Alexandra Klein

University of Freiburg | Albert-Ludwigs-Universität Freiburg · Chair of Nature Conservation and Landscape Ecology

Timber‐oriented forest management profoundly alters forest structure and composition, with complex effects on associated biodiversity. However, while species' responses to forest management and resulting structural characteristics have been the subject of numerous studies, direct and indirect effects that cascade through trophic levels are rarely d...

One of the greatest challenges of the 21st century is the conservation of biodiversity. Human-influenced landscapes often negatively affect pollinator health and diversity at various scales resulting in limiting pollination services, which is crucial for our food security and the maintenance of biodiversity. SPHERE is an innovative Master course th...

Ecosystem services such as pollination and biocontrol may be severely affected by emerging nano/micro-plastics (NMP) pollution. Here, we synthesize the little-known effects of NMP on pollinators and biocontrol agents on the organismal, farm and landscape scale. Ingested NMP trigger organismal changes from gene expression, organ damage to behavior m...

GfÖ 2024 conference poster contribution at TUM Freising

Disclaimer: This work is currently under revision, but pre-print document is available via DOI Link above, or here in the description. In case of difficulty in access, feel free to request the full print. Thank you! ------------ ----- Abstract ----- Body size determines mobility and fitness of insects in various ways. Yet, especially in parasitoi...

Ecosystem functioning depends on biodiversity at multiple trophic levels, yet relationships between multitrophic diversity and ecosystem multifunctionality have been poorly explored, with studies often focusing on individual trophic levels and functions and on specific ecosystem types. Here, we show that plant diversity can affect ecosystem functio...

Environmental factors can influence ecological networks, but these effects are poorly understood in the realm of the phylogeny of host-parasitoid interactions. Especially, we lack a comprehensive understanding of the ways that biotic factors, including plant diversity, tree identity, genetic diversity, overall community composition of higher trophi...

Environmental factors can influence ecological networks, but these effects are poorly understood in the realm of the phylogeny of host-parasitoid interactions. Especially, we lack a comprehensive understanding of the ways that biotic factors, including plant diversity, tree identity, genetic diversity, overall community composition of higher trophi...

Environmental factors can influence ecological networks, but these effects are poorly understood in the realm of the phylogeny of host-parasitoid interactions. Especially, we lack a comprehensive understanding of the ways that biotic factors, including plant diversity, tree identity, genetic diversity, overall community composition of higher trophi...

Aus der literatur- und erfahrungsbasierten Analyse der Naturschutzverwaltung in den Bundesländern in Teil 1 des Beitrags werden 20 Thesen abgeleitet. Mit diesen Anregungen soll ein grundlegender Reformprozess eingeleitet werden, um die Naturschutzverwaltung für das 21. Jahrhundert zukunftsfähig zu gestalten. Diese betreffen (1) organisationale Stru...

A nationwide survey of opinions, with the participation of scientists and practitioners as well as evaluation of scientific work, shows that nature conservation administration is less and less able to fulfil its mandate. This initially becomes clear when politically set biodiversity targets are missed. Behind this is a bundle of complex challenges,...

Automated cameras (including camera traps) are an established observation tool, allowing, for example the identification of behaviours and monitoring without harming organisms. However, limitations including imperfect detection, insufficient data storage and power supply restrict the use of camera traps, making inexpensive and customizable solution...

Infectious and parasitic agents (IPAs) and their associated diseases are major environmental stressors that jeopardize bee health, both alone and in interaction with other stressors. Their impact on pollinator communities can be assessed by studying multiple sentinel bee species. Here, we analysed the field exposure of three sentinel managed bee sp...

Occurrences of introduced and invasive pollinators are increasing worldwide. To predict the potential impacts of exotic bees on native ecosystems we need to understand their ecological interactions. Life history traits are fundamental for understanding ecological interactions and often help to explain the spread of exotic species. We conducted home...

Bees are exposed to various stressors, including pesticides and lack of flowering resources. Despite potential interactions between these stressors, the impacts of pesticides on bees are generally assumed to be consistent across bee-attractive crops, and regulatory risk assessments of pesticides neglect interactions with flowering resources. We ass...

