Items 1-20 of 597

    • Journal Article

      Mapping Cellular Microenvironments: Proximity Labeling and Complexome Profiling (Seventh Symposium of the Göttingen Proteomics Forum) 

      Valerius, Oliver; Asif, Abdul R.; Beißbarth, Tim; Bohrer, Rainer; Dihazi, Hassan; Feussner, Kirstin; Jahn, Olaf; Majcherczyk, Andrzej; Schmidt, Bernhard; Schmitt, Kerstin; et al.
      Urlaub, HenningLenz, Christof
      Cells 2019; 8(10): Art. 1192
      Mass spectrometry-based proteomics methods are finding increasing use in structural biology research. Beyond simple interaction networks, information about stable protein-protein complexes or spatially proximal proteins helps to elucidate the biological functions of proteins in a wider cellular context. To shed light on new developments in this field, the Göttingen Proteomics Forum organized a one-day symposium focused on complexome profiling and proximity labeling, two emerging technologies that are gaining significant attention in biomolecular research. The symposium was held in Göttingen, Germany on 23 May, 2019, as part of a series of regular symposia organized by the Göttingen Proteomics Forum.
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    • Journal Article

      Antifreezing Hydrogel with High Zinc Reversibility for Flexible and Durable Aqueous Batteries by Cooperative Hydrated Cations 

      Zhu, Minshen; Wang, Xiaojie; Tang, Hongmei; Wang, Jiawei; Hao, Qi; Liu, Lixiang; Li, Yang; Zhang, Kai; Schmidt, Oliver G.
      Advanced Functional Materials: Art. 1907218
      Hydrogels are widely used in flexible aqueous batteries due to their liquid-like ion transportation abilities and solid-like mechanical properties. Their potential applications in flexible and wearable electronics introduce a fundamental challenge: how to lower the freezing point of hydrogels to preserve these merits without sacrificing hydrogels’ basic advantages in low cost and high safety. Moreover, zinc as an ideal anode in aqueous batteries suffers from low reversibility because of the formation of insulative byproducts, which is mainly caused by hydrogen evolution via extensive hydration of zinc ions. This, in principle, requires the suppression of hydration, which induces an undesirable increase in the freezing point of hydrogels. Here, it is demonstrated that cooperatively hydrated cations, zinc and lithium ions in hydrogels, are very effective in addressing the above challenges. This simple but unique hydrogel not only enables a 98% capacity retention upon cooling down to −20 °C from room temperature but also allows a near 100% capacity retention with >99.5% Coulombic efficiency over 500 cycles at −20 °C. In addition, the strengthened mechanical properties of the hydrogel under subzero temperatures result in excellent durability under various harsh deformations after the freezing process.
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    • Journal Article

      Comparison of three dielectric barrier discharges regarding their physical characteristics and influence on the adhesion properties on maple, high density fiberboards and wood plastic composite 

      Peters, F.; Hünnekens, B.; Wieneke, S.; Militz, H.; Ohms, G.; Viöl, W.
      Journal of Physics D: Applied Physics 2017; 50(47)
      In this study, three different dielectric barrier discharges, based on the same setup and run with the same power supply, are characterized by emission spectroscopy with regards to the reduced electrical field strength, and the rotational, vibrational and electron temperature. To compare discharges common for the treatment on wood, a coplanar surface barrier discharge, a direct dielectric barrier discharge and a jet system/remote plasma are chosen. To minimize influences due to the setups or power, the discharges are realized with the same electrodes and power supply and normalized to the same power. To evaluate the efficiency of the different discharges and the influence on treated materials, the surface free energy is determined on a maple wood, high density fiberboard and wood plastic composite. The influence is measured depending on the treatment time, with the highest impact in the time of 5 s.
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    • Journal Article

