Same Invasion, Different Routes: Helminth Assemblages May Favor the Invasion Success of the House Mouse in Senegal

Previous field-based studies have evidenced patterns in gastrointestinal helminth (GIH) assemblages of rodent communities that are consistent with "enemy release" and "spill-back" hypotheses, suggesting a role of parasites in the ongoing invasion success of the exotic house mouse (Mus musculus domesticus) in Senegal (West Africa). However, these findings came from a single invasion route, thus preventing to ascertain that they did not result from stochastic and/or selective processes that could differ across invasion pathways. In the present study, we investigated the distribution of rodent communities and their GIH assemblages in three distinct zones of Northern Senegal, which corresponded to independent house mouse invasion fronts. Our findings first showed an unexpectedly rapid spread of the house mouse, which reached even remote areas where native species would have been expected to dominate the rodent communities. They also strengthened previous insights suggesting a role of helminths in the invasion success of the house mouse, such as: (i) low infestation rates of invading mice by the exotic nematode Aspiculuris tetraptera at invasion fronts except in a single zone where the establishment of the house mouse could be older than initially thought, which was consistent with the "enemy release" hypothesis; and (ii) higher infection rates by the local cestode Mathevotaenia symmetrica in native rodents with long co-existence history with invasive mice, bringing support to the "spill-back" hypothesis. Therefore, "enemy release" and "spill-back" mechanisms should be seriously considered when explaining the invasion success of the house mouse provided further experimental works demonstrate that involved GIHs affect rodent fitness or exert selective pressures. Next steps should also include evolutionary, immunological, and behavioral perspectives to fully capture the complexity, causes and consequences of GIH variations along these invasion routes

What are the economic costs of biological invasions? A complex topic requiring international and interdisciplinary expertise

Biological invasions can cause substantial economic losses and expenses for management, as well as harm biodiversity, ecosystem services and human well-being. A comprehensive assessment of the economic costs of invasions is a challenging but essential prerequisite for efficient and sustainable management of invasive alien species. Indeed, these costs were shown to be inherently heterogeneous and complex to determine, and substantial knowledge gaps prevent a full understanding of their nature and distribution. Hence, the development of a still-missing global, standard framework for assessing and deciphering invasion costs is essential to identify effective management approaches and optimise legislation. The recent advent of the InvaCost database – the first comprehensive and harmonised compilation of the economic costs associated with biological invasions worldwide – offers unique opportunities to investigate these complex and diverse costs at different scales. Insights provided by such a dataset are likely to be greatest when a diverse range of experience and expertise are combined. For this purpose, an international and multidisciplinary workshop was held from 12th to 15th November 2019 near Paris (France) to launch several project papers based on the data available in InvaCost. Here, we highlight how the innovative research arising from this workshop offers a major step forward in invasion science. We collectively identified five core research opportunities that InvaCost can help to address: (i) decipher how existing costs of invasions are actually distributed in human society; (ii) bridge taxonomic and geographic gaps identified in the costs currently estimated; (iii) harmonise terminology and reporting of costs through a consensual and interdisciplinary framework; (iv) develop innovative methodological approaches to deal with cost estimations and assessments; and (v) provide cost-based information and tools for applied management of invasions. Moreover, we attribute part of the success of the workshop to its consideration of diversity, equity and societal engagement, which increased research efficiency, creativity and productivity. This workshop provides a strong foundation for substantially advancing our knowledge of invasion impacts, fosters the establishment of a dynamic collaborative network on the topic of invasion economics, and highlights new key features for future scientific meetings.Fil: Diagne, Christophe. Universite Paris-Saclay;Fil: Catford, Jane A.. King's College London; Reino UnidoFil: Essl, Franz. Universidad de Viena; AustriaFil: Nuñez, Martin Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Courchamp, Franck. Universite Paris-Saclay

Are the “100 of the world’s worst” invasive species also the costliest?

