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Abstract Detail

Ecological Section

Carrigy, Alec [1], Stotz, Gisela [1], Dettlaff, Margarete [1], Pec, Greg [2], Singh, Inderjit [3], Erbilgin, Nadir [4], Cahill Jr., James F. [5].

Bromus inermis growth and survival in a savannah system.

Plant invasions pose one of the greatest threats to native plant communities worldwide and incur significant economic costs. However, not all natural systems are equally susceptible to invasion and identifying and characterizing factors associated with invasion pressure is important in management and mitigation of potential impacts. Here, we aim to identify the ecological conditions associated with an invasive species’ survival and growth in the aspen parkland, a unique system in the prairie provinces of Canada. Smooth brome (Bromus inermis) is a widespread and highly aggressive invader, whose spread results in decreases in native plant diversity, changes to bacterial soil communities, as well as nutrient cycling. Despite its negative consequences for native plant communities, smooth brome is actively being planted within agricultural systems, roadside ditches, and mine tailings ponds across Canada and elsewhere. To test community susceptibility to invasion, we planted smooth brome in four community types within the aspen parkland (native grasslands, smooth brome, aspen forest edge, and aspen forest interior) at 14 locations, comparing survival and biomass among the community types. Both survival and biomass were lowest in the smooth brome community type, uncovering an unusual invasion strategy: brome must spread in order to persist in this landscape. It has been suggested that diversity and the resources available within communities may explain invasion patterns; to test which community variables are associated with invasion pressure, we tested a series of general linear mixed models including a base model simply including community identity, as well as more complex models including biotic and abiotic factors alone and together. We found that including biotic and abiotic variables did not explain brome biomass any better than a simple model including entire community variation. Biotic variables explained survival as well as a simpler model including only community type. Overall, we found little support for resource availability or diversity mediating the invasibility of the aspen parkland communities. This suggests that either many factors are associated with invader growth and survival, or that some unmeasured variable drives survival and growth of brome in this system, but more research is needed here. Our results have clear conservation implications – that brome performs better when invading as opposed to existing within its own community type uncovers the need for clear management strategies and education regarding this species. These steps are vital in maintaining the integrity of the unique aspen parkland system.

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1 - University of Alberta, Biological Sciences, CW 405, Biological Sciences Building, Edmonton, AB, T6G2E9, Canada
2 - University Of Alberta, Department Of Biological Sciences, 11455 Saskatchewan Drive, Edmonton, AB, T6G 2E9, Canada
3 - University of Delhi, Environmental Sciences, Delhi-110007, Delhi, India
4 - University of Alberta, Renewable Resources, 751 General Services Building, Edmonton, AB, T6G2H1, Canada
5 - University Of Alberta, Department Of Biological Sciences, CW405 Bio Sci Bldg, Edmonton, AB, T6G 2E9, Canada

Bromus inermis

Presentation Type: Poster:Posters for Sections
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PEC034
Abstract ID:1249
Candidate for Awards:Ecological Section Best Undergraduate Presentation Award

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