Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, Oklahoma, USA.
Department of Ecosystem Science and Management, University of Wyoming, Laramie, Wyoming, USA.
Ecol Appl. 2023 Jan;33(1):e2712. doi: 10.1002/eap.2712. Epub 2022 Nov 20.
Habitat loss and changing climate have direct impacts on native species but can also interact with disease pathogens to influence wildlife communities. In the North American Great Plains, black-tailed prairie dogs (Cynomys ludovicianus) are a keystone species that create important grassland habitat for numerous species and serve as prey for predators, but lethal control driven by agricultural conflict has severely reduced their abundance. Novel disease dynamics caused by epizootic plague (Yersinia pestis) within prairie dog colonies have further reduced prairie dog abundances, in turn destabilizing associated wildlife communities. We capitalized on a natural experiment, collecting data on prairie dog distributions, vegetation structure, avian abundance, and mesocarnivore and ungulate occupancy before (2015-2017) and after (2018-2019) a plague event in northeastern Wyoming, USA. Plague decimated black-tailed prairie dog populations in what was then the largest extant colony complex, reducing colony cover in the focal area from more than 10,000 ha to less than 50 ha. We documented dramatic declines in mesocarnivore occupancy and raptor abundance post-plague, with probability of occupancy or abundance approaching zero in species that rely on prairie dogs for a high proportion of their diet (e.g., ferruginous hawk [Buteo regalis], American badger [Taxidea taxus], and swift fox [Vulpes velox]). Following the plague outbreak, abnormally high precipitation in 2018 hastened vegetation recovery from prairie dog disturbance on colonies in which constant herbivory had formerly maintained shortgrass structure necessary for certain colony-associates. As a result, we observed large shifts in avian communities on former prairie dog colonies, including near-disappearance of mountain plovers (Charadrius montanus) and increases in mid-grass associated songbirds (e.g., lark bunting [Calamospiza melanocorys]). Our research highlights how precipitation can interact with disease-induced loss of a keystone species to induce drastic and rapid shifts in wildlife communities. Although grassland taxa have co-evolved with high spatiotemporal variation, fragmentation of the remaining North American rangelands paired with higher-than-historical variability in climate and disease dynamics are likely to destabilize these systems in the future.
生境丧失和气候变化对本地物种有直接影响，但也会与疾病病原体相互作用，影响野生动物群落。在北美大平原，黑尾草原犬鼠（Cynomys ludovicianus）是一种关键物种，为许多物种创造了重要的草原栖息地，并作为捕食者的猎物，但由于农业冲突导致的致命控制，其数量已严重减少。草原犬鼠群中爆发的鼠疫（Yersinia pestis）引起的新型疾病动态进一步降低了草原犬鼠的数量，从而破坏了相关的野生动物群落。我们利用了一个自然实验，在美国怀俄明州东北部收集了草原犬鼠分布、植被结构、鸟类丰富度以及中型捕食者和有蹄类动物占有量的数据，这些数据在鼠疫发生之前（2015-2017 年）和之后（2018-2019 年）进行了收集。鼠疫使黑尾草原犬鼠的数量锐减，这是当时现存的最大的种群复合体，导致研究区域内的犬鼠种群从超过 10000 公顷减少到不到 50 公顷。我们记录到鼠疫后中型捕食者的占有量和猛禽数量急剧下降，一些物种对草原犬鼠的依赖程度很高，以至于它们的食物中有很大一部分来自草原犬鼠，这些物种的种群占有率或丰富度接近零，例如美洲隼（Buteo regalis）、美洲獾（Taxidea taxus）和红狐（Vulpes velox）。鼠疫爆发后，2018 年异常高的降水量加速了犬鼠干扰后的植被恢复，在这些犬鼠种群中，持续的食草作用维持了短草结构，这对某些与犬鼠有关的物种是必要的。因此，我们观察到前草原犬鼠种群的鸟类群落发生了巨大变化，包括山鹬（Charadrius montanus）几乎消失，与中草相关的鸣禽（如草地鹨[Calamospiza melanocorys]）增加。我们的研究强调了降水如何与疾病引起的关键物种丧失相互作用，导致野生动物群落发生剧烈和快速的变化。尽管草原生物已经与高时空变异性共同进化，但剩余的北美牧场的碎片化以及气候和疾病动态的历史上高于历史的变异性，可能会在未来使这些系统不稳定。
