Primary succession and plant functional traits on an oceanic island

Previous studies have shown variable relationships between dispersal rate and ecosystem functioning, but the reasons for and mechanisms behind variable dispersal rate – functioning patterns are currently unknown. In this study we used six bacterial lake water communities in a laboratory experiment in order to investigate how dispersal among communities influences community productivity by evaluating three different mechanisms: 1) changes in taxonomic diversity, 2) changes in phylogenetic diversity or 3) changes in the composition of functional traits. The experiment was conducted in two phases; (A) a dialysis bag experiment where the dispersal rate among six communities was manipulated and the subsequent change in bacterial diversity and growth rate was recorded, and (B) a regrowth experiment where we manipulated available resources to study how well a taxon grows on certain organic carbon resources, i.e. their functional traits. From experiment (B) we could thus estimate changes in functional traits in communities in experiment (A). Bacterial production was affected by dispersal, but not consistently among lakes. Neither change in taxonomic or phylogenetic diversity with dispersal could explain the observed dispersal – productivity relationships. Instead, changes in trait composition with dispersal, especially the communities’ ability to use p-coumaric acid, an aromatic compound, could explain the observed dispersal – productivity relationships. Changes in this trait caused by dispersal seemed especially important for bacterial productivity in waters with a high aromaticity of the organic matter pool. We conclude that the effect of dispersal on bacterial communities can affect ecosystem functioning in different ways, through changes in functional key-traits which are important for the local environment.

Environmental factors drive changes in plant functional traits, which in turn promote community recovery. The environmental conditions of the community are different at different recovery stages. Changing environmental factors may drive the changes in plant functional traits at the community level and affect species adaptation. We studied plant communities in five different recovery stages (herb, grass and shrub, shrub, tree and shrub, and tree) in the karst plateau of Zhenning, Guizhou (The vegetation in the study area has undergone a gradual natural recovery process after the forests were deforested in 1958–1960). We studied functional traits and their links to environmental factors. The main results include the following. (1) Over time, plant height, leaf dry matter content, leaf nitrogen content and leaf phosphorus content increased significantly in the tree stage, while leaf thickness and specific leaf area decreased significantly in the tree stage. (2) Soil organic carbon, soil N content, soil P content, soil C:P and soil C:K showed an increasing trend, and were significantly higher in tree stage than in other stages. Soil potassium content fluctuated and soil bulk density decreased gradually, reaching the lowest value in the tree stage, but the difference was not significant. (3) During the restoration process, the functional characteristics changed from a combination of plant communities with high specific leaf area and low dry matter content with a short plant height to plant communities with low specific leaf area and high dry matter content with a tall plant height. (4) As recovery proceeded, the study area gradually changed from a soil nutrient‐poor environment to a nutrient‐rich environment. Overall, the environmental factors vary greatly during the recovery of plant communities in karst areas. The plant community shifts from an aggressive (resource acquisition) to a conservative (environmental barrenness resistance) ecological strategy. The soil phosphorus content and soil C:K are the main environmental factors affecting the changes in functional traits during the restoration of karst plant communities in Zhenning.

The mechanisms driving changes in dominant plant species are the key for understanding how grassland ecosystems respond to climate change. In this study, we examined plant functional traits (morphological characteristics: plant height, leaf area, and leaf number; biomasses: aboveground, belowground, and total; and growth indices: root-to-shoot ratio, specific leaf area, and leaf mass ratio) of four zonal Stipa species (S. baicalensis, S. bungeana, S. grandis, and S. breviflora) from Inner Mongolian grassland in response to warming (control, +1.5, +2.0, +4.0, and +6.0?), changing precipitation (-30%, -15%, control, +15%, and +30%), and their combined effects via climate control chambers. The results showed that warming and changing precipitation had significant interactive effects, different from the accumulation of single-factor effects, on functional traits of Stipa species. The correlation and sensitivity of different plant functional traits to temperature and precipitation differed. Among the four species, the accumulation and variability of functional traits had greater partial correlation with precipitation than temperature, except for leaf number, leaf area, and specific leaf area, in S. breviflora, S. bungeana, and S. grandis. For S. baicalensis, the accumulation and variability of plant height, aboveground biomass, and root-to-shoot ratio only had significant partial correlation with precipitation. However, the variability of morphological characteristics, biomasses, and some growth indices, was more sensitive to temperature than precipitation in S. bungeana, S. grandis, and S. breviflora—except for aboveground biomass and plant height. These results reveal that precipitation is the key factor determining the growth and changes in plant functional traits in Stipa species, and that temperature mainly influences the quantitative fluctuations of the changes in functional traits.

