seed dispersal

Fleshy fruits of indigenous and adventive plants in the diet of birds in forest remnants, Nelson, New Zealand

The relationship between fleshy-fruited indigenous species and adventive weeds in the diet of 500 mist-netted birds was studied in forest remnants of differing size and degree of modification. Fruit abundance Peaked in March and April, and most fruit was either red/orange or purple/black. The physical parameters of adventive and indigenous fruits were not significantly different. Six of the 15 passerine species netted are frugivores, and of those netted 77% had eaten fruit.

Dispersal, germination and survival of New Zealand mistletoes (Loranthaceae): Dependence on birds

The dispersal, germination and establishment of the New Zealand Loranthaceae (Alepis flavida, Peraxilla colensoi, P. tetrapetala, Ileostylus micranthus and Tupeia antarctica) were investigated. The most important bird dispersers were tui, bellbirds and silvereyes. These birds appear to provide reasonably good quality dispersal: fruits were swallowed whole and the seeds later defecated in germinable condition; birds tended to visit plants for only 1-2 minutes and eat a few mistletoe fruits each time.

Seed rain and soil seed banks limit native regeneration within urban forest restoration plantings in Hamilton City, New Zealand

Restoration of native forest vegetation in urban environments may be limited due to isolation from native seed sources and to the prevalence of exotic plant species. To investigate urban seed availability we recorded the composition of seed rain, soil seed banks and vegetation at native forest restoration plantings up to 36 years old in Hamilton City and compared these with naturally regenerating forest within the city and in a nearby rural native forest remnant.

Impacts of introduced deer and extinct moa on New Zealand ecosystems

There has been considerable ongoing debate about the extent to which the impacts of introduced deer on native vegetation have replaced those of moa, and since the 1980s there have been major changes in thinking about the impacts of deer and ratites on ecosystems. Although it has long been known that deer caused a predictable sequence of changes in forest understorey composition, recent work has shown that the foliage of species preferred by deer contains lower concentrations of fibre – and decomposes faster – than avoided species.

Dietary diversity in fruit-eating birds: a biogeographic comparison between New Zealand and Canada

If deterministic processes consistently structure ecological communities, similar patterns in species interactions should be observed in different geographic areas that experience similar environmental conditions. I tested for convergent patterns in dietary diversity of fruit-eating birds inhabiting similar latitude forests in the Northern and Southern hemispheres. I observed birds foraging for fruits over two fruiting seasons in both Nelson Lakes National Park, South Island, New Zealand, and the Pacific Rim National Park, Vancouver Island, Canada.

When is it coevolution? The case of ground wētā and fleshy fruits in New Zealand

Both tree and ground wētā have been proposed as potential seed dispersers of some New Zealand fruit. We examine evidence for coevolution of ground wētā and fleshy fruits as suggested by Burns (2006). We found that although ground wētā consume fruits from Gaultheria depressa and G. antipoda, they do not do so in a way that would suggest they had coevolved as dispersers with these or other New Zealand plants (Coprosma, Muehlenbeckia, Leucopogon).

Seed retention times in the New Zealand pigeon, Hemiphaga novaeseelandiae

We offered ripe fruits of tawa (Beilschmiedia tawa), taraire (B. tarairi), and pūriri (Vitex lucens) to captive New Zealand pigeons (Hemiphaga novaeseelandiae) and recorded seed retention times. We also recorded seed retention times while radio-tracking wild pigeons in Taranaki and Canterbury. We report wild pigeon retention times for tawa, pūriri, miro (Prumnopitys ferruginea), fivefinger (Pseudopanax arboreus), and kahikatea (Dacrycarpus dacrydioides) seeds.