Complex sentence: Concerns had been raised in the early 1970s about the effect of phosphate mining on the flora and fauna of Christmas Island, with a particular focus on the habitat of Abbott's Booby ("Papasula abbotti"), which appeared in danger of extinction.
Split into simpler sentences: Concerns had been expressed in the early 1970s about the effect of phosphate mining on the flora and fauna of Christmas Island. A particular focus was on the habitat of Abbott's Booby ("Papasula abbotti"), which appeared in danger of extinction.