Kirsten Jung

Understanding whether land use intensification causes regime shifts (i.e. persistent, large changes in ecosystem states) is of key importance for management, particularly if these shifts occur abruptly as thresholds in land use intensity are crossed. Further, these threshold responses can show hysteretic dynamics, where the transition between states cannot simply be undone by reducing land use intensity to its initial level, and instead larger changes are required. However, quantitative evidence for threshold responses and their dynamics remain scarce. Here we use a unique, long‐term grassland database in Germany to identify threshold responses to land use intensity. We include data on the response of 16 ecosystem functions (including plant biomass, herbivory, litter decomposition, pathogen infection, water recharge, C and N fluxes and retention and enzymatic activity) and the diversity of 21 taxa (including above‐ground and below‐ground taxa such as vascular plants, lichens, bryophytes, arthropods, vertebrates, fungi, protists and bacteria). Then, we use increased variance as an early warning signal to evaluate if threshold responses are indicative of critical transitions between states. Finally, we use temporal data to identify hysteretic dynamics associated with those transitions. We show that 5 out of 10 above‐ground taxa, fungal diversity, shoot biomass and soil N retention showed threshold responses to land use intensity, that is abrupt changes between extensively and intensively managed grasslands. Some of the thresholds were associated with increased variance in the response variables, suggesting a potential critical transition between ecosystem states. Time‐series analysis indicated that ecosystem functions showed a hysteretic response to land use intensity, but diversity measures did not. Our results suggest threshold responses to land use intensity are relatively common in the grasslands we studied. These thresholds show abrupt changes in the ecosystem when highly diverse extensively managed grasslands are managed slightly more intensively. Further, shifting back to the functioning seen in extensively managed grasslands may be challenging, as it requires larger reductions in land use intensity than those required to shift to the high intensity state. Identifying thresholds along land use gradients is critical to prevent ecosystem degradation and conserve biodiversity and ecosystem functions in semi‐natural grasslands. Read the free Plain Language Summary for this article on the Journal blog.

Since its consolidation as a sub‐discipline of ecology in the late 1990s, urban ecology has grown substantially, enhancing our understanding of how urbanization shapes biodiversity and how biodiversity adapts to urbanization. Inherently interdisciplinary in its scope and application, urban ecology is rooted in multiple theoretical and methodological foundations, potentially making the field overwhelming for newcomers as the key literature is scattered across multiple disciplines. Drawing on the collective expertise of editors and reviewers, we attempt to address common pitfalls noted in studies of biodiversity within urban ecosystems and suggest action items for both the new and experienced urban ecologist. Here, we present key concepts for framing hypothesis‐based urban biodiversity research questions, conceptualizing urban settings, accounting for spatial and temporal scales, selecting study systems and meaningful explanatory variables for research questions, and recognizing the social‐ecological nature of urban systems. We offer insights and examples, emphasizing the importance of rigorous urban ecological research without imposing constraints on innovation.

Maps of ecosystem service (ES) supply are frequently used to guide spatial planning, policymaking and ecosystem management. However, these are typically based upon coarse land‐cover proxies. This approach lacks a strong mechanistic basis and neglects spatial biodiversity dynamics and interactions among landscape properties that can modify ES provision. We present an analytical framework for ES upscaling that incorporates spatial interactions between landscape properties, which determine ES supply. The resulting models can be viewed as a spatially informed ES production function. Key aspects of our synthetic framework include (i) the systematic assessment of multiple drivers across many levels of abiotic and biotic organization to formulate the statistical ES production function, (ii) the inclusion of spatial interactions with the surrounding environment into the ES production function and (iii) the use of expert input to inform ES production functions. We demonstrate the approach using two example ES from German grasslands: biodiversity conservation and water supply. We show that the inclusion of spatial interactions in the upscaling model improved model predictions by 15%–33%, depending on the ES evaluated. In addition, inclusion of spatial interactions led to reduced error associated with the upscaled estimates. By overcoming several shortcomings of existing upscaling approaches, we generate maps of ES supply that can more reliably inform spatial planning. Further, the underlying models allow for simulation of changes in the drivers of ES supply and estimation of respective outcomes. These advantages have the potential to better link detailed local‐scale ecological understanding and land management with large‐scale ES supply mapping, and thus better inform decision making.

Climate change mitigation and biodiversity conservation are key forest functions, but how to pursue them jointly in timber-managed forests is still unclear. We use a Europe-wide dataset of forest multi-taxon diversity and stand structure to (i) evaluate the importance of aboveground carbon stocks in determining species richness of six taxonomic groups; (ii) assess relationships between species richness and carbon stocks; (iii) discuss the potential to jointly enhance carbon and biodiversity and policy implications. Carbon-diversity relationships are positive for several groups, but mostly when deadwood pools are considered. Forest policies should consider the complex relationship between different carbon pools and taxonomic groups. Environmental policies emphasizing carbon sequestration in aboveground living biomass may conflict with biodiversity conservation by promoting homogeneous, fast-growing forests that fail to support species diversity of multiple groups. Sustainable forest management should acknowledge that deadwood carbon instead may translate into positive outcomes for both carbon storage and biodiversity conservation.

