Heteroespecific differences in growth rates in height, biomass production and leaf area among co-occurring
species are ways of measuring the occurrence of interaction: facilitation or competition. Based on the broader
concept of facilitation, this type of positive interaction has been reported to explain the co-occurrence of
species in environments with high resource limitations, such as arctic and arid climates. The objective of
this study was to evaluate if facilitation could favor the initial development of
Mimosa caesalpinlifolia
and
Bauhinia cheilantha
populations, two species typical of the Caatinga region, under greenhouse conditions.
The seedlings of
Mimosa caesapinifolia Benth and
Bauhinia cheilantha (Bongard) were cultivated in pots
for 120 days in the ratios of 4: 1; 3: 2; 2: 3; 1: 4; 5: 0; 0: 5. Evaluations about structure and of some nutrient
contents (nitrogen and phosphorus) in the soil and leaf of the seedlings. The results of growth, biomass allocation
and concentrations of nitrogen and phosphorus in leaves of
Mimosa caesalpinlifolia were positively
influenced by the increase of the density of
Bauhinia cheilantha (Bongard) Steudel individuals. However,
the latter species had the lowest growth rate of intra-specific competition. If we adopt the broadest concept
of facilitation, we can affirm that there were positive interactions. As both are species of
Fabaceae that may
present associations with mycorrhizal fungi and diazotrophic bacteria, the main limiting nutrient for good
performance in the co-occurrence of these two populations should be phosphorus, since there were no differences
in the amount of nitrogen available in the soil between the beginning and the end of the experiment.