Long-term functional structure and functional diversity changes in Scottish grasslands

Increased nutrient inputs can cause shifts in plant community composition and plant functional traits, both of which affect ecosystem function. We studied community‐ and species‐level leaf functional trait changes in a full factorial nitrogen (N), phosphorus (P), and potassium (K) fertilization experiment in a semi‐arid grassland. Nitrogen was the only nutrient addition to significantly affect leaf functional traits, and N addition increased community‐weighted specific leaf area (SLA) by 19%, leaf chlorophyll content by 34%, height by 26%, and leaf dry matter content (LDMC) decreased by 11% while leaf thickness and toughness did not change significantly. At the species level, most species contributed to the community‐weighted trait and increased inSLA, chlorophyll, height, andLDMCwith N addition. These intraspecific changes in functional traits account for 51–71% of the community‐level changes inSLA, chlorophyll, plant height, andLDMC. The remaining change is due to species abundance changes; the two most abundant species (Bouteloua gracilisandCarex filifolia) decreased in abundance with N addition while subdominant species increased in abundance. We also found annual variation inSLA, chlorophyll, plant height, andLDMCto be as important in influencing traits as N addition, likely due to differences in precipitation. Aboveground net primary productivity (ANPP) did not change significantly with N addition. However, N addition caused a 34% increase in leaf area index (LAI) and a 67% increase in canopy chlorophyll density. We demonstrate that nitrogen‐induced changes in both functional traits and species abundances magnifyANPPchanges inLAIand canopy chlorophyll density. Therefore,ANPPunderestimates N addition‐induced ecosystem‐level changes in the canopy vegetation.

Changes in plant cover and functional traits induced by grazing in the arid Patagonian Monte

Climate warming causes upward shifts in plant species distributions, resulting in an influx of species from lower elevations into alpine plant communities. Plant functional trait changes along elevation gradients and over time may reflect these changing conditions. Intraspecific trait variation measured from herbarium records offers a way to observe such changes in trait values over time. We selected four species: Poa alpina and Polygonum viviparum found in alpine grasslands, and Cardamine resedifolia and Ranunculus glacialis found in high‐alpine to subnival scree habitats. We measured several functional traits from (i) herbarium records collected between 1880 and 1950 and from (ii) individuals resampled in 2014 along an elevation gradient covering >1500 m within the same study region in the Swiss Alps. By comparing (i) against (ii) for each species separately, we analysed temporal changes in the distribution of traits along the studied elevation gradient. After a century of climate warming, the change in the relationship linking plant functional traits with elevation was species dependent. Size‐related and reproductive functional trait values for P. viviparum increased over time, increasing at lower, but not higher elevations. Poa alpina's size‐related traits increased consistently with time along the elevation gradient. Most of C. resedifolia's size‐related and flowering traits decreased over time at lower elevations and converged at higher elevations. Finally, R. glacialis traits did not respond to time alone—reproductive traits decreased over time at lower, and increased at higher elevations, reversing their historical trait distributions. The negative trend for vegetative trait values with elevation did not change over time, however. In 2014, at lower elevations, all species mainly occurred on their typical microhabitat types, but occurrence on other microhabitats increased with elevation for all species. Synthesis: Contrasting temporal changes in the distribution of growth and reproductive trait values between alpine grassland and alpine‐subnival scree species, especially at lower elevations, suggest that climate warming effects vary among species. Additionally, species' physiological constraints and availability of suitable microhabitats may further impact species' distribution changes. Further warming may confine the distribution of high‐alpine plant species to even higher elevations, or microclimates currently difficult to colonise by lower‐alpine species.

