Background and aims

Woody plant encroachment poses a significant threat to grasslands globally, and in the southcentral USA, juniper (Juniperus virginiana) is rapidly taking over large areas of grasslands. Despite ongoing research, the reasons behind the rapid encroachment of juniper species in Oklahoma remain elusive. We hypothesized that the interaction between juniper canopy, aeolian, and wet-deposition processes lead to a modification in trace-element inputs through stemflow and throughfall. This, in turn, plays a crucial role in determining the success of juniper encroachment.

Methods

We measured the influx of trace-elements in stemflow and throughfall beneath juniper canopies of different sizes, contrasting the results with those obtained under ambient precipitation.

Results

Our research unveiled a significant influence of the juniper canopy on trace-element inputs via stemflow and throughfall. Specifically, there was a significant increase in manganese, boron, and chlorine inputs, coupled with a decrease in copper inputs. Additionally, there was an increase in most cations and sulfate.

Results

Our results indicate that juniper encroachment alters the profile of trace-element, cation, and anion inputs beneath their canopies. Increased levels of manganese and reduction of copper inputs into the ecosystem may enhance the juniper growth, creating a positive feedback mechanism that could contribute to the success of juniper and other woody encroachers.

中文翻译：

---

杜松（Juniperus virginiana）侵占草地导致微量元素输入增加

背景和目标

木本植物的侵占对全球草原构成了重大威胁，在美国中南部，杜松（Juniperus virginiana）正在迅速占领大片草原。尽管研究正在进行，但俄克拉荷马州杜松物种迅速入侵背后的原因仍然难以捉摸。我们假设杜松树冠、风积和湿沉积过程之间的相互作用导致通过茎流和径流的微量元素输入发生变化。反过来，这在决定杜松侵占的成功方面起着至关重要的作用。

方法

我们测量了不同大小的杜松树冠下茎流和径流中微量元素的流入量，并将结果与​​环境降水下获得的结果进行了对比。

结果

我们的研究揭示了杜松树冠通过茎流和径流对微量元素输入的显着影响。具体来说，锰、硼和氯的投入量显着增加，而铜的投入量则减少。此外，大多数阳离子和硫酸盐有所增加。

结果

我们的结果表明，杜松的侵占改变了其树冠下微量元素、阳离子和阴离子输入的分布。生态系统中锰含量的增加和铜的减少可能会促进杜松的生长，从而建立一个积极的反馈机制，有助于杜松和其他木本入侵植物的成功。