Institut für Landschafts- und Pflanzenökologie

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Trade‐offs among restored ecosystem functions are context‐dependent in Mediterranean‐type regions
(2025) Fiedler, Sebastian; Perring, Michael P.; Monteiro, José A.; Branquinho, Cristina; Buzhdygan, Oksana; Cavieres, Lohengrin A.; Cleland, Elsa E.; Cortina‐Segarra, Jordi; Grünzweig, José M.; Holm, Jennifer A.; Irob, Katja; Keenan, Trevor F.; Köbel, Melanie; Maestre, Fernando T.; Pagel, Jörn; Rodríguez‐Ramírez, Natalia; Ruiz‐Benito, Paloma; Schurr, Frank M.; Sheffer, Efrat; Valencia, Enrique; Tietjen, Britta; Fiedler, Sebastian; Freie Universität Berlin, Theoretical Ecology, Institute of Biology, Berlin, Germany; Perring, Michael P.; UKCEH (UK Centre for Ecology and Hydrology), Environment Centre Wales, Bangor, UK; Monteiro, José A.; Freie Universität Berlin, Theoretical Ecology, Institute of Biology, Berlin, Germany; Branquinho, Cristina; cE3c – Centre for Ecology, Evolution and Environmental Changes & CHANGE – Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal; Buzhdygan, Oksana; Freie Universität Berlin, Theoretical Ecology, Institute of Biology, Berlin, Germany; Cavieres, Lohengrin A.; Departamento de Botánica, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción and Institute of Ecology and Biodiversity (IEB), Concepción, Chile; Cleland, Elsa E.; Ecology, Behavior & Evolution Department, University of California, San Diego, La Jolla, CA, USA; Cortina‐Segarra, Jordi; Department of Ecology and IMEM, University of Alicante, Alicante, Spain; Grünzweig, José M.; Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and Environment, the Hebrew University of Jerusalem, Rehovot, Israel; Holm, Jennifer A.; Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA; Irob, Katja; Freie Universität Berlin, Theoretical Ecology, Institute of Biology, Berlin, Germany; Keenan, Trevor F.; Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, Berkeley, CA, USA; Köbel, Melanie; cE3c – Centre for Ecology, Evolution and Environmental Changes & CHANGE – Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal; Maestre, Fernando T.; Environmental Sciences and Engineering, Biological and Environmental Science and Engineering 34 Division, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia; Pagel, Jörn; Institute of Landscape and Plant Ecology, University of Hohenheim, Stuttgart, Germany; Rodríguez‐Ramírez, Natalia; IMBE, Aix Marseille Université, Avignon Université, Marseille, France; Ruiz‐Benito, Paloma; Universidad de Alcalá, Grupo de Ecología y Restauración Forestal, Departamento de Ciencias de la Vida, Alcalá de Henares, Spain; Schurr, Frank M.; Institute of Landscape and Plant Ecology, University of Hohenheim, Stuttgart, Germany; Sheffer, Efrat; Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Food and Environment, the Hebrew University of Jerusalem, Rehovot, Israel; Valencia, Enrique; Departamento de Biodiversidad, Ecología y Evolución, Facultad de Ciencias Biológicas, Universidad Complutense de Madrid, Madrid, Spain; Tietjen, Britta; Freie Universität Berlin, Theoretical Ecology, Institute of Biology, Berlin, Germany
Global biodiversity hotspots, including Mediterranean‐type ecosystems worldwide, are highly threatened by global change that alters biodiversity, ecosystem functions, and services. Some restoration activities enhance ecosystem functions by reintroducing plant species based on known relationships between plant traits and ecosystem processes. Achieving multiple functions across different site conditions, however, requires understanding how abiotic factors like climate and soil, along with plant assemblages, influence ecosystem functions, including their trade‐offs and synergies. We used the ModEST ecosystem simulation model, which integrates carbon, water, and nutrient processes with plant traits, to assess the relationships between restored plant assemblages and ecosystem functions in Mediterranean‐type climates and soils. We investigated whether maximised carbon increment, water use efficiency, and nitrogen use efficiency, along with their trade‐offs and synergies, varied across different abiotic contexts. Further, we asked whether assemblages that maximised functions varied across environments and among these functions. We found that maximised ecosystem carbon increment and nitrogen use efficiency occurred under moist, warm conditions, while water use efficiency peaked under drier conditions. Generally, the assemblage that maximised one function differed from those for other maximised functions. Synergies were rare, except between water and nitrogen use efficiencies in loam soils across most climates. Trade‐offs among maximised functions were common, varying in strength with abiotic context and plant assemblages, and were more pronounced in sandy loam soils compared to clay‐rich soils. Our findings suggest that due to variation in abiotic conditions within and across Mediterranean‐type regions at the global scale, site‐specific plant assemblages are required to maximise ecosystem functions. Thus, lessons from a single site cannot be transferred to another site, even where the same plant functional types are available for restoration. Our simulation results offer valuable insights into potential ecosystem performance under specific abiotic conditions following restoration with particular plant functional types, thereby informing local restoration efforts.
