Faunal Responses to Fire in Chaparral and Sage Scrub in California, USA

Elizabeth F Van Mantgem,Jon E Keeley,Marti Witter

doi:10.4996/fireecology.1103128

Elizabeth F Van Mantgem, Jon E Keeley + Show 1 more

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https://doi.org/10.4996/fireecology.1103128

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Abstract

AbstractImpact of fire on California shrublands has been well studied but nearly all of this work has focused on plant communities. Impact on and recovery of the chaparral fauna has received only scattered attention; this paper synthesizes what is known in this regard for the diversity of animal taxa associated with California shrublands and outlines the primary differences between plant and animal responses to fire. We evaluated the primary faunal modes of resisting fire effects in three categories: 1) endogenous survival in a diapause or diapause-like stage, 2) sheltering in place within unburned refugia, or 3) fleeing and recolonizing. Utilizing these patterns in chaparral and sage scrub, as well as some studies on animals in other mediterranean-climate ecosystems, we derived generalizations about how plants and animals differ in their responses to fire impacts and their postfire recovery. One consequence of these differences is that variation in fire behavior has a much greater potential to affect animals than plants. For example, plants recover from fire endogenously from soil-stored seeds and resprouts, so fire size plays a limited role in determining recovery patterns. However, animals that depend on recolonization of burned sites from metapopulations may be greatly affected by fire size. Animal recolonization may also be greatly affected by regional land use patterns that affect colonization corridors, whereas such regional factors play a minimal role in plant community recovery. Fire characteristics such as rate of spread and fire intensity do not appear to play an important role in determining patterns of chaparral and sage scrub plant recovery after fire. However, these fire behavior characteristics may have a profound role in determining survivorship of some animal populations as slow-moving, smoldering combustion may limit survivorship of animals in burrows, whereas fast-moving, high intensity fires may affect survivorship of animals in aboveground refugia or those attempting to flee. Thus, fire regime characteristics may have a much greater effect on postfire recovery of animal communities than plant communities in these shrubland ecosystems.

Highlights

Chaparral and sage scrub shrublands in California, USA, are two of the highest diversity plant communities in the world (Richerson and Lum 1980)
We suggest that the diversity of animal responses to fire can be conveniently categorized into one of three types: 1) insect diapause stages such as eggs and pupae are dormant in the soil at the time of fire and lead to rapid postfire regeneration much the way plant seed banks germinate after fire; 2) animals may seek refuge in burrows, rock outcrops, randomly unburned patches, or fire-resistant riparian areas; or 3) they either flee the fire or succumb to it and must recolonize from outside the burn perimeter
There is little direct evidence for this fire survival strategy in other arthropod species; based on life histories, it is likely that it applies to many others

Summary

INTRODUCTION

Chaparral and sage scrub shrublands in California, USA, are two of the highest diversity plant communities in the world (Richerson and Lum 1980). As the vegetation recovers, the animal community composition changes with it, and this may be an on-going process for a decade or more Generalizations at this stage are few; for example, one study showed that even as the initially inflated deer mouse population decreased with plant succession, the postfire abundance of the open-habitat-specialist kangaroo rat continued to rise, doubling from 24 to 43 months after the 2003 Cedar Fire in southern California (Diffendorfer et al 2012). Schuette et al (2014) reported results similar to Turschak et al (2010) They observed postfire carnivore numbers from 27 to 43 months after the massive 2003 Cedar Fire in San Diego County and were unable to detect significant differences in occuvan Mantgem et al.: Faunal Response to Fire in California Page 139 pancy between unburned and burned plots in gray fox, striped skunk, and bobcat. This study illustrates that, as habitat fragments deteriorate over time, the resilience of large mammals to fire is further impaired

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