Universidade Estadual Paulista (Unesp), Instituto de Geociências e Ciências Exatas, Ecosystem Dynamics Observatory, Avenida 24-A 1515, 13506-900, Rio Claro, Brazil; Centre for African Ecology, School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, Private Bag X3, WITS, 2050, South Africa.
Universidade Estadual Paulista (Unesp), Instituto de Geociências e Ciências Exatas, Ecosystem Dynamics Observatory, Avenida 24-A 1515, 13506-900, Rio Claro, Brazil.
J Environ Manage. 2018 Jul 15;218:79-87. doi: 10.1016/j.jenvman.2018.04.004. Epub 2018 Apr 14.
Humans can alter fire dynamics in grassland systems by changing fire frequency, fire seasonality and fuel conditions. These changes have effects on vegetation structure and recovery, species composition, and ecosystem function. Understanding how human management can affect fire regimes is vital to detect potential changes in the resilience of plant communities, and to predict vegetation responses to human interventions. We evaluated the fire regimes of two recently protected areas in Madagascar (Ibity and Itremo NPA) and one in Brazil (Serra do Cipó NP) before and after livestock exclusion and fire suppression policies. We compare the pre- and post-management fire history in these areas and analyze differences in terms of total annual burned area, density of ignitions, burn scar size distribution, fire return period and seasonal fire distribution. More than 90% of total park areas were burned at least once during the studied period, for all parks. We observed a significant reduction in the number of ignitions for Ibity NPA and Serra do Cipó NP after livestock exclusion and active fire suppression, but no significant change in total burned area for each protected area. We also observed a seasonal shift in burning, with fires happening later in the fire season (October-November) after management intervention. However, the protected areas in Madagascar had shorter fire return intervals (3.23 and 1.82 years) than those in Brazil (7.91 years). Our results demonstrate that fire exclusion is unattainable, and probably unwarranted in tropical grassland conservation areas, but show how human intervention in fire and vegetation patterns can alter various aspects of the fire regimes. This information can help with formulating realistic and effective fire management policies in these valuable conservation areas.
人类可以通过改变火灾频率、火灾季节性和燃料条件来改变草原系统的火灾动态。这些变化会对植被结构和恢复、物种组成和生态系统功能产生影响。了解人类管理如何影响火灾制度对于检测植物群落的潜在变化以及预测植被对人类干预的反应至关重要。我们评估了马达加斯加的两个最近受保护地区（Ibity 和 Itremo NPA）和巴西的一个地区（Serra do Cipó NP）在牲畜排除和火灾抑制政策前后的火灾制度。我们比较了这些地区的管理前和管理后的火灾历史，并分析了总年燃烧面积、点火密度、烧伤疤痕大小分布、火灾返回期和季节性火灾分布方面的差异。在研究期间，超过 90%的公园总面积至少被燃烧过一次，所有公园都是如此。我们观察到 Ibity NPA 和 Serra do Cipó NP 在牲畜排除和积极的火灾抑制后，点火次数显著减少，但每个保护区的总燃烧面积没有显著变化。我们还观察到燃烧的季节性变化，在管理干预后，火灾发生在火灾季节（10 月至 11 月）的后期。然而，马达加斯加的保护区的火灾返回间隔（3.23 年和 1.82 年）比巴西的保护区（7.91 年）短。我们的研究结果表明，在热带草原保护地区，火灾排除是不可行的，而且可能是不必要的，但也表明了人类对火灾和植被模式的干预可以改变火灾制度的各个方面。这些信息可以帮助在这些宝贵的保护区制定现实和有效的火灾管理政策。
