Specific Leaf Area Values Research Articles

Funtional Ecology of fronds in Iberian saxicolous ferns

Nowadays, functional traits are widely used to study autoecological aspects in plant species. The analysis of these traits among climatic gradients allows us to know the strategy that plants follow depending on resource availability. Referring to plants, the traits measured in the leaves have a special importance; among these traits we can find SLA (Specific Leaf Area), LDMC (Leaf Dry- Matter Content) and LT (Leaf Thickness). In this work, these traits are measured in four species of the genus Asplenium. As extremes of a climatic gradient, we have focused our study in both bioclimatic regions existing in the Iberian Peninsula. Taking into account the differences referring to the resource availability for the species in each region, the main goal of this work is analyzing the variations of the three functional traits mentioned in the four species in both locations and associate these variations to macroclimatic variables. To this aim, fronds from the four species were collected in populations of each bioclimatic region to determine the fresh weight, dry weight and the foliar area. From these variables, we calculated the three functional traits. The results have shown that ferns adopt higher productive yields in the Mediterranean region (higher SLA values) and lower LDMC and LT values than in the Eurosiberian region. As to the climate variables effects, the average of the maximum temperatures in the warmest month (TMAX) is the variable that better explains the differences in the productive yield that the plants adopt in each region. On the other hand, annual precipitation seems not to play an important role on any of the functional traits in any of the species. Finally, we didn’t find a generalized tendency in the effects of the extern variables: frozen period, minimum temperatures in the coolest month and arid period.

Functional ecology and imperfect detection of species

Abstract Functional traits are increasingly being used to understand the response of species to environmental change and their effects on ecosystem functioning. However, some ecologically important traits, such as plant height, influence the probability of species detection during field surveys. Imperfect detection of species could therefore bias measures of functional trait composition and diversity, leading to incorrect estimates of trait–environment relationships due to a process of “detection filtering.” The importance of detection filtering for functional ecological studies remains unknown. We used hierarchical models that account for detection filtering to analyse data on 1,296 vascular plant species sampled in 362 1‐km2 plots, distributed along a 2,460‐m elevational gradient in Central Europe. We examined how detection filtering altered measures of functional diversity (multivariate functional richness and packing) and composition (community means of three traits). We also determined whether the strength of detection filtering varied over the gradient, to determine whether detection filtering biased trait–environment relationships. Species detectability was correlated with all three functional traits tested in this study, meaning that short species with small seeds and high specific leaf area values were less likely to be detected. This suggests that imperfect detection has the potential to bias measures of functional composition. Generally, measures of functional composition were not strongly affected by detection filtering, but functional packing was underestimated when detection filtering was not accounted for. In addition to the traits, distributional characteristics were important; rare species and species occurring mainly at low elevations tended to have lower detection probabilities. Overall, detection filtering did not strongly bias trait–environment relationships because the effects of the environment on functional composition and diversity were larger than the effects of detection. Our results suggest that many measures of functional composition and diversity are robust to detection filtering, but some are likely biased. Functional ecologists should consider correcting for imperfect detection, and our approach provides a simple method to do so for a wide range of datasets.

Environmental filtering drives community specific leaf area in Spanish forests and predicts relevant changes under future climatic conditions

Abstract How functional traits at community level relate with environmental conditions is of great relevance to assess potential effects of climate change on ecosystem functioning. Species’ specific leaf area (SLA) is well recognised to be closely correlated with species drought resistance and with other forest functions such as productivity. Here, we used tree species abundance data from 44 501 forest plots from the Third Spanish National Forest Inventory and species SLA values from literature to assess how community weighted mean SLA (CWM SLA ) and SLA diversity within communities (FDis SLA ) of Spanish forests correlate with aridity. Later, using 19 climate change projections and following an approach that limits the values of CWM SLA along an aridity gradient, we assessed the potential climatic effects on CWM SLA for 2050 under the representative concentration pathways (RCP) 4.5 and 8.5. Results showed that CWM SLA and FDis SLA decreased significantly with aridity (deviance explained was 22 and 9%, respectively) suggesting an effect of climatic filtering at community level constraining the diversity of co-occurring strategies at harsher conditions. Up to 25% of plots were predicted to suffer changes in CWM SLA with these impacts being more common and of a greater magnitude in communities characterised by a high CWM SLA and located at humid and mid-altitude zones. Instead, communities already striving in arid areas appeared to be more resilient. The study proves useful for orienting forest management practices in current permanent forest stands based on trait ecology (e.g. promoting communities species composition with specific trait values), to increase their mitigation potential and adaptive capacity to current and future changing climate conditions.

