Ramírez Francisco, Afán Isabel, Bouten Willem, Carrasco Josep Lluís, Forero Manuela González, Navarro Joan
Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals Facultat de Biologia Universitat de Barcelona Barcelona Spain.
Remote Sensing and GIS Laboratory (LAST-EBD) Estación Biológica de Doñana CSIC Seville Spain.
Ecol Evol. 2020 Apr 15;10(11):4716-4725. doi: 10.1002/ece3.6226. eCollection 2020 Jun.
Research focused on evaluating how human food subsidies influence the foraging ecology of scavenger species is scarce but essential for elucidating their role in shaping behavioral patterns, population dynamics, and potential impacts on ecosystems. We evaluate the potential role of humans in shaping the year-round distribution and habitat use of individuals from a typical scavenger species, the yellow-legged gull (), breeding at southwestern Spain. To do this, we combined long-term, nearly continuous GPS-tracking data with spatially explicit information on habitat types and distribution of human facilities, as proxied by satellite imagery of artificial night lights. Overall, individuals were mainly associated with freshwater habitats (mean proportion, 95% CI: 40.6%, 36.9%-44.4%) followed by the marine-related systems (40.3, 37.7%-42.8%), human-related habitats (13.5%, 13.2%-13.8%), and terrestrial systems (5.5%, 4.6%-6.5%). However, these relative contributions to the overall habitat usage largely changed throughout the annual cycle as a likely response to ecological/physiological constraints imposed by varying energy budgets and environmental constraints resulting from fluctuations in the availability of food resources. Moreover, the tight overlap between the year-round spatial distribution of gulls and that of human facilities suggested that the different resources individuals relied on were likely of anthropogenic origin. We therefore provide evidence supporting the high dependence of this species on human-related food resources throughout the annual cycle. Owing to the ability of individuals to disperse and reach transboundary areas of Spain, Portugal, or Morocco, international joint efforts aimed at restricting the availability of human food resources would be required to manage this overabundant species and the associated consequences for biodiversity conservation (e.g., competitive exclusion of co-occurring species) and human interests (e.g., airports or disease transmission).
关于评估人类食物补贴如何影响食腐动物觅食生态的研究很少，但对于阐明它们在塑造行为模式、种群动态以及对生态系统的潜在影响方面的作用至关重要。我们评估了人类在塑造西班牙西南部繁殖的典型食腐动物黄腿鸥个体的全年分布和栖息地利用方面的潜在作用。为此，我们将长期、近乎连续的GPS跟踪数据与关于栖息地类型和人类设施分布的空间明确信息相结合，以人造夜灯的卫星图像作为代理。总体而言，个体主要与淡水栖息地相关（平均比例，95%置信区间：40.6%，36.9%-44.4%），其次是与海洋相关的系统（40.3%，37.7%-42.8%）、与人类相关的栖息地（13.5%，13.2%-13.8%）和陆地系统（5.5%，4.6%-6.5%）。然而，这些对总体栖息地利用的相对贡献在全年周期中发生了很大变化，这可能是对不同能量预算施加的生态/生理限制以及食物资源可用性波动导致的环境限制的一种反应。此外，海鸥全年空间分布与人类设施分布的紧密重叠表明，个体所依赖的不同资源可能源于人为因素。因此，我们提供的证据支持了该物种在全年周期中对与人类相关的食物资源的高度依赖。由于个体有能力扩散并到达西班牙、葡萄牙或摩洛哥的跨界地区，因此需要国际联合努力来限制人类食物资源的可用性，以管理这种数量过多的物种及其对生物多样性保护（例如，竞争排斥共存物种）和人类利益（例如，机场或疾病传播）的相关影响。
