Distribution of C3 and C4 grasses along an altitudinal gradient in Central Argentina |
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Authors: | Marcelo Cabido Norma Ateca Marta Astegiano & Ana Anton |
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Institution: | IMBIV, UNC-CONICET, CC 495, 5000 Córdoba, Argentina,;Facultad de Ciencias Agropecuarias, UNC. CC 509, 5000 Córdoba, Argentina |
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Abstract: | The distribution pattern of C3 and C4 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 C3 and eighty C4. Species of the C3 tribes (Stipeae, Poeae, Meliceae, Aveneae, Bromeae and Triticeae) and C3 Paniceae species increase in number at higher elevations; only one C3 species was found below 650 m. C4 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 % C4 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 % C4. Correlation with annual rainfall is lower but also significant. These results are consistent with previous research showing the relative importance of C4 grasses as temperature increases. C3 species make a high contribution to relative grass coverage below the C3/C4 floristic crossover point but are rare below 1000 m. |
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Keywords: | C3 and C4 grasses altitudinal gradient climate Argentina |
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