Research Article |
Corresponding author: Yuya Watari ( ywatari@affrc.go.jp ) Academic editor: Emili García-Berthou
© 2021 Yuya Watari, Hirotaka Komine, Elena Angulo, Christophe Diagne, Liliana Ballesteros-Mejia, Franck Courchamp.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Watari Y, Komine H, Angulo E, Diagne C, Ballesteros-Mejia L, Courchamp F (2021) First synthesis of the economic costs of biological invasions in Japan. In: Zenni RD, McDermott S, García-Berthou E, Essl F (Eds) The economic costs of biological invasions around the world. NeoBiota 67: 79-101. https://doi.org/10.3897/neobiota.67.59186
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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.
日本における外来種の侵入が引き起こす経済的コストの初統合. 外来種の侵入が引き起こす生物多様性への影響については,多くの知見がある一方で,その経済的影響はあまり評価されていない.しかし,外来種の侵入が関連する経済的コストを評価することは,侵入の阻止,管理のための様々な側面から役立つ情報を提供してくれるはずである.ここでは,最近公開された英語情報源および英語以外の情報源から抽出した経済コストに関するグローバルなデータベースであるInvaCostを用いて,日本における外来種の侵入の経済的コストを記載するとともに,グローバルデータベースと地域的な知見のギャップを埋めるために,補完的な検索も行った.外来種の侵入の経済的コストを分析する際には,生物多様性への被害,人間の生活への被害,生物多様性のための管理,人間の生活のための管理の4つの次元に注目した.興味深いことに,日本の外来種の侵入のコストに関する情報は英語の情報源には存在しなかったが,日本語検索による情報源と本研究の追加調査により,合計630件のコスト情報件数が得られ,合計で7億2800万米ドル(2017年の価値,620億円相当)の経済コストが計上された.これらのエントリは33のデータソースに記載され,コストが記録された外来種は合計54種であった.本研究では以下のことを示した.1)外来種の侵入による被害コストは管理コストに比べて評価されることが少なく,過小評価される傾向があること,2)外来種管理の予算のうち,生物多様性の保全のための対策は多数の項目があるにもかかわらず,人間生活を守るための予算と比べると額が圧倒的に少ないこと,3)離島の外来種対策に集中的に予算が投入されており,これは離島の生態系や経済が外来種の侵入に脆弱であることを反映していること,4)コストは多くの場合記録されていなかったりアクセスが困難であったりするために,今回計上されたコストは依然として大幅に過小評価されているように思われること.これらの知見は日本だけでなく,他の多くの国にも広く適用可能である.今後,経済的コストを記録することで,実際のコストと計上されるコストのギャップを埋めることができ,外来種の侵入に対応するためのより現実的なガイドラインにつながると考えられる.
Première synthèse du coût économique des invasions biologiques au Japon. Malgré le vaste cortège de connaissances qui reconnaît l’impact des invasions biologiques sur la biodiversité, leur impact économique a été moins évalué. Pourtant, les coûts économiques associés sont sensés constituer des informations utiles pour bien des aspects de prévention et de gestion des invasions biologiques. Dans cette étude, nous décrivons le coût économique des bioinvasions au Japon en utilisant d’une part InvaCost, une base de données globale récemment publiée sur les coûts monétaires des invasions et extraites à partir de sources rédigées en langues anglaise et non-anglaises, et d’autre part des recherches complémentaires plus spécifiques, comblant ainsi des lacunes de connaissance régionale. Notre analyse des coûts économiques des invasions biologiques est déclinée selon les quatre dimensions suivantes : les dégâts sur la biodiversité, les dégâts sur les moyens humains de subsistance, la gestion de la biodiversité et la gestion des moyens humains de subsistance. De façon intéressante, il n’y a aucune information concernant le coût des invasions biologiques au Japon qui soit disponible en anglais, mais une recherche en Japonais et nos investigations complémentaires ont permis de compiler 630 mentions de coûts, pour un total de 728 millions USD (valeur de 2017, équivalents à 62 milliards yens). Ces mentions ont été identifiées à partir de 33 documents et correspondent à 54 espèces. Nous montrons que: 1) les coûts des dégâts liés aux invasions biologiques ont tendance à ne pas être évalués aussi fréquemment que les coûts liés à leur gestion, et sont davantage sous-estimés ; 2) malgré les nombreuses mentions, le budget alloué à la conservation de la biodiversité est étonnamment faible comparé à celui alloué pour préserver les moyens humains de subsistance ; 3) des budgets ont été massivement investis dans la gestion des espèces envahissantes sur les petites îles, ce qui reflète la vulnérabilité de ces écosystèmes et économies insulaires face aux invasions biologiques ; 4) les coûts mentionnés semblent largement sous-estimés, essentiellement à cause du manque de documentation rapportant ces coûts (et potentiellement d’un accès limité aux informations sur les coûts rapportés). Ces résultats ne sont pas spécifiques au Japon, mais pourraient aussi être largement applicables à la plupart des autres pays. De futurs efforts sur l'estimation et la documentation des coûts économiques permettra de combler l’écart entre les coûts réels et les coûts effectivement enregistrés, ce qui mènera à des recommandations plus réalistes pour lutter contre les invasions biologiques.
