Refine
Year of publication
Language
- English (53) (remove)
Keywords
- climate change (6)
- nitrogen deposition (5)
- Climate change (4)
- biodiversity (4)
- dispersal (4)
- Latitudinal gradient (3)
- disturbance (3)
- epizoochory (3)
- forest management (3)
- forestREplot (3)
- landscape diversity (3)
- plant diversity (3)
- seed bank (3)
- species assembly (3)
- temperature (3)
- wetland vegetation (3)
- Acer platanoides (2)
- Acer pseudoplatanus (2)
- Canopy (2)
- Disturbance (2)
- Global change (2)
- Global environmental change (2)
- Host-plant quality (2)
- Melampyrum pratense (2)
- Milium effusum (2)
- NE Germany (2)
- Nitrogen-limitation hypothesis (2)
- Rearing experiment (2)
- latitude (2)
- life‐history traits (2)
- local adaptation (2)
- nutrient stoichiometry (2)
- seed dispersal (2)
- seed provisioning (2)
- sexual reproduction (2)
- species richness (2)
- wood anemone (2)
- (semi-)permanent plots (1)
- <i>Fusarium oxysporum</i> (1)
- <i>Zygogonium ericetorum</i> (1)
- Above-ground (1)
- Acer (1)
- Aglais (1)
- Agricultural fertilization (1)
- Agricultural landscapes (1)
- Amur River (1)
- Ancient forest (1)
- Anemone nemorosa (1)
- Base cations (1)
- Below-ground (1)
- Biogeography (1)
- Bird species richness (1)
- Brandenburg (1)
- CLSM (1)
- CSR-strategies (1)
- Calcareous grassland (1)
- Canopy closure (1)
- Cell structures (1)
- Chronosequence (1)
- Clonal growth (1)
- Collection date (1)
- Community ecology (1)
- Competition (1)
- Confocal laser scanning microscopy (1)
- Coppice (1)
- Cover abundance (1)
- Cryptogams (1)
- Decomposition (1)
- Dendrochronology (1)
- Diaspore morphology (1)
- Diasporenmorphologie (1)
- Diversity (1)
- Ellenberg indicator values (1)
- Epizoochorie (1)
- Eutrophication (1)
- Fagus (1)
- Fertilization (1)
- Fire frequency (1)
- Forest species (1)
- Forest understorey (1)
- Fragmentation (1)
- Fraxinus (1)
- Functional trait diversity (1)
- Germination (1)
- Habitat fragmentation (1)
- Herb layer (1)
- High forest (1)
- Interactive effects (1)
- Intraspecific variation (1)
- Isolation (1)
- Kettle holes (1)
- Landscape connectivity (1)
- Landscape eutrophication (1)
- Life history traits (1)
- Light availability (1)
- Litter raking (1)
- Macroclimatic gradient (1)
- Multi-scale analysis (1)
- NWEurope (1)
- Naturally rare species (1)
- Nitrogen deposition (1)
- Nutrient cycling (1)
- Pattern-oriented parameter estimation (1)
- Phenotypic plasticity (1)
- Phosphorus (1)
- Pinus sylvestris (1)
- Plant community (1)
- Plant conservation (1)
- Post-agricultural forest (1)
- Precipitation (1)
- Quercus (1)
- Recently rare species (1)
- Regeneration (1)
- Reh (1)
- Seed provenance (1)
- Seed traits (1)
- Shannon diversity (1)
- Soil fertility (1)
- Spatiotemporal resurvey data (1)
- Species co-existence (1)
- Species diversity (1)
- Species traits (1)
- Sphagnum magellanicum (1)
- Stachys sylvatica (1)
- Storage effect (1)
- Surface preparation (1)
- Sus scrofa (1)
- Taxonomic position (1)
- Temperate forest (1)
- Temperature (1)
- Tree regeneration (1)
- Vegetation structure (1)
- Waldbodenpflanzen (1)
- Wetland species (1)
- Wildschwein (1)
- Wood anatomy (1)
- additive partitioning of biodiversity effects (1)
- artificial introduction (1)
- atmospheric deposition (1)
- atmospheric nitrogen deposition (1)
- basal area increment (1)
- biodiversity change (1)
- biological soil crust (1)
- cattle grazing (1)
- cell structure (1)
- climatic debt (1)
- colonization (1)
- common garden (1)
- common garden experiment (1)
- continuous pasture (1)
- dendroclimatology (1)
- desiccation tolerance (1)
- determinants of plant community diversity and structure (1)
- diaspore (1)
- diaspore morphology (1)
- diaspore weight (1)
- directed dispersal (1)
- dispersal of cryptogams (1)
- dispersal potential (1)
- disturbance regime (1)
- drought (1)
- dry grasslands (1)
- ecosystem services (1)
- ecosystem stability (1)
- electron microscopy (1)
- evenness (1)
- external dispersal (1)
- forest herbs (1)
- forest plant species (1)
- forest specialist (1)
- forest understorey (1)
- fragmentation (1)
- game browsing (1)
