( ( ( The introduction ) ( of ( ( rabbits and ) rats ) ) ) ( ( ( may also ) ( have ( ( increased ( ( the number ) ( of ( feral cats ) ) ) ) ( in ( ( ( the habitat ) , ) ( which ( are ( ( another ( major predator ) ) ( of numbats ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN introduction)) (PP (IN of) (NP (NNS rabbits) (CC and) (NNS rats)))) (VP (MD may) (ADVP (RB also)) (VP (VB have) (VP (VBN increased) (NP (NP (DT the) (NN number)) (PP (IN of) (NP (JJ feral) (NNS cats)))) (PP (IN in) (NP (NP (DT the) (NN habitat)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBP are) (NP (NP (DT another) (JJ major) (NN predator)) (PP (IN of) (NP (NNS numbats)))))))))))) (. .)))
The introduction of rabbits and rats may also have increased the number of feral cats in the habitat, which are another major predator of numbats.
(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.