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Soil seed bank is an important source of resilience of plant communities who suffered disturbances. We analysed the effect of an intense fire in the soil seed bank of a semi-arid shrubland of Córdoba Argentina. We asked if the fire affected seed abundance, floristic and functional composition of the soil seed bank at two different layers (0-5 cm and 5-10 cm), and if fire could compromise the role of the soil seed bank as a source of resilience for the vegetation. We collected soil samples from a burned site and from a control site that had not burned. Samples were installed in a greenhouse under controlled conditions. During 12 months, we recorded all germinated seedlings. We compare soil seed bank with pre-fire vegetation in terms of floristic and functional composition. The high-intensity fire deeply affected the abundance of seeds in the soil, but it did not affect its floristic or functional composition. Floristic and functional composition of soil seed banks - at burned and unburned sites-differed markedly from that of the pre-fire vegetation, although a previous study at the same site indicated high resilience after fire of this plant community. Our results indicate that resilience of this system is not strongly dependent on direct germination from seeds buried in the soil. Other sources of resilience, like colonization from neighbouring vegetation patches and resprouting from underground organs appear to gain relevance after an intense fire. [ABSTRACT FROM AUTHOR]

Abstract: Aim: Stomata regulate CO2 uptake, water‐vapour loss and uptake of gaseous pollutants. Jarvis‐type models that apply multiple‐constraint functions are commonly used to estimate stomatal conductance (gs), but most parameters for plant functional types (PFTs) have been estimated using limited information. We refined the data set of key components of the gs response to environmental factors in global PFTs. Location: Global. Time period: Data published in 1973–2015. Major taxa studied: Woody plants and major crops (rice, wheat and maize). Methods: We reviewed 235 publications of field‐observed gs for the parameterization of Jarvis‐type models in global PFTs. The relationships between stomatal parameters and climatic factors [mean annual air temperature (MAT) and mean annual precipitation (MAP)] were assessed. Results: We found that maximal stomatal conductance (gmax) in global woody plants was correlated with MAP rather than with MAT. The gmax of woody plants on average increased from 0.18 to 0.26 mol/m2/s with an increase in MAP from 0 to 2,000 mm. Models, however, can use a single gmax across major crops (0.44 mol/m2/s). We propose similar stomatal responses to light for C3 crops and woody plants, but C4 crops should use a higher light saturation point of gs. Stomatal sensitivity to vapour‐pressure deficit (VPD) was similar across forest PFTs and crops, although desert shrubs had a relatively low sensitivity of stomata to VPD. The optimal temperature for gs increased by 1 °C for every 3.0 °C of MAT. Stomatal sensitivity to predawn water potential was reduced in hot and dry climate. The fraction of nighttime conductance to gmax (0.14 for forest trees, 0.28 for desert shrubs and 0.13 for crops) should be incorporated into the models. Main conclusions: This analysis of global gs data provides a new summary of gs responses and will contribute to modelling studies for plant–atmosphere gas exchange and land‐surface energy partitioning. [ABSTRACT FROM AUTHOR]

* We studied the impact of aridity on leaf and mesophyll traits in dominant and very abundant plant species of Eurasian steppe plant communities. We covered a 500-km latitudinal gradient across three vegetation zones in the Volga region of southern European Russia. * Whole-leaf traits, volumetric fractions of leaf tissues, quantitative parameters of photosynthetic cells and chloroplasts, and chlorophyll, carbon (C) and nitrogen (N) contents were analyzed and related to plant functional type (PFT), type of mesophyll anatomy, phylogeny and climate aridity. * The proportions of prevailing PFTs in the communities, such as C3 monocots, C3 dicots with dorsiventral and isopalisade anatomy and C4 dicots, changed with increasing aridity which influenced the whole-leaf parameters and tissue composition in the leaf. Leaf mass per unit area and leaf thickness slightly increased along the aridity gradient, but the most significant changes were observed in the mesophyll. Mesophyll cell surface area, chloroplast number and chloroplast surface area per unit leaf area were higher in C3 plants growing in the desert steppe compared with those of the forest steppe, while chlorophyll content per single chloroplast and per unit N content as well chlorophyll a/b ratio decreased. * Our results identify a suite of mesophyll traits as a typical 'syndrome' of increasingly drought-adapted steppe plants. [ABSTRACT FROM AUTHOR]

Abstract: Questions: The rapid climate warming in tundra ecosystems can increase nutrient availability in the soil, which may initiate shifts in vegetation composition. The direction in which the vegetation shifts will co‐determine whether Arctic warming is mitigated or accelerated, making the understanding of successional trajectories urgent. One of the key factors influencing the competitive relationships between plant species is their access to nutrients, depending on the depth where they take up most nutrients. However, nutrient uptake at different soil depths by tundra plant species that differ in rooting depth is unclear. Location: Kytalyk Nature Reserve, northeast Siberia, Russia. Methods: We injected 15N to 5 cm, 15 cm and the thaw front of the soil in a moist tussock tundra. The absorption of 15N by grasses, sedges, deciduous shrubs and evergreen shrubs from the three depths was compared. Results: The results clearly show a vertical differentiation of N uptake by these plant functional types, corresponding to their rooting strategy. Shallow‐rooting dwarf shrubs were more capable of absorbing nutrients from the upper soil than from deeper soil. Deep‐rooting grasses and sedges were more capable of absorbing nutrients from deeper soil than the dwarf shrubs. The natural 15N abundances in control plants also indicate that graminoids can absorb more nutrients from the deeper soil than dwarf shrubs. Conclusions: Our results show that graminoids and shrubs in the Arctic differ in their N uptake strategies, with graminoids profiting from nutrients released at the thaw front, while shrubs mainly forage in upper soil layers. Our results suggest that tundra vegetation will become graminoid‐dominated as permafrost thaw progresses and nutrient availability increases in the deep soil. [ABSTRACT FROM AUTHOR]

