Geography Reference
In-Depth Information
Fig. 7 Ringmap of seasonal and nightly patterns of habitat use (depicted by colours) by a male
common brushtail possum (#1882). Each ring represents a 10-min interval of time after sunset,
ordered outwards from the inner ring. Each sector represents one night starting from March 2007
and ending in February 2008. The inset timelines represent spatial movement paths. '0-12'
indicates hour after sunset
autumn. These observations further confirm the patterns shown in Fig.
7
. In both
seasons, there clearly is proportionally higher use of native and pine forests during
the early and late hours of the night, suggesting that this possum preferred to locate
its den sites in such habitats. Associated with a reduction in the proportional use of
these habitats during the middle hour of the night is an increase in the use of wet
native bush and grass, preferred foraging areas.
As discussed earlier, ringmaps provide a compact and powerful means of
visualising cyclic phenomena, however, the varying sizes of cells in different rings
can be misleading. Also, examining patterns within a ring or between rings might
not be easy simply because of their shape. When necessary, a ringmap can be
stretched into a matrix (Fig.
9
) to facilitate comparison and eliminate distortion.
Of course, a matrix can be rolled back into a ringmap.
Figure
9
depicts the annual variation in relative rates of travel of possum
(#1882) within nightly movement trajectories in a matrix view, using the same
data shown in previous figures. Evident are several patterns which reflect seasonal
