Urbanization is a major threat to wildlife with its cohort of environmental stressors. Urban remnant vegetation can help mitigate these impacts, but such remnants are subject to stressors that might be detrimental for some species. Habitat generalists have flexible diets and broader habitat tolerances that could favour their persistence in these remnants. Marmosets (Callithrix jacchus) and sloths (Bradypus variegatus) differ in their ecological and behavioural plasticity and both occur in urban areas. We predict marmosets to be less affected than sloths, a specialist species, by anthropogenic disturbance. We estimated their densities in urban forest fragments of semi-deciduous Atlantic forest in Paraiba, NE Brazil, with contrasting levels of urbanization. Using the distance sampling methodology, we surveyed 12 trails in a larger and less impacted fragment (515 ha) and 13 trails across nine smaller forest patches (2.1–8.0 ha) with a greater level of anthropogenic disturbance. Density of marmoset’s groups was higher in the area with lower anthropogenic disturbance, whereas sloths’ density was significantly higher in the more urbanized fragments. Marmosets seemed to be more impacted by noise than sloths. The density of both species in forest patches with higher level of anthropogenic disturbance was similar or even higher than densities from non-urban and less disturbed areas. Despite the negative impacts on wildlife, urbanization seems to cause a reduction of predators and an increase in availability of food resources that favour some species. Our results show the importance of small urban forest fragment for the persistence of marmosets and sloths in Neotropical cities.

中文翻译：

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大西洋森林碎片中的城市树懒和mar猴，具有不同的人为干扰水平

大量的环境压力因素使城市化成为对野生动植物的主要威胁。城市残余植被可以帮助减轻这些影响，但是这些残余物会承受可能对某些物种有害的压力源。人居综合主义者的饮食习惯灵活，生境耐受性更强，这可能有利于他们在这些残留物中的持久性。mos（Callithrix jacchus）和懒惰（Bradypus variegatus）的生态和行为可塑性不同，并且都发生在城市地区。我们预测，人为干扰对mar猴的影响比对专门物种树懒的影响要小。我们估算了巴西东北部帕拉伊巴的半落叶大西洋森林城市森林碎片中的密度，并得出了不同的城市化水平。使用距离采样方法，我们调查了较大且影响较小的碎片中的12条径迹（515公顷），以及横跨9条较小的人为干扰较大的森林斑块（2.1-8.0公顷）中的13条径迹。人为干扰较低的地区of猴的密度较高，而城市化程度较高的地区的树懒密度显着较高。mos猴似乎比树懒受到噪音的影响更大。人为干扰程度较高的森林斑块中两种物种的密度与非城市和受干扰程度较小的地区的密度相似甚至更高。尽管对野生动植物产生了不利影响，但城市化似乎导致掠食者的减少和对某些物种有利的粮食资源的增加。我们的研究结果表明，对于新热带城市中的小猿和树懒的持续存在而言，小城市森林碎片的重要性。