2025 年 17 巻 p. 96-126
This study aimed to investigate how native and alien organisms, particularly en-dangered and invasive alien species, are treated in relation to biodiversity and its conservation in Basic Biology courses at Japanese upper secondary schools. To this end, the current Japanese Upper Secondary School National Curriculum Standard (USS-NCS), its Guidelines and currently used Basic Biology textbooks were ex-amined. The current USS-NCS does not address the treatment of native and alien organisms like its predecessor, but its Guidelines cite the introduction of alien spe-cies as an example of anthropogenic disturbances and recommend that its adverse effects on native organisms be explained in Basic Biology course. In all ten Basic Biology textbooks surveyed, the terms "native organisms", "endangered species", "Red List", and "alien organisms" were found in the sections related to biodiversity and its conservation. In addition, some terms related to them, such as "endemic species", "rare species", "Red Data Book", "the IUCN Red List of Threatened Spe-cies", "the Invasive Alien Species (IAS) Act", and "designated invasive alien species (DIAS) under the IAS Act", were found in more than half of these textbooks. However, some textbooks were lacking a sufficient explanation of some of these terms. Some textbooks also were lacking the explanation of the measures to con-serve native organisms and those to combat the deleterious impacts of invasive alien species. Among organisms appearing in the sections related to biodiversity and its conservation of these textbooks, 71 species (55 animals, 15 plants and one protist) were extinct or endangered ones in Japan though some of them were not clearly mentioned as endangered ones. There was almost no mention of extinct or en-dangered species overseas, probably because the Basic Biology course focuses on ecosystem problems within Japan. There were 52 species (38 animals and 14 plants) of DIAS and "invasive alien species that require control measures" found in the ten textbooks. Some of them also were not clearly stated as these kinds of alien species. The number of extinct or endangered native species and invasive alien species in Japan appearing in each textbook varied widely, ranging from nine to 31 and from two to 33, respectively. Description of "alien species of domestic origin" was found in only three textbooks and description of "species native to Japan as invasive alien species overseas" was found in only two textbooks. The results of the survey of current Basic Biology textbooks indicate that emphasis is placed on the treatment of invasive alien species, reflecting the descriptions in the USS-NCS Guidelines. There were also many cases where terms were not sufficiently defined or explained, and some essential information on native and alien organisms was lacking. Although an increase in endangered species is not the only indication of a decline in biodiversity in an ecosystem, it would be good to have more description of the protection and conservation of native species. As an example of biodiversity conservation, text-books should stress that properly managed ecosystems, such as SATOYAMA (countryside forests) and wetlands, have a high level of biodiversity.
Since biodiversity conservation is one of the significant challenges facing modern society (Biodiversity Center of Japan, undated, see website list; Stockholm Resilience Centre, undated, see website list), it has been pointed out that it is an important topic not only in environmental education (Numata, 1990; Ubukata, 2011; Navarro-Perez and Tidball, 2012) but also in biology education in schools (Heavenlin et al., 2015; Shoji and Nagashima, 2015; Børresen et al., 2022). To find out what topics related to biodiversity and its conservation are being taught in Japanese upper secondary biology classes, we have been conducting a survey of the current Upper Secondary Schools National Curriculum Standard (USS-NCS), its Guidelines, and Basic Biology and Advanced Biology textbooks currently in use. We have already reported on the results of an investigation of how terms related to biodiversity and its conservation are used in these materials (Katayama and Nakamichi, 2024).
When teaching biodiversity and its conservation, it seems important which organisms are to be considered. Research on organisms as teaching materials for biodiversity and its conservation in Japan seems to have focused more on alien organisms than on native organisms. For example, Higa has conducted a series of studies on the use of alien organisms, particularly invasive ones, in school biology education, and reported that the previous USS-NCS published in 2009 did not mention alien organisms, although its Guidelines made such a mention (Higa, 2019). Indeed, the previous USS-NCS Guidelines recommended that “in Basic Biology, students be made aware that anthropogenic disturbance of ecosystems through the introduction of alien species can lead to a loss of biodiversity, and in Advanced Biology, such disturbance can lead to the extinction of local populations” (Ministry of Education, Culture, Sports, Science and Technology, Japan <MEXT>, 2009b, p. 80 and p.92). As a result, topics related to alien organisms were included in all Basic Biology and Advanced Biology textbooks used until the 2021 academic year (Higa, 2019). He also conducted research on the same topic on the current USS-NCS published in 2018 and its Guidelines published in 2021, reporting that while the current USS-NCS also does not mention alien organisms, its Guidelines do include the term (Higa, 2024). The current USS-NCS Guidelines recommend the same for Basic Biology as the previous Guidelines (MEXT, 2021, p. 125), but do not mention alien species for Advanced Biology. However, some topics related to alien organisms are still included in all currently used Advanced Biology textbooks as well as Basic Biology textbooks (Higa, 2024).
In addition, in secondary education in Japan, there has been considerable research on the development of educational strategies, materials, and experiments to teach about invasive alien organisms (Ohshika et al., 2007; Suzue, 2007; Kisakibaru, 2012; Sakuraba et al., 2013; Doi and Hayashi, 2015; Ito et al., 2015; Mori, et al., 2017; Higa, 2018; Kato, 2018; Wada, 2019; Sasaki et al., 2020; Kurabayashi et al., 2021; Shimabe and Imai, 2021, 2022), as well as on students' perceptions of invasive alien species and the threats they pose (Yamanoi et al., 2016a; Murase and Kato, 2020;). Meanwhile, there have been only a few reports on the use of native organisms, particularly endangered species, in upper secondary biology classes (Hayakawa, 2006; Fuse, 2015a; Sakuraba et al., 2013; Umezawa and Tsunoda, 2022) and environmental education for upper secondary students (Fukata et al., 2018).
Kato (2011) investigated what kinds of organisms, that included alien species as well those species in need of conservation, were listed and how their use in upper secondary school biology textbooks changed over time between 1947 and 1999. After Kato’s work, there have been two reports on what kinds of organisms are considered in Basic Biology textbooks which conformed to the previous USS-NCS published in 2009. Sakuraba et al. (2013) investigated what kinds of organisms appear in the section "Ecosystem Balance and Conservation" of nine Basic Biology textbooks published in 2011 or 2012 and reported that numbers of different types of organisms, that are listed in each textbook, ranged 11 to 60. As will be described later, the names of organisms that appear in the textbooks sometimes may not be species names, but their survey results included some unclear information about this. Doi and Hayashi (2015) also investigated what kinds of organisms are listed in three Basic Biology textbooks published in 2012 (three of the textbooks examined by Sakuraba et al., 2013) and reported that these textbooks included 49 alien species, 19 of which were invasive alien species. However, it is unclear whether these organisms were mentioned in relation to biodiversity and its conservation, or whether they were clearly stated as alien species in these Basic Biology textbooks.
Considering the shortcomings of these two previous studies, I surveyed currently used upper secondary biology textbooks to examine how native and alien organisms are treated in relation to biodiversity and its conservation. The survey was conducted on both Basic Biology and Advanced Biology textbooks, but since the survey results were deemed too extensive to report in a single paper, the survey results for Advanced Biology textbooks will be reported separately. Although the treatment of alien organisms in the previous and current USS-NCS and their Guidelines has already been investigated and reported by Higa (2019 and 2024), this time it was investigated again together with how native organisms are treated in these materials. When compiling the survey data, it was sometimes difficult to determine whether the species mentioned in the textbooks were native to Japan or not, so this paper focuses on which endangered native species and invasive alien species are mentioned and how they are treated in the sections on biodiversity and its conservation.
