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Lose well
\"A laugh-out-loud, kick-in-the-pants self-help narrative for anyone who ever felt like they didn't fit in or couldn't catch a break--comedian and cult hero Chris Gethard shows us how to get over our fear of failure and start living life on our own terms\"-- Provided by publisher.
Book
Climate, soil and plant functional types as drivers of global fine-root trait variation
1.Ecosystem functioning relies heavily on belowground processes, which are largely regulated by plant fine-roots and their functional traits. However, our knowledge of fine-root trait distribution relies to date on local- and regional-scale studies with limited numbers of species, growth forms and environmental variation. 2.We compiled a worldwide fine-root trait dataset, featuring 1115 species from contrasting climatic areas, phylogeny and growth forms to test a series of hypotheses pertaining to the influence of plant functional types, soil and climate variables, and the degree of manipulation of plant growing conditions on species fine-root trait variation. Most particularly, we tested the competing hypotheses that fine-root traits typical of faster return on investment would be most strongly associated with conditions of limiting versus favourable soil resource availability. We accounted for both data source and species phylogenetic relatedness. 3.We demonstrate that (1) Climate conditions promoting soil fertility relate negatively to fine-root traits favouring fast soil resource acquisition, with a particularly strong positive effect of temperature on fine-root diameter and negative effect on specific root length (SRL), and a negative effect of rainfall on root nitrogen concentration; (2) Soil bulk density strongly influences species fine-root morphology, by favouring thicker, denser fine-roots; (3) Fine-roots from herbaceous species are on average finer and have higher SRL than those of woody species, and N2-fixing capacity positively relates to root nitrogen; (4) Plants growing in pots have higher SRL than those grown in the field. 4.Synthesis. This study reveals both the large variation in fine-root traits encountered globally and the relevance of several key plant functional types and soil and climate variables for explaining a substantial part of this variation. Climate, particularly temperature, and plant functional types were the two strongest predictors of fine-root trait variation. High trait variation occurred at local scales, suggesting that wide-ranging belowground resource economics strategies are viable within most climatic areas and soil conditions.
Journal Article
Phenological response of tundra plants to background climate variation tested using the International Tundra Experiment
The rapidly warming temperatures in high-latitude and alpine regions have the potential to alter the phenology of Arctic and alpine plants, affecting processes ranging from food webs to ecosystem trace gas fluxes. The International Tundra Experiment (ITEX) was initiated in 1990 to evaluate the effects of expected rapid changes in temperature on tundra plant phenology, growth and community changes using experimental warming. Here, we used the ITEX control data to test the phenological responses to background temperature variation across sites spanning latitudinal and moisture gradients. The dataset overall did not show an advance in phenology; instead, temperature variability during the years sampled and an absence of warming at some sites resulted in mixed responses. Phenological transitions of high Arctic plants clearly occurred at lower heat sum thresholds than those of low Arctic and alpine plants. However, sensitivity to temperature change was similar among plants from the different climate zones. Plants of different communities and growth forms differed for some phenological responses. Heat sums associated with flowering and greening appear to have increased over time. These results point to a complex suite of changes in plant communities and ecosystem function in high latitudes and elevations as the climate warms.
Journal Article
Effects of a spatially heterogeneous nutrient distribution on the growth of clonal wetland plants
Background Clonal plants are important in maintaining wetland ecosystems. The main growth types of clonal plants are the guerrilla and phalanx types. However, little is known about the effects of these different clonal growth types on plant plasticity in response to heterogeneous resource distribution. We compared the growth performance of clonal wetland plants exhibiting the two growth forms (guerrilla growth form: Scirpus yagara, Typha orientalis, Phragmites australis and Sparganium stoloniferum; phalanx growth form: Acorus calamus, Schoenoplectus tabernaemontani and Butomus umbellatus) grown in soil substrates that were either homogeneous or heterogeneous but had the same total amount of nutrients. Results We found that the morphological traits (plant height, ramet number, spacer diameter and length) and biomass accumulation of the guerrilla clonal plants (T. orientalis) were significantly enhanced by heterogeneity, but those of the phalanx clonal plants (A. calamus, S. tabernaemontani and B. umbellatus) were not. The results showed that the benefits of environmental heterogeneity to clonal plants may be correlated with the type of clonal structure. Conclusions Guerrilla clonal plants, which have a dispersed, flexible linear structure, are better suited to habitats with heterogeneous resources. Phalanx clonal plants, which form compact structures, are better suited to habitats with homogeneous resources. Thus, wetland clonal species with the guerrilla clonal structure benefit more from soil nutrient heterogeneity.
