Ecological aspects of Hymenochaetaceae in an area of Caatinga (semi-arid) in Northeast Brazil

The diversity of Hymenochaetaceae and its relationship with native plants of the Caatinga were investigated in two stands (56 km(2) each) in the Parque Nacional do Catimbau, State of Pernambuco, Northeast Brazil. The basidiomata collected on both live and dead trees represented 14 species of Hymenochaetaceae. Eleven of them belonged to Phellinus, six of which were new records to the Brazilian semi-arid area (P. grenadensis, P. linteus, P. maxonii, P. melleoporus, P. rimosus, and P. rhytyphloeus). Hymenochaetaceae diversity was not influenced by differences between stands, caused mostly by agriculture (subsistence farming), logging and tourism. The occurrence of taxa of Hymenochaetaceae was not significantly related to humidity, although P. piptadeniae and P. rimosus were more frequently sampled during the dry season. Even if most of the specimens of Hymenochaetaceae, Phellinus and P. piptadeniae have been found on live hosts, this observation was not statistically supported. On the other hand, P. rimosus occurred only on live hosts. The occurrence on live hosts may indicate a parasitic relationship, but they may be colonizing dead tissues of the live plants. Plants of Piptadenia and P. moniliformis had high incidence of Hymenochaetaceae, Phellinus and P. piptadeniae, while Caesalpinia microphylla had high incidence of Hymenochaetaceae, Phellinus and P. rimosus, suggesting that P. piptadeniae is host-recurrent and P. rimosus is host-specific on species of Fabaceae in the studied area. The results indicate that, at least when analysing Hymenochaetaceae, the biome Caatinga differs from other tropical forests where higher species richness is observed on decaying rather than live substrata, and where host-specificity/recurrence have been shown to be low.