Steven Jansen results 33
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Hydraulic variability of tropical forests is largely independent of water availabilityNARA Subscribed
Tropical rainforest woody plants have been thought to have uniformly low resistance to hydraulic failure and to function near the edge of their hydraulic safety margin (HSM), making these ecosystems vulnerable to drought; however, this may not be the case. Using data collected at 30 tropical forest sites for three key traits associated with drought tolerance, we show that site‐level hydraulic diversity of leaf turgor loss poin...
Optimal balancing of xylem efficiency and safety explains plant vulnerability to droughtNARA Subscribed
In vast areas of the world, forests and vegetation are water limited and plant survival depends on the ability to avoid catastrophic hydraulic failure. Therefore, it is remarkable that plants take hydraulic risks by operating at water potentials ( ψ ) that induce partial failure of the water conduits (xylem). Here we present an eco‐evolutionary optimality principle for xylem conduit design that explains this phenomenon based o...
Biological invasions in remote areas that experience low human activity provide unique opportunities to elucidate processes responsible for invasion success. Here we study the most widespread invasive plant species across the isolated islands of the Southern Ocean, the annual bluegrass, Poa annua . To analyse geographical variation in genome size, genetic diversity and reproductive strategies, we sampled all major sub‐Antarcti...
Human activity strongly influences genetic dynamics of the most widespread invasive plant in the sub‐AntarcticNARA Subscribed
The link between the successful establishment of alien species and propagule pressure is well‐documented. Less known is how humans influence the post‐introduction dynamics of invasive alien populations. The latter requires studying parallel invasions by the same species in habitats that are differently impacted by humans. We analysed microsatellite and genome size variation, and then compared the genetic diversity and structur...
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Hydraulic prediction of drought‐induced plant dieback and top‐kill depends on leaf habit and growth formNARA Subscribed
Hydraulic failure caused by severe drought contributes to aboveground dieback and whole‐plant death. The extent to which dieback or whole‐plant death can be predicted by plant hydraulic traits has rarely been tested among species with different leaf habits and/or growth forms. We investigated 19 hydraulic traits in 40 woody species in a tropical savanna and their potential correlations with drought response during an extreme d...
Functional biogeography of Neotropical moist forests: Trait–climate relationships and assembly patterns of tree communitiesNARA Subscribed
Aim Here we examine the functional profile of regional tree species pools across the latitudinal distribution of Neotropical moist forests, and test trait–climate relationships among local communities. We expected opportunistic strategies (acquisitive traits, small seeds) to be overrepresented in species pools further from the equator, but also in terms of abundance in local communities in currently wetter, warmer and more sea...
Root xylem in three woody angiosperm species is not more vulnerable to embolism than stem xylemNARA Subscribed
Aims Since plants are compartmentalised organisms, failure of their hydraulic transport system could differ between organs. We test here whether xylem tissue of stems and roots differ in their drought-induced embolism resistance, and whether intact roots are equally resistant to embolism than root segments. Methods Embolism resistance of stem and root xylem was measured based on the pneumatic technique for Acer campestre , A....
TRY plant trait database – enhanced coverage and open accessNARA Subscribed
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 biodivers...
Aim Plant trait databases often contain traits that are correlated, but for whom direct (undirected statistical dependency) and indirect (mediated by other traits) connections may be confounded. The confounding of correlation and connection hinders our understanding of plant strategies, and how these vary among growth forms and climate zones. We identified the direct and indirect connections across plant traits relevant to com...
Stomatal response to environmental conditions forms the backbone of all ecosystem and carbon cycle models, but is largely based on empirical relationships. Evolutionary theories of stomatal behaviour are critical for guarding against prediction errors of empirical models under future climates. Longstanding theory holds that stomata maximise fitness by acting to maintain constant marginal water use efficiency over a given time...
Tree mortality is a key factor influencing forest functions and dynamics, but our understanding of the mechanisms leading to mortality and the associated changes in tree growth rates are still limited. We compiled a new pan‐continental tree‐ring width database from sites where both dead and living trees were sampled (2970 dead and 4224 living trees from 190 sites, including 36 species), and compared early and recent growth rat...
Towards a worldwide wood economics spectrumNARA Subscribed
Wood performs several essential functions in plants, including mechanically supporting aboveground tissue, storing water and other resources, and transporting sap. Woody tissues are likely to face physiological, structural and defensive trade‐offs. How a plant optimizes among these competing functions can have major ecological implications, which have been under‐appreciated by ecologists compared to the focus they have given t...