TY - GEN A1 - Synodinos, Alexios D. A1 - Eldridge, David A1 - Geißler, Katja A1 - Jeltsch, Florian A1 - Lohmann, Dirk A1 - Midgley, Guy A1 - Blaum, Niels T1 - Remotely sensed canopy height reveals three pantropical ecosystem states BT - a comment T2 - Ecology : a publication of the Ecological Society of America Y1 - 2017 U6 - https://doi.org/10.1002/ecy.1997 SN - 0012-9658 SN - 1939-9170 VL - 99 IS - 1 SP - 231 EP - 234 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Muhl, Rika M. W. A1 - Roelke, Daniel L. A1 - Zohary, Tamar A1 - Moustaka-Gouni, Maria A1 - Sommer, Ulrich A1 - Borics, Gabor A1 - Gaedke, Ursula A1 - Withrow, Frances G. A1 - Bhattacharyya, Joydeb T1 - Resisting annihilation BT - relationships between functional trait dissimilarity, assemblage competitive power and allelopathy JF - Ecology letters N2 - Allelopathic species can alter biodiversity. Using simulated assemblages that are characterised by neutrality, lumpy coexistence and intransitivity, we explore relationships between within-assemblage competitive dissimilarities and resistance to allelopathic species. An emergent behaviour from our models is that assemblages are more resistant to allelopathy when members strongly compete exploitatively (high competitive power). We found that neutral assemblages were the most vulnerable to allelopathic species, followed by lumpy and then by intransitive assemblages. We find support for our modeling in real-world time-series data from eight lakes of varied morphometry and trophic state. Our analysis of this data shows that a lake's history of allelopathic phytoplankton species biovolume density and dominance is related to the number of species clusters occurring in the plankton assemblages of those lakes, an emergent trend similar to that of our modeling. We suggest that an assemblage's competitive power determines its allelopathy resistance. KW - Allelopathy KW - exploitative competition KW - interference competition KW - intransitivity KW - lumpy coexistence KW - neutrality KW - species supersaturated assemblages Y1 - 2018 U6 - https://doi.org/10.1111/ele.13109 SN - 1461-023X SN - 1461-0248 VL - 21 IS - 9 SP - 1390 EP - 1400 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - De Lombaerde, Emiel A1 - Verheyen, Kris A1 - Perring, Michael P. A1 - Bernhardt-Roemermann, Markus A1 - Van Calster, Hans A1 - Brunet, Jorg A1 - Chudomelova, Marketa A1 - Decocq, Guillaume A1 - Diekmann, Martin A1 - Durak, Tomasz A1 - Hedl, Radim A1 - Heinken, Thilo A1 - Hommel, Patrick A1 - Jaroszewicz, Bogdan A1 - Kopecky, Martin A1 - Lenoir, Jonathan A1 - Macek, Martin A1 - Máliš, František A1 - Mitchell, Fraser J. G. A1 - Naaf, Tobias A1 - Newman, Miles A1 - Petřík, Petr A1 - Reczyńska, Kamila A1 - Schmidt, Wolfgang A1 - Swierkosz, Krzysztof A1 - Vild, Ondrej A1 - Wulf, Monika A1 - Baetena, Lander T1 - Responses of competitive understorey species to spatial environmental gradients inaccurately explain temporal changes JF - Basic and applied ecology : Journal of the Gesellschaft für Ökologie N2 - Understorey plant communities play a key role in the functioning of forest ecosystems. Under favourable environmental conditions, competitive understorey species may develop high abundances and influence important ecosystem processes such as tree regeneration. Thus, understanding and predicting the response of competitive understorey species as a function of changing environmental conditions is important for forest managers. In the absence of sufficient temporal data to quantify actual vegetation changes, space-for-time (SFT) substitution is often used, i.e. studies that use environmental gradients across space to infer vegetation responses to environmental change over time. Here we assess the validity of such SFT approaches and analysed 36 resurvey studies from ancient forests with low levels of recent disturbances across temperate Europe to assess how six competitive understorey plant species respond to gradients of overstorey cover, soil conditions, atmospheric N deposition and climatic conditions over space and time. The combination of historical and contemporary surveys allows (i) to test if observed contemporary patterns across space are consistent at the time of the historical survey, and, crucially, (ii) to assess whether changes in abundance over time given recorded environmental change match expectations from patterns recorded along environmental gradients in space. We found consistent spatial relationships at the two periods: local variation in soil variables and overstorey cover were the best predictors of individual species’ cover while interregional variation in coarse-scale variables, i.e. N deposition and climate, was less important. However, we found that our SFT approach could not accurately explain the large variation in abundance changes over time. We thus recommend to be cautious when using SFT substitution to infer species responses to temporal changes. KW - Temperate forest KW - Herb layer KW - Tree regeneration KW - Global change KW - Nitrogen deposition KW - Canopy KW - Spatiotemporal resurvey data KW - Cover abundance KW - Chronosequence KW - forestREplot Y1 - 2018 U6 - https://doi.org/10.1016/j.baae.2018.05.013 SN - 1439-1791 SN - 1618-0089 VL - 30 SP - 52 EP - 64 PB - Elsevier GMBH CY - München ER - TY - JOUR A1 - Göritz, Anna A1 - Berger, Stella A. A1 - Gege, Peter A1 - Grossart, Hans-Peter A1 - Nejstgaard, Jens C. A1 - Riedel, Sebastian A1 - Röttgers, Rüdiger A1 - Utschig, Christian T1 - Retrieval of water constituents from hyperspectral in-situ measurements under variable cloud cover BT - a case study at Lake Stechlin (Germany) JF - Remote sensing / Molecular Diversity Preservation International (MDPI) N2 - Remote sensing and field spectroscopy of natural waters is typically performed under clear skies, low wind speeds and low solar zenith angles. Such measurements can also be made, in principle, under clouds and mixed skies using airborne or in-situ measurements; however, variable illumination conditions pose a challenge to data analysis. In the present case study, we evaluated the inversion of hyperspectral in-situ measurements for water constituent retrieval acquired under variable cloud cover. First, we studied the retrieval of Chlorophyll-a (Chl-a) concentration and colored dissolved organic matter (CDOM) absorption from in-water irradiance measurements. Then, we evaluated the errors in the retrievals of the concentration of total suspended matter (TSM), Chl-a and the absorption coefficient of CDOM from above-water reflectance measurements due to highly variable reflections at the water surface. In order to approximate cloud reflections, we extended a recent three-component surface reflectance model for cloudless atmospheres by a constant offset and compared different surface reflectance correction procedures. Our findings suggest that in-water irradiance measurements may be used for the analysis of absorbing compounds even under highly variable weather conditions. The extended surface reflectance model proved to contribute to the analysis of above-water reflectance measurements with respect to Chl-a and TSM. Results indicate the potential of this approach for all-weather monitoring. KW - remote sensing KW - inland water KW - hyperspectral measurements KW - in-situ KW - cloud KW - surface reflection KW - inversion KW - bio-optical modeling Y1 - 2018 U6 - https://doi.org/10.3390/rs10020181 SN - 2072-4292 VL - 10 IS - 2 PB - MDPI CY - Basel ER - TY - JOUR A1 - van Velzen, Ellen A1 - Gaedke, Ursula T1 - Reversed predator BT - prey cycles are driven by the amplitude of prey oscillations JF - Ecology and Evolution N2 - Ecoevolutionary feedbacks in predator–prey systems have been shown to qualitatively alter predator–prey dynamics. As a striking example, defense–offense coevolution can reverse predator–prey cycles, so predator peaks precede prey peaks rather than vice versa. However, this has only rarely been shown in either model studies or empirical systems. Here, we investigate whether this rarity is a fundamental feature of reversed cycles by exploring under which conditions they should be found. For this, we first identify potential conditions and parameter ranges most likely to result in reversed cycles by developing a new measure, the effective prey biomass, which combines prey biomass with prey and predator traits, and represents the prey biomass as perceived by the predator. We show that predator dynamics always follow the dynamics of the effective prey biomass with a classic ¼‐phase lag. From this key insight, it follows that in reversed cycles (i.e., ¾‐lag), the dynamics of the actual and the effective prey biomass must be in antiphase with each other, that is, the effective prey biomass must be highest when actual prey biomass is lowest, and vice versa. Based on this, we predict that reversed cycles should be found mainly when oscillations in actual prey biomass are small and thus have limited impact on the dynamics of the effective prey biomass, which are mainly driven by trait changes. We then confirm this prediction using numerical simulations of a coevolutionary predator–prey system, varying the amplitude of the oscillations in prey biomass: Reversed cycles are consistently associated with regions of parameter space leading to small‐amplitude prey oscillations, offering a specific and highly testable prediction for conditions under which reversed cycles should occur in natural systems. KW - coevolution KW - ecoevolutionary dynamics KW - predator-prey dynamics KW - top-down control Y1 - 2018 U6 - https://doi.org/10.1002/ece3.4184 SN - 2045-7758 SP - 1 EP - 13 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - van Velzen, Ellen A1 - Gaedke, Ursula T1 - Reversed predator-prey cycles are driven by the amplitude of prey oscillations JF - Ecology and evolution N2 - Ecoevolutionary feedbacks in predator-prey systems have been shown to qualitatively alter predator-prey dynamics. As a striking example, defense-offense coevolution can reverse predator-prey cycles, so predator peaks precede prey peaks rather than vice versa. However, this has only rarely been shown in either model studies or empirical systems. Here, we investigate whether this rarity is a fundamental feature of reversed cycles by exploring