Primera síntesis de los costos económicos de las invasiones biológicas en Japón. A pesar de la gran cantidad de información científica sobre las invasiones biológicas que reconoce los impactos en la biodiversidad, los impactos económicos han sido menos evaluados. Sin embargo, los costos económicos asociados a las invasiones deberían proporcionar información útil en muchos aspectos, para prevenir y gestionar las invasiones. En este trabajo, describimos los costos económicos de las invasiones biológicas en Japón, usando la recientemente publicada base de datos InvaCost, que contiene los costes económicos extraídos a partir de documentos en lengua inglesa y en otras lenguas no inglesas, así como datos obtenidos en una búsqueda complementaria, lo cual ha llenado una laguna del conocimiento regional. Enfocamos el análisis de los costos económicos de las invasiones biológicas en las siguientes cuatro dimensiones: los daños a la biodiversidad, los daños al bienestar humano, la gestión para la biodiversidad y la gestión para el bienestar humano. Es de destacar que no hubo información en inglés para Japón, mientras que nuestra búsqueda adicional resultó en 630 entradas de costos, con un total económico de 728 millones de dólares americanos (valor de 2017, equivalente a 62 mil millones de yenes). Estas entradas de costos procedieron de 33 documentos y correspondieron a un total de 54 especies. Mostramos que: 1) los daños de las invasiones biológicas parecen no haber sido evaluados tan frecuentemente como las estrategias de gestión y por lo tanto parecen más subestimados; 2) a pesar de las numerosas entradas, la cantidad de dinero de gestión asignada a biodiversidad fue abrumadoramente limitada en comparación con la asignada al bienestar humano; 3) el dinero se ha invertido de forma intensiva en el manejo de las especies invasoras en islas pequeñas, lo que refleja la vulnerabilidad de los ecosistemas de las islas pequeñas y sus economías a las invasiones biológicas; 4) los costos reportados parecen estar aún fuertemente subestimados, debido sobre todo a la falta de registros (y por un acceso a la información sobre costos potencialmente limitado). Estos resultados no son específicos de Japón, sino que pueden ser aplicados ampliamente a la mayor parte de los países. Si en el futuro se registran los costes económicos, esto ayudará a cerrar la brecha que existe entre los costes que ocurren y los reportados, lo cual llevará a proponer medidas más realistas para abordar las invasiones biológicas.
Actual costs, biodiversity, island, InvaCost, invasive species, Japanese, non-English language, underestimated costs
Biological invasions are known to be a leading cause of biodiversity degradation worldwide (
Japan has the third largest GDP (
Japan features more than 6,800 islands (
Map of the four main islands (mainland: Hokkaido, Honshu, Shikoku, Kyushu) and Nansei Islands and Ogasawara Islands in Japan.
