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Journal Article

Growth-survival trade-offs and allometries in rosette-forming perennials

Metcalf, C. J. E., Rees, M., Alexander, J. M., Rose, K. E.

Functional Ecology, 20:2, 217-225 (2006)

Abstract

1. Demographic rates such as growth and survival may interact directly as a result of allocation constraints, or indirectly through their relationship with structural characteristics. 2. We explored the relationship between growth and survival in a range of rosette forming species across different habitats, and investigated possible mechanistic explanations for the patterns we found. 3. Results indicated a negative association between growth and survival in small plants across species in different habitats. There was no relationship for large plants. 4. Relative growth rate (RGR) was positively correlated to specific leaf area (SLA), but unrelated to the percentage biomass allocated to roots. This argues against the hypothesized role of allocation to root mass in mediating the growth–survival trade-off. 5. The pattern of biomass partitioning was compared with the predictions of Enquist & Niklas (2002a) Global allocation rules for patterns of biomass partitioning in seed plants. Science 295, 1517–1520. In agreement with their predictions, the overall relationship between above- and below-ground biomass was isometric. However, after accounting for species-specific effects it was found that allocation to roots varied widely between species and was size-dependent, suggesting that the conventional statistical analysis (double-log regression) may be insensitive to biologically important sources of variation.

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