PDF files of the previous USS-NCS (MEXT, 2009a) and its Guidelines (MEXT, 2009b), as well as the current USS-NCS (MEXT, 2018) and its Guidelines (MEXT, 2021), were downloaded from the MEXT website. Ten Basic Biology textbooks published in 2022 (See the list in "BASIC BIOLOGY TEXTBOOKS SURVEYED") were used for textbook survey. Details of these textbooks have been provided by our previous report (Katayama and Nakamichi, 2024). As in the previous paper, each textbook will be referenced by number in this paper.
Data CollectionTerms related to native and alien organisms that are mentioned in relation to the topics of biodiversity and its conservation in these textbooks were collected, and how these terms are defined and explained was investigated. Some Basic Biology textbooks provide English translations for key terms, but other terms are written in Japanese. Thus, these terms were translated into English and synonymous terms were defined for their discrimination (See Appendix 1). The English translations and definitions of terms were mainly based on those in a document provided by the Ministry of the Environment Japan <MOE> (MOE, 2004a), the Act on the Prevention of Adverse Ecological Impacts Caused by Designated Invasive Alien Species (Invasive Alien Species Act in short; abbreviated as the IAS Act) enacted in 2004 and amended in 2014 (MOE, 2014), and the Environmental Glossary provide by the Environmental Innovation Information Center <EIC> (EIC Net, undated, see website list). The terms collected in this study were not necessarily just single words or compound nouns. Some textbooks use expressions like "an organism which is rare" instead of the compound noun "rare species." In such cases, it was determined that the term "rare species" would be used.
The names of organisms that appear in the unit "Diversity of Organisms, and Ecosystems" of Basic Biology textbooks were collected as organisms used to explain content related to biodiversity and its conservation.
Data AnalysisThe method for analysing the descriptions of terms and topics related to native and alien organisms in textbooks was based on Higa (2019). I considered not only whether the definition or explanation of each term is provided, but also whether the definition is clear and the explanation is sufficient. In some cases, I had to make my subjective judgement as to the clarity of the definition of term and the sufficiency of the explanation of term.
To determine whether the organisms are extinct or endangered native species, the Red List compiled in 2020 under the Act on Conservation of Endangered Species of Wild Fauna and Flora (commonly known as the "Species Conservation Law," enacted in 1992) by the MOE (abbreviated as the MOE Red List 2020; MOE, 2020) was used. Local governments and NGOs in Japan also compile their own Red Lists, which may include species that are not listed in the MOE Red List 2020, but these were not referred to in this study. For endangered species overseas, the Red List of Threatened Species provided by the International Union for Conservation of Nature and Natural Resources <IUCN> (abbreviated as the IUCN Red List; IUCN, undated, see website list) was referenced. For organisms that were thought to be alien species in Japan, the List of Alien Species that May Cause Damage to Japan's Ecosystems (abbreviated as the LIST; MOE, 2015; see Appendix 1 for details) and the List of Regulated Living Organisms under the Invasive Alien Species Act (MOE, 2024) were referenced to determine whether they fell into any of the categories of invasive alien species in Japan.
Generally, in textbooks surveyed, each species is shown by its standard domestic name written in Japanese. However, it could sometimes be difficult to determine whether the Japanese name listed refers to a species or a genus or family. For example, TANAGO is the name of a Japanese native fish species Acheilognathus melanogastera which belongs to the subfamily Acheilognathinae, but the name is also used as a general name for fish in this subfamily. When the name of an organism presented was not a species name but a taxonomic group (e.g. genus), if a species belonging to that taxonomic group is designated as an endangered species or an invasive alien species, the organism was considered to be also designated.
Notation of Organisms’ NamesIn this paper, when writing the name of an organism for the first time, the scientific name will be written, followed by the common English name in parentheses, unless the Japanese name written in the textbook is not the species name. If the organism is endemic to Japan and does not have a common English name, the scientific name is followed by the standard Japanese name in upper case in parentheses. From then on, either the common English name or the standard Japanese name is given. The scientific name and common English name of each organism were primarily based on the MOE Red List 2020, the List of Regulated Organisms under the IAS Act (MOE, 2024), and the IUCN Red List.
It was found that the current USS-NCS make no reference to either native or alien organisms; this also applied to the previous USS-NCS. However, its Guidelines contain statements related to alien organisms for the "Ecosystem Balance and Conservation" section of the unit "Diversity of Organisms, and Ecosystems" of Basic Biology, namely, “To show how anthropogenic disturbance can damage the diversity of organisms, present materials, for example, showing the ecology of alien fish such as the largemouth bass and the changes in the number of native fish species and populations after their introduction, so that students can recognize how the introduction of alien organisms has affected the number of species and populations of native organisms (MEXT, 2021, p. 125)” which is almost identical to its predecessor (MEXT, 2009b, p. 80; see INTRODUCTION section). As such, in the current USS-NCS Guidelines, the terms native and alien organisms (species) were found. The introduction of alien organisms is cited as an example of anthropogenic disturbance and even the name of Micropterus salmoides (largemouth bass) is mentioned. However, regarding native organisms, it is only stated that they are being affected by introduced alien species, and there is no mention of native species that are at risk of extinction at all. In the current USS-NCS Guidelines, this unit is the only one that mentions the names of specific organisms other than humans, and in addition to the largemouth bass, the names of starfish, Enhydra lutris (sea otter), and sea urchin also appear.
Terms Related to Native Organisms and Endangered Species Found in TextbooksThe current Basic Biology textbooks include some terms related to native organisms with their definitions or explanations mainly in the chapter "Ecosystems and Their Conservation" of the unit "Diversity of Organisms, and Ecosystems" (Table 1). All textbooks include the term native organisms (or native species) - from now on, every term found in the textbooks will be underlined -, seven list it in their indexes, and four treat it as a key term. Five textbooks include the term endemic species, and one includes the term primeval species, both of which are used in conjunction with the term native organisms. Textbook #5 lists both terms along with native organisms in its index. Five textbooks include the term rare species, and one of them (Textbook #9) lists it in its index. However, explanations or definitions of each term are often missing or insufficient, making the differences in the definitions of each term unclear.
All textbooks include the term endangered species, and eight treat it as a key term. However, most textbooks only provide a brief explanation of endangered species and do not provide categories for endangered species (near threatened, NT; vulnerable, VU; endangered, EN; critically endangered, CR). All textbooks except Textbook #4, mention the terms Red List and Red Data Book, most of them list both terms in their indexes, and Textbook #9 treats both as key terms. Textbook #4 treats the term Red List as a key term but lack the term Red Data Book. In most textbooks, measures for the protection and/or conservation of native species are only briefly discussed in relation to countermeasures against invasive alien species or environmental assessments. Although not shown in Table 1, Textbook #9 mentions the Species Conservation Law, provides some explanations, and lists it in its index.
