Journal of Plant Ecology ›› 2023, Vol. 16 ›› Issue (4): 0-rtad002.DOI: 10.1093/jpe/rtad002

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草地植被调查中的观测者误差:物种多样性指标和物种丰度关系的影响

  

  • 收稿日期:2022-05-19 修回日期:2022-07-16 接受日期:2023-01-05 出版日期:2023-08-01 发布日期:2023-01-21

Observer error in grassland vegetation surveys: effects on species diversity metrics and species-abundance relationships

Lloyd W. Morrison1,2,*, Sherry A. Leis2, Michael D. DeBacker2   

  1. 1Department of Biology, Missouri State University, MO 65897, USA;
    2National Park Service, Heartland Inventory and Monitoring Program, Wilson's Creek National Battlefield, MO 65738, USA

摘要: 我们研究了观察者误差对4种常用物种多样性度量的影响:物种丰富度、香农-威纳多样性指数、香农-威纳均匀度指数和辛普森多样性指数。我们还评估了观察者误差如何影响由非度量多维尺度(NMS)排序确定的物种丰度关系的多变量分析得出的推论。3位不同的植物学家在美国密苏里州和堪萨斯州的两个国家公园对草原植被进行了采样。其中的两名植物学家对相同的地块进行了采样,编制了物种组成清单并估计了叶面覆盖率,然后比较了数据记录的差异。伪转换率(即由于观察者错误导致的表观转换率)在17.1%到22.1%之间,覆盖类别估计的差异在21.5%到30.5%之间。观察者对物种多样性测量值的百分比差异取决于数据的总结方式,但总是<20%,而且通常<10%。基于这些研究结果,与周转指数相比,物种多样性指标受观察者误差的影响相对较小。然而,周转指数包含更多信息,因为它们追踪的是单个物种,而在大多数物种多样性指数中,物种是可以互换的。因此,由于物种多样性指数的计算方式,识别出的错误较少。NMS排序显示,虽然不同观察者对某些地块的描述相似,但观察者对其他地块的记录之间的差异导致排序空间的分离更大。与另一个观察者相比,代表一个观察者记录的点通常在相同方向上在排序空间中移动。

关键词: 估计误差, 观察者误差, 伪周转率, 物种多样性度量, 排序, 植被调查

Abstract: We investigated the effect of observer error on four commonly used species diversity measures: species richness, Shannon-Weiner diversity, Shannon-Weiner evenness and Simpson's index of diversity. We also evaluated how observer error affects inferences derived from multivariate analyses of species-abundance relationships as determined by non-metric multidimensional scaling (NMS) ordination. Grassland vegetation was sampled by three different botanists at two national park units in Missouri and Kansas, USA. The same plots were sampled by two of the botanists, who compiled lists of species composition and estimated foliar cover. Differences in the data records were then compared. Pseudoturnover (i.e. apparent turnover due to observer error) ranged from 17.1% to 22.1%, and differences in cover class estimation ranged from 21.5% to 30.5%. The percentage difference in species diversity measures between pairs of observers depended on how data were summarized, but were always <20%, and often <10%. Based on these results, species diversity metrics are affected to a relatively smaller extent by observer error than turnover indices. Turnover indices, however, contain more information because they track individual species, whereas species are interchangeable in most species diversity indices. Thus, less of the error is identified because of how species diversity indices are calculated. NMS ordinations revealed that while the characterizations of some plots by different observers were similar, differences between observers' records for other plots resulted in greater separation in ordination space. Points representing one observer's records were often shifted in ordination space in the same direction compared with the other observer.

Key words: estimation error, observer error, pseudoturnover, species diversity metrics, ordination, vegetation surveys