under which conditions they should be found. For this, we first identify potential conditions and parameter ranges most likely to result in reversed cycles by developing a new measure, the effective prey biomass, which combines prey biomass with prey and predator traits, and represents the prey biomass as perceived by the predator. We show that predator dynamics always follow the dynamics of the effective prey biomass with a classic 1/4-phase lag. From this key insight, it follows that in reversed cycles (i.e., -lag), the dynamics of the actual and the effective prey biomass must be in antiphase with each other, that is, the effective prey biomass must be highest when actual prey biomass is lowest, and vice versa. Based on this, we predict that reversed cycles should be found mainly when oscillations in actual prey biomass are small and thus have limited impact on the dynamics of the effective prey biomass, which are mainly driven by trait changes. We then confirm this prediction using numerical simulations of a coevolutionary predator-prey system, varying the amplitude of the oscillations in prey biomass: Reversed cycles are consistently associated with regions of parameter space leading to small-amplitude prey oscillations, offering a specific and highly testable prediction for conditions under which reversed cycles should occur in natural systems. KW - coevolution KW - ecoevolutionary dynamics KW - predator-prey dynamics KW - top-down control Y1 - 2018 U6 - https://doi.org/10.1002/ece3.4184 SN - 2045-7758 VL - 8 IS - 12 SP - 6317 EP - 6329 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Manzoni, Stefano A1 - Capek, Petr A1 - Porada, Philipp A1 - Thurner, Martin A1 - Winterdahl, Mattias A1 - Beer, Christian A1 - Bruchert, Volker A1 - Frouz, Jan A1 - Herrmann, Anke M. A1 - Lindahl, Bjorn D. A1 - Lyon, Steve W. A1 - Šantrůčková, Hana A1 - Vico, Giulia A1 - Way, Danielle T1 - Reviews and syntheses BT - Carbon use efficiency from organisms to ecosystems - definitions, theories, and empirical evidence JF - Biogeosciences N2 - The cycling of carbon (C) between the Earth surface and the atmosphere is controlled by biological and abiotic processes that regulate C storage in biogeochemical compartments and release to the atmosphere. This partitioning is quantified using various forms of C-use efficiency (CUE) - the ratio of C remaining in a system to C entering that system. Biological CUE is the fraction of C taken up allocated to biosynthesis. In soils and sediments, C storage depends also on abiotic processes, so the term C-storage efficiency (CSE) can be used. Here we first review and reconcile CUE and CSE definitions proposed for autotrophic and heterotrophic organisms and communities, food webs, whole ecosystems and watersheds, and soils and sediments using a common mathematical framework. Second, we identify general CUE patterns; for example, the actual CUE increases with improving growth conditions, and apparent CUE decreases with increasing turnover. We then synthesize > 5000CUE estimates showing that CUE decreases with increasing biological and ecological organization - from uni-cellular to multicellular organisms and from individuals to ecosystems. We conclude that CUE is an emergent property of coupled biological-abiotic systems, and it should be regarded as a flexible and scale-dependent index of the capacity of a given system to effectively retain C. Y1 - 2018 U6 - https://doi.org/10.5194/bg-15-5929-2018 SN - 1726-4170 SN - 1726-4189 VL - 15 IS - 19 SP - 5929 EP - 5949 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - He, Hai A1 - Edlich-Muth, Christian A1 - Lindner, Steffen N. A1 - Bar-Even, Arren T1 - Ribulose Monophosphate Shunt Provides Nearly All Biomass and Energy Required for Growth of E. coli JF - ACS Synthetic Biology N2 - The ribulose monophosphate (RuMP) cycle is a highly efficient route for the assimilation of reduced one-carbon compounds. Despite considerable research, the RuMP cycle has not been fully implemented in model biotechnological organisms such as Escherichia coli, mainly since the heterologous establishment of the pathway requires addressing multiple challenges: sufficient formaldehyde production, efficient formaldehyde assimilation, and sufficient regeneration of the formaldehyde acceptor, ribulose 5-phosphate. Here, by efficiently producing formaldehyde from sarcosine oxidation and ribulose 5-phosphate from exogenous xylose, we set aside two of these concerns, allowing us to focus on the particular challenge of establishing efficient formaldehyde assimilation via the RuMP shunt, the linear variant of the RuMP cycle. We have generated deletion strains whose growth depends, to different extents, on the activity of the RuMP shunt, thus incrementally increasing the selection pressure for the activity of the synthetic pathway. Our final strain depends on the activity of the RuMP shunt for providing the cell with almost all biomass and energy needs, presenting an absolute coupling between growth and activity of key RuMP cycle components. This study shows the value of a stepwise problem solving approach when establishing a difficult