BG3.20

Since modern days, anthropogenic activity significantly alters the nitrogen and phosphorus cycle, and these changes are substantially affecting terrestrial plant communities. Along with potassium (K), nitrogen (N) and phosphorus (P) are key nutrients limiting plant growth. Plants occupy distinct niches along N:P ratio gradients, and their physiological adaptation to these environments could potentially help us understand current and future species composition within N- and P-limited soils. Bergmann et al. (2020), provided an improved two-dimensional conceptual framework to understand resource acquisition through belowground rooting behaviour. They discerned two largely independent gradients: a conservation and a collaboration gradient. The conservation gradient differentiates between species with a slow strategy, which have a high root tissue density implying slow resource uptake and investment in long-living roots, and species with a fast strategy, that show high root N concentration implying high resource uptake but a short lifespan. The collaboration gradient goes from an outsourcing strategy with a high root diameter allowing carbon investment in fungal partners versus a do-it-yourself soil exploration strategy which requires a high specific root length. This framework, however, has not been assessed from a nutrient stoichiometric perspective. For this, we retrieved 12 belowground traits from trait databases and linked them to a European-wide field dataset of 990 vegetation recordings with species composition, site-productivity and nutrient contents of herbaceous ecosystems (extended dataset building on Wassen et al. (2021)). Using the framework of Bergmann et al. (2020), we show that plant communities in P-limited sites have adopted a slow and collaborative belowground strategy, whereas N-limited plant communities show a fast and do-it-yourself belowground strategy. Our result implies that, in addition to the benefit for fast-growing species in a nutrient-enriching world, anthropogenic alterations in the nutrient balance may also heavily affect species fitness and survival due to their nutrient-specific rooting strategies. The biggest remaining question is, however, if species will be able to adapt to changes in nutrient stoichiometry and if they can, how fast this adaptation process will be. Our results provide a new insight into belowground strategies under N or P limitation and may have consequences for the representation of plant traits in vegetation models. Finally, we strongly urge to analyse rooting traits of a larger number of species along a N:P gradient to increase the reliability of community trait estimates.

References:

Bergmann, J., Weigelt, A., van der Plas, F., Laughlin, D. C., Kuyper, T. W., Guerrero-Ramirez, N., Valverde-Barrantes, O. J., Bruelheide, H., Freschet, G. T., Iversen, C. M., Kattge, J., McCormack, M. L., Meier, I. C., Rillig, M. C., Roumet, C., Semchenko, M., Sweeney, C. J., van Ruijven, J., York, L. M., & Mommer, L. (2020). The fungal collaboration gradient dominates the root economics space in plants. Science Advances, 6(27), eaba3756. https://doi.org/10.1126/sciadv.aba3756

Wassen, M. J., Schrader, J., van Dijk, J., & Eppinga, M. B. (2021). Phosphorus fertilization is eradicating the niche of northern Eurasia’s threatened plant species. Nature Ecology & Evolution, 5(1), 67-73. https://doi.org/10.1038/s41559-020-01323-w

How to cite: Scheifes, D. and Wassen, M.: Plant nutrient acquisition strategies along an N:P gradient: implications for vegetation models, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7397, https://doi.org/10.5194/egusphere-egu21-7397, 2021.

Andean ecosystems exhibit a natural limitation in nutrients such as Phosphorus that, potentially, affect the entire ecosystem´s metabolism, function and resilience to environmental perturbation. Due to this limitation in the soil, atmospheric inputs via wet or dry deposition become a determinant source of nutrients to the ecosystems. In highly disturbed Andean forests, scattered trees that remain in the landscape after forest conversion into other land uses, have been designated as key structures due to the ecological functions they have relative to the area they occupy, allowing to improve the biophysical and biogeochemical conditions of the place. On a Landscape-scale, they modify spatial heterogeneity, and contribute ecological connectivity that helps plant species dispersal. Previous studies have demonstrated the importance of precipitation for nutrient inputs into forests where various tree species differ in their responses because of their specificity, trait configuration, and changes in plant community competitive hierarchies. However, few studies have quantified the response of functional traits for different species of trees, evaluating their ability to intercept and move phosphorus through the relationship with hydrological processes. We determined the interception and input of phosphorus into the ecosystem through the study of twenty individuals from five scattered tree species in a modified Andean landscape: Croton magdalenensis, Tibouchina lepidota, Vismia Baccifera, and Quercus humboldtii, which are dominant and native to the Northern Andes, as well as a common exotic species in the area Eucaliptus globulus, generally planted for timber. In all individuals, we measured functional traits that relate, and potentially explain rainfall interception, and quantified concentrations of phosphate PO4 in precipitation, throughfall, and stemflow in all individual trees for a group of 16 individual rain events that varied in their hydrological characteristics. In general, PO4 concentrations in precipitation were low, although variation associated with hydrological characteristics of precipitation (intensity, duration, magnitude and cumulative precipitation in the previous days) was generally observed. In most cases were concentrations of PO4 were observed in precipitation, throughfall and stemflow had similar concentrations in most trees, highlighting the potential role of these hydrological processes in redistributing nutrients into the root zone.  Notably, one particular species, Croton magdalenensis, a pioneer species that generally dominates early forest recovery in disturbed areas, had significantly higher values of PO4 concentration in throughflow and stemflow compared to concentration in oncoming precipitation, as well as in the same fluxes on the other species. This condition potentially results from a particularly higher epiphyte load in these trees, which potentially facilitate biogeochemical exchange and enhances ecological functions associated with early stages of forest recovery.  Overall, our results highlight the complex biogeochemical interactions that occur in these highly biodiverse ecosystems where plant functional traits can be useful to describe ecosystem function at the landscape scale.  More generally, our results can be useful for restoration processes where ecosystem function, and particularly biogeochemical processes related to limiting nutrients (such as Phosphorous), need to be prioritized.

