Resilience of reptiles to megafires

Abstract

Extreme climate events, together with anthropogenic land‐use changes, have led to the rise of megafires (i.e., fires at the top of the frequency size distribution) in many world regions. Megafires imply that the center of the burnt area is far from the unburnt; therefore, recolonization may be critical for species with low dispersal abilities such as reptiles. We aimed to evaluate the effect of megafires on a reptile community, exploring to what extent reptile responses are spatially shaped by the distance to the unburnt area. We examined the short‐term spatiotemporal response of a Mediterranean reptile community after two megafires (>20,000 ha) that occurred in summer 2012 in eastern Spain. Reptiles were sampled over 4 years after the fire in burnt plots located at different distances from the fire perimeter (edge, middle, and center), and in adjacent unburnt plots. Reptile responses were modeled with fire history, as well as climate and remotely sensed environmental variables. In total, we recorded 522 reptiles from 12 species (11 species in the burnt plots and nine in the unburnt plots). Reptile abundance decreased in burnt compared with unburnt plots. The community composition and species richness did not vary either spatially (unburnt and burnt plots) or temporally (during the 4 years). The persistence of reptiles in the burnt area supported their resilience to megafires. The most common lizard species was Psammodromus algirus; both adults and juveniles were found in all unburnt and burnt plots. This species showed lower abundances in burnt areas compared with the unburnt and a slow short‐term abundance recovery. The lizard Psammodromus edwarsianus was much less abundant and showed a tendency to increase its abundance in burnt plots compared with unburnt plots. Within the megafire area, P. algirus and P. edwarsianus abundances correlated with the thermal–moisture environment and vegetation recovery regardless of the distance from the fire edge. These results indicated the absence of a short‐term reptile recolonization from the unburnt zone, demonstrating that reptiles are resilient (in situ persistence) to megafires when environmental conditions are favorable.

What do you mean, ‘megafire’?

“…When European authors provided a size threshold, it was typically smaller than that proposed by authors from North America and Oceania (Figure 3). Some studies defined megafires statistically relative to a region‐specific baseline (e.g., Pausas & Keeley, 2021; Santos et al., 2022). For instance, Khorshidi et al.…”

Fire severity influences the post‐fire habitat structure and abundance of a cool climate lizard

“…One explanation for the lower abundances of E. tympanum at high severity burnt sites is that lizards were directly killed by the fire and failed to recolonize post fire. However, previous studies, including on the closely related Blue‐mountains water skink ( Eulamprus leuraensis ), have concluded that lizards are somewhat resilient to being directly killed by wildfires (Costa et al, 2013; Gorissen et al, 2015; Santos et al, 2022). Furthermore, our data show that many large logs remained after the fires on sites that were burnt at high severity, and that fire severity had no effect on the volume of coarse debris.…”

A demographic framework for understanding fire‐driven reptile declines in the ‘land of the lizards'

“…The 2019–2020 ‘megafires’ in south‐eastern Australia, for instance, burnt more than 7 million hectares (Bowman et al, 2021) and were unprecedented in terms of area burnt at high severity (Collins et al, 2021). Although reptile communities might be resilient to some large fires, or even megafires (Santos et al, 2021), extremely large, intense and fast‐moving fire events can potentially cause high mortality (Nimmo et al, 2021; Tomas et al, 2021) and widespread alteration of reptile habitats (Santos et al, 2021; Ward et al, 2020).…”