Effects of forest structure and human influence on the call rate of owls in the Piedmont Forest of Northwestern Argentina

SCHEFFER MAILA; POLITI NATALIA; MARTINUZZI SEBASTIÁN; RIVERA LUIS OSVALDO

Neotropical Biodiversity

Taylor and Francis

Año: 2022 vol. 9 p. 1 - 9

Owls(Strigiformes) play an important ecological role as predators that structureand organize biological communities. Specialized owl species dependent onold-growth forests have suffered declines because of forest loss or degradationby human activities. Few studies have been conducted on Neotropical owls,especially in the Piedmont Forest of Northwestern Argentina. The scarcity ofinformation on habitat requirements and the effect of human impacts precludethe establishment of conservation and management activities. The humanfootprint index (HFI) is a tool for mapping human impacts on biodiversity thatis used at global and regional scales, based on the estimated and standardizedcontribution of different human impact variables (e.g. road networks, urbancenters, agricultural land, etc.). The objectives of this work were to: 1)Determine the call rate of five owl species in the Piedmont Forest ofNorthwestern Argentina, 2) relate forest structure to the call rate of owlspecies, and 3) relate human footprint index to the call rate of owls. Weplaced 28 automatic recorders in the Piedmont Forest, in sites with low andhigh Human influence, and characterized the forest structure around eachrecorder within a circular plot of 25 m diameter. We obtained 241 vocalizationsin 168 intervals of 2 h for Ferruginous pygmy owl (Glaucidium brasilianum),Tropical screech-owl (Megascops choliba), Black-banded owl (Ciccaba huhula),Spectacled owl (Pulsatrix perspicillata), and Buff-fronted owl (Aegoliusharrisii). We found that for Tropical screech-owl live tree basal area had apositive and diameter at breast height standard deviation had a negativeinfluence on call rate. While for Black-banded owl, the dead tree density had apositive and human footprint index >1 had a negative influence on call rate.For Spectacled owl, dead tree density and human footprint index >1 had anegative influence on call rate. We provide first insights into the effects offorest structure and human influence on the call rate of owls in the PiedmontForest of Northwestern Argentina, information that may guide forest managementguidelines and conservation strategies.