Keywords: precipitation, phosphorus interception, nutrients limitation, scattered tree, functional traits.

How to cite: Vásquez, S. and Villegas, J. C.: Redistribution of Phosphate into the soil via hydrological processes explained by functional traits in scattered trees of different species in the tropical Andes., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7714, https://doi.org/10.5194/egusphere-egu21-7714, 2021.

Fine root biomass (FRB) is a small but important forest ecosystem pool due to its direct role in ecosystem functioning through belowground carbon and soil nutrient cycling. At the global scale there is evidence that FRB correlates with meteorological parameters, e.g. precipitation and air temperature. Moving from global to regional and local scales other environmental parameters, primarily related to site soil characteristics, become more important.
In this research, we investigated which soil parameters are important as drivers of fine root biomass in three different biogeographical regions in Croatia, namely the Continental, the Alpine and the Mediterranean.  We collected data on soil and site characteristics at 242 locations. Soil parameters include bulk density, texture, pH and C, N and P content, while site parameters were latitude, longitude, elevation, precipitation, air temperature and forest type (Coniferous, Broadleaves, and Maquis/Garigues). Fine root biomass was estimated from soil samples collected at 2-8 positions at each location. Soil was sampled down to 30 cm depth in the mineral layer with a split-tube sampler, and analysed for three depths, i.e. 0-10 cm, 10-20 cm, and 20-30 cm depth.
Across entire dataset, FRB was affected by precipitation, elevation, forest type, soil depth, and soil C/P and N/P relations. Moving down to each biogeographical region separately, a stronger effect of soil phosphorus was observed for the Mediterranean region.

How to cite: Ostrogović Sever, M. Z., Dimoski, D., Anić, M., and Marjanović, H.: Forest fine root biomass and soil CNP stoichiometry across three different biogeographical regions in Croatia, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13723, https://doi.org/10.5194/egusphere-egu21-13723, 2021.

Increasing atmospheric CO₂ concentrations can be a driver for higher ecosystem productivity across the globe but nutrient availability may limit subsequent biomass growth. Concurrently, increased anthropogenic nitrogen (N) deposition introduces a relatively large amount of N into the system, thus potentially alleviating N limitation. However, this new N input could push ecosystems into being limited by other resources, most importantly phosphorus (P) in mid- and high-latitude systems, leading to what has been termed an NP imbalance. While the ecological theory behind the processes described above has been discussed on many occasions, it is yet unclear what the actual spatial and temporal patterns of such an imbalance are, as well as the ecpological processes and drivers behind such observed patterns.

Here, we use leaf N and P data from a large European monitoring network, ICP forests, in conjunction with a land surface model, QUINCY (QUantifying Interactions between terrestrial Nutrient CYcles and the climate system), to explore the patterns and drivers behind nutrient limitation at European forest sites. The overall trend in observed leaf N and P content as well as N:P ratio show an increasing nutrient limitation from 1990 to 2015, as well as a shift towards P limitation. However, the observed spatial patterns of change in leaf nutrient content vary strongly with soil nutrient availability, N deposition and leaf habit. The effect of leaf habit suggests that leaf growth strategies  play an important role in dealing with nutrient availability and controlling observed ecosystem responses. 