Vegetation succession is known to affect carbon-cycling patterns of recovering cutover peatlands, displayed as shifts in emissions of the greenhouse gases CO 2 and CH 4 . However, the related plant-microbe interactions are still poorly understood. We aimed to link the recovery of the organisms responsible for CH 4 turnover, the methanogens and the methanotrophs, to the re-vegetation related compositional changes of three functional plant types ( Sphagna , sedges and shrubs). In peat layers, the Sphagnum coverage was the most influential factor for the activity, abundance and community structures of both these microbial groups, demonstrating a succession pattern towards a pristine stage. Analysis of mcrA and pmoA genes revealed Methanoregulaceae and Methylocystis as the most dominant methanogens and methanotrophs, respectively. The relatively fast recovery of both CH 4 production and oxidation in the peat layers supports earlier flux based results from these same fen-type peatland sites. In contrast to peat, CH 4 oxidation in living Sphagnum mosses appeared to be independent of vegetation succession as CH 4 oxidation potential was similar throughout the succession stages. This indicated that Sphagnum may be a valuable CH 4 biofilter especially in the early re-vegetation stages when the oxidation in the peat has not yet recovered. Therefore, we recommend Sphagnum transplantation as a tool for climate friendly peatland restoration with faster recovery of the carbon sink function and altered CH 4 emissions. [ABSTRACT FROM AUTHOR]

• FOD indices are more robust for estimating leaf photosynthetic parameters. • 1.50- and 1.60-order D-type indices performed best for Vcmax and Jmax estimations. • High order-derived indices are more sensitive to random noise. The maximum carboxylation rate (Vcmax) and the maximum electron transport rate (Jmax) are representative parameters describing the gas exchange properties of leaves. Non-destructive measurements of these parameters are valuable for tracing the physiological status and productivity of a plant. The spectral vegetation index, as a simple and efficient approach, has been applied to estimate these two parameters. However, most indices used are derived from original or integer-order rather than fractional-order derivatives (FOD), despite increasing evidence of their advantages in terms of tracing diverse plant properties. In this study, we attempt to derive photosynthetic capacity parameters from FOD indices based on a composite hyperspectral spectroscopy dataset covering various conditions. Our results show that the FOD can be utilized to develop more robust indices for obtaining photosynthetic capacity parameters. In particular, the D-type indices calculated from the 1.50-order and 1.60-order derivatives produced the highest accuracies for the estimation of Vcmax and Jmax. The performance of these proposed indices, however, differed for different plant functional types and had a high sensitivity to random noise. The results of the present research show that FOD indices have the potential to estimate leaf photosynthetic parameters, and are therefore to support hyperspectral information on estimating plant properties. [ABSTRACT FROM AUTHOR]

• Plot and plant functional types greenness was extracted from repeat digital images. • Plot greenness closely tracked plot photosynthesis. • Plot greenness was correlated with soil moisture during mid- to late- season. • Plot greenness response to rainfall pulses was delayed under few, large events. • Perennial grass dominated the lagged response under few, large events. Across large portions of the western United States, drought intervals are increasing, often accompanied by larger-magnitude rainfalls. Semi-arid ecosystems are expected to be especially responsive to such temporal repackaging of rainfall because of their high sensitivity to variation in soil moisture. We conducted a field manipulation experiment to evaluate the impacts of summer rainfall repackaging (small/many events to large/few events with a fixed total seasonal amount) on a semi-arid mixed annual/perennial bunchgrass ecosystem. We monitored the sensitivity of plant greenness and productivity to soil moisture under rainfall pulses by combining automated, high-frequency repeat digital images at both plot- and plant functional type- level, whole plot CO 2 uptake measurements, and continuous in-situ soil moisture data. We found that plot greenness was closely correlated with gross primary productivity across all rainfall repackaging treatments (R = 0.82). Plot greenness was weakly correlated to soil moisture at the beginning of the growing season but showed a significant positive correlation during peak and late growing season. Notably, we found a significant lag time of ∼5 days between changes in soil moisture and canopy greenness under large/few events, while there was no lag under small/many events. This time lag was found to be driven by perennial grass greenness and its sensitivity to the relatively deep soil water infiltration observed with large/few rainfall events. Predicting semi-arid grassland responses to soil moisture dynamics under ongoing rainfall repackaging, and subsequent impacts on the regional to global carbon budget, should consider plant communities' phenological characteristics and functional type composition. [ABSTRACT FROM AUTHOR]

Global change, like droughts, can destabilize the carbon sink function of peatlands, either directly or indirectly through changes in plant community composition. While the effects of drought and plant community composition on individual carbon (C) related processes are well understood, their effect on multiple C-related processes simultaneously—multifunctionality—is poorly known. We studied the effect of drought on four C-related processes (net and gross CO2 exchange, methane fluxes, and dissolved organic carbon content) in a plant removal experiment. Plant functional type (PFT) removal (graminoids, herbs, Polytrichum spp., incl. combinations) negatively affected multifunctionality; most markedly when all PFTs were removed. Our results corroborate a negative drought effect on C-related multifunctionality. Drought reduced multifunctionality, and this reduction was again largest when all PFTs were removed. Our data further indicate that much of these negative drought effects were carried over and maintained from the initial removal treatment. These results suggest that while a high diversity in plant functional types is associated to high C-related multifunctionality, plant community assembly does not drive the ability of peatlands to withstand the negative impacts of drought on multifunctionality. Hence, to safeguard the carbon cycling function in intact peatlands, the effects of climate change on the functional composition of the peatland plant community needs to be minimized.

The people of the Mongolian steppe have maintained a sustainable, nomadic lifestyle. However, several ecological processes are threatening their way of life. Ecological changan be detected through the analysis of quantitative and qualitative data. It is therefore, imperative to develop a sustainable rangeland management system aimed at combating desertifi cation. In this study we quantitatively and qualitatively describe several western Mongolian steppe plant communities by examining species composition, plant volume and community structure. Study sites were located in the Uvs and Khovd provinces and had all been affected by livestock grazing. A total of 48 species were found. Stipa krylovii , S . gobica , Cleistogenes songorica , Koeleria cristata and Ajania achilleoides were dominant. There was a signifi cant relationship between biomass and plant volume at all sites. Study sites were classifi ed into four groups using cluster analysis, based on the presence or absence of several species. More than 90% of plant volumes at all groups were perennial grasses and perennial forbs. The ratio of C 3 to C 4 plants at site 3 was reversed in comparison to the other sites. Species highly palatable to livestock were dominant at all sites. To ensure the sustainable use of biological resources in these arid areas, these fi ndings should be taken into account in designing land-use plans.

