Responses of functional traits in cavity-nesting birds to logging in subtropical and temperate forests of the Americas

Abstract

Logging causes changes in habitat structure, which can potentially lead to variations in taxonomic and functional richness of biodiversity. Studies on how functional traits in birds are affected by logging operations can provide an important element for the understanding of ecosystem processes. In this paper, we examined how logging in subtropical Andean forests influenced taxonomic and functional diversity of cavity-nesting birds. We used these results to compare how logging affected ecosystem functions in temperate and subtropical forests of the Americas. We used point-counts to examine the effects of logging on taxonomic and functional traits in avian communities (Functional Richness, Functional evenness, Functional Divergence, and Community-weighted mean). We found that logging changed bird richness and abundance, although it had no effect on the functional response to the measured traits. The comparison of our results with those of temperate forests of Canada and Chile reveals differences in the functional richness of birds in these habitats, with a lower impact of logging on functional traits. We highlight the importance of including functional traits in the analyses, since the reduction in the species richness and abundance may not be translated into functional changes within the ecosystem.

Figure 1

Location of the study sites in subtropical piedmont forests of northwestern Argentina: unlogged (green) and logged (red) forest sites are depicted on the map. Total tree species and habitat variables measured are also shown. This figure was produced using QGIS version 3.20.2 (https://www.qgis.org/).

Figure 2

Functional richness and diversity in both temperate forests in Canada and Chile and subtropical forests in Argentina. The number of bird species and species richness for each site is also noted above: distinct letters indicate differences in the mean values between treatments. Functional diversity indices measured in all sites (below) and significant differences in mean values between treatments (*) are also depicted. This figure was produced using INFOSTAT software (//www.infostat.com.ar).