Refine
Document Type
- Article (21)
Language
- English (21)
Has Fulltext
- yes (21)
Is part of the Bibliography
- no (21)
Keywords
- - (9)
- climate change (4)
- Baltic Sea (2)
- DNA barcoding (2)
- paludiculture (2)
- peatland (2)
- Bayesian sparse linear mixed model (1)
- Environmental Economics (1)
- Environmental and Conservation Psychology (1)
- Europe (1)
- European beech (1)
- Fagus sylvatica (1)
- Forest ecology (1)
- Michaelis–Menten function (1)
- Palaearctic grassland (1)
- Pantopoda (1)
- Pinus uncinata (1)
- Rügen (1)
- Schlei (1)
- Sphagnum farming (1)
- Sphagnum magellanicum (1)
- Zingst (1)
- alien invasive species (1)
- alpine (1)
- autumn (1)
- biological invasion (1)
- biomass productivity (1)
- bodden (1)
- broadleaves (1)
- bud dormancy (1)
- carbon balance (1)
- cell cycle arrest (1)
- climate extreme (1)
- climate sensitivity (1)
- climate warming (1)
- climate–growth relationships (1)
- cold edge (1)
- cold events (1)
- cross‐stress tolerance (1)
- cryptic species (1)
- dendrochronology (1)
- dendroecology (1)
- dendrometer (1)
- dendrophenotype (1)
- development (1)
- disturbance (1)
- drought (1)
- dry edge (1)
- ecosystem diversity (1)
- ecosystem functioning (1)
- endodormancy (1)
- fall (1)
- farming (1)
- forest ecology (1)
- genome size (1)
- genotype–phenotype associations (1)
- genotyping (1)
- genotyping‐by‐sequencing (1)
- gradient experiment (1)
- grassland ecosystem (1)
- growing media (1)
- growing season (1)
- growth dynamics (1)
- hydraulic conductivity (1)
- intraspecific trait variation (1)
- leaf phenology (1)
- leaf senescence (1)
- limbs (1)
- linear mixed model (1)
- local adaptation (1)
- logarithmic function (1)
- minimal area (1)
- minirhizotrons (1)
- money allocation (1)
- musculature (1)
- nested‐plot sampling (1)
- nitrogen deficiency (1)
- nonlinear regression (1)
- peat moss (1)
- peatland restoration (1)
- peatlands (1)
- phenotypic plasticity (1)
- phylogeography (1)
- plant biodiversity (1)
- plant–environment interaction (1)
- power law (1)
- productivity (1)
- protists (1)
- rating scale (1)
- reciprocal transplantation experiment (1)
- recovery (1)
- regeneration (1)
- renewable resource (1)
- reproductive ecology (1)
- resilience (1)
- resistance (1)
- rest break (1)
- rewetting (1)
- root phenology (1)
- salinity (1)
- scaling law (1)
- sea spider (1)
- seed germination (1)
- seed rain (1)
- self-organization (1)
- simulation (1)
- slime molds (1)
- soil temperature (1)
- species persistence (1)
- species–area relationship (SAR) (1)
- sustainable land use (1)
- temperate forest (1)
- temperate trees (1)
- tissue chemical composition (1)
- tomato (1)
- tree growth (1)
- treeline ecotone (1)
- tree‐ring network (1)
- utilization (1)
- vapour pressure deficit (1)
- vegetation relevés (1)
- water table (1)
- winter climate (1)
- winter ecology (1)
- δ (1)
Institute
- Institut für Botanik und Landschaftsökologie & Botanischer Garten (21) (remove)
Publisher
- Wiley (21) (remove)
Abstract
Aim
Species–area relationships (SARs) are fundamental scaling laws in ecology although their shape is still disputed. At larger areas, power laws best represent SARs. Yet, it remains unclear whether SARs follow other shapes at finer spatial grains in continuous vegetation. We asked which function describes SARs best at small grains and explored how sampling methodology or the environment influence SAR shape.
Location
Palaearctic grasslands and other non‐forested habitats.
Taxa
Vascular plants, bryophytes and lichens.
Methods
We used the GrassPlot database, containing standardized vegetation‐plot data from vascular plants, bryophytes and lichens spanning a wide range of grassland types throughout the Palaearctic and including 2,057 nested‐plot series with at least seven grain sizes ranging from 1 cm2 to 1,024 m2. Using nonlinear regression, we assessed the appropriateness of different SAR functions (power, power quadratic, power breakpoint, logarithmic, Michaelis–Menten). Based on AICc, we tested whether the ranking of functions differed among taxonomic groups, methodological settings, biomes or vegetation types.