      Scaling Relationships between Leaf Shape and Area of 12 Rosaceae Species 

      Yu, Xiaojing; Hui, Cang; Sandhu, Hardev S.; Lin, Zhiyi; Shi, Peijian
      Symmetry 2019; 11(10)
      Leaf surface area (A) and leaf shape have been demonstrated to be closely correlated with photosynthetic rates. The scaling relationship between leaf biomass (both dry weight and fresh weight) and A has been widely studied. However, few studies have focused on the scaling relationship between leaf shape and A. Here, using more than 3600 leaves from 12 Rosaceae species, we examined the relationships of the leaf-shape indices including the left to right side leaf surface area ratio (AR), the ratio of leaf perimeter to leaf surface area (RPA), and the ratio of leaf width to length (RWL) versus A. We also tested whether there is a scaling relationship between leaf dry weight and A, and between PRA and A. There was no significant correlation between AR and A for each of the 12 species. Leaf area was also found to be independent of RWL because leaf width remained proportional to leaf length across the 12 species. However, there was a negative correlation between RPA and A. The scaling relationship between RPA and A held for each species, and the estimated scaling exponent of RPA versus A approached −1/2; the scaling relationship between leaf dry weight and A also held for each species, and 11 out of the 12 estimated scaling exponents of leaf dry weight versus A were greater than unity. Our results indicated that leaf surface area has a strong scaling relationship with leaf perimeter and also with leaf dry weight but has no relationship with leaf symmetry or RWL. Additionally, our results showed that leaf dry weight per unit area, which is usually associated with the photosynthetic capacity of plants, increases with an increasing A because the scaling exponent of leaf dry weight versus A is greater than unity. This suggests that a large leaf surface area requires more dry mass input to support the physical structure of the leaf.
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    • Journal Article

      Contrasting Global Patterns of Spatially Periodic Fairy Circles and Regular Insect Nests in Drylands 

      Getzin, Stephan; Yizhaq, Hezi; Cramer, Michael D.; Tschinkel, Walter R.
      Journal of Geophysical Research: Biogeosciences
      Numerical analysis of spatial pattern is widely used in ecology to describe the characteristics of floral and faunal distributions. These methods allow attribution of pattern to causal mechanisms by uncovering the specific signatures of patterns and causal agents. For example, grassland‐gap patterns called fairy circles (FCs) in Namibia and Australia are characterized by highly regular and homogenous distributions across landscapes that show spatially periodic ordering. These FCs have been suggested to be caused by both social insects and competitive plant interactions. We compared eight Namibian and Australian FC patterns and also modeled FCs to 16 patterns of social insect nests in Africa, Australia, and America that include the most regular termite mound patterns known. For pattern‐process inference, we used spatial statistics based on both nearest‐neighbor analysis and neighborhood‐density functions. None of the analyzed insect‐nest distributions attain the spatially periodic ordering that is typical of FCs. The inherently more variable patterns of termite and ant nests are commonly attributable to well documented aspects of the faunal life‐history. Our quantitative evidence from drylands shows that the more variable insect‐nest distributions in water‐limited environments cannot explain the characteristic spatial signature of FCs. The analysis demonstrates the interpretation of scale‐dependent neighborhood‐density functions and that it is the identification of unique spatial signatures in regular patterns that need to be linked to process. While our results cannot verify a specific hypothesis, they support the hypothesis that FCs in these drylands are more likely an emergent vegetation pattern caused by strong plant competition for water.
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    • Journal Article

      Episodic fluid flow in an active fault 

      Louis, Sarah; Luijendijk, Elco; Dunkl, István; Person, Mark
      Geology 2019; 47(10) p.938-942
      We present a reconstruction of episodic fluid flow over the past ∼250 k.y. along the Malpais normal fault, which hosts the Beowawe hydrothermal system (Nevada, USA), using a novel combination of the apatite (U-Th)/He (AHe) thermochronometer and a model of the thermal effects of fluid flow. Samples show partial resetting of the AHe thermochronometer in a 40-m-wide zone around the fault. Numerical models using current fluid temperatures and discharge rates indicate that fluid flow events lasting 2 k.y. or more lead to fully reset samples. Episodic fluid pulses lasting 1 k.y. result in partially reset samples, with 30–40 individual fluid pulses required to match the data. Episodic fluid flow is also supported by an overturned geothermal gradient in a borehole that crosses the fault, and by breaks in stable isotope trends in hydrothermal sinter deposits that coincide with two independently dated earthquakes in the past 20 k.y. This suggests a system where fluid flow is triggered by repeated seismic activity, and that seals itself over ∼1 k.y. due to the formation of clays and silicates in the fault damage zone. Hydrothermal activity is younger than the 6–10 Ma age of the fault, which means that deep (∼5 km) fluid flow was initiated only after a large part of the 230 m of fault offset had taken place.
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    • Journal Article

