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New paper in ‘Ecology’

Testing the mechanisms of diversity-dependent overyielding in a grass species

Atwater & Callaway (2016)(link)
007-boxplotsEDI’m very pleased to announce that Ray Callaway and I have just had a paper published in Ecology. In this paper, we find that genetically diverse populations of bluebunch wheatgrass (Pseudoroegneria spicata) yield about 50% more biomass than populations with low diversity.

This diversity-dependent “overyielding” is thought to occur because diverse plant communities function more efficiently than communities with low diversity. There is thought to be less demand for shared resources in diverse communities and less disease (e.g. by soil fungi). As a result, overyielding in species-diverse communities is often associated with changes in soil nutrients, and the yield of low-diversity communities can be “rescued” by killing soil pathogens.

However, we find that diversity-dependent overyielding in bluebunch wheatgrass populations was not related to changes in soil nutrients, and was unaffected by fungicide applied to the soil. We conclude that overyielding in genetically diverse populations may not be caused by the same processes that cause overyielding of species diverse communities.

 

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New Paper in ‘AoB: Plants’

Root contact responses and the positive relationship between intraspecific diversity and ecosystem productivity

Yang, Callaway & Atwater (2015) (link)

When grown next to a familiar neighbor, Johnsongrass root growth was initially rapid, but slowed when root contact occured. The opposite was true for plants grown next to an unfamiliar neighbor.

I’m very pleased to announced that Lixue’s manuscript has just been accepted by Annals of Botany: Plants.

In this paper, we find that bluebunch wheatgrass (Pseudorogneria spicata) plants are able to recognize the identity of their neighbors even before their roots touch. The rate of their growth depends on the familiarity of their neighbor.

These exciting results suggest that plants can sense and respond to their neighbors both before and after root contact has occurred, and that neighbor recognition may play a very important role in determining the outcome of competition.

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WSSA 2015 – Lexington

022-JGUltra-Ecography-Fig-A5

Two phases of invasion: Initial invasion (red) appears to have been in warmer climates. Later in invasion (blue) Johnsongrass has expanded to cooler climates.

On Thursday, at the Weed Science Society of America meeting in Lexington, I presented the results of a large scale survey of phenotypic differentiation in 499 accessions of Johnsongrass (Sorghum halepense) from 70 populations throughout the United States. Jacob Barney — my postdoctoral advisor — was initially scheduled to present, but I took his place when a scheduling conflict prevented his attendance.

I had a great meeting and met a lot of wonderful people. Special congratulations to Kate Venner, Sandeep Rana, and John Brewer from the lab upstairs for their recognitions and accomplishments at the meeting.