The caloric contents of 42 species and their composition in a Leymus chinensis steppe community of Inner Mongolia in China were determined and analyzed for 11 years. The caloric content (x±1SD) of aboveground parts for plant species varied from (13156±1141) J/g ash-contained to (18141±527) J/g. The average caloric content of all species was (16899±840) J/g and their inter-specific CV was 4.9%. Of all the species, Caragana microphylla had the highest caloric content (18142 J/g). Grasses had a higher (P < 0.05) average caloric content (17425±291）J/g than forbs (16734±844) J/g. When the herbaceous species were classified into subgroups according to life form and growth form, the order of average caloric contents, from high to low, were: tall grasses (17717±92) J/g>Legume (17228±433) J/g>short grasses (17250±218) J/g>remaining forbs (16784±529) J/g>subshrubs (16719±69) J/g>annuals and biennials (15911±1759) J/g.
There was a positive correlation (P < 0.05) between the caloric contents of 42 species and their relative biomass in the community. When all species were classified into three groups according to their composition in the community, the averaged caloric contents, weighted by the species relative biomass, followed the order: Dominant (17740 J/g)>companion (17244 J/g)>incidental (16653 J/g). The plants with high caloric contents were more competitive, which allows them to gain a dominant status, while the competitive abilities of plants with low caloric contents were generally weak. The latter made up the companion or incidental species in a steppe community.