Data from: Prescribed burning protects endangered tropical heathlands of the Arnhem Plateau, northern Australia

1. There are concerns that frequent intense fires are reducing biodiversity on the Arnhem Plateau within Kakadu National Park, northern Australia. Since the 1980s, prescribed burning in the early dry season has aimed to reduce the extent of late dry season wildfires. A programme of more strategic prescribed burning has been undertaken since 2007, aiming to increase intervals between fires affecting heathland and rain forest communities. 2. We assess the effectiveness of prescribed burning in Kakadu's Stone Country using a Landsat satellite-derived fire history (1980–2011), in terms of achieving ‘tolerable fire intervals’ for dominant plant communities. 3. Our analysis indicates that fire regimes have become substantially more favourable for biodiversity since the early 1980s. Although annual extent of burning has remained unchanged, two significant changes in fire regimes have occurred over the long term: (i) a switch from late dry season dominance to early dry season dominance and (ii) an increase in the abundance of long-unburnt vegetation, both of which are likely to benefit biodiversity. Demonstrating the statistical significance of changes associated with recent, more strategic fire management (2007–2011) is limited by the short duration of this management approach, although there is evidence of increasing abundance of long-unburnt vegetation during this time. 4. The view that the Arnhem Plateau's fire regimes are increasingly driving biodiversity loss (due to frequent late dry season wildfires) is erroneous; they are in a more benign state now than at any time over the last three decades, most likely due to extensive use of prescribed burning. 5. Synthesis and applications. In highly fire-prone landscapes, such as savannas, prescribed burning can be an effective means of: (i) bringing forward peak fire activity to the time of year when fire conditions are relatively mild and (ii) increasing abundance of long-unburnt vegetation. These changes are likely to favour persistence of a range of fire-sensitive communities. Our case study supports the strategic use of prescribed burning to protect fire-sensitive biota within highly fire-prone landscapes throughout the world.

1. 有观点担忧，澳大利亚北部卡卡杜国家公园（Kakadu National Park）内的阿纳姆高原（Arnhem Plateau）频发的高强度野火正在降低区域生物多样性。自20世纪80年代起，当地便推行旱季早期规定火烧（prescribed burning），旨在缩减旱季晚期野火的蔓延范围。2007年以来，当地进一步实施了更具战略性的规定火烧项目，以期延长灌丛地与雨林群落两次受火之间的间隔时长。
2. 本研究基于Landsat卫星获取的1980-2011年火灾历史数据，针对卡卡杜“石乡”（Stone Country）区域，评估规定火烧的实施效果，核心验证指标为其是否为优势植物群落达成了可容忍火灾间隔期（tolerable fire intervals）。
3. 分析结果显示，自20世纪80年代早期以来，区域火灾格局已大幅向有利于生物多样性的方向优化。尽管年度烧除总面积未发生显著变化，但长期来看火灾格局出现了两项关键转变：其一，火灾主导时段从旱季晚期转向旱季早期；其二，长期未过火植被的占比有所提升，这两项变化均有望对生物多样性产生积极效益。不过，由于2007年起推行的战略性规定火烧项目实施周期较短，验证其相关变化的统计学显著性存在一定局限，尽管该时段内长期未过火植被的占比确实呈现上升趋势。
4. 此前认为“阿纳姆高原的火灾格局正因频发的旱季晚期野火加剧生物多样性丧失”的观点是错误的；相较于过去三十年的任意时段，当前该区域的火灾状态已更为温和，这很大程度上得益于大范围规定火烧的应用。
5. 总结与应用启示：在稀树草原等火灾高发景观中，规定火烧可作为有效手段达成两大目标：其一，将火灾活动峰值提前至火灾条件相对温和的时段；其二，提升长期未过火植被的占比。这些变化有望助力多种火敏感群落（fire-sensitive communities）的存续。本案例研究证明，在全球范围内的火灾高发景观中，战略性推行规定火烧可有效保护火敏感生物群落。