Data from: Hide and seek in vegetation: time-to-detection is an efficient design for estimating detectability and occurrence

1. Ecology and conservation require reliable data on the occurrence of animals and plants. A major source of bias is imperfect detection, which, however, can be corrected for by estimation of detectability. In traditional occupancy models, this requires repeat or multi-observer surveys. Recently, time-to-detection models have been developed as a cost-effective alternative, which requires no repeat surveys and hence costs could be halved. 2. We compared the efficiency and reliability of time-to-detection and traditional occupancy models under varying survey effort. Two observers independently searched for 17 plant species in 44 100 m2 Swiss grassland quadrats and recorded the time-to-detection for each species, enabling detectability to be estimated with both time-to-detection and traditional occupancy models. In addition, we gauged the relative influence on detectability of species, observer, plant height and two measures of abundance (cover and frequency). 3.Estimates of detectability and occupancy under both models were very similar. Rare species were more likely to be overlooked; detectability was strongly affected by abundance. As a measure of abundance, frequency outperformed cover in its predictive power. The two observers differed significantly in their detection ability. 4. Time-to-detection models were as accurate as traditional occupancy models, but their data easier to obtain; thus they provide a cost-effective alternative to traditional occupancy models for detection-corrected estimation of occurrence.1. 生态学与保护研究亟需可靠的动植物发生数据。导致研究偏差的主要来源之一是不完全检测（imperfect detection），不过可通过检测率（detectability）估算对其进行校正。传统占用模型（occupancy models）需要开展重复调查或多观察者调查，而近期提出的检测时间模型（time-to-detection models）作为一种高性价比替代方案，无需重复调查，因此成本可降低一半。 2. 本研究在不同调查工作量条件下，对比了检测时间模型与传统占用模型的效率与可靠性。两名观察者在44个面积为100平方米的瑞士草原样方中独立搜寻17种植物，并记录每个物种的检测时间，从而可同时通过检测时间模型与传统占用模型估算检测率。此外，本研究还评估了物种、观察者、植株高度以及两种丰度度量指标——盖度（cover）与频度（frequency）——对检测率的相对影响。 3. 两种模型下的检测率与占用率估算结果高度一致。稀有物种更易被忽略；检测率受物种丰度的影响显著。作为丰度度量指标，频度的预测性能优于盖度。两名观察者的检测能力存在显著差异。 4. 检测时间模型的准确性与传统占用模型相当，但其数据采集更为便捷，因此在开展检测校正的发生量估算时，该模型可作为传统占用模型的高性价比替代方案。