The Heyday of the Environmental Movement, 1960–1979 131
Finally, the marshes are productive because
there is almost no time during the year, even in
the north, when there is not some plant growth
taking place. In the south, it is warm enough for
the Spartrina to grow all year. At the latitudes of
the mangroves, all plants grow all of the time if
they are well watered. But in the north, where the
land plants and Spartrina cease activity during
the winter, the algae in the marshes continue to
grow throughout the year. The relatively constant
growth of the mud algae in southern marshes and
the midwinter blooming of the algae in the waters
of the northern marshes are examples of year-
round photosynthetic activity which helps move
the marshes ahead of their neighboring terrestrial
or marine areas in production.Source: John and Mildred Teal, Life and Death of a Salt
Marsh (New York: Ballantine Books, 1971), pp. 193-95.Clams, oysters, and mussels help form the
sediment and nutrient trap because of their
method of feeding. They remove all of the par-
ticles from a large volume of water as it passes
over their gills and deposit most of them in neat
pseudofeces bundles.
Nutrient concentrations in soils are thou-
sands of times greater than those in waters. As a
result, plants growing in soils are more produc-
tive than those floating in the water. A relatively
small amount of soil can bring a large amount
of plant nutrients into the marsh. It may even
be deposited on just a few days of the year when
the river carries an extra heavy burden of sedi-
ment resulting from an occasional flooding rain
far from the marsh.
* * *DOCUMENT 110: Ian McHarg on the Fitness of Ecosystems (1969)
Ian McHarg, the father of the environmental impact statement, which requires developers to justify the effects
of their actions on the natural world, was ever conscious that natural landscapes had evolved over time because
they were the most suitable for their ecosystems. McHarg was a Scottish landscape architect whose writing
focused on land use planning.If evolutionary success is revealed by the
existence of things and creatures, then their cre-
ative adaptations will be visible, not only in the
organs and the organisms, but in ecosystems as
well. If this is so, then the natural communities
of plants and animals which the first colonists
encountered in aboriginal America were the
best expression of environmental adaptation,
exploited by available organisms. Where these
persist, this will hold true today. Thus not only
is there an appropriate community of creatures
for any environment, and successional stages
towards this climax, but the community is in
fact, expressive of its appropriateness, its fitness.
This is a conclusion of enormous magni-
tude to those who are concerned with the land
and its aspect: that there is a natural associationwhich is most appropriate—indeed, in the absence
of man, one which would be inevitable for every
place upon the earth—and that that community
of creatures is expressive of its fitness. This I
would call the identity of the given form.
If this is so, then we can accept that within
any generalized area there will be ideal exam-
ples, both of fitness and the expression of fit-
ness. In these locations, presumably, there are
some special successes that are visible and com-
prehensible. The ecosystem, the organisms and
their organs are not only fit, but are most fitting.
This is an important conception because it has
a relevance to the man who wishes to design for
nature. The man who seeks to create metaphysi-
cal symbols is really concerned with idealizing.
* * *