Disturbance, Trait Similarities, and Trait Advantages Facilitate the Invasion Success of Alternanthera philoxeroides (Mart.) Griseb.

Riparian wetlands suffer serious plant invasion. Natural habitats and disturbance are two prominent environmental factors affecting the invasion process of exotic riparian invaders. In this study, a noxious invasive riparian plant, Alternanthera philoxeroides, and its native congener, Alternanthera sessilis were cultivated in three different riparian soils with different statuses of disturbance by cow manure addition. After harvest, we measured plant morphological traits including the internode length (INL), rooted node number (RNN), specific leaf area (SLA) and leaf mass ratio (LMR), and physiological traits including the maximal quantum yield (Fv/Fm), chlorophyll content (Ct), leaf nitrogen content (Nmass), leaf carbon/nitrogen ratio (C/N ratio), leaf construction cost per leaf area (CCarea), and non‐structural carbohydrate content (NSCC). Fertilization was found to improve the performances of most traits for both species similarly. Both species shared some similarities in trait values of SLA, LMR, CCarea and NSCC, and trait plasticity in NSCC in unfertilized sediments and SLA, LMR, C/N ratio, and CCarea in fertilized sediments. Moreover, compared to A. sessilis, A. philoxeroides showed some advantages in trait values of RNN in unfertilized sediments and Ct, Nmass, and C/N ratio in the most fertile treatments, and trait plasticity in INL, RNN, SLA, Ct, Nmass, and CCarea across different sediments. In conclusion, the disturbance, trait similarities, and trait advantages likely promote the invasion success of A. philoxeroides.

Size and Reproductive Traits Rather than Leaf Economic Traits Explain Plant-Community Composition in Species-Rich Annual Vegetation along a Gradient of Land Use Intensity.

Agricultural land use imposes a major disturbance on ecosystems worldwide, thus greatly modifying the taxonomic and functional composition of plant communities. However, mechanisms of community assembly, as assessed by plant functional traits, are not well known for dryland ecosystems under agricultural disturbance. Here we investigated trait responses to disturbance intensity and availability of resources to identify the main drivers of changes in composition of semiarid communities under diverging land use intensities. The eastern Mediterranean study region is characterized by an extended rainless season and by very diverse, mostly annual communities. At 24 truly replicated sites, we recorded the frequency of 241 species and the functional traits of the 53 most common species, together with soil resources and disturbance intensity across a land use gradient ranging from ungrazed shrubland to intensively managed cropland (six land use types). Multivariate RLQ analysis (linking functional traits, sites and environmental factors in a three-way ordination) and fourth corner analysis (revealing significant relations between traits and environmental factors) were used in a complementary way to get insights into trait-environment relations. Results revealed that traits related to plant size (reflecting light absorption and competitive ability) increased with resource availability, such as soil phosphorus and water holding capacity. Leaf economic traits, such as specific leaf area (SLA), leaf nitrogen content (LNC), and leaf dry matter content showed low variation across the disturbance gradient and were not related to environmental variables. In these herbaceous annual communities where plants grow and persist for just 3–5 months, SLA and LNC were unrelated, which together with relatively high SLA values might point to strategies of drought escape and grazing avoidance. Seed mass was high both at higher and lower resource availability, whereas seed number increased with the degree of disturbance. The strong response of size and reproduction traits, and the missing response of leaf economic traits reveal light interception and resource competition rather than resource acquisition and litter decomposition as drivers of plant community composition. Deviations from trait relationships observed in commonly studied temperate ecosystems confirm that climatic conditions play a fundamental role by filtering species with particular life forms and ecological strategies.