We use the QUINCY model to explore the drivers behind the observed leaf nutrient trends. We perform simulations with fixed levels of atmospheric CO₂ as well as in the absence of anthropogenic nitrogen deposition. We show that the decrease in leaf N and P content is attributable to increased atmospheric CO_2, while the changes in N:P stoichiometry are reproducible with increased N deposition. Additionally, the model can only predict observed trends when representing physiologically-realistic responses of leaf stoichiometry to nutrient availability. The use of a process-based model allows us to attribute drivers to the observed changes in leaf nutrient content. This research helps the development of data-constrained, process-based models which can potentially be used to predict changes in ecosystem nutrient limitation, and implicitly growth and carbon storage, under future scenarios

How to cite: Caldararu, S., Fleischer, K., Yu, L., and Zaehle, S.: Changes in leaf nitrogen and phosphorus content from observations and a land surface model: evidence for increasing nutrient imbalance in Europe, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2912, https://doi.org/10.5194/egusphere-egu21-2912, 2021.

Foliar properties play a crucial role in local and global biochemical cycles. Systematic variation in key leaf traits has been reported both between and within species. Intraspecific variation in leaf traits is controlled by micro-environmental conditions and follows seasonal patterns. In this study we examine the seasonal patterns of six foliar traits including leaf area (LA), leaf thickness (Lth), leaf mass per area (LMA), leaf dry matter content (LDMC), leaf area to sapwood area ratio (LA/SA) and branch wood density (WD) in addition to the associated parameters of the Michaelis-Menten light response curve (i.e. light saturated net photosynthetic rate (Asat), half saturation coefficient (Km) and dark respiration rate (Rd)). We measured on a monthly basis the foliar traits and developed light response curves in four Pinus brutia dominated stands along a post-fire chronosequence (15, 40, 70 and 90 years) from sunlit branches. Significant differences in the interannual trait variability were found between stands for LDMC, WD and Asat, with the highest variability identified in the younger plot. LA/SA, Rd and Km also showed strong interannual variability although not statistically different between plots. A mixed effect model analysis revealed high intraclass correlation coefficients for Km and Asat suggesting that net photosynthesis is following systematic seasonal patterns. Overall LA was higher and LDMC was lower in the oldest plot and WD was higher in the denser (40 years) plot. Interestingly gas exchange parameters did not show differences in their overall mean values. Across plots, Asat was strongly positively related to Km, and LMA was positively related to LDMC and Lth. LDMC was also positively related with Asat and negatively with Lth. A principal component analysis (PCA) revealed two major dimensions of intraspecific trait variability within our plots. The first PCA axis was positively related to Asat, Km, LDMC and LMA suggesting that regardless of the stand age needles are placed along a fast-slow carbon gain dimension with denser needles illustrating faster area-based photosynthesis. The second PCA axis was positively related to LA and Lth suggesting that bigger needles are also thicker. A subsequent permutational multivariate analysis of variance revealed that the centroids and the dispersion of the trait syndromes differed between stands, with the youngest plot illustrating higher trait dispersion and the oldest plot characterized by bigger and thicker needles. Thus, in older stands were competition for light is higher, needles are deployed to be bigger and thicker to optimize light capture, while in younger stands they are optimized along a leaf density - photosynthetic capacity spectrum depending on (more heterogeneous) microenvironmental conditions. Our findings illustrate that intraspecific variation can be attributed to either seasonal (abiotic) light availability or to (biotic) heterogeneity related to stand structure, and have important implications for local scale forest dynamics models.

«This research is co-financed by Greece and the European Union (European Social Fund- ESF) through the Operational Programme «Human Resources Development, Education and Lifelong Learning 2014-2020» in the context of the project “Carbon fluxes across a post-fire chronosequence in Pinus brutia Ten forests.” (MIS 5049513)».

How to cite: Sazeides, C. I., Fyllas, N. M., and Christopoulou, A.: Seasonal variation in foliar properties in Mediterranean Pine forests of different post-fire age, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1064, https://doi.org/10.5194/egusphere-egu21-1064, 2021.

