Abstract

Ecological niche models (ENMs) predict where species can occur in accordance with environmental factors. Suitability maps are generated through models to identify habitats more or less adapted to the species. Published works on the distribution and habitat use of Guiana dolphin, Sotalia guianensis, are limited to fine spatial scales. Here, we aimed to predict the potential geographical distribution of Guiana dolphins through ENMs and generate a map of suitable habitats for the species. Data were collected between 1997 and 2015 in Brazil, French Guiana, and Colombia. The environmental data were obtained from MARSPEC database with a cell resolution of 10 × 10 km. For modeling, 99 of the 859 initial occurrence points of the species were considered after rarefaction. Seven environmental variables were selected through factorial analysis: bathymetry, distance to shore, bathymetric slope, sea surface salinity (minimum monthly and annual range), and sea surface temperature (mean annual and annual range). Results from five distinct algorithms were assembled to generate the distribution model. Our findings show potential areas in shallow platforms of the continental margin of South and Central America, including regions where the species has never been reported, such as the Pacific Ocean, the Gulf of California, the Gulf of Mexico, and the oceanic islands in the Caribbean Sea. The absence of Guiana dolphins in these regions may be due to geographical (linking of North and South America), physical (water temperature), and biological (competition, limited ability to dispersal) limiting factors. The models suggest that the presence of other species of coastal dolphin may be an important limiting factor for the Guiana dolphin at both extremes of its distribution. The Guiana dolphin is habitat specialist with a clinal potential geographic distribution concentrated in tropical and subtropical shallow and coastal waters of the continental shelf of the western Atlantic Ocean. This more restricted distribution than reported by IUCN and other studies suggests a cautionary approach to its conservation status due to limited dispersal abilities and high overlap with human activities.

中文翻译：

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圭亚那海豚（Sotalia guianensis）的潜在分布：沿海河口和热带栖息地专家

摘要

生态位模型（ENM）会根据环境因素预测物种在何处发生。适应性地图是通过模型生成的，以识别或多或少适应该物种的栖息地。已发表关于瓜亚索马里圭亚那海豚的分布和栖息地利用的著作仅限于精细的空间尺度。在这里，我们旨在通过ENM预测圭亚那海豚的潜在地理分布，并生成适合该物种的栖息地的地图。在1997年至2015年之间收集了巴西，法属圭亚那和哥伦比亚的数据。环境数据是从MARSPEC数据库中获得的，其像元分辨率为10×10 km。为了进行建模，稀疏后考虑了该物种的859个初始出现点中的99个。通过因子分析选择了七个环境变量：测深法，到岸的距离，测深斜率，海面盐度（最小的月度和年度范围）和海面温度（平均的年度和年度范围）。组合了五个不同算法的结果以生成分布模型。我们的发现表明，在南美和中美洲大陆边缘的浅层平台中可能存在的区域，包括从未报告过该物种的区域，例如太平洋，加利福尼亚湾，墨西哥湾和太平洋中的海洋岛屿。加勒比海。这些地区缺少圭亚那海豚可能是由于地理因素（北美和南美的联系），物理因素（水温）和生物学因素（竞争，分散能力有限）所致。这些模型表明，在分布的两个极端情况下，沿海海豚的其他物种的存在可能是圭亚那海豚的重要限制因素。圭亚那海豚是栖息地专家，具有潜在的地理分布，主要分布在西大西洋大陆架的热带和亚热带浅海和沿海水域。这种分布比自然保护联盟和其他研究报告的限制更为严格，这表明由于其有限的传播能力和与人类活动的高度重叠，因此对其保存状态采取了谨慎的态度。