Context-dependent variation of SLA and plant height of a dominant, invasive tall grass (Brachypodium genuense) in sub-Mediterranean grasslands

The cessation of semi-extensive farming and the abandonment of settlements are threatening European pastoral landscapes and their biodiversity, affecting species assemblage and ecosystem functioning. This process typically involves invasion by coarse tall grasses, mostly with competitive stress-tolerant strategies, and rapid development of mono-dominance stands. A key species in this respect is Brachypodium genuense (DC.) Roem. et Schult., an endemic, rhizomatous, tall-grass that grows in the semi-natural grasslands of the Italian peninsula over 1200–1400m a.s.l.We hypothesized that B. genuense was able to spread and dominate the grassland communities subjected to a wide range of environmental conditions through its broad spectrum of performances. In fact, it has considerable morphological variability, mirrored by high variations of traits, namely Specific Leaf Area (SLA), individual height, and tussock cover values. The study area encompassed the Monti Sibillini National Park (central Italy). We found that in more productive conditions (deeper soil, medium/high pH values, north-facing slopes, and “conservative” landforms) populations of B. genuense had higher SLA, plant height and cover values than in low productive conditions (south-facing slopes, shallow soils, lower pH values). This indicates a fast-growing strategy based on a high rate of resource acquisition and use, as well as high competitive ability for aboveground resources such as light under productive conditions. Under unproductive and/or dry conditions decreased SLA, plant height and cover value indicate a slow-growing strategy with high conservation and low rate of resource acquisition. In addition, we found that a very high amount of nitrogen in the soil might have a detrimental effect on B. genuense individuals, decreasing the SLA values, thus requiring the plant to change its growth strategy. Finally, we inferred that the observed variability in SLA might have a paramount role in the invasive/dominant behavior of Brachypodium genuense.

Variation in leaf functional traits of different-aged Robinia pseudoacacia communities and relationships with soil nutrients

On the basis of various leaf functional traits of different-aged Robinia pseudoacacia communities, as well as the relationships between the traits and soil nutrients, the adaptation strategy of R. pseudoacacia in relation to soil conditions was analyzed in Ansai County, the Loess Plateau, China. The results showed that specific leaf area, leaf area, leaf water content, leaf total nitrogen content and leaf organic carbon content first increased and then decreased with the increasing stand age. The peak values of specific leaf area (279.18 cm2·g-1), leaf area (12.33 cm2), leaf water content (0.09%), leaf total nitrogen content (33.01 g·kg-1) and leaf organic carbon content (523.08 g·kg-1) were obtained at 30 years old. With the increasing stand age, leaf tissue density, leaf total phosphorus content, leaf thickness and stomata density increased, and stomata length and stomata width decreased. Leaf area, specific leaf area, leaf total phosphorus content, leaf water content, leaf thicknessand stomata density were the main indexes based on principal component analysis (PCA), for R. pseudoacacia leaf functional traits responding to the increased stand age. The indexes were correlated with each other, indicating that R. pseudoacacia was capable of changing leaf morphological structure to adapt to environmental changes. Soil total nitrogen content was the main factor influencing leaf area, leaf water content, specific leaf area and stomata length, while soil organic carbon content mainly affected stomata width, leaf tissue density, leaf thickness, leaf total phosphorus content, leaf total nitrogen content and stomata density. Therefore, soil total nitrogen and organic carbon content were main factors that affected leaf functional traits of R. pseu-doacacia in different stand ages. Soil nutrients in R. pseudoacacia communities were improved with the increasing stand age, which eventually affected leaf functional traits. The flexibility of leaf functional traits indicated that R. pseudoacacia communities had great potential to adapt to environmental change in Loess Plateau hilly region.