Biological invasions are increasing worldwide, damaging ecosystems and socioeconomic sectors. Two decades ago, the “100 of the world’s worst” invasive alien species list was established by the IUCN to improve communications , identifying particularly damaging ‘flagship’ invaders globally (hereafter, worst). Whilst this list has bolstered invader awareness, whether worst species are especially economically damaging and how they compare to other invaders (hereafter, other) remain unknown. Here, we quantify invasion costs using the most comprehensive global database compiling them (InvaCost). We compare these costs between worst and other species against sectorial, taxonomic and regional descriptors, and examine temporal cost trends. Only 60 of the 100 worst species had invasion costs considered as highly reliable and actually observed estimates (median: US$43 million). On average, these costs were significantly higher than the 463 other invasive species recorded in InvaCost (median: US$ 0.53 million), although some other species had higher costs than most worst species. Damages to the environment from the worst species dominated, whereas other species largely impacted agriculture. Disproportionately highest worst species costs were incurred in North America, whilst costs were more evenly distributed for other species; animal invasions were always costliest. Proportional management expenditures were low for the other species, and surprisingly, over twice as low for the worst species. Temporally, costs increased more for the worst than other taxa; however, management spending has remained very low for both groups. Nonetheless, since 40 species had no robust and/or reported costs, the “true” cost of “some of the world’s worst” 100 invasive species still remains unknown

Economic costs of biological invasions in Ecuador:the importance of the Galapagos Islands

Biological invasions, as a result of human intervention through trade and mobility, are the second biggest cause of biodiversity loss. The impacts of invasive alien species (IAS) on the environment are well known, however, economic impacts are poorly estimated, especially in mega-diverse countries where both economic and ecological consequences of these effects can be catastrophic. Ecuador, one of the smallest mega-diverse countries, lacks a comprehensive description of the economic costs of IAS within its territory. Here, using "InvaCost", a public database that compiles all recorded monetary costs associated with IAS from English and Non-English sources, we investigated the economic costs of biological invasions. We found that between 1983 and 2017, the reported costs associated with biological invasions ranged between US$86.17 million (when considering only the most robust data) and US$626 million (when including all cost data) belonging to 37 species and 27 genera. Furthermore, 99% of the recorded cost entries were from the Galapagos Islands. From only robust data, the costliest identified taxonomic group was feral goats (Capra hircus; US$20 million), followed by Aedes mosquitoes (US$2.14 million) while organisms like plant species from the genus Rubus, a parasitic fly (Philornis downsi), black rats (Rattus rattus) and terrestrial gastropods (Achatina fulica) represented less than US2 million each. Costs of "mixed-taxa" (i.e. plants and animals) represented the highest (61% of total robust costs; US52.44 million). The most impacted activity sector was the national park authorities, which spent about US$84 million. Results from robust data also revealed that management expenditures were the major type of costs recorded in the Galapagos Islands; however, costs reported for medical losses related to Aedes mosquitoes causing dengue fever in mainland Ecuador would have ranked first if more detailed information had allowed us to categorize them as robust data. Over 70% of the IAS reported for Ecuador did not have reported costs. These results suggest that costs reported here are a massive underestimate of the actual economic toll of invasions in the country

Modelling the damage costs of invasive alien species

The rate of biological invasions is growing unprecedentedly, threatening ecological and socioeconomic systems worldwide. Quantitative understandings of invasion temporal trajectories are essential to discern current and future economic impacts of invaders, and then to inform future management strategies. Here, we examine the temporal trends of cumulative invasion costs by developing and testing a novel mathematical model with a population dynamical approach based on logistic growth. This model characterises temporal cost developments into four curve types (I–IV), each with distinct mathematical and qualitative properties, allowing for the parameterization of maximum cumulative costs, carrying capacities and growth rates. We test our model using damage cost data for eight genera (Rattus, Aedes, Canis, Oryctolagus, Sturnus, Ceratitis, Sus and Lymantria) extracted from the InvaCost database—which is the most up-to-date and comprehensive global compilation of economic cost estimates associated with invasive alien species. We find fundamental differences in the temporal dynamics of damage costs among genera, indicating they depend on invasion duration, species ecology and impacted sectors of economic activity. The fitted cost curves indicate a lack of broadscale support for saturation between invader density and impact, including for Canis, Oryctolagus and Lymantria, whereby costs continue to increase with no sign of saturation. For other taxa, predicted saturations may arise from data availability issues resulting from an underreporting of costs in many invaded regions. Overall, this population dynamical approach can produce cost trajectories for additional existing and emerging species, and can estimate the ecological parameters governing the linkage between population dynamics and cost dynamics

