Laying low: Rugged lowland rainforest preferred by feral cats in the Australian wet tropics

Invasive mesopredators are responsible for the decline of many species of
native mammals worldwide. Feral cats have been causally linked to multiple
extinctions of Australian mammals since European colonisation. While feral
cats are found throughout Australia, most research has been undertaken in
arid habitats, thus there is a limited understanding of feral cat
distribution, abundance, and ecology in Australian tropical rainforests.
We carried out camera-trapping surveys at 108 locations across seven study
sites, spanning 200 km in the Australian Wet Tropics. 
Single-species occupancy analysis was implemented to investigate how
environmental factors influence feral cat distribution. Feral cats were
detected at a rate of 5.09 photographs/100 days, 11 times higher than
previously recorded in the Australian Wet Tropics. The main environmental
factors influencing feral cat occupancy were a positive association with
terrain ruggedness, a negative association with elevation, and a higher
affinity for rainforest than eucalypt forest. These findings were
consistent with other studies on feral cat ecology but differed from
similar surveys in Australia. Increasingly harsh and consistently wet
weather conditions at higher elevations, and improved shelter in
topographically complex habitats may drive cat preference for lowland
rainforest. Feral cats were positively associated with roads, supporting
the theory that roads facilitate access and colonisation of feral cats
within more remote parts of the rainforest. Higher elevation rainforests
with no roads could act as refugia for native prey species within the
critical weight range. Regular monitoring of existing roads should be
implemented to monitor feral cats, and new linear infrastructure should be
limited to prevent encroachment into these areas. This is pertinent as
climate change modelling suggests that habitats at higher elevations will
become similar to lower elevations, potentially making the environment
more suitable for feral cat populations.