Community aggregated traits disclose functional responses to seasonal resource fluctuations and spatial heterogeneity

Aim To investigate changes in community-level functional responses to rainfall seasonality in Neotropical grasslands through the analysis of community aggregated traits. Location Semi-natural grasslands in the Rio Grande de Matagalpa watershed, Nicaragua. Methods We measured 14 functional response traits that are indicators of plant resource-use strategies, across 32 herbaceous and four woody species in eight permanent plots: leaf size, specific leaf area, leaf dry matter content, leaf lifespan, foliar concentrations of P, N, Ca, K and Mg, plant height, lateral spread by clonal growth, root depth, start of flowering period and length of the period from flowering to seed shed. We calculated the community-weighted means (CWM) with trait values weighted by species cover for five different paddocks 11 times (between 2 Jul 2007 and 26 May 2008), and grouped them into four periods according to rainfall seasonality: early rainy season, late rainy season, early dry season and late dry season. Results Community aggregated values of specific leaf area, leaf dry matter content, leaf lifespan, foliar concentrations of P, N, Ca, K and Mg, length of the period from flowering to seed shed, and to a lesser extent lateral spread by clonal growth responded to temporal variations in rainfall, and corresponded to a considerable extent to expectations based on plant resource-use strategies along resource supply gradients. Community aggregated values of specific leaf area and foliar nutrient concentration were higher in the rainy season than in the dry season, while we observed an opposite trend with leaf dry matter content and leaf lifespan. Conclusions Semi-natural grasslands of central Nicaragua experience shifts in plant trait dominance that correspond with changes in resource supply given by rainfall seasonality, indicating that the stabilizing function of net primary productivity found in earlier studies can in part be a consequence of temporal differentiation in functional responses.

Community-level relaxation of plant defenses against herbivores at high elevation

Ecological gradients shape the evolution of plant functional traits through variation in climate, abiotic factors, and biological processes. While recent observations highlight elevation clines in functional trait variation, several traits vary independently of others and vary in species-specific manner, thereby hindering community-level generalization. In this study, we examined whether whole plant communities at different elevations independently converge to elevation-specific trait values. Using a combination of field-derived trait quantification and a literature survey, we analyzed eight functional traits relating to plant palatability [specific leaf area (SLA), leaf dry matter content, carbon-to-nitrogen ratio], and defenses (spines, trichomes, silica, and the relative importance of phenolic- or non-phenolic-based chemical defenses in plants) of plants growing along several mountain transects in Switzerland, and computed community-level means for each trait. We observed a general decline of most defense traits in communities at high elevations. The individual traits’ patterns underlined a concerted decline of the physico-chemical defense syndrome at high elevation, and low SLA values at high elevation also indicate investment in the production of leaves with slow turnover rates. In addition, we found that high-elevation plant trait values tend to converge, while at low elevation, to diverge within communities. Our data suggest that community-level defense syndromes along elevation gradients are influenced by ecological filtering. Lower herbivore pressures select for reduced plant defenses, while harsh environmental conditions select for investment in tolerance-related traits. Secondly, since species are highly variable in their functional trait space within communities, niche-partitioning theory might explain which variabilities of the defense functional space are selected within communities, particularly at low elevation.

COMUNICACIÓN Morfometría foliar y clorofila de Piper reticulatum (Piperaceae) en luz y sombra en la Estación Biológica La Selva, Costa Rica

Las plantas tropicales presentan gran variedad en su morfología y fisiología para captar luz dentro del bosque. Piper reticulatum es un pequeño árbol con la capacidad vivir en condicionesde luz y sombra. En este trabajo se comparó algunos parámetros foliares en condicionesde luz y sombra en P. reticulatum. Se tomaron 50 hojas maduras al azar de diferentes individuos, 25 por cada tipo de hábitat, a cada una se le determinó el área foliar específica, grosor, forma de la hoja y cantidad de clorofila. Se determinó que existe diferencia significativa entre las plantas a la luz y a la sombra en el área foliar específica, grosor, forma y cantidad de clorofila de la hoja. Las plantas a la luz presentaron valores más altos en la forma de la hoja y grosor y las plantas a la sombra presentaron valores más altos de área foliar específica y clorofila. Los resultados indican que P. reticulatum presenta una gran plasticidad en cuanto a la forma de las hojas lo cual mejora su rendimiento y le permite competir mejor con otras especies.

