Management Of Biological Invasions Research Articles

Biological Invasion Data Gaps in China: Examples of Distribution, Inventories, and Impact

The impact of invasive alien species (IAS) on nature and society is increasing globally. It is crucial to utilize information systems for evidence-based management, enabling the assessment and supporting survey and control actions. However, the lack of accessible and comprehensive baseline IAS data often impedes the ability to prioritize and allocate resources efficiently. Despite the increased public awareness of biological invasions in China over the past decades, the critical importance of data requirements has not been fully recognized, leading to gaps in available data. Here, we outline the key data demands for the management of biological invasions and highlight the current lack of high-quality data for invasion management in China, and critically assess data gaps in IAS distribution, inventory, and impact. Additionally, we propose a conceptual framework to illustrate the data requirements throughout the invasion management process, along with indicators to assess data quality within three dimensions: relevance, resolution, and reliability.

Thematic mapping of biosecurity highlights divergent conceptual foundations in human, animal, plant and ecosystem health

Effective biosecurity policies are essential to address several major sociological and environmental challenges facing humankind including existential pandemic risks, threats to food security, loss of ecosystem services and public resistance to pesticides and vaccines. Yet biosecurity is subject to multiple interpretations that include dealing with the threats from bioterrorism, managing laboratory biosafety to prevent the escape of pathogenic organisms, handling food and agricultural production systems to prevent disease introduction and addressing the threat of introduced organisms to flora, fauna and humans. The absence of a shared vision of what biosecurity encompasses means that decision-makers are often challenged to design appropriate biosecurity policies at national and global scales. The design of effective policy strategies requires an understanding of the methodological and conceptual barriers that constrain attempts to build an interdisciplinary approach to biosecurity. Here, the first thematic map of the biosecurity research landscape is undertaken to assess just how diverse the interpretation of biosecurity is amongst the global research community and the extent to which the articles published since 2000 represent a common conceptual foundation or are largely clustered within sectors. Co-citation, bibliographic coupling and co-word analyses highlighted that the field of biosecurity encompasses a wide range of domains from biochemistry through to political science, but the research supporting different sectors largely draws from a distinct literature base. While ecosystem and plant health were clustered together within the broad grouping of biological invasions, there was a clear separation from both human and animal health. Yet, there is considerable scope for the management of biological invasions to benefit from insights derived from social perspectives in human and animal health. Biosecurity remains divided by conceptual differences and specialised vocabularies that limit the effectiveness of biosecurity policies addressing biodiversity conservation, public health and food security. To overcome these constraints requires the building of a global biosecurity community that accepts a broader definition of biosecurity, avoids sectorial jargon and establishes mechanisms to cultivate interdisciplinarity through specialised collaborative centres, cross-sectorial research programmes and conceptually rich training programmes.

Real-time acoustic monitoring facilitates the proactive management of biological invasions

Real-time acoustic monitoring facilitates the proactive management of biological invasions

Mitigating invasive species using biochar derived from invasive plants in saline‐alkaline wetland plant communities dominated by Amaranthus palmeri

