iqoq] OLSSON-SEFFER— VEGETATION ON SEA SHORES hq 



principally Fucus vesiculosus, is deposited on the beach at high-water 



mark. 



mark the limit 



toward the sea, and are characterized by a vegetation quite different 

 from that on the rest of the beach. 



Max 



-The principal influence of man on coastal 



■ind floras is a result of his endeavors to arrest the drifting of sand. 



This is mainly done by planting so-called sand-binding plants, or by 



covering the loose sand with refuse or other material. Either action 



brings about a considerable change in the natural development of the 



■rod vegetation. 



sometimes 



will 



remov 



naturally change the conditions for the original vegetation. Fires 

 are sometimes started through the carelessness of man, but as the 



formations 



seldom 



razing animals do more injury to the sand vegetation by tramp 

 th ng and u P r °oting the plants than by actual feeding on them, and in 

 6 nei g hbo Aood of many cities, where sandy beaches and dunes 

 occur, human agency is equally detrimental to the plant covering. 



Summary 



forra a mming UP th ^ physical conditions prevailing on the various sand 

 ahv ^ 10nS ° n marine coasts w e would say that the submerged beach is 



formatio ^** 1 ^ ***"' and thcrefore is the most salty of a11 the 

 and th° nS ^ ^ iS *°° Se> the temperature that of the sea water, 

 ^Peciall ^ 1S continuousl y beating. The vegetation is therefore 

 at all a } !^ apted t0 these conditions, and in most cases no plants 



re a W e to gain a footing on this formation. 



aiternati "^ ^^ ^ periodicall y washed by the waves, presenting 

 tantlv ex g teiTeStrial and aquatic conditions. It is almost con- 

 under the^f t0 the Spray and has a salty g round not very deep 



Jbmerged S K aCe * The SOil is very loose ' stiU more s0 than ° n the 

 constant^ h eaCh ' Strong insolati on, rapid evaporation, and a 

 of these ad . an§mg tem P eratu re are characteristic. It is on account 

 ^ceptionV 6156 COnditions usually devoid of vegetation, with the 



a few unicellular algae, often Cyanophyceae, but where 



