Sex-based differences in the use of post-fire habitats by invasive cane toads (Rhinella marina)

Wildfires can modify habitat attributes, and those changes may differentially affect males versus females within a species if there is pre-existing niche divergence between the sexes. We used radio-tracking and dissections to study invasive cane toads (Rhinella marina), and performed transect counts on native frogs and cane toads 12 months after extensive fires in forests of eastern Australia. Both toads and native frogs were encountered more frequently in burned sites than in unburned sites. Most microhabitat features were similar between burned versus unburned areas, but fire had differential impacts on the ecology of male versus female toads. In burned areas females were less numerous but were larger, in better body condition, and had consumed more prey (especially, coleopterans and myriapods). The impact of fire on attributes of retreat-sites (e.g., temperature, density of vegetation cover) also differed between the sexes. More generally, intraspecific divergence in ecological traits within a species (as a function of body size as well as sex) may translate into substantial divergences in the impacts of habitat change.

野火可改变生境属性，若物种内两性间预先存在生态位分化，则此类生境变化可能对雌雄个体产生差异化影响。本研究通过无线电追踪与解剖手段，对入侵性蔗蟾（Rhinella marina）展开研究，并在澳大利亚东部林区发生大规模火灾12个月后，对本土蛙类与蔗蟾开展样带计数调查。结果显示，相较于未过火区域，过火区域内蔗蟾与本土蛙类的遇见率均更高。尽管过火与未过火区域的多数微生境特征无显著差异，但火灾对雌雄蔗蟾的生态学特征产生了差异化影响：在过火区域内，雌性蔗蟾种群密度更低，但个体体型更大、身体状况更佳，且捕食量更高（尤其偏好鞘翅目昆虫与多足类动物）。此外，火灾对休憩场所属性（如温度、植被覆盖度）的影响同样存在两性差异。从更宏观的视角来看，物种内生态特征的种内分化（受体型与性别共同调控），可能会导致生境变化所产生的影响出现显著分化。