TY - JOUR A1 - Thierbach, René A1 - Drewes, Gunnar A1 - Fusser, Markus A1 - Wolfrum, Kathrin A1 - Epe, Bernd A1 - Ristow, Michael A1 - Steinberg, Pablo T1 - A role for iron-sulfur cluster proteins in DNA repair Y1 - 2009 UR - http://www.springerlink.com/content/100530 U6 - https://doi.org/10.1007/s00210-009-0404-1 SN - 0028-1298 ER - TY - JOUR A1 - Thierbach, René A1 - Blume, Urte A1 - Wolfrum, K. A1 - Drewes, Gunnar A1 - Voigt, Anja A1 - Ristow, Michael A1 - Steinberg, Pablo T1 - Altered carbohydrate metabolism in a tumour developing knock-out mice model Y1 - 2010 UR - http://www.springerlink.com/content/100530 U6 - https://doi.org/10.1007/s00210-010-0508-7 SN - 0028-1298 ER - TY - JOUR A1 - Ristow, Michael T1 - Anmerkung zum Verwandtschaftskreis des Ornithogalum umbellatum L. in Brandenburg Y1 - 2001 ER - TY - JOUR A1 - Ristow, Michael T1 - Anmerkungen zur Gattung Koeleria in Brandenburg Y1 - 2001 ER - TY - JOUR A1 - Fischer, Wolfgang A1 - Ristow, Michael T1 - Bericht über die 31. Brandenburgische Botanikertagung vom 23. bis 26. Juni 2000 in Linowsee bei Rheinsberg Y1 - 2002 ER - TY - JOUR A1 - Ristow, Michael T1 - Bericht über die 32. Brandenburgische Botanikertagung vom 29. Juni bis 2. Juli 2001 am Üdersee bei Eberswalde. Y1 - 2003 ER - TY - JOUR A1 - Hanspach, Dietrich A1 - Ristow, Michael T1 - Bericht über die 34. Brandenburgische Botanikertagung vom 20. bis 23. Juni 2003 in Ortrand Y1 - 2005 ER - TY - JOUR A1 - Rohner, Ria A1 - Ristow, Michael T1 - Ein isoliertes Vorkommen kontinentaler Trockenrasen-Pflanzen in den Gorrenbergen bei Medewitz (Hoher Fläming) Y1 - 2005 ER - TY - JOUR A1 - Bergholz, Kolja A1 - May, Felix A1 - Giladi, Itamar A1 - Ristow, Michael A1 - Ziv, Yaron A1 - Jeltsch, Florian T1 - Environmental heterogeneity drives fine-scale species assembly and functional diversity of annual plants in a semi-arid environment JF - Perspectives in plant ecology, evolution and systematics N2 - Spatial environmental heterogeneity is considered a fundamental factor for the maintenance of plant species richness. However, it still remains unclear whether heterogeneity may also facilitate coexistence at fine grain sizes or whether other processes, like mass effects and source sink dynamics due to dispersal, control species composition and diversity at these scales. In this study, we used two complimentary analyses to identify the role of heterogeneity within 15 m x 15 m plots for the coexistence of species-rich annual communities in a semi-arid environment along a steep precipitation gradient. Specifically, we: (a) analyzed the effect of environmental heterogeneity on species, functional and phylogenetic diversity within microsites (alpha diversity, 0.06 m(2) and 1 m(2)), across microsites (beta diversity), and diversity at the entire plot (gamma diversity); (b) further we used two null models to detect non-random trait and phylogenetic patterns in order to infer assembly processes, i.e. whether co-occurring species tend to share similar traits (trait convergence) or dissimilar traits (trait divergence). In general, our results showed that heterogeneity had a positive effect on community diversity. Specifically, for alpha diversity, the effect was significant for functional diversity, and not significant for either species or phylogenetic diversities. For beta diversity, all three measures of community diversity (species, functional, and phylogenetic) increased significantly, as they also did for gamma diversity, where functional measures were again stronger than for species or phylogenetic measures. In addition, the null model approach consistently detected trait convergence, indicating that species with similar traits tended to co-occur and had high abundances in a given microsite. While null model analysis across the phylogeny partly supported these trait findings, showing phylogenetic underdispersion at the 1m(2) grain size, surprisingly when species abundances in microsites were analyzed they were more evenly distributed across the phylogenetic tress than expected (phylogenetic overdispersion). In conclusion, our results provide compelling support that environmental heterogeneity at a relatively fine scale is an important factor for species co-existence as it positively affects diversity as well as influences species assembly. Our study underlines the need for trait-based approaches conducted at fine grain sizes in order to better understand species coexistence and community assembly. (C) 2017 Elsevier GmbH. All rights reserved. KW - Community assembly KW - Plant functional trait KW - Habitat heterogeneity KW - Limiting similarity KW - Environmental filtering KW - Heterogeneity species diversity relationship Y1 - 2017 U6 - https://doi.org/10.1016/j.ppees.2017.01.001 SN - 1433-8319 VL - 24 SP - 138 EP - 146 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Von Raab-Straube, Eckhard A1 - Raus, Thomas A1 - Bazos, Ioannis A1 - Cornec, J. P. A1 - De Belair, Gerard. A1 - Dimitrakopoulos, P. G. A1 - El Mokni, Ridha A1 - Fateryga, Alexander V. A1 - Fateryga, Valentina V. A1 - Fridlender, Alain A1 - Gil, Jaime A1 - Grigorenko, V. N. A1 - Hand, Ralf A1 - Kovalchuk, A. A1 - Mastrogianni, A. A1 - Otto, R. A1 - Rätzel, Stefan A1 - Raus, Th. A1 - Ristow, Michael A1 - Salas Pascual, M. A1 - Strid, Arne A1 - Svirin, S. A. A1 - Tsiripidis, Ioannis. A1 - Uhlich, Holger A1 - Vela, Errol A1 - Verloove, Filip A1 - Vidakis, K. A1 - Yena, Andriy Vasylyovych A1 - Yevseyenkov, P. E. A1 - Zeddam, A. T1 - Euro plus Med-Checklist Notulae, 11 JF - Willdenowia N2 - This is the eleventh of a series of miscellaneous contributions, by various authors, where hitherto unpublished data relevant to both the Med-Checklist and the Euro+Med (or Sisyphus) projects are presented. This instalment deals with the families Anacardiaceae, Asparagaceae (incl. Hyacinthaceae), Bignoniaceae, Cactaceae, Compositae, Cruciferae, Cyperaceae, Ericaceae, Gramineae, Labiatae, Leguminosae, Orobanchaceae, Polygonaceae, Rosaceae, Solanaceae and Staphyleaceae. It includes new country and area records and taxonomic and distributional considerations for