Secondary succession after wildfire usually leads to vegetation types that can differ with the original vegetation in terms of forage productivity and community stability. Plant functional types (PFTs) can be used as ecological indices for assessing effects of disturbances on the natural plant communities. Accordingly, this research was aimed to identify, classify and analyze PFTs in three rangeland sites: burnt in 2004, in 2008, and control (2010), in Jowzak, Northern Khorasan, Iran. Floristic list, percentage cover and 24 morphological, phonological and reproductive plant traits were recorded within 1m2quadrates. PFT’s were determined by applying hierarchical cluster analyses and discriminant function analysis on the matrices of 45 species24 traits and 45 species3 sites, using SPSS software. Four different PFTs were identified. Leaf wet weight, life forms and Twig dry matter contents were the most important traits for PFT classification. Two functional types identified as adapted to fire, and two groups as functional types sensitive to fire. According to the results of this research, the most important indices for the effect of fire on secondary succession of Jowzak rangelands can be the reduction of hemicryptophytes perennial geophytes and annuals, increase of plant height , seed size, seed weight, specific leaf area and leaf dry matter content, and decrease of stem weight, leaf and twig dry matter content.

Research on global climate change requires plant functional type (PFT) products. Although several PFT mapping procedures for remote sensing imagery are being used, none of them appears to be specifically designed to map and evaluate PFTs over broad mountainous areas which are highly relevant regions to identify and analyze the response of natural ecosystems. We present a methodology for generating soft classifications of PFTs from remotely sensed time series that are based on a hierarchical strategy by integrating time varying integrated NDVI and phenological information with topography: (i) Temporal variability: a Fourier transform of a vegetation index (MODIS NDVI, 2006 to 2010). (ii) Spatial partitioning: a primary image segmentation based on a small number of thresholds applied to the Fourier amplitude. (iii) Classification by a supervised soft classification step is based on a normalized distance metric constructed from a subset of Fourier coefficients and complimentary altitude data from a digital elevation model. Applicability and effectiveness is tested for the eastern Tibetan Plateau. A classification nomenclature is determined from temporally stable pixels in the MCD12Q1 time series. Overall accuracy statistics of the resulting classification reveal a gain of about 7% from 64.4% compared to 57.7% by the MODIS PFT products.

The objective of this paper was to evaluate the use of in situ normalized difference vegetation index (NDVIis) and Moderate Resolution Imaging Spectroradiometer NDVI (NDVIMD) time series data as proxies for ecosystem gross primary productivity (GPP) to improve GPP upscaling. We used GPP flux data from 21 global FLUXNET sites across main global biomes (forest, grassland, and cropland) and derived MODIS NDVI at contrasting spatial resolutions (between 0.5 × 0.5 km and 3.5 × 3.5 km) centered at flux tower location. The goodness of the relationship between NDVIis and NDVIMD varied across biomes, sites, and MODIS spatial resolutions. We found a strong relationship with a low variability across sites and within year variability in deciduous broadleaf forests and a poor correlation in evergreen forests. Best performances were obtained for the highest spatial resolution at 0.5 × 0.5 km). Both NDVIis and NDVIMD elicited roughly three weeks later the starting of the growing season compared to GPP data. Our results confirm that to improve the accuracy of upscaling in situ data of site GPP seasonal responses, in situ radiation measurement biomes should use larger field of view to sense an area, or more sensors should be placed in the flux footprint area to allow optimal match with satellite sensor pixel size.

Understanding and monitoring the dynamics of rangeland heterogeneity through time and across space is critical for the effective management and conservation of rangeland systems and the sustained supply of the ecosystem goods and services they provide. Conventional approaches (both field-based and remote sensing) to monitoring rangeland productivity fail to effectively capture important aspects of this heterogeneity. While field methods can effectively capture high levels of detail at fine spatial and temporal resolutions, they are limited in their applicability and scalability to larger spatial extents and longer time periods. Alternatively, remote sensing based approaches that scale broad spatiotemporal extents simplify important heterogeneity occurring at fine scales. We address these limitations to monitoring rangeland productivity by combining a continuous plant functional type (PFT) fractional cover dataset with a Landsat derived gross primary production (GPP) and net primary production (NPP) model. Integrating the annual PFT dataset with a 16-day Landsat normalized difference vegetation (NDVI) composite dataset enabled us to disaggregate the pixel level NDVI values to the sub-pixel PFTs. These values were incorporated into the productivity algorithm, enabling refined estimations of 16-day GPP and annual NPP for the PFTs that composed each pixel. We demonstrated the results of these methods on a set of representative rangeland sites across the western United States. Partitioning rangeland productivity to sub-pixel PFTs revealed new dynamics and insights to aid the sustainable management of rangelands.

Logged tropical forests represent a major opportunity for preserving biodiversity and sequestering carbon, playing a large role in meeting global forest restoration targets. Left alone, these ecosystems have been expected to undergo natural regeneration and succession towards old growth forests, but extreme drought events may challenge this process. While old growth forests possess a certain level of resilience, we lack understanding as to how logging may affect forest responses to drought. This study examines the drought–logging interaction in seedling dynamics within a landscape of logged and unlogged forests in Sabah Malaysia, based on 73 plots monitored before and after the 2015–16 El Niño drought. Drought increased seedling mortality in all forests, but the magnitude of this impact was modulated by logging intensity, with forests with lower canopy leaf area index and above-ground biomass experiencing greater drought induced mortality. Moreover, community traits in more heavily logged forests shifted towards being more ruderal after drought, suggesting that the trajectory of forest succession had been reversed. These results indicate that with reoccurring strong droughts under a changing climate, logged forests that have had over half of their biomass removed may suffer permanently arrested succession. Targeted management interventions may therefore be necessary to lift the vulnerable forests above the biomass threshold.

