Global Enhancers and Constraints of Alien Range Size in Mammals: The Roles of Species Attributes, Invasion History and Ecological Contexts

<b>Aim</b>: The rapid global expansion of alien invasion fronts is profoundly impacting native ecosystems. Understanding the enhancers and constraints behind the range size of alien species is crucial for mitigating biodiversity loss. While mammals are among the most well-studied taxa worldwide, their global invasion ecology remains under-investigated. In this study, we aimed to examine the potential relationships between their alien range size and species attributes, invasion history and environmental conditions.<br><b>Location</b>: Global.<b>Time period</b>: From prehistory to present.<br><b>Major taxa Studied</b>: Terrestrial mammals.<b>Methods</b>: We utilized the global Distribution of Alien Mammals database and linear mixed models to explore the relationships between alien range size and species attributes, introduction effort, residence time, human disturbance, native mammal richness, regional community composition, and climate conditions across zoogeographic realms.<br><b>Results</b>: Alien mammals may achieve larger range sizes when introduced to multiple distinct locations, have longer residence times, large native ranges, and high potential for fast population growth. Conversely, they face constraints when introduced to islands, exhibit specialized ecology, or encounter areas with high human disturbance. Climate emerged as a key factor, with temperature seasonality and climate match positively influencing alien range size. Contrary to our expectations, alien range size was positively correlated with native mammal richness, although it was constrained when placed within their native zoogeographic regions or realm, suggesting a zoogeography-dependent effect of biotic resistance.<b>Main Conclusions</b>: We elucidated how invasion history, environmental conditions, and species attributes influenced alien range size in mammals. Our findings showed that fast-growing generalists introduced to multiple locations within climates matching their native niche can achieve large alien ranges, even in natural environments with high native mammal richness. Management efforts should prioritize these species, particularly if originating from distant zoogeographic units with different communities, and use climate match to guide management actions and halt mammal invasion fronts across realms.

**研究目的**：全球外来入侵前沿的快速扩张正深刻扰动本土生态系统。厘清外来物种分布范围的驱动因子与限制条件，对减缓生物多样性丧失具有关键意义。尽管哺乳类是全球研究程度最高的类群之一，但其全球入侵生态学领域仍存在研究空白。本研究旨在探究外来哺乳类的分布范围大小与其物种属性、入侵历史及环境条件之间的潜在关联。
**研究范围**：全球。
**时间跨度**：从史前时期至当代。
**主要研究类群**：陆生哺乳类。
**研究方法**：本研究依托《全球外来哺乳类分布数据库（Global Distribution of Alien Mammals database）》，采用线性混合模型（linear mixed models），系统分析跨动物地理界（zoogeographic realm）范围内，外来哺乳类分布范围大小与物种属性、引入强度、定居时长、人类干扰强度、本土哺乳类物种丰富度、区域群落组成及气候条件之间的关联。
**研究结果**：当外来哺乳类被引入多个异质区域、拥有更长的定居时长、较大的本土分布范围以及较强的种群快速增长潜力时，其外来分布范围往往更为广阔。反之，若被引入岛屿生境、为生态特化类群，或遭遇高强度人类干扰区域，则其分布范围扩张将受到显著限制。气候因素为核心调控因子：温度季节性与气候匹配度可正向提升外来哺乳类的分布范围大小。与本研究初始预期相悖的是，外来哺乳类分布范围大小与本土哺乳类物种丰富度呈正相关，但当外来物种被置于其本土所属的动物地理界或区域时，该正相关关系会受到约束，这表明生物抵抗效应存在动物地理依赖性。
**主要结论**：本研究阐明了入侵历史、环境条件与物种属性如何共同影响哺乳类的外来分布范围大小。研究发现，生长速率快的广适性类群，若被引入多个气候条件与其本土生态位相匹配的区域，即便在本土哺乳类物种丰富度较高的自然环境中，也可形成大范围的外来分布区。入侵防控工作应优先针对此类物种，尤其是源自群落组成迥异的偏远动物地理单元的类群，并可借助气候匹配度指导防控策略，以遏制全球范围内的哺乳类入侵前沿扩张态势。