Global economic costs of herpetofauna invasions

Biological invasions by amphibian and reptile species (i.e. herpetofauna) are numerous and widespread, having caused severe impacts on ecosystems, the economy and human health. However, there remains no synthesised assessment of the economic costs of these invasions. Therefore, using the most comprehensive database on the economic costs of invasive alien species worldwide (InvaCost), we analyse the costs caused by invasive alien herpetofauna according to taxonomic, geographic, sectoral and temporal dimensions, as well as the types of these costs. The cost of invasive herpetofauna totaled at 17.0 billion US$between 1986 and 2020, divided split into 6.3 billion US$ for amphibians, 10.4 billion US$for reptiles and 334 million US$ for mixed classes. However, these costs were associated predominantly with only two species (brown tree snake Boiga irregularis and American bullfrog Lithobates catesbeianus), with 10.3 and 6.0 billion US$ in costs, respectively. Costs for the remaining 19 reported species were relatively minor ( 99%), while for reptiles, impacts were reported mostly through damages to mixed sectors (65%). Geographically, Oceania and Pacific Islands recorded 63% of total costs, followed by Europe (35%) and North America (2%). Cost reports have generally increased over time but peaked between 2011 and 2015 for amphibians and 2006 to 2010 for reptiles. A greater effort in studying the costs of invasive herpetofauna is necessary for a more complete understanding of invasion impacts of these species. We emphasise the need for greater control and prevention policies concerning the spread of current and future invasive herpetofauna.info:eu-repo/semantics/publishedVersio

Economic costs of invasive rodents worldwide : the tip of the iceberg

ACKNOWLEDGEMENTS We are extremely grateful to the organizers of the InvaCost workshop that allowed the genesis of this project, as well as to all contacted people who kindly answered to our requests for information about the costs of invasive rodents. We thank L. Nuninger and C. Assailly for their work in the initial project, and María Angulo and Nuria Cerdá for their help in generating the Fig. 3. Last, the authors thank Dr. Steffen Oppel and another anonymous reviewer for their thorough revision of the article which greatly improved it. Funding Information: This work was supported by the French National Research Agency (ANR-14-CE02-0021) and the BNP-Paribas Foundation Climate Initiative for funding the Invacost project which allowed the construction of the InvaCost database. This work was initiated following a workshop funded by the AXA Research Fund Chair of Invasion Biology. This research was also funded through the 2017-2018 Belmont Forum and BiodivERsA joint call for research proposals, under the BiodivScen ERA-Net COFUND programme. Funds for Elena Angulo and Liliana Ballesteros-Mejia came from the AXA Research Fund Chair of Invasion Biology of University Paris Saclay. Christophe Diagne was funded by the BiodivERsA-Belmont Forum Project ‘‘Alien Scenarios’’ (BMBF/PT DLR 01LC1807C). Ross N. Cuthbert received funding from the Leverhulme Trust (ECF-2021-001). Thomas W. Bodey received funding from the European Union’s Horizon 2020 research and innovation programme Marie Skłodowska-Curie fellowship (Grant No. 747120). Jean Fantle-Lepczyk received travel support to attend the Invacost workshop from Auburn University School of Forestry and Wildlife Sciences. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

The economic costs of biological invasions in Central and South America: a first regional assessment