A recently-published database of the economic costs of biological invasions (
To analyse the economic cost of biological invasions in Japan, we used InvaCost (version 3.0, openly available at https://doi.org/10.6084/m9.figshare.12668570), a recently-compiled database which compiles the monetary impacts of invasive species reported in English and non-English documents worldwide (
Given the importance of the search in Japanese, we summarise here how this search was performed (for more details, see
A total of 329 cost entries was obtained from InvaCost_v3.0. Only one source came from the English database; the remaining 328 entries were Japanese and came from the non-English database (Suppl. material
We also conducted additional surveys to avoid the omission of cost data from important invasive alien species in Japan, because the searches conducted in English and non-English emphasised the uniformity of the search methods across countries, which may lead to the omission of locally-important invasive species. Thus, we conducted searches in the JUDGIT! database (
We re-classified the type of costs associated with the entries by dividing them into two categories: "Damage" and "Management". "Damage" includes the economic loss caused by the invasive alien species and the expenses incurred to repair its impacts, while "Management" includes the expenses associated with managing invasive alien species itself, including prevention, eradication, control, research, buying equipment and environmental education to promote a better understanding of invasive species management. These two categories are then further divided into two categories: "Human" and "Biodiversity", where "Human" refers to the costs directly related to human livelihood-impacted sectors, such as agriculture, fisheries, forestry and human health. "Biodiversity" refers to the costs with respect to natural ecosystems, including the impact of invasive species on native species and ecosystem services (e.g. ecotourism). The classification scheme is shown in Suppl. material
We first compared the economic costs reported for each taxonomic group using the Class and species taxonomic classification. Second, to examine the annual change in economic costs, we plotted the costs against the year. Most of the Japanese entries are based on projects conducted by the government, in which the temporal unit of entries is the Fiscal Year (e.g. FY2017 = 2017 April – 2018 March). Here, for the sake of convenience, we treated the fiscal year as the year of the beginning period (FY2017 = 2017). Some of the entries in the database described total costs over multiple years. To determine the annual costs, we used the function "expandYearlyCosts" from the invacost package (
We obtained a total of 630 cost entries, of which 328 were from the non-English database and 302 from the search performed for this study (there were no recorded costs in English). Based on these entries, invasive species cost a total of 728 million USD (2017 value) to the Japanese economy from 1965 to 2017. These entries came from 33 documents and 16 authors (Suppl. material
The number of entries (Fig.
Breakdown of the number of cost entries (a) and the amount of costs (US$) (b) induced by biological invasions. Damage_Biodiversity and Damage_Human represent damage caused by biological invasions to biodiversity and human livelihood, respectively. Management_Biodiversity and Management_Human represent managements for biodiversity and human livelihood, respectively.
A total of 54 invasive species had reported costs (Fig.
Taxonomic comparison of the number of cost entries (a) and the amount of cost (b) by species. Damage_Biodiversity and Damage_Human represent damage caused by biological invasions to biodiversity and human livelihood, respectively. Management_Biodiversity and Management_Human represent management for biodiversity and human livelihood, respectively. The square frames grouped, from top to bottom, into invasive mammals, birds, reptiles, amphibians, fishes, insects, crustaceans, gastropods, flatworms, nematodes and plants.
For the economic cost by taxonomic groups, insects prominently had the largest amount of total costs, followed by mammals and nematodes (Fig.
Annual changes in the number of expanded entries and the amount of economic costs show that the reported costs began in 1965 (Fig.
Annual change in the number of cost entries (a) and the amount of costs in US$ (b). Damage_Biodiversity and Damage_Human represent damage caused by biological invasions to biodiversity and human livelihood, respectively. Management_Biodiversity and Management_Human represent management for biodiversity and human livelihood, respectively.
Comparing of the number of entries between the mainland and islands showed that the mainland had more reported cost entries than the islands in relation to Damage_Human and Management_Human, whereas only the cost entries for Damage_Biodiversity were higher in the islands (Fig.
Comparison of (a) the mainland and islands for the number of cost entries (b) the amount of costs in US$ (c) the number of cost entries per unit area and (d) the amount of costs per unit area. Damage_Biodiversity and Damage_Human represent damage caused by biological invasions to biodiversity and human livelihood, respectively. Management_Biodiversity and Management_Human represent management for biodiversity and human livelihood, respectively.
This study is the first attempt to analyse the recorded economic costs of biological invasions in Japan, which only used sources in the Japanese language: 630 cost entries with a total economic cost of 728 million USD (2017 value, equivalent to 62 billion JPY). The following are major findings in this study. First, damage costs caused by biological invasions tend not to be assessed as frequently as management costs and are more underestimated. Second, despite the numerous entries, an overwhelmingly small amount of the management budget was allocated to biodiversity conservation compared to protecting human livelihood. Third, budgets have been intensively invested in invasive species management on islands, which reflects the vulnerability of small island ecosystems and economies to biological invasions. Finally, the recorded costs seemed to be generally greatly underestimated, mainly due to the limited access to cost information.