1. Antagonistic host-parasitoid interactions can be quantified using bipartite and metanetworks, which have the potential to reveal how habitat structural elements relate to this important ecosystem function. 2. Here, we analysed the host-parasitoid interactions of cavity-nesting bees and wasps, as well as their abundance, diversity and species ric...

Sustainable agriculture requires balancing crop yields with the effects of pesticides on non-target organisms, such as bees and other crop pollinators. Field studies demonstrated that agricultural use of neonicotinoid insecticides can negatively affect wild bee species1,2, leading to restrictions on these compounds³. However, besides neonicotinoids...

In an agricultural landscape, production and conservation ideally go hand in hand. In a win-win scenario, conservation measures provide support for biodiversity and crop production, mediated by pollination for example. Hedges and flower strips are conservation measures that support pollinating insects, such as wild bees and hoverflies. They can be...

Managed bees and other pollinators are exposed to a wide variety of stressors and these often act in combination. Historically, most risk assessments and research have focused on the impacts of individual stressors on honey bees. However, there is broad scientific consensus that there is a need for a systems-based risk assessment approach and a pos...

Clarivate’s Highly Cited Researchers (HCR) list is one of the most important quantitative performance indicators in science and influences individual careers and also the reputation of research institutions. However, many researchers and representatives of institutions and funding agencies are not familiar with the method that is applied to generat...

Biodiversity is the manifestation of life on our planet and provides manifold benefits for humans. Yet we destroy ecosystems and drive species to extinction. We submit that anthropogenic biodiversity loss does not yet receive sufficient public attention, although biodiversity conservation and its sustainable use are key to mitigate global crises. E...

Ecological intensification has been embraced with great interest by the academic sector but is still rarely taken up by farmers because monitoring the state of different ecological functions is not straightforward. Modelling tools can represent a more accessible alternative of measuring ecological functions, which could help promote their use among...

Policies and management practices for managed bees and other pollinators are increasingly reliant on the availability of high quality data in order to inform them. This in turn requires the widespread adoption of state-of-the-art standardised methods and approaches so that new data and knowledge are both robust and trustworthy. The PoshBee project...

The challenges of bee research in Asia are unique and severe, reflecting different cultures, landscapes, and faunas. Strategies and frameworks developed in North America or Europe may not prove applicable. Virtually none of these species have been assessed by the IUCN and there is a paucity of public data on even the basics of bee distribution. If...

Grasslands are globally distributed and naturally occurring; however, in Europe,most grasslands are anthropogenically created or altered by livestock grazing or mowing. Low-intensity use and management have led to species-rich communities in European grasslands. The intensification of crop production and livestock farming with stabling throughout t...

Insects, as one of the most species‐rich taxa with enormous taxonomic, behavioural and functional diversity, are in decline. Bees and wasps are especially crucial for ecosystems as pollinators or to control populations of other insects. To understand population drivers, comprehensive knowledge about top‐down and bottom‐up interactions, including al...

Background Pollinating insects provide economically and ecologically valuable services, but are threatened by a variety of anthropogenic changes. The availability and quality of floral resources may be affected by anthropogenic land use. For example, flower-visiting insects in agroecosystems rely on weeds on field edges for foraging resources, but...

Introduction Heterogeneity in composition and spatial configuration of landscape elements support diversity and abundance of flower-visiting insects, but this is likely dependent on taxonomic group, spatial scale, weather and climatic conditions, and is particularly impacted by agricultural intensification. Here, we analyzed the impacts of both asp...

Unravelling the relationships between insect population dynamics and habitat properties is often complex. Established theoretical concepts, which predict an influence of available resources on sex determination, have often not been tested with quantitative field data. Cavity-nesting Hymenoptera are suitable to assess the influence of habitat proper...

Carbon-focused climate mitigation strategies are becoming increasingly important in forests. However, with ongoing biodiversity declines we require better knowledge of how much such strategies account for biodiversity. We particularly lack information across multiple trophic levels and on established forests, where the interplay between carbon stoc...

Biodiversity is the foundation of our lives. Yet we destroy ecosystems and drive species to extinction. Human-induced biodiversity loss does not yet receive sufficient public attention, although biodiversity is fundamental for dealing with global environmental crises. Effective communication of biodiversity-related knowledge is challenging but cruc...

