to a cost a very useful tool for vegetation mapping. Examples can be found ecological interpretation of this information must be translatable
in a variety of landscapes in literally every country in the world. to the concrete areas for which a particular management practice
is imposed. In figure 4 this translation level is indicated by the
stal areas One of the main problems in the practical application of remote word "synthesis". The central unit within the synthesis is the
ed, at one sensing for vegetation mapping is that not all relevant landscape ecotope or physiotope. An ecotope is defined as the smallest,
itemporal ecological processes are active at the same level of detail in the ecologically homogeneous unit in a landscape (Zonneveld, 1979;
el region. landscape. The effect of desiccation and decalcification on the Naveh and Lieberman, 1984; Haines-Young et al, 1993). A
of ERS vegetation of a dune slack must be monitored at a larger scale physiotope is the abiotic part of an ecotope or ecosystem and is
n Dundee than the invasion of Sea Couch (Elymus pycnanthus) on salt ^ homogeneous for a number of abiotic factors (Stordelder and
to study marshes or changes in the total area covered by saltmarsh Hommel, 1990). Both a concrete management unit and a unit on a
y changes vegetation in the Waddensea. If the scale of a vegetation map is vegetation map can be considered as landscape units consisting of
data. not geared to the detail level of the information requirements, a one or more ecotopes or physiotopes. Hence the management
manager may end up with a too detailed or too general map. units and mapping units are interchangeable on this level. The
essence of the ecological interpretation is to provide a framework
of (theoretical) vegetation types, indicative for stages in the
4.2 À conceptual basis for mapping and monitoring of coastal progress of landscape ecological processes (eg. desalinisation,
ecosystems. land subsidence, eutrophication). By assessing the similarity
between the actual vegetation and the theoretical vegetation types,
inagers of At the Survey Department a method has been developed to ^ the former can be translated into a progression stage of a
jn of the translate landscape ecological processes into vegetation landscape ecological process.
icture are development series, map these series at various scales with
the result different remote sensing techniques and provide managers and By presenting vegetation development series at the
tors (viz. policy makers means to decide if a specific problem can be ecotope/physiotope level, the ecological interpretation can be
and soil tackled by remote sensing and if so, which will be the appropriate translated directly to the management component. The last step is
) active at scale and survey frequency (Kloosterman et al, 1995; Janssen et to asses at which scale the vegetation types, indicative for
proach to al, 1996). This method comprises three main components (see particular landscape ecological process, can be monitored
ze due to figure 4): sufficiently homogeneous and which remote sensing technique is
on reacts l|. Nature management: What are the management problems and most appropriate (see table 1).
10nitoring aims?
re and, in 2. Vegetation mapping: What can be depicted with remote It is believed that the conceptual framework developed at the
speed of sensing? Survey Department is not area specific and is broadly applicable
| manager 3. The ecological interpretation: What is the ecological meaning for mapping and monitoring of coastal ecosystems. The required
> develop- of the observed vegetation changes in relation to the scale depends on area specific conditions (eg. diversity and area
area and management problems and aims? covered by per vegetation type) and level of detail of the required
. Remote management information. The smaller the scale, the more
yven to be These components must be tuned in such a way that the appropriate satellite remote sensing becomes. Digital images are
——s information on a map, the information presented by the ecological more suitable for quantitative monitoring than changes assessed
interpretation and the information requirements set by nature by visual interpretation of analogue aerial photographs. In general
managers or policy makers are interchangeable at a certain level. however, digital spectral information alone is not a sufficient
In other words since management as well as mapping ultimately basis for a meaningful classification of coastal ecosystems.
deal with concrete areas, the information on a map as well as Analogue (aerial photographs) remain an important tool for a
aerial aerial aerial CAESAR SPOT
indicative vegetation actual vegetation photograph photograph | photograp 0.75x0.75m 10x10m
type type 1:2.000 1:5.000 h 1:18.000
multi spectral multi spectral
false colour false colour | B/W PAN airborne spaceborne
scanner scanner
Sueda maritima Sueda maritima d + _
community type
Atriplex litoralis Atriplex prostrata + +/- - Je s
community type
Puccinellia maritima Puccinellia T + +/- +/- -
community maritima type
Artemisia maritima Artemisia + + +/- + +/-
community maritima type
rem Table 1: "Mappability" of indicative vegetation types
47
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B6. Vienna 1996