@misc{HuettlGerwin, author = {H{\"u}ttl, Reinhard F. and Gerwin, Werner}, title = {Landscape Development From Point Zero}, series = {Pacific Science}, volume = {77}, journal = {Pacific Science}, number = {2-3}, issn = {1534-6188}, doi = {10.2984/77.2.11}, pages = {309 -- 325}, abstract = {Severe disturbances of landscapes entail an ecosystem development with the formation of structures and functions which may reach either a new equilibrium state or a state similar to the original ecosystem. Natural disturbances can result from major events such as volcanoes, glaciers, or denudations from landslides. Major disturbance may also evolve from anthropogenic influences such as from mining operations. They all can be considered starting points for the development of ecosystems from 'point zero', which was one central research interest of Dieter Mueller-Dombois. In this paper results from research in the Lusatian post-mining landscapes (Eastern Germany) are presented. Different methodological approaches are discussed. The well-defined 'point zero' of the ecosystem development allows for research on chronosequence designs as well as real time series studies. Chronosequences have been investigated to gain insight into the medium to long-term direction of the development. Real time series are recorded to obtain a more detailed understanding. The paper is structured into three main parts: First, effects of ecosystem disturbances by mining in Lusatia and the initial conditions for restoration are presented. In the following part practical rehabilitation measures and land use options are discussed. Finally, the third part summarizes results of long-term monitoring in an artificial watershed. In conclusion, post-mining landscapes allow for relevant case studies of ecosystem development after severe disturbances. Particularly, the starting point of the initial phase is very well defined which distinguishes these anthropogenically disturbed landscapes from landscapes after natural disturbances.}, language = {en} } @misc{MajauraBoehmFreese, author = {Majaura, Marie and B{\"o}hm, Christian and Freese, Dirk}, title = {The Influence of Trees on Crop Yields in Temperate Zone Alley Cropping Systems: A Review}, series = {Sustainability}, volume = {16}, journal = {Sustainability}, number = {8}, issn = {2071-1050}, doi = {10.3390/su16083301}, language = {en} } @incollection{VesteSheppardAbdulaietal., author = {Veste, Maik and Sheppard, Jonathan P. and Abdulai, Issaka and Ayisi, Kwabena K. and Borrass, Lars and Chirwa, Paxie W. and Funk, Roger}, title = {The Need for Sustainable Agricultural Land-Use Systems: Benefits from Integrated Agroforestry Systems}, series = {Sustainability of Southern African Ecosystems under Global Change}, booktitle = {Sustainability of Southern African Ecosystems under Global Change}, editor = {Maltitz, Graham P. von and Midgley, Guy F. and Veitch, Jennifer and Br{\"u}mmer, Christian and R{\"o}tter, Reimund P. and Viehberg, Finn A. and Veste, Maik}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-10947-8}, doi = {10.1007/978-3-031-10948-5_21}, pages = {587 -- 623}, abstract = {This chapter introduces the different agroforestry systems (AFSs) as part of the diversification of agricultural landscapes and gives examples of their use in different related crop production systems in southern Africa. The introduction of trees into agriculture has several benefits and can mitigate the effects of climate change. For example nitrogen-fixing trees and shrubs contribute significantly to nutrient recycling and benefit soil conservation, which is particularly important for smallholder farms. In addition, shelterbelts play an important role in reducing wind speeds, and thus, evapotranspiration, and modifying the microclimatic conditions, which is an important factor for the adaptation of cropping systems to climate change. These integrated AFS landscapes provide important ecosystem services for soil protection, food security and for biodiversity. However, deficiencies in the institutional and policy frameworks that underlie the adoption and stimulus of AFS in the southern African region were identified. Furthermore, the following factors must be considered to optimise AFS: (1) selection of tree species that ensure maximum residual soil fertility beyond 3 years, (2) size of land owned by the farmer, (3) integrated nutrition management, where organic resources are combined with synthetic inorganic fertilisers and (4) tree-crop competition in the root zone for water.}, language = {en} } @misc{OPUS4-32578, title = {Sustainability of Southern African Ecosystems under Global Change}, editor = {Maltitz, Graham P. von and Midgley, Guy F. and Veitch, Jennifer and Br{\"u}mmer, Christian and R{\"o}tter, Reimund P. and Viehberg, Finn A. and Veste, Maik}, edition = {1. Auflage}, publisher = {Spinger}, address = {Heidelberg}, isbn = {978-3-031-10947-8}, doi = {10.1007/978-3-031-10948-5}, pages = {XXXV, 973}, abstract = {This open access book about the sustainability of marine and terrestrial ecosystems in southern Africa provides a synthesis of the research program Science Partnerships for the Adaptation to Complex Earth System Processes (SPACES II, 2018-2022). It addresses the scientific, social, and economic issues related to climate change, its potential impacts on the various ecosystems, adaptations, and management