AbstractAimsEffective prevention and management of biological invasions are crucial. One promising approach involves introducing biochar to invaded plant communities to modify interspecific relationships among invasive and native plants, ultimately aiding in the suppression of invasive species. This study aimed to explore the effects of invasive‐plant biochar on an established invaded plant community.LocationTianjin coastal saline‐alkaline wetland, China (38°46′ N, 117°34′ E).MethodsInvaded plant communities were established using soils from an Amaranthus palmeri‐invaded wetland with an intact seed bank, incorporating invasive‐plant biochar derived from A. palmeri and Spartina alterniflora into the soil at 0%, 1%, 3%, and 5% addition rates (m/m). Plant above‐ground biomass, height, stem diameter, abundance, α/β‐diversity, niche breadth, and species co‐occurrence networks were analyzed.ResultsThe addition of invasive‐plant biochar significantly decreased the performance measures of the invaded plant community. The biochar addition rate had a more substantial impact on plant community structure than the type of biochar used. There was a decrease in the abundance of A. palmeri and an increase in native plants across most treatments, with S. alterniflora biochar exhibiting a more pronounced effect compared to A. palmeri biochar. Invasive‐plant biochar affected the niche breadth of A. palmeri and other dominant native species, particularly at higher addition rates, resulting in reduced niche overlap. At a 5% addition rate, A. palmeri and S. alterniflora biochar had contrasting effects on the complexity of interspecific relationships within the plant community. Phylogenetic β‐diversities were significantly correlated with the biochar addition rate and stochastic processes primarily governed plant community assembly across all treatments.ConclusionsOur findings underscore the potential of biochar derived from invasive plants to mitigate the impact of invasive species on saline‐alkaline wetland plant communities dominated by A. palmeri. This approach offers a promising avenue for managing biological invasions and restoring native plant species.

Intercontinental invasion dynamics of Cercopagis pengoi, an IUCN-listed planktonic invasive species

Predicting the spread of invasive species and understanding the role of niche dynamics in niche transferability are critical challenges in the management of biological invasions, both theoretically and practically. We used complementary species distribution modelling approaches, such as multivariate niche analysis and reciprocal distribution models, to test the niche conservatism hypothesis and to predict the potential distribution of the fishhook waterflea, Cercopagis pengoi. Our analysis indicated a significant similarity between its native and invasive ranges, suggesting that a subset of the Ponto-Caspian propagules may have been the founders of European populations. However, our results contradict the niche conservatism hypothesis, showing that C. pengoi has not fully occupied the available niche within its current invasive ranges. Moreover, we observed a notable niche expansion, reflecting a significant shift in niche following its intercontinental introduction in North America. Given the suitability of new environments for the expansion of C. pengoi and its tendency to evade detection prior to population surges, we recommend a focus on early detection through monitoring of both water columns and bottom sediments. This should be complemented by strict enforcement of ballast water regulations to curtail its spread in North America, Europe, and other suitable non-native regions globally.

A scenario‐guided strategy for the future management of biological invasions

Future dynamics of biological invasions are highly uncertain because they depend on multiple social–ecological drivers. We used a scenario‐based approach to explore potential management options for invasive species in Europe. During two workshops involving a multidisciplinary team of experts, we developed a management strategy arranged into 19 goals relating to policy, research, public awareness, and biosecurity. We conceived solutions for achieving these goals under different plausible future scenarios, and identified four interrelated recommendations around which any long‐term strategy for managing invasive species can be structured: (1) a European biosecurity regime, (2) a dedicated communication strategy, (3) data standardization and management tools, and (4) a monitoring and assessment system. Finally, we assessed the feasibility of the management strategy and found substantial differences among scenarios. Collectively, our results indicate that it is time for a new strategy for managing biological invasions in Europe, one that is based on a more integrative approach across socioeconomic sectors and countries.

Benefits do not balance costs of biological invasions

Abstract Biological invasions have profound impacts on biodiversity and ecosystem functioning and services, resulting in substantial economic and health costs estimated in the trillions of dollars. Preventing and managing biological invasions are vital for sustainable development, aligning with the goals of the United Nations Biodiversity Conference. However, some invasive species also offer occasional benefits, leading to divergent perceptions among stakeholders and sectors. Claims that invasion science overlooks positive contributions threaten to hinder proper impact assessment and undermine management. Quantitatively balancing benefits and costs is misleading, because they coexist without offsetting each other. Any benefits also come at a price, affecting communities and regions differently over time. An integrated approach considering both costs and benefits is necessary for understanding and effective management of biological invasions.

