Regulated timber harvesting does not reduce koala density in north-east forests of New South Wales

• Published in: Scientific reports 2022-03, Vol.12 (1), p.3968-3968, Article 3968
• Main Authors: Law, Brad, Gonsalves, Leroy, Burgar, Joanna, Brassil, Traecey, Kerr, Isobel, O’Loughlin, Chris, Eichinski, Phil, Roe, Paul
• Format: Article
• Language: English
• Subjects: 631/158; 704/158; 704/172; Animals; Arrays; Conservation of Natural Resources; Density; Female; Forestry; Forests; Harvest; Humanities and Social Sciences; Male; multidisciplinary; National parks; New South Wales; Phascolarctidae; Science; Science (multidisciplinary)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-022-08013-6

The compatibility of forestry and koala conservation is a controversial issue. We used a BACIPS design to assess change in koala density after selective harvesting with regulations to protect environmental values. We also assessed additional sites heavily harvested 5–10 years previously, now dominated by young regeneration. We used replicate arrays of acoustic sensors and spatial count modelling of male bellowing to estimate male koala density over 3600 ha. Paired sites in nearby National Parks served as controls. Naïve occupancy was close to 100% before and after harvesting, indicating koalas were widespread across all arrays. Average density was higher than expected for forests in NSW, varying between arrays from 0.03–0.08 males ha −1 . There was no significant effect of selective harvesting on density and little change evident between years. Density 5–10 years after previous heavy harvesting was equivalent to controls, with one harvested array supporting the second highest density in the study. Within arrays, density was similar between areas mapped as selectively harvested or excluded from harvest. Density was also high in young regeneration 5–10 years after heavy harvesting. We conclude that native forestry regulations provided sufficient habitat for koalas to maintain their density, both immediately after selective harvesting and 5–10 years after heavy harvesting.