FIELD WORK ON ECOLOGY 37 
IV. Influence of Animals. 
(a) Effect of absence of insects owing to severe feat This 
will probably be seen in a lessened number of fruits and, 
ultimately, of plants. 
(b) Effect of abundance of insects on pollination, ete. 
(c) Effect of birds on dispersion of fruits and seeds. 
(d) Result of introducing certain animals into pastures. _ 
V. Observations on Seashore Vegetation. 
(a) The plants found in shifting sand—that is, sand blown 
about by the wind, so that the plants are we) covered up, 
and have to push their way up again. | 
(i.) The grasses binding the shifting sand together should 
be noted. 
(ii) An exact list should be made of the herbs found in 
the shifting sand at the level of the sea, where the sand 1s 
wet at every tide, and also above the level of the sea water, 
as, for instance, the shifting sand in the clefts of rocks. 
(6) The plants found in the firmer sand, which is being 
built up by the grasses into sand-dunes. The herbs found 
here are far more numerous. Their general characteristics 
should be noted, and compared with the same ae found 
inland. 
