grazing-based dairy operations with moderate levels of N losses.
The road to integrate climate change projections with regional land‐use–biodiversity models
(2024) Cabral, Juliano Sarmento; Mendoza‐Ponce, Alma; da Silva, André Pinto; Oberpriller, Johannes; Mimet, Anne; Kieslinger, Julia; Berger, Thomas; Blechschmidt, Jana; Brönner, Maximilian; Classen, Alice; Fallert, Stefan; Hartig, Florian; Hof, Christian; Hoffmann, Markus; Knoke, Thomas; Krause, Andreas; Lewerentz, Anne; Pohle, Perdita; Raeder, Uta; Rammig, Anja; Redlich, Sarah; Rubanschi, Sven; Stetter, Christian; Weisser, Wolfgang; Vedder, Daniel; Verburg, Peter H.; Zurell, Damaris
Current approaches to project spatial biodiversity responses to climate change mainly focus on the direct effects of climate on species while regarding land use and land cover as constant or prescribed by global land‐use scenarios. However, local land‐use decisions are often affected by climate change and biodiversity on top of socioeconomic and policy drivers. To realistically understand and predict climate impacts on biodiversity, it is, therefore, necessary to integrate both direct and indirect effects (via climate‐driven land‐use change) of climate change on biodiversity. In this perspective paper, we outline how biodiversity models could be better integrated with regional, climate‐driven land‐use models. We initially provide a short, non‐exhaustive review of empirical and modelling approaches to land‐use and land‐cover change (LU) and biodiversity (BD) change at regional scales, which forms the base for our perspective about improved integration of LU and BD models. We consider a diversity of approaches, with a special emphasis on mechanistic models. We also look at current levels of integration and at model properties, such as scales, inputs and outputs, to further identify integration challenges and opportunities. We find that LU integration in BD models is more frequent than the other way around and has been achieved at different levels: from overlapping predictions to simultaneously coupled simulations (i.e. bidirectional effects). Of the integrated LU‐BD socio‐ecological models, some studies included climate change effects on LU, but the relative contribution of direct vs. indirect effects of climate change on BD remains a key research challenge. Important research avenues include concerted efforts in harmonizing spatial and temporal resolution, disentangling direct and indirect effects of climate change on biodiversity, explicitly accounting for bidirectional feedbacks, and ultimately feeding socio‐ecological systems back into climate predictions. These avenues can be navigated by matching models, plugins for format and resolution conversion, and increasing the land‐use forecast horizon with adequate uncertainty. Recent developments of coupled models show that such integration is achievable and can lead to novel insights into climate–land use–biodiversity relations.

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