Abstract Context. The conservation of large wild herbivores presents a challenge posed by the fact that their broad habitat requirements overlap with various human activities. Elucidating the factors that explain their distribution patterns provides us with a better understanding of habitat–species relationships and facilitates the design of effective management policies. Aims. Identify the natural (forage availability, weather) and anthropogenic (hunting, interspecific competition) factors that explain the abundance and productivity distribution of the guanaco. Estimate guanaco abundance and productivity and describe their distribution. Methods. We estimated the abundance and productivity of guanaco by using aerial surveys during the breeding and non-breeding season of two consecutive years, following the strip-transect methodology; we then modelled these as a function of environmental factors by means of density surface models. Key results. The highest abundance and productivity of guanaco occurred mostly where mesic grassland was dominant. Guanaco abundance presented three hotspots on the basis of geographic location, and family groups were more productive at low to intermediate livestock level. Abundance was significantly higher in the breeding season for both years (5614 and 14 092 individuals) than in the non-breeding season (2922 and 6926 individuals), and it was higher in 2015 than in 2014. Productivity was higher in 2015 than in 2014 (0.54 and 0.46 calves per adult respectively). Conclusions. Guanaco responded to forage availability, occupying zones with low to intermediate food availability in the breeding season, and those with the highest availability in the non-breeding season. This could be due to interspecific competition between livestock and guanaco family groups. We propose that the overall guanaco response could also be explained by social structure or by unassessed factors such as predation risk by feral dogs. Implications. The guanaco could compensate for the use of habitats with a lower food availability during the breeding season by using better-quality habitats during the non-breeding season.

中文翻译：

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对丰度和生产力分布建模以了解栖息地-物种关系：原驼（Lama guanicoe）案例研究

摘要上下文。大型野生食草动物的保护提出了一个挑战，因为它们广泛的栖息地要求与各种人类活动重叠。阐明解释其分布模式的因素可以让我们更好地了解栖息地 - 物种关系，并有助于设计有效的管理政策。目标。确定解释原驼的丰度和生产力分布的自然（草料可用性、天气）和人为（狩猎、种间竞争）因素。估计原驼的丰度和生产力并描述它们的分布。方法。我们在连续两年的繁殖和非繁殖季节使用航测，按照带状样带法估算了原驼的丰度和生产力；然后我们通过密度表面模型将这些建模为环境因素的函数。关键结果。原驼的最高丰度和生产力主要出现在中等草原占主导地位的地方。根据地理位置，原驼丰度呈现出三个热点，家庭群体在中低牲畜水平上的生产力更高。两年度繁殖季节丰度（5614只和14092只）均显着高于非繁殖季节（2922只和6926只），2015年高于2014年。2015年生产力高于2014年（每个成年人分别有 0.54 和 0.46 头小牛）。结论。Guanaco 对饲料供应做出反应，在繁殖季节占据低到中等食物供应的区域，以及在非繁殖季节可用性最高的那些。这可能是由于牲畜和原驼家族群体之间的种间竞争。我们提出，整体原驼的反应也可以用社会结构或未经评估的因素来解释，例如野狗的捕食风险。影响。原驼可以通过在非繁殖季节使用质量更好的栖息地来补偿繁殖季节食物供应量较低的栖息地。