Russell, J.C.; Clout, M.N. 2004. Modelling the distribution and interaction of introduced rodents on New Zealand offshore islands. Global Ecology and Biogeography 13: 497–507.
Invasion of New Zealand’s offshore islands by the four introduced rodents has caused widespread damage to the native biota. Here the geographical and ecological factors that relate to their distribution on offshore islands are examined, as are interactions between their distributions. The ship rat appears most widely distributed, and the most dominant, while kiore have suffered mostly from the expansion of ship rats and to a lesser extent Norway rats. The distribution of mice remains unexplained. Their coexistence is explained by differences in competitive ability and dispersal.
02 December, 2004
Gillman et al. (2004): The influence of macro-litterfall and forest structure on litterfall damage to seedlings.
Gillman, L.N.; Ogden, J.; Wright, S.D.; Stewart, K.L.; Walsh, D.P. 2004. The influence of macro-litterfall and forest structure on litterfall damage to seedlings. Austral Ecology 29: 305–312.
Litterfall damage to forest seedlings can differentially affect the survival and recruitment of different seedling species and it is therefore likely to influence forest composition. Rates of damage to seedlings differ among, and within, forests and appear to be independent of total litterfall. However, in this study of five North Island forests we demonstrate that the rate of macro-litterfall (leaf and deadwood material >1.5 x 30cm) surface area correlates strongly to litterfall damage to artificial seedlings (R2 = 0.99, P<0.005). In addition, the risk of litterfall damage to seedlings was reduced by up to 84% by ground vegetation and lianes. These results are important because they suggest that subtle differences in species abundances, and forest structure, may influence regeneration patterns through the litterfall disturbance regime.
Litterfall damage to forest seedlings can differentially affect the survival and recruitment of different seedling species and it is therefore likely to influence forest composition. Rates of damage to seedlings differ among, and within, forests and appear to be independent of total litterfall. However, in this study of five North Island forests we demonstrate that the rate of macro-litterfall (leaf and deadwood material >1.5 x 30cm) surface area correlates strongly to litterfall damage to artificial seedlings (R2 = 0.99, P<0.005). In addition, the risk of litterfall damage to seedlings was reduced by up to 84% by ground vegetation and lianes. These results are important because they suggest that subtle differences in species abundances, and forest structure, may influence regeneration patterns through the litterfall disturbance regime.
Efford (2004): Density estimation in live-trapping studies.
Efford, M.G. 2004. Density estimation in live-trapping studies. Oikos 106: 598–610.
This paper describes a new and general method for estimating density from closed-population capture–recapture data. Simulation and inverse prediction are used to estimate jointly the population density and two parameters for a spatial model of detection. The method uses any configuration of traps (e.g., grid, web or line), and simulations show it is largely free of bias when simple assumptions are met. The paper includes two New Zealand examples: Landcare Research data on brushtail possums in the Orongorongo Valley, and Ross Pickard’s study of house mice on Mana Island. See www.landcareresearch.co.nz/services/software/density for software and a pdf of the paper.
This paper describes a new and general method for estimating density from closed-population capture–recapture data. Simulation and inverse prediction are used to estimate jointly the population density and two parameters for a spatial model of detection. The method uses any configuration of traps (e.g., grid, web or line), and simulations show it is largely free of bias when simple assumptions are met. The paper includes two New Zealand examples: Landcare Research data on brushtail possums in the Orongorongo Valley, and Ross Pickard’s study of house mice on Mana Island. See www.landcareresearch.co.nz/services/software/density for software and a pdf of the paper.
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