Importance of internal refuges and the external unburnt area in the recovery of rodent populations after wildfire

Abstract

Rodent populations respond quickly to changes in habitat structure and composition resulting from disturbances such as wildfires. Rodents may recolonise burnt areas from individuals that survived the wildfire in ‘internal refuges’ or from the surrounding unburnt area (i.e. external colonisation). With the aim of assessing the relative role of both hypotheses on rodent abundance and foraging behaviour after fire, four Mediterranean burnt areas were studied using sampling stations at increasing distances from the perimeter of the burnt area. In the first 18 months after fire, the abundance of wood mice (Apodemus sylvaticus) and seed removal activity were highest near the perimeter. This suggests the weight of external sources (i.e. from unburnt areas) in the recolonisation process is higher than that of internal refuges. Algerian mice (Mus spretus) colonised the burnt areas from external sources. Vegetation cover was the most important variable affecting the relative abundance of rodents in recently burnt areas. After some months of vegetation recovery, rodent individuals that had dispersed from the unburnt area were likely to take advantage of sparsely occupied habitat with sufficient resources and, at this time, might use internal refuges. Therefore, understanding recolonisation dynamics is fundamental to anticipate biodiversity patterns and promote adaptive management.

Effects of environmental factors on the behaviour and nest group sizes of Smith's bush squirrels, Paraxerus cepapi, in a Zambezian bioregion

“…Consequently, tree cutting, resulting in loss of canopy coverage and nest site depletion, might reduce bush squirrel nest group sizes. Although rodent populations may rapidly adjust to anthropogenic disturbances (Puig-Gironès et al 2018), tree-dwelling bush squirrels are known to respond differently to habitat fragmentation (Koprowski 2005). The bush squirrel population response and their behavioural plasticity may depend on the severity of the perturbation impacts.…”

Prescribed fire enhances seed removal by ants in a Neotropical savanna

“…Fire seems to affect the bird communities most in short term in Cerrado, with some savanna specialist taxa and birds of prey probably benefiting from fire (Reis et al, 2016). Although some rodents may find refuges in burrows and nearby vegetation not affected by fire and recolonize burned sites (Puig-Gironès et al, 2018), it is likely that rodents foraging for seeds decrease in burned sites due to temporal reductions in rodent populations and increasing foraging for invertebrates (Vieira & Briani, 2013). Therefore, large seeds typically targeted by rodents may show higher survival in recently burned plots.…”

“…Fire can also affect the populations of animals that interact with seeds (van Eeden et al, 2020;Pausas & Parr, 2018;Vasconcelos et al, 2016;Vieira & Briani, 2013) and resource availability (Pilon et al, 2018). As a consequence, seed removal can sometimes decrease in burned sites, and gradually increase with recovery of rodent populations and resources to them (Puig-Gironès et al, 2018). Nevertheless, information about the effect of fire on seed removal is still limited, and we know little about how persistent are those effects under vegetation recovery after fire.…”

Bridging the Divide: Integrating Animal and Plant Paradigms to Secure the Future of Biodiversity in Fire-Prone Ecosystems

“…Plants are immobile throughout much of their life-cycle and many have endogenous means of reproduction from seedbanks or vegetative buds that promote in situ persistence after a fire [6]. Individual animals are more mobile and some can survive fires by moving to refuges or recolonize from surrounding areas after being extirpated from burnt areas [7]. Some differences in management and research are also likely to stem from the separate developments of the animal and plant sciences.…”