17 research outputs found
Linking leaf economic and hydraulic traits with early-age growth performance and survival of Eucalyptus pauciflora
Selection on plant functional traits may occur through their direct effects on
fitness (or a fitness component), or may be mediated by attributes of plant
performance which have a direct impact on fitness. Understanding this link is
particularly challenging for long-lived organisms, such as forest trees, where
lifetime fitness assessments are rarely achievable, and performance features
and fitness components are usually quantified from early-life history stages.
Accordingly, we studied a cohort of trees from multiple populations of
Eucalyptus pauciflora grown in a common-garden field trial established at
the hot and dry end of the species distribution on the island of Tasmania,
Australia. We related the within-population variation in leaf economic (leaf
thickness, leaf area and leaf density) and hydraulic (stomatal density, stomatal
length and vein density) traits, measured from two-year-old plants, to two-year
growth performance (height and stem diameter) and to a fitness component
(seven-year survival). When performance-trait relationships were modelled for
all traits simultaneously, statistical support for direct effects on growth
performance was only observed for leaf thickness and leaf density.
Performance-based estimators of directional selection indicated that
individuals with reduced leaf thickness and increased leaf density were
favoured. Survival-performance relationships were consistent with size-
dependent mortality, with fitness-based selection gradients estimated for
performance measures providing evidence for directional selection favouring
individuals with faster growth. There was no statistical support for an effect
associated with the fitness-based quadratic selection gradient estimated for
growth performance. Conditional on a performance measure, fitness-based
directional selection gradients estimated for the leaf traits did not provide
statistical support for direct effects of the focal traits on tree survival. This
suggested that, under the environmental conditions of the trial site and time
period covered in the current study, early-stage selection on the studied leaf
traits may be mediated by their effects on growth performance, which in turn has a positive direct influence on later-age survival. We discuss the potential
mechanistic basis of the direct effects of the focal leaf traits on tree growth, and
the relevance of a putative causal pathway of trait effects on fitness through
mediation by growth performance in the studied hot and dry environmentinfo:eu-repo/semantics/publishedVersio
Leaf Economic and Hydraulic Traits Signal Disparate Climate Adaptation Patterns in Two Co-Occurring Woodland Eucalypts
With climate change impacting trees worldwide, enhancing adaptation capacity has become
an important goal of provenance translocation strategies for forestry, ecological renovation, and
biodiversity conservation. Given that not every species can be studied in detail, it is important
to understand the extent to which climate adaptation patterns can be generalised across species,
in terms of the selective agents and traits involved. We here compare patterns of genetic-based
population (co)variation in leaf economic and hydraulic traits, climate–trait associations, and genomic
differentiation of two widespread tree species (Eucalyptus pauciflora and E. ovata). We studied 2-yearold
trees growing in a common-garden trial established with progeny from populations of both
species, pair-sampled from 22 localities across their overlapping native distribution in Tasmania,
Australia. Despite originating from the same climatic gradients, the species differed in their levels of
population variance and trait covariance, patterns of population variation within each species were
uncorrelated, and the species had different climate–trait associations. Further, the pattern of genomic
differentiation among populations was uncorrelated between species, and population differentiation
in leaf traits was mostly uncorrelated with genomic differentiation. We discuss hypotheses to
explain this decoupling of patterns and propose that the choice of seed provenances for climatebased
plantings needs to account for multiple dimensions of climate change unless species-specific
information is availableinfo:eu-repo/semantics/publishedVersio
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
Using multi-platform LiDAR to guide the conservation of the world’s largest temperate woodland
Leaf Economic and Hydraulic Traits Signal Disparate Climate Adaptation Patterns in Two Co-Occurring Woodland Eucalypts
With climate change impacting trees worldwide, enhancing adaptation capacity has become an important goal of provenance translocation strategies for forestry, ecological renovation, and biodiversity conservation. Given that not every species can be studied in detail, it is important to understand the extent to which climate adaptation patterns can be generalised across species, in terms of the selective agents and traits involved. We here compare patterns of genetic-based population (co)variation in leaf economic and hydraulic traits, climate–trait associations, and genomic differentiation of two widespread tree species (Eucalyptus pauciflora and E. ovata). We studied 2-year-old trees growing in a common-garden trial established with progeny from populations of both species, pair-sampled from 22 localities across their overlapping native distribution in Tasmania, Australia. Despite originating from the same climatic gradients, the species differed in their levels of population variance and trait covariance, patterns of population variation within each species were uncorrelated, and the species had different climate–trait associations. Further, the pattern of genomic differentiation among populations was uncorrelated between species, and population differentiation in leaf traits was mostly uncorrelated with genomic differentiation. We discuss hypotheses to explain this decoupling of patterns and propose that the choice of seed provenances for climate-based plantings needs to account for multiple dimensions of climate change unless species-specific information is available
Application and validation of visual fuel hazard assessments in dry Mediterranean-climate woodlands
After the fence: vegetation and topsoil condition in grazed, fenced and benchmark eucalypt woodlands of fragmented agricultural landscapes
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.</p
Additional results from the first dedicated search for neutron–mirror–neutron oscillations
The existence of a mirror world holding a copy of our ordinary particle spectrum could lead to oscillations between the neutron (n) and its mirror partner (n′). Such oscillations could manifest themselves in storage experiments with ultracold neutrons whose storage lifetime would depend on the applied magnetic field. Here, extended details and measurements from the first dedicated experimental search for nn′ oscillations published in [G. Ban, K. Bodek, M. Daum, R. Henneck, S. Heule, M. Kasprzak, N. Khomutov, K. Kirch, S. Kistryn, A. Knecht, P. Knowles, M. Kuźniak, T. Lefort, A. Mtchedlishvili, O. Naviliat-Cuncic, C. Plonka, G. Quéméner, M. Rebetez, D. Rebreyend, S. Roccia, G. Rogel, M. Tur, A. Weis, J. Zejma, G. Zsigmond, Direct experimental limit on neutron mirror–neutron oscillations, Phys. Rev. Lett. 99 (2007) 161603] will be presented, focussing on a possible dependence of the UCN counts on the magnetic field and its direction. However, at present no significant change in the averaged UCN counts with respect to the applied magnetic field has been found
Extreme drought impacts have been underestimated in grasslands and shrublands globally.
Climate change is increasing the frequency and severity of short-term (~1 y) drought events-the most common duration of drought-globally. Yet the impact of this intensification of drought on ecosystem functioning remains poorly resolved. This is due in part to the widely disparate approaches ecologists have employed to study drought, variation in the severity and duration of drought studied, and differences among ecosystems in vegetation, edaphic and climatic attributes that can mediate drought impacts. To overcome these problems and better identify the factors that modulate drought responses, we used a coordinated distributed experiment to quantify the impact of short-term drought on grassland and shrubland ecosystems. With a standardized approach, we imposed ~a single year of drought at 100 sites on six continents. Here we show that loss of a foundational ecosystem function-aboveground net primary production (ANPP)-was 60% greater at sites that experienced statistically extreme drought (1-in-100-y event) vs. those sites where drought was nominal (historically more common) in magnitude (35% vs. 21%, respectively). This reduction in a key carbon cycle process with a single year of extreme drought greatly exceeds previously reported losses for grasslands and shrublands. Our global experiment also revealed high variability in drought response but that relative reductions in ANPP were greater in drier ecosystems and those with fewer plant species. Overall, our results demonstrate with unprecedented rigor that the global impacts of projected increases in drought severity have been significantly underestimated and that drier and less diverse sites are likely to be most vulnerable to extreme drought