Context

Trophic cascade theory predicts that predators indirectly benefit plants by limiting herbivore consumption. As humans have removed large predators from most terrestrial ecosystems the effect of their absence is unrecognized.

Objectives

A manipulation of dingo populations across Australia’s dingo-proof fence, within the Strzelecki Desert, was used to assess how predator absence has altered vegetation cover dynamics at landscape and site scales.

Methods

Landscape-scale analysis used Landsat fractional vegetation cover time series statistics to classify landforms and examine vegetation dynamics either side of the dingo fence. Generalised additive models were used to analyse the influence of predator absence on site-scale observations of fauna abundance and vegetation cover.

Results

The location of the dingo fence was visible as a change in both the standard deviation and maximum of non-photosynthetic vegetation (NPV) cover (e.g. wood and dry leaves) over 32 years (1988–2020). On average, NPV cover of swales decreased in the standard deviation by 1.4% and in the maximum by 5.0% where dingo abundance was reduced. The differences were consistent with suppressed vegetation growth following rainfall, due to high grazing pressure, where predators were rare. The landscape-scale analysis was supported by site-scale observations.

Conclusions

The influence of the trophic cascade was observable at both the landscape and site scales, suggesting that apex predator removal has significantly affected the arid ecosystem’s responses to resource pulses. Analogous effects may exist across the large areas of the planet over which apex predators have been extirpated.

中文翻译：

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营养级联的遥感：多时相Landat影像揭示了由去除顶点食肉动物驱动的植被变化

语境

营养级联理论预测，捕食者通过限制食草动物的消费而间接地使植物受益。由于人类已经从大多数陆地生态系统中移走了大型捕食者，因此人们认识不到它们的消失。

目标

在Strzelecki沙漠内，在澳大利亚防丁目栅栏上操纵丁狗种群的做法被用来评估捕食者的缺失如何改变景观和地点尺度上的植被覆盖动态。

方法

景观尺度分析使用Landsat分数植被覆盖时间序列统计数据对地貌进行分类，并检查丁格篱笆两侧的植被动态。使用广义的加性模型来分析捕食者的缺席对现场规模的动物丰度和植被覆盖率观测的影响。

结果

在32年（1988–2020年）内，丁哥篱笆的位置可以看出是标准偏差和非光合植被（NPV）覆盖物（例如木材和枯叶）最大值的变化。平均而言，当丁哥鱼丰度降低时，沼泽的NPV覆盖率的标准差降低了1.4％，最大降低了5.0％。这种差异与高放牧压力引起的降雨后植被生长受到抑制的现象一致，而掠食者很少。景观规模分析得到了现场规模观测的支持。

结论

营养级联的影响在景观和地点尺度上都是可以观察到的，这表明顶点掠食者的去除已显着影响干旱生态系统对资源脉冲的响应。类似的影响可能会在地球上已经消灭了顶点食肉动物的大片区域上存在。