1. The diversity in meadows is affected by numerous aspects, such as the amount and type of fertilisation and the timing and frequency of cutting. The effects of mowing on the diversity of plants and insects have been studied in detail. However, the effect of mulching (vegetation is cut, shredded, and left in place, instead of being removed) on ins...

Under the terms of the PoshBee agreement, the members tasked with delivering Work Package 7 carried out semi-field and field studies on honey bees, bumble bees and solitary bees. These studies involved the exposure of the bees to more than one stressor, for example a fungicide and an insecticide or a fungicide and a nutritional deficiency. This is...

Retention forestry promotes certain forest structural elements to enhance biodiversity. It is unclear however to what extent retention measures are suited to enhance the biodiversity of bees and wasps, and how relationships to structural elements promoted by retention may differ when habitat-based classifications are accounted for. Here, we analyze...

Forests in Germany are occupied with roads, paths, and trails with a density of 5.03 km/km². Their construction and maintenance create a network of verges promoting flowering plants. Whether these verges are visited by bees, which factors are determining their abundance, diversity, and composition, and which flowering resources are used is unknown....

Addressing global biodiversity loss requires an expanded focus on multiple dimensions of biodiversity. While most studies have focused on the consequences of plant interspecific diversity, our mechanistic understanding of how genetic diversity within plant species affects plant productivity remains limited. Here, we use a tree species × genetic div...

Mulching, cutting of the vegetation without plant biomass removal, is a common alternative to mowing. The aim of our study was to find out if the mulching of forest meadows at different time points affects cavity-nesting bees and wasps. We exposed trap nests for cavity-nesting bees and wasps at 24 forest meadows in south-western Germany over 2 year...

Recent studies have emphasized forests as crucial habitat for wild bees. In Europe, most forests are managed following the principles of close-to-nature silviculture, which combine timber production and nature conservation. However , open late and early successional stages within these forests are largely missing, which could be important for wild...

Pesticide exposure and food stress are major threats to bees, but their potential synergistic impacts under field-realistic conditions remain poorly understood and are not considered in current pesticide risk assessments. We conducted a semi-field experiment to examine the single and interactive effects of the novel insecticide flupyradifurone (FPF...

Wild bees importantly pollinate both crop and wild plants. Yet, in intensive agricultural landscapes, wild bees are rare due to resource limitations of nectar and pollen. Flower strips and hedges are often used as resource enhancements for wild bees to overcome this shortage, but provide floral resources only during specific time periods. To sustai...

To provide a complete portrayal of the multiple factors negatively impacting insects in agricultural landscapes it is necessary to assess the concurrent incidence, magnitude, and interactions among multiple stressors over substantial biogeographical scales. Trans-national ecological field investigations with wide-ranging stakeholders typically enco...

published in Bienen & Natur

During the main COVID-19 global pandemic lockdown period of 2020 an impromptu set of pollination ecologists came together via social media and personal contacts to carry out standardised surveys of the flower visits and plants in gardens. The surveys involved 67 rural, suburban and urban gardens, of various sizes, ranging from 61.18° North in Norwa...

Background Retention forestry is a management strategy aiming to mitigate biodiversity loss by retaining structural elements such as dead trees that would otherwise be removed. Here we analyze the biomass, diversity and abundance among forest beetles collected using window traps on 128 1-ha forest sites reflecting gradients in the amount of structu...

Flower-visiting insects in agroecosystems forage on field-edge weeds often exposed to agrochemicals that may compromise the quality of their floral resources. We conducted complementary field and greenhouse experiments to evaluate the: 1) effect of low concentrations of agrochemical exposure on nectar and pollen quality and 2) relationship between...

Wild bee populations are declining due to human activities, such as land use, which strongly affect the composition and diversity of available plants and food sources. The chemical composition of food (i.e. nutrition), in turn, determines health, resilience and fitness of bees. However, for pollinators, the term health is recent and subject to deba...

Most forests in Europe are managed but differ in their management intensity. This has different implications for structural- and environmental conditions and subsequently for the conservation of ecological communities, their interactions and functional consequences. Differences in silvicultural treatments, especially those promoting rare habitat st...