| Term or Explanation | Basic Biology textbook surveyed | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| #1 | #2 | #3 | #4 | #5 | #6 | #7 | #8 | #9 | #10 | |
| "Native organisms" | ● | ● | ◎ | ● | ◎ | ● | ◎ | 〇 | 〇 | 〇 |
| Explanation of native organisms | 〇 | 〇 | △ | 〇 | 〇 | 〇 | 〇 | △ | 〇 | |
| "Endemic species" | 〇 | 〇 | ◎ | 〇 | 〇 | |||||
| Explanation of endemic species | 〇 | 〇 | 〇 | 〇 | ||||||
| "Primeval species" | ◎ | |||||||||
| Explanation of primeval species | ||||||||||
| "Rare species" | 〇 | 〇 | 〇 | ◎ | 〇 | |||||
| Explanation of rare species | 〇 | |||||||||
| "Endangered species" | 〇 | 〇 | ● | ● | ● | ● | ● | ● | ● | ● |
| Explanation of endangered species | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 |
| "Red List" | ◎ | ◎ | ◎ | ● | ◎ | 〇 | ◎ | ◎ | ● | 〇 |
| "Red Data Book" | ◎ | ◎ | ◎ | ◎ | 〇 | ◎ | ◎ | ● | 〇 | |
| Explanation of Red List | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | △ | 〇 | 〇 | |
| Explanation of Red Data Book | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | 〇 | |
| Categories of endangered species | 〇 | 〇 | 〇 | |||||||
| Measures to conserve or to preserve native organisms | 〇 | 〇 | 〇 | △ | 〇 | 〇 | 〇 | |||
| “IUCN Red List of Threatened Species” | 〇 | 〇 | 〇 | 〇 | 〇 | |||||
| Explanation of the IUCN Red List of Threatened Species | 〇 | △ | ||||||||
〇: found in the text; ◎: listed in the index; ●: treated as a key term; △: presented in the text, but insufficient.
Five textbooks mention the term IUCN Red List as a global list of endangered species or indicate the existence of such a list, but only one (Textbook #1) provides a sufficient explanation of it. Even that textbook does not mention the IUCN categories of extinct and endangered species (EX, EW, CR, EN, VU, NT) that are used worldwide.
Japanese Endangered Species Found in TextbooksThe total number of extinct and endangered species native to Japan listed in the unit "Diversity of Organisms, and Ecosystems" in ten Basic Biology textbooks was 71, including 55 animals, 15 plants, and one protist (Appendix 2). However, since no textbook mentions some of them as extinct or endangered in their sections, the number of textbooks which clearly state that each species is endangered is shown in parentheses in Appendix 2. There were 14 species that are designated as endangered (CR, EN, VU, NT) on the MOE Red List 2020 but are not clearly stated as endangered in any textbooks: two mammal species, four bird species, three fish species, four insect species, and one plant species (Appendix 2, "0" in parentheses). In textbooks, they are introduced as keystone species such as the sea otter, which is also used to explain a phenomenon called indirect effects; organisms such as the giant water bug and the great purple emperor that inhabit SATOYAMA (countryside forests) areas; species such as HONMOROKO found in a survey of organisms inhabiting a certain place; organisms such as the little tern and the osprey involve in bioaccumulation. Textbook #9 mentions Meimuna boninensis (Ogasawara cicada) as an example of “populations of native species are decreasing due to the invasion of an alien species (the green anole).” This species was designated a National Natural Monument in 1970 under the Law for the Protection of Cultural Properties because it is endemic to the Ogasawara Islands (Biodiversity Center of Japan, undated, see website list) which consists of more than 30 islands in the Pacific Ocean, about 1,000 km south-southeast of Tokyo, but it is not listed on the MOE Red List 2020, so it was not included in the present tabulation.
Two mammal species (the Tsushima wildcat and the Amami rabbit) and four bird species (the Okinawa rail, the Japanese crest ibis, the rock ptarmigan, and the short-tailed albatross) are mentioned as endangered species in five or more textbooks. On the other hand, 20 animal species and 12 plant species are mentioned as endangered only in one textbook. Two textbooks (#3 and #10) list MARIMO, a protist which inhabits in Lake Akan in Hokkaido and was designated a National Natural Monument in 1952 (Agency for Cultural Affairs, Japan, undated, see website list), as an endangered species. The Japanese native endangered species listed in each textbook were not necessarily species at a high risk of extinction as ranked CR or EN (Appendix 2).
The number of Japanese native species listed on the MOE Red List 2020 in each textbook varied considerably, ranging from nine to 31 (average 17). Among them, the species that are clearly indicated as extinct or endangered species in each textbook ranged from two to 24 (average 12). In every textbook, animal species appear more frequently than plant species, and in one textbook (#6), plant species are not mentioned at all (Table 2).
| Textbook | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| #1 | #2 | #3 | #4 | #5 | #6 | #7 | #8 | #9 | #10 | |
|
|
10 (8) | 8 (1) | 14 (8) | 17 (15) | 18 (14) | 12 (5) | 26 (20) | 14 (8) | 17 (9) | 16 (11) |
|
|
4 (4) | 1 (1) | 2 (2) | 1 (1) | 1 (1) | 5 (4) | 1 (1) | 2 (2) | 3 (2) | |
|
|
1 (1) | 1 (1) | ||||||||
|
|
14 (12) | 9 (2) | 17 (11) | 18 (16) | 19 (15) | 12 (5) | 31 (24) | 15 (9) | 19 (11) | 20 (13) |
In the unit "Diversity of Organisms, and Ecosystems" many organisms that are not native to Japan were found. Among these organisms, 24 species or taxa were listed on the IUCN Red List. These were 19 mammal species or taxon, three bird species, one reptile taxon, and one plant species (Appendix 3). However, in textbooks, most of them are used to explain the world’s biomes, and only the passenger pigeon and orangutans (there are three species listed on the IUCN Red List) are mentioned in relation to species extinction due to human activities: the former is introduced by two textbooks (#7 and #8) as an example of extinction due to hunting and the latter are introduced by three textbooks (#1, #2, and #4) as being at risk of extinction due to deforestation of tropical rainforests.
Terms Related to Alien organisms Found in TextbooksAll Basic Biology textbooks include the term alien organisms (alien species) in the main text, list it in their indexes, and treat it as a key term (Table 3). All textbooks explain that alien species are organisms which have been introduced artificially, whether intentionally or not, into non-native habitats. However, only four (#1, #2, #9, and #10) out of ten textbooks explain sufficiently how alien organisms generally are introduced or invade an ecosystem. Among them, only two textbooks (#9 and #10) further provide specific examples of invasive alien species and explanations of how they were brought into or invaded Japan. All textbooks explain that if an alien species invades and becomes established, it may have an adverse impact on the native ecosystem, but they provide only one or a few specific examples of such adverse effects. On the other hand, Textbook #4 describes that alien organisms do not necessarily give an adverse impact to human beings, indicating that there are a lot of useful organisms, such as cultivated crops and livestock, among them. Regarding countermeasures against invasive alien species in Japan, nine textbooks discuss one or a few examples of invasive alien species control in Japan. The most representative examples are the eradication of two designated invasive alien species, the Small Indian mongoose and the largemouth bass. Eight textbooks refer to the existence of a law for preventing adverse impacts on ecosystems by alien species and explain the purpose of the law and some of the measures it provides, but one of them (textbook #8, △ mark in Table 3) does not mention the name of the law, i.e., the IAS Act. Two of the remaining seven textbooks (#9 and #10) list the IAS Act in their indexes. These eight textbooks mention the term designated invasive alien species (DIAS) that is designated under the law, seven list it in their indexes, and two treat it as a key term. However, only three textbooks (#3, #9, and #10) include the term invasive alien organisms with an explanation, and list it in their indexes, and two (#9 and #10) treat it as a key term. Although the term alien species of domestic origin (from now on, the term "domestic alien organisms" will be used; see Appendix 1 for details) was not found in any of the textbooks, three textbooks (#1, #6, and #9) mention some adverse effects of domestic alien organisms. Textbook #9 states that alien organisms include not only species from overseas, but also native species from other parts of Japan.
