Functional diversity of tree cavities for secondary cavity-nesting birds in logged subtropical Piedmont forests of the Andes

SCHAAF, ALEJANDRO A.; GOMEZ, DANIELA; RUGGERA, ROMÁN A.; TALLEI, EVER; VIVANCO, CONSTANZA G.; POLITI, NATALIA; RIVERA, LUIS

FOREST ECOLOGY AND MANAGEMENT

ELSEVIER SCIENCE BV

Año: 2020 vol. 464

0378-1127

Studies about functional ecology have increased in the last years and they are currently an important element forthe understanding of ecosystem processes. The aim of this study was to compare different functional traits ofcavity trees for secondary cavity-nesting birds, between unlogged (control forest) and conventionally loggedsites in subtropical piedmont forests of NW Argentina. Between 10 and 20 plots per site were established andwere grouped according to the treatments (control forest and logged forest) for statistical analyses. We measuredand defined the following cavity tree traits potentially important for cavity-nesting birds: diameter at breastheight (DBH), cavity height, cavity entrance size and cavity internal depth. Besides, abundance and taxonomicrichness of cavity tree species were calculated, as well as functional indices: Functional Richness (FRic, amountof functional niche volume filled by cavity tree species in the community), Functional Evenness (FEve, measuresthe regularity of the distribution of cavity tree species abundances and dissimilarities in functional space),Functional Divergence (FDiv, quantifies how cavity tree species diverge in their abundance-weighted, distancesin functional space) and Community-Weighted Mean (CWM, mean of trait values present in the communityweighted by the relative abundance of species bearing each value). The main results showed that logged sites(relative to control sites) had: (1) lower abundance and taxonomic richness of cavity trees; (2) lower functionalrichness; (3) higher functional evenness, which may be due to the uniformity in distribution of the traits of thecavity tree species in space; (4) lower ?Community-Weighted Mean? of cavity size, possibly due to the fact thatlarger cavities need larger tree species and they are the most extracted in logged sites. Understanding how thefunctional traits of cavity trees are affected may help decision makers to implement sustainable policies forconservation of secondary-cavity user birds, and consequently, of the ecological services they provide.