      Multiple components of plant diversity loss determine herbivore phylogenetic diversity in a subtropical forest experiment 

      Wang, Ming‐Qiang; Li, Yi; Chesters, Douglas; Anttonen, Perttu; Bruelheide, Helge; Chen, Jing‐Ting; Durka, Walter; Guo, Peng‐Fei; Härdtle, Werner; Ma, Keping; et al.
      Michalski, Stefan G.Schmid, BernhardOheimb, GoddertWu, Chun‐ShengZhang, Nai‐LiZhou, Qing‐SongSchuldt, AndreasZhu, Chao‐Dong
      Journal of Ecology 2019; 107(6) p.2697-2712
      Plant diversity loss can alter higher trophic -level communities via non -random species interactions, which in turn may cascade to affect key ecosystem func-tions. These non -random linkages might be best captured by patterns of phyloge-netic diversity, which take into account co -evolutionary dependencies. However,lack of adequate phylogenetic data of higher trophic levels hampers our mecha-nistic understanding of biodiversity relationships in species-rich ecosystems.2. We used DNA barcoding to generate data on the phylogenetic diversity of lepi-dopteran caterpillars in a large- scale forest biodiversity experiment in subtropicalChina. We analysed how different metrics of lepidopteran phylogenetic diversity(Faith's PD, MPD, MNTD) and taxonomic diversity were influenced by multiple components of tree diversity (taxonomic, functional, phylogenetic).3. Our data from six sampling periods represent 7,204 mitochondrial cytochrome c oxidase subunit I (COI) sequences of lepidopteran larvae, clustered into 461 mo-lecular operational taxonomic units. Lepidopteran abundance, the effective num-ber of species (irrespective of the focus on rare or common species) and Faith's PD and MPD (reflecting basal evolutionary splits), but not MNTD (reflecting re-cent evolutionary splits), significantly increased with experimentally manipulated ree species richness. Lepidopteran MNTD decreased with increasing tree MNTD. Path analyses showed that tree phylogenetic and functional diversity explained part, but not all of the effects of tree species richness on lepidopteran diversity. Importantly, tree diversity effects on lepidopteran diversity were to a large extent indirect, operating via changes in lepidopteran abundance. 4. Synthesis. Our study shows that evolutionary dependencies determine the response of herbivore communities to changes in host plant diversity. Incorporating a wider range of diversity metrics both at the level of producers and consumers can thus help to develop a more comprehensive understanding of the functional consequences of biodiversity change across trophic levels. Moreover, the dependence of trophic linkages on herbivore abundances underlines the need to address the consequences of current declines in insect abundances for ecosystem structure and functioning.
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    • Journal Article

      Rapid plant colonization of the forelands of a vanishing glacier is strongly associated with species traits 

      Franzén, Markus; Dieker, Petra; Schrader, Julian; Helm, Aveliina
      Arctic, Antarctic, and Alpine Research 2019; 51(1) p.366-378
      Recently developed glacier forelands provide valuable insights into vegetation dynamics. We studied the vascular plants in the glacier forelands of the Ålmajallojekna glacier in comparison to the plants in the surrounding area. The glacier is retreating rapidly at an average rate of 0.17 km2 per year from 1898 to 2012. In the newly emerged glacier forelands, we found that 32 percent of the 381 plant taxa occurred in the surrounding region. Sixty-eight plant species were present on the youngest terrain (0–31 y), an additional thirteen species occurred on terrain aged 32–53 years, and an additional forty-two species were detected on terrain aged 54–114 years. Of the surrounding species pool, plant species that had successfully established in recently deglaciated terrains were characterized by high regional abundance and low seed weight, and they were more likely to be members of the plant families Saxifragaceae, Salicaceae, and Asteraceae. Woody plant species with a preference for well-drained soils were more likely to be present in the youngest terrain. Our results show that the vegetation of glacier forelands is developing rapidly depending on the plant species in the surrounding area and the species’ life-history traits.
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    • Journal Article