interventions for enhancing systems resilience in Southern Africa. It is written by numerous scientists from African states and Germany and summarizes the latest research findings, which are of great relevance for a better understanding of climate change impacts, adaptations, and vulnerabilities as well as for developing management options and policy options to reduce the associated risks. This is crucial considering that the projected African population increase is exceptional. Furthermore, climate change is assumed to hit southern Africa extremely hard with a significant increase in extreme events and the frequency of severe droughts, heat waves, and flooding. Southern Africa hosts a high variety of ecosystems, which belongs to important biodiversity hotspots for unique flora and fauna. The surrounding oceans form, in turn, a bottle neck within the ocean's global thermohaline circulation, act as a still poorly understood carbon sink and source and play an important role for fisheries as they are highly productive. Considering these important aspects, the book is an important interdisciplinary contribution to the scientific literature and will find a wide readership. The book is aimed at students, teachers, and scientists in the fields of terrestrial and marine ecology, environmental, nature and landscape planning, agriculture, environmental and resource management, biodiversity, and nature conservation, as well as scientists and representatives in specialised authorities and associations, nature conservationists, and policy makers of related disciplines.}, language = {en} } @incollection{RoetterNkomoMeyerzuDreweretal., author = {R{\"o}tter, Reimund P. and Nkomo, Mandla and Meyer zu Drewer, Johannes and Veste, Maik}, title = {Agricultural Land-Use Systems and Management Challenges}, series = {Sustainability of Southern African Ecosystems under Global Change}, booktitle = {Sustainability of Southern African Ecosystems under Global Change}, editor = {Maltitz, Graham P. von and Midgley, Guy F. and Veitch, Jennifer and Br{\"u}mmer, Christian and Viehberg, Finn A. and Veste, Maik}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-10947-8}, doi = {10.1007/978-3-031-10948-5_20}, pages = {551 -- 586}, abstract = {This chapter aims at providing an overview of the diversity of agroecological conditions, features of main farming systems, agricultural land use, its dynamics and drivers during the last two decades as well as major threats in ten countries of southern Africa (SA10). Based on this, we attempt to identify the resultant challenges for sustainable land management and outline potential interventions with a focus on smallholder farmers. By analyzing cropland dynamics during 2000-2019, we show how land use has been shaped by climate, demographic development, economic imperatives and policy realities. Concrete examples of these complex interactions illustrate both considerable shrinkage in South Africa and Zimbabwe or expansion of cropland in Mozambique and Zambia. During the past 20 years, cropland increased by 37\% on average across SA10 mainly at the expense of forestland—showing huge spatiotemporal heterogeneity among countries. Most smallholders face shrinking farm size and other resource limitations that have resulted in soil nutrient mining and low agricultural productivity—a highly unsustainable situation. We conclude with an outlook on potential transformation pathways ("TechnoGarden" and "AdaptiveMosaic") for the near future and thereby provide a frame for further studies on sustainable land management options under given local settings.}, language = {en} } @incollection{MaltitzBieriMidgleyetal., author = {Maltitz, Graham P. von and Bieri, Mari and Midgley, Guy F. and Veitch, Jennifer and Br{\"u}mmer, Christian and R{\"o}tter, Reimund P. and Veste, Maik}, title = {Coupled Earth System and Human Processes: An Introduction to SPACES and the Book}, series = {Sustainability of Southern African Ecosystems under Global Change}, booktitle = {Sustainability of Southern African Ecosystems under Global Change}, editor = {Maltitz, Graham P. von and Midgley, Guy F. and Veitch, Jennifer and Br{\"u}mmer, Christian and R{\"o}tter, Reimund P. and Viehberg, Finn A. and Veste, Maik}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-10947-8}, doi = {10.1007/978-3-031-10948-5}, pages = {3 -- 21}, abstract = {Ecosystems in southern Africa are threatened by numerous global change forces, with climate change being a major threat to the region. Many climate change impacts and environmental-based mitigation and adaptation options remain poorly researched in this globally important biodiversity hotspot. This book is a collection of chapters covering research undertaken in southern Africa by the German Federal Ministry of Education and Research's (BMBF) SPACES and SPACES II programs. SPACES II covered a wide range of global change-linked environmental issues ranging in scope from the impacts of ocean currents on global climate systems through to understanding how small-scale farmers may best adapt to the impacts of climate change. All the research has identified policy implications, and the book strives for a balance between presenting the detailed science underpinning the conclusions as well as providing clear and simple policy messages. To achieve this, many chapters in the book contextualize the issues through the provision of a mini-review and combine this with the latest science emulating out of the SPACES II program of research. The book therefore consolidated both past and the most current research findings in a way that will be of benefit to both academia and policy makers.