The timings of phenological events play an important role in determining the annual carbon uptake in key terrestrial carbon sinks, such as mature forests. With increases in atmospheric CO₂ expected to change physiological processes in plants, it is becoming increasingly important to monitor the changes in plant traits and subsequent phenological changes that may occur. Changes in photosynthetic pigments, such as chlorophyll, can be used as a proxy for physiological changes in leaves and can therefore be useful to monitor potential phenological change, such as autumnal leaf senescence. Non-destructive techniques allow for measurements of photosynthetic pigments without destructive sampling that would disturb the canopy. These methods are particularly useful in logistically difficult environments, such as high forest, or remote environments where traditional chlorophyll extractions are problematic and serve as ground-truthing for remote sensing of greenness. In the present study, we aimed to assess the effects of elevated CO₂ (150 mmol mol^-1 above ambient) and canopy position on chlorophyll concentrations of a common canopy-dominant species to identify potential implications on phenology. The study was conducted in a mature temperate forest situated at a Free Air Carbon Enrichment (FACE) experiment in the UK. Over 5,000 in-situ chlorophyll measurements were collected, across the 3^rd and 4^th season of CO₂ fumigation, in the canopy-dominant species Quercus robur (Q. robur). Additionally, 100 leaves were destructively sampled to verify chlorophyll concentrations using traditional chlorophyll extraction techniques. The established relationship between chlorophyll absorptance readings and leaf chlorophyll content allowed robust species-specific calibration equations to be calculated. Consistent with previous work, this study observed significantly higher chlorophyll concentrations at lower positions in the canopy in both sampling years (P < 0.001). Additionally, a reduction in foliar chlorophyll concentrations (-2 to -9%) when exposed to eCO₂ in both sampling years was observed, but this was only significant for the upper canopy (-7 to -9%, P < 0.05). This study found a marginally significant effect of CO₂ treatment on reducing the effective season length, with larger eCO₂-induced reductions in chlorophyll occurred through autumn. Overall, the research highlights a simple non-invasive method for monitoring changes in leaf traits of mature trees under eCO₂. The results suggest that leaves may be able to reallocate their resources away from light-harvesting apparatus in response to eCO₂, particularly in the upper canopy. Furthermore, the findings suggest direct consequences of rising atmospheric CO₂ to potential alterations of phenological events, such as leaf senescence, that may have implications for forest productivity and adaptation in a future high CO₂ world. Additionally, the research has shown the need to monitor potential changes in resource allocation to photosynthetic apparatus across the season as atmospheric CO₂ continues to rise. The information obtained in this study can be used to increase accuracy in the modelling of climate-carbon scenarios.

How to cite: Gardner, A., Ellsworth, D., Pritchard, J., and Mackenzie, R.: The effects of elevated CO2 and canopy position on chlorophyll concentration in mature Quercus robur., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9410, https://doi.org/10.5194/egusphere-egu21-9410, 2021.

Plant functional traits have great influence in how terrestrial ecosystems function. This key information is however generally oversimplified in most Earth system models (ESMs) and is typically represented by a number of static, empirically fixed values assigned to a selection of plant functional types (PFTs). This leads to reducing the diversity of plant communities into a relatively low number of categories and key variability within individual PFTs is lost. Subgrid processes are thus underrepresented and accuracy compromised.

The TRY global traits database contains the largest set of in-situ trait observations for numerous species around the globe. Despite the large number of species and samples included in trait databases, such as TRY, they are sparse compared to the overall richness and diversity of species globally. We propose the use of the massive geolocated plant occurrence data from the Global Biodiversity Information Facility (GBIF) as ancillary source of information to better capture species distributions, especially in locations where TRY data are missing. 

As a first order approach, GBIF was used to estimate species abundances for a given study area (contiguous United States), and they were further corrected with high resolution, subpixel maps of PFT derived via remote sensing and machine learning upscaling.  This information was used to provide ecosystem level trait estimates for a selection of plant traits (specific leaf area and leaf nitrogen concentration). The proposed approach allows us to link local biodiversity composition from GBIF with a more precise and realistic representation of plant community composition coming from remote sensing information for ecosystem-level trait estimation. Among many possible applications of these data, the addition of the produced trait estimates to improve ESMs estimations could be very valuable to improve the understanding and monitoring of the biosphere.

How to cite: Moreno-Martínez, Á., Adsuara, J. E., Muñoz-Marí, J., Izquierdo-Verdiguier, E., Katge, J., Carvalhais, N., Reichstein, M., Running, S. W., and Camps-Valls, G.: Upscaling plant traits to ecosystem level: blending local biodiversity,  global traits databases, and remote sensing data., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15835, https://doi.org/10.5194/egusphere-egu21-15835, 2021.

To understand the interaction between vegetation and the climate, Dynamic Global Vegetation Models (DGVMs) have been coupled with Earth system models (ESMs). In DGVMs, global vegetation is commonly empirically categorized into a few discrete plant functional types (PFTs) by differentiating their phenological, morphophysiological, and bioclimatic properties. Although the PFT-approach is useful to capture the large-scale general features of plants, growing evidence from the ecology community has challenged the use of the plant-type specific parametrization in models and the omission of the intra-variation of PFTs. Modelling studies have also shown that the local climate is highly sensitive to the selection and combination of PFTs. Therefore, a less parameter-dependent approach, of which the results should be robust to the empirical selection of parameters, is critical to address vegetation-climate interaction in climate models.