Invasive alien species are responsible for a high economic impact on many sectors worldwide. Nevertheless, there is a scarcity of studies assessing these impacts in Central and South America. Investigating costs of invasions is important to motivate and guide policy responses by increasing stakeholders’ awareness and identifying action priorities. Here, we used the InvaCost database to investigate (i) the geographical pattern of biological invasion costs across the region; (ii) the monetary expenditure across taxa and impacted sectors; and (iii) the taxa responsible for more than 50% of the costs (hyper-costly taxa) per impacted sector and type of costs. The total of reliable and observed costs reported for biological invasions in Central and South America was USD 102.5 billion between 1975 and 2020, but about 90% of the total costs were reported for only three countries (Brazil, Argentina and Colombia). Costs per species were associated with geographical regions (i.e., South America, Central America and Islands) and with the area of the countries in km2. Most of the expenses were associated with damage costs (97.8%), whereas multiple sectors (77.4%), agriculture (15%) and public and social welfare (4.2%) were the most impacted sectors. Aedes spp. was the hyper-costly taxon for the terrestrial environment (costs of USD 25 billion) and water hyacinth (Eichhornia crassipes) was the hyper-costly taxon for the aquatic environment (USD 179.9 million). Six taxa were classified as hyper-costly for at least one impacted sector and two taxa for at least one type of cost. In conclusion, invasive alien species caused billions of dollars of economic burden in Central and South America, mainly in large countries of South America. Costs caused by invasive alien species were unevenly distributed across countries, impacted sectors, types of costs and taxa (hyper-costly taxa). These results suggest that impacted sectors should drive efforts to manage the species that are draining financial sources.info:eu-repo/semantics/publishedVersio

No Difference in the Incidence of Malaria in Human-Landing Mosquito Catch Collectors and Non-Collectors in a Senegalese Village with Endemic Malaria

International audienceBackground The human landing catches is the gold standard method used to study the vectors of malaria and to estimate their aggressiveness. However, this method has raised safety concerns due to a possible increased risk of malaria or other mosquito-borne diseases among the mosquito collectors. The aim of this study was to evaluate the incidence of malaria attacks among mosquito collectors and to compare these results with those of non-collectors in a Senegalese village. Methods From July 1990 to December 2011, a longitudinal malaria study involving mosquito collectors and non-collectors was performed in Dielmo village, Senegal. During the study period, 4 drugs were successively used to treat clinical malaria, and long-lasting insecticide-treated nets were offered to all villagers in July 2008. No malaria chemoprophylaxis was given to mosquito collectors. Incidence of uncomplicated clinical malaria and asymptomatic malaria infection were analyzed among these two groups while controlling for confounding factors associated with malaria risk in random effects negative binomial and logistic regression models, respectively. Results A total of 3,812 person-trimester observations of 199 adults at least 15 years of age were analyzed. Clinical malaria attacks accounted for 6.3% both in collectors and non-collectors, and asymptomatic malaria infections accounted for 21% and 20% in collectors and non-collectors, respectively. A non-significant lower risk of malaria was observed in the collector group in comparison with the non-collector group after adjusting for other risk factors of malaria and endemicity level (Clinical malaria: adjusted incidence rate ratio = 0.89; 95% confidence interval = 0.65-1.22; p= 0.47). Conclusion Being a mosquito collector in Dielmo was not significantly associated with an increased risk of malaria both under holoendemic, mesoendemic and hypoendemic conditions of malaria epidemiology. This result supports the view that HLC, the most accurate method for evaluating malaria transmission, may be used without health concerns in Dielmo

Managing biological invasions: the cost of inaction

Ecological and socioeconomic impacts from biological invasions are rapidly escalating worldwide. While effective management underpins impact mitigation, such actions are often delayed, insufficient or entirely absent. Presently, management delays emanate from a lack of monetary rationale to invest at early invasion stages, which precludes effective prevention and eradication. Here, we provide such rationale by developing a conceptual model to quantify the cost of inaction, i.e., the additional expenditure due to delayed management, under varying time delays and management efficiencies. Further, we apply the model to management and damage cost data from a relatively data-rich genus (Aedes mosquitoes). Our model demonstrates that rapid management interventions following invasion drastically minimise costs. We also identify key points in time that differentiate among scenarios of timely, delayed and severely delayed management intervention. Any management action during the severely delayed phase results in substantial losses (>50% of the potential maximum loss). For Aedes spp., we estimate that the existing management delay of 55 years led to an additional total cost of approximately $4.57 billion (14$ 32.31 billion, or more than seven times the observed inaction cost. These results highlight the need for more timely management of invasive alien species—either pre-invasion, or as soon as possible after detection—by demonstrating how early investments rapidly reduce long-term economic impacts