Drought impacts on plant–soil carbon allocation - integrating future mean climatic conditions
(2025) Leyrer, Vinzent; Blum, Juliette; Marhan, Sven; Kandeler, Ellen; Zimmermann, Telse; Berauer, Bernd J.; Schweiger, Andreas H.; Canarini, Alberto; Richter, Andreas; Poll, Christian
Droughts affect soil microbial abundance and functions—key parameters of plant–soil carbon (C) allocation dynamics. However, the impact of drought may be modified by the mean climatic conditions to which the soil microbiome has previously been exposed. In a future warmer and drier world, effects of drought may therefore differ from those observed in studies that simulate drought under current climatic conditions. To investigate this, we used the field experiment ‘Hohenheim Climate Change,’ an arable field where predicted drier and warmer mean climatic conditions had been simulated for 12 years. In April 2021, we exposed this agroecosystem to 8 weeks of drought with subsequent rewetting. Before drought, at peak drought, and after rewetting, we pulse‐labelled winter wheat in situ with 13CO2 to trace recently assimilated C from plants to soil microorganisms and back to the atmosphere. Severe drought decreased soil respiration (−35%) and abundance of gram‐positive bacteria (−15%) but had no effect on gram‐negative bacteria, fungi, and total microbial biomass C. This pattern was not affected by the mean precipitation regime to which the microbes had been pre‐exposed. Reduced mean precipitation had, however, a legacy effect by decreasing the proportion of recently assimilated C allocated to the microbial biomass C pool (−50%). Apart from that, continuous soil warming was an important driver of C fluxes throughout our experiment, increasing plant biomass, root sugar concentration, labile C, and respiration. Warming also shifted microorganisms toward utilizing soil organic matter as a C source instead of recently assimilated compounds. Our study found that moderate shifts in mean precipitation patterns can impose a legacy on how plant‐derived C is allocated in the microbial biomass of a temperate agroecosystem during drought. The overarching effect of soil warming, however, suggests that how temperate agroecosystems respond to drought will mainly be affected by future temperature increases.
What acceleration data from wildlife collars and animal body mass tell us about seed dispersal
(2023) Buchmann, Carsten M.; Dreyling, Lukas; Constantin, Mihaela; Schurr, Frank M.
Background: The seeds of many plant species can be dispersed over long distances in animal fur (epizoochory). Quantifying epizoochory in the wild is, however, challenging, since it is difficult to measure the retention times of seeds in fur. These retention times depend on the acceleration that seeds experience and that can detach seeds from fur. Wildlife collars containing accelerometers may thus provide crucial information on epizoochorous seed dispersal. However, this is only the case if acceleration of the animal’s neck (where collars are attached) is informative of acceleration of the animal’s main body (where most seeds are transported). Methods: We used accelerometers to simultaneously measure acceleration at the neck, breast and the upper hind leg of 40 individuals of eight mammal species spanning a large range of body masses (26–867 kg). We then quantified maximum acceleration as the 95%-quantile of the resultant acceleration (of all measured values in data intervals of 5 s). Results: Maximum acceleration was comparable between the neck and breast but substantially higher at the hind leg. Maximum acceleration measured by neck collars and body mass jointly explained 81% of the variance in maximum acceleration of the breast and 62% of the variance in maximum acceleration of the leg. Conclusions: Acceleration measured by neck collars is informative of the acceleration experienced by seeds attached to other body parts (breast and leg). When combined with animal movement data and lab measurements of how fur acceleration affects seed release and retention times, widely used collar accelerometers can thus be used to assess distances of epizoochorous seed dispersal.
Significant links between photosynthetic capacity, atmospheric CO₂ and the diversification of C₃ plants during the last 80 million years
(2024) Schweiger, Andreas H.; Schweiger, Julienne M.‐I.