Results
The power function was the most suitable function across the studied taxonomic groups. The superiority of this function increased from lichens to bryophytes to vascular plants to all three taxonomic groups together. The sampling method was highly influential as rooted presence sampling decreased the performance of the power function. By contrast, biome and vegetation type had practically no influence on the superiority of the power law.
Main conclusions
We conclude that SARs of sessile organisms at smaller spatial grains are best approximated by a power function. This coincides with several other comprehensive studies of SARs at different grain sizes and for different taxa, thus supporting the general appropriateness of the power function for modelling species diversity over a wide range of grain sizes. The poor performance of the Michaelis–Menten function demonstrates that richness within plant communities generally does not approach any saturation, thus calling into question the concept of minimal area.
Abstract
Higher biodiversity can stabilize the productivity and functioning of grassland communities when subjected to extreme climatic events. The positive biodiversity–stability relationship emerges via increased resistance and/or recovery to these events. However, invader presence might disrupt this diversity–stability relationship by altering biotic interactions. Investigating such disruptions is important given that invasion by non‐native species and extreme climatic events are expected to increase in the future due to anthropogenic pressure. Here we present one of the first multisite invader × biodiversity × drought manipulation experiment to examine combined effects of biodiversity and invasion on drought resistance and recovery at three semi‐natural grassland sites across Europe. The stability of biomass production to an extreme drought manipulation (100% rainfall reduction; BE: 88 days, BG: 85 days, DE: 76 days) was quantified in field mesocosms with a richness gradient of 1, 3, and 6 species and three invasion treatments (no invader, Lupinus polyphyllus, Senecio inaequidens). Our results suggest that biodiversity stabilized community productivity by increasing the ability of native species to recover from extreme drought events. However, invader presence turned the positive and stabilizing effects of diversity on native species recovery into a neutral relationship. This effect was independent of the two invader's own capacity to recover from an extreme drought event. In summary, we found that invader presence may disrupt how native community interactions lead to stability of ecosystems in response to extreme climatic events. Consequently, the interaction of three global change drivers, climate extremes, diversity decline, and invasive species, may exacerbate their effects on ecosystem functioning.
Sphagnum growth under N saturation: interactive effects of water level and P or K fertilization
(2020)
Abstract
Sphagnum biomass is a promising material that could be used as a substitute for peat in growing media and can be sustainably produced by converting existing drainage‐based peatland agriculture into wet, climate‐friendly agriculture (paludiculture). Our study focuses on yield maximization of Sphagnum as a crop.
We tested the effects of three water level regimes and of phosphorus or potassium fertilization on the growth of four Sphagnum species (S. papillosum, S. palustre, S. fimbriatum, S. fallax). To simulate field conditions in Central and Western Europe we carried out a glasshouse experiment under nitrogen‐saturated conditions.
A constant high water table (remaining at 2 cm below capitulum during growth) led to highest productivity for all tested species. Water table fluctuations between 2 and 9 cm below capitulum during growth and a water level 2 cm below capitulum at the start but falling relatively during plant growth led to significantly lower productivity. Fertilization had no effect on Sphagnum growth under conditions with high atmospheric deposition such as in NW Germany (38 kg N, 0.3 kg P, 7.6 kg K·ha−1·year−1).
Large‐scale maximization of Sphagnum yields requires precise water management, with water tables just below the capitula and rising with Sphagnum growth. The nutrient load in large areas of Central and Western Europe from atmospheric deposition and irrigation water is high but, with an optimal water supply, does not hamper Sphagnum growth, at least not of regional provenances of Sphagnum.
Summary
Sphagnum farming can substitute peat with renewable biomass and thus help mitigate climate change. Large volumes of the required founder material can only be supplied sustainably by axenic cultivation in bioreactors.
We established axenic in vitro cultures from sporophytes of 19 Sphagnum species collected in Austria, Germany, Latvia, the Netherlands, Russia, and Sweden: S. angustifolium, S. balticum, S. capillifolium, S. centrale, S. compactum, S. cuspidatum, S. fallax, S. fimbriatum, S. fuscum, S. lindbergii, S. medium/divinum, S. palustre, S. papillosum, S. rubellum, S. russowii, S. squarrosum, S. subnitens, S. subfulvum and S. warnstorfii. These species cover five of the six European Sphagnum subgenera; namely, Acutifolia, Cuspidata, Rigida, Sphagnum and Squarrosa.
