Scilly’s Changing Habitats

As the sea level rose around Ennor, so the land was reducing in size.

With over 150 bronze age burial mounds in the islands, (dating from 2000BC), it seems there were quite a few people in residence, in what was a gradually reducing land area.

The natural vegetation for an unpopulated Scilly Isles, would be deciduous forest.  Samples of peat show that there was woodland – mainly oak, with some elm and ash.

However, by the time of the late iron age village of Halangy Down, (which was believed to be occupied into the 2nd century AD), the forest had been almost completely cleared, to make way for farming, as the population grew and the land size reduced.

There are few trees on the islands today, most being planted as windbreaks.

The loss of the woodland habitat led to the loss of the animals that would have lived in that habitat.  Many animals, that are common just 28 miles away in Cornwall, are not found on the Scilly Isles.

However, it hasn’t all been loss.  Some species have arrived on the islands.  Shipwrecks have caused this to happen by accident, but some introductions have been deliberate, such as the planting of Tresco’s sub-tropical gardens.  Seeds from there have dispersed across the islands, with the help of the wind and birds.

Introducing a new species often upsets the previous balance of nature.  Hedgehogs were brought in as pets and have since escaped and multiplied.  They are fairly safe on the islands, without foxes etc to hunt them down, and are disrupting the food chain by consuming too many slugs and snails.  They also eat bird’s eggs and nestlings.

But for the birds there is also a success story.  I’ll tell you about that next week.