| Term or Explanation | Textbook surveyed | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| #1 | #2 | #3 | #4 | #5 | #6 | #7 | #8 | #9 | #10 | |
| “Alien organisms (species)” | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● |
| Explanation of alien organisms (species) | ○ | ○ | ○ | ○ | ○ | ○ | ○ | ○ | ○ | ○ |
| Routes/ history of introduction or invasion of alien organisms (species) | ○ | ○ | △ | ○ | ○ | |||||
| Effects of alien organisms (species) | ○ | ○ | △ | ○ | ○ | ○ | ○ | ○ | ○ | ○ |
| Measures against invasive alien species in Japan | △ | △ | △ | ○ | ○ | ○ | △ | ○ | ○ | |
| “Invasive Alien Species (IAS) Act” | ○ | ○ | ○ | ○ | ○ | △ | ◎ | ◎ | ||
| “Invasive alien species” | ◎ | ● | ● | |||||||
| Explanation of invasive alien species | ○ | ○ | ○ | |||||||
|
“Designated invasive alien species” under the IAS Act |
◎ | ◎ | ◎ | ○ | ● | ● | ◎ | ◎ | ||
|
Explanation of designated invasive alien Species |
○ | ○ | ○ | ○ | ○ | ○ | ○ | ○ | ||
| Mention of domestic alien organisms | ○ | ○ | ○ | |||||||
〇: found in the text; ◎: listed in the index; ●: treated as a key term; △: presented in the text, but insufficient.
Although not shown in Table 3, textbook #3 even mentions the List of Alien Species that May Cause Damage to Japan's Ecosystems (the LIST) and explain that, to help with countermeasures, the LIST classifies "invasive alien species that require control measures" as follows: those to be prevented from entering, those requiring emergency measures, and those requiring priority measures.
Invasive Alien Species Found in TextbooksAmong alien species that appear in the unit "Diversity of Organisms, and Ecosystems" in the surveyed textbooks, those designated as invasive alien species under the IAS Act (DIAS) or included in the LIST are shown in Appendix 4. Thirty-eight invasive alien animal species were found in these ten textbooks, the majority of which were DIAS, while only 14 invasive alien plant species were found, half of which were DIAS.
All invasive alien animals listed in Appendix 4 are mentioned as alien species in the textbooks. However, some textbooks list the names of invasive alien animals but do not state that they are DIAS or included in the LIST. For example, all textbooks mention the largemouth bass following the recommendation of the USS-NCS Guidelines (MEXT, 2021, p. 125), but only four of them note that this species is a DIAS. DIAS other than the largemouth bass found in five or more textbooks included two mammals (the small Indian mongoose and the raccoon), one reptile (the green anole), one fish species (the bluegill), and one insect species (the red imported fire ant). Textbook #8 specifically indicates that some invasive alien animal species, such as the red imported fire ant and the red-back widow spider, are harmful to human beings.
The seven designated invasive alien plant species shown in Appendix 4 are noted that they are DIAS in every textbook that includes them. Among them, four species, the water lettuce, the bur cucumber, the lance-leaved coreopsis and the golden glow, were found in multiple textbooks, but none were found in more than five textbooks. The other seven alien plant species in Appendix 4 are listed in the LIST, but, except for the cut-leaf evening primrose, the textbooks in which they were found do not mention that they are invasive alien plants that require control measures. Furthermore, the textbooks that include the Brazilian elodea, the common water hyacinth and the annual fleabane do not even mention that they are alien species (marked X in Appendix 4). In Textbook #1, Ambrosia artemisiifolia (ragweed) and Conyza sumatrensis (Sumatran fleabane) are given as examples of the plants that appear at the initial stages of secondary succession and explained that they are alien species. As discussed below, they were previously considered invasive alien species, but have now been delisted and are therefore not included in Appendix 4.
The number of invasive alien species found in each textbook varied considerably, ranging from two to 33, but the number of species which are clearly stated as invasive in each textbook was from zero to 31 (average 11). Every textbook lists more animal species than plant species, and in one textbook (#2) does not mention any alien plant species at all. This textbook and another textbook (#1) published by the same publisher do not state that, even though the alien species listed are DIAS, they are so (Table 4).
| Textbook | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| #1 | #2 | #3 | #4 | #5 | #6 | #7 | #8 | #9 | #10 | |
|
|
2 (0) | 2 (0) | 10 (5) | 21 (21) | 4 (1) | 4 (1) | 27 (26) | 3 (2) | 8 (7) | 7 (5) |
|
|
2 (0) | 3 (2) | 6 (4) | 1 (1) | 1 (1) | 6 (5) | 1 (1) | 1 (1) | 2 (2) | |
|
|
4 (0) | 2 (0) | 13 (7) | 27 (25) | 5 (2) | 5 (2) | 33 (31) | 4 (3) | 9 (8) | 9 (7) |
Regarding domestic alien organisms, only Textbook #1 and Textbook #6 respectively present a specific example: vegetation destruction caused by introduced goats in the isolated Ogasawara Islands and genetic disturbance of a local firefly population.
Textbook #3 describes that Miscanthus sinensis (Japanese silver grass or Chinese silver grass), Pueraria montana var. lobata (kudzu), and “the carp,” as Japanese species that have been introduced and become established in the USA. Textbook #9 also gives the kudzu as an example of invasive alien species in the USA.
In the previous USS-NCS Guidelines, for the section "Ecosystem Balance and Its Conservation" in Basic Biology, it was stated that “students should be made to understand the importance of ecosystem conservation by showing examples of ecosystems that have been disturbed and biodiversity has changed due to human activities such as the introduction of alien species and deforestation” (MEXT, 2009b, p.80). The current USS-NCS Guidelines (MEXT, 2021, p. 125) state almost the same thing for the section "Ecosystem and Its Conservation" in Basic Biology. Furthermore, in both cases, the adverse effects of the introduction of alien species are explained using the largemouth bass as an example. However, there are only a few descriptions of native organisms, and no mention of endangered native species, which may have reflected a remarkable difference in the number of studies between on teaching invasive alien organisms versus teaching native organisms in secondary education (See INTRODUCTION section). Although the protection of a specific endangered species does not directly lead to the conservation of native ecosystems, the protection of native organisms, especially endangered species, and the conservation of their environments need to be addressed in more detail in the USS-NCS Guidelines in relation to the conservation of native ecosystems.
Treatment of Native Organisms in Current Basic Biology TextbooksAlthough not required by the current USS-NCS Guidelines, all Basic Biology textbooks contain descriptions of native organisms, including endangered species. However, reflecting the content of the USS-NCS Guidelines, the treatment of native organisms seems to be insufficient compared to alien organisms. First, native organisms are described somewhat less than alien organisms, with unclear definitions of the term. In addition, as pointed out in our previous paper (Katayama and Nakamichi, 2024), all ten textbooks list the term alien organisms (or alien species), which is the antonym of native organisms, in their indexes and treat it as a key term (Table 3), whereas textbooks list the term native organisms (or native species) in their indexes were seven and those treat it as a key term were only four (Table 1). Furthermore, in textbooks that use the synonymous terms, endemic species and primeval species, in addition to native organisms, the definitions of these terms are missing or unclear. Since the USS-NCS Guidelines request a reduction in the number of terms used in Basic Biology textbook (MEXT, 2021, p.127), it is necessary to consider the appropriateness of using such similar terms.
