TRY plant trait database – enhanced coverage and open access

Plant traits - the morphological, anatomical, physiological, biochemical and phenological characteristics of plants - determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait‐based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits - almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives

Termite sensitivity to temperature affects global wood decay rates.

Deadwood is a large global carbon store with its store size partially determined by biotic decay. Microbial wood decay rates are known to respond to changing temperature and precipitation. Termites are also important decomposers in the tropics but are less well studied. An understanding of their climate sensitivities is needed to estimate climate change effects on wood carbon pools. Using data from 133 sites spanning six continents, we found that termite wood discovery and consumption were highly sensitive to temperature (with decay increasing >6.8 times per 10°C increase in temperature)-even more so than microbes. Termite decay effects were greatest in tropical seasonal forests, tropical savannas, and subtropical deserts. With tropicalization (i.e., warming shifts to tropical climates), termite wood decay will likely increase as termites access more of Earth's surface

Plant traits demonstrate that temperate and tropical giant eucalypt forests are ecologically convergent with rainforest not savanna.

Ecological theory differentiates rainforest and open vegetation in many regions as functionally divergent alternative stable states with transitional (ecotonal) vegetation between the two forming transient unstable states. This transitional vegetation is of considerable significance, not only as a test case for theories of vegetation dynamics, but also because this type of vegetation is of major economic importance, and is home to a suite of species of conservation significance, including the world's tallest flowering plants. We therefore created predictions of patterns in plant functional traits that would test the alternative stable states model of these systems. We measured functional traits of 128 trees and shrubs across tropical and temperate rainforest - open vegetation transitions in Australia, with giant eucalypt forests situated between these vegetation types. We analysed a set of functional traits: leaf carbon isotopes, leaf area, leaf mass per area, leaf slenderness, wood density, maximum height and bark thickness, using univariate and multivariate methods. For most traits, giant eucalypt forest was similar to rainforest, while rainforest, particularly tropical rainforest, was significantly different from the open vegetation. In multivariate analyses, tropical and temperate rainforest diverged functionally, and both segregated from open vegetation. Furthermore, the giant eucalypt forests overlapped in function with their respective rainforests. The two types of giant eucalypt forests also exhibited greater overall functional similarity to each other than to any of the open vegetation types. We conclude that tropical and temperate giant eucalypt forests are ecologically and functionally convergent. The lack of clear functional differentiation from rainforest suggests that giant eucalypt forests are unstable states within the basin of attraction of rainforest. Our results have important implications for giant eucalypt forest management

Seasonal pollen distribution in the atmosphere of Hobart, Tasmania: preliminary observations and congruence with flowering phenology

The atmospheric pollen loads of Hobart, Tasmania, Australia, were monitored between September 2007 and July 2009. To examine the match of the airborne pollen composition with the flowering duration of their contributing plants, the phenology of native and non-native plants in various habitats near the pollen-trapping site was undertaken between August 2008 and July 2009. The pollen load was found to have a strong seasonal component associated with the start of spring in September. This is incongruent with the peak flowering season of the total taxa in October. In most taxa, atmospheric pollen signatures appeared before flowering was observed in the field. The presence of most pollen types in the atmosphere also exceeded the observed flowering duration of potential pollen-source taxa. Reasons for this may be related to the sampling effort of phenological monitoring, pollen blown in from earlier flowering populations outside of the sampling area, the ability of pollen to be reworked, and the large pollen production of some wind-pollinated taxa. In 20072008, 15 pollen types dominated the atmosphere, accounting for 90% of the airborne pollen load. The top six pollen types belonged to Betula, Cupressaceae, Myrtaceae, Salix, Poaceae and Ulmus. Comparatively, the annual pollen load of Hobart is lower than in most other Australian cities; however, the pollen signal of Betula is inordinately high. Native plants play a minor role as pollen contributors, despite the proximity of native habitats to the pollen-sampling location. The implications of the aerobiological observations are discussed in relation to public health

Canonical variate analyses of functional trait means of 128 species from tropical and (closed circles) temperate (open circles) rainforest (black), giant eucalypt forest (blue) and savanna (orange).