During succession, plant species composition undergoes changes that may have implications for ecosystem functions. Here we aimed to study changes in plant species diversity, functional diversity and functional traits associated with mire development. We sampled vegetation from 22 mires on the eastern shore of the Gulf of Bothnia (west coast of Finland) that together represent seven different time steps along a mire chronosequence resulting from post-glacial rebound. This chronosequence spans a time period of almost 2500 years. Information about 15 traits of vascular plants and 17 traits of mosses was collected, mainly from two different databases. In addition to species richness and Shannon diversity index, we measured functional diversity and community weighted means of functional traits. We found that plant species diversity increased from the early succession stages towards the fen–bog transition. The latter stage also has the most diverse surface structure, consisting of pools and hummocks. Functional diversity increased linearly with species richness, suggesting a lack of functional redundancy during mire succession. On the other hand, Rao’s quadratic entropy, another index of functional diversity, remained rather constant throughout the succession. The changes in functional traits indicate a trade-off between acquisitive and conservative strategies. The functional redundancy, i.e. the lack of overlap between similarly functioning species, may indicate that the resistance to environmental disturbances such as drainage or climate change does not change during mire succession. However, the trait trade-off towards conservative strategy, together with the developing microtopography of hummocks and hollows with strongly differing vegetation composition, could increase resistance during mire succession.

Topography related habitat associations of tree species traits, composition and diversity in a Chinese tropical forest

The Evolution of Functional Traits in Plants: Is the Giant Still Sleeping?

Excessive grazing causes a decrease in plant diversity of grassland and also leads to changes in the functional traits of grassland plants. Based on the relationship between plant diversity and the functional traits of constructive species, the patterns of change in plant diversity can be predicted based on change in plant functional traits under different stocking rates. For the present study, Stipa breviflora desert steppe in Inner Mongolia was studied to characterize the plant community and population characteristics and plant functional traits of S. breviflora in grazing areas with different stocking rates [without grazing, light grazing (LG, 0.93 sheep unit hm–2half yr–1), moderate grazing (MG, 1.82 sheep unit hm–2half yr–1), heavy grazing (HG, 2.71 sheep unit hm–2 half yr–1)]. The results showed that: (1) LG significantly weakened the competitive advantage of the constructive species (S. breviflora) (P < 0.05), while HG significantly strengthened its competitive advantage in the community (P < 0.05); (2) Changes in plant diversity were generally significantly related to changes in S. breviflora root traits. The competitive advantage of S. breviflora in the community and the change in root traits could be used to predict the change in plant diversity in the desert steppe under different stocking rates. This research can provide a theoretical basis for maintaining plant diversity and sustainability in the desert steppe.

Methods of reconstructing changes in plant traits over long time scales are needed to understand the impact of changing environmental conditions on ecosystem processes and services. Although Holocene pollen have been extensively used to provide records of vegetation history, few studies have adopted a functional trait approach that is pertinent to changes in ecosystem processes. Here, for woody and herbaceous fen peatland communities, we use modern pollen and vegetation data combined with pollen records from Holocene deposits to reconstruct vegetation functional dynamics. The six traits chosen (measures of leaf area-to-mass ratio and leaf nutrient content) are known to modulate species’ fitness and to vary with changes in ecosystem processes. We fitted linear mixed effects models between community weighted mean (CWM) trait values of the modern pollen and vegetation to determine whether traits assigned to pollen types could be used to reconstruct traits found in the vegetation from pollen assemblages. We used relative pollen productivity (RPP) correction factors in an attempt to improve this relationship. For traits showing the best fit between modern pollen and vegetation, we applied the model to dated Holocene pollen sequences from Fenland and Romney Marsh in eastern and southern England and reconstructed temporal changes in trait composition. RPP adjustment did not improve the linear relationship between modern pollen and vegetation. Leaf nutrient traits (leaf C and N) were generally more predictable from pollen data than mass-area traits. We show that inferences about biomass accumulation and decomposition rates can be made using Holocene trait reconstructions. While it is possible to reconstruct community-level trends for some leaf traits from pollen assemblages preserved in sedimentary archives in wetlands, we show the importance of testing methods in modern systems first and encourage further development of this approach to address issues concerning the pollen-plant abundance relationship and pollen source area.

