( ( With ( ( the decline ) ( of ( ( such ( natural predators ) ) ( as ( ( wolves and ) tigers ) ) ) ) ) ) ( , ( ( ( the number ) ( of ( wild boars ) ) ) ( ( has ( ( increased , ) ( ( causing problems ) ( for ( farmers ( in ( some areas ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN With) (NP (NP (DT the) (NN decline)) (PP (IN of) (NP (NP (JJ such) (JJ natural) (NNS predators)) (PP (IN as) (NP (NNS wolves) (CC and) (NNS tigers))))))) (, ,) (NP (NP (DT the) (NN number)) (PP (IN of) (NP (JJ wild) (NNS boars)))) (VP (VBZ has) (VP (VBN increased) (, ,) (S (VP (VBG causing) (NP (NNS problems)) (PP (IN for) (NP (NP (NNS farmers)) (PP (IN in) (NP (DT some) (NNS areas))))))))) (. .)))
With the decline of such natural predators as wolves and tigers, the number of wild boars has increased, causing problems for farmers in some areas.
(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.