Litter Controls Earthworm-Mediated Carbon and Nitrogen Transformations in Soil from Temperate Riparian Buffers

Nutrient cycling in riparian buffers is partly influenced by decomposition of crop, grass, and native tree species litter. Nonnative earthworms in riparian soils in southern Quebec are expected to speed the processes of litter decomposition and nitrogen (N) mineralization, increasing carbon (C) and N losses in gaseous forms or via leachate. A 5-month microcosm experiment evaluated the effect of Aporrectodea turgida on the decomposition of 3 litter types (deciduous leaves, reed canarygrass, and soybean stem residue). Earthworms increased CO2 and N2O losses from microcosms with soybean residue, by 112% and 670%, respectively, but reduced CO2 and N2O fluxes from microcosms with reed canarygrass by 120% and 220%, respectively. Litter type controlled the CO2 flux (soybean ≥ deciduous-mix litter = reed canarygrass > no litter) and the N2O flux (soybean ≥ no litter ≥ reed canarygrass > deciduous-mix litter). However, in the presence of earthworms, there was a slight increase in C and N gaseous losses of C and N relative to their losses via leachate, across litter treatments. We conclude that litter type determines the earthworm-mediated decomposition effect, highlighting the importance of vegetation management in controlling C and N losses from riparian buffers to the environment

How values and perceptions shape farmers' biodiversity management: insights from ten European countries

Farmers play a pivotal role in addressing biodiversity loss whilst maintaining food production. To rethink conservation in agricultural landscapes, it is crucial to understand their decisions regarding biodiversity and its management on the farms. In this study, we conducted 48 semi-structured interviews across ten European countries in 2021/22 to explore how farmers’ perceptions and valuations relate to their biodiversity management. Employing reflexive thematic analysis, we identified recurring patterns of shared meanings. Our findings underscore the profound influence of farmers’ biodiversity perceptions on their biodiversity management practices: 1) Narrow and targeted interventions were closely tied to instrumental values of biodiversity, whereas holistic management strategies were linked with recognising an inherent value of nature. 2) Targeted approaches were related to farmers’ interpretations of biodiversity as specific taxa and functions, relying on easily assessable and emotionally connoted indicators. 3) Holistic approaches aligned with a broader biodiversity concept and an emphasis on intricate functional relationships within ecosystems. 4) Actual decisions to implement measures were significantly constrained by perceived dependencies, namely production pathways, social dependencies, and landscape conditions. These findings raise a critical question about the prioritisation of ecocentric intrinsic versus anthropocentric instrumental values in conservation strategies. We propose an approach of ethical pluralism, acknowledging that instrumental values may provide practical solutions for certain challenges, while intrinsic values hold ethical significance, particularly in the context of complex or large-scale biodiversity conservation initiatives. Engaging in dialogue that accounts for diverse values will be essential for shaping effective and socially meaningful biodiversity conservation

Global data on earthworm abundance, biomass, diversity and corresponding environmental properties

Publisher Copyright: © 2021, The Author(s).Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ecological groups. This global dataset contains 10,840 sites, with 184 species, from 60 countries and all continents except Antarctica. The data were obtained from 182 published articles, published between 1973 and 2017, and 17 unpublished datasets. Amalgamating data into a single global database will assist researchers in investigating and answering a wide variety of pressing questions, for example, jointly assessing aboveground and belowground biodiversity distributions and drivers of biodiversity change.Peer reviewe

Global data on earthworm abundance, biomass, diversity and corresponding environmental properties

Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ecological groups. This global dataset contains 10,840 sites, with 184 species, from 60 countries and all continents except Antarctica. The data were obtained from 182 published articles, published between 1973 and 2017, and 17 unpublished datasets. Amalgamating data into a single global database will assist researchers in investigating and answering a wide variety of pressing questions, for example, jointly assessing aboveground and belowground biodiversity distributions and drivers of biodiversity change

Grassland farmers’ relationship with biodiversity: a case study from the northern Italian Alps

To successfully understand and shape biodiversity conservation in Alpine grasslands, it is crucial to understand how farmers’ relationship to biodiversity influences their goals and associated practices. We explored how farmers perceive and value biodiversity, how this is related to agricultural and land use practices, and how they view their roles in affecting it. Semi-structured interviews were conducted with 22 farmers in the northern Italian Alps and with 6 experts in the fields of grassland management, agriculture, and environmental conservation in 2020. The farmers’ answers were analyzed using a mental model approach, relational thinking, and the literature on the ‘good farmer’. The experts’ responses were used to discuss and contextualize the farmer’s answers. We found that the farmers’ mental model of biodiversity is associated to different aspects of agricultural management practices and farmers’ roles in mountain agricultural landscapes. Instrumental values of biodiversity are negative and strongly perceived as such by farmers, while relational values associated with biodiversity are positive, but more weakly perceived. These differing perceptions and values seem to be associated with two roles that farmers have, as producers and landscape stewards, and how they value fodder quantity and quality. Most farmers don’t include considerations related to the conservation of biodiversity in their management decisions, and mostly do not envision any changes in biodiversity or management in the future. Effective biodiversity conservation in Alpine grasslands will therefore need to tap into these dual roles and the associated instrumental and relational values of biodiversity for a meaningful dialogue on conservation