Changing CO₂ concentrations will continue to affect plant growth with consequences for ecosystem functioning. The adaptive capacity of C₃ photosynthesis to changing CO₂ concentrations is, however, insufficiently investigated so far. Here, we focused on the phylogenetic dynamics of maximum carboxylation rate (Vcmax) and maximum electron transport rate (Jmax)—two key determinants of photosynthetic capacity in C₃ plants—and their relation to deep-time dynamics in species diversification, speciation and atmospheric CO₂ concentrations during the last 80 million years. We observed positive relationships between photosynthetic capacity and species diversification as well as speciation rates. We furthermore observed a shift in the relationships between photosynthetic capacity, evolutionary dynamics and prehistoric CO₂ fluctuations about 30 million years ago. From this, we deduce strong links between photosynthetic capacity and evolutionary dynamics in C₃ plants. We furthermore conclude that low CO₂ environments in prehistory might have changed adaptive processes within the C₃ photosynthetic pathway.
Data on transgenerational memory effects of photosynthetic efficiency of twelve wheat varieties under elevated carbon dioxide concentration and reduced soil water availability
(2025) Berauer, Bernd J.; Chaudhary, Suraj; Kottmann, Lorenz; Schweiger, Andreas H.
This data represents ACi curves of twelve winter wheat varieties, which were grown under elevated and ambient CO2 concentrations within a FACE experiment and the subsequent F1 generation was exposed to ambient and elevated CO2 concentrations in a highly controlled environment using climate chambers. The 12 winter wheat genotypes (Triticum aestivum L.) were selected based on their susceptibilty to leaf rust (Puccinia triticina Eriks.) and Fusarium head blight (Fusarium graminearum Schwabe) according to the descriptive variety list of the German Federal Office of Plant Varietes (Beschreibende Sortenliste, Bundessortenamt 2024). The aim was to obtain a diverse set of varieties with the widest possible range of susceptibilities to leaf rust and fusarium head blight. Photosynthesis was measured using the novel Dynamic Assimilation Technique, thus not with the common steady-state approach. The individual wheat plants were measured twice, once under saturating soil water availability (θFC) and once under reduced soil water availability (θcsoil). θcsoil represents the gravimetric water content when the soil matric potential drops below the root matric potential, thus the onset of plant drought stress (sensu Cai et al. [2]). The photosynthesis data was used to fit ACi curves and extract the maximum Rubisco carboxylation rate [Vcmax], maximum rate of electron transport [Jmax] and dark respiration [Rd]. At both measurements we determined BBCH and plant height to quantify plant morphological development, as well as leaf water potential to quantify plant ecohydrologic status. At the end of the experiment, biomass was harvested and reported. Further, we provide environmental data of the climate chambers in use. Within the data repository, we provide comprehensive experimental data on the investigation of transgenerational memory effects on photosynthetic efficiency. We provide photosynthetic raw data as well as processed (merged) and derived (extracted ACi fit) data. Additionally, we provide the R-code to reproduce the calculation of the derived parameters. Data on transgenerational memory effects (that is, the influence of the parental environment on offspring phenotype and performance) are scarce, i.e. on the adaptive capacity of the photosynthetic apparatus. Thus, the data provided here can contribute to closing this gap. The highly controlled environment allows to closely investigate cause-effect relationships, thereby contributing to a mechanistic understanding of the transgenerational memory effects on photosynthetic efficiency and how this is altered by reduced soil water availability. By using a recently developed methodological approach, the data contributes to further investigate the quality of the method and establish it within the field of plant ecophysiology.
Same data, different analysts: variation in effect sizes due to analytical decisions in ecology and evolutionary biology
(2025) Gould, Elliot; Berauer, Bernd J.; Ernst, Ulrich Rainer; Zitomer, Rachel A.
