Adalsteinsson Solny A, D'Amico Vincent, Shriver W Gregory, Brisson Dustin, Buler Jeffrey J
Department of Entomology and Wildlife Ecology, University of Delaware, Newark, Delaware 19716 USA.
United States Department of Agriculture Forest Service, Northern Research Station, Newark, Delaware 19716 USA.
Ecosphere. 2016 Mar;7(3). doi: 10.1002/ecs2.1317. Epub 2016 Mar 25.
Nonnative, invasive shrubs can affect human disease risk through direct and indirect effects on vector populations. Multiflora rose () is a common invader within eastern deciduous forests where tick-borne disease (e.g. Lyme disease) rates are high. We tested whether invasion affects blacklegged tick () abundance, and at what scale. We sampled host-seeking ticks at two spatial scales: fine-scale, within -invaded forest fragments; and patch scale, among -invaded and -free forest fragments. At a fine scale, we trapped 2.3 times more ticks under compared to paired traps 25 m away from . At the patch scale, we trapped 3.2 times as many ticks in -free forests compared to -invaded forests. Thus, ticks are concentrated beneath within invaded forests, but uninvaded forests support significantly more ticks. Among all covariates tested, leaf litter volume was the best predictor of tick abundance; at the patch scale, -invaded forests had less leaf litter than uninvaded forests. We suggest that leaf litter availability at the patch-scale plays a greater role in constraining tick abundance than the fine-scale, positive effect of invasive shrubs.
外来入侵灌木可通过对病媒种群的直接和间接影响来影响人类疾病风险。多花蔷薇（）是美国东部落叶林中常见的入侵物种，该地区蜱传疾病（如莱姆病）发病率很高。我们测试了多花蔷薇入侵是否会影响黑脚蜱（）的数量，以及影响的空间尺度。我们在两个空间尺度上对寻找宿主的蜱进行了采样：精细尺度，在多花蔷薇入侵的森林片段内；斑块尺度，在多花蔷薇入侵和未入侵的森林片段之间。在精细尺度上，与距离多花蔷薇25米远的配对诱捕器相比，我们在多花蔷薇下诱捕到的蜱多2.3倍。在斑块尺度上，与多花蔷薇入侵的森林相比，我们在未入侵的森林中诱捕到的蜱多3.2倍。因此，蜱集中在入侵森林中的多花蔷薇之下，但未入侵的森林中蜱的数量明显更多。在所有测试的协变量中，落叶体积是蜱数量的最佳预测指标；在斑块尺度上，多花蔷薇入侵的森林比未入侵的森林落叶更少。我们认为，斑块尺度上的落叶可用性在限制蜱数量方面比外来入侵灌木的精细尺度上的积极影响发挥着更大的作用。
