珠江口伶仃洋中华白海豚栖息地利用对海岸线等变迁的响应

沿岸鲸豚类栖息地易受人类活动的干扰，导致其分布和核心栖息地发生变化。珠江口-漠阳江口中华白海豚种群是目前所知全球范围内最大的种群，其中伶仃洋水域是其重要的栖息地。近年来，珠江口伶仃洋周边城市发展带来的人类活动增加，白海豚的生存压力日益增大，分析伶仃洋中华白海豚对栖息地环境变化的响应，研究对应的保护策略显得非常迫切。以多源陆地资源卫星Landsat为数据源，通过影像分析近43年珠江口伶仃洋围填海造成的海域流失，结合近20年来采用截线抽样法收集的海豚观测数据，运用含障碍核插值（Kernel interpolation with barriers）方法，分析白海豚的分布及核心栖息地的变化。结果显示：1986-2015年期间，研究区域内流失的海域面积为344.08km²；目击分布离人工海岸线的平均距离大于自然海岸线的平均距离，目击分布到自然海岸线和人工海岸线的平均距离均在减小，表明过去20年白海豚的栖息地使用选择发生了一些变化，被迫适应人类活动的干扰；1997-2016年白海豚的分布范围呈现先增加后减小，白海豚栖息地使用的重心偏向伶仃洋东部水域，核心栖息地趋向主航道和无人海岛附近水域萎缩，可能是海豚因海域食物资源减少而迫不得已的选择。不同时期，珠江口中华白海豚国家级自然保护区所覆盖的核心栖息地比例呈递减趋势，占比由79.9%下降到49.4%，当前有必要对保护区范围和功能区作出一些优化调整，以适应栖息地使用的变化格局。

Long-term changes in habitat use of Indo-Pacific humpback dolphins (Sousa chinensis) in response to anthropogenic coastline shift in Lingding Bay of Pearl River Estuary, China

Cetacean living coastal habitat often suffer from anthropogenic disturbance, which would change their original distribution and core habitat use. Pearl River Estuary-Moyang River Estuary (PRE-MRE) population is the largest known (putative) population of Indo-Pacific humpback dolphin in the world. Lingding Bay is a critical habitat of PRE-MRE population, where human activities have become frequently in recent years and dolphin survival pressure is increasing. Analysis the response of Indo-Pacific humpback dolphin to environment change and making corresponding conservation strategy are urgent. This research mainly discussed coastal waters loss process in the past 43 years from sea reclamation in the Lingding Bay using the multi-source Landsat imageries. To examine the change of distribution and core habitat of dolphins, a new kernel density estimation approach that accounted for physical barriers to movements was applied with sighting records from line-transect surveys during past 20 years. Our results showed that about 344.08 km² waters became unavailable from 1986 to 2015; average proximity of sighting sites to artificial shoreline was farther than to natural shoreline and average proximity of sighting sites to artificial shoreline and natural shoreline decreased, which indicated that dolphin habitat use changed and dolphin had to adapt anthropogenic disturbance; habitat use of dolphin focused on eastern Lingding Bay waters and distribution range reached peak in 2005-2006, but fell sharply in 2015-2016; dolphin''s core habitat approaching main channels and around undeveloped islands might be the only option result from resource depletion. The proportion of core habitat showed a decreasing trend in the Chinese White Dolphin National Nature Reserve of Guangdong Pearl River Estuary, which decreased from 79.9% to 49.4% in different period. We recommend that the government should adjust current protected range to fulfill the change pattern from habitat use.