Abstract Monoculture plantations of fast-growing trees are increasing worldwide and, in many cases, these replace highly diverse natural environments. The Mesopotamian Savannas and the Ibera marshes ecoregions of northeastern Argentina are a mosaic of habitat types in which extensive areas of natural grasslands have been replaced by the planting of non-native pines (Pinus spp.). Their impact on the natural communities is unknown. We evaluated the effect of these plantations, the landscape configuration and the forestry management practices on the assemblages of medium to large-size terrestrial mammals of this region at landscape and stand levels. Camera-trap stations were deployed in three environments: 89 in natural grasslands, 54 in native forest patches, and 91 in tree plantations. At a landscape level, we evaluated the effect of the type of environment and of the extent of different land covers on mammal richness per station using GLM, and on species composition using one-way PERMANOVA and redundancy analysis. At a stand level, we assessed the effect of understory vegetation, and of the age and density of tree plantation stands, on the similarity in mammal species composition between tree plantations and native environments, using non-metric multidimensional scaling analyses and GLM. Species richness and species composition differed between native forests and other environments, but not between grasslands and plantations. The variations in composition between the environments differed among the two ecoregions: the species composition in the plantations was different from the grassland assemblage only in the Ibera marshes, which suggests that the impact of tree plantations depends on the local pool of species. Mammal assemblages were also affected by the proportion of forests and wetlands and the environmental heterogeneity in the landscape. The similarity between the mammal assemblages of pine plantations and those of native forests increased with the age of the stand and at intermediate tree densities. In this grassland-dominated but heterogeneous landscape, it seems that most medium and large grassland mammals do not perceive tree plantations as a barrier, regardless of their management. Actions at a stand level, such as planting at intermediate tree densities and promoting longer rotation times, are desirable to encourage the forest mammal assemblage to use the plantations. Forests and wetlands are acting as keystone habitats for many species that are clearly associated with the presence of these environments in the landscape. Keeping large areas of natural grasslands and wetlands sprinkled with forests is essential for the conservation of the mammal assemblages of this region.

中文翻译：

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人工林取代高生物多样性地区的天然草地：它们如何影响哺乳动物群落？

摘要 速生树木的单一栽培种植园在世界范围内不断增加，在许多情况下，它们取代了高度多样化的自然环境。阿根廷东北部的美索不达米亚热带稀树草原和伊贝拉沼泽生态区是栖息地类型的马赛克，其中大面积的天然草原已被种植非本地松树（Pinus spp.）所取代。它们对自然群落的影响是未知的。我们在景观和林分层面评估了这些人工林、景观配置和林业管理实践对该地区中大型陆生哺乳动物群落的影响。相机陷阱站部署在三种环境中：89 个在天然草原，54 个在原始森林斑块中，91 个在人工林中。在景观层面，我们使用 GLM 评估了环境类型和不同土地覆盖范围对每个站点的哺乳动物丰富度的影响，以及使用单向 PERMANOVA 和冗余分析对物种组成的影响。在林分层面，我们使用非度量多维尺度分析和 GLM 评估了林下植被、林木林分的年龄和密度对林木林和本地环境之间哺乳动物物种组成相似性的影响。原生林和其他环境之间的物种丰富度和物种组成不同，但草原和人工林之间没有。两个生态区的环境组成差异不同：种植园中的物种组成与仅在伊贝拉沼泽中的草原组合不同，这表明人工林的影响取决于当地的物种库。哺乳动物群落还受到森林和湿地比例以及景观环境异质性的影响。松树人工林的哺乳动物组合与原始森林的哺乳动物组合之间的相似性随着林分的年龄和中等树木密度而增加。在这个以草原为主但异质性的景观中，似乎大多数中大型草原哺乳动物并不将人工林视为障碍，无论它们的管理如何。林分层面的行动，例如以中等树木密度种植和促进更长的轮作时间，对于鼓励森林哺乳动物组合使用人工林是可取的。森林和湿地是许多物种的关键栖息地，这些物种显然与景观中这些环境的存在有关。保持大面积的天然草原和湿地散布着森林对于保护该地区的哺乳动物群落至关重要。