Conservation Science in the RSPB 2006

22
Mapping moorland habitats for birds
using satellite images
The abundance of golden plovers was
poorly predicted by satellite imagery.
Chris Gomersall (rspb-images.com)
Uplands and blanket bogs in the
UK are of national and
international conservation
significance, but some key bird
populations there have recently
declined. Understanding the
reasons for this depends on good
information on both birds and
their habitats, but the extent of
these areas means this may be
difficult to obtain using
conventional methods.
Comparison of the amount of heather in a subset of 26 2-km 2
survey plots in south-east Scotland estimated from a supervised
classification of a Landsat7 image (predicted) and derived from
field-collected data (observed). Two data points overlap.
Prediced % heather
80
60
40
20
The RSPB and the Scottish
Agricultural College explored the
potential of satellite imagery to map
moorland vegetation over extensive
areas. Satellites measure differences
in light reflected by different land
cover. Using a subset of habitat data
collected in a previous study,
differences in reflectance between
different plants were used to
produce predicted vegetation maps
for south-east Scotland,
distinguishing the main plant species
or taxa. These predictions were
tested against the remaining data in
the reference set.
Although the reference data had not
been collected specifically for use
with remote sensing, common
species (eg heather, purple moor
grass) were mapped accurately.
Relatively scarce plants (eg tall
rushes, moss) were not so well
mapped and predictions of variation
in vegetation height were
relatively weak.
0
0 20 40 60 80
Observed % heather
Using bird:habitat association
models developed in the earlier
study for red grouse and golden