Their growth was measured in suspension cultures, whereas their ploidy was determined by flow cytometry and compared with the genome size of Physcomitrella patens. We identified haploid and diploid Sphagnum species, found that their cells are predominantly arrested in the G1 phase of the cell cycle, and did not find a correlation between plant productivity and ploidy. DNA barcoding was achieved by sequencing introns of the BRK1 genes.
With this collection, high‐quality founder material for diverse large‐scale applications, but also for basic Sphagnum research, is available from the International Moss Stock Center.
Abstract
Aims
Pinus uncinata is the major treeline‐forming species in the Pyrenees. Yet, the role of its reproduction and dispersal as drivers of treeline dynamics remains unknown. Here we quantify seed production, dispersal and germination changes along the elevation gradient to assess whether they may constrain the foreseen treeline advance in the Pyrenees.
Location
Central Pyrenees, Catalonia, NE Spain.
Methods
We established four plots along an elevation gradient from the closed subalpine forest to the krummholz zone at five study sites. In each plot, we collected cones from five to six trees, measured their length, and triggered their opening in the laboratory to count the number of empty seeds and the number and weight of full seeds. We used the collected seeds in a germination experiment under controlled conditions in growth chambers. Additionally, we installed seed traps along the forest–alpine grassland transition to measure seed rain for three consecutive years in three of the study sites.
Results
The number of full seeds per cone decreased along the elevation gradient and was correlated with cone length. However, the proportion of full seeds per cone and their weight did not differ between elevation positions. Seed rain decreased drastically with elevation and no seeds arrived into the alpine grassland traps consistently across study years. Although germination success did not significantly differ between elevation provenances (i.e., elevation position of origin), we found significant differences in germination dynamics between study sites and between elevation provenances within sites.
Conclusions
Our results indicate that whereas the viability of Pinus uncinata seeds is not limited by elevation, seed production and dispersal are constraining the ongoing rates of treeline advance in the Pyrenees.
Abstract
Aim
Climate limits the potential distribution ranges of species. Establishment and growth of individuals at range margins is assumed to be more limited by extreme events such as drought or frost events than in the centre of their range. We explore whether the growth of beech is more sensitive to drought towards the dry distribution margin and more sensitive to frost towards the cold distribution margin. Furthermore, we aim to gain insight into the adaptive potential of beech towards both the dry and cold distribution margins.
Location
European gradient from the dry (Spain) to the cold (Poland, Sweden) distribution margin of beech.
Taxon
European beech (Fagus sylvatica L.).
Methods
We applied a range‐wide dendroecological study to analyse spatial and temporal trends in climate–growth relationships. We further investigated negative growth anomalies and growth synchrony towards the range margins.
Results
We found beech to be drought sensitive across its whole range, except at the dry distribution margin. Furthermore, sensitivity to winter temperature was not found in the centre or at the cold distribution margin, but at the southern distribution margin. Growth synchrony was lower at the dry than at the cold distribution margin.
Main conclusions
Beech seems to be adapted to drought at the dry distribution margin with a high adaptive potential indicated by the lowest growth synchrony along the gradient. At the cold distribution margin, cold events in winter and spring were less important for growth than drought. Still, the importance of spring frost for beech growth appears to increase in recent decades. Considering a projected north‐eastward shift of the distribution range, beech is likely facing drought stress in combination with spring frost risk at the cold margin which could lead to a hampered range expansion.
