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Distribution of C 3 and C 4 grasses along an altitudinal gradient in Central Argentina
Author(s) -
Cabido Marcelo,
Ateca Norma,
Astegiano Marta,
Anton Ana
Publication year - 1997
Publication title -
journal of biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 158
eISSN - 1365-2699
pISSN - 0305-0270
DOI - 10.1046/j.1365-2699.1997.00085.x
Subject(s) - floristics , altitude (triangle) , taxon , environmental gradient , biology , ecology , mathematics , geometry , habitat
The distribution pattern of C 3 and C 4 grasses was studied in eight sites located between 350 m and 2100 m along an altitudinal gradient in Central Argentina. Of 139 taxa fifty‐nine are C 3 and eighty C 4 . Species of the C 3 tribes (Stipeae, Poeae, Meliceae, Aveneae, Bromeae and Triticeae) and C 3 Paniceae species increase in number at higher elevations; only one C 3 species was found below 650 m. C 4 Aristideae, Pappophoreae, Eragrostideae, Cynodonteae, Andropogoneae and Paniceae increase at lower altitudes. The floristic crossover point is at about 1500 m; the ground cover cross‐over point is at about 1000 m. Analysis of the relationships between % C 4 species along the gradient and nine climatic and environmental variables showed the highest correlation with July mean temperature, but all temperature variables show highly significant correlations with % C 4 . Correlation with annual rainfall is lower but also significant. These results are consistent with previous research showing the relative importance of C 4 grasses as temperature increases. C 3 species make a high contribution to relative grass coverage below the C 3 /C 4 floristic crossover point but are rare below 1000 m.