Based on a process-based plant functioning trade-off scheme developed by Kleidon and Mooney (2000), we have set up a new vegetation model JeDi-BACH and have implemented the new model into the land component of the ICON-Earth System Model (ICON-ESM). The advantage of this new model is to obtain plant distribution as a result of environmental filtering. Plants are represented based on several well-known fundamental functional trade-offs that link the plant functions to abiotic and biotic attributes. For example, plants which partition more biomass to roots could improve their soil-water uptake and thereby reduce the stress from water shortage. Each plant functional aspect is defined by a set of plant-trait parameters that is randomly generated for each plant species. Hence, every parameter set realizes a plant growth strategy with different functional capabilities. Using a large number of randomly generated plant growth strategies, plants are allowed to ‘grow’ everywhere; but the environment will select the survivors. In such a way, plants dynamically adjust to the changing environment and meanwhile influence climate. We have done several simulations of present-day climate with JeDi-BACH and coupled to the atmosphere component of the ICON-ESM to investigate how such an adaptive ecosystem interacts with regional and global climate. Future investigations will focus on non-analogue climates (eg. Eocene with tropical vegetation at high latitudes) where in contrast to PFT-based DGVMs the new model allows vegetation to adjust consistently with climate because of its dynamic selection of plant traits by environmental filtering.

Kleidon, A. and Mooney, H. A.: A global distribution of biodiversity inferred from climatic constraints: Results from a process-based modelling study, Glob. Chang. Biol., 6(5), 507–523, doi:10.1046/j.1365-2486.2000.00332.x, 2000.

How to cite: Hu, P., Reick, C. H., Kleidon, A., and Claussen, M.: Exploring the influence of plant trait diversity on climate using the plant trait diversity model JeDi-BACH in an Earth system model, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2899, https://doi.org/10.5194/egusphere-egu21-2899, 2021.

Process-based models are needed to improve estimates of water and carbon cycles in variable climatic conditions. Yet, their utility is often limited by our inability to directly measure plant stomatal and hydraulic traits at scales suitable to quantify characteristics of whole ecosystems. Inferring such parameters from ecosystem-scale data with parsimonious models offers an avenue to address this limitation. To this aim, we use a simple representation of the water flux through the soil-plant-atmosphere continuum (SPAC) and derive a parameterization of Feddes-type soil water-limitation constraints on transpiration (expressed via a soil moisture dependent function β). This parameterization explicitly accounts for community-effective plant eco-physiological traits as encoded in the SPAC model parameters. We express analytically the fractional loss of conductivity in well-watered conditions and the soil saturation thresholds at which transpiration is down-regulated from its well-watered rate and at which transpiration ceases, as a function of non-dimensional parameter groups. These non-dimensional groups combine plant stomatal and hydraulic traits, soil texture and climate. We implement the theoretical β function into a soil water balance and infer distributions of plant traits which best-match FLUXNET observations in a range of biomes. Finally, we analyze the resulting non-dimensional groups to explore patterns in plant water use strategies. Our results indicate that non-dimensional groups reflect combinations of plant traits which are adapted to growing season environmental conditions and these groups may be more meaningful model parameters than individual traits at ecosystem scales. Additionally, using non-dimensional groups instead of focusing on individual parameters reduces risks of equifinality and provides future opportunities to exploit satellite data to quantify robust ecosystem-scale parameters. This analysis provides a parsimonious and functionally accurate alternative to account for ecosystem hydraulic controls and feedbacks and can help overcome limitations of commonly used empirical water-limitation constraints.

How to cite: Bassiouni, M., Manzoni, S., and Vico, G.: Parsimonious representation of plant water use strategies via non-dimensional parameter groups, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3966, https://doi.org/10.5194/egusphere-egu21-3966, 2021.

Usually hydraulic conductance and vulnerability are measured under extreme conditions never experienced by living plants (e. g. centrifugation, bench dehydration, and large pressure gradients). A common factor that is known to inhibit the water transport in plants is embolism, which is believed to occur either by air entry through the pit valves on the walls of the xylem, or by ex-solution of dissolved gases, or vaporization of water at very low pressures.

