Interacting global change drivers suppress a foundation tree species.

Ecological stress caused by climate change, invasive species and anthropogenic disturbance is driving global environmental change, but how these stressors interact to impact native species are poorly understood. We used a field experiment to test how two stressors (drought and plant invasion by Imperata cylindrica) interacted to determine the effects of a third stressor (fire) on a foundation tree species (Pinus palustris). The invasion combined with prolonged drought resulted in shorter trees than invasion alone.

Populations of a widespread invader and co-occurring native species vary in phenotypic plasticity.

Phenotypic plasticity can promote plant invasions and enhance impacts on native species, but little is known about variation in plasticity among invader populations compared with native species. Variation in plasticity among invader populations could inform more precise predictions of invader spread and impacts across heterogeneous resource environments. We used a common garden experiment with sun and shade treatments to test for variation in plasticity among 12 populations of an invasive grass (Imperata cylindrica), and to determine whether the invader exhibited greater plasticity than six native species that co-occur in the Southeast USA.

Reduction of pupil size and halos with minus lenses after laser in situ keratomileusis.

Purpose: To evaluate the amount of miosis induced by over-minused lenses and to assess subjective reduction of halos following laser in situ keratomileusis (LASIK) with such lenses.

Methods: Part I: Infrared pupil diameter was assessed in 14 patients who had not had ocular surgery. The accommodative/miotic reflex was stimulated with concave trial lenses in -1.