The costs associated with human livelihoods were much higher than those associated with biodiversity. Scrutinising the nature of these costs suggests that Japan is still spending much more money on enduring or repairing damage directly related to human livelihoods rather than focusing on ecosystem conservation. In Japan, the Alien Species Act was enacted in 2005 (
This study revealed that the costs per unit area were disproportionately higher on islands. As some costs incurred on islands may be reported in the costs for the mainland (see Methods), the costs reported on islands are underestimated relative to the mainland costs. To conserve native species on islands, Japan has invested a higher amount of money in managing invasive species, such as the management projects for invasive rats, goats and anole in the Ogasawara Islands (
In general, the economic costs of biological invasions tend to be underestimated, because some are difficult to assess (e.g. costs incurred for biodiversity), even if they can exert long-term indirect impacts on humans (
In this study, the overall management costs were higher than the damage costs in terms of both the number of cost entries and the amount of costs. The major difference between management and damage costs is that the former is an expense for managing biological invasions, which can be assessed by summing up the recorded budgets for human actions, whereas the latter is an economic loss caused by biological invasions, which requires a scientific approach and administrative system in order to be evaluated. For example, while management costs have been reported for many years, damage costs only began to be recorded in around 2000, when the Ministry of Agriculture, Forestry and Fisheries set up the national system to report the economic costs of crop damage by wildlife (
Insufficient data accessibility can also lead to underestimations. It is, therefore, a major limitation of this first synthesis of the costs of invasive species in Japan. The measures targeting invasive alien species in Japan, which are mainly based on the three laws: “Act on the Prevention of Adverse Ecological Impacts Caused by Designated Invasive Alien Species”, “Protection and Control of Wild Birds and Mammals and Hunting Management Law” and “Act on Special Measures for Prevention of Damage Related to Agriculture, Forestry and Fisheries Caused by Wildlife” have been conducted at all levels of government, including the national government, 47 prefectural governments and 1,741 local municipal governments (
Even if the costs are published on the internet, they are not always listed in the dataset. For example, a document in the database summarising the contents of the budget for biological invasion management, based on “Act on the Prevention of Adverse Ecological Impacts Caused by Designated Invasive Alien Species”, included a total of 2,512,000,000 JPY (2012–2017), whereas the amount of costs listed in our dataset (Suppl. material
To access such data, it is necessary to conduct comprehensive and labour-intensive surveys of paper-based materials, as well as individual interviews with countless local government officials. In order to improve this situation, it is important to establish systems that allow the reporting of invasion costs in a widely-available form, such as a platform for indexing and searching administrative data and an open library to enable not only scientists, but also practitioners and decision-makers to easily access the economic costs.
Given the current situation where information from non-English sources has been ignored, becoming a barrier to the advancement of ecological scientific knowledge biodiversity conservation (
Japan is one of the countries with a lower proportion of English speakers (
We showed the economic costs of biological invasions in Japan for various taxonomic groups and ecosystems over a period of more than 50 years. These costs mainly focused on humans (as opposed to biodiversity), management (as opposed to damage) and small islands (as opposed to the mainland). This study also showed that the economic costs of biological invasions may be grossly underestimated. Therefore, accepting the amount of economic costs provided here will inevitably lead to an underestimation of the impact of invasive species. To bridge this gap, it is necessary to continue efforts to compile records of economic costs, which will allow us to appropriately balance the impact of invasive species on the one hand and the scale of management measures on the other, hence providing more realistic guidelines for tackling the issue of biological invasions. The findings in this study are not only specific to Japan, but also widely applicable to other countries.
We would like to thank Gauthier Dobigny for the translation of the abstract into French. YW was funded by the Environment Research and Technology Development Fund (JPMEERF20184004) of the Environmental Restoration and Conservation Agency of Japan. The French National Research Agency (ANR-14-CE02-0021) and BNP-Paribas Foundation Climate Initiative funded the InvaCost project, which allowed the development of the InvaCost database, including the non-English version. The present work was conducted following a workshop funded by the AXA Research Fund Chair of Invasion Biology and is part of the AlienScenario project funded by BiodivERsA and Belmont-Forum Call 2018 on biodiversity scenarios. Funding for the contracts of EA and LBM contracts come from the AXA Research Fund Chair of Invasion Biology. CD was funded by the BiodivERsA-Belmont Forum Project “Alien Scenarios” (BMBF/PT DLR 01LC1807C).
Table S1. Dataset of the economic costs of biological invasion in Japan
Data type: database
Explanation note: The dataset of the economic costs of biological invasion in Japan extracted from the InvaCost_v3.0 (openly available at https://doi.org/10.6084/m9.figshare.12668570) and the additional search in this study.
Definition of the categorisation of economic costs
Data type: adittional data
Explanation note: Damage_Biodiversity and Damage_Human represent damage caused by biological invasions to biodiversity and human livelihood, respectively. Management_Biodiversity and Management_Human represent management for biodiversity and human livelihood, respectively. Categories in each cost entry are shown in Suppl. material