A field test of mechanisms underpinning animal diversity in recently burned landscapes

1. Planned burning generates different types of pyrodiversity, however,
experimental tests of how alternative spatial patterns of burning
influence animal communities remain rare. Field tests are needed to
understand the mechanisms through which spatial variation in planned fire
affects fauna, and how fire can be applied to benefit biodiversity. 2. We
tested five hypotheses of how fire-driven variation in habitat composition
and configuration affects fauna at fine scales. Small mammal, reptile and
invasive predator activity was monitored at 12 burnt and eight unburnt
sites through the year following a large, planned burn in semi-arid
‘mallee’ woodlands of southern Australia. We explored measures of burnt or
unburnt habitat (“habitat status”); amount of unburnt vegetation (“habitat
amount”); interspersion of burnt and unburnt patches (“habitat
complementation”); distance to external or internal unburnt vegetation
(“habitat connectivity”); and unburnt patch size and local vegetation
cover (“habitat refuge”). Generalized linear models were used to test the
influence of each variable on capture rate of three small mammal and 11
reptile species; activity of the introduced red fox (Vulpes vulpes); and
species richness of native animals. 3. We found strong support for the
habitat status hypothesis and moderate support for four hypotheses
relating to spatial patterns of fire. Reptile assemblages varied between
burnt and unburnt sites, and relationships were identified between
abundance of one or more reptile species and each measure of spatial
variation. Reptile species richness was higher at unburnt sites and at
sites with more unburnt vegetation in the surrounding area. Sites that
were less connected to unburnt vegetation had fewer reptile species.
Mammals did not have clear relationships with fine-scale fire patterns. 4.
Synthesis and applications: Application of planned fire to promote
biodiversity is globally important. We show that retaining unburnt areas
and well-connected habitat refuges is important for reptile diversity. We
also found that several species of small mammals and reptiles appear
resilient to the fine-scale patterns of planned fire experienced in this
study, despite activity of introduced predators. The diversity of animals
can remain relatively high in areas subject to planned fire, provided that
internal and external habitat refuges are retained.