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 functionalecology have increased in the last years and they are currently an importantelement for the understanding of ecosystem processes. The aim of this study wasto compare different functional traits of cavity trees for secondarycavity-nesting birds, between unlogged (control forest) and conventionallylogged sites in subtropical piedmont forests of NW Argentina. Between 10 and 20plots per site were established and were grouped according to the treatments(control forest and logged forest) for statistical analyses. We measured and definedthe following cavity tree traits potentially important for cavity-nestingbirds: diameter at breast height (DBH), cavity height, cavity entrance size andcavity internal depth. Besides, abundance and taxonomic richness of cavity treespecies 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, measures the regularity of the distribution ofcavity tree species abundances and dissimilarities in functional space), FunctionalDivergence (FDiv, quantifies how cavity tree species diverge in theirabundance-weighted, distancesin functional space) and Community-Weighted Mean (CWM, mean of trait valuespresent in the community weighted by the relative abundance of species bearingeach value). The main results showed that logged sites (relative to controlsites) had: (1) lower abundance and taxonomic richness of cavity trees; (2)lower functional richness; (3) higher functional evenness, which may be due tothe uniformity in distribution of the traits of the cavity tree species inspace; (4) lower ?Community-Weighted Mean? of cavity size, possibly due to thefact that larger cavities need larger tree species and they are the mostextracted in logged sites. Understanding how the functional traits of cavitytrees are affected may help decision makers to implement sustainable policiesfor conservation of secondary-cavity user birds, and consequently, of theecological services they provide.