- generalist emergent group (1)
- growth chambers (1)
- herbaceous layer (1)
- historical ecology (1)
- homogenization (1)
- individual-based model (1)
- interspecific variation (1)
- intraspecific divergence (1)
- land use impact (1)
- large herbivores (1)
- large ungulate (1)
- latitudinal gradient (1)
- life history attributes (1)
- life-history traits (1)
- long-distance dispersal (1)
- lowland fen (1)
- management (1)
- management intensity (1)
- meadow (1)
- meta-analysis (1)
- multifactorial environmental change (1)
- myrmecochory (1)
- non-random dispersal (1)
- north-western Europe (1)
- northern peatlands (1)
- open-top chambers (1)
- organic farming (1)
- pH (1)
- phenotypic plasticity (1)
- plant community (1)
- plant functional traits (1)
- plant regeneration (1)
- plant-animal interaction (1)
- plant-climate interaction (1)
- population dynamics (1)
- pot experiment (1)
- quantitative wood anatomy (1)
- quasi-permanent plot (1)
- range edges (1)
- range shifts (1)
- re-survey (1)
- recruitment (1)
- reproduction (1)
- resurveys (1)
- roe deer (1)
- rotational pasture (1)
- secondary seed dispersal (1)
- seed (1)
- seed longevity (1)
- seed nitrogen (1)
- seed predation (1)
- seed production (1)
- seed quality (1)
- seedling establishment (1)
- shoot fragments (1)
- spatially explicit modelling (1)
- spatiotemporal resurvey data (1)
- species diversity (1)
- temperate deciduous forest (1)
- time lag (1)
- trampling (1)
- tree rings (1)
- tree-ring analysis (1)
- understory (1)
- vegetation resurvey (1)
- vegetative reproduction (1)
- wet grassland (1)
- wet grasslands (1)
- wetland ecosystems (1)
- wild boar (1)
- woodland herb (1)
Institute
- Institut für Biochemie und Biologie (53) (remove)
Significant effects of temperature on the reproductive output of the forest herb Anemone nemorosa L.
(2010)
Climate warming is already influencing plant migration in different parts of the world. Numerous models have been developed to forecast future plant distributions. Few studies, however, have investigated the potential effect of warming on the reproductive output of plants. Understorey forest herbs in particular, have received little attention in the debate on climate change impacts. This study focuses on the effect of temperature on sexual reproductive output (number of seeds, seed mass, germination percentage and seedling mass) of Anemone nemorosa L., a model species for slow colonizing herbaceous forest plants. We sampled seeds of A. nemorosa in populations along a 2400 km latitudinal gradient from northern France to northern Sweden during three growing seasons (2005,2006 and 2008). This study design allowed us to isolate the effects of accumulated temperature (Growing Degree Hours; GDH) from latitude and the local abiotic and biotic environment. Germination and seed sowing trials were performed in incubators, a greenhouse and under field conditions in a forest. Finally, we disentangled correlations between the different reproductive traits of A. nemorosa along the latitudinal gradient. We found a clear positive relationship between accumulated temperature and seed and seedling traits: reproductive output of A. nemorosa improved with increasing GDH along the latitudinal gradient. Seed mass and seedling mass, for instance, increased by 9.7% and 10.4%, respectively, for every 1000 degrees C h increase in GDH. We also derived strong correlations between several seed and seedling traits both under field conditions and in incubators. Our results indicate that seed mass, incubator-based germination percentage (Germ%(Inc)) and the output of germinable seeds (product of number of seeds and Germ%(Inc) divided by 100) from plants grown along a latitudinal gradient (i.e. at different temperature regimes) provide valuable proxies to parameterize key population processes in models. We conclude that (1) climate warming may have a pronounced positive impact on sexual reproduction of A. nemorosa and (2) climate models forecasting plant distributions would benefit from including the temperature sensitivity of key seed traits and population processes.