Since the extinction of species endemic to a certain region or an increase in the number of endangered species in that region signifies a decline in the region's biodiversity, the USS-NCS Guidelines require that species extinction should be mentioned in the unit "Diversity of Organisms, and Ecosystems" of Basic Biology (MEXT, 2021, p.124). In response, all ten textbooks include the term endangered species, and eight of them treat it as a key term. The total number of endangered native species that appear in the ten textbooks (Appendix 2) was larger than the total number of invasive alien species that appear in these textbooks (Appendix 4). In all textbooks except for textbooks #4 and #7, the number of endangered native species exceeded the number of invasive alien species (Tables 2 and 4). Furthermore, if endangered species overseas (Appendix 3) were included, the total number of endangered species appearing in the unit "Diversity of Organisms, and Ecosystems" in each textbook would be much higher. Judging solely from the number of species and taxa listed in each textbook, endangered species appear to be receiving more favourable treatment than invasive alien species, but many of the endangered species overseas are not clearly stated to be in danger of extinction. There was a difference between the average number of endangered native species (17) and the average number of those that are clearly stated as endangered (12). This is because a considerable number of endangered native species listed in each textbook are also not presented as examples of endangered species, such as the sea otter. The sea otter is included in all the textbooks (Appendix 2) because the USS-NCS Guidelines stated that “It is possible to touch on the indirect effect through the food chain by presenting data showing the population density of sea urchins and seaweeds in environments with and without sea otters as top predators” (MEXT, 2021, p. 125). In this way, and as is the case with the largemouth bass, when the curriculum guidelines provide a specific example, textbook authors and editors tend to prioritize incorporating it in their textbooks.
All textbooks point out that direct and indirect effects of various anthropogenic disturbances, such as habitat destruction and fragmentation due to land development and deforestation, as well as the introduction and invasion of invasive alien species, are factors that lead to the extinction of species and the increase in endangered species. On the other hand, there is a hypothesis that a certain degree of natural disturbance enhances biodiversity (this is called the "Intermediate Disturbance Hypothesis") and two textbooks (#5 and #6) mention this hypothesis (Katayama and Nakamichi, 2024), though the USS-NCS Guidelines do not mention it at all. Textbooks #1 and #2 state that some organisms require a certain degree of disturbance, and cite the thoroughwort and the MIZUAOI, which grow in floodplains, as examples of species that are at risk of extinction due to habitat loss caused by river flood control works. Furthermore, all textbooks except Textbook #8 explain the importance of human management, which is a kind of anthropogenic disturbance, for the conservation of biodiversity in SATOYAMA areas. SATOYAMA, in the narrow sense, refers to forests or hilly areas close to the living areas where people obtained firewood, thatch or organic fertiliser, etc. It has become known worldwide through the SATOYAMA Initiative (Doshita, 2015; The Satoyama Initiative, undated, see website list). Nowadays, SATOYAMA is defined more broadly as areas “located in the rural areas of Japan where agriculture, forestry and fisheries are the main industries. They are known as socio ecological production landscapes and seascapes. They consist of production ecosystems like secondary forests, farmlands, irrigation ponds, and grasslands as well as human settlements (MOE, 2022, p.2).” Five textbooks list some endemic species in SATOYAMA areas that are properly managed by humans, in addition to explaining that these areas are rich in biodiversity. Some of these endemic species are designated as endangered species, but unfortunately, most of them are not stated as endangered in these textbooks. Kominami et al. (2013) suggested that SATOYAMA could be useful as a teaching material for biodiversity education and developed an inquiry activity model by using tree distribution data from a SATOYAMA secondary forest (Kominami and Muramatsu, 2016; Kominami, 2022). In addition, many cases of using SATOYAMA areas for environmental education and outdoor education have been reported in Japan (e.g., Fuse, 2015b; Shingai et al., 2021). Such previous studies would be useful for developing materials for teaching about biodiversity and its conservation in biology education at the secondary level.
The endangered native species marked with a diamond (◆) in Appendix 2 have been designated as Special Natural Monuments (JATAFF, undated, see website list) under the Law for the Protection of Cultural Properties enacted in 1950. Some of them are occasionally featured in television programs, newspapers, and magazines, so students may be familiar with them. Therefore, it seems reasonable that the Amami rabbit, the Japanese crested ibis, the rock ptarmigan, and the short-tailed albatross are listed as endangered native species in more than half of ten textbooks. However, many other endangered species are rare ones that live in remote islands, mountainous districts, or other isolated areas, so they possibly are unfamiliar to students. Although some textbooks, such as textbook #3, seemed to give priority to extinct species and species with critically endangered (CR) or endangered (EN) levels, most other textbooks seemed to list endangered native species regardless of their threat level and the criteria for selection were unclear. Since biology textbooks are used by students nationwide, it may be difficult to select the best endangered native species to be included in the textbooks. However, it is desirable to give priority to species with a high risk of extinction, such as CR or EN in the MOE Red List 2020 and, as Sakuraba et al. (2013) pointed out, to select species well-known among students as possible. In addition, consideration should be given to selecting representative species from each phylum.
Regarding the species to be introduced in the unit "Ecosystems and their Conservation," Sakuraba et al. (2013) and Fuse (2015a) suggested that it is appropriate to select species that inhabit in areas close to the students' living areas because such organisms are likely to attract students' interest and related reference materials will be easily available. Then, Sakuraba et al. (2013) gave two fish species, Acheilognathus typus (ZENI-TANAGO, CR) and Pungitius pungitius Omono type (IBARA-TOYOMI, CR), and one bird species, the black woodpecker (VU), as specific examples from their residential area, Akita Prefecture. Hayakawa (2006) introduced the Tokyo salamander as a versatile biological teaching material for his biology classes in an upper secondary school located near Tokyo and stated that continued rearing of the salamander in schools would contribute to the protection of endangered species. However, only one textbook introduces this species as an endangered one, possibly because the distribution area of this species is extremely limited. In a recent research report on the use of endangered species in the Ryukyu Islands, the Amami rabbit, the Iriomote wildcat, and the Okinawa rail, as teaching materials, Miyake (2024) pointed out that these endangered species are exposed to the threat of roadkill, the diversification and increase of predators and habitat destruction. Textbook #3 introduces the construction of underpass as a way to protect the Okinawa rail from roadkill. In the other studies on the development of teaching materials for biodiversity education so far, the native endangered species covered were fish such as the Tokyo bitterling (Fukata et al., 2018) and the killifish (Umezawa and Tsunoda, 2022). Most of these studies are quite recent and may not have been referenced when the current textbooks were compiled. However, the black woodpecker and the Tokyo bitterling are introduced as an endangered species in two textbooks, the killifish in three, the Amami rabbit in four, and the Iriomote wildcat and the Okinawa rail in six each (Appendix 2). It is desirable that further research on the development of teaching materials like them will be conducted in the future and that the results will be used in biology textbooks.
Species that are endangered outside of Japan are not covered in most textbooks in relation to biodiversity and its conservation, perhaps because the topic is outside the scope of Basic Biology courses. Among the overseas organisms found in the unit "Diversity of Organisms, and Ecosystems" in textbooks, 24 species or taxa are listed on the IUCN Red List (Appendix 3), most of which are presented as representatives of the world's biomes. Therefore, they are not stated as endangered species, but it would have been better to at least state that. More than five textbooks use the Asian elephant, the European rabbit, the lion, and the reindeer for explaining the biome in which each of them habits. Possibly, they are familiar animals among upper secondary students. However, some of the other endangered species seem to be unfamiliar to the students. Is it appropriate to use such a rare and endangered species as a representative of a certain biome? Although it is not related to the objectives of present study, when compiling a textbook, careful consideration should be given to what species should be the representative species of each biome.
