WordNet (r) 3.0 (2006):

bionomics
    n 1: the branch of biology concerned with the relations between
         organisms and their environment [syn: ecology,
         bionomics, environmental science]

Moby Thesaurus II by Grady Ward, 1.0:

45 Moby Thesaurus words for "bionomics":
   aerobiology, agrobiology, anatomy, astrobiology, autecology,
   bacteriology, biochemics, biochemistry, biochemy, bioecology,
   biological science, biology, biometrics, biometry, bionics,
   biophysics, botany, cell physiology, cryobiology, cybernetics,
   cytology, ecoclimate, ecodeme, ecology, ecosystem, electrobiology,
   element, embryology, enzymology, ethnobiology, exobiology,
   genetics, gnotobiotics, life science, medium, microbiology,
   molecular biology, pharmacology, physiology, radiobiology,
   synecology, taxonomy, virology, xenobiology, zoology