Climatic niche shifts are common in introduced plants.
I am very excited to announce that our paper has just been accepted for publication by Nature: Ecology & Evolution. In it, we show that almost 1000 invasvie plant species occupy much different climates in their introduced range than in their native range.
This finding is significant for several reasons. First, it means that species do not necessarily occupy the same environments everywhere they are found on Earth. Second, it casts doubt on the viability of using information about species’ native-range habitat preferences to predict where they will invade.
However, we found that niche shifts depended upon species growth form, life expectancy, and degree of cultivation, suggesting that ‘niche shifts’ might be predictable.
Particular congratulations go to Carissa Ervine, who contributed to this manuscript as an undergraduate student. She was responsible for assembling the first version of our database of 13 million occurrence records for 1135 species–a major undertaking!
Competition and propagule density affect sexual and clonal propagation of a weed.
Atwater, Kim, Tekiela, Barney
This study was pioneered by Wonjae Kim, an undergraduate student at Virginia Tech who designed and executed it on a grant from the Fralin Life Sciences Institute.
Wonjae confirmed that Johnsongrass establishes readily both from seed and from buried rhizome fragments, although these two modes of reproduction differed in their sensitivity to competition and soil quality. In fact, a single plant produces enough seeds and rhizomes to establish over more than a hectare (if spread out evenly)!
Wonjae’s results show that effective management of Johnsongrass must limit spread from both seeds and underground rhizomes.
A great way to ring in the new year!
An exotic invasive plant selects for increased competitive tolerance, but not competitive suppression, in a native grass
Fletcher, Callaway & Atwater (pdf)
Many congratulations to Rebecca Fletcher, who just had a paper accepted into Oecologia. Her paper shows that spotted knapweed, an invasive plant, selects for bluebunch wheatgrass plants that are tolerant of knapweed competition, but not for ones that are better at competitively suppressing knapweed.
This is the first direct test of the hypothesis that neighbor suppression does not provide fitness benefits to competing plants. Her finding is important because it challenges long-held notions of what makes a plant a good competitor. Becky performed this research as an undergraduate student at the University of Montana, on a grant she wrote for the Montana Integrative Research Experience for Students (MILES) program.
Propagule pressure alone cannot always overcome biotic resistance: The role of density-dependent establishment in four invasive species
Barney, Ho & Atwater (link)
I am very pleased to announce that we have just had a paper accepted for publication into Weed Research. This paper documents Master’s Student Matt Ho’s research into the role of propagule pressure in invasion. He found that negative density-dependent germination probability causes diminishing returns for species that broadcast a large number of seeds. His results suggest that site conditions and species interactions play an important role in determining invasion probability even when propagule pressure is intense.
I recently presented the results of my niche modeling work at the 2016 Northeastern Plant Pest and Soils Conference in Philadelphia. I went the the conference along with most of the rest of my postdoc advisor’s (Jacob Barney’s) lab and we had a great time. I met a lot of people, including the First American, Benjamin Franklin, who looked great despite being only a week away from his 310th birthday.
At the conference, I presented the results of our study of climatic niche shifts in introduced species. Jacob and I have found that species experience major niche shifts as they cross continents. This work is in preparation for submission.
Also, congratulations are in order for “Little” Dan Tekiela, who won the Robert D. Sweet Outstanding Graduate Student Award and placed first in the Student Paper Contest. Virginia Tech also won the NEPPSC quiz bowl, besting teams from Cornell, Penn State, UMass, Maine, NC State, and Delaware, as well as the EB-ESA Linnaean Games. Graduate students Morgan Franke and Dan Tekiela both gave excellent presentations of their research.