Long-unburnt habitat is critical for the conservation of threatened vertebrates across Australia

Abstract

Context Increases in fire frequency, intensity and extent are occurring globally. Relative to historical, Indigenous managed conditions, contemporary landscapes are often characterised by younger age classes of vegetation and a much smaller representation of long-unburnt habitat. Objectives We argue that, to conserve many threatened vertebrate species in Australia, landscape management should emphasise the protection of existing long-unburnt patches from fire, as well as facilitate the recruitment of additional long-unburnt habitat, while maintaining historically relevant age distributions of more recently burned patches. Methods We use a range of case studies and ecosystem types to illustrate three lines of evidence: (1) that many threatened vertebrate species depend on mid- to late-successional ecosystem attributes; (2) disturbance to long-unburnt habitat tends to increase risk of future disturbance and ecosystem collapse; and (3) contemporary landscapes exhibit a range of characteristics that differ to historical conditions and require context-specific management. Conclusions It is crucial that we adequately consider the implications of altered contemporary landscapes for management activities that aim to conserve threatened vertebrates. Contemporary landscapes often lack a range of critical structural and compositional components typical of late-successional habitat that are required for the persistence of threatened vertebrates. We need to shift towards strategic, objective-driven approaches that identify and protect long-unburnt habitats and promote their recruitment to enable recovery of many declining and threatened species.

Population genomics and conservation management of the threatened black-footed tree-rat (Mesembriomys gouldii) in northern Australia

“…Conservation actions that may benefit the black-footed tree-rat include targeted early season prescribed burning, to prevent high-intensity late dry season fires that reduce habitat integrity (e.g., retention of hollow bearing and fruiting shrubs), and greater retention of old growth vegetation (i.e., 4 years at unburnt) in close proximity to known populations (von Takach et al 2020 a, 2020 b; Radford et al 2021 ; von Takach et al 2022 ). Conserving genetic diversity in a captive breeding program could also be pursued, as has been done for other Australian rodents (Lambert et al 2016 ; Abicair et al 2020 ), to supplement wild populations with captive-reared individuals or act as an insurance population.…”

Habitat structure facilitates coexistence of native and invasive mesopredators in an Australian tropical savanna

“…Given that the eradication of the cat is not currently feasible across unfenced landscapes, the maintenance of complex habitat may be one of the few ways to mitigate cat impacts on native mammals across northern Australia. Fire regimes appear to be a crucial factor determining whether populations of small mammals are able to persist in the extremely fire-prone savannas of northern Australia (Griffiths and Brook 2014;von Takach et al 2022). Reductions in the frequency of fires, especially those of high intensity, can promote the persistence of large hollow-bearing trees (Williams et al 1999;Edwards et al 2018;Woolley et al 2018) and potentially suppress cat activity (Davies et al 2020;Stobo-Wilson et al 2020b).…”

Quantifying the impacts of an invasive weed on habitat quality and prey availability for tiger snakes (Notechis scutatus) in urban wetlands

“…The domination of an environment by a monoculture of a single invasive grass can have adverse effects on the ecosystem. For example, the invasion of gamba ( Andropogon gayanus ) and para ( Urochloa mutica ) grasses in northern Australia results in higher fuel loads and higher intensity fires than in uninvaded habitats, due to higher biomass and lower moisture content of the invasive species (Rossiter et al 2003, Douglas and O’Connor 2004, von Takach et al 2022). The most common impact of habitat structural homogeneity from invasive grasses, however, is the loss of native plant (Stephens et al 2008), invertebrate (Douglas and O’Connor 2003) and vertebrate (Cook and Grice 2013, Stanton et al 2018) biodiversity – largely attributed to a loss of suitable habitat usually provided by structurally complex vegetation communities.…”