The physical environment - Fundamentals of the Physical Environment - page 9

of the satellite image, ( Plate 12.13 )). On the satellite image
the outcropping strata of the horizontally bedded rocks
appear as terraces, especially on sunlit slopes, and drumlins
deposited by Devensian ice are also visible in the upper
parts of Wharfedale.

dynamic process-based subject in recent decades (Chorley
and Kennedy 1971; Phillips and Renwick 1992).
In addition to a concern for measurement, quantifica-
tion and modelling, the systems approach is important in
two ways. First, it emphasizes interactions among all
elements in the landscape. The assumption is that a
process or feature can be understood only as it interacts
or adjusts to other processes or features in the physical
environment. Second, a systems approach is concerned
with whole systems rather than one or two component
parts. This is the holistic approach, in contrast to the
reductionist approach, which concentrates on one or two
components only. The holistic study of complex systems
became a major feature of science in general in the last
three decades of the twentieth century.
In order to determine quantitatively the rates at which
processes in are operating in the physical geography of
Upper Wharfedale, measurements need to be collected by
mapwork, fieldwork, field experimentation and moni-
toring, and the laboratory analysis of sediment, soil and
water samples. Statistical analysis of the data, and several
approaches to computer modelling, would then be needed.
Before starting the study a hypothesis would be construc-
ted, and the testing of this hypothesis would be a major
focus of the investigation. For example, the free faces or
'scars' on valley sides in Upper Wharfedale often have small
screes or talus slopes at their base ( Plate 1.5 ). One asks the
question: how are the features of the free faces related to
the screes? They occur together in the landscape but do the
properties on one control the properties of the other?
These and similar questions are best answered if the
free faces and screes are regarded as a structured system.
A working null hypothes is would be: 'the free faces and
screes are totally unrelated'. Work in the field, the physical
laboratory and the computer laboratory would test the
validity of this working null hypothesis. Figure 1.4 shows
the morphological characteristics that could be measured
in fieldwork. The relationships shown by the lines
linking the properties indicate where the correlations are
statistically significant, together with an indication of
whether the correlation is positive or negative (+ or -).
For example, the height of the free face is positively
correlated with scree height (i.e. the bigger the free face,
the bigger the scree), whereas the long axis (size) of debris
is negatively correlated with the mobility of the scree
(i.e. the smaller the debris, the more mobile is the
scree). The free-face/scree system is a morphological
system , being still essentially descriptive, but it advances
understanding by showing the network of structural
relationships operating between the free face, the scree and
the size of the scree material.

UPPER WHARFEDALE AS AN
ENVIRONMENTAL SYSTEM

The physical geographer does not merely describe the
various components of the landscape being studied.
Greater knowledge and understanding are achieved by
defining the relationships between the components (i.e.
their interconnections or interactions ). How have the soils
of Upper Wharfedale been influenced by the underlying
rock strata? How are the bedforms in the river Wharfe
affected by the gradient of the river channel? These and
numerous other research questions demand that the
investigator adopts an analytical approach to build on the
descriptive approach of the preceding section.
In the past thirty years the methodology of systems
analysis has developed to investigate complexity in the real
world. In geography it has been adopted by studies of
natural systems (e.g. geomorphological systems and
ecosystems) as well as of human systems (e.g. urban
systems and farming systems). A system is defined as:
'a set of interconnected parts which function together as
a complex whole'. Energy and matter move through
systems by a series of flows, cycles and transformations.
Components of the system (e.g. landforms, ecosystems,
soil profiles)are conceptualized as stores in the system.
Usually the whole environmental system of the drainage
basin is subdivided into interconnected subsystems , i.e.
individual units of which a system is composed. Thus in
the drainage basin it is possible to recognize the climate
subsystem, the land-surface sediment and topography
subsystems, the vegetation subsystem, the soil subsystem,
the aeration zone subsystem, the groundwater subsystem
and the channel subsystem.
Why did a systems viewpoint become the norm in
physical geography during the period 1970 to 2000?
Traditional approaches seemed to be leading nowhere,
except to larger and larger lists of descriptive facts, with
few ideas on what processes were at work. The emphasis
of research moved more and more to investigating the
dynamic behaviour of systems (geomorphic systems,
hydrological systems, soil systems, ecosystems, atmos-
pheric systems) as opposed to the description and
classification of landforms, water, soils, vegetation and
climates. In short, physical geography has become a