Seeded pioneer die-offs reduce the functional trait space of new-growth coastal dune forests

The planting or seeding of pioneer species to promote restoration apparently contributes little to the establishment of late-successional species, despite the common assumption that they facilitate forest regeneration. We evaluate the consequences of planting pioneers for coastal dune restoration by measuring plant traits (specific leaf area, wood density, δ13C and maximum plant height), species composition and canopy openness in three rehabilitating forests of different ages, where a pioneer species (Acacia karroo) was seeded, and one undisturbed old-growth forest. We surveyed woody species composition in 2010 and in 2015 to assess how changes in A. karroo influences community structure of rehabilitating forest. Our results showed that the number of adult individuals of A. karroo decreased progressively with forest age, indicating that the demise of individuals of A. karroo opens canopy gaps in rehabilitating sites. This accorded with a significantly higher variation of canopy openness levels in the oldest rehabilitating site. Rehabilitating sites tended to progress towards a reduced trait space as they aged, contrasting with the old-growth forest that showed an expanded trait space. Communities located at high levels of canopy openness were dominated by species with lower values of specific leaf area and wood density, indicative of acclimation to high light conditions and fast-growing strategies. Our results suggest that changes in light availability due to canopy gap formation, can act as an environmental filter which may deflect forest regeneration trajectories. We show that coupling a trait-based approach with environmental measurements can give insight in regeneration trajectories of rehabilitating sites and, therefore, better inform restoration practices. Preventing the formation of large canopy gaps in restoration programs using pioneers as a regeneration pathway may facilitate the natural recovery of degraded forest.

Physiological plasticity of main tree species of lowland hornbeamoak forest as a results of forest gap regeneration

Specific leaf area (SLA) of English oak (Quercus robur L.) and hornbeam (Carpinus betulus L.) as members of Querco robori-Carpinetum were investigated in two different habitat in terms of gap forest management: in the gap and in the inert forest. The artificial opening process of the forest resulted in more light for growing saplings and need for acclimatization. Photosynthesis is one of the most important ways for plant life and plant production basically influenced by altered light condition resulted in opening process. Efficient photosynthesis is important for plant life, plant production, but species-dependent plasticity of photosynthesis makes one species more tolerant, than others. The specific leaf area is acceptable parameters for characterising plant production, dry matter content and leaf structure. The dry matter content based on known leaf area is higher in oak both sun and shade leaves, than hornbeam. The different place of leaves in the canopy of trees did not influence the values of SLA.

Specific leaf area and leaf area index in developing stands of Fagus sylvatica L. and Picea abies Karst.

European beech (Fagus sylvatica L.) and Norway spruce (Picea abies Karst.) are two of the most ecologically and economically important forest tree species in Europe. These two species co-occur in many locations in Europe, leading to direct competition for canopy space. Foliage characteristics of two naturally regenerated pure stands of beech and spruce with fully closed canopies were contrasted to assess the dynamic relationship between foliage adaptability to shading, stand LAI and tree growth. We found that individual leaf size is far more conservative in spruce than in beech. Individual leaf and needle area was larger at the top than at the bottom of the canopy in both species. Inverse relationship was found for specific leaf area (SLA), highest SLA values were found at lowest light availability under the canopy. There was no difference in leaf area index (LAI) between the two stands, however LAI increased from 10.8 to 14.6m2m−2 between 2009 and 2011. Dominant trees of both species were more efficient in converting foliage mass or area to produce stem biomass, although this relationship changed with age and was species-specific. Overall, we found larger foliage plasticity in beech than in spruce in relation to light conditions, indicating larger capacity to exploit niche openings.

