Age-specific impacts of vegetation functional traits on gastrointestinal nematode parasite burdens in a large herbivore
Age-specific impacts of vegetation functional traits on gastrointestinal nematode parasite burdens in a large herbivore
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植被功能性状对大型食草动物胃肠道线虫寄生虫负担的年龄特异性影响
DOI：
10.1111/1365-2656.13978
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发表时间：
2023
影响因子：
4.8
通讯作者：
Wiersma E
中科院分区：
文献类型：
--
作者：
Wiersma E
胃肠道线虫(GIN)寄生虫在许多动物种群的生态动态中起着重要作用。最近的研究表明，GIN感染动态的细微尺度空间差异在野生动物系统中很重要，但这种差异背后的环境驱动因素仍然缺乏了解。我们使用了20多年来GIN寄生虫卵计数、宿主空间使用的数据以及圣基尔达Soay绵羊长期研究的空间植被数据，以测试空间自相关性和个体家庭范围内的植被如何预测三个年龄组的寄生虫负担。我们开发了一种新的方法来量化家庭范围内存在的植物功能特征，以描述现有植被的质量。植被和空间的影响因年龄段而异。在未成熟的羔羊中，寄生虫粪卵计数(FEC)在空间上是有结构的，在我们研究区域的北部和南部最高。与寄主体重和空间自相关性无关，植物功能性状可以预测寄生虫卵的数量。较高的卵数与更易消化和偏好的植物功能性状相关，这表明这种关联可能是由寄主密度和栖息地偏好驱动的。相反，我们在一岁幼羊或成年绵羊中没有发现寄生虫FEC与寄主家庭范围内的植物功能性状相关的证据。成体FEC在空间结构上是有结构的，在我们研究区域的东北部是最高的，而一岁的FEC没有表现出空间结构的证据。未成熟个体的寄生虫负担似乎更容易受到环境中细微尺度的空间差异的影响，这突显了这种异质性对于我们理解野生动物流行病学和健康的重要性。我们的发现支持了精细的环境变化对野生动物疾病生态学的重要性，并提供了新的证据，表明这种影响可能会因种群内的人口群体而异。
Gastrointestinal nematode (GIN) parasites play an important role in the ecological dynamics of many animal populations. Recent studies suggest that fine‐scale spatial variation in GIN infection dynamics is important in wildlife systems, but the environmental drivers underlying this variation remain poorly understood.We used data from over two decades of GIN parasite egg counts, host space use, and spatial vegetation data from a long‐term study of Soay sheep on St Kilda to test how spatial autocorrelation and vegetation in an individual's home range predict parasite burden across three age groups. We developed a novel approach to quantify the plant functional traits present in a home range to describe the quality of vegetation present.Effects of vegetation and space varied between age classes. In immature lambs, strongyle parasite faecal egg counts (FEC) were spatially structured, being highest in the north and south of our study area. Independent of host body weight and spatial autocorrelation, plant functional traits predicted parasite egg counts. Higher egg counts were associated with more digestible and preferred plant functional traits, suggesting the association could be driven by host density and habitat preference.In contrast, we found no evidence that parasite FEC were related to plant functional traits in the host home range in yearlings or adult sheep. Adult FEC were spatially structured, with highest burdens in the north‐east of our study area, while yearling FEC showed no evidence of spatial structuring.Parasite burdens in immature individuals appear more readily influenced by fine‐scale spatial variation in the environment, highlighting the importance of such heterogeneity for our understanding of wildlife epidemiology and health. Our findings support the importance of fine‐scale environmental variation for wildlife disease ecology and provides new evidence that such effects may vary across demographic groups within a population.