Pesticide exposure is considered a major driver of pollinator decline and the use of neonicotinoid insecticides has been restricted by regulatory authorities due to their risks for pollinators. Impacts of new alternative sulfoxamine-based compounds on solitary bees and their potential interactive effects with other commonly applied pesticides in ag...

Addressing global biodiversity loss requires an expanded focus on multiple dimensions of biodiversity. While most studies have focused on the consequences of plant interspecific diversity, our mechanistic understanding of how the diversity within a given plant species (genetic diversity) affects plant productivity remains limited. Here, we use a tr...

Bees are exposed to various stressors, including pesticides and lack of flowering resources. Despite potential interactions between these stressors, the impacts of pesticides on bees are generally assumed to be consistent across bee-attractive crops, and regulatory risk assessments of pesticides neglect interactions with flowering resources. Furthe...

Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop y...

In intensive agricultural landscapes semi-natural habitats for pollinators are often limited, although willingness to establish pollinator habitat is increasing among farmers. A common pollinator enhancement measure is to provide flower strips, but existent or improved hedgerows might be more effective. In this study, we compare the effectiveness o...

Animal pollinators are globally threatened by anthropogenic land use change and agricultural intensification. The yield of many food crops is therefore negatively impacted because they benefit from biotic pollination. This is especially the case in the tropics. For instance, fruit set of Coffea arabica has been shown to increase by 10–30% in planta...

published in BWagrar

Habitat disturbance can have negative impacts on biodiversity, such as reducing species richness. The effects of habitat disturbances on parasite infections of host species, potentially altering their survival rate and thus abundance, are less well known. We examined the influence of forest logging in combination with seasonality, host abundance, h...

Sulfoximines, the next generation systemic insecticides developed to replace neonicotinoids, have been shown to negatively impact pollinator development and reproduction. However, field-realistic studies on sulfoximines are few and consequences on pollination services unexplored. Moreover, the impacts of other agrochemicals such as fungicides, and...

• Floral nectar is considered the most important floral reward for attracting pollinators. It contains large amounts of carbohydrates besides variable concentrations of amino acids and thus represents an important food source for many pollinators. Its nutrient content and composition can, however, strongly vary within and between plant species. The...

Functional traits mediate the response of communities to disturbances (response traits) and their contribution to ecosystem functions (effect traits). To predict how anthropogenic disturbances influence ecosystem services requires a dual approach including both trait concepts. Here, we used a response–effect trait conceptual framework to understand...

Flower strips are a frequently adopted measure to conserve insects, especially pollinators, and are subsidized as Agri-Environmental Scheme in many regions. They provide a high quantity of flowers, but their flower species composition and phenological development is mostly uniform. This may result in only a fraction of pollinator species being enha...

From regional to global scales, anthropogenic environmental change is causing biodiversity loss and reducing ecosystem functionality. Previous studies have investigated the relationship between plant diversity and functional insect communities in temperate and also in tropical grasslands and forests. However, few studies have explored these dynamic...

Reversing the decline of biodiver-sity in European agricultural land-scapes is urgent. We suggest eightmeasures addressing politics, eco-nomics, and civil society to instigatetransformative changes in agricul-tural landscapes. We emphasizethe need for a well-informed societyand political measures promotingsustainable farming by combiningfood produc...

The quality of wintering habitats, such as depth of snow cover, plays a key role in sustaining population dynamics of Arctic lemmings. However, few studies so far investigated habitat use during the Arctic winter. Here, we used a unique long-term time series to test whether lemmings are associated with topographical and vegetational habitat feature...

The importance of wild bees for crop pollination is well established, but less is known about which species contribute to service delivery to inform agricultural management, monitoring and conservation. Using sites in Great Britain as a case study, we use a novel qualitative approach combining ecological information and field survey data to establi...

PoshBee is a 5-year funded project (2018-2023) that aims to support healthy bee populations, sustainable beekeeping, and consequently pollination for crops and wildflowers across Europe. To do this we take a range of approaches, from the laboratory to the field, from molecules to ecosystems, and from fundamental science to risk assessment. This doc...