气孔特征与叶片功能性状之间关联性沿海拔梯度的变化规律：以长白山为例

PDF HTML阅读 XML下载 导出引用 引用提醒 气孔特征与叶片功能性状之间关联性沿海拔梯度的变化规律——以长白山为例 DOI: 10.5846/stxb201411042162 作者: 作者单位: 中国科学院地理科学与资源研究所,中国科学院地理科学与资源研究所,中国科学院地理科学与资源研究所,中国科学院地理科学与资源研究所,中国科学院地理科学与资源研究所,中国科学院地理科学与资源研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金重大项目(31290221); 中国科学院地理科学与资源研究所可桢杰出青年学者计划(2013RC102) Altitudinal variation in the covariation of stomatal traits with leaf functional traits in Changbai Mountain Author: Affiliation: Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences,,Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:气孔是陆生植物与外界环境进行水分和气体交换的主要通道,控制着植物的光合作用和蒸腾过程。植物往往通过多种性状的组合来适应变化的环境,叶片功能性状之间的紧密关系已经在不同尺度得到证实。然而,植物气孔特征与叶片其它功能性状是否存在关联性以及这种关联性是否会受到环境变化梯度的影响仍鲜少报道。沿长白山北坡6个海拔梯度,测定了150种植物的气孔特征和叶片功能性状。结果发现,气孔密度(SD)与比叶面积(SLA)负相关,与单位面积的叶氮含量(Narea)正相关;除了SLA和Narea外,气孔长度(SL)与SLA、叶片厚度(LT)和单位质量的叶氮含量(Nmass)均存在显著的相关性(P < 0.05)。然而,气孔特征与叶片功能性状的相关性只在部分海拔梯度存在。此外,发现SD与SL之间存在稳定一致的负相关关系。这些结果表明,植物气孔特征与叶片形态和化学特征对环境变化的适应存在一定的协同变异性,但这种关系不具有普适性,主要与气孔特征和叶片功能性状的选择压力存在差异以及物种分布范围相关。未来仍需要在更多物种和不同区域内来验证气孔特征与植物功能性状之间的关联关系。 Abstract:Stomata, small pores on the surfaces of plant leaves and stalks, act as turgor-operated valves to control gas (e.g. water vapor and carbon dioxide) exchange between plant tissues and the atmosphere. Stomata therefore play a major role in the regulation of water and carbon cycling. Generally, plants adapt to changing environments through the combination of multiple traits. The strong relationships between leaf morphological, chemical, and physiological traits have been documented within and across plant species, biomes, and even globally. Despite the importance of leaf stomata, little is known about interspecific covariation in stomatal traits and their relations with other leaf functional traits on a large scale, partly due to a lack of data on leaf stomata in most studies. In the present study, we measured stomatal and leaf functional traits, including stomatal density (SD), stomatal length (SL), specific leaf area (SLA), leaf area (LA), leaf thickness (LT), and nitrogen content (mass- and area-based, Nmass and Narea) of 150 plant species along an altitudinal gradient (540-2357 m) in Changbai Mountain, China. Our results showed that, for all species, the average values of SD and SL were 155.91 stomata/mm2 and 34.51 μm, respectively; the average values of SLA, LA, and LT were 33.58 m2/kg, 3291.30 mm2, and 0.14 mm, respectively; the mean values of Nmass and Narea were 24.48 g/kg and 1.07 g/m2. There were significant relationships between stomatal traits and other leaf functional traits (P < 0.05). Specifically, SD was negatively correlated with SLA, and positively correlated with Narea (P < 0.05); SL was negatively correlated with LA and Nmass, and positively correlated with LT (all P < 0.05). Additionally, SL was negatively correlated with SD (P < 0.05). Standardized major axis (SMA) analysis showed that these significant relationships between stomatal traits and morphological and chemical traits of leaves differed among different altitudes. However, the strong relationship between SD and SL was observed at all altitudes. Furthermore, although no significant difference (P > 0.05) was found among these slopes of SD-SL relationships, the y-intercepts differed significantly (P < 0.05), in which the maximum occurred at 1286 m, and the minimum at 2357 m, indicating plants with larger stomata (higher SL) at any given SD occurred at 1286 m than those with smaller stomata (lower SL) at 2357 m. These findings suggest that there is a covariation between stomatal traits and leaf morphological and chemical traits. However, this may not be universal for all plants due to different stress responses between stomata and other leaf structures. Moreover, the narrow taxonomic range at each altitude may also restrict the expression of bivariate relationships. Future research needs to verify the relationships between stomatal traits and plant functional traits in more plant species from different areas. Finally, our findings highlight the trade-off between SD and SL, which regulates the short-term (plastic) and long-term (evolutionary) strategies in plant adaptation to the external environment. These data provide a basis for revealing adaptation strategies in plants, and help us predict their responses to future climate changes. 参考文献 相似文献 引证文献

