Ecosystem engineers directly or indirectly affect the availability of resources through changing the physical state of biotic and/or abiotic materials. Fossorial ecosystem engineers have been hypothesized as affecting fire behaviour through altering litter accumulation and breakdown, however, little evidence of this has been shown to date. Fire is one of the major ecological processes affecting biodiversity globally. Australia has seen the extinction of 29 of 315 terrestrial mammal species in the last 200 years and several of these species were ecosystem engineers whose fossorial actions may increase the rate of leaf litter breakdown. Thus, their extinction may have altered the rate of litter accumulation and therefore fire ignition potential and rate of spread. We tested whether a reduction in leaf litter was associated with sites where mammalian ecosystem engineers had been reintroduced using a pair-wise, cross-fence comparison at sites spanning the Australian continent. At Scotia (New South Wales), Karakamia (Western Australia) and Yookamurra (South Australia) sanctuaries, leaf litter mass (À24%) and percentage cover of leaf litter (À3%) were significantly lower where reintroduced ecosystem engineers occurred compared to where they were absent, and fire behaviour modelling illustrated this has substantial impacts on flame height and rate of spread. This result has major implications for fire behaviour and management globally wherever ecosystem engineers are now absent as the reduced leaf litter volumes where they occur will lead to decreased flame height and rate of fire spread. This illustrates the need to restore the full suite of biodiversity globally.

Species extinction has reached unprecedented rates globally, and can cause unexpected ecological cascades. Since Europeans arrived in Australia, many endemic mammals have declined or become extinct, but their ecological roles and outcomes of their reintroduction for ecosystems are poorly understood. Using surveys and novel long‐term exclusion and disturbance experiments, we tested how digging mammal reintroduction affects predatory invertebrates. Mammal exclusion tended to decrease bare ground. Although scorpion burrow abundance increased with bare ground, mammals also had direct negative effects on scorpions. Increased disturbance alone decreased scorpion abundance, but other mechanisms, such as predation, also contributed to the mammal effect. Despite negative associations between scorpions and spiders, both groups increased and spider composition changed following mammal exclusion. Our long‐term research showed that threatened digging mammals drive ecosystem cascades, affecting biota through a variety of pathways. Reintroductions of locally extinct digging mammals can restore ecosystems, but ecosystem cascades may lead to unexpected restructuring.

Species extinctions and declines are occurring globally and commonly have cascading effects on ecosystems. In Australia, mammal extinctions have been extensive, particularly in arid areas, where precipitation drives ecosystems. Many ecologically extinct mammals feed on soil-dwelling insects. However, how this topdown pressure affected their prey and how this contrasts with the bottom-up impacts of fluctuating precipitation remains unclear. We constructed a long-term exclusion experiment in a multi-species mammal reintroduction zone in semi-arid Australia to test how top-down (reintroduced mammals) and bottom-up (precipitation) factors affect root-feeding chafer beetles (Coleoptera: Melolonthinae). We used emergence traps in ten replicate 20 9 20 m plots of control, exclusion and procedural control treatments to trap chafers biannually from 2009 to 2015. Annual precipitation during this period varied from 173 to 481 mm. Mammal exclusion did not affect chafers, indicating that top-down regulation was not important. Instead, chafer abundance, species density and biomass increased with precipitation. Chafer body size and assemblage composition were best predicted by sampling year, suggesting that random drift determined species abundances. Increased resource availability therefore favoured all species similarly. We thus found no evidence that mammal predation alters chafer populations and conclude that they may be driven primarily by bottom-up processes. Further research should determine if the cascading effects of species loss are less important for herbivores generally than for higher level trophic groups and the role of ecosystem stability in mediating these patterns.

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This article is corrected by: Errata: Erratum for ‘Could biodiversity loss have increased Australia's bushfire threat?’ and ‘The implications of biodiversity loss for the dynamics of wildlife in Australia’ | Volume 20, Issue 2, 213, Article first published online: 3 April 2017

This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Invasive mesopredators, particularly feral cats, are responsible for the decline of many species of native mammals worldwide. In Australia, there is currently limited understanding of the drivers of feral cat occupancy in tropical rainforests, the most biodiverse ecosystem in the continent. We carried out camera-trapping surveys at 108 sites across eight study sites. Camera-trap pairs were placed at 2.2km intervals along roads, with one camera-trap facing the road and another 50m into the forest to ensure that individuals who prefer or avoid roads could be detected. Single-species occupancy analysis was implemented to investigate how environmental factors influence feral cat distribution in the Australian Wet Tropics. There were 524 independent feral cat detections, 11 times higher than previously recorded in the Australian Wet Tropics. The main environmental factors influencing feral cat distribution were a positive association with terrain ruggedness, a negative association with elevation, and a higher affinity for rainforest than eucalypt forest. These findings were congruent with global studies on feral cat ecology but disagreed with similar surveys within Australia. Understory complexity is reduced in rugged terrain, which could improve feral cats’ hunting efficiency, while increasingly harsh and consistently wet weather conditions at higher elevations drive their preference for lowland rainforest. Feral cats were heavily associated with roads, supporting the theory that roads facilitate access and proliferation of feral cats within more remote parts of the rainforest. Higher elevation rainforest 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.