taxa in Bidens, Campsis, Centaurea, Cyperus, Drymocallis, Engem, Hoffmannseggia, Hypopitys, Lavandula, Lithraea, Melilotus, Nicotiana, Olimarabidopsis, Opuntia, Orobanche, Phelipanche, Phragmites, Rumex, Salvia, Schinus, Staphylea, and a new combination in Drimia. KW - distribution KW - Euro plus Med PlantBase KW - Europe KW - Med-Checklist KW - Mediterranean KW - new combination KW - new record KW - taxonomy KW - vascular plants Y1 - 2019 U6 - https://doi.org/10.3372/wi.49.49312 SN - 0511-9618 VL - 49 IS - 3 SP - 421 EP - 445 PB - Botanischer Garten & botanisches Museum Berlin-Dahlem CY - Berlin ER - TY - JOUR A1 - Lauterbach, D. A1 - Roemermann, C. A1 - Jeltsch, Florian A1 - Ristow, Michael T1 - Factors driving plant rarity in dry grasslands on different spatial scales: a functional trait approach JF - BIODIVERSITY AND CONSERVATION N2 - In European dry grasslands land-use changes affect plant species performance and frequency. Potential driving forces are eutrophication and habitat fragmentation. The importance of these factors is presumably scale dependent. We used a functional trait approach to detect processes that influence species frequency and endangerment on different spatial scales. We tested for associations between functional traits and (1) frequency and (2) degree of endangerment on local, regional and national scales. We focussed on five selected traits that describe the life-history of plant species and that are related to competition, dispersal ability and habitat specificity. Trait data on plant height, SLA, plant coverage, peak of flowering and diaspore mass were measured for 28 perennials from common to rare and endangered to non-endangered on 59 dry grassland sites in north-eastern Germany. Multiple regression models revealed that species frequency is positively and species endangerment negatively related to plant height, plant coverage and SLA on more than one spatial scale. On the local scale, diaspore mass has a negative effect on species frequency. More frequent and less endangered species show a later peak of flowering on nationwide and regional scales. We concluded that competition traits are more important on larger scales, whereas dispersal traits are more important for species frequency on the smaller scale. On national and regional scales, eutrophication and habitat loss may be the main drivers of species threat, whereas on the local scale fragmentation plays a crucial role for the performance of dry grassland species. KW - Species frequency KW - Species endangerment KW - Fragmentation KW - Eutrophication KW - SLA Y1 - 2013 U6 - https://doi.org/10.1007/s10531-013-0455-y SN - 0960-3115 VL - 22 IS - 10 SP - 2337 EP - 2352 PB - SPRINGER CY - DORDRECHT ER - TY - JOUR A1 - Ristow, Michael A1 - Panitsa, Maria A1 - Meyer, Stefan A1 - Bergmeier, Erwin T1 - Factors of detection deficits in vascular plant inventories - an island case study JF - Diversity N2 - The degree of completeness of large-scale floristic inventories is often difficult to judge. We compared prior vascular plant species inventories of the Mediterranean island of Limnos (North Aegean, Greece) with 231 recent records from 2016-2021. Together with the recent records, the known number of vascular plant species on the island is 960 native taxa, 63 established neophytes, and 27 species of as yet casual status for a total of 1050 taxa. We looked at a number of traits (plant family, size, flower color, perceptibility, habitat, reproduction period, rarity, and status) to investigate whether they were overrepresented in the dataset of the newly found taxa. Overrepresentation was found in some plant families (e.g., Poaceae and Chenopodiaceae) and for traits such as hydrophytic life form, unobtrusive flower color, coastal as well as agricultural and ruderal habitats, and late (summer/autumn) reproduction period. Apart from the well-known fact of esthetic bias, we found evidence for ecological and perceptibility biases. Plant species inventories based on prior piecemeal collated data should focus on regionally specific species groups and underrepresented and rare habitats. KW - Aegean flora KW - floristic survey KW - Mediterranean island KW - perceptibility KW - habitat KW - plant traits KW - rarity Y1 - 2022 U6 - https://doi.org/10.3390/d14040303 SN - 1424-2818 VL - 14 IS - 4 PB - MDPI CY - Basel ER - TY - JOUR A1 - Bergholz, Kolja A1 - Jeltsch, Florian A1 - Weiß, Lina A1 - Pottek, Janine A1 - Geißler, Katja A1 - Ristow, Michael T1 - Fertilization affects the establishment ability of species differing in seed mass via direct nutrient addition and indirect competition effects JF - Oikos N2 - Fertilization causes species loss and species dominance changes in plant communities worldwide. However, it still remains unclear how fertilization acts upon species functional traits, e.g. seed mass. Seed mass is a key trait of the regeneration strategy of plants, which influences a range of processes during the seedling establishment phase. Fertilization may select upon seed mass, either directly by increased nutrient availability or indirectly by increased competition. Since previous research has mainly analyzed the indirect effects of fertilization, we disentangled the direct and indirect effects to examine how nutrient availability and competition influence the seed mass relationships on four key components during seedling establishment: seedling emergence, time of seedling emergence, seedling survival and seedling growth. We conducted a common garden experiment with 22 dry grassland species with a two-way full factorial design that simulated additional nutrient supply and increased competition. While we found no evidence that fertilization either directly by additional nutrient supply or indirectly by increased competition alters the relationship between seed mass and (time of) seedling emergence, we revealed that large seed mass is beneficial under nutrient-poor conditions (seedlings have greater chances of survival, particularly in nutrient-poor soils) as well as under competition (large-seeded species produced larger seedlings, which