Journal Article
global analysis of parenchyma tissue fractions in secondary xylem of seed plants
Parenchyma is an important tissue in secondary xylem of seed plants, with functions ranging from storage to defence and with effects on the physical and mechanical properties of wood. Currently, we lack a large‐scale quantitative analysis of ray parenchyma (RP) and axial parenchyma (AP) tissue fractions. Here, we use data from the literature on AP and RP fractions to investigate the potential relationships of climate and growth form with total ray and axial parenchyma fractions (RAP). We found a 29‐fold variation in RAP fraction, which was more strongly related to temperature than with precipitation. Stem succulents had the highest RAP values (mean ± SD: 70.2 ± 22.0%), followed by lianas (50.1 ± 16.3%), angiosperm trees and shrubs (26.3 ± 12.4%), and conifers (7.6 ± 2.6%). Differences in RAP fraction between temperate and tropical angiosperm trees (21.1 ± 7.9% vs 36.2 ± 13.4%, respectively) are due to differences in the AP fraction, which is typically three times higher in tropical than in temperate trees, but not in RP fraction. Our results illustrate that both temperature and growth form are important drivers of RAP fractions. These findings should help pave the way to better understand the various functions of RAP in plants.
Journal Article
Plant functional groups associate with distinct arbuscular mycorrhizal fungal communities
• The benefits of the arbuscular mycorrhizal (AM) symbiosis between plants and fungi are modulated by the functional characteristics of both partners. However, it is unknown to what extent functionally distinct groups of plants naturally associate with different AM fungi.
• We reanalysed 14 high-throughput sequencing data sets describing AM fungal communities associating with plant individuals (2427) belonging to 297 species. We examined how root-associating AM fungal communities varied between plants with different growth forms, photosynthetic pathways, CSR (competitor, stress-tolerator, ruderal) strategies, mycorrhizal statuses and N-fixing statuses.
• AM fungal community composition differed in relation to all studied plant functional groups. Grasses, C₄ and nonruderal plants were characterised by high AM fungal alpha diversity, while C₄, ruderal and obligately mycorrhizal plants were characterised by high beta diversity. The phylogenetic diversity of AM fungi, a potential surrogate for functional diversity, was higher among forbs than other plant growth forms. Putatively ruderal (previously cultured) AM fungi were disproportionately associated with forbs and ruderal plants. There was phylogenetic correlation among AM fungi in the degree of association with different plant growth forms and photosynthetic pathways.
• Associated AM fungal communities constitute an important component of plant ecological strategies. Functionally different plants associate with distinct AM fungal communities, linking mycorrhizal associations with functional diversity in ecosystems.
Journal Article
Seeing beyond the trees
Forests are the most diverse and productive terrestrial ecosystems on Earth, so sustainably managing them for the future is a major global challenge. Yet, our understanding of forest diversity relies almost exclusively on the study of trees. Here, we demonstrate unequivocally that other growth forms (shrubs, lianas, herbs, epiphytes) make up the majority of vascular plant species in both tropical and temperate forests. By comparing the relative distribution of species richness among plant growth forms for over 3,400 species in 18 forests in the Americas, we construct the first high-resolution quantification of plant growth form diversity across two ecologically important regions at a near-continental scale. We also quantify the physical distribution of plant species among forest layers, that is, where among the vertical strata plants ultimately live their adult lives, and show that plants are strongly downshifted in temperate forests vs. tropical forests. Our data illustrate a previously unquantified fundamental difference between tropical and temperate forests: what plant growth forms are most speciose, and where they ultimately live in the forest. Recognizing these differences requires that we re-focus ecological research and forest management plans to encompass a broader suite of plant growth forms. This more holistic perspective is essential to conserve global biodiversity.
