( ( Given ( ( ( the ( ( likely low ) proportion ) ) ( of ( ferrets ( expected ( to ( die ( as ( ( a result ) ( of ( secondary ( 1080 poisoning ) ) ) ) ) ) ) ) ) ) ) ( -LRB- ( ( see above ) -RRB- ) ) ) ) ( , ( ( most ( of ( ( the reduction ) ( in ( ( the number ) ( of ( sighted predators ) ) ) ) ) ) ) ( ( ( was probably ) ( due ( to ( ( a reduction ) ( in ( rabbit abundance ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (VBN Given) (NP (NP (NP (DT the) (ADJP (JJ likely) (JJ low)) (NN proportion)) (PP (IN of) (NP (NP (NNS ferrets)) (VP (VBN expected) (S (VP (TO to) (VP (VB die) (PP (IN as) (NP (NP (DT a) (NN result)) (PP (IN of) (NP (JJ secondary) (CD 1080) (NN poisoning)))))))))))) (PRN (-LRB- -LRB-) (S (VP (VB see) (ADVP (RB above)))) (-RRB- -RRB-)))) (, ,) (NP (NP (JJS most)) (PP (IN of) (NP (NP (DT the) (NN reduction)) (PP (IN in) (NP (NP (DT the) (NN number)) (PP (IN of) (NP (JJ sighted) (NNS predators)))))))) (VP (VBD was) (ADVP (RB probably)) (ADJP (JJ due) (PP (TO to) (NP (NP (DT a) (NN reduction)) (PP (IN in) (NP (NN rabbit) (NN abundance))))))) (. .)))
Given the likely low proportion of ferrets expected to die as a result of secondary 1080 poisoning (see above), most of the reduction in the number of sighted predators was probably due to a reduction in rabbit abundance.
(ROOT (S (NP (DT A) (JJR fewer) (NNS predators)) (VP (VBZ is) (ADJP (RBS most) (JJ likely) (S (VP (TO to) (VP (VB cause) (NP (NP (DT the) (NN number)) (PP (IN of) (NP (NP (NNS rabbits)) (VP (VBG living) (PP (IN in) (NP (DT an) (NN area))) (S (VP (TO to) (VP (VB increase))))))))))))) (. .)))
A fewer predators is most likely to cause the number of rabbits living in an area to increase.