Niche-based modelling as a tool for predicting the risk of alien plant invasions at a global scale

Predicting the probability of successful establishment of plant species by matching climatic variables has considerable potential for incorporation in early warning systems for the management of biological invasions. We select South Africa as a model source area of invasions worldwide because it is an important exporter of plant species to other parts of the world because of the huge international demand for indigenous flora from this biodiversity hotspot. We first mapped the five ecoregions that occur both in South Africa and other parts of the world, but the very coarse definition of the ecoregions led to unreliable results in terms of predicting invasible areas. We then determined the bioclimatic features of South Africa's major terrestrial biomes and projected the potential distribution of analogous areas throughout the world. This approach is much more powerful, but depends strongly on how particular biomes are defined in donor countries. Finally, we developed bioclimatic niche models for 96 plant taxa (species and subspecies) endemic to South Africa and invasive elsewhere, and projected these globally after successfully evaluating model projections specifically for three well‐known invasive species (Carpobrotus edulis, Senecio glastifolius, Vellereophyton dealbatum) in different target areas. Cumulative probabilities of climatic suitability show that high‐risk regions are spatially limited globally but that these closely match hotspots of plant biodiversity. These probabilities are significantly correlated with the number of recorded invasive species from South Africa in natural areas, emphasizing the pivotal role of climate in defining invasion potential. Accounting for potential transfer vectors (trade and tourism) significantly adds to the explanatory power of climate suitability as an index of invasibility. The close match that we found between the climatic component of the ecological habitat suitability and the current pattern of occurrence of South Africa alien species in other parts of the world is encouraging. If species' distribution data in the donor country are available, climatic niche modelling offers a powerful tool for efficient and unbiased first‐step screening. Given that eradication of an established invasive species is extremely difficult and expensive, areas identified as potential new sites should be monitored and quarantine measures should be adopted.     

Patterns of Biological Invasions in French Freshwater Systems by Non-Indigenous Macroinvertebrates

Freshwater biodiversity is threatened by several mechanisms, of which the introduction of non-indigenous species and habitat alteration are the two most important. Exotic species act at various levels of organisation of macroinvertebrate communities, and are involved in different processes mediating their impacts on biodiversity, such as habitat modification or negative interactions with autochthonous fauna. The present work gives a list of the 43 French freshwater non-indigenous species, which represent 1.2% of the French freshwater macroinvertebrates. We provide their geographic origins, their distributions among zoological units by comparison with the native fauna and their functional characteristics according to a recent typology based on bio/ecological traits. An exponential trend of the cumulated number of non-indigenous species was evidenced, with a clumping of invaders within crustaceans and molluscs. Donor areas of non-indigenous species are in majority European, and the Ponto-Caspian basin is identified as the principal one. This pattern could be explained by a spread along waterways but its origin lies in a process of recolonisation of defaunated areas following several episodes of glaciation/deglaciation in Western Europe during the last 80,000 years. Finally, from a functional point of view, non-indigenous species exhibit a limited diversity, with two functional groups representing 80% of them.     

近20年外来生物入侵危害与风险评估文献计量分析

外来生物入侵导致全球生物多样性下降,极大地威胁着生态系统健康,已造成很大的生态损失与经济损失。近年来,随着生物入侵的加剧,全球对生物入侵的研究力度不断加大。外来入侵生物的生态危害与风险评估可以为人们提供对入侵可能性和入侵方式更直接的信息,从而为管理者制定管理策略提供依据。基于最近20年间(1995—2014年)科学文献数据库Web of Science的科学引文索引数据库扩展版(SCI-E)中数据,对外来入侵生物的生态危害与风险评估方面的研究进行了文献计量分析,旨在了解当前国际研究现状,以便推动中国的生物入侵相关研究。为了全面掌握全球外来生物入侵生态危害与风险评估方面的研究,采用Bibexcel与TDA文献计量工具,对Web of Science数据库中相关文献进行了分析,去重后共获取5492篇文献。结果表明:近20年(1995—2014年)入侵生物的生态危害与风险评估方面的研究刊文量呈现前缓后剧增的趋势,2008—2014年进入了快速发展阶段,文献数量急剧增加,2014年达到最高(511篇);美国发文量远超其它国家,占据主导地位,中国刊文量排名第5。美国、澳大利亚、法国、英国、德国的研究论文影响力较大。刊文量最多的研究机构为美国农业部(USDA),中国科学院发文量排名第10位。研究学科主要为昆虫学、农艺学、植物科学、生态学,研究热点集中在生物防治、风险评估、粮食作物和经济作物的病虫害防治、杂草防控,以及生物入侵与气候变化的关系等方面。有关外来入侵生物的生态危害与风险评估的研究多集中于北美、澳大利亚和欧洲,未来要加强亚洲地区,特别是中国外来生物入侵风险评估的研究;要加强气候变化对外来生物物种特性的影响研究,更多关注入侵生物的生态控制与生态恢复方面的研究,以便更好地为今后长期有效地防控入侵生物提供理论与技术指导。     

致谢2013年度审稿专家

<正>2013年度,以下专家为《生物多样性》审阅稿件,在此向大家致以深切的谢意!正是有了各位专家认真、细致、及时地审阅稿件,才保障了刊物的学术质量,缩短了稿件的处理周期,从而帮助刊物赢得更多读者和作者的信赖。     

新西兰鸟类入侵成功的有关因素

了解外来入侵物种（alien invasive species,AIS)的生物学涉及纯生物学及应用生物学的问题,但是靠预先设计的实验来加深人们的了解显然是不可能的,然而我们可以研究现有的入侵,这也是一个很好的途径,本文利用新西兰历史上的一些记录,探讨了物种在新环境中成功定居的因素,令人惊奇的是,物种间的生物学差异对成功的定居几乎没有什么作用,相反,真正起作用的是一个物种被引入新环境的频率及数量。     

Andropogon gayanus (Gamba Grass) Invasion Increases Fire-mediated Nitrogen Losses in the Tropical Savannas of Northern Australia

Invasive alien grasses can substantially alter fuel loads and fire regimes which could have significant consequences for fire-mediated nutrient losses. The effects of the alien grass Andropogon gayanus Kunth. (Gamba grass) on fire-mediated nutrient losses was evaluated in Australia’s tropical savannas. Losses of macronutrients during fire were determined by comparing the nutrient pools contained in the fine fuel before fire and in the ash after fire. Pre-fire grass nutrient pools were significantly higher in A. gayanus plots than in native grass plots for all nutrients measured (N, P, K, S, Ca, and Mg). Nutrient losses were substantially higher in A. gayanus plots, with 113% higher losses for N, 80% for P, 56% for K, 63 for S, 355% for Ca, and 345% for Mg. However, only losses of N and Mg varied significantly between grass types. A simplified savanna ecosystem nutrient budget estimated that A. gayanus fires led to the net N loss of 20 kg ha⁻¹ y⁻¹. This is a conservative estimate because total fuel loads were relatively low (7.85 t ha⁻¹) for A. gayanus invaded plots leading to a relatively moderate intensity fire (6,408 kW m⁻¹). Higher A. gayanus fuel loads and fire intensities could potentially lead to losses of up to 61.5 kg N ha⁻¹ from the grass fuel. Over the long term, this is likely to lead to depletion of soil nutrients, particularly N, in the already low-fertility tropical savanna soils.