Rapid risk assessment of plant pathogenic bacteria and protists likely to threaten agriculture, biodiversity and forestry in Zambia

A prioritisation study was conducted to address the lack of adequate information about potential pests likely to be introduced in Zambia and become invasive. The study was conducted by subject matter experts from relevant institutions in and outside Zambia. Although this study focused on major pest categories, this paper only addresses bacteria and Protista. A list of 306 bacterial and 10 Protista species adjudged to affect plants was generated using CABI’s Horizon Scanning Tool. The 316 (total) pest species were refined to focus on pests that affect value chains important to Zambia’s economy. This resulted in a final list of 133 bacteria and eight Protista. Four additional bacteria species considered of phytosanitary interest were added and all 137 bacteria and eight Protista species were subjected to a rapid risk assessment using agreed guidelines. Vectors reported to transmit any of the pathogenic organisms were also subjected to a risk assessment. A proportion of 53% (n = 77 of 145) comprising 73 bacteria and four Protista species were reported as present in Africa. Of these, 42 (57%, n = 73) bacterial species and two (n=4) Protista species were reported in neighbouring countries. Considering a cut-off of 54, the highest scoring pests were 40 bacteria (highest score of 140) and three Protista (highest score of 125). Three actions were suggested for high-scoring pests, a detection surveillance, a pest-initiated pest risk analysis (PRA) or a detection surveillance followed by pest-initiated PRA. A “no action” was suggested where the risk was very low although, for some pathogenic organisms, a “no action” was followed by periodic monitoring. This information will contribute towards proactive prevention and management of biological invasions.

Considerations for developing and implementing a safe list for alien taxa.

Many species have been intentionally introduced to new regions for their benefits. Some of these alien species cause damage, others do not (or at least have not yet). There are several approaches to address this problem: prohibit taxa that will cause damage, try to limit damages while preserving benefits, or promote taxa that are safe. In the present article, we unpack the safe list approach, which we define as "a list of taxa alien to the region of interest that are considered of sufficiently low risk of invasion and impact that the taxa can be widely used without concerns of negative impacts." We discuss the potential use of safe lists in the management of biological invasions; disentangle aspects related to the purpose, development, implementation, and impact of safe lists; and provide guidance for those considering to develop and implement such lists.

Relatório temático sobre espécies exóticas invasoras no Brasil: sumário para tomadores de decisão

Abstract Biological invasions are one of the major threats to biodiversity and good quality of life, resulting from the translocation of species by human action. There are more than 500 alien species currently invading ecosystems in Brazil, particularly plants and fishes, while little is known about invasive microorganisms. Although invasive alien species are present in all ecosystems in the country, most have been recorded in habitats with greater human interference, such as urban and peri-urban areas, farmland, dams, reservoirs, ports, and canals. Historically, the southern and southeastern regions of Brazil have had more invasive alien species, but there has been an increase in the number of invasive alien species in the central-western and northern regions in recent decades. The ornamental trade of plants and fishes as well as the illegal pet trade of wild mammals and reptiles are some of the main pathways for invasive species introduction and spread in Brazil. Breeding and cultivation systems that allow escape to natural areas are a relevant route of species introductions in freshwater ecosystems, while unintentional introductions from shipping and infrastructure are of extreme concern in marine ecosystems. The negative impacts of invasive alien species on the biota mainly include changes in community structure and local decrease in native species richness, mediated by predation, competition, and ecosystem changes. Most negative impacts are recorded for intentionally introduced species, such as fishes and plants, but unintentional introductions have led to impacts on good quality of life, with associated costs and impacts on human health. The management of biological invasions faces challenges that need to be overcome, such as the lack of public knowledge about the impact of invasive alien species, the popular appeal of charismatic invasive species or those used by humans, and the use of controversial control techniques. However, successful experiences of eradication and control in terrestrial and marine ecosystems have been recorded, some of them involving public engagement in management actions. Recognizing the issue as a cross-cutting public policy and developing ongoing governance experiences are fundamental goals for the management of invasive alien species in Brazil.