      Climatologies at high resolution for the earth’s land surface areas 

      Karger, Dirk Nikolaus; Conrad, Olaf; Böhner, Jürgen; Kawohl, Tobias; Kreft, Holger; Soria-Auza, Rodrigo Wilber; Zimmermann, Niklaus E.; Linder, H. Peter; Kessler, Michael
      Scientific Data 2017; 4(1)
      High-resolution information on climatic conditions is essential to many applications in environmental and ecological sciences. Here we present the CHELSA (Climatologies at high resolution for the earth's land surface areas) data of downscaled model output temperature and precipitation estimates of the ERA-Interim climatic reanalysis to a high resolution of 30 arc sec. The temperature algorithm is based on statistical downscaling of atmospheric temperatures. The precipitation algorithm incorporates orographic predictors including wind fields, valley exposition, and boundary layer height, with a subsequent bias correction. The resulting data consist of a monthly temperature and precipitation climatology for the years 1979-2013. We compare the data derived from the CHELSA algorithm with other standard gridded products and station data from the Global Historical Climate Network. We compare the performance of the new climatologies in species distribution modelling and show that we can increase the accuracy of species range predictions. We further show that CHELSA climatological data has a similar accuracy as other products for temperature, but that its predictions of precipitation patterns are better.
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    • Journal Article

      Effect of Phosphinothricin on Transgenic Downy Birch (Betula pubescens Ehrh.) Containing bar or GS1 Genes 

      Lebedev; Krutovsky; Shestibratov
      Forests 2019; 10(12): Art. 1067
      Weeds are a big problem in agriculture and forestry, and herbicides are the main tools to control them. Phosphinotricin (ammonium glufosinate, PPT) is one of the most effective non-selective herbicides, to which weeds hardly gain resistance, but the reasons for its effect and toxicity to plants are still unclear, and especially, it is little studied in trees, including transgenic ones. We studied the physiological responses of downy birch (Betula pubescens Ehrh.) containing the herbicide resistance bar gene or the cytosol glutamine synthetase GS1 gene (the target enzyme of the herbicide) to PPT-based Basta herbicide treatment in various doses under open-air conditions during two years. Birch saplings with the bar gene were resistant to a double field dose (10 L/ha), but the expression of the GS1 gene only slightly increased resistance compared to the control. Herbicide treatment increased the ammonium level in leaf tissue by 3–8 times, but this, apparently, was not the main cause of plant death. Among leaf pigments, chlorophyll B was the most resistant to PPT, and carotenoids were the most sensitive. Responses of birch trees with the GS1 gene (accumulation of ammonium, pigment content, and dehydration) during treatment with a low dose of herbicide were less pronounced than in control plants. One-year-old control and transgenic plants with the GS gene died after 2.5 L/ha treatment, and two-year-old plants lost foliage after such treatment but remained alive and developed buds four weeks after treatment. Herbicide treatment of plants with the bar gene did not cause significant deviations in height (first year) or the accumulation of aboveground biomass (second year). The obtained results improve our understanding of the effect of PPT on woody plants and can be used both to clarify mechanisms of herbicide action and in plantation forestry.
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    • Journal Article

      Bamboo Water Transport Assessed with Deuterium Tracing 

      Mei, Tingting; Fang, Dongming; Röll, Alexander; Hölscher, Dirk
      Forests 2019; 10(8): Art. 623
      Bamboo water transport comprises the pathway rhizomes-culms-leaves as well as transfer among culms via connected rhizomes. We assessed bamboo water transport in three big clumpy bamboo species by deuterium tracing. The tracer was injected into the base of established culms, and water samples were collected from leaves of the labeled culms and from neighboring culms. From the base of labeled culms to their leaves, the average tracer arrival time across species was 1.2 days, maximum tracer concentration was reached after 1.8 days, and the tracer residence time was 5.6 days. Sap velocities were high (13.9 m d−1). Daily culm water use rates estimated by the tracer method versus rates measured by a calibrated sap flux method were highly correlated (R2 = 0.94), but the tracer estimates were about 70% higher. Elevated deuterium concentrations in studied neighbor culms point to deuterium transfer among culms, which may explain the difference in culm water use estimates. We found no differences in deuterium concentrations between neighbor-established and neighbor freshly sprouted culms of a given species. In two species, elevated concentrations in both neighbor-established and neighbor freshly sprouted culms were observed over an extended period. An applied mixing model suggests that five neighbor culms received labeled water. In contrast, for the third species, elevated concentrations in neighbor culms were only observed at the earliest sampling date after labeling. This could indicate that there was only short-term transfer and that the tracer was distributed more widely across the rhizome network. In conclusion, our deuterium tracing experiments point to water transfer among culms, but with species-specific differences.
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    • Journal Article

