The influence of roads on small mammal ecology in the north-west of Sydney
M.Sc.(Env) 1999
Ecological processes operating within formally protected nature reserves, or
within specific blocks of habitat, shape the biota of these areas through time.
Managers must be keenly aware of ecological processes operating within these
areas, such as population stochasticity, if they are to maintain resident biodiversity.
Yet, phenomena originating outside these boundaries strongly influence the fate
of the resident biota. This complicates the manager's job greatly, since it
implies a need for awareness and responsibility for biological events occurring
in much larger portions of the landscape. During the last two decades, these
often deleterious influences have come to be known as edge effects. This study
attempts to define such edge effects (in relation to roads) on the remnant forest
systems in the north-west of Sydney, New South Wales.
The influence of various road densities on the ecology of small mammals within the Local Council of Hornsby was examined. Significantly fewer small mammals were captured, in Elliott traps, in habitat directly adjacent to all roads (0-50m), in comparison to distance greater than 100 metres from roads and at control sites located away from such influences. However, analysis of hair traps, indicated that both species may utilise the road verges for foraging but are more circumspect and will not venture into live traps readily. Moreover, open space seems to be the major inhibitor for movement in these species, where both were strongly associated with vegetation cover. Additionally, a negative association with leaf litter was apparent in both species as leaf litter was related to a decrease in the amount of cover over a trap site.
Antechinus stuartii and Rattus fuscipes indicated, as representatives of biodiversity within remnant forest reserves and roadside verges, that the negative impact of anthropogenic influence related to the construction and usage of roads in the north-west of Sydney, creates a effect zone greater than 100 metres in depth adjacent to roads. These results may then imply that managers need to implement conservation measures to ensure that core habitat and corridor systems, in the Hornsby district, must have buffer zones greater than 100 metres to reduce the impact of roads and other constructed linear features within the urban landscape.