Here we explore possibilities to measure hydraulic conductance and induce embolism under close to natural conditions. The setup consists of a syringe pump to control water flow, where a twig is inserted in the flow path to measure its hydraulic conductivity using pressure and flow meters. This setup has enabled us to imitate natural conditions where transpiration rate induces a pressure difference between the sink (leaf) and source (root) along the flow path. It has also allowed us to induce flow in both directions through the twig without having to rotate or change out the sample. Using our setup, we found that the conductivity of the same twig was 50% lower when pulling compared to pushing. This can be explained by the emptying and filling of cut end vessels and the pressure gradient along the twig, which is induced by the flow rate and flow direction. Our findings are discussed in the context that currently employed methods for measuring wood hydraulic conductance employ either centrifugation, where water is pulled on both ends, or pushing of water by applying positive pressure on one end.

How to cite: Krieger, L., Schymanski, S., and Jansen, S.: Measuring plant hydraulic conductivity: Should we push or should we pull?, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2887, https://doi.org/10.5194/egusphere-egu21-2887, 2021.

Vegetation affects water balance partitioning via effects on incoming precipitation, local radiation balance and hydrological dynamics of soil. The extent of these effects is determined by plant functional traits. Commonly, the role of plant species on hydrological regulation has been assessed considering vegetation as homogeneous cover, even more, that approach underestimates the importance of species in this process. Nevertheless, in recent years, new focus has been placed on species study based on their functional traits and their roles in ecosystem functions as hydrological regulation. Still new tendencies are considering vegetation cover consisting of different species, each of them having different effects on hydrological regulation because they have different functional traits. In an 8-year old ecosystem restoration project established in Medellín (Colombia), we explored the relations between plant functional traits of 10 dominant species and ecohydrological processes that determine precipitation partitioning in the canopy via stemflow and throughfall. Here we show that functional traits describing tree crowns are significantly related with stemflow and throughfall. Our species exhibit differences in their functional traits and ecohydrological processes, forming a gradient of variation of ecohydrological processes and crown functional traits: from wide and less dense crowns in Alnus acuminata to smaller but more dense crowns in Quercus humboldtii, related with less throughfall temporal variability, and less stemflow temporal variability, respectively; the other species are placed along this gradient. This result suggests a complementary effect of species on the hydrological processes and consequently on the hydrological function, highlighting the importance of considering species diversity on hydrological regulation assessment. More specifically, our results emphasize the need to include information about the effects of species planted in ecological restoration projects over ecohydrological processes, via ecological criteria such as plant functional traits. This approach permits a more objective and complete study of hydrological regulation that brings key information for an adequate ecosystem management and restoration based on ecological roles of species that, through biological diversity, optimize ecosystem functions and services.

How to cite: Cano-Arboleda, L. V., Villegas, J. C., Restrepo, A. C., Ocampo-Montoya, E., and Quintero-Vallejo, E.: Tree species from Andean forest are complementary in their effect on ecohydrological processes, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3614, https://doi.org/10.5194/egusphere-egu21-3614, 2021.

Non-native plants, introduced through anthropogenic vectors, are causing changes at local up to global scales, altering species communities and entire ecosystems, modifying the structure of landscapes and even the functioning of biogeochemical cycles. Ultimately, however, changes induced by non-native plants occur locally at the level of species communities. With ongoing developments towards open-access information about species at increasingly fine spatial scales, the data and tools to better understand the consequences of vegetation changes caused by non-natives are available. Further, islands that commonly have less saturated ecosystems and unoccupied ecological niches with depauperate trophic cascades are particularly susceptible to the establishment of non-native plants and their potential impacts, respectively. Steep environmental gradients, unique plant communities with high percentages of endemism and a long history of human settlement alongside which hundreds of non-native species became established make the Canary Islands a suitable testing ground for invasion ecology. We aim at explaining divergence and overlap of native and non-native trait spaces within and between vegetation communities in this oceanic archipelago in order to assess the functional consequences of plant introductions for communities and ecosystems.

As a profound basis, we compiled a revised flora of the Canary Islands using local and global taxonomic databases combined with recent publications. Plant traits derived from comprehensive open-access sources and additional literature. At community level, we separated native and non-native species and their associated traits.

The analysis revealed strong differences in trait space divergence of non-native vs. native species within different vegetation communities. Surprisingly, certain traits such as woodiness of non-native species do not correlate with the role of this trait in plant communities previously dominated by native species. The inferences we can draw from our results differ from the conclusions made at the level of entire ecosystems, which underlines the relevance of investigating traits at community level.

We encourage implementing further studies at vegetation community level, to understand the direct changes caused by non-native species, build reliable explanatory models, enable targeted conservation measures and ultimately better understand patterns of biodiversity in the Anthropocene.

How to cite: Walentowitz, A. and Beierkuhnlein, C.: Trait spaces of non-native plants at community level in the Canary Islands, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11928, https://doi.org/10.5194/egusphere-egu21-11928, 2021.