Leaf tissue fluxes of five Pampa biome grasses ( Andropogon lateralis, Aristida laevis, Axonopus affinis, Paspalum notatum and Paspalum plicatulum) were evaluated in a natural pasture under rotational stocking with heifers in the spring and summer from October 2010 to April 2011. The experimental design was completely randomized, with two grazing intervals, defined by thermal sums of 375 and 750 degree-days, and the five grass species. The evaluated species had a higher growth flux and balance between the fluxes when subjected to a grazing interval of 750 degree-days and a higher real efficiency of utilization when subjected to grazing interval of 375 degree-days. Andropogon lateralis showed the highest growth, intake and senescence fluxes: 3·61, 2·37 and 3·04 kg DM ha−1 day−1 respectively. Aristida laevis had the lowest real efficiency of utilization. [ABSTRACT FROM AUTHOR]

The impacts of year-round nocturnal warming or late spring rain exclusion on three plant functional types were studied in a plot-scale climate simulation experiment in a semiarid sand forest-steppe of Central Hungary. Ecophysiological traits were followed through six years for the C3 bunch grass Festuca vaginata, the spreading C4 grass Cynodon dactylon and shrub-sized root suckers of Populus alba. In general, experimental treatments had slighter effects than weather fluctuations yielding extremities did. Populus alba responded to nocturnal warming with developing slenderer leaves. Rain exclusion reduced leaf physiological activity or growth, but only during or just after the treatment, and in certain years. When assessing treatment and background climatic variation effects together, in spring, leaf area growth was consistently stimulated by increasing temperature, but decreased with longer rainless periods for P. alba and F. vaginata. Physiological responses in spring indicated low temperature limitation for C. dactylon, and both low and high temperature control for P. alba. Longer summer droughts reduced leaf gas exchange, particularly for F. vaginata with substantial drop in photochemical activity and chlorophyll content. These results suggest that shallow rooted C3 bunch grasses can be the most susceptible to climatic variation, thus their abundance is expected to decline in the Pannonian forest-steppe. In contrast, plants having deeper roots and clonal integration will probably be less affected by the projected warming and drying climate. C4 photosynthesis or southern geographical distribution may also be beneficial, thus, the abundance of such species is expected to diminish less or even increase. [ABSTRACT FROM AUTHOR]

Climate change-induced rise of air temperatures and the increase of extreme climatic events, such as droughts, will largely affect plant growth and hydraulics, leading to mortality events all over the globe. In this study, we investigated the growth and hydraulic responses of seedlings of contrasting functional types. Pinus sylvestris, Quercus spp. and Castanea sativa seedlings were grown in a common garden experiment under four treatments: control, air warming, drought and their combination during two consecutive growing periods. Height and diameter increments, stomatal conductance and stem water potentials were measured during both growing seasons. Additionally, hydraulic parameters such as xylem-specific native and maximum hydraulic conductivities, and native percentage of loss of conductivity were measured at the end of the entire experiment. Our results clearly pointed to different adaptive strategies of the studied species. Scots pine displayed a relatively isohydric behavior with a strict stomata control prohibiting native embolism whereas sweet chestnut and oak as relatively anisohydric species displayed an increased loss of native conductivity as a results of low water potentials. Seasonal timing of shoot and diameter growth also differed among functional types influencing drought impacts. Additionally, the possibility of embolism reversal seemed to be limited under the study conditions. [ABSTRACT FROM AUTHOR]

Both overabundant ungulates and invasive shrubs negatively impact forest floor plants, but few studies have investigated their interaction. We tested for direct effects and interactions of white-tailed deer, Odocoileus virginianus , and the invasive shrub, Lonicera maackii , on forest floor plant richness and composition in five sites in southwest Ohio. In each site a deer exclosure and an unfenced plot (each 20 × 20 m) were established in 2010; in half of each plot all L. maackii was removed. Each spring and summer, 2011–2014, percent cover of each plant species in 50 × 20 cm subplots was recorded. Herb layer species richness was greater where L. maackii was removed, and this effect tended to be stronger where deer were excluded. Species composition in the spring was not affected by treatments, whereas summer species composition (in one year) was affected by L. maackii treatment. Cover of graminoids, spring herbs, and vines were lower where L. maackii was intact, whereas cover of shrubs and tree seedlings were lower, and cover of bare ground higher, where deer had access. Our findings reveal that deer and L. maackii negatively impact different components of the forest herb layer. However, the combined effects on species richness tended to be antagonistic (less than additive), possibly due to deer browse reducing the cover of this invasive shrub. This suggests that the diversity of the herb layer will be enhanced more by both removal of invasive shrubs and reduction of the deer population than by either management action alone. [ABSTRACT FROM AUTHOR]

Ecosystem maps are foundational tools that support multi-disciplinary study design and applications including wildlife habitat assessment, monitoring and Earth-system modeling. Here, we present continuous-field cover maps for tundra plant functional types (PFTs) across ~125,000 km2 of Alaska’s North Slope at 30-m resolution. To develop maps, we collected a field-based training dataset using a point-intercept sampling method at 225 plots spanning bioclimatic and geomorphic gradients. We stratified vegetation by nine PFTs (e.g., low deciduous shrub, dwarf evergreen shrub, sedge, lichen) and summarized measurements of the PFTs, open water, bare ground and litter using the cover metrics total cover (areal cover including the understory) and top cover (uppermost canopy or ground cover). We then developed 73 spectral predictors derived from Landsat satellite observations (surface reflectance composites for ~15-day periods from May–August) and five gridded environmental predictors (e.g., summer temperature, climatological snow-free date) to model cover of PFTs using the random forest data-mining algorithm. Model performance tended to be best for canopy-forming PFTs, particularly deciduous shrubs. Our assessment of predictor importance indicated that models for low-statured PFTs were improved through the use of seasonal composites from early and late in the growing season, particularly when similar PFTs were aggregated together (e.g., total deciduous shrub, herbaceous). Continuous-field maps have many advantages over traditional thematic maps, and the methods described here are well-suited to support periodic map updates in tandem with future field and Landsat observations. [ABSTRACT FROM AUTHOR]

