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citrus groves of California are maintained for growing citrus or are sold 
for housing developments. But even if the best citrus lands are con- 
verted to growing houses and people, there are yet outer lands which 
can be used for growing citrus. The same sort of argument does not 
hold for our coastal areas (nor, for that matter, for any of our wetlands). 
The coastal wetlands are our most productive natural systems and a 
considerable amount of this production is, and much more could be, 
used by our citizens. Most of our fish and shellfish production depends 
on these areas. A considerable part of our recreational activities are 
concentrated at the edge of the sea. A number of industries cannot be 
located anywhere but directly on the coast, the most obvious examples 
being ocean shipping and fishing. 
The limited nature of the coast which is essentially a linear rather 
than an areal feature of the landscape, and the greatly increased pres- 
sures which our growing population and economy are putting on the 
coast make it imperative that we plan to preserve these areas. 
The student papers that accompany this note detail in brief form 
some of the problems associated with the coastal areas. Perhaps they 
overemphasize our lack of knowledge, for several seem to indicate that 
we would have to do years of work before making reasonable recom- 
mendations about coastal land use. I believe the intention was merely 
to emphasize the difficulty of the problem which became apparent to 
the students as they tried to find definite answers to the problems 
and questions they encountered. 
A number of general conclusions can be summarized from these 
reports: 
The coastal ecosystems of the United States are adapted to the 
changing conditions that are found in the coastal lands and waters 
throughout the year. Many of the kinds of animals important to us 
depend upon these seasonal changes to coordinate their lives. People 
may like to live in constant climates—air conditioned when hot, heated 
when cold—but many animals do not. Changes which we make in 
coastal climates which tend to even out the extremes, or to make 
changes more abrupt will be generally detrimental to the organisms 
living there. 
Not only are changes in climate important, but interactions in 
various aspects of climate are important. For example, the interactions 
of temperature and salinity determine the survival of the young of 
many estuarine species of commercial importance. 
Actions taken in one relatively small area of the coast may have 
consequences over a much larger region. The circulation of water 
along the coast and the migrations of animals up and down the coast 
distribute the effects of human action over a wide area. 
Actions taken anywhere and everywhere in the watershed of a river 
will have their effects concentrated into the estuary into which the 
river empties. Thus land use many miles from the coast may be 
critical to the health of the coastal region. 
An accidental event, such as the introduction of a new species of 
aleae, may have important effects on the ecology and even the geology 
of the coastal region. I think the point to be made is that land use 
policy must be sufficiently flexible to adapt to such accidental, unpre-— 
dictable changes as will certainly occur. 
