shade

Recruitment failure of native plants is common in dryland ecosystems in New Zealand. We investigated whether herbicide control of invasive grasses or restoration of either shrub cover or the natural disturbance regime (river gravel deposition after flooding) can promote seedling establishment of the critically endangered shrub Olearia adenocarpa and two common species also found in river floodplain ecosystems (Carmichaelia australis and Sophora microphylla).

Tradescantia fluminensis, commonly referred to as ‘tradescantia’, is an invasive weed of canopydepleted forest remnants. Previous research suggests that a reduction of tradescantia biomass to ~80 gm-2 (~40% cover) is compatible with native forest regeneration. I assessed herbicide application, hand weeding and artificial shading as methods for the control of tradescantia in two lowland podocarp/broad-leaved forest remnants in the lower North Island of New Zealand.