The ecological concept of Plant Functional Types (PFTs), which refers to the assemblage of plants with certain functional traits, has been introduced for the study of plant responses to the environment change and human disturbance. Taking the alpine meadow community in the Zoigê Plateau as a study case, this paper classified PFTs in terms of plant nutrition traits. The sequential results are as follows. (1) The main herbages in the Zoigê Plateau included 16 species in 5 families. Among the five families, Cyperaceae vegetation accounted for 81.37% of herbage area in total, while the remaining 4 families occupied less than 20%. As for the species, Kobresia setchwanensis Hand.-Maizz. was dominant, accounting for 48.74% of the total area; while the remaining 51.26% was comprised of Polygonum viviparum L., Anaphalis fiavescens Hand.-Mazz., Stipa aliena Keng and other species. (2) By using the Principal Component Analysis (PCA), the assessment of herbages nutrition was carried out based on the comprehensive multi-index evaluation model. Polygonum viviparum L. had the highest nutritional value score (1.43), and Stipa aliena Keng had the lowest (-1.40). Nutritional value of herbage species had a significantly positive correlation with altitude ( P<0.01) in the Zoigê Plateau. (3) Based on the nutritional values, herbages in the Zoigê Plateau could be grouped into 3 nutrition PFTs (high, medium and low) by using the Natural Breaks (Jenks) method. [ABSTRACT FROM AUTHOR]

The contributions of non-vascular plants (NVPs) to ecosystem function can be significant in high latitude and high altitude ecosystems and yet their inclusion in trait-based studies is rare. Our aim in this paper is to argue for a more thorough and widespread inclusion of NVPs in trait-based studies of ecosystem function. We focused on three specific objectives, (i) to review and summarize the current knowledge base as to how NVP traits are measured and used in assessing ecosystem function, (ii) to highlight challenges in incorporating vascular plants (VPs) and NVPs together in trait-based studies, and (iii) discuss a framework by which VPs and NVPs can be included in explaining ecosystem function. From a literature search of the Web of Science database we found that the majority of trait-based studies examined mostly vascular plants (VPs), occasionally VPs and NVPs separately, but rarely the two groups together to describe ecosystem function. To date compared to VPs, assessment of the contributions of NVPs to ecosystem function has remained relatively unexplored. Plant communities comprising VPs and NVPs can influence, and in turn be influenced by their habitats. We argue that the response and effect traits of VPs and NVPs are comparable and that classifying NVPs simply as “mosses” and “lichens” and assessing their functions as such is inadequate. We summarized and identified particular measurable traits of both VPs and NVPs that have significant effects on nutrient cycling and community assembly. Future studies in areas where NVPs are abundant should include both VPs and NVPs, aggregated at the finest taxonomic resolution possible to relate ecosystem processes such as cycling of matter and plant community assembly. [ABSTRACT FROM AUTHOR]

Climate warming is faster in the Arctic than the global average. Nutrient availability in the tundra soil is expected to increase by climate warming through (i) accelerated nutrient mobilization in the surface soil layers, and (ii) increased thawing depths during the growing season which increases accessibility of nutrients in the deeper soil layers. Both processes may initiate shifts in tundra vegetation composition. It is important to understand the effects of these two processes on tundra plant functional types., We manipulated soil thawing depth and nutrient availability at a Northeast-Siberian tundra site to investigate their effects on above- and below-ground responses of four plant functional types (grasses, sedges, deciduous shrubs and evergreen shrubs). Seasonal thawing was accelerated with heating cables at c. 15 cm depth without warming the surface soil, whereas nutrient availability was increased in the surface soil by adding slow-release NPK fertilizer at c. 5 cm depth. A combination of these two treatments was also included. This is the first field experiment specifically investigating the effects of accelerated thawing in tundra ecosystems., Deep soil heating increased the above-ground biomass of sedges, the deepest rooted plant functional type in our study, but did not affect biomass of the other plant functional types. In contrast, fertilization increased above-ground biomass of the two dwarf shrub functional types, both of which had very shallow root systems. Grasses showed the strongest response to fertilization, both above- and below-ground. Grasses were deep-rooted, and they showed the highest plasticity in terms of vertical root distribution, as grass root distribution shifted to deep and surface soil in response to deep soil heating and surface soil fertilization respectively., Synthesis. Our results indicate that increased thawing depth can only benefit deep-rooted sedges, while the shallow-rooted dwarf shrubs, as well as flexible-rooted grasses, take advantage of increased nutrient availability in the upper soil layers. Our results suggest that grasses have the highest root plasticity, which enables them to be more competitive in rapidly changing environments. We conclude that root vertical distribution strategies are important for vegetation responses to climate-induced increases in soil nutrient availability in Arctic tundra, and that future shifts in vegetation composition will depend on the balance between changes in thawing depth and nutrient availability in the surface soil. [ABSTRACT FROM AUTHOR]

Plant functional types ( PFT) are increasingly used to outline biome-scale plant-environment relationship and predict global change effects on community structure. However, the potentials and limitations of the PFT approach have to be tested as they can be less sensitive than trait-based or species-level approaches. Here, we compare the responses of deciduous-evergreen shrub PFTs and species to gradual snow-related environmental conditions by also considering effects of aboveground architectural traits and neighboring shrubs. Five deciduous species and four evergreen dwarf shrub species were transplanted to be exposed to four levels of winter snow cover across mesotopographic gradients in northern Fennoscandian tundra. The survival and growth of individually tagged shoots were monitored over one year, and the change in cover of shrubs was monitored over four years. Evergreen species showed higher resistance to environmental severity and generally benefitted from higher abundance of neighboring shrubs. Deciduous species exhibited negligible to drastic responses to snow thickness and neighboring shrubs tended to have a negative effect on their performance and survival. Tall shoots of deciduous shrubs survived poorly under the thinnest snow cover. Overall, deciduous and evergreen PFTs showed modest differences in their performances along the gradient. Our results show that deciduous-evergreen leaf phenology categories predict shrub responses to changing environmental conditions only to a limited extent. Our findings highlight strong species-specific responses especially among deciduous shrubs, and a differential role of plant-plant interactions for shrubs. Our results emphasize that distribution patterns of arctic-alpine shrubs and shrub community responses to altered snow regimes depend on species-level plant functional attributes, species interactions and species-specific sensitivities to environmental severity. [ABSTRACT FROM AUTHOR]

