Diversidade funcional e estratégias nutricionais de espécies arbustivo-arbóreas de cerrado e floresta estacional
Abstract
Soil fertility is one of the main determinants of the abrupt boundaries between the cerrado
and the seasonal forest. Given that the remaining patches of cerrado are surrounded by
agricultural matrices and may be impacted by eutrophication, understanding whether the
dystrophic soils of cerrado drive plant strategies and diversity might help us predict the risk
of cerrado replacement by forest vegetation and avoid loss of species and functions. In the
first chapter, we compared cerrado and seasonal forest species in terms of nitrogen and
phosphorus concentration in green and senesced leaves and resorption efficiencies. We
quantified the relationships among these traits, with other key leaf traits, and with soil
features. Nitrogen and phosphorus concentration in green and senesced leaves were more
strongly related to generalised measures of soil fertility than to soil total nitrogen and
available phosphorus, but this pattern was not so clear for resorption efficiencies. Besides,
leaf nitrogen:phosphorus ratio was lower in cerrado, despite the lack of difference in soil
nitrogen and phosphorus between both vegetation types. In the second chapter, we tested
whether cerrado and seasonal forest communities were assembled by different processes,
despite their physical proximity. We calculated the pairwise functional-phylogenetic distances
in cerrado and seasonal forest communities. We tested whether these distances were related
to soil properties in each environment. Cerrado and seasonal forest were not assembled by
different rules, and soil fertility determined the functional differences between both
vegetation types, even though it was not the only force shaping the communities. In the third
chapter, we studied patterns in chemical and structural traits in green leaves of cerrado and
forest species, in their response to soil fertility, and in their effect on litter decomposition
rates. Despite the large effect of taxonomy, soil exerted strong effect through multipleelement
control over species functional traits and strategies. The effect of such different
strategies on functioning, however, was less prominent.