El Niño events generate periods of relatively low precipitation, low cloud cover and high temperature over the rainforests of Southeast Asia, but their impact on tree physiology remains poorly understood. Here we use remote sensing and functional trait approaches—commonly used to understand plant acclimation to environmental fluctuations—to evaluate rainforest responses to an El Niño event at a site in northern Borneo. Spaceborne measurements (i.e. normalised difference vegetation index calculated from Moderate Resolution Imaging Spectroradiometer data) show the rainforest canopy greened throughout 2015, coinciding with a strengthening of the El Niño event in Sabah, Malaysia, then lost greenness in early 2016, when the El Niño was at its peak. Leaf chemical and structural traits measured for mature leaves of 65 species (104 branches from 99 tree canopies), during and after this El Niño event revealed that chlorophyll and carotenoid concentrations were 35% higher in mid 2015 than in mid 2016. Foliar concentrations of the nutrients N, P, K and Mg did not vary, suggesting the mineralisation and transportation processes were unaffected by the El Niño event. Leaves contained more phenolics, tannins and cellulose but less Ca and lignin during the El Niño event, with concentration shifts varying strongly among species. These changes in functional traits were also apparent in hyperspectral reflectance data collected using a field spectrometer, particularly in the shortwave infrared region. Leaf-level acclimation and leaf turnover could have driven the trait changes observed. We argue that trees were not water limited in the initial phase of the El Niño event, and responded by flushing new leaves, seen in the canopy greening trend and higher pigment concentrations (associated with young leaves); we argue that high evaporative demand and depleted soil water eventually caused leaves to drop in 2016. However, further studies are needed to confirm these ideas. Time-series of vegetation dynamics obtained from space can only be understood if changes in functional traits, as well as the quantity of leaves in canopies, are monitored on the ground.

Shrimp aquaculture has caused broadscale shifts in mangrove ecosystems worldwide, including changes in habitats and functional traits of mangroves, to the point of widespread destruction in some countries. The propagule is an important stage in mangrove life history, reflecting the resource investment of parents and the ability of offspring to build a population. However, the impacts of shrimp aquaculture effluent on propagule functional traits and stoichiometry are poorly understood. Here, we comparatively investigated the functional traits and stoichiometry of Aegiceras corniculatum propagules in different shrimp aquaculture effluent-affected habitats on the coast of the South China Sea, including a control plot with no effluent discharge, a direct discharge area, and a landfill restoration area. We found that shrimp aquaculture effluent was associated with substantial impacts on the functional traits and stoichiometry of A. corniculatum propagules. In functional traits, both propagule morphology and biomass traits decreased in habitats affected by shrimp aquaculture effluent; in stoichiometry, the discharge of shrimp aquaculture effluent increased N and P contents, and after stopping the discharge, N and P in propagules remained at high concentration; propagule C/N and C/P ratios in all habitats were consistent with those of soils in that both were reduced and exhibited consistent N limits. Our findings highlight the effects of shrimp aquaculture effluent on functional traits and stoichiometric characteristics of A. corniculatum propagules, which may help improve our understanding of the underlying mechanisms of mangrove propagule adaptability. It also provides a scientific basis for assessing its impact on mangrove reproduction potential and population renewal and applies to mangrove management and restoration.