suffered less from competition than small-seeded species). Based on these findings, we argue that both factors, i.e. nutrient availability and competition intensity, ought to be considered to understand how fertilization influences seedling establishment and species composition with respect to seed mass in natural communities. We propose a simple conceptual model, in which seed mass in natural communities is determined by competition intensity and nutrient availability. Here, we hypothesize that seed mass shows a U-shaped pattern along gradients of soil fertility, which may explain the contrasting soil fertility-seed mass relationships found in the recent literature. Y1 - 2015 U6 - https://doi.org/10.1111/oik.02193 SN - 0030-1299 SN - 1600-0706 VL - 124 IS - 11 SP - 1547 EP - 1554 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Lauterbach, Dirk A1 - Ristow, Michael A1 - Gemeinholzer, B. T1 - Genetic population structure, fitness variation and the importance of population history in remnant populations of the endangered plant Silene chlorantha (Willd.) Ehrh. (Caryophyllaceae) JF - Plant biology N2 - Habitat fragmentation can lead to a decline of genetic diversity, a potential risk for the survival of natural populations. Fragmented populations can become highly differentiated due to reduced gene flow and genetic drift. A decline in number of individuals can result in lower reproductive fitness due to inbreeding effects. We investigated genetic variation within and between 11 populations of the rare and endangered plant Silene chlorantha in northeastern Germany to support conservation strategies. Genetic diversity was evaluated using AFLP techniques and the results were correlated to fitness traits. Fitness evaluation in nature and in a common garden approach was conducted. Our analysis revealed population differentiation was high and within population genetic diversity was intermediate. A clear population structure was supported by a Bayesian approach, AMOVA and neighbour-joining analysis. No correlation between genetic and geographic distance was found. Our results indicate that patterns of population differentiation were mainly caused by temporal and/or spatial isolation and genetic drift. The fitness evaluation revealed that pollinator limitation and habitat quality seem, at present, to be more important to reproductive fitness than genetic diversity by itself. Populations of S. chlorantha with low genetic diversity have the potential to increase in individual number if habitat conditions improve. This was detected in a single large population in the investigation area, which was formerly affected by bottleneck effects. KW - AFLP KW - fitness KW - population genetic structure KW - population history Y1 - 2011 U6 - https://doi.org/10.1111/j.1438-8677.2010.00418.x SN - 1435-8603 VL - 13 IS - 4 SP - 667 EP - 677 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Berg, Christian A1 - Bilz, Melanie A1 - Ristow, Michael A1 - Raab, Bernd T1 - Important Plant Areas (IPA) : ein internationales Konzept zum Schutz der Wildpflanzen der Erde Y1 - 2008 ER - TY - JOUR A1 - Schulz, Tim Julius A1 - Thierbach, Renè A1 - Voigt, Anja A1 - Drewes, Gunnar A1 - Mietzner, Brun A1 - Steinberg, Pablo A1 - Pfeiffer, Andreas F. H. A1 - Ristow, Michael T1 - Induction of oxidative metabolism by mitochondrial frataxin inhibits cancer growth : Otto Warburg revisited N2 - More than 80 years ago Otto Warburg suggested that cancer might be caused by a decrease in mitochondrial energy metabolism paralleled by an increase in glycolytic flux. In later years, it was shown that cancer cells exhibit multiple alterations in mitochondrial content, structure, function, and activity. We have stably overexpressed the Friedreich ataxia-associated protein frataxin in several colon cancer cell lines. These cells have increased oxidative metabolism, as shown by concurrent increases in aconitase activity, mitochondrial membrane potential, cellular respiration, and ATP content. Consistent with Warburg's hypothesis, we found that frataxin-overexpressing cells also have decreased growth rates and increased population doubling times, show inhibited colony formation capacity in soft agar assays, and exhibit a reduced capacity for tumor formation when injected into nude mice. Furthermore, overexpression of frataxin leads to an increased phosphorylation of the tumor suppressor p38 mitogen-activated protein kinase, as well as decreased phosphorylation of extracellular signal-regulated kinase. Taken together, these results support the view that an increase in oxidative metabolism induced by mitochondrial frataxin may inhibit cancer growth in mammals Y1 - 2006 UR - http://www.jbc.org/content/281/2/977.full.pdf+html U6 - https://doi.org/10.1074/jbc.M511064200 ER - TY - JOUR A1 - Bleeker, Walter A1 - Schmitz, Ulf A1 - Ristow, Michael T1 - Interspecific hybridisation between alien and native plant species in Germany and its consequences for native biodiversity N2 - We explored the extent of interspecific hybridisation between alien and native plant species in Germany with a special focus on the potential threat for native biodiversity. In total we listed 134 hybrids which are interpreted as products of hybridisation between 81 alien and 109 native plant species (including 13 archeophytes) that occur in Germany Seventy-five of these hybrids have been recorded in Germany, while the remaining 59 hybrids have not been detected in Germany yet, although both parental species currently occur in Germany. Interspecific hybridisation between abundant alien and rare native species can threaten populations of the native species through outbreeding depression and/ or through high rates of gene flow swamping native populations. We identified 37 threatened native plant species which hybridise with aliens. Seventeen of these threatened plant species may suffer from outbreeding depression when hybridising with a more abundant alien invader (minority disadvantage). Using hybrid abundance as an indicator of hybrid fitness we argue that introgression of alien genes may