Treatment of Alien Organisms in Current Basic Biology TextbooksHiga (2019) reported that several topics related to alien organisms were included in all previous Basic Biology textbooks which were used until the 2021 academic year. According to him, among the ten Basic Biology textbooks, nine explained alien organisms, seven discussed the history of their introduction or the route of invasion, ten explained their adverse impacts, eight described measures against them in Japan, and eight presented laws and regulations related to them.
As mentioned above, the current USS-NCS does not list the term "alien organisms," but its Guidelines recommend including the introduction of alien species as an example of anthropogenic disturbance (MEXT, 2021, p. 125). Following the recommendation of the USS-NCS Guidelines, and as already pointed out (Higa, 2024; Katayama and Nakamichi, 2024), all Basic Biology textbooks include the term alien organisms (or alien species) in the main text, list it in their indexes, and treat it as a key term (Table 3). All textbooks explain alien species and their adverse effects, nine explain the countermeasures against invasive alien species in Japan, and eight introduce the IAS Act and the DIAS under the Act. Up to this point, their contents are almost the same as previous Basic Biology textbooks, but while seven previous Basic Biology textbooks provided specific examples explaining the history of the introduction of invasive species and their routes of invasion (Higa, 2019), only four current textbooks include this topic (Table 3).
There is an issue with the use of terms related to alien organisms. The category DIAS is included in the category of invasive alien species, which are included in the category of alien species. However, among the ten textbooks, some only use two terms DIAS and alien species (Table 3). If students are to conduct an inquiry activity by using technique such as text mining and the creation of concept maps (Mori, et al., 2017), then it is essential that the terminology is clearly and consistently applied.
Some of the invasive alien species listed in the textbooks are not necessarily exemplified as DIAS or species on the LIST. However, there was almost no difference between the average number of invasive alien species appearing in the textbooks and the average number of species clearly stated as DIAS. This is because, unlike the case of endangered native species (Table 2), most DIASs are described as such in all textbooks except for Textbooks #1 and #2 (Table 4). In terms of selecting invasive alien species, most textbooks seem to give priority to DIAS (Appendix 4). Even in this case, it is of course desirable to choose a species with which students are familiar. It is also desirable not to simply introduce the species with a photo, but to give some more information, such as its invention route, specific damage, and countermeasures, so that students can understand why the species is being used as an example in the textbook.
As mentioned in the INTRODUCTION, a considerable number of studies have been conducted so far on using alien organisms as teaching materials for biodiversity conservation in biology education at the secondary school level. Of these alien species, only largemouth bass, the bluegill, the Western mosquitofish, the signal crayfish, and the red swamp crayfish are included in current Basic Biology textbooks (Appendix 4). However, since the species specified as DIAS are prohibited from being kept or transferred without permission in Japan (MOE, 2014), it becomes very difficult to capture them, breed them at schools, and use live specimens as materials for experiments or dissection, etc. Although these organisms can be used for studying their ecology in their settled habitat (Kurabayashi et al., 2021) and their distribution (Suzue, 2007; Shimabe and Imai, 2021), students can only learn about them in the classroom through photographs, published research reports, and other sources.
According to Doi (2020), in Japan, the red swamp crayfish was encouraged to be kept as a pet at elementary schools and was included in many Life Studies textbooks for first and second graders, with some textbooks even encouraging the release of the animal into the wild after being used. However, elementary school textbooks compiled and published after 2015, when this animal was designated as an "alien species that require urgent measures (KT)" on the LIST, have not treated it as a captive animal. The same as this animal species, the red-eared slider turtle was also included in the LIST in 2015. Kato (2018) conducted a survey on the keeping of red-eared slider turtles in schools in Shizuoka Prefecture during the period of 2015-2016, and reported that among the 733 schools that responded, 45 were keeping 86 red-eared slider turtles. In 2023, both species were designated as "conditionally designated alien species", meaning they cannot be imported, sold, distributed, or released into the wild without permission, but individuals currently being kept will be able to continue raising (MOE, 2023, see website list). So MEXT issued a notice to institutions, which manage and operate schools, to take sufficient care when handling the red swamp crayfish and the red-eared sliders turtle in schools so as not to deleteriously affect local natural environments and ecosystems (MEXT, 2023).
Other invasive alien species and taxa on the LIST also require careful handling; the MOE has asked invasive alien species on the LIST not to be introduced, released and spread (MOE, 2015b). However, although the Brazilian elodea is included in the LIST as an "invasive alien species that requires priority measures (JT, Appendix 4)", it is included in Basic Biology textbooks without any warning and is being used as experimental material in upper secondary school biology classes. Therefore, this plant is kept in many upper secondary school laboratories, but many biology teachers wonder if they are aware that this plant is on the LIST and must be handled with care (This plant, along with the common water hyacinth (JT), is still sold in many pet stores in Japan). Xenopus laevis (African clawed frog) is also in the LIST and designated as "alien species requiring comprehensive measures (ST)", but it also is included in Basic Biology textbooks without any warning, and it seems to be treated the same as the Brazilian elodea in many schools.
On the other hand, the ragweed and the Sumatran fleabane mentioned in Textbook #1 as alien species had been designated as "alien species that require control measures" under the IAS Act, but this designation was revoked when the LIST was compiled and published in 2015 (MOE, 2015a, p. 4), and they are no longer included in the LIST (MOE, 2015b).
The number of invasive alien species designated under the IAS Act and other laws is increasing yearly, and the classifications to which they belong are also changing or, as in the case of the ragweed and the Sumatran fleabane, the designation may be revoked. The treatment of invasive alien species in textbooks and biology lessons needs to change accordingly. The same goes for endangered species. Because compiling and revising textbooks takes a considerable amount of time, biology teachers are required to try to obtain the latest information on invasive alien species and endangered species rather than relying solely on textbooks.
As stated in Textbook #4, alien organisms are not necessarily invasive and do not necessarily give adverse effects on native ecosystems they settled or on human beings. However, since some alien animals, such as the raccoon which was raised as pets (MOE, 2016, p. 8), and alien plants, such as the lance-leaf tickseed which was cultivated in flower beds (MOE, 2013), were released or escaped and became invasive alien organisms, students need to learn that proper handling alien organisms is very important for the conservation of native ecosystems.
Treatment of Domestic Alien Species in Current Basic Biology TextbooksMost textbooks explain that alien species (GAIRAI-SHU in Japanese) are organisms that have been brought from other regions by humans and have become established in areas where they were not originally distributed. However, most of these textbooks do not point out that the term "other regions" includes other areas in Japan. In recent years, some domestic alien species have caused problems in Japan, such as adversely affecting ecosystems into which they have invaded, causing genetic disturbance to local population and destroying vegetation (MOE, 2015a). Therefore, the LIST has included 20 animal species and ten plant species as domestic alien species that require measures (MOE, 2015b). Since most students are likely to interpret the word GAIRAI as foreign or overseas and cannot imagine domestic alien species, it is desirable for Basic Biology classes to mention this topic briefly. Doi and Hayashi (2015) reported that eight domestic alien species are found in three Basic Biology textbooks published in 2012 that they surveyed. However, Sakuraba et al. (2013) conducted a similar textbook survey that included the same textbooks earlier but did not report on the occurrence of domestic alien species at all, so it is unclear whether the eight species identified by Doi and Hayashi (2015) were presented as examples of domestic alien species in these textbooks. For the current Basic Biology textbooks, only three mention domestic alien organisms and their adverse effects. This is thought to be because there has been little research, except for Yamanoi et al. (2016b) and Sato et al. (2024), to date on introducing domestic alien species into school biology education. It is hoped that many research projects will be conducted to develop teaching materials on domestic alien species, and that the results will arouse students' interest. As an example, the HONMOROKO, an endemic species of Lake Biwa, the largest lake in Japan, which has been designated an endangered species (MOE, 2020) likely due to the invention of the alien predator, the bluegill (Shiga Prefecture, undated). However, the fish has been introduced into other lakes where it has become an invasive species (NIES, undated, see website list).
