Linking post-fire regenerative strategy and leaf nutrient content in Mediterranean woody plants

Saura-Mas S., Lloret F. (2009) Linking post-fire regenerative strategy and leaf nutrient content in Mediterranean woody plants. Perspectives in Plant Ecology, Evolution and Systematics. 11: 219-229.
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Doi: 10.1016/j.ppees.2009.04.002

Resum:

We explored differences in leaf nutrient contents between species from Mediterranean shrublands with the ability to resprout after disturbances such as fire (resprouters) and others without this capacity (non-resprouters). Since it is to be expected that resprouting capacity is related to a more conservative use of nutrients, we hypothesize that resprouter and non-resprouter species will differ in their leaf nutrient concentrations. We measured the following leaf traits: leaf carbon content (LCC), leaf nitrogen content, leaf phosphorous content (LPC), leaf potassium content, leaf calcium content (LCaC), leaf magnesium content and leaf sodium content, in 30 woody species coexisting in a coastal shrubland. We also considered the influence of species' taxonomic affiliation in our analysis. Non-resprouters had higher LPC and LCaC than resprouter species, and lower LCC, which could be related to their cell and life-history properties. This study also suggests that non-resprouter species have more P in their leaves and are less limited by P than resprouter species. Overall, the differences in leaf nutrient contents suggest that shifts in the proportion of resprouter and non-resprouter species resulting from changes in the fire regime may have effects on the functional properties of the ecosystem. © 2009 Rübel Foundation, ETH Zürich.

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Relationship between post-fire regeneration and leaf economics spectrum in Mediterranean woody species

Saura-Mas S., Shipley B., Lloret F. (2009) Relationship between post-fire regeneration and leaf economics spectrum in Mediterranean woody species. Functional Ecology. 23: 103-110.
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Doi: 10.1111/j.1365-2435.2008.01474.x

Resum:

1. Recent work has identified global-scale relationships between key leaf traits (leaf economics spectrum). However, it is important to determine whether this approach can be applied at local scale with smaller subsets of species facing similar environments. Since fire is a key process in Mediterranean shrubland dynamics we analyze whether fire-related life-history traits influence the pattern of correlation between the leaf economic spectrum and leaf moisture traits. 2. Using structural equation modelling and exploratory path analysis, we developed alternative models to test how interspecific leaf traits are related to the seasonal variation of water content (leaves and shoots) and to the type of post-fire regeneration of Mediterranean woody species. 3. This study demonstrates that for these species seasonal variation in water content and fuel moisture would be better predicted by the presence or absence of a trait describing post-fire seedling establishment than by the leaf economic spectrum traits. However, leaf dry matter content (LDMC) is influenced by both the leaf economic spectrum and the post-fire regenerative type. 4. Seeder species (those that recruit via seeds immediately after fire) present lower LDMC and higher relative seasonal variation of relative water content (RWCrsv) than non-seeders. We hypothesize that since seeder species mostly evolved under the Mediterranean climate, they developed a particular strategy of drought tolerance (without causing an effect to the relation between the volume occupied by cytoplasm relative to the volume occupied by cell walls), which is the cause of the observed relation between LDMC and RWCrsv. 5. This study suggests that the leaves of Mediterranean woody species would follow the general leaf economics spectrum (Wright et al. 2004) but that specific selective forces, such as disturbance regime, acting at regional scale also play a relevant role to explain leaf traits related to water content. © 2008 The Authors.

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