National Park Service, Northeast Temperate Network, Bar Harbor, Maine, 04609, USA.
School of Biology and Ecology, Mitchell Center for Sustainability Solutions, University of Maine, Orono, Maine, 04469, USA.
Ecol Appl. 2021 Mar;31(2):e02239. doi: 10.1002/eap.2239. Epub 2020 Nov 15.
While invasive plant distributions are relatively well known in the eastern United States, temporal changes in species distributions and interactions among species have received little attention. Managers are therefore left to make management decisions without knowing which species pose the greatest threats based on their ability to spread, persist and outcompete other invasive species. To fill this gap, we used the U.S. National Park Service's Inventory and Monitoring Program data collected from over 1,400 permanent forest plots spanning 12 yr and covering 39 eastern national parks to analyze invasive plant trends. We analyzed trends in abundance at multiple scales, including plot frequency, quadrat frequency, and average quadrat cover. We examined trends overall, by functional group, and by species. We detected considerably more increasing than decreasing trends in invasive plant abundance. In fact, 80% of the parks in our study had at least one significant increasing trend in invasive abundance over time. Where detected, significant negative trends tended to be herbaceous or graminoid species. However, these declines were often countered by roughly equivalent increases in invasive shrubs over the same time period, and we only detected overall declines in invasive abundance in two parks in our study. Present in over 30% of plots and responsible for the steepest and greatest number of significant increases, Japanese stiltgrass (Microstegium vimineum) was the most aggressive invader in our study and is a high management priority. Invasive shrubs, especially Japanese barberry (Berberis thunbergii), Japanese honeysuckle (Lonicera japonica), multiflora rose (Rosa multiflora), and wineberry (Rubus phoenicolasius), also increased across multiple parks, and sometimes at the expense of Japanese stiltgrass. Given the added risks to human health from tick-borne diseases, invasive shrubs are a high management priority. While these findings provide critical information to managers for species prioritization, they also demonstrate the incredible management challenge that invasive plants pose in protected areas, particularly since we documented few overall declines in invasive abundance. As parks work to overcome deferred maintenance of infrastructure, our findings suggest that deferred management of natural resources, particularly invasive species, requires similar attention and long-term commitment to reverse these widespread increasing invasive trends.
虽然外来入侵植物在东美的分布情况相对较为明晰，但有关物种分布的时间变化以及物种间的相互作用却鲜少受到关注。因此，管理人员在进行管理决策时，并不知道哪些物种的威胁最大，因为他们不知道这些物种的传播能力、生存能力和与其他入侵物种竞争的能力。为了填补这一空白，我们利用美国国家公园管理局的监测计划数据，该数据来自于超过 1400 个永久性森林样地，这些样地横跨 12 年，覆盖了 39 个东部国家公园，以此分析入侵植物的趋势。我们分析了多个尺度上的丰度趋势，包括样地频率、样方频率和平均样方盖度。我们总体上、按功能组和物种分别分析了趋势。我们发现，入侵植物丰度的增加趋势明显多于减少趋势。事实上，我们研究的公园中，有 80%的公园在一定时间内入侵植物的丰度至少有一个显著增加的趋势。在检测到的地方，显著的负趋势往往是草本或禾本科物种。然而，在同一时期，入侵灌木的增加往往会抵消这些下降，而且在我们的研究中，只有两个公园的入侵植物丰度总体上呈下降趋势。在超过 30%的样地中都有出现，并且造成了最陡峭和最多的显著增加的日本千金子（Microstegium vimineum）是我们研究中最具侵略性的入侵物种，是一个高度需要管理的优先事项。入侵灌木，特别是日本小檗（Berberis thunbergii）、日本荚蒾（Lonicera japonica）、多花蔷薇（Rosa multiflora）和蓬蘽（Rubus phoenicolasius），也在多个公园中增加，有时甚至以日本千金子为代价。鉴于蜱传疾病对人类健康的额外风险，入侵灌木是一个高度需要管理的优先事项。虽然这些发现为管理人员提供了物种优先排序的关键信息，但它们也表明，入侵植物在保护区构成了巨大的管理挑战，特别是因为我们记录的入侵植物丰度总体下降很少。随着公园努力克服基础设施的延期维护，我们的研究结果表明，自然资源的延期管理，特别是入侵物种的管理，需要类似的关注和长期承诺，以扭转这些广泛的入侵趋势。