affect the gene pool of eight threatened native plant species. Consequently, hybridisation with aliens has to be considered as an additional risk potentially leading to a loss of biodiversity and should be included in the repertoire of causes for rare species extinction in German Red Lists of threatened plant species. Y1 - 2007 UR - http://www.sciencedirect.com/science/journal/00063207 U6 - https://doi.org/10.1016/j.biocon.2007.02.004 SN - 0006-3207 ER - TY - JOUR A1 - Prasse, Rüdiger A1 - Ristow, Michael A1 - Klemm, Gunther A1 - Machatzi, Bernd A1 - Raus, Thomas A1 - Scholz, Hildemar A1 - Stohr, Gerrit A1 - Sukopp, Herbert A1 - Zimmermann, Friedrich T1 - Liste der wildwachsenden Gefäßpflanzen des Landes Berlin : mit Roter Liste Y1 - 2001 SN - 3-88961-137-0 PB - Kulturbuch-Verl. CY - Berlin ER - TY - JOUR A1 - Ristow, Michael A1 - Herrmann, Andreas A1 - Illig, Hubert A1 - Klemm, Gunther A1 - Kummer, Volker A1 - Kläge, Hans-Christian A1 - Machatzi, Bernd A1 - Raetzel, Stefan A1 - Schwarz, R. A1 - Zimmermann, Friedrich T1 - Liste und Rote Liste der etablierten Gefäßpflanzen Brandenburgs Y1 - 2006 ER - TY - JOUR A1 - May, Felix A1 - Giladi, Itamar A1 - Ristow, Michael A1 - Ziv, Yaron A1 - Jeltsch, Florian T1 - Metacommunity, mainland-island system or island communities? : assessing the regional dynamics of plant communities in a fragmented landscape JF - Ecography : pattern and diversity in ecology ; research papers forum N2 - Understanding the regional dynamics of plant communities is crucial for predicting the response of plant diversity to habitat fragmentation. However, for fragmented landscapes the importance of regional processes, such as seed dispersal among isolated habitat patches, has been controversially debated. Due to the stochasticity and rarity of among-patch dispersal and colonization events, we still lack a quantitative understanding of the consequences of these processes at the landscape-scale. In this study, we used extensive field data from a fragmented, semi-arid landscape in Israel to parameterize a multi-species incidence-function model. This model simulates species occupancy pattern based on patch areas and habitat configuration and explicitly considers the locations and the shapes of habitat patches for the derivation of patch connectivity. We implemented an approximate Bayesian computation approach for parameter inference and uncertainty assessment. We tested which of the three types of regional dynamics - the metacommunity, the mainland-island, or the island communities type - best represents the community dynamics in the study area and applied the simulation model to estimate the extinction debt in the investigated landscape. We found that the regional dynamics in the patch-matrix study landscape is best represented as a system of highly isolated island' communities with low rates of propagule exchange among habitat patches and consequently low colonization rates in local communities. Accordingly, the extinction rates in the local communities are the main drivers of community dynamics. Our findings indicate that the landscape carries a significant extinction debt and in model projections 33-60% of all species went extinct within 1000 yr. Our study demonstrates that the combination of dynamic simulation models with field data provides a promising approach for understanding regional community dynamics and for projecting community responses to habitat fragmentation. The approach bears the potential for efficient tests of conservation activities aimed at mitigating future losses of biodiversity. Y1 - 2013 U6 - https://doi.org/10.1111/j.1600-0587.2012.07793.x SN - 0906-7590 VL - 36 IS - 7 SP - 842 EP - 853 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Doyle, U A1 - Vohland, K A1 - Rock, J A1 - Schuemann, K A1 - Ristow, Michael T1 - Nachwachsende Rohstoffe : eine Einschätzung aus Sicht des Naturschutzes Y1 - 2007 ER - TY - JOUR A1 - Groth, Birgit A1 - Seitz, Birgit A1 - Ristow, Michael T1 - Naturschutzfachlich geeignete Baum- und Straucharten für die Verwendung bei Kompensationsmaßnahmen in der freien Landschaft in Brandenburg Y1 - 2003 ER - TY - JOUR A1 - Ristow, Michael A1 - Seitz, Birgit T1 - Neue Fundorte - Bestätigungen - Verluste (299 - 323) Y1 - 2004 SN - 1617-5506 ER - TY - JOUR A1 - Horn, Sebastian A1 - Hempel, Stefan A1 - Ristow, Michael A1 - Rillig, Matthias C. A1 - Kowarik, Ingo A1 - Caruso, Tancredi T1 - Plant community assembly at small scales: Spatial vs. environmental factors in a European grassland JF - Acta oecologica : international journal of ecology N2 - Dispersal limitation and environmental conditions are crucial drivers of plant species distribution and establishment. As these factors operate at different spatial scales, we asked: Do the environmental factors known to determine community assembly at broad scales operate at fine scales (few meters)? How much do these factors account for community variation at fine scales? In which way do biotic and abiotic interactions drive changes in species composition? We surveyed the plant community within a dry grassland along a very steep gradient of soil characteristics like pH and nutrients. We used a spatially explicit sampling design, based on three replicated macroplots of 15 x 15, 12 x 12 and 12 x 12 m in extent. Soil samples were taken to quantify several soil properties (carbon, nitrogen, plant available phosphorus, pH, water content and dehydrogenase activity as a proxy for overall microbial activity). We performed variance partitioning to assess the effect of these variables on plant composition and statistically controlled for spatial autocorrelation via eigenvector mapping. We also applied null model analysis to test for non-random patterns in species co-occurrence using randomization schemes that account for patterns expected under species interactions. At a fine spatial scale, environmental factors explained 18% of variation when controlling for spatial autocorrelation in the distribution of plant species, whereas purely spatial processes accounted for 14% variation. Null model analysis showed that