Journal Article
Evolution of shrub-like growth forms in the lianoid subfamily Secamonoideae (Apocynaceae s.l.) of Madagascar: phylogeny, biomechanics, and development
Lianas are common in the Apocynaceae s.l. and are predominant in the subfamily Secamonoideae. Shrub-like taxa are rare within this subfamily but occur in Malagasy genera such as Secamone, Secamonopsis, and PERVILLAEA: We explored the evolutionary appearance of shrub-like growth forms in Malagasy Secamonoideae through a molecular phylogeny using chloroplastic sequences. The phylogeny revealed several independent appearances of shrub-like growth forms within the Secamonoideae. Biomechanics and development of the shrub-like growth form were detailed in one species, Secamone sparsiflora, which has upright and self-supporting young stems that become procumbent in older stages of development. Biomechanical investigations revealed characteristics atypical of both lianas and self-supporting shrubs. Anatomical development in S. sparsiflora is initially similar to lianas in the same clade but shows potentially neotenic retention of juvenile wood development for most of the growth trajectory. The results suggest that evolution of lianescence can carry a high degree of specialization and developmental burden that might limit evolution back to self-supporting growth forms. Under certain geographic and ecological conditions, such as geographic isolation, xeric conditions and/or reduced biotic competition, escapes from lianescence to other growth forms can occur in some angiosperm groups via relatively simple heterochronic shifts of mechanically significant growth processes.
Journal Article
Light and growth form interact to shape stomatal ratio among British angiosperms
In most plants, stomata are located only on the abaxial leaf surface (hypostomy), but many plants have stomata on both surfaces (amphistomy). High light and herbaceous growth form have been hypothesized to favor amphistomy, but these hypotheses have not been rigorously tested together using phylogenetic comparative methods.
I leveraged a large dataset including stomatal ratio, Ellenberg light indicator value, growth form and phylogenetic relationships for 372 species of British angiosperms. I used phylogenetic comparative methods to test how light and/or growth form influence stomatal ratio and density.
High light and herbaceous growth form are correlated with amphistomy, as predicted, but they also interact; the effect of light is pronounced in therophytes (annuals) and perennial herbs, but muted in phanerophytes (shrubs and trees). Furthermore, amphistomy and stomatal density evolve together in response to light.
Comparative analyses of British angiosperms reveal two major insights. First, light and growth form interact to shape stomatal ratio; amphistomy is common under high light, but mostly for herbs. Second, coordinated evolution of adaxial stomatal density and light tolerance indicates that amphistomy helps to optimally balance light acquisition with gas exchange. Stomatal ratio may have potential as a functional trait for paleoecology and crop improvement.
Journal Article
Predicting species' maximum dispersal distances from simple plant traits
Many studies have shown plant species' dispersal distances to be strongly related to life-history traits, but how well different traits can predict dispersal distances is not yet known. We used cross-validation techniques and a global data set (576 plant species) to measure the predictive power of simple plant traits to estimate species' maximum dispersal distances. Including dispersal syndrome (wind, animal, ant, ballistic, and no special syndrome), growth form (tree, shrub, herb), seed mass, seed release height, and terminal velocity in different combinations as explanatory variables we constructed models to explain variation in measured maximum dispersal distances and evaluated their power to predict maximum dispersal distances. Predictions are more accurate, but also limited to a particular set of species, if data on more specific traits, such as terminal velocity, are available. The best model (
R
2
= 0.60) included dispersal syndrome, growth form, and terminal velocity as fixed effects. Reasonable predictions of maximum dispersal distance (
R
2
= 0.53) are also possible when using only the simplest and most commonly measured traits; dispersal syndrome and growth form together with species taxonomy data. We provide a function (dispeRsal) to be run in the software package R. This enables researchers to estimate maximum dispersal distances with confidence intervals for plant species using measured traits as predictors. Easily obtainable trait data, such as dispersal syndrome (inferred from seed morphology) and growth form, enable predictions to be made for a large number of species.
Journal Article