Complex sentence: The Ranger's Service have taken steps to increase the distribution of the trees, planting both species in the park, however a great deal more could be done to make visitors and islanders aware of these unique species possessed by Arran.
Split into simpler sentences: The Ranger's Service have taken steps to increase the distribution of the trees, planting both species in the park. However, a great deal more could be done to make visitors and islanders aware of these unique species possessed by Arran.