Complex sentence: The Buckfast hybrid bee was developed by "Brother Adam", born Karl Kehrle in 1898 in Germany, who was in charge of the Abbey's beekeeping, but the bees were being decimated by "Isle of Wight" disease.
Split into simpler sentences: The Buckfast hybrid bee was a bee developed by "Brother Adam", born Karl Kehrle in 1898 in Germany, who was in charge of the Abbey's beekeeping. Bee populations were being decimated by "Isle of Wight" disease.