species spatially segregated in a non-random way and these spatial patterns could be due to a combination of environmental filtering and biotic interactions. Our grassland study suggests that environmental factors found to be directly relevant in broad scale studies are present also at small scales, but are supplemented by spatial processes and more direct interactions like competition. (C) 2015 Elsevier Masson SAS. All rights reserved. KW - Assembly pattern KW - Dispersal limitation KW - Festuca brevipila KW - Niche partitioning KW - Null model KW - Plant community ecology KW - Variance partitioning Y1 - 2015 U6 - https://doi.org/10.1016/j.actao.2015.01.004 SN - 1146-609X SN - 1873-6238 VL - 63 SP - 56 EP - 62 PB - Elsevier CY - Paris ER - TY - JOUR A1 - May, Felix A1 - Giladi, Itamar A1 - Ristow, Michael A1 - Ziv, Yaron A1 - Jeltsch, Florian T1 - Plant functional traits and community assembly along interacting gradients of productivity and fragmentation JF - Perspectives in plant ecology, evolution and systematics N2 - Quantifying the association of plant functional traits to environmental gradients is a promising approach for understanding and projecting community responses to land use and climatic changes. Although habitat fragmentation and climate are expected to affect plant communities interactively, there is a lack of empirical studies addressing trait associations to fragmentation in different climatic regimes. In this study, we analyse data on the key functional traits: specific leaf area (SLA), plant height, seed mass and seed number. First, we assess the evidence for the community assembly mechanisms habitat filtering and competition at different spatial scales, using several null-models and a comprehensive set of community-level trait convergence and divergence indices. Second, we analyse the association of community-mean traits with patch area and connectivity along a south-north productivity gradient. We found clear evidence for trait convergence due to habitat filtering. In contrast, the evidence for trait divergence due to competition fundamentally depended on the null-model used. When the null-model controlled for habitat filtering, there was only evidence for trait divergence at the smallest sampling scale (0.25 m x 0.25 m). All traits varied significantly along the S-N productivity gradient. While plant height and SLA were consistently associated with fragmentation, the association of seed mass and seed number with fragmentation changed along the S-N gradient. Our findings indicate trait convergence due to drought stress in the arid sites and due to higher productivity in the mesic sites. The association of plant traits to fragmentation is likely driven by increased colonization ability in small and/or isolated patches (plant height, seed number) or increased persistence ability in isolated patches (seed mass). Our study provides the first empirical test of trait associations with fragmentation along a productivity gradient. We conclude that it is crucial to study the interactive effects of different ecological drivers on plant functional traits. KW - Connectivity KW - Drought-stress KW - Habitat filtering KW - Limiting similarity KW - Null models KW - Plant height KW - Seed mass KW - Seed number KW - Specific leaf area (SLA) Y1 - 2013 U6 - https://doi.org/10.1016/j.ppees.2013.08.002 SN - 1433-8319 VL - 15 IS - 6 SP - 304 EP - 318 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Bergholz, Kolja A1 - Sittel, Lara-Pauline A1 - Ristow, Michael A1 - Jeltsch, Florian A1 - Weiss, Lina T1 - Pollinator guilds respond contrastingly at different scales to landscape parameters of land-use intensity JF - Ecology and evolution N2 - Land-use intensification is the main factor for the catastrophic decline of insect pollinators. However, land-use intensification includes multiple processes that act across various scales and should affect pollinator guilds differently depending on their ecology. We aimed to reveal how two main pollinator guilds, wild bees and hoverflies, respond to different land-use intensification measures, that is, arable field cover (AFC), landscape heterogeneity (LH), and functional flower composition of local plant communities as a measure of habitat quality. We sampled wild bees and hoverflies on 22 dry grassland sites within a highly intensified landscape (NE Germany) within three campaigns using pan traps. We estimated AFC and LH on consecutive radii (60-3000 m) around the dry grassland sites and estimated the local functional flower composition. Wild bee species richness and abundance was positively affected by LH and negatively by AFC at small scales (140-400 m). In contrast, hoverflies were positively affected by AFC and negatively by LH at larger scales (500-3000 m), where both landscape parameters were negatively correlated to each other. At small spatial scales, though, LH had a positive effect on hoverfly abundance. Functional flower diversity had no positive effect on pollinators, but conspicuous flowers seem to attract abundance of hoverflies. In conclusion, landscape parameters contrarily affect two pollinator guilds at different scales. The correlation of landscape parameters may influence the observed relationships between landscape parameters and pollinators. Hence, effects of land-use intensification seem to be highly landscape-specific. KW - hoverflies KW - landscape homogenization KW - plant functional trait KW - syrphids KW - wild bees Y1 - 2022 U6 - https://doi.org/10.1002/ece3.8708 SN - 2045-7758 VL - 12 IS - 3 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Bergholz, Kolja A1 - Sittel, Lara-Pauline A1 - Ristow, Michael A1 - Jeltsch, Florian A1 - Weiß, Lina T1 - Pollinator guilds respond contrastingly at different scales to landscape parameters of land-use intensity JF - Ecology and Evolution N2 - Land-use intensification is the main factor for the catastrophic decline of insect pollinators. However, land-use intensification includes multiple processes that act across various scales and should affect pollinator guilds differently depending on