Research Centre for Future Landscapes, La Trobe University, Melbourne, Victoria, 3086, Australia.
Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Victoria, 3086, Australia.
Ecol Appl. 2019 Dec;29(8):e01980. doi: 10.1002/eap.1980. Epub 2019 Aug 28.
Conservation managers regularly burn vegetation to regenerate habitat for fire-dependent species. When determining the time since fire at which to burn, managers model change in a species' occurrence over time, post-fire (fire-response curve) and identify the time since fire associated with decline in occurrence. However, where species exhibit variability in their fire response across space, using a single fire-response curve to determine the timing of burns may lead to burning habitat at an inappropriate time since fire. We tested if elevation, local topography, soil properties, vegetation type or evapotranspiration affect the fire response of the endangered Mallee Emu-wren Stipiturus mallee and its hummock-grass habitat Triodia scariosa in southeastern Australia (n = 217). Previous work on the Mallee Emu-wren found a unimodal fire response with decline in occurrence at ~30-50 yr since fire and a time window of occurrence of ~30 yr. We found that time since fire and elevation interact to affect the Mallee Emu-wren fire response. At high elevations (55-98 m), Mallee Emu-wrens declined in occurrence at ~50 yr since fire, with a time window of occurrence of 20-40 yr. However, at low elevations (28-55 m), Mallee Emu-wrens showed no decline in occurrence with increasing time since fire with a time window of occurrence of up to 107 yr. Extent cover of Tall T. scariosa showed similar patterns to the Mallee Emu-wren, indicating that vegetation structure is a likely driver of variability in the Mallee Emu-wren fire response. We speculate that the effect of low elevation is mediated by increased soil nutrient and water availability for key plants. We used our findings to map the appropriate time since fire at which to burn to regenerate habitat for the Mallee Emu-wren across the study region. We recommend no burning for regeneration across one-third of potential habitat, because the Mallee Emu-wren showed no decline in occurrence in these areas. We recommend managers model variability in species' fire responses across space to improve the timing of burns for regeneration.
保护管理者经常会燃烧植被，以恢复对火有依赖的物种的栖息地。在确定何时进行燃烧以更新植被时，管理者会对物种在火灾后的发生变化（火灾响应曲线）进行建模，并确定与发生频率下降相关的火灾发生时间。然而，如果物种在空间上对火灾的响应存在差异，那么使用单一的火灾响应曲线来确定燃烧时间可能会导致在不适当的时间进行燃烧。我们在澳大利亚东南部（n=217）测试了海拔、局部地形、土壤特性、植被类型或蒸散作用是否会影响濒危的矮灌丛凤鹛（Stipiturus mallee）及其矮灌丛草丛栖息地 Triodia scariosa 的火灾响应。之前关于矮灌丛凤鹛的研究发现，其火灾响应呈单峰模式，在火灾后约 30-50 年发生频率下降，发生频率的时间窗口约为 30 年。我们发现，火灾发生时间和海拔会相互作用，影响矮灌丛凤鹛的火灾响应。在高海拔地区（55-98 米），矮灌丛凤鹛在火灾后约 50 年发生频率下降，发生频率的时间窗口为 20-40 年。然而，在低海拔地区（28-55 米），随着火灾发生时间的增加，矮灌丛凤鹛的发生频率没有下降，发生频率的时间窗口可达 107 年。高大的 T. scariosa 盖度表现出与矮灌丛凤鹛相似的模式，表明植被结构是导致矮灌丛凤鹛火灾响应差异的一个可能因素。我们推测，低海拔的影响是通过增加关键植物的土壤养分和水分供应来介导的。我们利用研究结果绘制了在研究区域内为矮灌丛凤鹛再生栖息地进行燃烧的适当时间。我们建议在三分之一的潜在栖息地内不进行燃烧，因为在这些区域矮灌丛凤鹛的发生频率没有下降。我们建议管理者对物种在空间上的火灾响应差异进行建模，以提高燃烧时间的准确性，从而实现再生。
