Abstract Deciduous shrubs are widely distributed throughout temperate and boreal conifer forests and influence a wide range of ecological processes and forest resources. In the interior western U.S., many deciduous shrubs are highly preferred forage by wild (elk, Cervus canadensis; deer, Odocoileus spp.) and domestic (cattle) ungulates which can influence shrub abundance, composition, structural characteristics, and related ecological processes and interactions. Stand disturbances and silvicultural practices can also affect shrub assemblages and managers in the interior western U.S. are increasingly implementing fuels reduction treatments such as stand thinning and prescribed fire to reduce fuel loads caused by more than a century of fire suppression. We evaluated the effects of ungulate herbivory and fuels reduction, alone and in concert, on deciduous shrub assemblages in coniferous dry forests of the interior west. We measured shrub richness, diversity, height, abundance and community composition in forest stands that underwent fuels reduction 15–17 years earlier, compared to untreated stands where no silvicultural treatments have occurred in over 50 years. Within each stand type, we also measured shrub assemblages in stands with and without ungulate herbivory. Shrub richness, diversity, frequency and height all declined in stands subjected to either fuels reduction treatments or herbivory; effects were most pronounced under the combined effect of fuels reduction and herbivory. Fuels reduction and herbivory also resulted in significant differences in shrub abundance and assemblage composition. Fuels reduction in dry forests with abundant ungulates may contribute to suppressed, more homogenous shrub communities. These effects may result in unintended impacts or alterations to important ecosystem processes and forest resources. Our results highlight the importance of considering responses of forest resources with low economic value, such as shrubs, in forest management activities.

中文翻译：

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燃料减少和大型食草动物对美国西部内陆干燥针叶林灌木组合的交互作用

摘要 落叶灌木广泛分布于温带和寒带针叶林中，对生态过程和森林资源产生广泛的影响。在美国西部内陆，许多落叶灌木是野生（麋鹿、加拿大鹿；鹿、Odocoileus spp.）和家养（牛）有蹄类动物的高度首选草料，它们会影响灌木的丰度、组成、结构特征以及相关的生态过程和相互作用. 林分干扰和造林做法也会影响灌木组合，美国西部内陆地区的管理人员越来越多地实施减少燃料的处理方法，例如林分间伐和规定的火灾，以减少一个多世纪以来的灭火造成的燃料负荷。我们单独和协同评估了有蹄类食草动物和燃料减少的影响，在内陆西部干燥针叶林中的落叶灌木丛上。我们测量了 15-17 年前减少燃料的林分的灌木丰富度、多样性、高度、丰度和群落组成，与 50 多年未进行造林处理的未处理林分相比。在每个林分类型中，我们还测量了有和没有有蹄类食草动物的林分中的灌木组合。在经过燃料减少处理或食草的林分中，灌木的丰富度、多样性、频率和高度都下降了；在燃料减少和食草的综合影响下，效果最为明显。燃料减少和食草也导致灌木丰度和组合组成的显着差异。在有丰富有蹄类动物的干燥森林中减少燃料可能有助于抑制，更同质的灌木群落。这些影响可能会对重要的生态系统过程和森林资源造成意外影响或改变。我们的结果强调了在森林管理活动中考虑低经济价值的森林资源（如灌木）响应的重要性。