Although variation in effect sizes and predicted values among studies of similar phenomena is inevitable, such variation far exceeds what might be produced by sampling error alone. One possible explanation for variation among results is differences among researchers in the decisions they make regarding statistical analyses. A growing array of studies has explored this analytical variability in different fields and has found substantial variability among results despite analysts having the same data and research question. Many of these studies have been in the social sciences, but one small “many analyst” study found similar variability in ecology. We expanded the scope of this prior work by implementing a large-scale empirical exploration of the variation in effect sizes and model predictions generated by the analytical decisions of different researchers in ecology and evolutionary biology. We used two unpublished datasets, one from evolutionary ecology (blue tit, Cyanistes caeruleus , to compare sibling number and nestling growth) and one from conservation ecology ( Eucalyptus , to compare grass cover and tree seedling recruitment). The project leaders recruited 174 analyst teams, comprising 246 analysts, to investigate the answers to prespecified research questions. Analyses conducted by these teams yielded 141 usable effects (compatible with our meta-analyses and with all necessary information provided) for the blue tit dataset, and 85 usable effects for the Eucalyptus dataset. We found substantial heterogeneity among results for both datasets, although the patterns of variation differed between them. For the blue tit analyses, the average effect was convincingly negative, with less growth for nestlings living with more siblings, but there was near continuous variation in effect size from large negative effects to effects near zero, and even effects crossing the traditional threshold of statistical significance in the opposite direction. In contrast, the average relationship between grass cover and Eucalyptus seedling number was only slightly negative and not convincingly different from zero, and most effects ranged from weakly negative to weakly positive, with about a third of effects crossing the traditional threshold of significance in one direction or the other. However, there were also several striking outliers in the Eucalyptus dataset, with effects far from zero. For both datasets, we found substantial variation in the variable selection and random effects structures among analyses, as well as in the ratings of the analytical methods by peer reviewers, but we found no strong relationship between any of these and deviation from the meta-analytic mean. In other words, analyses with results that were far from the mean were no more or less likely to have dissimilar variable sets, use random effects in their models, or receive poor peer reviews than those analyses that found results that were close to the mean. The existence of substantial variability among analysis outcomes raises important questions about how ecologists and evolutionary biologists should interpret published results, and how they should conduct analyses in the future.
Automatic classification of submerged macrophytes at Lake Constance using laser bathymetry point clouds
(2024) Wagner, Nike; Franke, Gunnar; Schmieder, Klaus; Mandlburger, Gottfried; Stateczny, Andrzej
Submerged aquatic vegetation, also referred to as submerged macrophytes, provides important habitats and serves as a significant ecological indicator for assessing the condition of water bodies and for gaining insights into the impacts of climate change. In this study, we introduce a novel approach for the classification of submerged vegetation captured with bathymetric LiDAR (Light Detection And Ranging) as a basis for monitoring their state and change, and we validated the results against established monitoring techniques. Employing full-waveform airborne laser scanning, which is routinely used for topographic mapping and forestry applications on dry land, we extended its application to the detection of underwater vegetation in Lake Constance. The primary focus of this research lies in the automatic classification of bathymetric 3D LiDAR point clouds using a decision-based approach, distinguishing the three vegetation classes, (i) Low Vegetation, (ii) High Vegetation, and (iii) Vegetation Canopy, based on their height and other properties like local point density. The results reveal detailed 3D representations of submerged vegetation, enabling the identification of vegetation structures and the inference of vegetation types with reference to pre-existing knowledge. While the results within the training areas demonstrate high precision and alignment with the comparison data, the findings in independent test areas exhibit certain deficiencies that are likely addressable through corrective measures in the future.
Seed dispersal by wind decreases when plants are water‐stressed, potentially counteracting species coexistence and niche evolution
(2021) Zhu, Jinlei; Lukić, Nataša; Rajtschan, Verena; Walter, Julia; Schurr, Frank M.
Hydrology is a major environmental factor determining plant fitness, and hydrological niche segregation (HNS) has been widely used to explain species coexistence. Nevertheless, the distribution of plant species along hydrological gradients does not only depend on their hydrological niches but also depend on their seed dispersal, with dispersal either weakening or reinforcing the effects of HNS on coexistence. However, it is poorly understood how seed dispersal responds to hydrological conditions. To close this gap, we conducted a common‐garden experiment exposing five wind‐dispersed plant species (Bellis perennis, Chenopodium album, Crepis sancta, Hypochaeris glabra, and Hypochaeris radicata) to different hydrological conditions. We quantified the effects of hydrological conditions on seed production and dispersal traits, and simulated seed dispersal distances with a mechanistic dispersal model. We found species‐specific responses of seed production, seed dispersal traits, and predicted dispersal distances to hydrological conditions. Despite these species‐specific responses, there was a general positive relationship between seed production and dispersal distance: Plants growing in favorable hydrological conditions not only produce more seeds but also disperse them over longer distances. This arises mostly because plants growing in favorable environments grow taller and thus disperse their seeds over longer distances. We postulate that the positive relationship between seed production and dispersal may reduce the concentration of each species to the environments favorable for it, thus counteracting species coexistence. Moreover, the resulting asymmetrical gene flow from favorable to stressful habitats may slow down the microevolution of hydrological niches, causing evolutionary niche conservatism. Accounting for context‐dependent seed dispersal should thus improve ecological and evolutionary models for the spatial dynamics of plant populations and communities.
