| Abstract: | Previous studies have demonstrated a species replacement sequence in disturbed forest and heathland, with the native New Holland mouse (Pseudomys novaehollandiae) replacing the introduced house mouse (Mus musculus) in the earliest part of the succession. The replacement appeared to be competitive displacement and this has been confirmed by controlled experimental removal of P. novaehollandiae from field sites, which produced significant increases in the abundance and habitat use of Mus musculus. This paper reports the results of the controlled reciprocal manipulation experiment in the field. A pulsed addition of M. musculus to three treatment plots produced significant reductions in the abundance and habitat use of P. novaehollandiae, when compared with control plots with no addition of M. musculus. This effect was observed only at high M. musculus densities, and the return to the control conditions within 3 months of the pulsed addition is consistent with asymmetric interspecific competition from competitively superior P. novaehollandiae. The importance of considering the regional abundance of M. musculus in relation to its competitive ability is stressed, as at high densities M. musculus is able to create its own ecological space contrary to its more usual competitively submissive status. |
