Environmental Engineering Reference
In-Depth Information
(a)
(b)
(c)
(d)
FIGURE 10.1
Examples of spatial heterogeneity relevant to ecosystem science. Although these
figures represent medium to coarse scales, spatial heterogeneity can exist on any scale, from intervals of milli-
meters to continental scope. (a) A treefall gap contrasting with the closed canopy of an old growth hemlock-oak
forest on the grounds of Montgomery Place on the banks of the Hudson River. (b) A model of the surface eleva-
tion of the Dead Run watershed in metropolitan Baltimore, MD, based on LiDAR imagery. Both natural and mod-
ified surface features, such as roadbeds, leveled areas for large buildings and parking lots, culverts, and
channelized drainages, are shown. Blue represents low elevations, and red represents higher elevations. (c) A
mountainous landscape in Bhutan, showing cultivated and grazed fields, farmhouses, fallow field shrubland, and
patches of intact and lightly managed forest ranging from lower-elevation pine, through oak, to coniferous domi-
nance higher on the slopes of the Himalayan front range. (d) A vacant lot in an old rowhouse neighborhood in
Baltimore, MD, that has been converted to a tidy lawn and flower garden by neighboring residents.
(Photos (a),
(c), and (d) copyright S.T.A. Pickett. Photo (b) copyright Dr. Andrew Miller, University of Maryland, Baltimore County.
All used by permission.)
a system or differences expressed in arrangement of those elements. Of course, both
aspects can play a role in a specific case of heterogeneity, because attention to kinds of ele-
ments and to arrangement of elements suggests a continuum of complexity in hetero-
geneity (Cadenasso et al. 2006).
Another stimulus for thinking about systems as spatially heterogeneous has affected
ecosystem science. Since the mid-1970s, landscape ecology has emerged as a discipline
