Predicting forage quality from Functional Diversity in a subtropical seasonally dry forest of Argentina.

ENRICO, L; CONTI, G; LIPOMA, ML; FACCIANO, ML; DÍAZ, S

Simposio; 59th Annual symposium of the International Association of Vegetation Science; 2016

Natural fodder and the secondary productivity derived from it are among the ecosystemprovisioning services most valued by the inhabitants of the semi-arid Chaco region ofArgentina. Under different land use regimes, plant communities and their associatedecosystem processes can vary considerably. These changes may be determined either bychanges in the identity of the dominant species, or by changes in their relative abundances.Under the mass ratio theory (Grime, 1998) it is expected that those communities dominatedby plant species of a higher quality for herbivores, as reflected by plant attributes positivelyrelated to consumption rates, would result in higher-quality fodder. Considering this, weaimed to analyze changes in the community weighted means for a number of traits related tospecies potential for trophic transfer to herbivores. We sampled vascular plant communitiescorresponding to three different land use types: Secondary Forest, Closed Shrubland andOpen Shrubland). We measured the relative abundances of the ten dominant species, andanalyzed five leaf traits: Specific Leaf Area (SLA), Leaf Dry Matter Content (LDMC), LeafToughness (LT), Leaf Nitrogen (LNC) and Phosphorus Content (LPC). Based on the relativeabundances and attributes of the dominant plant species, we obtained the CommunityWeighted Mean (CWM) for each trait, under each land use type. Open shrublands showed asignificantly lower leaf phosphorus content CWM than secondary forests and closedshrublands, higher LDMC CWM than Secondary Forests, and a lower value of SLA CWMthan Closed Shrublands. We found no significant difference in leaf toughness or leaf nitrogencontent CWMs. Therefore open shrublands are inferior than secondary forests or closedshrublands in terms of forage quality.