their ecology. We aimed to reveal how two main pollinator guilds, wild bees and hoverflies, respond to different land-use intensification measures, that is, arable field cover (AFC), landscape heterogeneity (LH), and functional flower composition of local plant communities as a measure of habitat quality. We sampled wild bees and hoverflies on 22 dry grassland sites within a highly intensified landscape (NE Germany) within three campaigns using pan traps. We estimated AFC and LH on consecutive radii (60–3000 m) around the dry grassland sites and estimated the local functional flower composition. Wild bee species richness and abundance was positively affected by LH and negatively by AFC at small scales (140–400 m). In contrast, hoverflies were positively affected by AFC and negatively by LH at larger scales (500–3000 m), where both landscape parameters were negatively correlated to each other. At small spatial scales, though, LH had a positive effect on hoverfly abundance. Functional flower diversity had no positive effect on pollinators, but conspicuous flowers seem to attract abundance of hoverflies. In conclusion, landscape parameters contrarily affect two pollinator guilds at different scales. The correlation of landscape parameters may influence the observed relationships between landscape parameters and pollinators. Hence, effects of land-use intensification seem to be highly landscape-specific. KW - hoverflies KW - landscape homogenization KW - plant functional trait KW - syrphids KW - wild bees Y1 - 2022 U6 - https://doi.org/10.1002/ece3.8708 SN - 2045-7758 VL - 12 IS - 3 PB - John Wiley & Sons, Inc. CY - Hoboken (New Jersey) ER - TY - JOUR A1 - Lauterbach, Daniel A1 - Ristow, Michael A1 - Gemeinholzer, Birgit T1 - Population genetics and fitness in fragmented populations of the dioecious and endangered Silene otites (Caryophyllaceae) JF - Plant systematics and evolution N2 - Population fragmentation is often correlated with loss of genetic diversity and reduced fitness. Obligate out-crossing (dioecy) is expected to enhance genetic diversity, reduce genetic differentiation, and avoid inbreeding depression through frequent gene flow. However, in highly fragmented populations dioecy has only diminishing effects upon genetic structure as pollination limitations (e.g. flight distance of pollinators) most often restrict inter-population gene flow in insect pollinated species. In fragmented dry grasslands in northeastern Germany, we analysed genetic structure, fitness, and habitat quality of the endangered dioecious Silene otites (Caryophyllaceae). Using AFLP markers, a high level of differentiation among ten populations was found (F (st) = 0.36), while the intra-population genetic diversities (H (E) = 0.165-0.240) were similar as compared to hermaphroditic species. There was neither a correlation between geographic and genetic distance nor between genetic diversity and population size, which indicates reduced gene flow among populations and random genetic drift. Plant size was positively correlated with genetic diversity. Seed set and number of juveniles were positively related to population size. Higher total coverage resulted in reduced plant fitness, and the number of juveniles was negatively correlated to cryptogam cover. Additionally, we found a sex ratio bias towards more male plants in larger populations. Overall, our results indicate that on a regional geographic scale dioecy does not necessarily prevent genetic erosion in the case of habitat fragmentation, especially in the absence of long distance seed and pollen dispersal capacity. KW - AFLP KW - Population size KW - Mating system KW - Isolation by distance KW - Sex ratio Y1 - 2012 U6 - https://doi.org/10.1007/s00606-011-0533-0 SN - 0378-2697 VL - 298 IS - 1 SP - 155 EP - 164 PB - Springer CY - Wien ER - TY - JOUR A1 - Wagner, Viktoria A1 - Antunes, Pedro M. A1 - Ristow, Michael A1 - Lechner, Ute A1 - Hensen, Isabell T1 - Prevailing negative soil biota effect and no evidence for local adaptation in a widespread eurasian grass JF - PLoS one N2 - Background: Soil biota effects are increasingly accepted as an important driver of the abundance and distribution of plants. While biogeographical studies on alien invasive plant species have indicated coevolution with soil biota in their native distribution range, it is unknown whether adaptation to soil biota varies among populations within the native distribution range. The question of local adaptation between plants and their soil biota has important implications for conservation of biodiversity and may justify the use of seed material from local provenances in restoration campaigns. Methodology/Principal Findings: We studied soil biota effects in ten populations of the steppe grass Stipa capillata from two distinct regions, Europe and Asia. We tested for local adaptation at two different scales, both within (ca. 10-80 km) and between (ca. 3300 km) regions, using a reciprocal inoculation experiment in the greenhouse for nine months. Generally, negative soil biota effects were consistent. However, we did not find evidence for local adaptation: both within and between regions, growth of plants in their 'home soil' was not significantly larger relative to that in soil from other, more distant, populations. Conclusions/Significance: Our study suggests that negative soil biota effects can prevail in different parts of a plant species' range. Absence of local adaptation points to the possibility of similar rhizosphere biota composition across populations and regions, sufficient gene flow to prevent coevolution, selection in favor of plasticity, or functional redundancy among different soil biota. From the point of view of plant - soil biota interactions, our findings indicate that the current practice of using seeds exclusively from local provenances in ecosystem restoration campaigns may not be justified. Y1 - 2011 U6 - https://doi.org/10.1371/journal.pone.0017580 SN - 1932-6203 VL - 6 IS - 3 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Machatzi, Bernd A1 - Ratsch, Andreas A1 - Prasse, Rüdiger