Quantifying patch‐specific seed dispersal and local population dynamics to estimate population spread of an endangered plant species
(2021) Zhu, Jinlei; Hrušková, Karolína; Pánková, Hana; Münzbergová, Zuzana
Aim: Habitat loss and fragmentation impose high extinction risk upon endangered plant species globally. For many endangered plant species, as the remnant habitats become smaller and more fragmented, it is vital to estimate the population spread rate of small patches in order to effectively manage and preserve them for potential future range expansion. However, population spread rate has rarely been quantified at the patch level to inform conservation strategies and management decisions. To close this gap, we quantify the patch-specific seed dispersal and local population dynamics of Minuartia smejkalii, which is a critically endangered plant species endemic in the Czech Republic and is of urgent conservation concern. Location: Želivka and Hrnčíře, Czechia. Methods: We conducted demographic analyses using population projection matrices with long-term demographic data and used an analytic mechanistic dispersal model to simulate seed dispersal. We then used information on local population dynamics and seed dispersal to estimate the population spread rate and compared the relative contributions of seed dispersal and population growth rate to the population spread rate. Results: We found that although both seed dispersal and population growth rate in M. smejkalii were critically limited, the population spread rate depended more strongly on the maximal dispersal distance than on the population growth rate. Main conclusions: We recommend conservationists to largely increase the dispersal distance of M. smejkalii. Generally, efforts made to increase seed dispersal ability could largely raise efficiency and effectiveness of conservation actions for critically endangered plant species.
Cd and Zn concentrations in soil and silage maize following the addition of P fertilizer
(2021) Niño-Savala, Andrea Giovanna; Weishaar, Benedikt; Franzaring, Jürgen; Liu, Xuejun; Fangmeier, Andreas
Studies of soil Cd and Zn are often performed on sites that are contaminated or have deficient Zn conditions. Soil characteristics and crop management could impact the soil mobility and uptake of Cd and Zn, even when considering unpolluted Cd soils and adequate soil Zn levels. The concentrations of these two metals were assessed in soil and silage maize under five P fertilization treatments at two growth stages under low Cd and sufficient Zn conditions. Pearson correlation coefficients and stepwise linear regressions were calculated to investigate the soil characteristics influencing the bioavailable metal fraction in soil and the metal concentration in silage maize. P treatments did not impact Cd accumulation in maize; however, the Zn uptake was affected by P placement at the leaf development stage. From early development to maturity, the Cd level in maize decreased to 10% of the initial uptake, while the Zn level decreased to 50% of the initial uptake. This reduction in both metals may be attributed to a dilution effect derived from high biomass production. Silage maize could alleviate the initial Cd uptake while diminishing the depressant effect of P fertilizer on Zn concentration. Further research is required to understand the effect of P fertilizer on Cd uptake and its relation to Zn under field conditions at early and mature stages.
Effects of land-use intensity on functional community composition and nutrient dynamics in grassland
(2024) Walter, Julia; Thumm, Ulrich; Buchmann, Carsten M.; Heinonen-Tanski, Helvi
Land-use intensity drives productivity and ecosystem functions in grassland. The effects of long-term land-use intensification on plant functional community composition and its direct and indirect linkages to processes of nutrient cycling are largely unknown. We manipulated mowing frequency and nitrogen inputs in an experiment in temperate grassland over ten years. We assessed changes in species composition and calculated functional diversity (FDis) and community weighted mean (CWM) traits of specific leaf area (SLA), leaf dry matter content (LDMC) and leaf and root nitrogen of the plant community, using species-specific trait values derived from databases. We assessed above- and belowground decomposition and soil respiration. Plant diversity strongly decreased with increasing land-use intensity. CWM leaf nitrogen and SLA decreased, while CWM LDMC increased with land-use intensification, which could be linked to an increased proportion of graminoid species. Belowground processes were largely unaffected by land-use intensity. Land use affected aboveground litter composition directly and indirectly via community composition. Mowing frequency, and not a land-use index combining mowing frequency and fertilization, explained most of the variation in litter decomposition. Our results show that land-use intensification not only reduces plant diversity, but that these changes also affect nutrient dynamics.