Despite the importance of future carbon (C) pools for policy and land management decisions under various climate change scenarios, predictions of these pools under altered climate vary considerably. Chronic warming will likely impact both ecosystem C fluxes and the abundance and distribution of plant functional types (PFTs) within systems, potentially interacting to create novel patterns of C exchange. Here, we report results from a 3-year warming experiment using open top chambers (OTC) on the Tibetan Plateau meadow grassland. Warming significantly increased C uptake through gross primary productivity (GPP) but not ecosystem respiration (ER), resulting in a 31.0% reduction in net ecosystem exchange (NEE) in warmed plots. The OTC-induced changes in ecosystem C fluxes were not fully explained by the corresponding changes in soil temperature and moisture. Warming treatments significantly increased the biomass of graminoids and legumes by 12.9 and 27.6%. These functional shifts were correlated with enhanced local GPP, but not ER, resulting in more negative NEE in plots with larger increases in graminoid and legume biomass. This may be due to a link between greater legume abundance and higher levels of total inorganic nitrogen, which can potentially drive higher GPP, but not higher ER. Overall, our results indicate that C-climate feedbacks might be closely mediated by climate-induced changes in PFTs. This highlights the need to consider the impacts of changes in PFTs when predicting future responses of C pools under altered climate scenarios. [ABSTRACT FROM AUTHOR]

Question Did vegetation of former coppice-with-standards woodlands, which were in conversion towards high forest for about 100 yrs, change over the last 41 yrs (1970-2011)? What were the main drivers of vegetation change? Location Dransfeld Plateau, central Germany. Methods Repetition of 85 historical semi-permanent vegetation plots located in 13 forest patches on limestone soil. Differences in species composition and plant functional types between historical and recent plots were analysed using a block multi-response permutation procedure (bMRPP), NMDS, indicator species analysis (ISA) and ANOVA. Results We found significant changes in all vegetation layers. In the tree layer, Fagus sylvatica and Hedera helix had increased, while Quercus robur and Carpinus betulus had decreased. In the understorey, tree regeneration had strongly increased. In the herbaceous layer, species richness had decreased from 30 to 24 species per 100 m², and the abundance of plant functional types had changed: the proportion of geophytes and therophytes had increased, while the proportion of hemicryptophytes had decreased. Spring-green species (i.e. species active mainly before tree foliation) had increased, while summer-green species had decreased. In addition, the estimated mean SLA of herbaceous species had increased. The proportion of closed-forest species had slightly increased, while the proportion of species of forest edges and clearings had decreased. NMDS ordination separated the herbaceous layers from 1970 and 2011 along the second axis, which correlated with the indicator values for continentality (decrease over time) and N (increase over time). Conclusions Although the stands still shared many characteristics of coppice-with-standards woodlands, the vegetation had clearly shifted towards that of darker and more nutrient-rich forest. This indicates both a marked legacy of historic coppice management and a strong influence of recent high forest management, as well as N deposition. [ABSTRACT FROM AUTHOR]

Several techniques have been used to model the area covered by biomes or species. However, most models allow little freedom of choice of response variables and are conditioned to the use of climate predictors. This major restriction of the models has generated distributions of low accuracy or inconsistent with the actual cover. Our objective was to characterize the environmental space of the most representative biomes of Brazil and predict their cover, using climate and soil-related predictors. As sample units, we used 500 cells of 100 km for ten biomes, derived from the official vegetation map of Brazil (IBGE 2004). With a total of 38 (climatic and soil-related) predictors, an a priori model was run with the random forest classifier. Each biome was calibrated with 75% of the samples. The final model was based on four climate and six soil-related predictors, the most important variables for the a priori model, without collinearity. The model reached a kappa value of 0.82, generating a highly consistent prediction with the actual cover of the country. We showed here that the richness of biomes should not be underestimated, and that in spite of the complex relationship, highly accurate modeling based on climatic and soil-related predictors is possible. These predictors are complementary, for covering different parts of the multidimensional niche. Thus, a single biome can cover a wide range of climatic space, versus a narrow range of soil types, so that its prediction is best adjusted by soil-related variables, or vice versa. [ABSTRACT FROM AUTHOR]

Aims Contrasting leaf types with different leaf life spans represent different adaptive strategies in plants. Previous studies explained the adaptive advantages of different strategies on the basis of environmental climatic limits, but could not account for the observed co-dominance of multiple plant functional types (PFTs) in many regions. Here we used a process-based model to explore whether observed inter- and intra-PFT variation in plant traits can explain global biogeographical variation in the dominance and co-dominance of major forest types. Location World-wide. Methods We identified four important plant traits: leaf N concentration, leaf life span, fraction of net primary production (NPP) allocated to leaves and plant basal respiration rate. We incorporated means and variances of these plant traits from trait databases into the Community Atmosphere-Biosphere-Land Exchange model. We then predicted the dominant PFT or PFT mixture for global forested grid cells, using NPP as a proxy for growth rate, and considering three PFTs: evergreen needleleaf forests (ENF), evergreen broadleaf forests (EBF) and deciduous broadleaf forests (DBF). We compared results with: (1) those from simulations that did not account for trait variance; (2) results from an empirical model based purely on mean annual temperature; and (3) data from remotely sensed observations. Results Our estimates of the fractions of land area covered by major forest types were consistent with observation; i.e. ENFs dominate in boreal regions, EBFs dominate in tropical regions and DBFs are distributed widely across a broad range of environmental conditions. We also showed that co-dominance of different forest PFTs cannot be reproduced without considering variation in plant traits. Main conclusions Global trait data are useful for representing underlying plant strategies and functional diversity. Variation in key plant traits explains significant fractions of global biogeographical variation of three major forest types. Future developments in dynamic global vegetation modelling will benefit from the inclusion of plant trait variation. [ABSTRACT FROM AUTHOR]

