Figure - available from: Biological Invasions
This content is subject to copyright. Terms and conditions apply.
Source publication
We used a generalized linear model (GLM) to investigate environmental characteristics of capture sites of the invasive small Indian mongoose (Herpestes auropunctatus) on Amami Island, Japan. Data were collected from 2002 to 2011, from an area with the lowest mongoose density.
Data on capture levels and environmental factors were obtained within 1 ×...
Citations
... mote the spread of invasive alien plants (e.g. Follak et al., 2018; Joly et al., 2011; Lázaro-Lobo & Erwin, 2019) and animals (e.g.Brown et al., 2006;Komine et al., 2016;Recio et al., 2015). ...
Aim
Our current understanding of the causes of global extinction risk is mostly informed by the expert knowledge‐based “threats classification scheme” of the IUCN Red List of Threatened Species. Studies based on this dataset came to different conclusions about the relative importance of threats to species, depending on which taxonomic groups and levels of extinction risk were considered, and which version of the database was used. A key reason may lie in data limitations as causes of threat are well known for charismatic and well‐studied species, but not for the majority of species assessed. Here, we aim to fill current knowledge gaps about the importance of drivers of global extinction risks by focusing on endemic species.
Location
Global.
Methods
We examined country‐level variation in the proportion of globally threatened and extinct endemic species (Index of Threat, IoT) with a range of spatially explicit information about anthropogenic pressures, mitigation measures and data limitations.
Results
IoT coincided with several anthropogenic pressures, with substantial differences among kingdoms, life‐forms, levels of extinction risk and geographic locations. IoT of plants, particularly tropical woody plants of moderate extinction risk, was higher in countries with higher GDP and more invasive species. Furthermore, IoT of animals, particularly tropical mammals and invertebrates of moderate extinction risk, was higher in countries with higher GDP and smaller roadless areas.
Main conclusions
The extinction crisis for endemic species is associated with a complex network of potential drivers that need to be considered in concert in conservation policy and practice. Although our results require careful interpretation and remain sensitive to data limitations, we encourage similar studies at smaller scales to identify potential drivers of extinction risk at a higher resolution, particularly in regions where species assessments have been conducted consistently or on organisms with a uniform response time to pressures.
... Examples of agricultural damage include damage to agricultural products by common raccoons Procyon lotor (Suzuki and Ikeda 2019) and alien invasive insects (Kiritani 1998). In addition, the management of invasive alien species is conducted across the country, with several large-scale projects, such as an eradication project on islands (Kiritani 1998;Koyama et al. 2004;Fukasawa et al. 2013a;Watari et al. 2013;Komine et al. 2016;Sato 2019;Yagihashi et al. 2021). ...
Despite the large body of knowledge recognising the impact of biological invasions on biodiversity, their economic impact has been less evaluated. However, the associated economic costs ought to provide useful information on many different aspects to prevent and manage invasions. Here, we describe the economic costs of biological invasions in Japan using InvaCost, a recently-published global database on monetary costs extracted from English and non-English sources, as well as a complementary search, thereby filling a gap in regional knowledge. We focused on the following four dimensions when analysing the economic costs of biological invasions: damage to biodiversity, damage to human livelihood, management for biodiversity and management for human livelihood. Interestingly, there was no information about biological invasion costs for Japan in English, but the Japanese search and our additional survey provided a total of 630 cost entries, with a total economic cost of 728 million USD (2017 value, equivalent to 62 billion JPY). These entries appeared in 33 documents and corresponded to a total of 54 species. We showed that: 1) damage costs from biological invasions tend not to be assessed as frequently as management costs and are more underestimated; 2) despite the numerous entries, an overwhelmingly limited amount of the management budget was allocated to biodiversity conservation compared to protecting human livelihood; 3) budgets have been intensively invested in invasive species management on small islands, which reflects the vulnerability of small island ecosystems and economies to biological invasions; 4) the recorded costs still seem to be greatly underestimated, mainly due to the lack of recording (and potentially limited access to recorded cost information). These findings are not only specific to Japan, but may also be widely applicable to most other countries. The future recording of economic costs will help to close the gap between actual and recorded costs, leading to more realistic guidelines for tackling biological invasions.