Phylloplane or the microbial habitat on leaf surfaces is an integrated part of green infrastructure, with the potential to stimulate plant community productivity, affect plant fitness, and release of ecosystem services. Anthropogenic pressure, among which urbanization and related stressors was shown to affect the phylloplane microbial community composition and diversity. However, taxonomic characterization of the phylloplane with the aim to link it to the ecosystem functioning is not sufficient because it considers the microbial pool as a whole, not distinguishing between active, potentially active, dormant, and dead units. Meanwhile, only active microorganisms drive biochemical processes and determine the microbial community functioning. Determination of ecologically relevant microorganisms is linked to characterization the active microbial states but little is known on the phylloplane activity and its variation with the quality of the environment.

In this study, we attempted to verify how a change in environmental quality affects the phylloplane composition and activity. For this purpose, leaves of Betula pendula were sampled in Moscow (Russian Federation) along the three transects established starting from the road with heavy traffic and increasing gradually the distance from this pollution source. For determination of phylloplane activity and functional diversity a Microresp^TM tool, used generally for characterization of the soil microbiome, was adopted. The diversity of phylloplane microbiome was determined by its cultivation on nutrient media. Additionally, total genomic DNA was extracted from the leaf surface. Environmental quality was assessed by collecting the dust deposited on the leaf surface and analyzing its chemical composition on ICP-OES.

Activity of the phylloplane close to the road was 1.6 higher than far from it. Functional diversity or the ability to metabolize different substrates was on the contrary lower here. The amount of DNA was used to quantify the metabolic quotient (activity per DNA unit) which substantially increased in trees adjacent to the road. It could serve as an indication of the stress conditions or inefficiency of microbial community functioning with increase of contaminants concentrations. Elements that affected microbial activity were Ca and Zn. The amount of DNA declined with increase of Cu in leaf dust. While the total DNA and microbial functional diversity declined closer to the road, the amount of cultivable microorganisms, especially saprotrophic and enterobacteria, as well as the fungi species richness, increased on the leaf surface. This study showed that the distribution patterns under stress for phylloplane activity and functional diversity don’t correspond to those for species richness of cultivable fungi. The activity of phylloplane could be considered as an additional tool for bioindication of environmental quality.

The current research was financially supported by RFBR No 19-05-50112

How to cite: Ivashchenko, K., Korneykova, M., Novikov, A., Sazonova, O., Slukovskaya, M., Vetrova, A., Ermakova, A., Vasenev, V., and Gavrichkova, O.: Phylloplane of trees under stress in the city, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5206, https://doi.org/10.5194/egusphere-egu21-5206, 2021.

Allometric equations relating a tree’s vascular system with its leaf area and dry weight are developed for numerous forest species, in order to link their hydraulic architecture to carbon and biomass allocation. In 1964, Shinozaki et al. published the Pipe Model Theory (PMT) according to which, a given amount of leaves is supported by and is directly proportional to the area of the conductive tissue of the trunk. The present study aimed at testing whether PMT applies for R. pseudacacia plantations established for restoration and carbon sequestration purposes. A total of 25 trees of black locust grown at the restored former open-cast mining areas of the lignite center of the Hellenic Public Power Corporation (HPPC) in Ptolemaida and Aminteo, NW Greece, were destructively sampled. For each tree we determined its leaf area, foliage dry weight, diameter at breast height, as well as the cross-sectional areas of the trunk, the sapwood and the current sapwood at the stump height (0.30m), the breast height (1.3m), in the middle of the stem, at the base of live crown, at 1/3 and 2/3 of the length of the crown. The relationships of leaf area and foliage dry weight with the different cross-sectional areas at the selected stem heights were tested with simple and multiple linear regression models at p<0.001.

Among all tested relationships, PMT was more strongly verified by the linear relationship estimating both leaf area and foliage dry weight by the total cross-sectional area at the middle of the stem (R²=0.81). Sapwood area was found to be a less strong estimator of leaf area and foliage dry weight. The best relationships between sapwood area and leaf area / foliage were established when measured at the 1/3 of the length of the crown (R²=0.70 and 0.77, for leaf area and dry weight, respectively). The widely used relationship of sapwood at breast height to both leaf area and weight was less strong in our study (R²=0.66 and 0.68, for leaf area and dry weight, respectively). Furthermore, our results were not consistent with the theory of Shinozaki et al. (1964) that the ratio of leaf area to sapwood area increases from the top of the tree to the base of crown, where it is stabilized until breast height. These deviations may be due to the age of the studied plantations which does not exceed 30 years and the properties of the growth substrate consisting mainly of depositions from the extraction of lignite. The strongest allometric models for the estimation of leaf area and weight by tree diameter were built at breast height (R²=0.72) and at the base of live crown (R²=0.73), respectively. In addition, the trees’ diameter at the base of live crown could be reliably estimated by their diameter at breast height (R²=0.78). Our results were only partly consistent with the PMT. However, the established relationships may be useful for modelling and assessment of carbon allocation, water balance and growth of black locust plantations in restoration sites.