Zonal vegetation is a large-scale expression of macro-climate and, due to the climatic diversity of the country, there are seven traditionally recognized zonal forest plant communities in Bosnia and Herzegovina. Using data from Bosnia and Herzegovina, this study aimed to reveal whether macro-climate is indeed the most important factor determining the existence of zonal forest plant communities (ZFPC). Detrended correspondence analysis of 398 relevés of seven ZFPCs revealed that the species turnover along the first axis is strongly related to the macro-climatic gradient (annual mean temperature, mean temperature of the coldest quarter and precipitation of the warmest quarter). No correlation was detected between this gradient and topographic factors (slope and aspect) and soil reaction. Floristic analysis revealed clear separation of ZFPCs in terms of diagnostic species. Functional analysis of all layers showed that competitive ecological strategy has the highest proportion, while analysis of the herb layer alone expressed a shift of CSR signatures towards the middle of the C-S axis. Ruderality was overall poorly expressed. Statistically significant differences among communities were discovered along the C-S axis. In terms of life forms, statistically significant differences in the proportions of Phanerophytes, Geophytes and Hemicryptophytes among communities were discovered. Our study confirms that macro-climatic gradient is the most important determinant of the species turnover along ZFPCs. CSR signatures show that zonal forest vegetation is represented by productive communities in a terminal stage of succession. This does not refer to degraded Quercus ilex stands (maquis), which are in the middle stage of secondary succession. [ABSTRACT FROM AUTHOR]

Cenozoic vegetation gradients in the mid- and higher latitudes of Central Eurasia are studied based on a total of 22 mega- (fruits and seeds, leaves) and 20 microfloras (pollen and spores) compiled from literature. Vegetation is interpreted at the level of plants functional types (PFTs) using a system including 26 classes and an aquatic functional type. The obtained ecospectra showing diversity of PFTs are interpreted in three time slices, namely the early Oligocene, early Miocene and late Pliocene/early Pleistocene. Our results confirm the presence of diverse mixed forests (Turgai type) in the study area throughout the late Paleogene and early Neogene, partly, raised diversity of herbaceous components, especially of dry herbs, and the presence of xeric shrub PFTs points to more open plant cover. The late Pliocene/early Pleistocene spectra from the central and southern latitudinal zones of the study area confirm the existence of open landscapes in general, but partly have a considerable arboreal diversity excluding the presence of mere steppe. Ecospectra obtained from the diversity of functional types have a characteristic representativeness depending on the organ types considered in each case, and therefore have a delimited comparability. Our results show that PFT diversities obtained from microfloras are most suitable in estimating the openness of landscape and in representing zonal biomes in general. The vegetational patterns reconstructed based on the ecospectra of fossil floras basically support the results obtained from previous palaeoclimate reconstructions evidencing cooling and drying of the continental interior of Eurasia throughout the later Neogene. Moreover, the PFT approach is proven more sensitive to identify seasonal drought when compared to other, taxonomy based climate reconstruction methods. Moreover, a first attempt is made to quantify latitudinal temperature gradients for the study area. Data indicate that the Oligocene and early Miocene gradients where shallow and almost identical while the late Pliocene/early Pleistocene gradient was intermediate between the earlier Neogene and the modern one. [ABSTRACT FROM AUTHOR]

The Pannonian Basin system provides sufficient data to study local and regional vegetation in the context of palaeoclimate and palaeogeography. The present study attempts to make use of the latest results in stratigraphy and track vegetation change throughout the Late Miocene. Vegetation layers are reconstructed for five time slices, from 10.8 Ma to 6.5 Ma, and placed in a palaeogeographic context. Plant functional types and their distribution, frequently applied in ecological studies and biome modelling, serve as a tool for reconstructing palaeovegetation units. A classification system is introduced considering non-zonal elements as well, in order to represent the Neogene floral record. The PFT spectra obtained from fossil leaf assemblages indicate the presence of mainly broadleaved deciduous vegetation throughout the regarded time span, with variable diversities of conifers and broadleaved evergreen vegetation components. During the Late Miocene, the lowland vegetation of the Pannonian realm seemed to be more homogeneous than reported in other reconstructions, which is in line with the persistence of overall warm and humid climate conditions. The existence of distinctly dry periods as partly suggested by other proxies is not supported. At the same time, data suggest the coeval declining trend of the broadleaved evergreen component in the study area, and its final complete disappearance from the north of the Pannonian Basin. In the younger time slices, constantly humid conditions might have existed along the northern border of the lake, possibly connected to uplift pulses of the Alps and Carpathians. [ABSTRACT FROM AUTHOR]

Many drylands, including the south-western United States, are projected to become more water-limited as these regions become warmer and drier with climate change. Such chronic drought may push individual species or plant functional types beyond key thresholds leading to reduced growth or even mortality. Indeed, recent observational and experimental evidence from the Colorado Plateau suggests that C3 grasses are the most vulnerable to chronic drought, while C4 grasses and C3 shrubs appear to have greater resistance., The effects of chronic, or press-drought are predicted to begin at the physiological level and translate up to higher hierarchical levels. To date, the drought resistance of C4 grasses and C3 shrubs in this region has been only evaluated at the community level and thus we lack information on whether there are sensitivities to drought at lower hierarchical levels. In this study, we tested the apparent drought resistance of three dominant species ( Pleuraphis jamesii, a C4 rhizomatous grass; Coleogyne ramosissima, a C3 drought-deciduous shrub; and Ephedra viridis, a C3 evergreen shrub) to an ongoing experimental press-drought (-35% precipitation) by comparing individual-level responses (ecophysiology and growth dynamics) to community-level responses (plant cover)., For all three species, we observed consistent responses across all hierarchical levels: P. jamesii was sensitive to drought across all measured variables, while the shrubs C. ramosissima and E. viridis had little to no responses to the experimental press-drought at any given level., Synthesis. Our findings suggest that the apparent drought resistance at higher hierarchical levels, such as cover, may serve as good proxies for lower-level responses. Furthermore, it appears the shrubs are avoiding drought, possibly by utilizing moisture at deeper soil layers, while the grasses are limited to shallower layers and must endure the drought conditions. Give this differential sensitivity to drought, a future with less precipitation and higher temperatures may increase the dominance of shrubs on the Colorado Plateau, as grasses succumb to chronic water stress. [ABSTRACT FROM AUTHOR]

