Department of Conservation Biology, University of Göttingen, Göttingen, Germany.
Conservation Biogeography Lab, Geography Department, Humboldt University, Berlin, Germany.
Glob Chang Biol. 2024 Jan;30(1):e17026. doi: 10.1111/gcb.17026. Epub 2023 Nov 14.
Many grassland ecosystems and their associated biodiversity depend on the interactions between fire and land-use, both of which are shaped by socioeconomic conditions. The Eurasian steppe biome, much of it situated in Kazakhstan, contains 10% of the world's remaining grasslands. The break-up of the Soviet Union in 1991, widespread land abandonment and massive declines in wild and domestic ungulates led to biomass accumulation over millions of hectares. This rapid fuel increase made the steppes a global fire hotspot, with major changes in vegetation structure. Yet, the response of steppe biodiversity to these changes remains unexplored. We utilized a unique bird abundance dataset covering the entire Kazakh steppe and semi-desert regions together with the MODIS burned area product. We modeled the response of bird species richness and abundance as a function of fire disturbance variables-fire extent, cumulative burned area, fire frequency-at varying grazing intensity. Bird species richness was impacted negatively by large fire extent, cumulative burned area, and high fire frequency in moderately grazed and ungrazed steppe. Similarly, overall bird abundance was impacted negatively by large fire extent, cumulative burned area and higher fire frequency in the moderately grazed steppe, ungrazed steppe, and ungrazed semi-deserts. At the species level, the effect of high fire disturbance was negative for more species than positive. There were considerable fire legacy effects, detectable for at least 8 years. We conclude that the increase in fire disturbance across the post-Soviet Eurasian steppe has led to strong declines in bird abundance and pronounced changes in community assembly. To gain back control over wildfires and prevent further biodiversity loss, restoration of wild herbivore populations and traditional domestic ungulate grazing systems seems much needed.
许多草原生态系统及其相关生物多样性依赖于火和土地利用之间的相互作用，这两者都受到社会经济条件的影响。欧亚草原生物群落，其中大部分位于哈萨克斯坦，拥有世界上剩余草原的 10%。1991 年苏联解体、广泛的土地废弃以及野生和家养有蹄类动物的大量减少导致了数百公顷土地上生物质的积累。这种快速增加的燃料使草原成为全球火灾热点，植被结构发生重大变化。然而，草原生物多样性对这些变化的反应仍未得到探索。我们利用了一个独特的鸟类丰富度数据集，涵盖了整个哈萨克草原和半沙漠地区，以及 MODIS 火烧面积产品。我们将鸟类物种丰富度和丰度的响应模型作为功能变量，包括火干扰变量-火范围、累积火烧面积、火频率，同时考虑了不同的放牧强度。在中度放牧和未放牧的草原中，大的火范围、累积火烧面积和高火频率对鸟类物种丰富度产生负面影响。同样，在中度放牧的草原、未放牧的草原和未放牧的半沙漠中，大的火范围、累积火烧面积和更高的火频率对鸟类的总体丰富度产生负面影响。在物种水平上，高火干扰的影响对更多的物种是负面的，而不是正面的。存在相当大的火灾遗留效应，至少可以检测到 8 年。我们的结论是，在后苏联的欧亚草原上，火干扰的增加导致了鸟类丰度的强烈下降，并导致群落组装发生明显变化。为了重新控制野火并防止进一步的生物多样性丧失，恢复野生食草动物种群和传统的家养有蹄类动物放牧系统似乎是非常必要的。
