Respostas ecológicas de plantas de campos rupestres ferruginosos ao aumento experimental de nutrientes

Abstract

Plants of ferruginous rupestrian grasslands have the capacity to tolerate and survive in soil with nutritional poverty and heavy metals. This study tested the following hypotheses: (i) the seedling survival differs between substrates with different nutritional conditions; (ii) the species have better performance in substrates with nutritional enrichment compared to the substrate control. We conducted an experiment in which we cultivated for 150 days seedlings of nine species of four plant families in six substrates: control, three with different levels of NPK (4: 14: 8), with organic fertilizer and another with a commercial substrate for nursery garden. The percentage of survival did not differ among substrates, but varied among species (between 40 and 100% survival). Eight seedlings out of evaluated nine species showed higher growth and accumulation of biomass in the assessed responses when grown in organic or commercial treatment (up to 10 times greater). The proportion root-branch, with few exceptions, was higher in the control and substrates with three NPK levels. These species already have functional adaptations to survive in this type of environment with strong environmental filters. This shows high phenotypic variability, as even being able to survive in poor soil of ferruginous rupestrian grasslands, these plants can adapt capturing the available resources in the most fertile soils. Specific responses may explain the coexistence of species communities that supports niches division along a gradient of resources and different adaptive strategies.