THOMAS L. POWELL results 29
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Climate change may alter phenology within populations with cascading consequences for community interactions and on‐going evolutionary processes. Here, we measured the response to climate warming in two sympatric, recently diverged (~170 years) populations of Rhagoletis pomonella flies specialized on different host fruits (hawthorn and apple) and their parasitoid wasp communities. We tested whether warmer temperatures affect d...
SNAPSHOT USA 2020: A second coordinated national camera trap survey of the United States during the COVID ‐19 pandemicNARA Subscribed
Managing wildlife populations in the face of global change requires regular data on the abundance and distribution of wild animals, but acquiring these over appropriate spatial scales in a sustainable way has proven challenging. Here we present the data from Snapshot USA 2020, a second annual national mammal survey of the USA. This project involved 152 scientists setting camera traps in a standardized protocol at 1485 location...
Divergent adaptation to new ecological opportunities can be an important factor initiating speciation. However, as niches are filled during adaptive radiations, trait divergence driving reproductive isolation between sister taxa may also result in trait convergence with more distantly related taxa, increasing the potential for reticulated gene flow across the radiation. Here, we demonstrate such a scenario in a recent adaptive...
Prolonging survival in good health is a fundamental societal goal. However, the leading determinants of disability-free survival in healthy older people have not been well established. Data from ASPREE, a bi-national placebo-controlled trial of aspirin with 4.7 years median follow-up, was analysed. At enrolment, participants were healthy and without prior cardiovascular events, dementia or persistent physical disability. Disab...
Functional traits offer a rich quantitative framework for developing and testing theories in evolutionary biology, ecology and ecosystem science. However, the potential of functional traits to drive theoretical advances and refine models of global change can only be fully realised when species‐level information is complete. Here we present the AVONET dataset containing comprehensive functional trait data for all birds, includi...
Long‐term change in the avifauna of undisturbed Amazonian rainforest: ground‐foraging birds disappear and the baseline shiftsNARA Subscribed
How are rainforest birds faring in the Anthropocene? We use bird captures spanning > 35 years from 55 sites within a vast area of intact Amazonian rainforest to reveal reduced abundance of terrestrial and near‐ground insectivores in the absence of deforestation, edge effects or other direct anthropogenic landscape change. Because undisturbed forest includes far fewer terrestrial and near‐ground insectivores than it did histori...
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...
Numerous current efforts seek to improve the representation of ecosystem ecology and vegetation demographic processes within Earth System Models ( ESM s). These developments are widely viewed as an important step in developing greater realism in predictions of future ecosystem states and fluxes. Increased realism, however, leads to increased model complexity, with new features raising a suite of ecological questions that requi...
Differences in xylem and leaf hydraulic traits explain differences in drought tolerance among mature Amazon rainforest treesNARA Subscribed
Considerable uncertainty surrounds the impacts of anthropogenic climate change on the composition and structure of Amazon forests. Building upon results from two large‐scale ecosystem drought experiments in the eastern Brazilian Amazon that observed increases in mortality rates among some tree species but not others, in this study we investigate the physiological traits underpinning these differential demographic responses. Xy...
A test of genomic modularity among life‐history adaptations promoting speciation with gene flowNARA Subscribed
Speciation with gene flow may require adaptive divergence of multiple traits to generate strong ecologically based reproductive isolation. Extensive negative pleiotropy or physical linkage of genes in the wrong phase affecting these diverging traits may therefore hinder speciation, while genetic independence or “modularity” among phenotypic traits may reduce constraints and facilitate divergence. Here, we test whether the gene...
C hlorobaculum tepidum growth on biogenic S (0) as the sole photosynthetic electron donorNARA Subscribed
Summary The green sulfur bacteria, the C hlorobi , are phototrophic bacteria that oxidize sulfide and deposit extracellular elemental sulfur globules [ S (0)]. These are subsequently consumed after sulfide is exhausted. S (0) globules from a C hlorobaculum tepidum mutant strain were purified and used to show that the wild‐type strain of C ba. tepidum can grow on biogenic S (0) globules as the sole photosynthetic electron donor...
Experimental evidence of genome‐wide impact of ecological selection during early stages of speciation‐with‐gene‐flowNARA Subscribed
Theory predicts that speciation‐with‐gene‐flow is more likely when the consequences of selection for population divergence transitions from mainly direct effects of selection acting on individual genes to a collective property of all selected genes in the genome. Thus, understanding the direct impacts of ecologically based selection, as well as the indirect effects due to correlations among loci, is critical to understanding s...
Ecological speciation with gene flow may be an important mode of diversification for phytophagous insects. The recent shift of R hagoletis pomonella from its native host downy hawthorn ( C rataegus mollis ) to introduced apple ( M alus domestica ) in the northeastern U nited S tates is a classic example of sympatric host race formation. Here, we test whether R . pomonella has similarly formed host races on four native C rataeg...
This study reports the aboveground biomass response of a fire‐regenerated Florida scrub‐oak ecosystem exposed to elevated CO 2 (1996–2007), from emergence after fire through canopy closure. Eleven years exposure to elevated CO 2 caused a 67% increase in aboveground shoot biomass. Growth stimulation was sustained throughout the experiment; although there was significant variability between years. The absolute stimulation of abo...
We used eddy covariance and biomass measurements to quantify the carbon (C) dynamics of a naturally regenerated longleaf pine/slash pine flatwoods ecosystem in north Florida for 4 years, July 2000 to June 2002 and 2004 to 2005, to quantify how forest type, silvicultural intensity and environment influence stand‐level C balance. Precipitation over the study periods ranged from extreme drought (July 2000–June 2002) to above‐aver...