Dr Edward Ayres

Dr Edward Ayres

Research Scientist

Natural Resource Ecology Laboratory,

Colorado State University, Fort Collins, CO 80523-1499, USA

Tel: (+1) 970 491 1984 Fax: (+1) 970 491 1965

Selected publications

Steltzer H, Landry C, Painter TH, Anderson J, Ayres E (2009) Biological consequences of earlier snowmelt from desert dust deposition in alpine landscapes. Proceedings of the National Academy of Sciences 106, 11629–11634. Highlighted in Nature 460, 154. (pdf)

Ayres E, Steltzer H, Berg S, Wall DH (2009) Soil biota accelerate decomposition in high elevation forests by specializing in the breakdown of litter produced by the plant species above them. Journal of Ecology 97, 901-912. (pdf)

Ayres E, Steltzer H, Simmons BL, Simpson RT, Steinweg JM, Wallenstein MD, Mellor N, Parton WJ, Moore JC, Wall DH (2009) Home-field advantage accelerates leaf litter decomposition in forests. Soil Biology and Biochemistry 41, 606-610. (pdf)

Ayres E, Dromph KM, Cook R, Ostle N, Bardgett RD (2007) The influence of below-ground herbivory and defoliation of a legume on nitrogen transfer to neighbouring plants. Functional Ecology 21, 256-263. Winner of JBS Haldane Prize. (pdf)

Heath J, Ayres E, Possell M, Black HIJ, Bardgett RD, Ineson P, Kerstiens G (2005) Rising atmospheric CO₂ reduces sequestration of root-derived soil carbon. Science 309, 1711-1713. (pdf)

Ayres E, Heath J, Possell M, Black HIJ, Kerstiens G, Bardgett RD (2004) Tree physiological responses to aboveground herbivory directly modify belowground C and N cycling. Ecology Letters 7, 469-479. Highlighted in Science 304, 1567. (pdf)

Research and interests

My research focuses on interactions and feedbacks among plant, soil, and soil biota in relation to community composition and ecosystem processes. Current and former research projects are outlined below.

Home advantage and decomposition

Home advantage is common in various sports. We investigated home advantage in relation to leaf litter decomposition, i.e. do leaves decompose faster when in a area of plants of the same species versus a area of plants belonging to a different species, and showed that home advantage accelerates decomposition in most forests (Soil Biology and Biochemistry 41, 606-610). We also tested the hypothesis that soil communities beneath different plant species specialize in the rapid decomposition of litter from their 'host' plant species in a simple microcosm study (Soil Biology and Biochemistry 38, 183-186). Recently we established a field experiment in southern Colorado, USA, to further investigate these ideas under more realistic conditions (Journal of Ecology 97, 901-912). Ed Ayres (PI), Heidi Steltzer, Diana Wall, Breana Simmons, and Matt Wallenstein. Funded by the British Ecological Society and US National Science Foundation. (pdf 1, pdf 2, & pdf 3)

Global patterns of soil biodiversity and ecosystem function

Belowground communities probably account for more species, biomass and individuals than aboveground communities. However, little is known about the global-scale distribution of soil organisms. We do not know if the number of species living in soils increases towards the equator (as it does for most aboveground taxa) or if hotspots of aboveground diversity coincide with belowground hotspots. In this $1.2 million NSF-funded project we are sampling soils from a range of sites around the globe (N & S America, Europe, Africa, Australasia and Antarctica) and measuring their species richness, as well as physical and chemical properties. Early results confirm the large diversity of soil animals (Soil Biology and Biochemistry 41, 849–857). Diana Wall (PI), Jim Garey, Richard Bardgett, Tiehang Wu, and Ed Ayres. [Global Soil Biodiversity website] (pdf)

Rising CO₂ concentrations and carbon sequestration in soils

Sequestering carbon from the atmosphere represents an important mechanism for minimizing climate change. We tested whether a range of tree species enhance the sequestration of carbon in soils when exposed to elevated atmospheric CO₂. Despite increased carbon uptake by the trees, soil carbon sequestration declined in response to elevated CO₂ due to a stimulation of microbial respiration (Science 309, 1711-1713). If forests respond similarly, this feedback has the potential to accelerate the buildup of CO₂ in the atmosphere. Gerhard Kerstiens (PI), Phil Ineson, Richard Bardgett, Helaina Black, James Heath, Malcolm Possell, Ed Ayres. Funded by the UK Natural Environment Research Council (NERC). (pdf)

