The environment around us is a complex ecosystem each piece being reliant on most of the others.It can only be truly understood if each piece is carefully examined and its relation to the others recognised. The benefits of plants to animals is easy to see providing either food shelter and camouflage or medicine. Less obvious and mostly over looked are the needs that plants have for animals. Without Animals most species would have a difficult time spreading.Pollination could not occur or seed spread by consumption as with birds but a there is another problem: Germination. Seeds need sunlight warmth and moisture to germinate. If you take a handful of seed and drop it on a grassy piece of roadside verge (this is similar to the kind of thing you would find naturally) almost none of it will grow.The seed is overshadowed and cannot get to soil or sufficient moisture to grow. This is where the animals come in.Horses are heavy hard hoofed animals using a lot of force to move themselves around. Watch a race to see what I mean.The hoof cuts into grass leaving large numbers of open holes in the turf.This gives seed a good chance to become established. Fields used solely for grazing horses usually have quite a diverse range of plants growing in them. Two fields I know of that are used like this have rare species growing in them almost certainly because of the horses there.One has a huge colony of Seaside Centaury and the other is littered with Early Purple and Common Spotted Orchids as well as dozens of other interesting plants. Cows have a similar effect on their surroundings but intensive grazing keeps the species count down.They are also not as sure footed as horses and tend to slip and slide a lot destroying even some perrenial plants. Pigs are almost always over grazed if they are kept on grassland. Their natural environment is woodland where they turn over soil and leaf litter looking for worms and funghi.Here they perform a vital role opening up the ground for seed to grow. Sheepare a disaster as far as wildflowers and trees are concerned.They do not disturb the soil much at all ,because they are light and soft footed being cloven hoofed. Sheep eat almost all species of plants.they also nibble the grass and herbage very short cutting off seedlings and leaving quite a bleak environment with only the hardiest species surviving.However Sheep come from mountainous regions and in their true environment are quite scarce so this kind of grazing actually opens up the grass allowing sunlight to reach the ground.mountains that are not subjected to todays farming techniques are extremely varied and rich in species. Goats are similar to sheep but they browse scrubland almost never touching grass at all and so have little effect on seeds. They can however have a devastating effect on seedlings and will destroy huge numbers of tree seedlings and saplings.Goats have a valuable role in clearing heavy underbrush allowing light into the woodland floor and allowinglight down under scrubland encouraging new woodland growth.