      Transcriptome profiling in Camellia japonica var. decumbens for the discovery of genes involved in chilling tolerance under cold stress 

      Wu, Yawen; Müller, Markus; Bai, Tian; Yao, Shunyang; Gailing, Oliver; Liu, Zhen
      Annals of Forest Research 2014; 62(1)
      Camellia japonica var. decumbens is a naturally occurring highly cold resistant variety of Camellia japonica which is suitable for snowy and cold regions. However, the underlying cold-adaptive mechanisms associated with gene regulation have been poorly investigated. We analyzed the transcriptomic changes caused by cold stress in a cold-tolerant accession. Samples were collected at the end of each temperature treatment (T1, T3, T5, T7 and T9 represent the temperatures 25°C, 0°C, -4°C, -8°C and -12°C, respectively). Sample T1 at 25°C was used as control. Based on transcriptome analysis, 2828, 2384, 3099 and 3075 differentially expressed genes (DEGs) were up-regulated, and 3184, 2592, 2373 and 2615 DEGs were down-regulated by analyzing T3/T1, T5/T1, T7/T1 and T9/T1, respectively. A gene ontology (GO) analysis revealed an enrichment of GO terms such as response to stimulus, metabolic process, catalytic activity or binding. Out of the larger number of DEGs, 67 functional and regulatory DEGs stood out, since they were functionally characterized in other models. These genes are cold-responsive transcription factors (26) or involved in cold sensor or signal transduction (17) and in the stabilization of the plasma membrane and osmosensing response (24). These results suggest rapid and multiple molecular mechanisms of perception, transduction and responses to cold stress in cold acclimation of Camellia japonica var. decumbens. They could also serve as a valuable resource for relevant research on cold-tolerance and help to explore cold-related genes to foster the understanding of low-temperature tolerance and plant-environment interactions.
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    • Journal Article

      Seasonal drivers of understorey temperature buffering in temperate deciduous forests across Europe 

      Zellweger, Florian; Coomes, David; Lenoir, Jonathan; Depauw, Leen; Maes, Sybryn L.; Wulf, Monika; Kirby, Keith J.; Brunet, Jörg; Kopecký, Martin; Máliš, František; et al.
      Schmidt, WolfgangHeinrichs, Steffiden Ouden, JanJaroszewicz, BogdanBuyse, GauthierSpicher, FabienVerheyen, KrisDe Frenne, Pieter
      Global Ecology and Biogeography 2019; 28(12) p.1774-1786
      Aim: Forest understorey microclimates are often buffered against extreme heat or cold, with important implications for the organisms living in these environments. We quantified seasonal effects of understorey microclimate predictors describing canopy structure, canopy composition and topography (i.e., local factors) and the forest patch size and distance to the coast (i.e., landscape factors). Location: Temperate forests in Europe. Time period: 2017–2018. Major taxa studied: Woody plants. Methods: We combined data from a microclimate sensor network with weather‐ station records to calculate the difference, or offset, between temperatures meas‐ ured inside and outside forests. We used regression analysis to study the effects of local and landscape factors on the seasonal offset of minimum, mean and maximum temperatures.
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    • Journal Article

