Predicting the impact of invasive trees from different measures of abundance.
Predicting the impact of invasive trees from different measures of abundance.
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DOI：
10.1016/j.jenvman.2022.116480
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发表时间：
2022-10
影响因子：
8.7
通讯作者：
J. Moyano;Lucía B. Zamora-Nasca;P. Caplat;P. García Díaz;Bárbara Langdon;X. Lambin;L. Montti;Aníbal Pauchard;Martin A. Nuñez
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文献类型：
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作者：
J. Moyano;Lucía B. Zamora-Nasca;P. Caplat;P. García Díaz;Bárbara Langdon;X. Lambin;L. Montti;Aníbal Pauchard;Martin A. Nuñez
生物入侵在世界范围内产生负面影响，造成巨大的经济成本和生态影响。了解入侵物种丰度与其影响程度之间的关系（丰度-影响曲线）对于设计有效应对这些影响的预防和管理战略至关重要。然而，不同的丰度测量方法可能产生不同的丰度-影响曲线。木本植物是最具变革性的入侵者之一，特别是在草原生态系统中，因为引入了迄今为止尚不存在的生命形式。在这项研究中，我们的第一个目标是评估木本入侵者，扭叶松（以下简称松），对巴塔哥尼亚（阿根廷）的天然草地生产力和牲畜放牧的影响，建立丰度影响曲线。我们的第二个目标，是比较不同措施的松树丰富（密度，断面积和冠层覆盖）作为预测因子的松树对草地生产力的影响。我们的第三个目标是比较上述松树丰富度措施之间的丰富度-影响曲线，以及不同的影响措施：总草原生产力，适口生产力和绵羊放牧率（草原可持续支持的绵羊数量）。松树冠层覆盖，紧随其后的断面积，是最好的解释对草地生产力的影响的丰度的措施，但丰度的影响曲线的形状不同的丰度的措施。虽然松树密度和断面积的增加总是降低草地生产力，松树冠层覆盖率低于30%，草地生产力略有增加，更高的值导致指数下降。这种增加草地生产力与低水平的松树冠层覆盖可以解释为草原物种的压力非生物条件的改善。不同的影响措施，即总生产力，适口生产力和绵羊放养率，得出非常相似的结果。我们的丰度-影响曲线是指导入侵松树管理的关键，因为根据环境或经济影响阈值，正确评估有多少入侵个体（每个表面单位）是不可接受的，这对于确定何时开始管理行动至关重要。
Biological invasions produce negative impacts worldwide, causing massive economic costs and ecological impacts. Knowing the relationship between invasive species abundance and the magnitude of their impacts (abundance-impact curves) is critical to designing prevention and management strategies that effectively tackle these impacts. However, different measures of abundance may produce different abundance-impact curves. Woody plants are among the most transformative invaders, especially in grassland ecosystems because of the introduction of hitherto absent life forms. In this study, our first goal was to assess the impact of a woody invader,Pinus contorta(hereafter pine), on native grassland productivity and livestock grazing in Patagonia (Argentina), building abundance-impact curves. Our second goal, was to compare different measure of pine abundance (density, basal area and canopy cover) as predictors of pine's impact on grassland productivity. Our third goal, was to compare abundance-impact curves among the mentioned measures of pine abundance and among different measures of impact: total grassland productivity, palatable productivity and sheep stocking rate (the number of sheep that the grassland can sustainably support). Pine canopy cover, closely followed by basal area, was the measure of abundance that best explained the impact on grassland productivity, but the shape of abundance impact curves differed between measures of abundance. While increases in pine density and basal area always reduced grassland productivity, pine canopy cover below 30% slightly increased grassland productivity and higher values caused an exponential decline. This increase in grassland productivity with low levels of pine canopy cover could be explained by the amelioration of stressful abiotic conditions for grassland species. Different measures of impact, namely total productivity, palatable productivity and sheep stocking rate, drew very similar results. Our abundance-impact curves are key to guide the management of invasive pines because a proper assessment of how many invasive individuals (per surface unit) are unacceptable, according to environmental or economic impact thresholds, is fundamental to define when to start management actions.