weed

Non-native conifers constitute a significant threat to the ecology and biodiversity of many of New Zealand’s native ecosystems and species. From the top down, the potential distributions of non-native conifer species are governed by climate suitability, which alongside variables such as the availability of suitable habitats and a source of propagules determines whether an area of land will be susceptible to invasion by a given species.

Cortaderia selloana (pampas grass) and C. jubata (purple pampas grass) are both invasive in New Zealand. Cortaderia selloana is found throughout most of the country, whereas C. jubata is restricted to the North Island and the northern South Island. We examine the genetic variation present in each of the species, and compare this to the findings of an earlier study that analysed the variation in invasive C. jubata plants from New Zealand.

Banana passionfruit (Passiflora tripartita var. mollissima) is a noxious vine that is invasive in forest patches in coastal regions throughout New Zealand. We investigated the dispersal mechanisms that facilitate its spread in the Marlborough Sounds. To find out which animals act as dispersers, we monitored tagged fruits in the field. Fruits were removed quickly after ripening.

Growth, sun/shade acclimation and nitrogen nutrition were examined in Tradescantia fluminensis to gain greater understanding of why this species is so successful in New Zealand native forest remnants. Over a two year period, the rate of shoot extension of T. fluminensis in a New Zealand mixed mahoe (Melicytus ramiflorus) coastal forest remnant showed a similar pattern to monthly mean values for mean daily air temperature and day length. Growth at the shoot apex was balanced by death at the shoot base.

We studied the genus- and species-specialist monophagous herbivorous insects of Senecio (Asteraceae) in Auckland, New Zealand. With the exception of the widespread S. hispidulus, the eight native Senecio species in mainland Auckland (two endemic) are typically uncommon and restricted to less modified conservation land. However, 11 naturalised Senecio have established and are often widespread in urban and rural habitats.