A1 - Ristow, Michael T1 - Rote Liste und Gesamtartenliste der Heuschrecken und Grillen (Saltatoria: Ensifera et Caelifera) von Berlin N2 - This Red List of grasshoppers and crickets for Berlin is the first that treats the whole area of Berlin, since the two preceding lists focused only on the western parts of the formerly divided city. Until now 54 species of grasshoppers and crickets have been recorded in the area. 46 species have been found to be well established in the wild, while eight species were only non breeding accidental immigrants or species whose successful reproduction has only been observed in greenhouses or similar structures. Of the 46 species being well established in the past and/or present 22 must be included in one of the threat categories, indicating that the populations of these species are already endangered. Additionally, seven species belong to the category "Near Threatened". Only 17 of the grasshopper and cricket species of Berlin are not threatened. Y1 - 2005 SN - 3-00016815-x ER - TY - JOUR A1 - Düvel, Martina A1 - Ristow, Michael A1 - Scholz, Hildemar T1 - Scolochloa marchica sp. nova : ein neues Röhrichtgras aus Mitteleuropa Y1 - 2001 SN - 0014-8962 ER - TY - JOUR A1 - Thierbach, Rene A1 - Florian, Simone A1 - Wolfrum, Katharina A1 - Voigt, Anja A1 - Drewes, Gunnar A1 - Blume, Urte A1 - Bannasch, Peter A1 - Ristow, Michael A1 - Steinberg, Pablo T1 - Specific alterations of carbohydrate metabolism are associated with hepatocarcinogenesis in mitochondrially impaired mice JF - Human molecular genetics N2 - Friedreich's ataxia is an inherited neurodegenerative disease caused by the reduced expression of the mitochondrially active protein frataxin. We have previously shown that mice with a hepatocyte-specific frataxin knockout (AlbFxn(-/-)) develop multiple hepatic tumors in later life. In the present study, hepatic carbohydrate metabolism in AlbFxn(-/-) mice at an early and late life stage was analyzed. In young (5-week-old) AlbFxn(-/-) mice hepatic ATP, glucose-6-phosphate and glycogen levels were found to be reduced by similar to 74, 80 and 88%, respectively, when compared with control animals. This pronounced ATP, G6P and glycogen depletion in the livers of young mice reverted in older animals: while half of the mice die before 30 weeks of age, the other half reaches 17 months of age and exhibits glycogen, G6P and ATP levels similar to those in age-matched controls. A key event in this respect seems to be the up-regulation of GLUT1, the predominant glucose transporter in fetal liver parenchyma, which became evident in AlbFxn(-/-) mice being 5-12 weeks of age. The most significant histological findings in animals being 17 or 22 months of age were the appearance of multiple clear cell, mixed cell and basophilic foci throughout the liver parenchyma as well as the development of hepatocellular adenomas and carcinomas. The hepatocarcinogenic process in AlbFxn 2/2 mice shows remarkable differences regarding carbohydrate metabolism alterations when compared with all other chemically and virally driven liver cancer models described up to now. Y1 - 2012 U6 - https://doi.org/10.1093/hmg/ddr499 SN - 0964-6906 VL - 21 IS - 3 SP - 656 EP - 663 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Gemeinholzer, B. A1 - May, F. A1 - Ristow, Michael A1 - Batsch, C. A1 - Lauterbach, D. T1 - Strong genetic differentiation on a fragmentation gradient among populations of the heterocarpic annual Catananche lutea L. (Asteraceae) JF - Plant systematics and evolution N2 - In landscapes which are predominately characterised by agriculture, natural ecosystems are often reduced to a mosaic of scattered patches of natural vegetation. Species with formerly connected distribution ranges now have restricted gene flow among populations. This has isolating effects upon population structure, because species are often confined by their limited dispersal capabilities. In this study, we test the effects of habitat fragmentation, precipitation, and isolation of populations on the genetic structure (AFLP) and fitness of the Asteraceae Catananche lutea. Our study area is an agro-dominated ecosystem in the desert-Mediterranean transition zone of the Southern Judea Lowlands in Israel. Our analysis revealed an intermediate level of intra-population genetic diversity across the study site with reduced genetic diversity on smaller scale. Although the size of the whole study area was relatively small (20 x 45 km), we found isolation by distance to be effective. We detected a high level of genetic differentiation among populations but genetic structure did not reflect spatial patterns. Population genetic diversity was correlated neither with position along the precipitation gradient nor with different seed types or other plant fitness variables in C. lutea. KW - AFLP KW - Heterocarpy KW - Population structure KW - Precipitation gradient KW - Asteraceae Y1 - 2012 U6 - https://doi.org/10.1007/s00606-012-0661-1 SN - 0378-2697 VL - 298 IS - 8 SP - 1585 EP - 1596 PB - Springer CY - Wien ER - TY - JOUR A1 - Uhlemann, Ingo A1 - Hahn, Steffen A1 - Ristow, Michael A1 - Sackwitz, Peter T1 - Taraxacum Sectio Naevosa M. P. Christiansen (Taraxacum spectabile auct. germ. p. p.) in Deutschland Y1 - 2002 ER - TY - JOUR A1 - Thierbach, Rene A1 - Schulz, Tim Julius A1 - Voigt, Aanja A1 - Drewes, Gunnar A1 - Isken, F. A1 - Pfeiffer, Andreas F. H. A1 - Ristow, Michael A1 - Steinberg, Pablo T1 - Targeted disruption of frataxin in hepatocytes causes spontaneous neoplasia accompanied by increased ROS formation Y1 - 2004 SN - 0028-1298 ER - TY - JOUR A1 - Thierbach, Renè A1 - Schulz, Tim Julius A1 - Isken, Frank A1 - Voigt, Aanja A1 - Mietzner, Brun A1 - Drewes, Gunnar A1 - von Kleist-Retzow, Jürgen-Christoph A1 - Wiesner, Rudolf J. A1 - Magnuson, Mark A. A1 - Puccio, Helene A1 - Pfeiffer, Andreas F. H. A1 - Steinberg, Pablo A1 - Ristow, Michael T1 - Targeted disruption of hepatic frataxin expression causes impaired mitochondrial function, decreased life span and tumor growth in mice N2 - We have disrupted expression of the mitochondrial