Simulating the spread and establishment of alien species along aquatic and terrestrial transport networks: A multi‐pathway and high‐resolution approach
(2022) Bagnara, Maurizio; Nowak, Larissa; Boehmer, Hans Juergen; Schöll, Franz; Schurr, Frank M.; Seebens, Hanno
The introduction and further spread of many alien species have been a result of trade and transport. Consequently, alien species are often found close to traffic infrastructure and urban areas. To contain and manage the spread of alien species, it is essential to identify and predict major routes of spread, which cannot be obtained by applying common modelling approaches such as species distribution models. Here, we present a new model called CASPIAN to simulate the dispersal of alien species along traffic infrastructure and the establishment of populations along these routes. The model simulates simultaneous spread of species of up to eight different modes of transport along roads, railways and waterways. We calibrated and validated the model using two species that spread within Germany as case studies: the terrestrial plant Senecio inaequidens and the freshwater clam Corbicula fluminea, and performed a shortest path analysis to quantify the relative importance of individual routes for spread. The application of the model yielded detailed predictions of dispersal and establishment for >600,000 segments of the traffic network throughout Germany. Once calibrated, the model captured the general spread dynamics of the two species with higher accuracy for the freshwater environment due to the higher quality of data available for the aquatic species. The quantification of spread routes using the shortest path analysis revealed a clear backbone of major routes of spread, which varied depending on the type of traffic network and the starting points considered. Major routes of spread aligned with high traffic intensities, but high traffic per se did not necessarily result in high spread intensities. Synthesis and application. By simulating the spreading dynamics of alien species along transport networks across multiple pathways, CASPIAN enables the identification of major spread routes along different dispersal pathways and quantification of their relative importance, which helps prioritising pathways of introduction as required by international biodiversity goals such as the CBD Aichi targets.
Improving measurements of the falling trajectory and terminal velocity of wind‐dispersed seeds
(2022) Zhu, Jinlei; Buchmann, Carsten M.; Schurr, Frank M.
Seed dispersal by wind is one of the most important dispersal mechanisms in plants. The key seed trait affecting seed dispersal by wind is the effective terminal velocity (hereafter “terminal velocity”, Vt), the maximum falling speed of a seed in still air. Accurate estimates of Vt are crucial for predicting intra‐ and interspecific variation in seed dispersal ability. However, existing methods produce biased estimates of Vt for slow‐ or fast‐falling seeds, fragile seeds, and seeds with complex falling trajectories. We present a new video‐based method that estimates the falling trajectory and Vt of wind‐dispersed seeds. The design involves a mirror that enables a camera to simultaneously record a falling seed from two perspectives. Automated image analysis then determines three‐dimensional seed trajectories at high temporal resolution. To these trajectories, we fit a physical model of free fall with air resistance to estimate Vt. We validated this method by comparing the estimated Vt of spheres of different diameters and materials to theoretical expectations and by comparing the estimated Vt of seeds to measurements in a vertical wind tunnel. Vt estimates closely match theoretical expectations for spheres and vertical wind tunnel measurements for seeds. However, our Vt estimates for fast‐falling seeds are markedly higher than those in an existing trait database. This discrepancy seems to arise because previous estimates inadequately accounted for seed acceleration. The presented method yields accurate, efficient, and affordable estimates of the three‐dimensional falling trajectory and terminal velocity for a wide range of seed types. The method should thus advance the understanding and prediction of wind‐driven seed dispersal.
Floral visitation to alien plants is non‐linearly related to their phylogenetic and floral similarity to native plants
(2022) Razanajatovo, Mialy; Rakoto Joseph, Felana; Rajaonarivelo Andrianina, Princy; van Kleunen, Mark
Biological invasions are key to understanding ecological processes that determine the formation of novel interactions. Alien species can negatively impact floral visitation to native species, but native species may also facilitate early establishment of closely related alien species by providing a preadapted pollinator community. We tested whether floral visitation to alien species depended on phylogenetic relatedness and floral similarity to native species. In a field experiment, we simulated the early stages of an invasion by adding potted alien plants into co‐flowering native communities. We paired each alien plant with a host native plant, and recorded floral visitation to them for 3,068 hr (totalling 84,814 visits). We used 34 alien and 20 native species in 151 species combinations. We tested whether the number of floral visits to alien plants, the proportion of visits to alien plant relative to visits to both alien and native plants, and the similarity in flower visitor compositions of alien and native plants depended on phylogenetic and floral trait distances between alien and native species. Floral visitation to alien species was highest when they had intermediate floral trait distances to native species, and either low or high phylogenetic distances. Alien species received more similar flower‐visitor groups to natives when they had low phylogenetic and either low or high floral trait distances to native species. Co‐flowering native species may facilitate floral visitation to closely related alien species, and distantly related alien plants seem to avoid competition for flower visitors with native plants. Alien species with similar floral traits to natives compete with them for flower visitors, and alien species with dissimilar floral traits may not share flower visitors with native species. Alien species with intermediate floral trait distances to natives are most likely to receive flower visitors, as they are not too dissimilar and may still share flower visitors with native species, but not too similar to compete for flower visitors with them. The non‐linear patterns between floral visitation and similarity of the alien and native species suggest that an interplay of facilitation and competition simultaneously drives the formation of novel plant‐pollinator interactions.
