A plea for scale, and why it matters for invasive species management, biodiversity, and conservation

Invasive species are suspected to be major contributors to biodiversity declines worldwide. Counterintuitively, however, invasive species effects are likely scale-dependent, and are hypothesized to be positively related to biodiversity at large spatial scales. Past studies investigating the effect of invasion on biodiversity have been mostly conducted at small scales (<100 m2) that cannot represent large-dynamic landscapes by design. Therefore, replicated experimental evidence supporting a negative effect of invasive plants on biodiversity is lacking across many landscape types, including large grasslands. We collected data across eight large (333–809 ha) grassland landscapes managed with pyric herbivory—i.e., the recoupling of fire and grazing—to test how an invasive legume (Lespedeza cuneata) affected plant and bird communities at spatial grains ranging from 0.1 m2 to >3,000,000 m2. L. cuneata invasion effects on grassland plant diversity and composition changed with scale; be..., ,据推测，外来入侵物种（invasive species）是全球生物多样性衰退的主要诱因之一。然而与直觉相悖的是，外来入侵物种的影响很可能依赖于空间尺度，且有假说认为在大空间尺度下其与生物多样性呈正相关关系。以往针对生物入侵对生物多样性影响的研究，大多在小于100平方米的小尺度下开展，这类研究从设计上就无法代表大范围动态景观。因此，在包括大型草原在内的诸多景观类型中，仍缺乏可重复的实验证据以证明外来入侵植物对生物多样性的负面影响。 我们在8处采用火-放牧协同管理（pyric herbivory，即重新耦合火与放牧生态过程）的大型草原景观（面积333~809公顷）中收集数据，以探究入侵豆科植物截叶铁扫帚（Lespedeza cuneata）在0.1平方米至300万平方米以上的空间粒度下，对植物与鸟类群落的影响。 截叶铁扫帚入侵对草原植物多样性与群落组成的影响随空间尺度发生变化；be..., ,