DISPERSAL AND SURVIVAL OF PLANTS 



Doris Love 



Institut Botanique de rUniversite de Montreal, Montreal, Canada 



Speed of movement has become an integral part of human hfe. At present 

 we tend to think of distances as a matter of hours rather than miles. Man is 

 now able to swing around the globe in less than 2 hr, but he really becomes 

 aware of distances only if he has to walk on foot. Still, both man and other 

 animals have the ability of a more or less speedy transfer from one point to 

 another, an ability which can assume life-saving proportions in cases of food- 

 shortage, inclement weather, or other adversities. 



It is different with plants. Once they have taken root, it is touch and go. 

 They do not have the choice of deciding where to go next. It is purely a matter 

 of chance as to where the wind will waft the seeds, the water carry them, or 

 how far that animal, to whose feathers or pelt the seed sticks, will travel. 

 Chance alone decides even how far a seed will be conveyed between being 

 consumed and deposited. Furthermore, plant dispersal is a feature of genera- 

 tions of plants, and only a new generation can bring the species a step farther 

 on its way. 



The area with which we are concerned here is mainly covered with water. 

 It has been subjected to heavy glaciation over and over again, in parts it is 

 still in the grip of the Last Ice Age. Yet, we find on both sides of the Atlantic, 

 as well as on the islands in its northern parts, several plant species which are 

 practically undifferentiated. In some way, or at some time, these species must 

 have been able to disperse over all this area, even if it consists of landmasses 

 so far apart today that it may seem impossible for plants to bridge the 

 distances between them. 



Only a few plant species are actually adapted for long-distance dispersal, 

 having seeds or other reproductive parts which can be carried far away from 

 the immobile mother plant. Many more species are adapted to dispersal over 

 relatively short ranges, from a few meters up to several kilometers, but in our 

 particular area the shortest span between two landmasses is the 1 1 km gap 

 between the islands in the Spitsbergen chain. The other distances are con- 

 siderably longer, most of them over 300 km and all the way up to the 1761 km 

 between Jan Mayen and Iceland (cf. Table 1). 



Some plants have reproductive parts which seem truly adapted for transport 

 over long distances by wind or water, or by sticking to feathers or pelts. 



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