Este estudo teve como objetivo avaliar, no outono, as características morfogênicas de oito gramíneas nativas da região central do Rio Grande do Sul, classificadas sob uma tipologia funcional, segundo o teor de matéria seca e a área foliar específica em A, B, C, D: Axonopus affinis (A), Andropogon lateralis (B), Paspalum notatum (B), Paspalum plicatulum (C), Piptochaetium montevidense (C) Aristida laevis (D), Saccharum angustifolius (D) e Sorghastrum pellitum (D); submetidas a dois níveis de nitrogênio (zero e 200kg ha-1 de N). O delineamento experimental foi o inteiramente casualizado com arranjo fatorial 8 (espécies) x 2 (níveis de N) ou 4 (tipos funcionais) x 2 (níveis de N), ambos com três repetições. As plantas foram submetidas a cortes segundo diferentes durações de elongação foliar, definidas por médias das espécies por tipo funcional. As variáveis foram analisadas estatisticamente usando testes de aleatorização com o software MULTIV. Não houve diferença significativa entre os níveis de N, porém houve entre as espécies e entre os tipos funcionais. As variáveis morfogênicas são coerentes com a tipologia funcional utilizada como referência, baseada em atributos foliares. Os níveis de nitrogênio não alteram a morfogênese das espécies na estação do outono, sendo seu uso desaconselhado nesse período.The morphogenetic characteristics of eight native grasses of South Brazil were evaluated during autumn. They were classified in a functional typology, according to dry matter content and specific leaf area (A, B, C, D): Axonopus affinis (A), Andropogon lateralis (B), Paspalum notatum (B), Paspalum plicatulum (C), Piptochaetium montevidense (C) Aristida laevis (D), Saccharum angustifolius (D) and Sorghastrum pellitum (D), under two nitrogen (N) fertilization levels (zero and 200kg ha-1 N). Experimental design was completely randomized in a factorial arrangement: eight (species) x two (N levels) with three replicates or four (functional types) x two (N levels) both with three replicates. Plants were submitted to cuts according to different leaf lamina elongation, defined by means of species classified by functional type. The variables were statistically analyzed using randomization tests with software MULTIV. There was no significant difference between N levels, but there was among species and among functional types. Morphogenic variables are consistent according to the functional typology used as reference, based on leaf traits. Nitrogen fertilization does not change morphogenetic characteristics of evaluated species during autumn, and its use is discouraged during this season.

This article is a Commentary on Rosas et al. 223: 632–646. [ABSTRACT FROM AUTHOR]

Land surface temperature over the past decades has shown a faster warming trend during the night than during the day. Extremely low night temperatures have occurred frequently due to the influence of land-sea thermal difference, topography and climate change. This asymmetric night temperature change is expected to affect plant ecophysiology and growth, as the plant carbon consumption processes could be affected more than the assimilation processes because photosynthesis in most plants occurs during the daytime whereas plant respiration occurs throughout the day. The effects of high night temperature (HNT) and low night temperature (LNT) on plant ecophysiological and growing processes and how the effects vary among different plant functional types (PFTs) have not been analyzed extensively. In this meta-analysis, we examined the effect of HNT and LNT on plant physiology and growth across different PFTs and experimental settings. Plant species were grouped according to their photosynthetic pathways (C3, C4 and CAM), growth forms (herbaceous, woody), and economic purposes (crop, non-crop). We found that HNT and LNT both had a negative effect on plant yield, but the effect of HNT on plant yield was primarily related to a reduction in biomass allocation to reproduction organs and the effect of LNT on plant yield was more related to a negative effect on total biomass. Leaf growth was stimulated at HNT and suppressed at LNT. HNT accelerated plants ecophysiological processes, including photosynthesis and dark respiration, while LNT slowed these processes. Overall, the results showed that the effects of night temperature on plant physiology and growth varied between HNT and LNT, among the response variables and PFTs, and depended on the magnitude of temperature change and experimental design. These findings suggest complexities and challenges in seeking general patterns of terrestrial plant growth in HNT and LNT. The PFT specific responses of plants are critical for obtaining credible predictions of the changes in crop production, plant community structure, vegetation dynamics, biodiversity, and ecosystem functioning of terrestrial biomes when asymmetric night temperature change continues.

Imidazolinones and crops resistant to these herbicides have successfully been introduced recently in some European countries. Imazamox has a high efficacy, moderate persistence and ecotoxicity, but data on hazardous doses (HD) in non-target plants and species sensitivity distributions (SSDs) are still scarce. To screen a larger variety of plant taxa in standardized vegetative vigor tests, 22 wild plant species and 14 oilseed rape (OSR) cultivars were sown into trays filled with a standard soil. When seedlings had reached the three-to-four leaf stage, plants were exposed to a single application of the herbicide Bolero® using a commercial pump sprayer. The five treatments corresponded to rates of 0 (control), 0.4, 4, 20 and 40 g/ha of imazamox with latter representing the recommended dose in Switzerland. Two weeks after the application, five plants per treatment were sub-sampled at random and visible injuries and fresh weights were recorded as endpoints for herbicidal effects. Dose-response curves and effective doses (EDs) were fitted using the drc package of the statistical software R and SSDs were obtained using ETX2.0. ED50 varied between 0.006 and 37 g/ha of the active ingredient in Nigella arvensis and Brassica rapa. Several dose-response curves indicated hormetic effects at a hundredth of the recommended field dose. In OSR, exposure to the field rate (40 g/ha) resulted in growth reductions between 28 and 97 % in the non imazamox-tolerant cultivars and in growth stimulations of up to 20 % in imazamox-tolerant cultivars. Responses were unrelated to leaf thickness, growth rates and the taxonomy of the tested species. Hazardous doses were 0.32 g/ha for HD5 and 3.9 g/ha for HD50 indicating that 50 % of the non-target plants would be affected at a tenth of the recommended dose. Based on general herbicide drift values the results suggest that potentially adverse effects may be expected up to a distance of 4 m offsite.