Soil organic nitrogen and grassland biodiversity

It is not always apparent how so many plant species can co-exist within a small area. Resource partitioning represent one way in which the co-existence of species can be maintained indefinitely. Different chemical forms of soil nitrogen may allow plants species to co-occur with minimal competition provided each species uses a different type of nitrogen. Using 15N-labeled nitrate, ammonium and a range of amino acids we are investigating the source of nitrogen for several plants species and soil microbes in a montane grassland in Scotland. Richard Bardgett (PI), Rene van der Wal, Ed Ayres. Funded by the UK Natural Environment Research Council (NERC).

Nitrogen uptake by mosses

Mosses are thought to acquire their nitrogen from the atmosphere via deposition. However, many moss species have a root-like structures that penetrate the soil potentially providing them with access to soil nitrogen. We used 15N labeled nitrate and ammonium to show that two contrasting moss species are able to take up soil inorganic nitrogen, suggesting that soil nitrogen uptake may be common among mosses (Biology Letters 2, 286-288). Since many terrestrial ecosystems are nitrogen limited, nitrogen uptake by mosses could have consequences for plant community structure. Richard Bardgett (PI), Rene van der Wal, Martin Sommerkorn, and Ed Ayres. Funded by the UK Natural Environment Research Council (NERC). (pdf)

Aboveground herbivory and belowground nutrient cycling

Large mammalian herbivores can consume a sizable proportion of plant productivity. However, herbivory can actually stimulate plant productivity and photosynthesis. We have shown that physiological changes in beech trees subjected to sustained defoliation enhances soil nitrogen availability allowing the trees to increase productivity and rates of photosynthesis over several growing seasons (Ecology Letters 7, 469-479). Gerhard Kerstiens (PI), Richard Bardgett, James Heath, Malcolm Possell, Helaina Black, Ed Ayres. Funded by the UK Natural Environment Research Council (NERC). (pdf)

Plant-plant and plant-microbe nutrient transfer

Grassland plant species compete for soil nutrients with each other and with soil microbes. We are testing the influence of aboveground defoliation, root herbivory, mycorrhizal colonization and soil faunal community structure on the outcome of these competitive interactions using 15N and 13C tracers. Richard Bardgett (PI), Karsten Dromph, Nick Ostle, Roger Cook, and Ed Ayres. Funded by the UK Biotechnology and Biological Sciences Research Council (BBSRC). See Functional Ecology 21, 256-263. (pdf)

Publications

Nielson UN, Ayres E, Wall DH, Bardgett RD (Submitted) Soil biodiversity and carbon cycling: a synthesis of studies examining diversity-function relationships. European Journal of Soil Science.

Ayres E, Nkem JN, Wall DH, Adams BJ, Barrett JE, Simmons BL, Virginia RA, Fountain AG (Submitted) Experimentally increased snow accumulation alters soil moisture and animal community structure in a polar desert. Polar Biology.

Wallenstein MD, Hess A, Lewis MR, Steltzer H, Ayres E (Submitted) High resolution liquid chromatography-mass spectrometry reveals that decomposed aspen leaf litter metabolomes differ when decomposed under different tree species. Soil Biology and Biochemistry.

Perry LG, Rieder JP, Dayakar BV, Ayres E, Wall DH, PaschkeMW, Vivanco JM (Submitted) Effects of soil microbial communities on six Arabidopsis thaliana genotypes. Plant, Cell and Environment.

Ayres E, Wall DH, Bardgett RD (in press) Trophic interactions and their implications for soil carbon fluxes. In: Integrated methodology on soil carbon flux measurements (eds. Bahn M, Heinemeyer A, Kutsch W). Cambridge University Press, Cambridge.