but promising pathway, and is a strong basis for future engineering, selection, and evolution of model organisms for growth via the RuMP cycle. KW - ribulose monophosphate cycle KW - methylotrophy KW - metabolic engineering KW - growth selection KW - carbon labeling KW - flux modeling KW - formaldehyde assimilation Y1 - 2018 U6 - https://doi.org/10.1021/acssynbio.8b00093 SN - 2161-5063 VL - 7 IS - 6 SP - 1601 EP - 1611 PB - ACS CY - Washington, DC ER - TY - JOUR A1 - Schwanhold, Nadine A1 - Iobbi-Nivol, Chantal A1 - Lehmann, Angelika A1 - Leimkühler, Silke T1 - Same but different BT - Comparison of two system-specific molecular chaperones for the maturation of formate dehydrogenases JF - PLoS one N2 - The maturation of bacterial molybdoenzymes is a complex process leading to the insertion of the bulky bis-molybdopterin guanine dinucleotide (bis-MGD) cofactor into the apoenzyme. Most molybdoenzymes were shown to contain a specific chaperone for the insertion of the bis-MGD cofactor. Formate dehydrogenases (FDH) together with their molecular chaperone partner seem to display an exception to this specificity rule, since the chaperone FdhD has been proven to be involved in the maturation of all three FDH enzymes present in Escherichia colt. Multiple roles have been suggested for FdhD-like chaperones in the past, including the involvement in a sulfur transfer reaction from the L-cysteine desulfurase IscS to bis-MGD by the action of two cysteine residues present in a conserved CXXC motif of the chaperones. However, in this study we show by phylogenetic analyses that the CXXC motif is not conserved among FdhD-like chaperones. We compared in detail the FdhD-like homologues from Rhodobacter capsulatus and E. colt and show that their roles in the maturation of FDH enzymes from different subgroups can be exchanged. We reveal that bis-MGDbinding is a common characteristic of FdhD-like proteins and that the cofactor is bound with a sulfido-ligand at the molybdenum atom to the chaperone. Generally, we reveal that the cysteine residues in the motif CXXC of the chaperone are not essential for the production of active FDH enzymes. Y1 - 2018 U6 - https://doi.org/10.1371/journal.pone.0201935 SN - 1932-6203 VL - 13 IS - 11 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Yannelli, Florencia A. A1 - Karrer, Gerhard A1 - Hall, Rea A1 - Kollmann, Johannes A1 - Heger, Tina T1 - Seed density is more effective than multi-trait limiting similarity in controlling grassland resistance against plant invasions in mesocosms JF - Applied vegetation science : official organ of the International Association for Vegetation Science N2 - QuestionDisturbed areas offer great opportunities for restoring native biodiversity, but they are also prone to invasion by alien plants. Following the limiting similarity hypothesis, we address the question of whether or not similarity of plant functional traits helps developing seed mixtures of native communities with high resistance to invasive species at an early stage of restoration. LocationCentre of Greenhouses and Laboratories Durnast, Technische Universitat Munchen, Freising, Germany. MethodsUsing a system of linear equations, we designed native communities maximizing the similarity between the native and two invasive species according to ten functional traits. We used native grassland plants, two invasive alien species that are often problematic in disturbed areas (i.e., Ambrosia artemisiifolia and Solidago gigantea) and trait information obtained from databases. The two communities were then tested for resistance against establishment of the two invaders separately in a greenhouse experiment. We measured height of the invasive species and above-ground biomass, along with leaf area index, 4 and 8months after sowing respectively. ResultsBoth invasive species were successfully reduced by the native community designed to suppress S. gigantea dominated by small-seeded species. These results could be considered as partial support for the limiting similarity hypothesis. However, given the success of this mixture against both invasive species, suppression was better explained by a seed density effect resulting from the smaller seed mass of the native species included in this mixture. Further, the dominance of a fast-developing competitive species could also contribute to its success. ConclusionsThere was no unequivocal support for the limiting similarity hypothesis in terms of the traits selected. Instead we found that increasing seeding density of native species and selecting species with a fast vegetative development is an effective way to suppress invasive plants during early stages of restoration. If limiting similarity is used to design communities for restoration, early life-history traits should be taken into account. KW - Achillea millefolium KW - Ambrosia artemisiifolia KW - biotic resistance KW - competition KW - density-driven suppression KW - disturbed areas KW - restoration KW - seed mixtures KW - Solidago gigantea Y1 - 2018 U6 - https://doi.org/10.1111/avsc.12373 SN - 1402-2001 SN - 1654-109X VL - 21 IS - 3 SP - 411 EP - 418 PB - Wiley CY - Hoboken ER -