Effect of rhizome severing on survival and growth of rhizomatous herb Phragmites communis is regulated by sand burial depth
(2022) Zhai, Shanshan; Qian, Jianqiang; Ma, Qun; Liu, Zhimin; Ba, Chaoqun; Xin, Zhiming; Tian, Liang; Zong, Lu; Liang, Wei; Zhu, Jinlei
Rhizome fragmentation and sand burial are common phenomena in rhizomatous clonal plants. These traits serve as an adaptive strategy for survival in stressful environments. Thus far, some studies have been carried out on the effects of rhizome fragmentation and sand burial, but how the interaction between rhizome fragmentation and sand burial affects the growth and reproduction of rhizomatous clonal plants is unclear. We investigated the effect of the burial depth and rhizome fragment size on the survival and growth of the rhizomatous herb Phragmites communis using 288 clonal fragments (6 burial depths × 8 clonal fragment sizes × 6 replicates) in a field rhizome severing experiment. The ramet survival of the rhizomatous species significantly increased with the sand burial depth and clonal fragment size (p < 0.01), and the effects of the clonal fragment size on ramet survival depended on the sand burial depth. Sand burial enhanced both the vertical and horizontal biomass (p < 0.05), while the clonal fragment size affected the vertical biomass rather than the horizontal biomass. Sand burial facilitated the vertical growth of ramets (p < 0.05) while the number of newly produced ramets firstly increased and then decreased with the increasing clonal fragment size, and the maximal value appeared in four clonal fragments under a heavy sand burial depth. There is an interaction between the burial depth and rhizome fragment size in the growth of rhizome herbaceous plants. The population growth increases in the increase of sand burial depth, and reaches the maximum under severe sand burial and moderate rhizome fragmentation.
Agrivoltaics: The environmental impacts of combining food crop cultivation and solar energy generation
(2023) Wagner, Moritz; Lask, Jan; Kiesel, Andreas; Lewandowski, Iris; Weselek, Axel; Högy, Petra; Trommsdorff, Max; Schnaiker, Marc-André; Bauerle, Andrea
The demand for food and renewable energy is increasing significantly, whereas the availability of land for agricultural use is declining. Agrivoltaic systems (AVS), which combine agricultural production with solar energy generation on the same area, are a promising opportunity with the potential to satisfy this demand while avoiding land-use conflicts. In the current study, a Consequential Life-Cycle Assessment (CLCA) was conducted to holistically assess the environmental consequences arising from a shift from single-use agriculture to AVS in Germany. The results of the study show that the environmental consequences of the installation of overhead AVS on agricultural land are positive and reduce the impacts in 15 of the 16 analysed impact categories especially for climate change, eutrophication and fossil resource use, as well as in the single score assessment, mainly due to the substitution of the marginal energy mix. It was demonstrated that, under certain conditions, AVS can contribute to the extension of renewable energy production resources without reducing food production resources. These include maintaining the agricultural yields underneath the photovoltaic (PV) modules, seeking synergies between solar energy generation and crop production and minimising the loss of good agricultural land.
Editorial: Seed behavior in response to extreme environments
(2023) Zhu, Jinlei; Wang, Lei
The importance of individual movement and feeding behaviour for long-distance seed dispersal by red deer: a data-driven model
(2020) Wright, Stephen J.; Heurich, Marco; Buchmann, Carsten M.; Böcker, Reinhard; Schurr, Frank M.
