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United States Department of Agriculture

Agricultural Research Service

Research Project: REDUCING THE IMPACT OF INVASIVE WEEDS IN NORTHERN GREAT PLAINS RANGELANDS THROUGH BIOLOGICAL CONTROL AND COMMUNITY RESTORATION

Location: Pest Management Research Unit

Title: A colonizing species has high fitness on soils with an exotic species legacy when conditioning effects are mitigated

Author
item Espeland, Erin

Submitted to: Ecological Restoration
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2013
Publication Date: June 1, 2013
Repository URL: http://handle.nal.usda.gov/10113/57063
Citation: Espeland, E.K. 2013. A colonizing species has high fitness on soils with an exotic species legacy when conditioning effects are mitigated. Ecological Restoration. 31(2): 195-200.

Interpretive Summary: Plants change soils simply by growing in them. They deplete soils of nutrients, but also add nutrients back in the form of leaf litter and root decomposition. Plants can also change the biotic communities in the soil: affecting the species composition and abundance of soil fungi and bacteria and other microorganisms through root exudates. Plant effects on soils can either be short term (within-growing-season) soil conditioning or longer-term influences, called soil legacies. Soil conditioning and soil legacies can prevent effective restoration. Studies have shown that once invasive species are removed, harmful effects to natives can still be transmitted via soils. In this experiment, I compare the effects of soil conditioning from early- successional (native-dominated) and later- successional (exotic-dominated) communities of a California annual grassland on the performance of a colonizing native annual forb, California plantain. The successional status of the soil reflects its legacy: early-successional soils in this system have native species legacies and later-successional soils have both native and exotic species legacies. I experimentally removed soil conditioning effects by keeping plots clear for one year prior to seeding the experiment. The soil legacy of the later-successional community doubled California plantain fitness but only when soil conditioning effects were absent. While soil conditioning and soil legacies can impact restoration success, these effects may be mitigated by keeping areas clear from vegetation for one growing season prior to planting.

Technical Abstract: Plant interaction with soil can create feedbacks that influence intraspecific and interspecific performance. These feedbacks can either be short term, within-season soil conditioning called priority effects or longer-term influences called soil legacies. Soil conditioning and soil legacies can prevent effective restoration. In this experiment, I compare the effects of soil conditioning from early- (native-dominated) and later- (exotic-dominated) successional communities of a California annual grassland on the performance of a colonizing native annual forb, California plantain. At early- and later- successional locations, I compared California plantain fitness in areas that had been kept clear of vegetation starting early the previous growing season to fitness in areas that were cleared at the start of the current growing season. The soil legacy of the later-successional community doubled California plantain fitness compared to when soil conditioning from the later-successional community was present. While soil conditioning and soil legacies can impact restoration success, these effects may be mitigated by keeping areas clear from vegetation for one growing season prior to planting.

Last Modified: 8/29/2014