Intra- and inter-specific competition between seedlings of Acacia etbaica and a perennial grass ( Hyparrenia hirta)
Intra- and inter-specific competition between seedlings of Acacia etbaica Schweinf. and the grass Hyparrenia hirta (L.) Stapf. was studied to evaluate the influence of the perennial grass on the establishment of the tree seedlings. The experiment was conducted using a replacement series in which pla...
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Veröffentlicht in: | Journal of arid environments 2003-11, Vol.55 (3), p.441-451 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Intra- and inter-specific competition between seedlings of
Acacia etbaica Schweinf. and the grass
Hyparrenia hirta (L.) Stapf. was studied to evaluate the influence of the perennial grass on the establishment of the tree seedlings. The experiment was conducted using a replacement series in which plants were grown in a greenhouse at an overall density of six individuals per pot, providing combinations of the two species from 0:6 and 6:0. Indices of intra- and inter-specific competition, relative crowding coefficients and relative yield totals (RYTs) were calculated from the dry weight data. For both shoots and roots, the crowding coefficient of
Hyparrenia towards
Acacia was five- to ten-fold that of
Acacia towards
Hyparrenia, which indicated a high competitive strength for the grass species. RYT values of the two species averaged 1.25, indicating some degree of resource complimentarity. Both species had comparable intra-specific competition based on shoot yield. However, based on the root yield, intra-specific competition of
Hyparrenia was slightly lower than that of
Acacia. Inter-specific competition of
Hyparrenia on the root yield of
Acacia was more than five times greater than vice versa. With more crowding, shoot/root ratio decreased more in
Hyparrenia than in
Acacia for pure stands as well as for mixtures which indicated that
Hyparrenia could adjust biomass allocation. In general, the results indicated that
Hyparrenia was competitively aggressive towards
Acacia and may inhibit the growth of tree seedlings when the latter are planted within the grass community. Implications of the findings in terms of land reclamation efforts are discussed. |
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ISSN: | 0140-1963 1095-922X |
DOI: | 10.1016/S0140-1963(03)00052-1 |