Treatment of Japanese Native Species that Have Become Invasive Alien Species Overseas in Current Basic Biology TextbooksThe problem of invasive alien organisms is not specific in Japan. But only two textbooks cover this issue, perhaps because the topic is outside the scope of Basic Biology courses. To prevent students from misunderstanding the word "alien species," it is advisable to mention native Japanese species that have spread overseas. Sakuraba et al. (2013) reported two Basic Biology textbooks published in 2012 dealt with this issue, both of which introduced the kudzu and Undaria pinnatifida (wakame), and one further introduced Acanthogobius flavimanus (yellow goby), Asterias amurensis (Northern Pacific sea star), Fallopia japonica (Japanese knotweed) and the Japanese silver grass. Among these organisms, the kudzu, the wakame, the Japanese knotweed and the Northern Pacific sea star have been listed on the 100 of the World’s Worst Invasive Alien Species (ISSG List; Lowe et al., 2000).
The kudzu and the Japanese silver grass are still used in current Basic Biology textbooks as examples of invasive species from Japan. The kudzu seems to be a good example of the invasive alien species in the USA because it was “introduced into the United States at the 1876 Centennial Exposition in Philadelphia (Forseth and Innis, 2004, p. 401).” The Japanese knotweed, along with the Japanese silver grass, is introduced in Basic Biology textbooks as a pioneer species of primary succession, but since this plant species is included in the ISSG List mentioned above, it seems to be a better example than the Japanese silver grass. Another good example is the wakame, a popular edible seaweed in Japan that is considered “one of the world’s worst invaders (South et al., 2017).”
Textbook #3 mentions that “carp” from Japan has become an invasive alien organism in the USA, but this description seems to be a misquotation. Cyprinus carpio (common carp) is included in the ISSG List and is one of the worst invasive carp species (Asian carp) in that country. However, it was introduced from Europe, not Japan (Koel et al., 2000, see website list). Furthermore, “in the United States, four species of non-native carp – bighead, silver, black and grass carp – are collectively called invasive carp” (Invasive Carp Regional Coordinating Committee, 2022). Therefore, the invasive carp in the USA refers exclusively to the following four fish species native to Asia: Hypophthalmichthys nobilis (bighead carp), H. molitrix (silver carp), Mylopharyngodon piceus (black carp), and Ctenopharyngodon idella (grass carp), with the first two species native to China, being of particular concern (New York Invasive Species Information, 2019, see website list). Instead of carp, Popillia japonica (Japanese beetle) may be a good example of a Japanese native animal species that has become an invasive species in the USA, because it “has become the most widespread and destructive insect pest of turf, landscapes, and nursery crops in the eastern United States (Potter and Held, 2002, p. 175).”
In addition to the topic of Japanese native species becoming invasive species in other countries, students will also be interested to learn about species that are endangered in their native habitats, but have become invasive species in other countries where they have been introduced, altering native ecosystems and causing social problems. For example, the European rabbit, in its native habitat (in the Iberian Peninsula), is classified as EN (endangered) on the IUCN Red List (IUCN, undated, see website list), but this species is included in the ISSG List and has become one of the worst pests in Australia where it was introduced (The National Museum of Australia, undated, see website list).
In this study I investigated the current Japanese USS-NCS, its Guidelines and currently used Basic Biology textbooks to find out how native organisms and alien organisms are treated in relation to biodiversity and its conservation in Basic Biology courses at Japanese upper secondary schools. The USS-NCS Guidelines recommend that, in Basic Biology course, the introduction of alien species be explained as an example of anthropogenic disturbances, citing an invasive alien species. However, regarding native organisms, it is only stated that they are being affected by introduced alien species, and there is no mention of endangered native species. Most of the Basic Biology textbooks surveyed included nearly all key terms related to native and alien organisms, but some textbooks were missing important concepts or the definitions of key terms or provided incomplete explanations of key terms.
Extinct and endangered species native to Japan listed in the sections related to biodiversity and its conservation of these textbooks were 71 (55 animals, 15 plants and one protist), although some of them are not clearly indicated as endangered. There was almost no mention of extinct or endangered species overseas. Invasive alien species that require measures such as DIAS listed in these textbooks were 52 species (38 animals and 14 plants), although some of them also are not clearly stated as they are such species. The number of extinct and endangered species native to Japan and invasive alien species in Japan listed varied greatly between textbooks. When using textbooks with fewer examples of endangered and invasive alien species, teachers need to provide additional information to students. Very few textbooks listed domestic alien species and Japanese native species that have become invasive overseas. These topics, however, are indispensable for students to understand what invasive alien species are.
In biology education at the upper secondary level, endangered species and their protection are one of the topics that students should learn. However, when learning about endangered species, students are expected not only to consider the protection of a particular endangered species, but also to think about ways to reduce the number of species facing extinction. Furthermore, from the perspective of biodiversity conservation, it is also necessary to think about ways to enhance biodiversity. This also leads to the conservation of natural environment, i.e., ecosystem conservation, which is one of the goals of the curriculum guidelines as described below. To this end, it is important for teachers to have students think about how to conserve the habitats of native species, including endangered species, in their surroundings, using examples such as SATOYAMA and wetlands, which are rich in biodiversity.
The curriculum guidelines call for students to “understand the relationship between ecosystem balance and human disturbance, and recognize the importance of ecosystem conservation (MEXT, 2021, p.125)”. An example of anthropogenic disturbance is the negative impact of artificially introduced alien species on native species, but students are not only required to consider measures to mitigate the negative impact of invasive alien species. Anthropogenic disturbance is not just the introduction of invasive species into a specific native ecosystem. Humans have anthropogenic impacts on ecosystems around the world through a variety of activities, including deforestation, land development, waste disposal, air and water pollution, and greenhouse gas emissions. These global environmental issues have led to a decline in biodiversity in many parts of the world, and Conservation International has designated these places as Biodiversity Hotspots (Conservation International, undated, see website list). Students must consider not only how to properly conserve the habitats of endangered native species, but also how to address various environmental issues to conserve global biodiversity.
I would like to express my sincere gratitude to Professor Robert Wallis of Federation University, Australia, who read the original paper and provided valuable suggestions for improving it. I also am grateful to my colleagues Dr. Hideo Kitano and Ms. Teiko Nakamichi, who provided useful advice during the preparation of the paper.
In the Basic Biology textbooks surveyed, both -SEIBUTSU (organism) and -SHU (species) are used, and in some cases the term -SHU is not used in its biological sense, i.e., indicating each species. This paper uses the term "organism" when not referring to each biological species.
