Data from: The importance of spinner dolphin (Stenella longirostris) resting habitat: implications for management

Linking key ecological characteristics with animal behaviour is essential for identifying and protecting important habitats that support life functions. Spinner dolphins display a predictable diurnal behavioural pattern where they forage offshore at night and return to sheltered bays during daytime to rest. These bays, which are also subject to considerable use by humans, have long been recognized as key habitats for this species although the extent to which dolphins rely on specific characteristics of these habitats for rest has not been quantified. An integration of boat-based and land-based group focal follow sampling regimes and three gradient boosting generalized additive models were developed to identify habitat features that contribute to the occurrence of resting spinner dolphins in coastal waters off Hawai'i Island. Two ‘in-bay’ models used data collected within bays, and a third ‘coastal’ model (near-shore, outside of bays) used data collected both inside and outside of bays. The coastal model identified that spinner dolphins were unlikely to rest outside sheltered bays. In-bay models showed that dolphins rested throughout daylight hours within bays with a peak resting period between 10.00 h to 14.00 h. The models also identified bottom-substrate-type as an important predictor of rest. Pseudo R2 values of 0·61 and 0·70 for the in-bay models and 0·66 for the coastal model showed that these models provided a good fit to the behavioural data for the occurrence of resting spinner dolphins. Synthesis and application. To date, studies evaluating spinner dolphin resting habitat have focussed on areas inside bays only. Here, we combined data collected inside and outside bays, and illustrate that should resting spinner dolphins be displaced from resting bays, they are unlikely to engage in resting behaviour elsewhere. Results provide further information on the importance of bays as important habitat for resting spinner dolphins. To mitigate the disturbance from human interactions during important rest periods, we recommend that management keep the spinner dolphin resting areas free from human activities. Our quantitative approach where models explicitly link behaviour with habitat characteristics is applicable to identify important habitats for protection of other taxa.

将关键生态特征与动物行为相关联，对于识别并保护支撑生命活动的重要栖息地至关重要。飞旋海豚（Spinner dolphin）展现出可预测的昼夜行为模式：夜间在近海觅食，日间返回受庇护的海湾休憩。这些同时受到人类大量活动影响的海湾，长期以来被视为该物种的关键栖息地，但海豚在休憩时对这些栖息地特定特征的依赖程度尚未得到量化。
本研究整合船基与陆基群体焦点跟随采样方案，构建了三类梯度提升广义加性模型（gradient boosting generalized additive models），以识别夏威夷岛近岸海域中与休憩飞旋海豚出现相关的栖息地特征。其中两类"海湾内"模型采用海湾内部采集的数据，第三类"近岸"模型（即海湾外的近岸区域）则同时使用海湾内外采集的数据。
近岸模型结果显示，飞旋海豚几乎不会在受庇护海湾之外的区域休憩。海湾内模型则表明，海豚日间在海湾内全程休憩，其中休憩高峰时段为10:00至14:00。上述模型同时识别出底质类型是影响休憩行为的重要预测因子。海湾内模型的伪决定系数（Pseudo R²）分别为0.61与0.70，近岸模型的伪决定系数为0.66，表明这些模型能够较好地拟合休憩飞旋海豚出现的行为数据。
研究综合与应用。截至目前，针对飞旋海豚休憩栖息地的评估研究仅聚焦于海湾内部区域。本研究整合了海湾内外的采集数据，并证实若休憩的飞旋海豚被迫离开其栖息海湾，它们几乎无法在其他区域开展休憩行为。本研究结果进一步佐证了海湾作为休憩飞旋海豚关键栖息地的重要性。为缓解人类活动在海豚重要休憩时段带来的干扰，我们建议管理部门应禁止人类活动进入飞旋海豚的休憩区域。本研究采用的定量方法可通过模型将行为与栖息地特征直接关联，该方法可用于识别其他生物分类群需予以保护的重要栖息地。