      Global effects of non‐native tree species on multiple ecosystem services 

      Castro‐Díez, Pilar; Vaz, Ana Sofia; Silva, Joaquim S.; Loo, Marcela; Alonso, Álvaro; Aponte, Cristina; Bayón, Álvaro; Bellingham, Peter J.; Chiuffo, Mariana C.; DiManno, Nicole; et al.
      Julian, KahuaKandert, SusannePorta, Nicola LaMarchante, HéliaMaule, Hamish G.Mayfield, Margaret M.Metcalfe, DanielMonteverdi, M. CristinaNúñez, Martín A.Ostertag, RebeccaParker, Ingrid M.Peltzer, Duane A.Potgieter, Luke J.Raymundo, MaiaRayome, DonaldReisman‐Berman, OrnaRichardson, David M.Roos, Ruben E.Saldaña, AsunciónShackleton, Ross T.Torres, AgostinaTrudgen, MelindaUrban, JosefVicente, Joana R.Vilà, MontserratYlioja, TiinaZenni, Rafael D.Godoy, Oscar
      Biological Reviews(94) p.1477-1501
      Non-native tree (NNT) species have been transported worldwide to create or enhance services that are fundamental for human well-being, such as timber provision, erosion control or ornamental value; yet NNTs can also produce undesired effects, such as fire proneness or pollen allergenicity. Despite the variety of effects that NNTs have on multiple ecosystem services, a global quantitative assessment of their costs and benefits is still lacking. Such information is critical for decision-making, management and sustainable exploitation of NNTs. We present here a global assessment of NNT effects on the three main categories of ecosystem services, including regulating (RES), provisioning (PES) and cultural services (CES), and on an ecosystem disservice (EDS), i.e. pollen allergenicity. By searching the scientific literature, country forestry reports, and social media, we compiled a global data set of 1683 case studies from over 125 NNT species, covering 44 countries, all continents but Antarctica, and seven biomes. Using different meta-analysis techniques, we found that, while NNTs increase most RES (e.g. climate regulation, soil erosion control, fertility and formation), they decrease PES (e.g. NNTs contribute less than native trees to global timber provision). Also, they have different effects on CES (e.g. increase aesthetic values but decrease scientific interest), and no effect on the EDS considered. NNT effects on each ecosystem (dis)service showed a strong context dependency, varying across NNT types, biomes and socio-economic conditions. For instance, some RES are increased more by NNTs able to fix atmospheric nitrogen, and when the ecosystem is located in low-latitude biomes; some CES are increased more by NNTs in less-wealthy countries or in countries with higher gross domestic products. The effects of NNTs on several ecosystem (dis)services exhibited some synergies (e.g. among soil fertility, soil formation and climate regulation or between aesthetic values and pollen allergenicity), but also trade-offs (e.g. between fire regulation and soil erosion control). Our analyses provide a quantitative understanding of the complex synergies, trade-offs and context dependencies involved for the effects of NNTs that is essential for attaining a sustained provision of ecosystem services.
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    • Journal Article

      Response of Beech (Fagus sylvatica L.) Trees to Competition—New Insights from Using Fractal Analysis 

      Dorji; Annighöfer; Ammer; Seidel
      Remote Sensing 2019; 11(22)
      Individual tree architecture and the composition of tree species play a vital role for many ecosystem functions and services provided by a forest, such as timber value, habitat diversity, and ecosystem resilience. However, knowledge is limited when it comes to understanding how tree architecture changes in response to competition. Using 3D-laser scanning data from the German Biodiversity Exploratories, we investigated the detailed three-dimensional architecture of 24 beech (Fagus sylvatica L.) trees that grew under different levels of competition pressure. We created detailed quantitative structure models (QSMs) for all study trees to describe their branching architecture. Furthermore, structural complexity and architectural self-similarity were measured using the box-dimension approach from fractal analysis. Relating these measures to the strength of competition, the trees are exposed to reveal strong responses for a wide range of tree architectural measures indicating that competition strongly changes the branching architecture of trees. The strongest response to competition (rho = −0.78) was observed for a new measure introduced here, the intercept of the regression used to determine the box-dimension. This measure was discovered as an integrating descriptor of the size of the complexity-bearing part of the tree, namely the crown, and proven to be even more sensitive to competition than the box-dimension itself. Future studies may use fractal analysis to investigate and quantify the response of tree individuals to competition.
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    • Journal Article

      Response of Four Tree Species to Changing Climate in a Moisture-Limited Area of South Siberia 

      Babushkina, Elena A.; Zhirnova, Dina F.; Belokopytova, Liliana V.; Tychkov, Ivan I.; Vaganov, Eugene A.; Krutovsky, Konstantin V.
      Forests 2019; 10(11): Art. 999
      The response of vegetation to climate change is of special interest in regions where rapid warming is coupled with moisture deficit. This raises the question of the limits in plants’ acclimation ability and the consequent shifts of the vegetation cover. Radial growth dynamics and climatic response were studied in Scots pine (Pinus sylvestris L.), Siberian larch (Larix sibirica Ledeb.), and silver birch (Betula pendula Roth.) in the forest-steppe, and for Siberian elm (Ulmus pumila L.) in the steppe of South Siberia, as indicators of vegetation state and dynamics. Climate–growth relationships were analyzed by the following two approaches: (1) correlations between tree-ring width chronologies and short-term moving climatic series, and (2) optimization of the parameters of the Vaganov–Shashkin tree growth simulation model to assess the ecophysiological characteristics of species. Regional warming was accompanied by a slower increase of the average moisture deficit, but not in the severity of droughts. In the forest-steppe, the trees demonstrated stable growth and responded to the May–July climate. In the steppe, elm was limited by moisture deficit in May–beginning of June, during the peak water deficit. The forest-steppe stands were apparently acclimated successfully to the current climatic trends. It seems that elm was able to counter the water deficit, likely through its capacity to regulate transpiration by the stomatal morphology and xylem structure, using most of the stem as a water reservoir; earlier onset; and high growth rate, and these physiological traits may provide advantages to this species, leading to its expansion in steppes.
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      The Forest Policies of ASEAN and Montréal Process: Comparing Highly and Weakly Formalized Regional Regimes 