The Triad framework seeks to balance the economic and ecological functions in forested landscapes by combining intensively, extensively, and unmanaged areas, assuming a higher support to biodiversity in extensively rather than in intensively managed forests. We quantified the effects of Triad zoning on biodiversity in (sub)montane eutrophic European beech forests. Using a European-wide multitaxon database and a “virtual” landscape approach (i.e., by resampling empirical data), we evaluated how the proportion of Triad management categories affected the landscape-level species diversity of birds, saproxylic beetles, vascular plants, epiphytic bryophytes, lichens, and wood-inhabiting fungi, as well as multitaxonomic diversity. The results varied greatly among taxonomic groups. Multitaxonomic diversity peaked in landscapes composed of 60% unmanaged and 40% intensively managed forests. While intensive management can benefit some taxa through the creation of open habitats, unmanaged forests are the backbone of biodiversity conservation, underlining the need to safeguard the remaining old-growth forests under natural dynamics, and to extend the current area of unmanaged forests in Europe. Extensive forest management, however, did not contribute to biodiversity conservation as expected. As withdrawing such a high proportion of European forest landscapes from management is unfeasible given the increasing demand for timber, efforts are needed to increase the presence of structural features supporting biodiversity into extensively managed forests.

Maps of ecosystem service (ES) supply are frequently used to guide spatial planning, policy making, and ecosystem management. However, these are typically based upon coarse land-cover proxies. This approach lacks a strong mechanistic basis, and neglects spatial biodiversity dynamics and interactions among landscape properties that can modify ES provision. We present an analytical framework for ES upscaling that incorporates spatial interactions between landscape properties to determine ES supply. The resulting models can be viewed as a spatially informed ES production function. The approach comprises seven steps that include several elements absent from most existing approaches, notably a procedure for identifying geodata variables that represent the true mechanistic drivers, the inclusion of spatial interactions in the upscaling model, and modification following expert feedback on the selected model. We demonstrate the approach using two example ES from German grasslands: biodiversity conservation and water supply. We show that the inclusion of spatial interactions in the upscaling model improved model predictions from 15% to 33% depending on the ES evaluated. In addition, inclusion of spatial interactions led to reduced error associated with the upscaled estimates. By overcoming several shortcomings of existing, upscaling approaches we generate resulting maps of ES supply that can more reliably inform spatial planning Further, the underlying models allow for simulation of changes in the drivers of ES supply and estimation of respective outcomes. These advantages have the potential to better link detailed local-scale ecological understanding and land management with large-scale ES supply mapping, and thus better inform decision making and spatial planning.

Cities are designed primarily for the benefit of humans but also provide habitat for other species. However, understanding how different components of urban vegetation and other features of urban spaces enable different species or species groups to live in the city remains limited. Here we show that, for the City of Munich, designed features of public urban squares strongly determine the occurrence of different species groups. While taxon richness and abundance increased with increasing ‘greenness’ of the square, different taxa responded to different square features, such as the proportion of lawn, the volume of shrubs and the density of trees, as well as the number of people or pets on these squares. Our results highlight that urban design for human needs affects other species that may cohabit these spaces. Consequently, planning strategies for biodiverse cities that aim to enhance human–nature interactions need to be multifaceted, considering the needs of humans and other taxa to create diverse living cities.

In modified production landscapes, biodiversity faces unprecedented pressures from human actions, resulting in significant species declines of plant and animal taxa, including birds. Understanding the underlying mechanisms responsible for such declines is essential to counteract further loss and support practitioners in conserving biodiversity and associated ecosystem function. In this study, we used standardized bird monitoring data collected over 6 years in managed forest and grassland areas across different regions in Germany, Central Europe. We combined these data with morphometric, ecological, behavioral, and acoustic trait data and detailed information on local land use management practices to understand how management decisions affect species and functional diversity, as well as ecological processes shaping local species composition. Our results reveal that the ecosystem and regional context must be considered to understand how management practices affect bird diversity aspects and composition. In forests, regional management decisions related to tree species and stand age affected bird diversity, as well as community and functional composition, and indicated environmental sorting due to ecological and behavioral requirements, biotic interactions, and morphometric constraints. In grasslands, independent of local management practices, increased intensity of land use resulted in an overall loss in bird species richness and functional diversity. Predominantly, constraints due to ecological or behavioral requirements affected bird species assemblage composition. In addition, our results indicated the importance of woody vegetation near managed grasslands and of considering environmental conditions beyond the local scale to support bird diversity and associated ecosystem functions. Our results highlighted that local management decisions can support bird diversity and maintain ecological function. However, this needs a view beyond the local scale of management units. It also demands a joint effort of biologists and land managers to integrate targeted conservation actions into regional management practices and create a network of habitats within production landscapes to protect nature, guard against biotic and functional homogenization, and prevent further degradation of ecosystems in production landscapes.