Sedgwick Reserve

19 Jan, 01 AM - 19 Jan, 06 AM

The ability of an introduced plant to successfully spread and become abundant depends in part on its interactions with arbuscular mycorrhizal fungi (AMF). Connections between plants and AMF are easily disrupted when soils are mechanically disturbed by agricultural processes such as tillage. Soil disturbances are common occurrences in California grasslands, where nearly 9.2 million hectares once dominated by native perennial grasses and annual forbs have become dominated by species of invasive annual grass from Eurasia. These annual grasses evolved with a history of agricultural disturbance in their native Eurasian habitats, perhaps pre-adapting them to readily invade mechanically disturbed sites here. Formerly tilled grassland sites in California do not return to native grass dominance even decades following disturbance. It is possible that the AMF associated with roots of annual grasses may be more resilient to tillage than those associated with the roots of native perennial grass species, and that agricultural practices select for AMF that disproportionately benefit invasive annual grasses. Knowledge of how plants, soils, and AM fungi interact is essential to a full understanding of the causes and consequences of plant invasion. As a first step towards understanding the role of AMF in influencing grassland composition and restoration, I will start with a comparative study of fungal colonization of grass roots in soils of different tillage history. I plan to select paired tilled and untilled grassland sites at Sedgwick Reserve. Because fungal communities are expected to change seasonally, root samples from native and non-native grasses will be collected from each field site at several times during the year. Individual grasses will be identified to species in the field prior to sampling. In the lab, plant roots will be separated from soils. Half of each root sample will be used to measure the frequency of AM fungal colonization of the grass roots with the ?magnified intersections method?. The other half of each sample will be used to assess changes in the AM fungal community using DNA-based characterization. Once I have documented different AM fungi in the different soils and plant roots, I will begin to amplify different fungal communities from the tilled and untilled soils in the greenhouse so that I can grow European annual species and native California grasses in combination with known fungal innocula in a controlled setting. This will allow me to evaluate how fungal community type affects growth rates of the two different types of grasses found in this region.

Visit #11671 @Sedgwick Reserve

Approved

Under Project # 7679 | Research

The role of plant-fungi symbioses in furthering California grassland invasion

research_scientist - University of California, Santa Barbara

Reservation Members(s)

Sophie Parker Jan 19, 2007 (1 days)
Sophie Parker Jan 19, 2007 (1 days)

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