Marine invasive alien species in Europe: 9 years after the IAS Regulation

Biological invasions, resulting from human activities, exert substantial impacts on ecosystems worldwide. This review focuses on marine invasive alien species (IAS) in Europe, examining the current state, proposing strategies to address the problem, and offering recommendations for enhanced management. Effective management of biological invasions relies on accessible, accurate data to inform decision-making. Information systems such as the European Alien Species Information Network (EASIN), Aquatic Non-Indigenous and Cryptogenic Species (AquaNIS), and World Register of Introduced Marine Species (WriMS) provide comprehensive databases on IAS, but their sustainability requires long-term maintenance, continuous updates, and support. Most countries lack specific monitoring programs for marine IAS, and standardization and improvement of monitoring methods are needed. Port monitoring plays a vital role in the early detection of new arrivals, and recent advancements in molecular techniques show promise for effective IAS monitoring. Risk screening tools are commonly employed to rank taxa based on their invasiveness potential in European regions, but variations in protocols can yield inconsistent results. European impact assessments highlight resource competition, novel habitat creation, and predation as primary mechanisms for negative impacts on biodiversity, while the creation of novel habitats represents a key mechanism for positive impacts. Preventing IAS introductions is critical, and measures such as ballast water treatment systems are implemented to reduce the likelihood of marine introductions. However, understanding introduction pathways remains uncertain for many IAS. Eradication and control efforts for marine IAS have limited success, emphasizing the need for enhanced biosecurity measures. Climate change, especially ocean warming, can intensify IAS impacts on native species and ecosystems. In climate change hotspots, some tropical aliens may, however, compensate for the loss of thermally sensitive natives with similar traits. Therefore, it is imperative to consider the interactions between climate change and IAS in developing effective management and conservation strategies. Enhancing IAS management in Europe entails i) securing adequate funding, ii) expanding the list of IAS of Union Concern to adequately cover marine invasions, iii) learning from countries with successful biosecurity practices, iv) sustaining information systems, v) improving monitoring and early warning systems with innovative technologies, vi) enhancing prediction models, vii) conducting integrated impact assessments and mapping cumulative IAS impacts, and vii) considering the potential benefits of IAS in ecosystem functioning and services.

Using Local Ecological Knowledge to Search for Non-Native Species in Natura 2000 Sites in the Central Mediterranean Sea: An Approach to Identify New Arrivals and Hotspot Areas.

The management of biological invasions is among the most urgent of global challenges and requires a significant monitoring effort to obtain the information needed to take the appropriate decisions. To complement standard monitoring, citizen science is increasingly being used. Within citizen science, the approach of collecting and investigating Local Ecological Knowledge (LEK) proved to be useful in the monitoring of non-native species. A LEK survey was carried out in 10 Sicilian and Maltese Natura 2000 sites in order to help in the early detection of non-native species. The survey was addressed to local fishers and SCUBA divers in order to investigate the occurrence of 24 selected marine non-native species and to identify potential hotspot areas of invasion through the use of six indicators: the occurrence of newly introduced nonindigenous species, the cumulative impacts of invasive alien species (CIMPAL) and the relative importance of species on the cumulative impacts (D1, D2, D3, and D4). The respondents confirmed the presence of 22 species since the year 2000 and reported 10 new ones registered in the investigated areas. The highest CIMPAL value was observed in two Sicilian Natura 2000 sites (ITA090028 and ITA040014) and the lowest on the western coast of Malta (MT0000101, MT0000102, MT0000103, and MT0000104) The four top-priority species according to indicators D1-D4 were Caulerpa cylindracea, C. taxifolia, Siganus luridus and S. rivulatus. The study produced a valid and useful scientific output to suggest and address management strategies to monitor the establishment of the non-native species.

Recent advances in availability and synthesis of the economic costs of biological invasions.

