Environmental Studies
- Macaronesian floral region
- macrobiota
- Macrofauna
- Madagascan floral region
- maestro
- magnetic dating
- magnetostratigraphy
- maintenance evolution
- Malaysian floral region
- Malesian flora
- mallee
- Mamma
- mammillated topography
- man-induced turnover
- manganese nodule
- marginal value theorem
- mark-recapture technique
- marshy tundra
- mason bee
- mass flow