Programa de Pós-graduação em Ecologia e Conservação, Instituto de Biociências, Fundação Universidade Federal de Mato Grosso do Sul, Brazil; Laboratório Ecologia da Intervenção, Instituto de Biociências, Fundação Universidade Federal de Mato Grosso do Sul, Brazil.
Programa de Pós-graduação em Biologia Vegetal, Universidade Federal de Minas Gerais, Brazil.
J Environ Manage. 2023 Jul 1;337:117665. doi: 10.1016/j.jenvman.2023.117665. Epub 2023 Mar 20.
The homogenization of fire regimes in a landscape may imply a temporal reduction in the availability of resources, such as flowers and fruits, which affect the fauna, as well as ecosystem services. We hypothesized that maintaining mosaic burning regimes, and thereby pyrodiversity, can diversify phenological patterns, ensuring year-round availability of flowers and fruits. Here we monitored open grassy tropical savanna phenology under different historical fire frequencies and fire seasons in a highly heterogeneous landscape in an Indigenous Territory in Brazil. We evaluated phenological patterns of tree and non-tree plants through monthly surveys over three years. These two life forms responded differently to climate and photoperiod variables and to fire. Different fire regimes led to a continuous availability of flowers and fruits, due to the complementarity between tree and non-tree phenologies. Late-season fires are supposed to be more devastating, but we did not detect a significant reduction in flower and fruit production, especially under moderate fire frequency. However, late burning in patches under high frequency resulted in a low availability of ripe fruits in trees. The fruiting of non-tree plants in patches under low fire frequency and early burning ensure ripe fruit, when there are practically no trees fruiting in the entire landscape. We conclude that maintaining a seasonal fire mosaic should be prioritized over historical fire regimes, which lead to homogenization. Fire management is best conducted between the end of the rainy season and the beginning of the dry season, when the risk of burning fertile plants is lower.
景观中火行为的同质化可能意味着资源可用性的时间减少，如花和果实，这会影响动物区系以及生态系统服务。我们假设维持镶嵌燃烧制度，从而维持火多样性，可以使物候模式多样化，确保全年都有花和果实。在这里，我们在巴西一个原住民领土的高度异质景观中，根据不同的历史火灾频率和火灾季节，监测开阔的热带稀树草原的物候。我们通过三年的每月调查评估了树木和非树木植物的物候模式。这两种生命形式对气候和光周期变量以及火的反应不同。不同的火灾制度导致花和果实的持续可用性，这是由于树木和非树木物候之间的互补性。晚季火灾应该更具破坏性，但我们没有发现花和果实产量明显减少，特别是在中度火灾频率下。然而，在高频率下的斑块中晚期燃烧导致树木中成熟果实的可用性降低。在低火灾频率和早期燃烧下的斑块中非树木植物的结实确保了成熟的果实，而在整个景观中实际上没有树木结实。我们得出的结论是，应该优先考虑维持季节性火镶嵌制度，而不是导致同质化的历史火制度。火灾管理最好在雨季结束和旱季开始之间进行，此时燃烧肥沃植物的风险较低。
