( Overharvesting ( ( is ( ( a ( serious threat ) ) ( to ( ( ( many species ) , ) ( ( especially aquatic ) ones ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Overharvesting)) (VP (VBZ is) (NP (NP (DT a) (JJ serious) (NN threat)) (PP (TO to) (NP (NP (JJ many) (NNS species)) (, ,) (NP (ADJP (RB especially) (JJ aquatic)) (NNS ones)))))) (. .)))
Overharvesting is a serious threat to many species, especially aquatic ones.
(ROOT (S (NP (NNP Overharvesting)) (VP (VBZ is) (NP (DT a) (JJ serious) (NN threat)) (ADVP (RB particularly)) (PP (TO to) (NP (JJ aquatic) (NNS species)))) (. .)))