<p>Six functional traits were used: carbon isotopes (δ13C); leaf area; leaf mass per area (LMA); leaf slenderness (LS); wood density, and; maximum height plotted into multivariate space. Each dot represents a species. On the bottom right the trait weightings (transformed where required) are plotted onto the graphs as vectors whose length and direction represent the contribution of the variable in explaining the clustering pattern. For each vegetation group, each multivariate mean is visualized as large grey circles encircling a black cross, the size of which corresponds to the 95% confidence limit for the mean. Groups that are significantly different tend to have non-intersecting circles. The proximities and overlaps of these circles are used to corroborate trait behavior with Alternative Stable States model scenarios (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084378#pone-0084378-g001" target="_blank">Figure 1</a>). The bottom left inset is the results of pairwise <i>post-hoc</i> tests of a one-way MANOVA where unbroken lines represent significant differences between vegetation types, and dashed lines represent non-significance. </p

Boxplots showing the bole trait behavior of rainforest (grey), giant eucalypt forest (blue) and savanna (orange) species from the tropical north Queensland (left block) and the cool temperate Tasmania (right block).

<p>Shown are wood density (WD), maximum height (Ht_max), and bark thickness index (BT_index). Each box encompasses the 25th to 75th percentiles; the median is indicated by the boldest vertical line and the other vertical lines outside the box indicate the 10th and 90th percentiles. Dots indicate outliers. One-way ANOVAs were performed on the log-transformed data (except WD) and significant differences between vegetation types are indicated by different letters based on Tukey HSD tests at a 0.05 confidence level (see Methods; <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0084378#pone-0084378-t002" target="_blank">Table 2</a>).</p

The distribution of rainforest (black) and giant eucalypt forest (blue) along the east coast of the Australian continent.

<p>The orange-coloured regions are open vegetation (including savanna and open eucalypt woodland). The ecotonal nature of giant eucalypt forest is most pronounced in tropical north Queensland, where giant eucalypt forests form narrow bands between rainforest and savanna (spatial extent exaggerated for clarity), and in cool temperate Tasmania, where giant eucalypt forests form a broad transition between the west and the eastern parts of the island. The inset images feature representative rainforests, giant eucalypt forests and open vegetation of the tropical and temperate zones. Note the taller stature and open canopy of giant eucalypts relative to rainforest in the understoreys.</p

Idealised Alternative Stable States ‘ball and cup’ scenarios for rainforest (dark grey), giant eucalypt forest (blue) and open vegetation (orange) and their corresponding hypothesized trait behavior in univariate and multivariate analysis outputs.

<p>In each case, the overlap between to the confidence limits of each functional profile will denote the functional affinities between habitats.</p

Numerical simulation of mechanical vibration induced membrane surface shear stress in a pilot-scale vibration MBR