Biological invasions are a global challenge that has received insufficient attention. Recently available cost syntheses have provided policy- and decision makers with reliable and up-to-date information on the economic impacts of biological invasions, aiming to motivate effective management. The resultant InvaCost database is now publicly and freely accessible and enables rapid extraction of monetary cost information. This has facilitated knowledge sharing, developed a more integrated and multidisciplinary network of researchers, and forged multidisciplinary collaborations among diverse organizations and stakeholders. Over 50 scientific publications so far have used the database and have provided detailed assessments of invasion costs across geographic, taxonomic, and spatiotemporal scales. These studies have provided important information that can guide future policy and legislative decisions on the management of biological invasions while simultaneously attracting public and media attention. We provide an overview of the improved availability, reliability, standardization, and defragmentation of monetary costs; discuss how this has enhanced invasion science as a discipline; and outline directions for future development.

Strategies for the Biological Control of Parthenium hysterophorus L. in Eastern Pakistan

Abstract The arrival of the invasive agricultural weed parthenium, Parthenium hysterophorus , in Pakistan was first noted in the Gujrat district of the Punjab Province in 1980. The plant has now spread further in the Punjab Province as well as into Khyber Pakhtunkhwa (KP), the Islamabad Capital Territory (ICT) and Azad Jammu and Kashmir. The heartlands of parthenium infestation are in the central and northern districts of Punjab, the ICT and KP, and the weed is moving into the southern parts of Punjab and north-eastern KP. Given parthenium’s highly invasive nature, it is likely that it has already spread into the southern parts of Punjab, especially as the area is home to extensive irrigated farming, and it is possible that the plant has even reached Sind and Baluchistan provinces in the south and south-west of Pakistan. To date, two biological control agents for parthenium have reached Pakistan without being introduced deliberately, most likely arriving from India or Nepal: Zygogramma bicolorata – the Mexican or parthenium leaf beetle – and Puccinia abrupta partheniicola , or winter rust. This case study assesses the effectiveness of these existing biological control agents in Pakistan, the potential of redistribution projects to increase their impact and whether artificially inducing Z. bicolorata to emerge from diapause early could further stem parthenium growth in spring. The second part of the case describes the importation of the stem-boring weevil Listronotus setosipennis into a quarantine facility for host range testing. The plan is to boost Pakistan’s biological control programme by releasing the weevil in areas where parthenium occurs. Finally, the case also recommends additional biological control agents and strategies for the future. Adapted from: The biological control of Parthenium hysterophorus L. in Pakistan: Status quo and future prospects'. Management of Biological Invasions (2021), Volume 12, Issue 3: pages 509-526. This is an open access article distributed under terms of the Creative Commons Attribution License (Attribution 4.0 International - CC BY 4.0). Information © CAB International 2023

The Diversity of Alien Plant Species in South Africa’s National Botanical and Zoological Gardens

The management of biological invasions, which pose a growing threat to natural resources and human well-being, is critical for reducing associated negative impacts. As part of the process of developing a strategy for the management of biological invasions in the South African National Biodiversity Institute’s (SANBI) gardens, we collated a list of alien plant species from 13 gardens as part of a situational analysis. We requested lists of alien plant species recorded in each of the SANBI’s gardens. A total of 380 records included 225 alien plant species belonging to 73 families. A significant number of species were intentionally introduced through horticultural trade as ornamentals (49%; n = 225), while 20.9% were consumed as either food or medicine by humans. Plant life forms included woody and herbaceous plants, graminoids, succulents and ferns. Herbaceous (42.7%; n = 225) and woody plants (3.8%) were the dominant life forms. The Walter Sisulu National Botanical Garden had the highest number of alien species (88 species), followed by Kirstenbosch (61 species) and Pretoria (46 species) National Botanical Gardens, with herbaceous species constituting the largest number in all gardens (i.e., 47, 19, and 27 species, respectively). The number of species that we recorded that were listed in the National Environmental Management: Biodiversity Act (NEM: BA) (Act No. 10 of 2004): Alien and Invasive Species Regulations’ categories were not notably different from the number of unlisted species (58.2% vs. 42.8%). The number of species listed in the different categories varied significantly across the different gardens, with a significantly higher number of unlisted species and of Category 1b species in the Walter Sisulu, Kirstenbosch and Pretoria National Botanical Gardens than in other gardens. That a significantly larger number of alien species originated from South America points to the need to improve biosecurity controls on existing relations. The results of this study provided a baseline database to help comparison between successive surveys in future.