Abstract
The role of future forests in global biogeochemical cycles will depend on how different tree species respond to climate. Interpreting the response of forest growth to climate change requires an understanding of the temporal and spatial patterns of seasonal climatic influences on the growth of common tree species. We constructed a new network of 310 tree‐ring width chronologies from three common tree species (Quercus robur, Pinus sylvestris and Fagus sylvatica) collected for different ecological, management and climate purposes in the south Baltic Sea region at the border of three bioclimatic zones (temperate continental, oceanic, southern boreal). The major climate factors (temperature, precipitation, drought) affecting tree growth at monthly and seasonal scales were identified. Our analysis documents that 20th century Scots pine and deciduous species growth is generally controlled by different climate parameters, and that summer moisture availability is increasingly important for the growth of deciduous species examined. We report changes in the influence of winter climate variables over the last decades, where a decreasing influence of late winter temperature on deciduous tree growth and an increasing influence of winter temperature on Scots pine growth was found. By comparing climate–growth responses for the 1943–1972 and 1973–2002 periods and characterizing site‐level growth response stability, a descriptive application of spatial segregation analysis distinguished sites with stable responses to dominant climate parameters (northeast of the study region), and sites that collectively showed unstable responses to winter climate (southeast of the study region). The findings presented here highlight the temporally unstable and nonuniform responses of tree growth to climate variability, and that there are geographical coherent regions where these changes are similar. Considering continued climate change in the future, our results provide important regional perspectives on recent broad‐scale climate–growth relationships for trees across the temperate to boreal forest transition around the south Baltic Sea.
Abstract
Climate change will lead to more frequent and severe drought periods which massively reduce crop production worldwide. Besides drought, nitrogen (N)‐deficiency is another critical threat to crop yield production. Drought and N‐deficiency both decrease photosynthesis and induce similar adaptive strategies such as longer roots, reduction of biomass, induction of reactive oxygen species (ROS), and antioxidative enzymes. Due to the overlapping response to N‐deficiency and drought, understanding the physiological and molecular mechanisms involved in cross‐stresses tolerance is crucial for breeding strategies and achieving multiple stress resistance and eventually more sustainable agriculture. The objective of this study was to investigate the effect of a mild N‐deficiency on drought stress tolerance of tomato plants (Solanum lycopersicum L., cv. Moneymaker). Various morphological and physiological parameters such as dry biomass, root length, water potential, SPAD values, stomatal conductance, and compatible solutes accumulation (proline and sugar) were analyzed. Moreover, the expression of ROS scavenging marker genes, cytosolic ASCORBATE PEROXIDASES (cAPX1, cAPX2, and cAPX3), were investigated. Our results showed that a former mild N‐deficiency (2 mM NO3−) enhances plant adaptive response to drought stress (4 days) when compared to the plants treated with adequate N (5 mM NO3−). The improved adaptive response was reflected in higher aboveground biomass, longer root, increased specific leaf weight, enhanced stomatal conductance (without reducing water content), and higher leaf sugar content. Moreover, the APX1 gene showed a higher expression level compared to control under N‐deficiency and in combination with drought in the leaf, after a one‐week recovery period. Our finding highlights a potentially positive link between a former mild N‐deficiency and subsequent drought stress response in tomato. Combining the morphological and physiological response with underlying gene regulatory networks under consecutive stress, provide a powerful tool for improving multiple stress resistance in tomato which can be further transferred to other economically important crops.
Abstract
Individuals of the marine chelicerate lineage Pycnogonida (sea spiders) show considerable regenerative capabilities after appendage injury or loss. In their natural habitats, especially the long legs of sea spiders are commonly lost and regenerated, as is evidenced by the frequent encounter of specimens with missing or miniature legs. In contrast to this, the collection of individuals with abnormally developed appendages or trunk regions is comparably rare. Here, we studied a remarkable malformation in a postlarval instar of the species Phoxichilidium femoratum (Rathke, 1799) and describe the external morphology and internal organization of the specimen using a combination of fluorescent histochemistry and scanning electron microscopy. The individual completely lacks the last trunk segment with leg pair 4 and the normally penultimate trunk segment bears only a single aberrant appendage resembling an extension of the anteroposterior body axis. Externally, the proximal units of the articulated appendage are unpaired, but further distally a bifurcation into two equally developed leg‐like branches is found. Three‐dimensional reconstruction of the musculature reveals components of two regular leg muscle sets in several of the proximal articles. This confirms interpretation of the entire appendage as a malformed leg and reveals an externally hidden paired organization along its entire proximodistal axis. To explain the origin of this unique malformation, early pioneering studies on the regenerative potential of pycnogonids are evaluated and (a) an injury‐induced partial fusion of the developing limb buds of leg pair 3, as well as (b) irregular leg regeneration following near complete loss of trunk segments 3 and 4 are discussed. Which of the two hypotheses is more realistic remains to be tested by dedicated experimental approaches. These will have to rely on pycnogonid species with established laboratory husbandry in order to overcome the limitations of the few short‐term regeneration studies performed to date.