}, language = {en} } @incollection{MaltitzMidgleyVeitchetal., author = {Maltitz, Graham P. von and Midgley, Guy F. and Veitch, Jennifer and Br{\"u}mmer, Christian and R{\"o}tter, Reimund P. and Rixen, Tim and Brandt, Peter and Veste, Maik}, title = {Synthesis and Outlook on Future Research and Scientific Education in Southern Africa}, series = {Sustainability of Southern African Ecosystems under Global Change}, booktitle = {Sustainability of Southern African Ecosystems under Global Change}, editor = {Maltitz, Graham P. von and Midgley, Guy F. and Veitch, Jennifer and Br{\"u}mmer, Christian and R{\"o}tter, Reimund P. and Viehberg, Finn A. and Veste, Maik}, publisher = {Springer}, address = {Cham}, isbn = {978-3-031-10947-8}, doi = {10.1007/978-3-031-10948-5_32}, pages = {933 -- 964}, abstract = {The sustainability of southern Africa's natural and managed marine and terrestrial ecosystems is threatened by overuse, mismanagement, population pressures, degradation, and climate change. Counteracting unsustainable development requires a deep understanding of earth system processes and how these are affected by ongoing and anticipated global changes. This information must be translated into practical policy and management interventions. Climate models project that the rate of terrestrial warming in southern Africa is above the global terrestrial average. Moreover, most of the region will become drier. Already there is evidence that climate change is disrupting ecosystem functioning and the provision of ecosystem services. This is likely to continue in the foreseeable future, but impacts can be partly mitigated through urgent implementation of appropriate policy and management interventions to enhance resilience and sustainability of the ecosystems. The recommendations presented in the previous chapters are informed by a deepened scientific understanding of the relevant earth system processes, but also identify research and knowledge gaps. Ongoing disciplinary research remains critical, but needs to be complemented with cross-disciplinary and transdisciplinary research that can integrate across temporal and spatial scales to give a fuller understanding of not only individual components of the complex earth-system, but how they interact.}, language = {en} } @misc{FischerKholiavkoSchaafetal., author = {Fischer, Thomas and Kholiavko, Tatiana and Schaaf, Wolfgang and Veste, Maik}, title = {Soil respiration responses of moss and lichen biocoenoses to moderate and severe rain events after summer drought in a temperate early-successional ecosystem}, series = {Ecohydrology}, volume = {16}, journal = {Ecohydrology}, number = {7}, issn = {1936-0592}, doi = {10.1002/eco.2578}, abstract = {It is commonly accepted that CO2 efflux increases with soil water content in aerated soils and that rewetting after periods of soil drying can result in respiration pulses. It has further been shown that soil pores may become water logged which can impede soil gas exchange. The present study aimed to quantify the carbon response of moss (Polytrichum piliferum) and lichen (Cladonia coniocraea) biocoenoses to different quantities of rain in an artificial catchment, which granted that the starting point of the development of both biocoenoses was the same. To address this aim, we conducted in situ soil moisture and soil respiration measurements, where soil respiration was hypothesised to emerge from a cryptogamic vegetation layer and from mineral soil beneath. We found that higher water-holding capacity of the moss layer and higher accumulation of organic matter in the upper mineral soil under mosses result in higher amounts of water stored near the surface. As a consequence, evaporation of water as well as pulses of CO2 efflux after moderate rain following a period of drought were higher in the moss biocoenosis, where the upper mineral soil was of key importance. In contrast, the lichen biocoenosis facilitated penetration of rainwater into the deep soil. Superimposing rewetting pulses, near-saturation of soil pores with water after severe rain resulted in gas exchange inhibition and diminished soil respiration until subsequent aeration in both biocoenoses}, language = {en} } @misc{MaWeberKratzetal., author = {Ma, Yunyao and Weber, Bettina and Kratz, Alexandra and Raggio, Jos{\´e} and Colesie, Claudia and Veste, Maik and Bader, Maaike Y. and Porada, Philipp}, title = {Exploring environmental and physiological drivers of the annual carbon budget of biocrusts from various climatic zones with a mechanistic data-driven model}, series = {Biogeosciences}, volume = {20}, journal = {Biogeosciences}, number = {13}, issn = {1726-4189}, doi = {10.5194/bg-20-2553-2023}, pages = {2553 -- 2572}, abstract = {Biocrusts are a worldwide phenomenon, contributing substantially to ecosystem functioning. Their growth and survival depend on multiple environmental factors, including climatic ones, and the relations of these factors to physiological processes. Responses of biocrusts to individual environmental factors have been examined in a large number of field and laboratory experiments. These