Citizen science can enhance strategies to detect and manage invasive forest pests and pathogens

Incorporating a citizen science approach into biological invasion management strategies can enhance biosecurity. Many citizen science projects exist to strengthen the management of forest pest and pathogen invasions within both pre- and post-border scenarios. Besides the value of citizen science initiatives for early detection and monitoring, they also contribute widely to raising awareness, informing decisions about eradication and containment efforts to minimize pest and pathogen spread, and even finding resistant plant material for restoration of landscapes degraded by disease. Overall, many projects actively engage citizens in the different stages of forest pest and pathogen invasions, but it is unclear how they work together across all stages of the entire biological invasion process to enhance biosecurity. Here we provide examples of citizen science projects for each stage of the biological invasion process, discuss options for developing a citizen science program to enhance biosecurity, and suggest approaches for integrating citizen science into biosecurity measures to help safeguard forest resources in the future.

Trophic interactions of an invasive gecko in an endemic-rich oceanic island: Insights using DNA metabarcoding

Understanding the trophic interactions of introduced predators is key for evidence-based management of biological invasions. This is particularly important in oceanic islands, where predator-prey networks often include numerous endemic and range-restricted species. Geckos are successful island colonizers and in recent years numerous species have established populations in a wide array of oceanic islands. One such species is the Moorish gecko (Tarentola mauritanica), which has colonized multiple islands across the Mediterranean basin, Caribbean and Macaronesia. The species was first reported in Madeira Island in 1993 and over the last 30 years has colonized most of the islands' southern coast and expanded to the nearby island of Porto Santo. Here, we used DNA metabarcoding to provide the first insights into the diet of this successful colonizer in its introduced range. The species' diet was mainly composed of ground-dwelling arthropods belonging to the families Porcellionidae (Isopoda), Julidae (Diplopoda) and Formicidae (Hymenoptera). The diet richness and composition were not affected by neither sex nor size of adult geckos, instead they both change across populations. However, trophic niche-width differed among size classes, with smaller geckos feeding on a wider range of prey. We identified over 160 different Operational Taxonomic Units in the diet of T. mauritanica, with 21.6% of them belonging to introduced invertebrates and 13.6% to native species. Native prey taxa included the endemic Madeira wall lizard (Teira dugesii), the sole native reptile to Madeira. We also detected several agricultural pests and disease vectors in the diet of this exotic predator, and 19 taxa identified as prey had not yet been recorded to Madeira. Of these, several are serious agricultural pests, highlighting how this introduced gecko can be used as a natural sampler, in particular for the early detection of invasive arthropod pests. This study emphasizes the importance of trophic studies for monitoring the impacts of introduced predators in fragile insular systems.

Eyes on the aliens: citizen science contributes to research, policy and management of biological invasions in Europe

