Smith Annabel L, Lim Amber Shuo Ying
School of the Environment, University of Queensland, St Lucia, Queensland, Australia.
Ecology. 2025 Jun;106(6):e70121. doi: 10.1002/ecy.70121.
Fire responses in animal communities have been well studied, but little is known about the effects of fire on rare species due to limitations in data and modeling frameworks. Using a suite of methods to account for rarity, dominance, and incomplete sampling, we aimed to determine how post-fire succession influenced locally rare and cryptic reptile species in semiarid mallee woodlands in southern Australia. Contemporary fires in this system are typically high-intensity wildfires or prescribed fires, which raze aboveground vegetation. Reptiles were sampled from pitfall traps over two summer seasons (1400 trap nights) at 14 sites spanning three fire history categories based on time since the last fire: recently burnt (2-3 years post fire), medium (7-9 years), and long unburnt (42-48 years). The data comprised 2138 individual reptiles from 41 species. The effects of fire history were evident in diversity metrics where proportional abundances were weighted toward rare species (Shannon's Diversity, Fisher's α), but not in those emphasizing common species (Simpson's Diversity, Berger-Parker Index) or species richness. There were no effects of fire history on the richness or abundance of locally rare species when examined directly. However, fire effects on rare species diversity were detectable in one sub-assemblage including 20 species with fewer than eight total observations. This result indicated higher diversity in unburnt habitat; an effect that was masked when numerically dominant species were included in the analysis. When accounting for incomplete sampling using rarefaction and extrapolation, unburnt habitat was more diverse, accumulated species more quickly, and required a greater sampling effort to obtain sample coverage comparable to recently burnt and medium habitat. Overall, common and abundant reptile species appeared to dominate recently burnt and mid-succession habitats, while reptile communities in long unburnt habitat were more diverse because they had more rare or cryptic species. The data suggest that responses of rare species to fire history are harder to detect than common, dominant species which are often favored by disturbance (and scientific research). Fire management which maintains some early- and mid-successional habitat, while strategically conserving unburnt habitat, should benefit rare and cryptic reptile species in this system.
动物群落中的火灾响应已得到充分研究，但由于数据和建模框架的限制，关于火灾对珍稀物种的影响却知之甚少。我们运用一系列方法来考量物种的稀有性、优势度和不完全采样情况，旨在确定火灾后的演替如何影响澳大利亚南部半干旱马利桉树林中当地的珍稀和隐秘爬行动物物种。该系统中的当代火灾通常是高强度野火或计划性火烧，会将地上植被夷为平地。我们在两个夏季（1400个陷阱夜），于14个地点设置陷阱捕获爬行动物，这些地点基于距上次火灾的时间分为三类火灾历史类别：近期火烧（火灾后2 - 3年）、中度火烧（7 - 9年）和长期未火烧（42 - 48年）。数据包括来自41个物种的2138只个体爬行动物。火灾历史的影响在多样性指标中很明显，在这些指标中，比例丰度偏向珍稀物种（香农多样性、费希尔α指数），但在强调常见物种的指标（辛普森多样性、伯杰 - 帕克指数）或物种丰富度中则不明显。直接考察时，火灾历史对当地珍稀物种的丰富度或丰度没有影响。然而，在一个包含20个物种且总观测次数少于8次的子组合中，可检测到火灾对珍稀物种多样性的影响。这一结果表明未火烧栖息地的多样性更高；当分析中纳入数量上占优势的物种时，这种影响被掩盖了。当使用稀疏化和外推法来考虑不完全采样时，未火烧栖息地更加多样，物种积累更快，并且需要更大的采样力度才能获得与近期火烧和中度火烧栖息地相当的样本覆盖率。总体而言，常见且数量众多的爬行动物物种似乎在近期火烧和演替中期的栖息地中占主导地位，而长期未火烧栖息地中的爬行动物群落更加多样，因为它们有更多珍稀或隐秘物种。数据表明，珍稀物种对火灾历史的响应比常见的优势物种更难检测，而常见的优势物种往往受到干扰（以及科学研究）的青睐。维持一些早期和中期演替栖息地，同时战略性地保护未火烧栖息地的火灾管理措施，应该会使该系统中的珍稀和隐秘爬行动物物种受益。