... To enhance the mongoose capture rate and monitor mongoose presence, several sniffer dogs have been trained in mongoose detection, and other capturing and monitoring methods (e.g., camera traps, fur traps, chemical bait) have also been employed. The mongoose population size is now extremely low as a result of this major sustained eradication effort (Fukasawa et al. 2013a; Ministry of the Environment 2014; Komine et al. 2016) (Fig. 1), and the native fauna has recovered (Fukasawa et al. 2013b;Watari et al. 2013). Using a Bayesian state space model, Fukasawa et al. (2013a) estimated the population size of the mongoose to be 6141 (95% CI 5415-6817) in 2000 and 169 (95% CI 42-408) in 2011. ...
Invasive predators often decrease the abundance and distribution of native prey, but only a few studies have reported rapid predator-induced morphological and performance changes. An effective prey performance response may actually depend whether the predator uses a sit-and-wait or an active foraging strategy; the former would require prey to obtain the ability to move quickly in bursts, while the latter would require prey to increase their endurance to survive. The performance of native prey should therefore change according to the predation type of an invasive predator when it differs from that of native predators. As such, it is critical to evaluate prey performance to understand the effects of different predation types. We examined rapid morphological (hind limb length) and performance (burst movement ability, endurance) changes in a native prey frog induced by an invasive predator mongoose on Amami Island, Japan, where the only native predators of the frog are snakes. The hind limb length of the frog increased under the strong predation effect of the mongoose, which may have acted as a selective agent to induce rapid morphological responses. The endurance, but not the burst movement ability, of the frog was higher under the strong effect of predation by the mongoose. This suggests that endurance was a specific target of natural selection and that the performance of the native prey changed in response to the new predation type. Examining not only morphological but also performance changes will allow us to understand in detail the impact of invasive predators.
... Therefore, to conserve evolutionary processes on these two islands, both Amami and Tokunoshima Island populations should be conserved. Since 2000, the Ministry of the Environment has been trying to eradicate an invasive species of mongoose on Amami Island (Watari et al., 2008;Watari et al., 2013;Fukasawa et al., 2013;Komine et al., 2016). Recently, the Ministry of the Environment and local governments have taken initiatives to reduce feral cat populations on these islands. ...
... Therefore, to conserve evolutionary processes on these two islands, both Amami and Tokunoshima Island populations should be conserved. Since 2000, the Ministry of the Environment has been trying to eradicate an invasive species of mongoose on Amami Island (Watari et al., 2008;Watari et al., 2013;Fukasawa et al., 2013;Komine et al., 2016). Recently, the Ministry of the Environment and local governments have taken initiatives to reduce feral cat populations on these islands. ...
Character displacement is phenotypic divergence driven by competition (ecological character displacement) or reproductive interference (reproductive character displacement). Although previous studies have examined these phenomena separately, recent evidence suggests that reproductive interference can drive both reproductive and ecological character displacement, in that certain traits are related to both competition and reproduction. Thus, to evaluate the effect of competition, the effect of reproductive interference must be excluded. Here, we analysed ecological character displacement between non-congeneric frogs, which show little reproductive interference. Odorrana amamiensis inhabits the Amami and Tokunoshima Islands, Japan, whereas its non-congeneric competitor Babina subaspera inhabits the Amami Island. We tested three of the Schluter (2000) criteria for ecological character displacement: phenotypic changes in O. amamiensis between the two islands, phenotypic change related to prey preference, prey availability between the two islands. We demonstrated that the three criteria in Schluter (2000) were likely to be satisfied, indicating the occurrence of ecological character displacement in non-congeners without reproductive interference. Thus, we conclude that competition is potentially the main driver of this phenotypic divergence, and that non-congeners may be a suitable model for evaluating ecological character displacement in a variety of organisms, as the influence of reproductive interference can be excluded.
There is growing evidence that invasive species can be eradicated from small islands. This allows us to recognize that eradication as a realistic target for invasive species management. If the findings obtained from such projects form the basis for other projects, we may raise the overall level of invasive species management. In this review, I introduce an outline of mongoose eradication on Amami-Oshima Island, a project that has reached the final phase towards eradication, and I describe the findings obtained during the course of the project. Based on these findings, I have produced a generalized roadmap for invasive species management, divided into five phases. It is necessary that tactics should be updated in the course of any such project according to the varying population status. I have shown that it is important to establish a governance design that promotes breakthroughs to proceed to the next phases. In order to realize this, a collaborative system is needed involving government, researchers, and residents. Finally, I provide a practical checklist for invasive species management. The roadmap and checklist presented in this review offer guidelines for examining the concept and direction of various ongoing invasive species management projects.