Plant communities are often dispersal-limited and zoochory can be an efficient mechanism for plants to colonize new patches of potentially suitable habitat. We predicted that seed dispersal by ungulates acts as an ecological filter - which differentially affects individuals according to their characteristics and shapes species assemblages - and that the filter varies according to the dispersal mechanism (endozoochory, fur-epizoochory and hoof-epizoochory). We conducted two-step individual participant data meta-analyses of 52 studies on plant dispersal by ungulates in fragmented landscapes, comparing eight plant traits and two habitat indicators between dispersed and non-dispersed plants. We found that ungulates dispersed at least 44% of the available plant species. Moreover, some plant traits and habitat indicators increased the likelihood for plant of being dispersed. Persistent or nitrophilous plant species from open habitats or bearing dry or elongated diaspores were more likely to be dispersed by ungulates, whatever the dispersal mechanism. In addition, endozoochory was more likely for diaspores bearing elongated appendages whereas epizoochory was more likely for diaspores released relatively high in vegetation. Hoof-epizoochory was more likely for light diaspores without hooked appendages. Fur-epizoochory was more likely for diaspores with appendages, particularly elongated or hooked ones. We thus observed a gradient of filtering effect among the three dispersal mechanisms. Endozoochory had an effect of rather weak intensity (impacting six plant characteristics with variations between ungulate-dispersed and non-dispersed plant species mostly below 25%), whereas hoof-epizoochory had a stronger effect (eight characteristics included five ones with above 75% variation), and fur-epizoochory an even stronger one (nine characteristics included six ones with above 75% variation). Our results demonstrate that seed dispersal by ungulates is an ecological filter whose intensity varies according to the dispersal mechanism considered. Ungulates can thus play a key role in plant community dynamics and have implications for plant spatial distribution patterns at multiple scales.
Understorey plant communities play a key role in the functioning of forest ecosystems. Under favourable environmental conditions, competitive understorey species may develop high abundances and influence important ecosystem processes such as tree regeneration. Thus, understanding and predicting the response of competitive understorey species as a function of changing environmental conditions is important for forest managers. In the absence of sufficient temporal data to quantify actual vegetation changes, space-for-time (SFT) substitution is often used, i.e. studies that use environmental gradients across space to infer vegetation responses to environmental change over time. Here we assess the validity of such SFT approaches and analysed 36 resurvey studies from ancient forests with low levels of recent disturbances across temperate Europe to assess how six competitive understorey plant species respond to gradients of overstorey cover, soil conditions, atmospheric N deposition and climatic conditions over space and time. The combination of historical and contemporary surveys allows (i) to test if observed contemporary patterns across space are consistent at the time of the historical survey, and, crucially, (ii) to assess whether changes in abundance over time given recorded environmental change match expectations from patterns recorded along environmental gradients in space. We found consistent spatial relationships at the two periods: local variation in soil variables and overstorey cover were the best predictors of individual species’ cover while interregional variation in coarse-scale variables, i.e. N deposition and climate, was less important. However, we found that our SFT approach could not accurately explain the large variation in abundance changes over time. We thus recommend to be cautious when using SFT substitution to infer species responses to temporal changes.
Gametophyte and thallus fragments, respectively, may be an important or even the only mode of reproduction for many bryophytes and lichens species. Until now especially birds and mammals have been identifi ed as potential animal dispersal vectors of fragments. This study investigates the dispersal of bryophyte and lichen fragments by red wood ants which build large nest mounds from plant material and are abundant in European coniferous forests. We sampled nest material from 25 nest mounds in fi ve different pine and spruce forest types in Germany and found numerous fragments of 20 bryophyte and ten lichen species. As they occurred on almost all studied mounds and often in large numbers we conclude that collecting cryptogam fragments as nest material is a characteristic feature for the Formica rufa group in coniferous forests. Species number and composition of fragments on mounds coincided with the epigeic vegetation around ant nests to a large extent: Almost all collected species were present in the vegetation, and dominant fragment species occurred in large amounts in the vicinity of ant nests. Lichen fragments were larger than bryophyte fragments. Certain life forms (weft-forming bryophytes, reindeer lichens) were accumulated on mounds, while others (tall turfs, cup-type Cladonia species) were discriminated, refl ecting fragmentation features of species. Collected fragments may regenerate to mature plants if nest mounds are abandoned, and especially if they are lost during transport over several metres. We conclude that dispersal of fragments by red wood ants contributes to maintain epigeic bryophyte and lichen diversity of coniferous forests by supporting colonisation after disturbances, which occur on different spatial and temporal scales.