      Jeon, Sohui; Kumar Sarker, Pradip; Giessen, Lukas
      Forests 2019; 10(10): Art. 929
      Forests are governed by a combination of sub-national and national as well as global and regional regimes. Comparing the institutional variation of regional regimes, including their degrees of formalization, is gaining attention of studies on regionalism in International Relations. This study attempts to analyse the ways in which the selected cases of the forest-related Association of Southeast Asian Nations (ASEAN) and forest-focused Montréal Process (MP) regional regimes may have synergetic overlaps or disparity in their institutional design and forest policy development. For this, we combined IR’s ‘rational institutional design’ theory and a policy analysis approach. Using a qualitative data approach, we analyzed key structure-related historical regime documents (e.g., charters) issued since the inception of both regimes, and their latest forest policy initiatives for the periods 2016–2025 (Strategic Plan of Action for ASEAN Cooperation on Forestry) and 2009–2015 (Conceptual Framework for the Montréal Process Strategic Action Plan) with all relevant policy documents since the adoption of current policies. Based on that, we pose the empirical questions of how both regimes illustrate governance structure (i.e., institutional design), and on the other hand how to explain regime forest policies coherently and consistently in terms of their high versus low degree of formality. The results show that institutional design is highly explanatory based on treaty and non-treaty regime formation as well as forest-related/focused regime formation with the synergistic sustainable forest management (SFM) issue that embraces deforestation and forest degradation, biodiversity, timber certification, and greenhouse gas emission. Additionally, the results suggest that the policy goals adopted by both regimes are coherent and consistent based on the full set of policy elements. Concerning the remedy for fragmented global forest governance arrangements, both regimes would be an example of practicing SFM-focused policies with the incorporation of forest-related policy elements into a larger governance assemblage dealing with issues such as biodiversity conservation or climate change mitigation.
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      Drivers of the relative richness of naturalized and invasive plant species on Earth 

      Essl, Franz; Dawson, Wayne; Kreft, Holger; Pergl, Jan; Pyšek, Petr; Van Kleunen, Mark; Weigelt, Patrick; Mang, Thomas; Dullinger, Stefan; Lenzner, Bernd; et al.
      Moser, DietmarMaurel, NoëlieSeebens, HannoStein, AnkeWeber, EwaldChatelain, CyrilleInderjitGenovesi, PieroKartesz, JohnMorozova, OlgaNishino, MisakoNowak, Pauline MPagad, ShyamaShu, Wen-ShengWinter, Marten
      AoB PLANTS 2019; 11(5)
      Biological invasions are a defining feature of the Anthropocene, but the factors that determine the spatially uneven distribution of alien plant species are still poorly understood. Here, we present the first global analysis of the effects of biogeographic factors, the physical environment and socio-economy on the richness of naturalized and invasive alien plants. We used generalized linear mixed-effects models and variation partitioning to disentangle the relative importance of individual factors, and, more broadly, of biogeography, physical environment and socio-economy. As measures of the magnitude of permanent anthropogenic additions to the regional species pool and of species with negative environmental impacts, we calculated the relative richness of naturalized (= RRN) and invasive (= RRI) alien plant species numbers adjusted for the number of native species in 838 terrestrial regions. Socio-economic factors (per-capita gross domestic product (GDP), population density, proportion of agricultural land) were more important in explaining RRI (~50 % of the explained variation) than RRN (~40 %). Warm-temperate and (sub)tropical regions have higher RRN than tropical or cooler regions. We found that socio-economic pressures are more relevant for invasive than for naturalized species richness. The expectation that the southern hemisphere is more invaded than the northern hemisphere was confirmed only for RRN on islands, but not for mainland regions nor for RRI. On average, islands have ~6-fold RRN, and >3-fold RRI compared to mainland regions. Eighty-two islands (=26 % of all islands) harbour more naturalized alien than native plants. Our findings challenge the widely held expectation that socio-economic pressures are more relevant for plant naturalization than for invasive plants. To meet international biodiversity targets and halt the detrimental consequences of plant invasions, it is essential to disrupt the connection between socio-economic development and plant invasions by improving pathway management, early detection and rapid response.
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      Effects of forest‐use intensity on vascular epiphyte diversity along an elevational gradient 

