Effects of resource availability and propagule supply on native species recruitment in sagebrush ecosystems invaded by Bromus tectorum

Biological Invasions
By: , and 

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Abstract

Resource availability and propagule supply are major factors influencing establishment and persistence of both native and invasive species. Increased soil nitrogen (N) availability and high propagule inputs contribute to the ability of annual invasive grasses to dominate disturbed ecosystems. Nitrogen reduction through carbon (C) additions can potentially immobilize soil N and reduce the competitiveness of annual invasive grasses. Native perennial species are more tolerant of resource limiting conditions and may benefit if N reduction decreases the competitive advantage of annual invaders and if sufficient propagules are available for their establishment. Bromus tectorum, an exotic annual grass in the sagebrush steppe of western North America, is rapidly displacing native plant species and causing widespread changes in ecosystem processes. We tested whether nitrogen reduction would negatively affect B. tectorum while creating an opportunity for establishment of native perennial species. A C source, sucrose, was added to the soil, and then plots were seeded with different densities of both B. tectorum (0, 150, 300, 600, and 1,200 viable seeds m-2) and native species (0, 150, 300, and 600 viable seeds m-2). Adding sucrose had short-term (1 year) negative effects on available nitrogen and B. tectorum density, biomass and seed numbers, but did not increase establishment of native species. Increasing propagule availability increased both B. tectorum and native species establishment. Effects of B. tectorum on native species were density dependent and native establishment increased as B. tectorum propagule availability decreased. Survival of native seedlings was low indicating that recruitment is governed by the seedling stage.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Effects of resource availability and propagule supply on native species recruitment in sagebrush ecosystems invaded by Bromus tectorum
Series title Biological Invasions
Volume 13
Issue 2
Year Published 2011
Language English
Publisher Springer
Publisher location Netherlands
Contributing office(s) Forest and Rangeland Ecosystem Science Center
Description 14 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Biological Invasions
First page 513
Last page 526
Other Geospatial North America