Specific leaf area correlates with temperature: new evidence of trait variation at the population, species and community levels

Although specific leaf area (SLA) has been proposed to reflect plant responses to climatic changes, the link between SLA and temperature has never been systematically evaluated. Using in situ measured SLA values for 223 species occurring in 29 calcareous grasslands along a temperature gradient in the Bavarian Alps, we explored the SLA–temperature relationship at population (intraspecific), species (interspecific) and community level and investigated the relative impact of other environmental factors on SLA variation along the temperature gradient at the community level. Only 14 % of the studied species showed significant changes in their SLA values along the temperature gradient, despite high intraspecific variability of the SLA values. At the species level, we revealed a very weak positive SLA–temperature relationship (r2 = 0.04, p < 0.001). A very strong positive correlation between SLA and temperature was detected at the community level (r2 = 0.70, p < 0.001). In addition to temperature, disturbance also had a significant influence on trait variation at the community level. We conclude that the variation in SLA along the temperature gradient comes primarily from changes in the relative abundances of species, whereas the trait variation at the population and the species levels was affected by other environmental factors. We therefore recommend the use of community-weighted mean values in studies employing SLA–temperature relationships because they reveal more regular patterns than the underlying distribution of within- and among-site SLA values.

Ecological strategies of Al-accumulating and non-accumulating functional groups from the cerrado sensu stricto.

The cerrado's flora comprises aluminum-(Al) accumulating and non-accumulating plants, which coexist on acidic and Al-rich soils with low fertility. Despite their existence, the ecological importance or biological strategies of these functional groups have been little explored. We evaluated the leaf flushing patterns of both groups throughout a year; leaf concentrations of N, P, K, Ca, Mg, S, Al, total flavonoids and polyphenols; as well as the specific leaf area (SLA) on young and mature leaves within and between the groups. In Al-accumulating plants, leaf flushed throughout the year, mainly in May and September; for non-accumulating plants, leaf flushing peaked at the dry-wet seasons transition. However, these behaviors could not be associated with strategies for building up concentrations of defense compounds in leaves of any functional groups. Al-accumulating plants showed low leaf nutrient concentrations, while non-accumulating plants accumulated more macronutrients and produced leaves with high SLA since the juvenile leaf phase. This demonstrates that the increase in SLA is slower in Al-accumulating plants that are likely to achieve SLA values comparable to the rest of the plant community only in the wet season, when sunlight capture is important for the growth of new branches.

Predicting climate change effects on wetland ecosystem services using species distribution modeling and plant functional traits.

Wetlands provide multiple ecosystem services, the sustainable use of which requires knowledge of the underlying ecological mechanisms. Functional traits, particularly the community-weighted mean trait (CWMT), provide a strong link between species communities and ecosystem functioning. We here combine species distribution modeling and plant functional traits to estimate the direction of change of ecosystem processes under climate change. We model changes in CWMT values for traits relevant to three key services, focusing on the regional species pool in the Norrström area (central Sweden) and three main wetland types. Our method predicts proportional shifts toward faster growing, more productive and taller species, which tend to increase CWMT values of specific leaf area and canopy height, whereas changes in root depth vary. The predicted changes in CWMT values suggest a potential increase in flood attenuation services, a potential increase in short (but not long)-term nutrient retention, and ambiguous outcomes for carbon sequestration.Electronic supplementary materialThe online version of this article (doi:10.1007/s13280-014-0593-9) contains supplementary material, which is available to authorized users.