Simmons BL, Wall DH, Adams BJ, Ayres E, Barrett JE, Virginia RA (2009) Terrestrial mesofauna in above- and below-ground habitats: Taylor Valley, Antarctica. Polar Biology 32, 1549-1558. (pdf)

Simmons BL, Wall DH, Adams BJ, Ayres E, Barrett JE, Virginia RA(2009) Long-term experimental warming reduces soil nematode populations in the McMurdo Dry Valleys, Antarctica. Soil Biology and Biochemistry 41, 2052-2060. (pdf)

Ayres E, Steltzer H, Berg S, Wallenstein MD, Simmons BL, Wall DH (2009) Tree species traits influence soil physical, chemical, and biological properties in high elevation forests. PLoS ONE 4, e5964. (pdf)

Wu T, AyresE, LiG, BardgettRD, WallDH, Garey JR (2009) Molecular profiling of soil animal diversity in natural ecosystems: incongruence of molecular and morphological results. Soil Biology and Biochemistry 41, 849–857. (pdf)

Ayres E, Nkem JN, Wall DH, AdamsBJ, BarrettJE, BroosEJ, ParsonsAN, PowersLE, SimmonsBL, Virginia RA (2008) Human trampling reduces soil faunal populations in a polar desert, McMurdo Dry Valleys, Antarctica. Conservation Biology 22, 1544-1551. (pdf)

Ayres E, Wall DH, Simmons BL, Field CB, Milchunas DG, Morgan JA, Roy J (2008) Belowground nematode herbivores are resistant to elevated atmospheric CO₂ concentrations in grassland ecosystems. Soil Biology and Biochemistry 40, 978-985. (pdf)

Ayres E, Wall DH, Adams B, Barrett JE, Virginia RA (2007) Unique similarity of faunal communities across aquatic–terrestrial interfaces in a polar desert ecosystem. Ecosystems 10, 523-535. (pdf)

Ayres E, Dromph KM, Cook R, Ostle M, Bardgett RD (2007) The influence of below-ground herbivory and defoliation of a legume on nitrogen transfer to neighbouring plants. Functional Ecology 21, 256-263. Winner of JBS Haldane Prize. (pdf)

Ojima DS, Wall DH, Moore J, Galvin K, Hobbs NT, Hunt WH, Paustian K, Swift D, Boone RB, Conant RT, Klein J, Christensen L, Sankaran M, Ratnam J, Ayres E, Steltzer H, Simmons B, Williams G (2006) Don’t sell social science short. Science 312, 1470. (pdf)

Adams B, Bardgett RD, Ayres E, Wall DH, Aislabie J, Bamforth S, Bargagli R, Cary C, Cavacini P, Connell P, Convey P, Fell J, Frati F, Hogg I, Newsham K, O'Donnell T, Russell N, Seppeldt R, Stevens M (2006) Diversity and distribution of Victoria Land biota. Soil Biology and Biochemistry 38, 3003-3018. (pdf)

Ayres E, Van der Wal R, Sommerkorn M, Bardgett RD (2006) Direct uptake of soil nitrogen by mosses. Biology Letters 2, 286-288. (pdf)

Ayres E, Dromph KM, Bardgett RD (2006) Do plant species encourage soil biota that specialise in the rapid decomposition of their litter? Soil Biology and Biochemistry 38, 183-186. (pdf)

Heath J, Ayres E, Possell M, Black HIJ, Bardgett RD, Ineson P, Kerstiens G (2005) Rising atmospheric CO₂ reduces sequestration of root-derived soil carbon. Science 309, 1711-1713. (pdf)

Wall DH, Ayres E, Behan-Pelletier V, Covich A, Snelgrove PVR (2005) Soils, freshwater and marine sediments: the need for integrative landscape science. In: Bridging the gap between aquatic and terrestrial ecology (eds. Stergiou KI, Browman HI). Marine Ecology Progress Series 304, 302-307. (pdf)

Possell M, Hewitt N, Heath J, Ayres E, Kerstiens G (2004) Interactive effects of elevated CO₂ and soil fertility on isoprene emissions from Quercus robur. Global Change Biology 10, 1835-1843. (pdf)

Links

Ed Ayres - NREL website

Ed Ayres - Researcher-ID website

Natural Resource Ecology Laboratory

Colorado State University