The development of a plant risk evaluation (PRE) tool for assessing the invasive potential of ornamental plants.

Weed Risk Assessment (WRA) methods for evaluating invasiveness in plants have evolved rapidly in the last two decades. Many WRA tools exist, but none were specifically designed to screen ornamental plants prior to being released into the environment. To be accepted as a tool to evaluate ornamental plants for the nursery industry, it is critical that a WRA tool accurately predicts non-invasiveness without falsely categorizing them as invasive.

Predispersal seed predation is higher in a rare species than in its widespread sympatric congeners (Astragalus, Fabaceae).

Premise Of The Study: Rare plants may be rare, in part, because they are more susceptible to damage by predispersal insect seed predators than widespread congeneric species; thus, seed predation may be an important determinant of plant rarity. Scant evidence exists to either support or reject this hypothesis, limiting our ability to predict herbivore effects on plant rarity. We used a comparative framework to test this hypothesis in rare-common, sympatric congeners.

Invasive competitor and native seed predators contribute to rarity of the narrow endemic Astragalus sinuatus Piper.

The conservation of rare plant species hinges on our ability to identify the underlying mechanisms that limit rare plant populations. Theory on rarity suggests that both predispersal seed predation and competition can be important mechanisms influencing abundance and/or distribution of rare plant populations. Yet few studies have tested these interactions, and those that have evaluated each mechanism independently.

Biological invasions: recommendations for U.S. policy and management.

The Ecological Society of America has evaluated current U.S. national policies and practices on biological invasions in light of current scientific knowledge.