15.2 Long-term studies
15.3 Geographical information systems
15.4 Habitat classification
Chapter 15 - Studies at large
spatial and temporal scales and the classification of habitats.
Technological advances over
the last 30 years have greatly increased the opportunities for
ecologists to study population and community processes over large
spatial and temporal distances. Two important developments have
made this possible. First, a variety of sensors on board
satellites have produced a massive amount of remote-sensed data.
This has allowed analysis of spatial and temporal variation in
both physical variables such as temperature, rainfall or the area
of open water area and biological variables such as the
distribution of closed forest, open grassland or phytoplankton
blooms. Second, the rapid reduction in the cost and size of
powerful computers has made widely available to ecologists the
computational power to analyze large data sets on widely
available personal computers. The final process aiding
large-scale studies is the gradual accumulation of long-term
data. Ecology is a recent science with origins in the 20th
century. Ecologists now have time series for a far greater number
of populations or communities than were available to earlier
generations of researchers (Leigh & Johnston, 1994). In
addition, the time length of established long-term studies is
gradually increasing to the point where time series analysis
techniques used by the physical sciences will become more
applicable. All of these developments offer new opportunities to
ecologists seeking to understand the way populations are
organized and change through time. They also offer great
advantages to conservation biologists seeking to identify, map
and protect vulnerable species or ecosystems. In this chapter, we
do not aim to give a full account of the wide range of techniques
used for the organization and analysis of large-scale spatial and
temporal data sets. Rather we aim to introduce the methods
available and direct attention to some of the numerous books and
articles which cover these topics in detail. Our purpose with
respect to spatial data is to introduce via some examples the
ways in which geographical information systems and remote sensing
data can be used by ecologists and conservationists. For temporal
data, we introduce some elementary techniques for the analysis of
the variability in population size and community structure.
| 15.1 Remote sensing
15.2 Long-term studies 15.3 Geographical information systems 15.4 Habitat classification |
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