Wildfires affect biodiversity at multiple levels. While vegetation is directly changed by fire events, animals are often indirectly affected through changes in habitat and food availability. Globally, fire frequency and the extent of fires are predicted to increase in the future. The impact of fire on the biodiversity of temperate wetlands has gained little attention so far. We compared species richness and abundance of plants and birds in burnt and unburnt areas in the Amur floodplain/Russian Far East in the year of fire and 1 year after. We also analysed vegetation recovery in relation to time since fire over a period of 18 years. Plant species richness was higher in burnt compared to unburnt plots in the year of the fire, but not in the year after. This suggests that fire has a positive short-term effect on plant diversity. Bird species richness and abundance were lower on burnt compared to unburnt plots in the year of the fire, but not in the year after. Over a period of 18 years, high fire frequency led to an increase in herb cover and a decrease in grass cover. We show that the effects on biodiversity are taxon- and species-specific. Fire management strategies in temperate wetlands should consider fire frequency as a key driving force of vegetation structure, with carry-over effects on higher trophic levels. Designing fire refuges, i.e., areas that do not burn annually, might locally be necessary to maintain high species richness.
Patterns of phenotypic trait variation in two temperate forest herbs along a broad climatic gradient
(2015)
Phenotypic trait variation plays a major role in the response of plants to global environmental change, particularly in species with low migration capabilities and recruitment success. However, little is known about the variation of functional traits within populations and about differences in this variation on larger spatial scales. In a first approach, we therefore related trait expression to climate and local environmental conditions, studying two temperate forest herbs, Milium effusum and Stachys sylvatica, along a similar to 1800-2500 km latitudinal gradient. Within each of 9-10 regions in six European countries, we collected data from six populations of each species and recorded several variables in each region (temperature, precipitation) and population (light availability, soil parameters). For each plant, we measured height, leaf area, specific leaf area, seed mass and the number of seeds and examined environmental effects on within-population trait variation as well as on trait means. Most importantly, trait variation differed both between and within populations. Species, however, differed in their response. Intrapopulation variation in Milium was consistently positively affected by higher mean temperatures and precipitation as well as by more fertile local soil conditions, suggesting that more productive conditions may select for larger phenotypic variation. In Stachys, particularly light availability positively influenced trait variation, whereas local soil conditions had no consistent effects. Generally, our study emphasises that intra-population variation may differ considerably across larger scales-due to phenotypic plasticity and/or underlying genetic diversity-possibly affecting species response to global environmental change.
Questions Has plant species richness in semi-natural grasslands changed over recent decades? Do the temporal trends of habitat specialists differ from those of habitat generalists? Has there been a homogenization of the grassland vegetation? Location Different regions in Germany and the UK. Methods We conducted a formal meta-analysis of re-survey vegetation studies of semi-natural grasslands. In total, 23 data sets were compiled, spanning up to 75 years between the surveys, including 13 data sets from wet grasslands, six from dry grasslands and four from other grassland types. Edaphic conditions were assessed using mean Ellenberg indicator values for soil moisture, nitrogen and pH. Changes in species richness and environmental variables were evaluated using response ratios. Results In most wet grasslands, total species richness declined over time, while habitat specialists almost completely vanished. The number of species losses increased with increasing time between the surveys and were associated with a strong decrease in soil moisture and higher soil nutrient contents. Wet grasslands in nature reserves showed no such changes or even opposite trends. In dry grasslands and other grassland types, total species richness did not consistently change, but the number or proportions of habitat specialists declined. There were also considerable changes in species composition, especially in wet grasslands that often have been converted into intensively managed, highly productive meadows or pastures. We did not find a general homogenization of the vegetation in any of the grassland types. Conclusions The results document the widespread deterioration of semi-natural grasslands, especially of those types that can easily be transformed to high production grasslands. The main causes for the loss of grassland specialists are changed management in combination with increased fertilization and nitrogen deposition. Dry grasslands are most resistant to change, but also show a long-term trend towards an increase in more mesotrophic species.