Friedreich ataxia protein frataxin specifically in murine hepatocytes to generate mice with impaired mitochondrial function and decreased oxidative phosphorylation. These animals have a reduced life span and develop multiple hepatic tumors. Livers also show increased oxidative stress, impaired respiration and reduced ATP levels paralleled by reduced activity of iron-sulfur cluster (Fe/S) containing proteins (ISP), which all leads to increased hepatocyte turnover by promoting both apoptosis and proliferation. Accordingly, phosphorylation of the stress-inducible p38 MAP kinase was found to be specifically impaired following disruption of frataxin. Taken together, these findings indicate that frataxin may act as a mitochondrial tumor suppressor protein in mammals Y1 - 2005 ER - TY - JOUR A1 - Thierbach, René A1 - Drewes, Gunnar A1 - Fusser, Markus A1 - Voigt, Anja A1 - Kuhlow, Doreen A1 - Blume, Urte A1 - Schulz, Tim Julius A1 - Reiche, Carina A1 - Glatt, Hansruedi A1 - Epe, Bernd A1 - Steinberg, Pablo A1 - Ristow, Michael T1 - The Friedreich's ataxia protein frataxin modulates DNA base excision repair in prokaryotes and mammals N2 - DNA-repair mechanisms enable cells to maintain their genetic information by protecting it from mutations that may cause malignant growth. Recent evidence suggests that specific DNA-repair enzymes contain ISCs (iron-sulfur clusters). The nuclear-encoded protein frataxin is essential for the mitochondrial biosynthesis of ISCs. Frataxin deficiency causes a neurodegenerative disorder named Friedreich's ataxia in humans. Various types of cancer occurring at young age are associated with this disease, and hence with frataxin deficiency. Mice carrying a hepatocyte- specific disruption of the frataxin gene develop multiple liver tumours for unresolved reasons. In the present study, we show that frataxin deficiency in murine liver is associated with increased basal levels of oxidative DNA base damage. Accordingly, eukaryotic V79 fibroblasts overexpressing human frataxin show decreased basal levels of these modifications, while prokaryotic Salmonella enterica serotype Typhimurium TA 104 strains transformed with human frataxin show decreased mutation rates. The repair rates of oxidative DNA base modifications in V79 cells overexpressing frataxin were significantly higher than in control cells. Lastly, cleavage activity related to the ISC-independent repair enzyme 8-oxoguanine glycosylase was found to be unaltered by frataxin overexpression. These findings indicate that frataxin modulates DNA-repair mechanisms probably due to its impact on ISC-dependent repair proteins, linking mitochondrial dysfunction to DNA repair and tumour initiation. Y1 - 2010 UR - http://www.biochemj.org/bj/toc.htm U6 - https://doi.org/10.1042/Bj20101116 SN - 0264-6021 ER - TY - JOUR A1 - Bergholz, Kolja A1 - May, Felix A1 - Ristow, Michael A1 - Giladi, Itamar A1 - Ziv, Yaron A1 - Jeltsch, Florian T1 - Two Mediterranean annuals feature high within-population trait variability and respond differently to a precipitation gradient JF - Basic and applied ecology : Journal of the Gesellschaft für Ökologie N2 - Intraspecific trait variability plays an important role in species adaptation to climate change. However, it still remains unclear how plants in semi-arid environments respond to increasing aridity. We investigated the intraspecific trait variability of two common Mediterranean annuals (Geropogon hybridus and Crupina crupinastrum) with similar habitat preferences. They were studied along a steep precipitation gradient in Israel similar to the maximum predicted precipitation changes in the eastern Mediterranean basin (i.e. -30% until 2100). We expected a shift from competitive ability to stress tolerance with decreasing precipitation and tested this expectation by measuring key functional traits (canopy and seed release height, specific leaf area, N-and P-leaf content, seed mass). Further, we evaluated generative bet-hedging strategies by different seed traits. Both species showed different responses along the precipitation gradient. C. crupinastrum exhibited only decreased plant height toward saridity, while G. hybridus showed strong trends of generative adaptation to aridity. Different seed trait indices suggest increased bet-hedging of G. hybridus in arid environments. However, no clear trends along the precipitation gradient were observed in leaf traits (specific leaf area and leaf N-/P-content) in both species. Moreover, variance decomposition revealed that most of the observed trait variation (>> 50%) is found within populations. The findings of our study suggest that responses to increased aridity are highly species-specific and local environmental factors may have a stronger effect on intraspecific trait variation than shifts in annual precipitation. We therefore argue that trait-based analyses should focus on precipitation gradients that are comparable to predicted precipitation changes and compare precipitation effects to effects of local environmental factors. (C) 2017 Gesellschaft fur Okologie. Published by Elsevier GmbH. All rights reserved. KW - Climate change KW - Functional ecology KW - Plant height KW - Drought stress KW - Rainfall gradient KW - Trait-environment relationship KW - Local adaptation KW - Phenotypic plasticity Y1 - 2017 U6 - https://doi.org/10.1016/j.baae.2017.11.001 SN - 1439-1791 SN - 1618-0089 VL - 25 SP - 48 EP - 58 PB - Elsevier CY - Jena ER - TY - JOUR A1 - Ristow, Michael A1 - Burkart, Michael A1 - Prasse, Rüdiger T1 - Zum Vorkommen der Bleichen Hainsimse, Luzula pallidula Kirschner (syn. L. pallescens auct.) in Brandenburg Y1 - 1997 ER - TY - JOUR A1 - Ristow, Michael A1 - Seitz, Birgit T1 - Zur Kenntnis einiger übersehener, wenig beachteter oder verkannter Sippen der Gattungen Vicia und Valerianella in Brandenburg Y1 - 2002 ER - TY - JOUR A1 - Seitz, Birgit A1 - Ristow, Michael A1 - Klemm, Gunther A1 - Rätzel, Stefan A1 - Schulze, Gerhart A1 - Hoffmann, Maik T1 - Zur Verbreitung der Wildrosen und verwilderten Kulturrosen in Berlin und Brandenburg Y1 - 2004 SN - 0724-3111 - ER -