PDF HTML阅读 XML下载 导出引用 引用提醒 海岛植物不同演替阶段植物功能性状与环境因子的变化规律 DOI: 10.5846/stxb201807051468 作者: 作者单位: 福建农林大学,福建农林大学,福建农林大学,云南大学,福建农林大学 作者简介: 通讯作者: 中图分类号: 基金项目: 福建省自然科学基金面上项目（2018J01699）；国家自然科学基金项目（31800401）；福建省教育厅科技项目（JAT170198） Summary of changes in plant functional traits and environmental factors in different successional stages of island plants Author: Affiliation: Fujian Agriculture and Forestry University,Fujian Agriculture and Forestry University,Fujian Agriculture and Forestry University,,Fujian Agriculture and Forestry University Fund Project: 省、部研究计划基金, 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:植物功能性状与环境之间的关系是功能性状研究的重点，环境因子驱使植物功能性状发生变化，进而推动群落发生演替。以平潭岛4个不同演替阶段的森林植被（灌草丛、针叶林、针阔混交林、常绿阔叶林）为研究对象，结合不同群落演替阶段的物种特征和群落结构，分析海岛不同演替阶段茎、叶功能性状的变化规律，以及功能性状与环境因子的关系。结果表明：（1）随着演替的进行，土壤养分和水分逐渐增加，土壤pH逐渐下降。比叶面积（SLA）、叶片氮含量（LNC）、叶片磷含量（LPC）、茎氮含量（SNC）、茎磷含量（SPC）下降后上升，叶厚度（LT）、叶片碳含量（LCC）、茎碳含量（SCC）与之相反，叶干物质含量（LDMC）、茎组织密度（STD）逐渐上升。（2）冗余分析表明，演替早期植物主要分布在土壤pH、容重高的贫瘠环境，拥有较高SLA、SNC、SPC、LPC的性状组合；演替后期植物主要分布在土壤养分和水分高的肥沃环境，拥有较高的STD、LDMC、LCC、LNC的性状组合。其中，土壤有机质和全氮含量是影响海岛植物演替过程中功能性状变化的关键环境因子。研究海岛植物功能性状与环境之间的关系随演替的变化规律，探讨各演替阶段功能性状和环境特征，以及功能性状如何响应环境变化。旨在为今后选择合适的树种进行海岛植被修复和重建提供依据。 Abstract:The relationship between plant functional traits and environment is the focus of functional traits research. Environmental factors drive the changes in plant functional traits, which in turn promote community succession. Based on the forest vegetation of four different succession stages (shrub-grassland, coniferous forest, mixed wood, and broadleaf forest) in Pingtan Island, this study combined the species characteristics and community structure of different community successional stages. We analyzed the changes in stem and leaf functional traits in different succession stages of island plants. Moreover, we explored the relationship between plant functional traits and environmental factors. The results showed the following. (1) With progress in succession, soil nutrient and water content gradually increased and the soil pH gradually decreased. The specific leaf area (SLA), leaf nitrogen content (LNC), leaf phosphorus content (LPC), stem nitrogen content (SNC), and stem phosphorus content (SPC) decreased initially, and then increased, Meanwhile, the leaf thickness (LT), leaf carbon content (LCC), and stem carbon content (SCC) increased initially, and then decreased. The leaf dry matter content (LDMC) and stem tissue density (STD) gradually increased. (2) The redundancy analysis showed that the early succession plants were mainly distributed in barren environments with high soil pH and high bulk density, and they presented higher SLA, SNC, SPC, and LPC. Plants in the late succession stages were mainly distributed in fertile environments with high soil nutrient and water content, and they presented higher STD, LDMC, LCC, and LNC. Therefore, soil organic matter and total nitrogen are the important environmental factors that affect the functional traits of island plants succession. We studied the relationship between plant functional traits and environment along with the changes in succession, understood the functional traits and environmental characteristics of each succession stage, and revealed how plant functional traits adapted to the environmental changes. The study provides the basis for the selection of suitable tree species for island vegetation restoration and reconstruction in the future. 参考文献 相似文献 引证文献