Background: Long-distance seed dispersal (LDD) has strong impacts on the spatiotemporal dynamics of plants. Large animals are important LDD vectors because they regularly transport seeds of many plant species over long distances. While there is now ample evidence that behaviour varies considerably between individual animals, it is not clear to what extent inter-individual variation in behaviour alters seed dispersal by animals. Methods: We study how inter-individual variation in the movement and feeding behaviour of one of Europe’s largest herbivores (the red deer, Cervus elaphus) affects internal seed dispersal (endozoochory) of multiple plant species. We combine movement data of 21 individual deer with measurements of seed loads in the dung of the same individuals and with data on gut passage time. These data serve to parameterize a model of passive dispersal that predicts LDD in three orientations (horizontal as well as upward and downward in elevation). With this model we investigate to what extent per-seed probabilities of LDD and seed load vary between individuals and throughout the vegetation period (May–December). Subsequently, we test whether per-seed LDD probability and seed load are positively (or negatively) correlated so that more mobile animals disperse more (or less) seeds. Finally, we examine whether non-random associations between per-seed LDD probability and seed load affect the LDD of individual plant species. Results: The studied deer dispersed viable seeds of at least 62 plant species. Deer individuals varied significantly in per-seed LDD probability and seed loads. However, more mobile animals did not disperse more or less seeds than less mobile ones. Plant species also did not differ significantly in the relationship between per-seed LDD probability and seed load. Yet plant species differed in how their seed load was distributed across deer individuals and in time, and this caused their LDD potential to differ more than twofold. For several plant species, we detected non-random associations between per-seed LDD probability and seed load that generally increased LDD potential. Conclusions: Inter-individual variation in movement and feeding behaviour means that certain deer are substantially more effective LDD vectors than others. This inter-individual variation reduces the reliability of LDD and increases the sensitivity of LDD to the decline of deer populations. Variation in the dispersal services of individual animals should thus be taken into account in models in order to improve LDD projections.
Native and alien species suffer from late arrival, while negative effects of multiple alien species on natives vary
(2021) Ferenc, Viktoria; Merkert, Christian; Zilles, Frederik; Sheppard, Christine S.
Ongoing globalisation and climate change are causing plant species to invade new habitats and thereby alter biodiversity and ecosystem functioning. Since numbers of plant invasions continue to increase globally, it is crucial to investigate the effects of multiple co-occurring alien species on native communities. Furthermore, priority effects due to the earlier emergence of certain species affecting fitness of later arriving species can shape community structure and affect native species performance. We investigate in a common garden pot experiment the interactions among five alien-native species pairs. First we focus on the effect of growing with either one or two alien neighbour species on a native plant, second we alter the arrival time of the alien or native neighbour by 3 weeks. Generally, native species performance decreased when surrounded by two alien species compared to only one, although the magnitude of this effect varied depending on species, with one species even performing better with alien neighbours than in monoculture. Species performance greatly decreased when arriving second in the pot, for both native and alien species. In contrast, alien species tended to benefit more from arriving early. Given that we studied annual ruderal species, their potentially lower competitive ability might explain why we detected negative effects of late arrival. We highlight the need to further elucidate underlying mechanisms of small-scale invasion dynamics to achieve generalisations concerning the response of multiple alien and native plants given their species-specific differences in response to neighbour species and arrival time.
Agrivoltaic system impacts on microclimate and yield of different crops within an organic crop rotation in a temperate climate
(2021) Weselek, Axel; Bauerle, Andrea; Hartung, Jens; Zikeli, Sabine; Lewandowski, Iris; Högy, Petra
Agrivoltaic (AV) systems integrate the production of agricultural crops and electric power on the same land area through the installation of solar panels several meters above the soil surface. It has been demonstrated that AV can increase land productivity and contribute to the expansion of renewable energy production. Its utilization is expected to affect crop production by altering microclimatic conditions but has so far hardly been investigated. The present study aimed to determine for the first time how changes in microclimatic conditions through AV affect selected agricultural crops within an organic crop rotation. For this purpose, an AV research plant was installed near Lake Constance in south-west Germany in 2016. A field experiment was established with four crops (celeriac, winter wheat, potato and grass-clover) cultivated both underneath the AV system and on an adjacent reference site without solar panels. Microclimatic parameters, crop development and harvestable yields were monitored in 2017 and 2018. Overall, an alteration in microclimatic conditions and crop production under AV was confirmed. Photosynthetic active radiation was on average reduced by about 30% under AV. During summertime, soil temperature was decreased under AV in both years. Furthermore, reduced soil moisture and air temperatures as well as an altered rain distribution have been found under AV. In both years, plant height of all crops was increased under AV. In 2017 and 2018, yield ranges of the crops cultivated under AV compared to the reference site were −19 to +3% for winter wheat, −20 to +11% for potato and −8 to −5% for grass-clover. In the hot, dry summer 2018, crop yields of winter wheat and potato were increased by AV by 2.7% and 11%, respectively. These findings show that yield reductions under AV are likely, but under hot and dry weather conditions, growing conditions can become favorable.

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