Numerical simulation of mechanical vibration induced membrane surface shear stress in a pilot-scale vibration MBRXuefei Liu*, Keng Han Tng*, Wenbo Fan**, Pan Dai**, Jing Guan**, Yuan Wang*, Greg Leslie** UNESCO Centre for Membrane Science & Technology, University of New South Wales, Sydney 2052, Australia** Beijing Origin Water, Huairou, Beijing, 101400, P.R. ChinaKeywords: Vibration; MBR; CFD; strain gauge; FSIIntroduction Experimental trials at laboratory and pilot scale have been conducted using oscillatory vibration to replace aeration in Membrane Bioreactor (MBR) processes to prevent solid accumulation on membrane surface by generating high shear stress in recent years. The use of such vibration systems has been reported to be more energy efficient, with up to a 75% reduction in energy consumption when compared to conventional coarse bubble aeration systems (Ho et al., 2014). Vibration of membrane modules with higher frequency and larger amplitude has been proposed to significantly increase critical flux (Genkin et al., 2006), however this method requires higher vibrational energy input. Contrastingly, low-frequency vibration could decrease total energy demand for vibrational systems. However, low-frequency systems require enhanced mixing, such as low-intensity fine bubble aeration, which prevents hydraulic dead-zones and provides dissolved oxygen in aerobic MBRs. This study investigated the distribution of shear stress in flat sheet membrane modules induced by low-frequency membrane vibration coupled with low-intensity aeration using Fluid Structure Interaction (FSI) simulation. MethodsA two-way Fluid Structure Interaction (FSI) simulation was performed on a pilot-scale vibration membrane tank (4300 L) operated in Yanxi Wastewater Treatment Plant (Beijing, China). The hydraulic performance of the membrane tank induced by mechanical vibration (0.625 Hz frequency and 107.5 mm amplitude) of flat sheet membrane module (19.2 m2) in the presence of 20 Nm3/hr fine bubble aeration was simulated using a two-phase CFD model (ANSYS FLUENT v17.2). The rheological property of mixed liquor was simulated by incorporating an experimentally calibrated rheological model (Liu et al., 2014). The membrane deformation and membrane surface strain were simulated using a transient structural model (ANSYS Transient Structural module). The two-way system coupling was implemented to simulate the interaction between membrane module and the two-phase fluid flow. The model was validated by a novel mechanical characterisation method using water proof strain gauges to measure the localized strain on the membrane surface. Results and Discussion The simulation results demonstrated that the shear stress on the flat sheet membrane surface as induced by membrane vibration (0.625 s frequency,107.5 mm amplitude) in the presence of low-intensity aeration (20 Nm3/hr) was homogeneously distributed throughout the whole membrane module, except small regions (< 5% of the effective membrane area) near the four edges of the membrane sheet (Figure 1a). Higher membrane surface shear was obtained at the upper and lower edges where flow enters and exits the membrane module, while lower shear stress was observed near permeate collectors. The area-averaged shear stress exhibited a periodic variation with an average period of 0.8 s, half of the period of membrane movement and a resulting time-averaged shear stress of 2.86 Pa (Figure 1b). A peak area-averaged shear of 4.21 Pa was obtained at the largest relative motion between the mid-point flow (flow velocity at the mid-point of flow channel) and membrane. In contrast, the trough of the area-averaged shear stress was obtained when mid-point flow velocity was the same as the membrane velocity (Figure 1b). Figure 1. a) Simulated shear stress distribution in membrane module and b) Simulated comparison of mid-point flow velocity, membrane velocity and average membrane surface shear stress as a function of time.ConclusionsThe novel FSI model developed in this study were used to understand the impact of vibrating frequency and intensity on membrane surface shear and fouling control, which can be used to provide guidance and optimise MBR membrane module design with low-frequency vibration systems to improve fouling control. ReferencesGenkin, G., Waite, T. D., Fane, A. G., & Chang, S. (2006). The effect of vibration and coagulant addition on the filtration performance of submerged hollow fibre membranes. Journal of membrane science, 281(1), 726-734.Ho, J., Smith, S., & Roh, H. K. (2014). Alternative energy efficient membrane bioreactor using reciprocating submerged membrane. Water Science and Technology, 70(12), 1998-2003.Liu, X., Wang, Y., Waite, T. D., & Leslie, G. (2015). Numerical simulation of bubble induced shear in membrane bioreactors: effects of mixed liquor rheology and membrane configuration. Water research, 75, 131-145

Comparative Chloroplast Genomics of Litsea Lam. (Lauraceae) and Its Phylogenetic Implications

Litsea Lam. is an ecological and economic important genus of the “core Lauraceae” group in the Lauraceae. The few studies to date on the comparative chloroplast genomics and phylogenomics of Litsea have been conducted as part of other studies on the Lauraceae. Here, we sequenced the whole chloroplast genome sequence of Litsea auriculata, an endangered tree endemic to eastern China, and compared this with previously published chloroplast genome sequences of 11 other Litsea species. The chloroplast genomes of the 12 Litsea species ranged from 152,132 (L. szemaois) to 154,011 bp (L. garrettii) and exhibited a typical quadripartite structure with conserved genome arrangement and content, with length variations in the inverted repeat regions (IRs). No codon usage preferences were detected within the 30 codons used in the chloroplast genomes, indicating a conserved evolution model for the genus. Ten intergenic spacers (psbE–petL, trnH–psbA, petA–psbJ, ndhF–rpl32, ycf4–cemA, rpl32–trnL, ndhG–ndhI, psbC–trnS, trnE–trnT, and psbM–trnD) and five protein coding genes (ndhD, matK, ccsA, ycf1, and ndhF) were identified as divergence hotspot regions and DNA barcodes of Litsea species. In total, 876 chloroplast microsatellites were located within the 12 chloroplast genomes. Phylogenetic analyses conducted using the 51 additional complete chloroplast genomes of “core Lauraceae” species demonstrated that the 12 Litsea species grouped into four sub-clades within the Laurus-Neolitsea clade, and that Litsea is polyphyletic and closely related to the genera Lindera and Laurus. Our phylogeny strongly supported the monophyly of the following three clades (Laurus–Neolitsea, Cinnamomum–Ocotea, and Machilus–Persea) among the above investigated “core Lauraceae” species. Overall, our study highlighted the taxonomic utility of chloroplast genomes in Litsea, and the genetic markers identified here will facilitate future studies on the evolution, conservation, population genetics, and phylogeography of L. auriculata and other Litsea species