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dominant vegetation” (Jones 1986:23). Daubenmire (1976) noted that this
meaning of
habitat type
corresponds to the land unit concept (Walker et al.
1986; Zonneveld 1989). In articles dealing with habitat evaluation, the term is
used in a similar sense.
The use of an ambiguous term leads to confusion in communication
between scientists. The ambiguity of
habitat
is also observed within the same
publication. Lehmkuhl and Raphael (1993), for instance, simultaneously used
“old-forest habitat” and “owl habitat.” Even ecological textbooks are not free
from ambiguity. Begon et al. (1990:853) defined habitat as “the place where a
micro-organism, plant or animal species lives,” suggesting that they consider
habitat a property of a species. However, when outlining the difference
between niche and habitat, they later described habitat in terms of a land unit
(Begon et al. 1990:78): “a woodland habitat for example may provide niches
for warblers, oak trees, spiders and myriad of other species.” Confusion arises
with respect to habitat evaluation as well. When defined as a property of a
species, unsuitable habitat does not exist because habitat is habitable by defi-
nition. In this case some land may be classified as habitat and all of this is suit-
able. When defined as a land property, all land is habitat, whether suitable or
unsuitable, for a specific species.
Why is the term
habitat
used in these various senses? The word originates
from
habitare,
to inhabit. According to Merriam-Webster (1981) the term was
originally used in old natural histories as the initial word in the Latin descrip-
tions of species of fauna and flora. The description generally included the envi-
ronment in which the species lives. This leads to the conclusion that habitat
was originally considered a species-specific property. It is interesting to note
that the definitions we traced originated both from ecology and geography,
suggesting that the confusion was not the result of separate developments in
two fields of science.
At some time habitat started to be used as a land-related concept, most
likely in conjunction with habitat mapping. A possible explanation for the
change is given by Kerr (1986), who remarked that mapping habitat
4
individ-
ually for each species would be an impossible job. He argued that a map dis-
playing habitat types and describing the occurrence of species in each type
would be more useful to the land manager. This suggests that the land-related
habitat concept arose because it was considered more convenient to map habi-
tat types rather than the habitat of individual species.
We suggest that there was a second reason for the popularity of habitat type
maps. In general the distribution of species is affected by more than one envi-
ronmental factor. Until a decade ago it was virtually impossible to display
