Pyrodiversity and biodiversity: A history, synthesis, and outlook

Abstract

Aim Pyrodiversity is the spatial or temporal variability in fire effects across a landscape. Multiple ecological hypotheses, when applied to the context of post‐fire systems, suggest that high pyrodiversity will lead to high biodiversity. This resultant “pyrodiversity–biodiversity” hypothesis has grown popular but has received mixed support by recent empirical research. In this paper, we sought to review the existing pyrodiversity literature, appraise support for the pyrodiversity–biodiversity hypothesis, examine potential mechanisms underlying the hypothesis and identify outstanding questions about pyrodiversity and future research needs. Location Global terrestrial ecosystems. Methods We performed a systematic literature review of research related to pyrodiversity and the pyrodiversity–biodiversity hypothesis. We also examined how two individual species with distinct relationships with fire (spotted owl Strix occidentalis and black‐backed woodpecker Picoides arcticus) respond to pyrodiversity as case studies to illustrate underlying mechanisms. Results We identified 41 tests of the pyrodiversity–biodiversity hypothesis reported from 33 studies; 18 (44%) presented evidence in support of the pyrodiversity–biodiversity hypothesis, while 23 (56%) did not. Our literature review suggested that support for the pyrodiversity–biodiversity hypothesis varies considerably with no consistent patterns across taxonomic groups and ecosystem types. Studies examining the pyrodiversity–biodiversity hypothesis often define pyrodiversity in different ways, examine effects at different scales and are conducted in ecosystems with different natural fire regimes, baseline levels of biodiversity, and evolutionary histories. We suggest these factors independently and jointly have led to widely varying support for the pyrodiversity–biodiversity hypothesis. Main Conclusions Clarifying the pyrodiversity–biodiversity hypothesis will be facilitated by stronger development of the different potential mechanisms underlying pyrodiversity–biodiversity relationships, which can be aided by examining how individual species respond to pyrodiversity. Future research would benefit from a closer examination of the role of scale (e.g. scale dependence) in pyrodiversity–biodiversity relationships, standardization of pyrodiversity metrics, broad‐scale mapping of pyrodiversity, and macroecological study of pyrodiversity–biodiversity relationships.

Fire mosaics in south-west Australian forest landscapes

“…As a consequence of anthropogenic burning and lightning-caused fires, south-west Australian landscapes persisted as a mosaic of patches of vegetation at different seral (time since fire) stages, although details about the spatial and temporal characteristics of the mosaics are unknown. There is on-going debate about the biodiversity benefits of managing flammable wildlands to achieve a fine-scale mosaic of patches of vegetation at different seral stages (Jones and Tingley 2021). Some argue that it benefits the biota (e.g.…”

“…2000) and is an important characteristic in its own right because of interactions and feedback loops with disturbances such as fire. Although there have been several taxon-specific studies, it is unclear what the most appropriate fire mosaic should be for optimising biodiversity at the landscape scale in different biomes (Bradstock et al 2005;Parr and Andersen 2006;Clarke 2008;Driscoll et al 2010;Kelly et al 2012;Jones and Tingley 2021).…”

Analysing How Pre-Fire Habitat Legacy and Post-Fire Management Influence the Resilience of Reptiles to Fire

“…In the temporal sense, wildfire plays a key role in forest dynamics shaping biodiversity composition from microbial to vertebrate communities along the post-fire succession [3,4]. Spatially, fire regimes may lead to heterogeneous landscapes with a mosaic of burnt and unburnt patches at different times after a fire [5]. In recent decades, wildfires have changed in frequency, extent, and severity in many regions worldwide [6], giving rise to a fire regime shift that is threatening biodiversity [2].…”

Landscape-Scale Effects of Fire, Cats, and Feral Livestock on Threatened Savanna Mammals: Unburnt Habitat Matters More Than Pyrodiversity

“…The benefits therefore of establishing an intermediate extent (25%) of recent fire within mosaics, is in maintaining longer unburnt habitat refugia within the savanna matrix. Our study joins an increasing number of ecological studies which do NOT support a general finding that 'pyrodiversity begets biodiversity' (Jones and Tingley, 2021). Future studies need to move beyond simplistic ideas concerning pyrodiversity and biodiversity, and focus more on the key functional elements within fire mosaics which mechanistically support target species with particular ecological traits, if progress is to be made in use of prescribed fire mosaics for threatened species conservation.…”

“…Here, we test the following hypotheses: (1) That mammal abundance and richness is highest with increasing site-scale ground layer habitat cover/complexity , Radford et al, 2020aDavies et al, 2017Davies et al, , 2020Stobo-Wilson et al, 2020a); (2) that mammal abundance and richness is highest at sites where predator (feral cat and dingo), fire and cattle 'disturbance' is least prevalent or abundant (McGregor et al, 2014(McGregor et al, , 2015(McGregor et al, , 2016Lawes et al, 2015;Leahy et al, 2016;Stobo-Wilson et al, 2020a,b;Shaw et al, 2021); (3) that site-and local-scale fire mosaic attributes will be more influential on mammal abundance and richness than broader landscape-or subregional-scale mosaic attributes due to recolonization/dispersal limitations for some mammal species (Leahy et al, 2016;Shaw et al, 2021); and (4) the most important attributes of local and landscape fire mosaics will be presence of longer unburnt habitat based on previous observations (e.g., Legge et al, 2008;, Radford et al, 2020a and that pyrodiversity (diversity of post-fire habitat age) will be positively associated with mammal abundance and richness based on patch mosaic burning theory (critiques by Parr and Andersen, 2006;Jones and Tingley, 2021).…”