      Guzmán‐Jacob, Valeria; Zotz, Gerhard; Craven, Dylan; Taylor, Amanda; Krömer, Thorsten; Monge‐González, María Leticia; Kreft, Holger
      Diversity and Distributions
      Aim: Understanding patterns of tropical plant diversity and their vulnerability to anthropogenic disturbance at different spatial scales remains a great challenge in ecology and conservation. Here, we study how the effects of forest‐use intensity on vascular epiphyte diversity vary along a tropical elevational gradient. Location: 3,500‐m elevational gradient along the eastern slopes of Cofre de Perote, Mexico. Methods: We studied the effects of forest‐use intensity on alpha, beta and gamma diversity of vascular epiphyte assemblages in old‐growth, degraded and secondary forests at eight study sites at 500‐m intervals along the elevational gradient. At each elevation and in each of the three forest‐use intensity levels, we established five 400‐m2 plots yielding a total of 120 plots. Results: Interactive effects of elevation and forest‐use intensity strongly impacted local‐scale patterns of vascular epiphyte diversity. Species diversity peaked at 500 as well as 1,500 m above sea level, which deviates from the previously reported humpshaped pattern. In most cases, alpha diversity did not differ significantly among forest‐ use intensity levels. However, gamma diversity was always lower in secondary forests compared to old‐growth forests across the entire elevational gradient. Within each elevational belt, beta diversity was dominated by species turnover along the forest‐use intensity gradient in the lowlands and declined with increasing elevation, where community composition became increasingly nested. Along the elevational gradient, the spatial turnover of vascular epiphyte community composition was similar among forest‐use intensity levels. Main conclusions: Our results reveal a strong interaction between forest‐use intensity and elevation, making it difficult to extrapolate findings from one elevational belt to another. Our findings highlight the value of old‐growth forest for epiphyte diversity, but also show that degraded and secondary forests—depending on the elevational belt—may maintain a high species diversity and thus play an important role in conservation planning.
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    • Journal Article

      Analyzing the relationship between historic canopy dynamics and current plant species diversity in the herb layer of temperate forests using long-term Landsat time series 

      Graf, Wanda; Kleinn, Christoph; Schall, Peter; Nauss, Thomas; Detsch, Florian; Magdon, Paul
      Remote Sensing of Environment 2019; 232: Art. 111305
      Current plant species diversity of the forest herb layer is influenced by site conditions, seed banks, stand age and historic canopy dynamics, induced for example by natural and anthropogenic disturbances. Long-term Landsat time series allow for analyzing forest canopy dynamics over several decades at a spatial resolution of 30 m. These dynamics have not been related to plant diversity in the herb layer of forests yet. Here, we related canopy layer dynamics of 132 one hectare temperate forest plots derived from Landsat time series (1985–2015) to herb layer plant species diversity observed in 2015. To quantitatively characterize the dynamics in the canopy over this period, we applied Symbolic Aggregate ApproXimation representation (SAX) to yearly NDVI time series of the plots and calculated the frequency of the representations of similar time series patterns, hereafter called SAX-metrics. We used the SAX-metrics as predictors to estimate with beta regression models the Simpson's diversity index of the herb layer of our forest plots subdivided into six forest types. Models including SAX-metrics, describing abrupt decreases in NDVI, and high, medium, or low NDVI values had pseudo R2 between 0.13 and 0.63. We conclude that disturbances, canopy closure, as well as stand age, as represented in NDVI time series, influence the diversity in the herb layer in five of the six examined forest types. Our study shows that information on historic canopy dynamics, detected from Landsat time series, can contribute to a better understanding of current herb layer diversity in some forest types. This study gives first indications on the potential of temporal metrics of Landsat time series in biodiversity research.
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