(S (S (S (BASENP (JJ Tropical) (NN species) (NNS populations)) (VP (VP (VBD declined) (PP (IN by) (NP (NP (QP (RB around) (NN 55)) (BASENP (NN per) (NN cent))) (PP (IN on) (BASENP (NN average)))))) (PP (PP (IN from) (BASENP (NN 1970))) (PP (TO to) (BASENP (NN 2003)))))) (COMMA ,) (SBAR (IN while) (S (BASENP (JJ temperate) (NN species) (NNS populations)) (COMMA ,) (VP (VBP have) (VP (VBN shown) (BASENP (JJ little) (JJ overall) (NN change))))))) (PERIOD .))