Morphometric, health and demographic status of koalas in a fragmented agricultural landscape

Koalas are endangered iconic Australian species susceptible to anthropogenic disturbances and climate change, particularly in fragmented landscapes. This arboreal folivore inhabits diverse landscapes, including agricultural land where conservation challenges are frequent and exacerbated by a general lack of area-specific biological information. This study aimed to determine the demographic, morphometric, and health attributes of koalas inhabiting agricultural land. A total of 43 koalas (21 males and 22 females) were captured and examined using standard approaches near Pittsworth, Queensland, Australia. The examination process comprised morphometric measurements, physical examination, ultrasound assessment, and the collection of blood and swab samples, which were subsequently analysed in laboratories. Findings revealed an even sex ratio of koalas with a broad age structure inclusive of many females accompanied by joeys indicating high fecundity in the study area. Morphometric measurements were comparable with koalas from other regions of Queensland, and haematological and serum parameters were within the optimum range. However, the prevalence of chlamydiosis in this population of koalas was 44% (n=19). The high prevalence of chlamydial disease and koalas’ complete reliance on unprotected habitat indicates that their longer-term viability in such landscapes is tenuous. Future conservation programs should aim to protect and connect suitable habitat within fragmented agricultural landscapes and prioritise monitoring health dynamics of koala populations.