Similar foliage area but contrasting foliage biomass between young beech and spruce stands / Porovnateľná plocha avšak kontrastná biomasa asimilačných orgánov medzi mladými porastmi buka a smreka

Abstract The study focuses on two young stands of European beech (Fagus sylvatica) and Norway spruce (Picea abies) of the same age (12-yearold) with similar sized trees grown at near identical sites. After performing a destructive sampling technique which included all tree compartments except fine roots; allometric equations were constructed for all tree components. Diameter at stem base (do) was utilized as an independent variable for the equations. The models expressed not only biomass of woody parts (branches, stem and coarse roots) and foliage but also foliage area and specific leaf area (SLA). Results indicate that the basic morphological properties of foliage vary in both species along the vertical crown profile. In spruce, contrasting values of needle area and SLA were recorded among needle sets (based on year of establishment). On a tree level, both spruce and beech had similar foliage areas however, beech had a larger biomass comprising of woody parts while spruce biomass was dominated by foliage. Therefore the leaf mass ratio (LMR) defined as the ratio between foliage biomass and total tree biomass, as well as leaf area ratio (LAR) defined as the ratio between leaf area and total tree biomass were much larger in spruce than in beech species. On a stand level, spruce manifested a higher value (18.64 m2.m−2) of leaf area index (LAI) than beech (12.77 m2.m−2). Moreover, while the biomass of foliage was 4.6 times higher in spruce than in beech, total biomass of woody parts were similar in both stands. These contrasts indicate very different growth strategies and biomass allocations between beech and spruce at the young growth stages

Plant communities on infertile soils are less sensitive to climate change.

Much evidence suggests that plant communities on infertile soils are relatively insensitive to increased water deficit caused by increasing temperature and/or decreasing precipitation. However, a multi-decadal study of community change in the western USA does not support this conclusion. This paper tests explanations related to macroclimatic differences, overstorey effects on microclimate, variation in soil texture and plant functional traits. A re-analysis was undertaken of the changes in the multi-decadal study, which concerned forest understorey communities on infertile (serpentine) and fertile soils in an aridifying climate (southern Oregan) from 1949-1951 to 2007-2008. Macroclimatic variables, overstorey cover and soil texture were used as new covariates. As an alternative measure of climate-related change, the community mean value of specific leaf area was used, a functional trait measuring drought tolerance. We investigated whether these revised analyses supported the prediction of lesser sensitivity to climate change in understorey communities on infertile serpentine soils. Overstorey cover, but not macroclimate or soil texture, was a significant covariate of community change over time. It strongly buffered understorey temperatures, was correlated with less change and averaged >50 % lower on serpentine soils, thereby counteracting the lower climate sensitivity of understorey herbs on these soils. Community mean specific leaf area showed the predicted pattern of less change over time in serpentine than non-serpentine communities. Based on the current balance of evidence, plant communities on infertile serpentine soils are less sensitive to changes in the climatic water balance than communities on more fertile soils. However, this advantage may in some cases be lessened by their sparser overstorey cover.

Reakce růstových parametrů papriky na rozdílné úrovně výživy NPK

This work was conducted to study the effect of five NPK fertigation levels on the growth rate of sweet pepper (Capsicum annuum L. cv. Bruyo) grown under the plastic greenhouse using different growth analysis formulas. Leaf area ratio (LAR), specific leaf area (SLA), relative growth rate (RGR) and net assimilation rate (NAR) was evaluated in two periods (60–90 and 90–120 days after transplanting). The mean values of LAR, SLA, RGR and NAR tended to decrease significantly with advancing plant age in both seasons. In general, at the moderate level (34N-42P-29K / plastic house 540 m2) was found the highest significant values of LAR and SLA in the two growth periods. On the other hand, the highest values of NAR were recorded at the plants treated with the lowest NPK fertigation level (17N-21P-15K / plastic house 540 m2). However, increase of NPK fertigation doses to the moderate levels had favorable effects on LAR and SLA of sweet pepper plants.