Document Type

Article

Publication Title

American Journal of Botany

Publication Date

8-2015

Abstract

PREMISE OF THE STUDY: Shade tolerance is a key trait promoting invasive plant performance in forest interiors. Rosa multifl ora is a problematic invasive shrub in the northeastern United States, occurring in edge habitats and encroaching into forests. Our objective was to evaluate the shade tolerance of R. multifl ora to assess how ecophysiological traits may facilitate its spread into forest interiors. METHODS: In the fi eld, we documented shrub and seed bank density, fecundity, phenology, and seasonal photosynthetic rates of R. multifl ora in contrasting light environments. In the greenhouse, we exposed seedlings to simulated canopy treatments by altering spectral quantity and quality, mimicking habitats ranging from open fi elds to forest interiors.

KEY RESULTS: In the fi eld, shrub density and fecundity of R. multifl ora sharply increased with light availability. However, no diff erences were observed between forest edge and interior seed banks. Rosa multifl ora initiated leaf growth earlier and retained leaves longer than canopy vegetation and tended to have higher photosynthetic rates in spring and fall. In the greenhouse, plants displayed shade-avoidance traits, decreasing relative growth rate and reducing branching, while increasing elongation and showing no change in light response curve parameters.

CONCLUSIONS: In deciduous forest understories, R. multifl ora appears to make use of a lengthened growing season in spring and fall, and therefore, substantial growth and spread through intact forests appears dependent on canopy gaps. Management should focus on reducing edge populations to reduce spread into the interior and on monitoring newly created canopy gaps.

Comments

doi:10.3732/ajb.1500115

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