Most studies about the impact of urbanization on bird assemblages are from the Northern Hemisphere and most previous research has reported that cities reduced bird species richness and favored the settlement of exotic bird species. However, most of these studies took place in large cities and few of them were focused on riparian environments. The aim of our study was to investigate how richness and abundance of riparian birds change along the urban-rural gradient of Esquel, a small city in Patagonia. We established two rural riparian sites upstream, two urban riparian sites and two rural riparian sites downstream, and set up six point counts in each site. We counted birds twice (once in November 2013 and January 2014) and sampled vegetation coverage at each point count location. We used GLMMs to analyze data. Bird species richness decreased from rural to urban sites while bird abundance increased. Omnivores thrived in the city whereas insectivores and insectivore-frugivores were abundant in rural sites. Birds species richness was associated with plant species richness, while abundances of insectivores and insectivore-frugivores birds were related to shrub coverage and foliage height diversity. Our study highlighted that small cities can modify bird communities in the same way as large cities, thus policies for conservation of birds should be created to coincide with urbanizations. We recommend planting native species in all urban green spaces and informing citizens about the benefits of this action. If everybody collaborates, conservation of native birds in developing areas of Andean Patagonia will be possible.

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小城市会影响鸟类聚集吗？巴塔哥尼亚的评估

关于城市化对鸟类聚集的影响的大多数研究都来自北半球，并且以前的大多数研究都报告说，城市减少了鸟类的物种丰富度，并促进了外来鸟类的栖息。但是，这些研究大多数是在大城市进行的，很少针对河岸环境。我们研究的目的是调查河岸鸟类的丰富度和丰度如何沿巴塔哥尼亚的一个小城市埃斯奎尔的城乡梯度变化。我们在上游建立了两个农村河岸站点，在下游建立了两个城市河岸站点和两个农村河岸站点，并在每个站点中建立了六个点计数。我们对鸟类进行了两次计数（2013年11月和2014年1月一次），并在每个点计数位置采样了植被覆盖率。我们使用GLMM来分析数据。从农村到城市，鸟类的物种丰富度下降，而鸟类的丰度却增加了。杂食动物在城市繁盛，而农村地区的食虫和食肉食肉动物则很多。鸟类物种丰富度与植物物种丰富度相关，而食草动物和食草动物食肉类鸟类的丰富度与灌木覆盖率和叶片高度多样性有关。我们的研究强调，小城市可以像大城市一样修改鸟类群落，因此应该制定与城市化相适应的鸟类保护政策。我们建议在所有城市绿地中种植本地物种，并告知公民此举的好处。如果每个人都合作，将有可能在安第斯巴塔哥尼亚发展中地区保护本地鸟类。