Patrón-Rivero Carlos, Osorio-Olvera Luis, Rojas-Soto Octavio, Chiappa-Carrara Xavier, Villalobos Fabricio, Bessesen Brooke, López-Reyes Kevin, Yañez-Arenas Carlos
Laboratorio de Ecología Geográfica, Unidad de Conservación de la Biodiversidad, UMDI-Sisal, Facultad de Ciencias, Universidad Nacional Autónoma de Mexico, Sierra Papacal, Yucatán, Mexico.
Laboratorio de Ecoinformática de la Biodiversidad, Departamento de Ecología de la Biodiversidad, Instituto de Ecología, Universidad Nacional Autónoma de México, Circuito Exterior s/n Anexo al Jardín Botánico, Ciudad Universitaria, Coyoacán, Ciudad de México, México.
PLoS One. 2024 Dec 5;19(12):e0310456. doi: 10.1371/journal.pone.0310456. eCollection 2024.
Understanding the factors affecting species distributions is a central topic in ecology and biogeography. However, most research on this topic has focused on species inhabiting terrestrial environments. At broad scales, abiotic variables consistently serve as primary determinants of species' distributions. In this study, we investigated the explanatory power of different abiotic variables in determining the distribution patterns of sea snakes on a global scale. Additionally, as the boundaries of realized thermal niches have significant implications for the ecology of species and their geographic distributions, we evaluated the asymmetry of realized thermal limits (i.e., differences in variances between the upper and lower limits of the realized thermal niche). We obtained 10 marine environmental variables from global databases along with >5000 occurrence records for 51 sea snake species in 4 genera across the group's entire known geographic range. Using these data, we employed correlative ecological niche modeling to analyze the influence of the individual variables in explaining species' distributions. To estimate the realized thermal limits of each species, we extracted the mean, minimum, and maximum temperature values at four depths (superficial, mean benthic, minimum benthic, and maximum benthic) for each occurrence record of the species. We then evaluated the asymmetry of the realized thermal niche by measuring and comparing the variances in the upper and lower limits. Both analyses (the importance of variables and realized thermal limit asymmetry) were performed at three taxonomic levels (sea snakes as a lineage of marine-adapted elapids [true sea snakes + sea kraits], subfamily, and genus) and two spatial resolutions. Overall, we found that temperature, silicate, nitrate, salinity, and phosphate concentrations were the most influential factors in explaining the spatial distribution patterns of sea snakes, regardless of taxonomic level or spatial resolution. Similarly, we observed that the realized thermal limits were asymmetric, with a higher variance in the lower limits, and that asymmetry decreased as the taxonomic level and spatial resolution increased.
了解影响物种分布的因素是生态学和生物地理学的核心主题。然而，关于这一主题的大多数研究都集中在栖息于陆地环境的物种上。在大尺度上，非生物变量一直是物种分布的主要决定因素。在本研究中，我们调查了不同非生物变量在全球范围内决定海蛇分布模式方面的解释力。此外，由于实际热生态位的边界对物种生态及其地理分布具有重要意义，我们评估了实际热极限的不对称性（即实际热生态位上限和下限之间的方差差异）。我们从全球数据库中获取了10个海洋环境变量，以及该类群整个已知地理范围内4个属51种海蛇的5000多条出现记录。利用这些数据，我们采用相关生态位建模来分析各个变量对解释物种分布的影响。为了估计每个物种的实际热极限，我们为该物种的每个出现记录提取了四个深度（表层、平均海底、最小海底和最大海底）的平均、最低和最高温度值。然后，我们通过测量和比较上限和下限的方差来评估实际热生态位的不对称性。这两项分析（变量的重要性和实际热极限不对称性）均在三个分类水平（作为适应海洋的眼镜蛇科一个谱系的海蛇[真海蛇+海蝰]、亚科和属）和两种空间分辨率下进行。总体而言，我们发现温度、硅酸盐、硝酸盐、盐度和磷酸盐浓度是解释海蛇空间分布模式的最有影响力的因素，无论分类水平或空间分辨率如何。同样，我们观察到实际热极限是不对称的，下限方差较高，并且随着分类水平和空间分辨率的提高，不对称性降低。