Invasive alien species (IAS) are a key driver of global biodiversity loss. Reducing their spread and impact is a target of the Sustainable Development Goals (SDG target 15.8) and of the EU IAS Regulation 1143/2014. The use of citizen science offers various benefits to alien species’ decision-making and to society, since public participation in research and management boosts awareness, engagement and scientific literacy and can reduce conflict in IAS management. We report the results of a survey on alien species citizen science initiatives within the framework of the European Cooperation in Science and Technology (COST) Action Alien-CSI. We gathered metadata on 103 initiatives across 41 countries, excluding general biodiversity reporting portals, spanning from 2005 to 2020, offering the most comprehensive account of alien species citizen science initiatives on the continent to date. We retrieved information on project scope, policy relevance, engagement methods, data capture, data quality and data management, methods and technologies applied and performance indicators such as the number of records coming from projects, the numbers of participants and publications. The 103 initiatives were unevenly distributed geographically, with countries with a tradition of citizen science showing more active projects. The majority of projects were contributory and were run at a national scale, targeting the general public, alien plants and insects, and terrestrial ecosystems. These factors of project scope were consistent between geographic regions. Most projects focused on collecting species presence or abundance data, aiming to map presence and spread. As 75% of the initiatives specifically collected data on IAS of Union Concern, citizen science in Europe is of policy relevance. Despite this, only half of the projects indicated sustainable funding. Nearly all projects had validation in place to verify species identifications. Strikingly, only about one third of the projects shared their data with open data repositories such as the Global Biodiversity Information Facility or the European Alien Species Information Network. Moreover, many did not adhere to the principles of FAIR data management. Finally, certain factors of engagement, feedback and support, had significant impacts on project performance, with the provision of a map with sightings being especially beneficial. Based on this dataset, we offer suggestions to strengthen the network of IAS citizen science projects and to foster knowledge exchange among citizens, scientists, managers, policy-makers, local authorities, and other stakeholders.

Are lakes a public good or exclusive resource? Towards value-based management for aquatic invasive species

Invasive species are a prominent driver of global environmental change and management of biological invasions is a complex issue that requires attention to social and ecological contexts. Management efforts implemented without consideration of social dimensions have often been delayed or have failed due to community resistance. Despite this, much invasive species research has focused solely on the ecological dynamics of invasions. To advance our understanding of the social dimensions of efforts to confront invasive species, we analyze decision-making among stakeholders impacted by starry stonewort (Nitellopsis obtusa), a freshwater alga and key emerging invader in lakes in the upper midwestern US that, to our knowledge, has not been explored in the human dimensions of invasive species literature. Through a content analysis of 46 semi-structured interviews with stakeholders associated with lakes invaded by N. obtusa in Indiana, Wisconsin, and Minnesota, we assess stakeholders’ management preferences and the factors that shape both preferences and current practices. We examine current management strategies, perceptions of the importance of addressing starry stonewort, and stakeholder goals, as well as motivational and structural factors that shape and potentially limit decision-making. We highlight two “lake ethics” that emerge from our results where stakeholders see lakes as either a public good or an exclusive resource. We present a typology of these two distinct lake ethics and explore their implications for future efforts to manage N. obtusa, suggesting that managers should move towards value-based approaches that consider underlying community values tied to natural resources.

A centenary tale: population genetic insights into the introduction history of the oriental fire-bellied toad (Bombina orientalis) in Beijing

BackgroundThe successful establishment of a species population following a single introduction of a few individuals to a non-native area has been limited. Nevertheless, the oriental fire-bellied toad (Bombina orientalis) population in Beijing is purportedly descended from a single introduction of about 200 individuals translocated from Yantai, Shandong Province, China, in 1927.ResultsTo resolve the introduction process and to understand the genetic consequences since that introduction approximately 90 years ago, we investigated the population’s genetic diversity and structure using 261 toads from Beijing and two native Shandong populations and inferred the species’ introduction history using simulation-based approaches. Analysis of mitochondrial DNA (mtDNA) sequences showed the two haplotypes found in Beijing nested within Yantai haplotypes, thus corroborating the historical record of the translocation source. The mtDNA and 11 nuclear microsatellite markers revealed both considerably lower genetic diversity in Beijing than in the source population and strong genetic differentiation between them. Although the current census population in Beijing may be in the range of a few thousand, the effective population size was estimated at only 20–57. Simulations also suggest that this population may have descended from 40–60 founders.ConclusionsThe Beijing population’s genetic patterns were consistent with the consequences of a severe bottleneck during introduction followed by genetic drift. The introduction trajectory constructed for this B. orientalis population reveals the genetic footprints of a small population sustained in isolation for nearly a century. Our results provide an intriguing example of establishment success from limited founders and may inform ex situ conservation efforts as well as the management of biological invasions.