observational data, however, have rarely been assembled into a comprehensive, consistent framework that allows quantitative exploration of the roles of multiple environmental factors and physiological properties for the performance of biocrusts, in particular across climatic regions. Here we used a data-driven mechanistic modelling framework to simulate the carbon balance of biocrusts, a key measure of their growth and survival. We thereby assessed the relative importance of physiological and environmental factors for the carbon balance at six study sites that differ in climatic conditions. Moreover, we examined the role of seasonal acclimation of physiological properties using our framework, since the effects of this process on the carbon balance of biocrusts are poorly constrained so far. We found substantial effects of air temperature, CO2 concentration, and physiological parameters that are related to respiration on biocrust carbon balance, which differ, however, in their patterns across regions. The ambient CO2 concentration is the most important factor for biocrusts from drylands, while air temperature has the strongest impact at alpine and temperate sites. Metabolic respiration cost plays a more important role than optimum temperature for gross photosynthesis at the alpine site; this is not the case, however, in drylands and temperate regions. Moreover, we estimated a small annual carbon gain of 1.5  by lichen-dominated biocrust and 1.9  by moss-dominated biocrust at a dryland site, while the biocrusts lost a large amount of carbon at some of the temperate sites (e.g. -92.1 for lichen-dominated and -74.7  for moss-dominated biocrust). These strongly negative values contradict the observed survival of the organisms at the sites and may be caused by the uncertainty in environmental conditions and physiological parameters, which we assessed in a sensitivity analysis. Another potential explanation for this result may be the lack of acclimation in the modelling approach, since the carbon balance can increase substantially when testing for seasonally varying parameters in the sensitivity analysis. We conclude that the uncertainties in air temperature, CO2 concentration, respiration-related physiological parameters, and the absence of seasonal acclimation in the model for humid temperate and alpine regions may be a relevant source of error and should be taken into account in future approaches that aim at estimating the long-term biocrust carbon balance based on ecophysiological data.}, language = {en} } @misc{OpreiSchreckingerKholiavkoetal., author = {Oprei, Anna and Schreckinger, Jos{\´e} and Kholiavko, Tatiana and Frossard, Aline and Mutz, Michael and Risse-Buhl, Ute}, title = {Long-term functional recovery and associated microbial community structure after sediment drying and bedform migration}, series = {Frontiers in Ecology and Evolution}, volume = {Vol. 11}, journal = {Frontiers in Ecology and Evolution}, issn = {2296-701X}, doi = {10.3389/fevo.2023.1112519}, abstract = {Climate change and erosion from agricultural areas cause increased drying periods and bedform migration of riverbeds, respectively, worldwide. Both sediment drying and bedform migration can independently stress the microbial community residing in the riverbed. Here, we investigated the microbial response after exposure to these stressors with a focus on long-term recovery. We conducted an in situ experiment to investigate the long-term (8 months) functional and structural recovery of benthic microbial communities from either sediment drying (episodic severe stressor) or bedform migration (frequent moderate stressor). Stressed sediment associated communities were rewetted (dried sediments) and immobilized (migrated sediments) and exposed in the River Spree (north-eastern Germany) to initiate the recovery process. We then evaluated the microbial function (community respiration, net community production and extracellular enzymatic activities) as well as the bacterial, fungal and diatom community structure (16S rRNA gene and ITS region metabarcoding, and microscopic diatom morphotype classification). We observed different recovery times for community respiration (less than 7 days) and gross primary production (more than 5 months), implying a shift toward net heterotrophy in the first few months after stress exposure. Similarly, we observed a strong autotrophic community response (particularly associated with the diatoms Navicula and Fragilaria), especially in migrated sediments. The bacterial and fungal community response to sediment drying was stronger than to bedform migration (particularly associated with the bacterium Flavobacterium and the fungi Alternaria sp. and Aureobasidium pullulans). Our results show that sediment drying and bedform migration had a significant impact on the microbial community function and structure, which persisted for several months after the stress. Due to the surprising long period of recovery, successive stress events combined with seasonal effects will likely hamper the ongoing recovery process with severe alterations to the microbial function and structure. These findings extend the concept of ecosystem resilience and stability on the dimensions of timescale and seasonal environmental variations. Legacy effects are expected to play a key role when facing future stress.}, language = {en} }