Optimal investment-reinsurance strategy for a jump-diffusion risk model

Abweichender Titel laut Übersetzung der Verfasserin/des VerfassersZsfassung in engl. SpracheDiese Arbeit beschäftigt sich mit der optimalen Investitions-Rückversicherungsstrategie für ein Jump-Diffusion Risikomodell mit Investment und proportionaler Rückversicherung, in welchem der Schadenprozess als Compound Poisson Prozess modelliert wird und der Investitionsprozess dem CEV-Modell folgt. Von wesentlichem Interesse ist das optimale Investitions-Rückversicherungsproblem der Maximierung des erwarteten exponentiellen Nutzens eines Endvermögens, welches eine wichtige Rolle in der Finanzmathematik als auch in der aktuariellen Praxis spielt. Durch die Verwendung der stochastischen Kontrolltheorie lassen sich explizite Ausdrücke für die optimale Investitions-Rückversicherungsstrategie wie auch für die Wertfunktion herleiten. Des Weiteren sind numerische Analysen angeführt, um die Auswirkung der Modellparameter auf die optimalen Strategien zu verdeutlichen.This thesis is about the optimal reinsurance-investment problem for the jump-diffusion risk model with investment and proportional reinsurance in which the aggregate claim process is a compound Poison process perturbed by diffusion and the investment process follows the CEV-model. The main focus is on studying the optimal investment-reinsurance problem of maximizing the expected exponential utility of terminal wealth which is an important and commonly-adopted function in the financial mathematics and actuarial practice. Explicit expressions for the optimal strategies and value functions are derived by using techniques of stochastic control theory. Also some numerical analysis are presented to illustrate the impact of some model parameters on the optimal strategies.5

Farmer-centered ecological intensification: using innovation characteristics to identify barriers and opportunities for a transition of agroecosystems towards sustainability

CONTEXT Ecological intensification (EI) describes farming practices that aim to use ecological processes for producing agricultural yields. While evidence for the ecological benefits of EI is plentiful, the question of how it can be more widely adopted by farmers, and why it has not been so far, remains pertinent, since only approximately 9% of the globally farmed land is currently managed with EI practices. We suggest that considering farmers as central while attending to farm and system level factors can help to identify barriers and facilitators to EI adoption. To do this, we look to diverse, overlapping bodies of literature encompassing EI practice details, systems thinking, and farmer adoption. Innovation characteristics is one framework that has been used to study farmer adoption of new farm management tools and practices. OBJECTIVE Our objective is to use innovation characteristics for identifying farmer, farm, and system level barriers and potential solutions to EI adoption. We then aim to synthesize broader lessons for a sustainability transition in agriculture. METHODS We treat EI as a suite of innovations, including practices, technologies, and knowledge. We explore how the innovation characteristics of EI - i.e. their relative advantage, compatibility, complexity, trialability and observability – manifest at each of three levels: farmer, farm, and system. We apply our approach to three case studies of EI adoption from different world regions: 1) managing landscape complexity in Germany, 2) installation of riparian buffers in the USA and 3) organic farming in India. RESULTS AND CONCLUSIONS An analysis of our case studies using innovation characteristics helped identify barriers to EI adoption and at what level these barriers should be addressed. Barriers included: uncoupled financial and farm-level ecological relative advantages of EI (system level), framing that is not in line with farm values and needs (farmer level), insufficient training for managing complex systems (farmer level), and time constraints for experimentation with and observation of EI effects (farm level). System level solutions could support training and experimentation with EI, empowering farmers by providing them with autonomy to adapt and apply EI as they see fitting. SIGNIFICANCE Using innovation characteristics and diverse bodies of knowledge allowed us to identify barriers, but also opportunities at farmer, farm, and system level. Abundant work focuses on convincing farmers of what science says is right, so showing farmers that barriers are not explicit to them is a helpful step forward in the transition towards sustainability

Working with or against multifunctional landscapes? A case study of land users’ local knowledge of grassland–forest transition zones in northeastern Germany

Maintaining or restoring landscape multifunctionality is essential to ensuring that landscapes provide a broad array of services. Increased multifunctionality means that there are more diverse land uses bordering each other. The areas in which land uses interact are transition zones; those between grasslands and forests could fulfill multiple purposes due to their special ecological characteristics that support the needs of diverse species. However, with their management practices, local land users often shape the characteristics of land-use transition zones, with implications for ecological processes that build the base for service provision. Local ecological knowledge of land users could give important insights into the basis of their decisions. Here, we explore how land users’ and farmers’ local knowledge shapes their management that contributes to the maintenance and restoration of multifunctional landscapes. We conducted 21 semistructured qualitative interviews with livestock farmers and local experts for agriculture and nature conservation using grassland–forest transition zones as a specific example for interdependent components of multifunctional landscapes. We found that local knowledge of the interviewed farmers can contribute to the maintenance or restoration of multifunctional landscapes in several ways: it provides insight into landscape functions in grassland–forest transition zones, it enables land users to use landscape function-grassland production synergies, and it provides insight into the perceived negative and positive contributions of forests to grassland production. The perceived negative contributions of forests to grassland production were an important driver for farmers’ management decisions. Farmers have a holistic view of both the field and the landscape. Managing landscapes for multifunctionality is dependent on this kind of holistic knowledge to identify synergies and trade-offs in landscape functions and how they contribute to agricultural production. However, current regulations such as the institutional separation of grassland and forest and grassland area-dependent direct payments prevent farmers from acting according to their local knowledge