Myrmecochory, i.e. dispersal of seeds by ants towards and around their nests, plays an important role in temperate forests. Yet hardly any study has examined plant population spread over several years and the underlying joint contribution of a hierarchy of dispersal modes and plant demography. We used a seed-sowing approach with three replicates to examine colonization patterns of Melampyrum pratense, an annual myrmecochorous herb, in a mixed Scots pine forest in northeastern Germany. Using a spatially explicit individualbased (SEIB) model population patterns over 4 years were explained by short-distance transport of seeds by small ant species with high nest densities, resulting in random spread. However, plant distributions in the field after another 4 years were clearly deviating from model predictions. Mean annual spread rate increased from 0.9 m to 5.1 m per year, with a clear inhomogeneous component. Obviously, after a lag-phase of several years, non-random seed dispersal by large red wood ants (Formica rufa) was determining the species’ spread, thus resulting in stratified dispersal due to interactions with different-sized ant species. Hypotheses on stratified dispersal, on dispersal lag, and on non-random dispersal were verified using an extended SEIB model, by comparison of model outputs with field patterns (individual numbers, population areas, and maximum distances). Dispersal towards red wood ant nests together with seed loss during transport and redistribution around nests were essential features of the model extension. The observed lag-phase in the initiation of non-random, medium-distance transport was probably due to a change of ant behaviour towards a new food source of increasing importance, being a meaningful example for a lag-phase in local plant species invasion. The results demonstrate that field studies should check model predictions wherever possible. Future research will show whether or not the M. pratense–ant system is representative for migration patterns of similar animal dispersal systems after having crossed range edges by long-distance dispersal events.
Butterflies rank among the most threatened animal groups throughout Europe. However, current population trends differ among species. The nettle-feeding butterflies Aglais io and Aglais urticae cope successfully with the anthropogenic land-use change. Both species are assumed to be pre-adapted to higher nitrogen contents in their host plant, stinging nettle (Urtica dioica). However, it is currently unknown, whether this pre-adaptation enables both Aglais species to cope successfully or even to benefit from the excessive nitrogen availabilities in nettles growing in modern farmlands. For this reason, this study focused on the response of both Aglais species to unfertilized nettles compared to nettles receiving 150 or 300 kg N ha(-1) yr(-1) (i.e., common fertilizer quantities of modern-day agriculture). Fertilized nettles were characterized by higher nitrogen concentrations and lower C:N ratios compared to the control group. In both Aglais species, the individuals feeding on fertilized nettles had higher survival rates, shorter larval periods and heavier pupae and, in A. urticae also longer forewings. All these trait shifts are beneficial for the individuals, lowering their risk to die before reproduction and increasing their reproductive potential. These responses agree with the well-accepted nitrogen-limitation hypothesis predicting a positive relationship between the nitrogen content of the diet and the performance of herbivorous insects. Furthermore, our findings suggest that the increasing abundance of both Aglais species may result not only from the increasing spread of nettles into the farmland but also from changes in their quality due to the eutrophication of the landscape during recent decades.
The recent decline of Lepidoptera species strongly correlates with the increasing intensification of agriculture in Western and Central Europe. However, the effects of changed host-plant quality through agricultural fertilization on this insect group remain largely unexplored. For this reason, we tested the response of six common butterfly and moth species to host-plant fertilization using fertilizer quantities usually applied in agriculture. The larvae of the study species Coenonympha pamphilus, Lycaena phlaeas, Lycaena tityrus, Pararge aegeria, Rivula sericealis and Timandra comae were distributed according to a split-brood design to three host-plant treatments comprising one control treatment without fertilization and two fertilization treatments with an input of 150 and 300kgNha(-1)year(-1), respectively. In L.tityrus, we used two additional fertilization treatments with an input of 30 and 90kgNha(-1)year(-1), respectively. Fertilization increased the nitrogen concentration of both host-plant species, Rumex acetosella and Poa pratensis, and decreased the survival of larvae in all six Lepidoptera species by at least one-third, without clear differences between sorrel- and grass-feeding species. The declining survival rate in all species contradicts the well-accepted nitrogen-limitation hypothesis, which predicts a positive response in species performance to dietary nitrogen content. In contrast, this study presents the first evidence that current fertilization quantities in agriculture exceed the physiological tolerance of common Lepidoptera species. Our results suggest that (1) the negative effect of plant fertilization on Lepidoptera has previously been underestimated and (2) that it contributes to the range-wide decline of Lepidoptera.