population structure

Urban reserves have the potential to retain relatively high biodiversity. However, populations of the taxa within them can have reduced genetic diversity and, if gene flow between populations is inhibited by urbanised surroundings, can become genetically differentiated. Here we determine whether differences in population genetic differentiation and diversity can be observed in the leaf litter inhabiting weevil Geochus politus along the urban-rural gradient spanning Waitākere Ranges Regional Parkland and suburbs of west Auckland, New Zealand.

The influence of water movement on sponge population structure was investigated in the marine sponge Ancorina corticata (Carter) from Westernport Bay, Victoria, Australia. Population characteristics studied were dispersion, population density, biomass and size-frequency distributions. Strong continuous water movement facilitated the growth of the sponge but no effects were found on the dispersion patterns of the population

Over five years from November 1982 to November 1987, we examined 395 mice collected from unlogged and logged native forest and from exotic forest at Pureora Forest Park, in the central North Island of New Zealand. Sex ratio, litter size, and breeding effort (pregnancy rate in females, proportion of males with visible tubules) were similar in all samples.

Population size and structure of 52 isolated Nothofagus fusca stands were investigated in the lower Otira Valley, 3-6 km from a major population centre in the upper Taramakau catchment. The approximate age of N. fusca pioneer trees, estimated from partial increment cores and calculations based on diameter growth rates, indicated that nearly all isolated stands originated after 1600 AD, predominantly during the periods 1600-1760 AD and 1865-1910 AD.