How to cite: Tziaferidis, S. R., Spyroglou, G., Fotelli, M., and Radoglou, K.: Allometric models for the estimation of leaf area and dry weight from sapwood and heartwood area in black locust (R. pseudacacia), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3999, https://doi.org/10.5194/egusphere-egu21-3999, 2021.

Data on plant traits are increasingly used to understand relationships between biodiversity and ecosystem processes. Large trait databases are sparse because they are compiled from many smaller and usually more local databases. This sparsity severely limits the potential for both multivariate and global data analyses, and so "gap-filling" (imputation) approaches are commonly used to predict missing trait data prior to analysis. Data imputation can result in large biases and circularity; yet, no best practice has evolved for the appropriate use of gap-filled data. Here, we use the TRY database, the largest global database of plant traits, in combination with the commonly used gap-filling algorithm, BayesianHierarchical Probabilistic Matrix Factorization (BHPMF), to address opportunities and problems introduced by gap-filling. BHPMF is the gap-filling method of choice for both TRY, and the large and widely used database sPLOT. It predicts missing trait data using the taxonomic hierarchy and observed patterns of trait variance and trait-trait correlations. We use three metrics: root mean square error estimates, coefficient of variation to assess univariate deviation, and silhouette indices to assess multivariate deviation and clustering strength. We show that gap-filling results in deviation of these metrics calculated for groupings at lower taxonomic levels (intra-specific and intra-genera), but less so at higher taxonomic levels (family) and for functional groups. Trait-trait correlations are preserved at all levels. The strength of deviations depends both on the percentage of gaps, and on data characteristics, e.g. intra-taxa variability. Gap-filling with dataset-external trait data generally ameliorates prediction error, but the deviations of intra-taxonomic variation measures depend on the content of the added data. We conclude that BHPMF gap-filling introduces little bias if specifically used for analyses of traits within functional groups, including growth forms and plant functional types (PFTs), as well as trait-trait correlations. However, we generally discourage their use for analyses of taxonomic groupings at or below the family level. In summary, our study supports decisions on when and how to integrate BHPMF gap-filled trait data in future studies. We conclude with selected best practices when using sparse databases.

How to cite: Joswig, J., Kattge, J., Kraemer, G., Mahecha, M., Rüger, N., Schaepman, M., Schrodt, F., Wirth, C., and Schuman, M.: When does gap filling of trait data confound taxonomic and functional analyses?, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13954, https://doi.org/10.5194/egusphere-egu21-13954, 2021.

Quantitative analysis of structure and function of plants has become the major bottleneck in basic plant research and applied use of plants in breeding or agricultural management. This is particularly important for sustainable intensification of crop production to ensure the amount and quality of plant biomass for human nutrition and industry in times of climate change. In recent years, significant interdisciplinary approaches have been started to establish plant phenotyping infrastructure with non-invasive methods that allow to quickly and non-invasively assessing the condition and properties of plants in the laboratory, greenhouse or field, make these data accessible through data and computational services and allow data reuse for meta-analysis or modelling.

In this presentation, we will outline the recent developments to integrate plant phenotyping across scales from lab to field including common data management approaches. The ESFRI research infrastructure EMPHASIS is developing a pan European infrastructure based of the portfolio of existing national plant phenotyping centers. The goal is to: i) provide a instrumented facilities for user access for quantitative trait assessment, ii) link data acquisition with data management and modelling, iii) develop, evaluate and disseminate knowledge and novel technologies. We will showcase phenotyping of quantitative traits under controlled and specifically field conditions providing novel inside on plant environment interaction for example in dedicated free air CO2 enrichment facilities and illustrate the development of pan-European information system making these data reusable. Finally, we will introduce the latest activities of IPPN e.V. is a networking platform linking the plant phenotyping centers and enabling close interaction across the globe.

How to cite: Pieruschka, R., Fahrner, S., and Schurr, U.: EMPHASIS: European infrastructure for multi-scale plant phenotyping and simulation for food security in a changing climate, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1372, https://doi.org/10.5194/egusphere-egu21-1372, 2021.