A native species is generally defined as, for example, “a species that is within its known natural range, and occurs naturally in a given area or habitat, as opposed to an introduced species or invasive species; it is also known as endemic species or indigenous species (Oxford Reference, undated, see the Website list).” However, because synonymous Japanese terms for native organisms appear in the textbooks surveyed, this paper uses different English terms to discriminate them (Table A-1), and their definitions are as follows: a native species is a species that has been in a particular area for a long time and still inhabits there today, rather than being introduced from elsewhere, i.e., the term native species is roughly the same as primeval species. However, in Japan, forests that have grown naturally without human intervention are called GENSEI-RIN (primeval forests), and so a primeval species refers to a species living in natural environments (wild nature) that have had little or no human influence. An endemic species refers to “a species or subspecies whose distribution is restricted to a specific area, which can be considered at various levels such as country, prefecture, or region (EIC Net, undated, see website list).”
| Japanese terms | English terms |
|---|---|
| SHU | species |
| SEIBUTSU | organism |
| ZAIRAI-NO (ZAIRAI-SHU) | native (native species) |
| KOYU-NO (KOYU-SHU) | endemic (endemic species) |
| GENSEI-NO (GENSEI-SHU) | primeval (primeval species) |
| KISHOH (KISHO-SHU) | rare (rare species) |
| ZETSUMETSU-KIGU-SHU | endangered species |
| GAIRAI-NO (GAIRAI-SHU) | alien (alien species) |
| GAIRAI-SEIBUTSU HOU | Act on the Prevention of Adverse Ecological Impacts Caused by Designated Invasive Alien Species (Invasive Alien Species Act / IAS Act) |
| SHINRYAKUTEKI GAIRAI-SHU | invasive alien species |
| TOKUTEI GAIRAI-SHU | designated invasive alien species (DIAS) |
An endangered species refers to a species or subspecies listed on the MOE Red List 2020 (MOE, 2020). The term also refers to a species or subspecies listed on the IUCN Red List (IUCN, undated, see website List).
An alien species refers to a species which has been introduced artificially, whether intentionally or not, into non-native habitats, in other words, an introduced species, an adventive species or an exotic species. The term invasive species is also often used to refer to non-native species, but to avoid confusion with invasive alien species defined below, this paper uses the word “invasive” only for invasive alien species. An invasive alien species refers to “an alien species which threatens biological diversity by bringing an adverse impact which could not arise under natural conditions (MOE, 2004a).” A designated invasive alien species (abbreviated as DIAS) refers to a species designated by Japanese government under the IAS Act. Since invasive alien organisms including DIAS are thought “to have adverse effects on ecosystems, human life and health, agriculture, forestry, fisheries, etc. (MOE, 2004b, 2014),” they have been including in the List of Alien Species that May Cause Damage to Japan's Ecosystems (abbreviated as the LIST). The LIST was compiled in 2015 by the MOE and the Ministry of Agriculture, Forestry and Fisheries to serve for countermeasures of invasive alien organisms following the National Biodiversity Strategy 2012-2020, which was approved by the Cabinet in September 2012. The LIST includes five categories of invasive alien species (Table A-2) which are “not only designated invasive alien species under the IAS Act, but also invasive alien organisms that cause or are likely to cause damage to Japan's ecosystems, etc. (MOE, 2015a).”
The classification “alien species of domestic origin (MOE, 2015a, p. 3),” is not included in the LIST categories, but the LIST does list species that fall into this category. An alien species of domestic origin or domestic alien species (Table A-2) refers to “a species that have a natural distribution range in Japan but have been introduced into other parts of the country beyond their natural distribution range (MOE, undated, see website list).”
| Japanese terms | English terms |
|---|---|
| SEITAIKEI HIGAI-BOUSHI GAIRAI-SHU List | the List of Alien Species that May Cause Damage to Japan's Ecosystems (LIST) |
| SHNNYU YOBOU GAIRAI-SHU | alien species to be prevented from entering (SY) |
| TEICHAKU YOBOU GAIRAI-SHU | alien species requiring measures to prevent establishment (TY) |
| KINKYU TAISAKU GAIRAI-SHU | alien species requiring emergency measures (KT) |
| JUTEN TAISAKU GAIRAI-SHU | alien species requiring priority measures (JT) |
| SOGO TAISAKU GAIRAI-SHU | alien species requiring comprehensive measures (ST) |
| KOKUNA YURAI NO GAIRAI-SHU (KOKUNAI GAIRAI-SHU) | alien species of domestic origin (domestic alien species) |
| Species | MOE Category* | Number of textbooks listing** | |
|---|---|---|---|
| Mammals | Canis lupus hodophilax (Japanese wolf) | EX | 2 (2) |
| Lutra lutra nippon / Lutra lutra whiteleyi (Japanese otter) ◆ | EX | 1 (1) | |
| Dugong dugon (dugong) | CR | 3 (3) | |
| Enhydra lutris (sea otter) | CR | 10 (0) | |
| Prionailurus bengalensis euptilurus (Tsushima wildcat) | CR | 5 (5) | |
| Prionailurus bengalensis iriomotensis (Iriomote wildcat) ◆ | CR | 5 (4) | |
| Pteropus dasymallus daitoensis (Daito flying fox) | CR | 1 (1) | |
| Zalophus japonicus (Japanese sea lion) | CR | 1 (1) | |
| Pentalagus furnessi) (Amami rabbit) ◆ | EN | 6 (6) | |
| Sorex minutissimus hawkeri (Hawker's least shrew) | VU | 1 (1) | |
| Mustela erminea (stoat) | NT | 4 (4) | |
| Phoca vitulina (harbour seal) | NT | 1 (0) | |
| Capricornis crispus (Japanese serow) ◆ | LP*** | 4 (1) | |
| Birds | Ciconia boyciana (Japanese white stork) | CR | 3 (3) |
| Gallirallus okinawae (Okinawa rail) | CR | 6 (6) | |
| Ketupa blakistoni blakistoni (Blakiston's fish-owl) | CR | 1 (1) | |
| Nipponia nippon (Japanese crested ibis) ◆ | CR | 6 (6) | |
| Aquila chrysaetos japonica (golden eagle) | EN | 1 (1) | |
| Lagopus muta japonica (rock ptarmigan) ◆ | EN | 7 (5) | |
| Butastur indicus (grey-faced buzzard) | VU | 2(0) | |
| Charadrius alexandrinus dealbatus (Kentish plover) | VU | 1 (1) | |
| Dryocopus martius martius (black woodpecker) | VU | 2 (1) | |
| Falco peregrinus japonensis (Japanese peregrine falcon) | VU | 1 (1) | |
| Grus japonensis (red-crowned crane) ◆ | VU | 2 (2) | |
| Phoebastria albatrus (short-tailed albatross) | VU | 5 (5) | |
| Sterna albifrons sinensis (little tern) | VU | 2 (0) | |
| Accipiter gentilis fujiyamae (Northern goshawk) | NT | 1 (0) | |
| Pandion haliaetus haliaetus (osprey) | NT | 2 (0) | |
| Reptiles | Caretta caretta (logger head turtle) | EN | 4 (4) |
| Eretmochelys imbricata (Hawksbill turtle) | EN | 1 (1) | |
| Chelonia mydas mydas (green sea turtle) | VU | 3 (2) | |
| Amphibians | Hynobius abei (Abe's salamander) | CR | 2 (2) |
| Pelophylax porosus brevipodus (Nagoya daruma frog) | EN | 1 (1) | |
| Andrias japonicus (Japanese giant salamander) ◆ | VU | 3 (3) | |
| Hynobius nebulosus (clouded salamander) | VU | 1 (1) | |
| Hynobius tokyoensis (Tokyo salamander) | VU | 1 (1) | |
| Fish | Oncorhynchus kawamurae (black kokanee) | EW | 1 (1) |
| Gnathopogon caerulescens (HONMOROKO) | CR | 2 (0) | |
| Pseudorasbora pumila (SHINAI top-mouth gudgeon) | CR | 1 (1) | |
| Tanakia tanago (Tokyo bitterling) | CR | 3 (2) | |
| Anguilla japonica (Japanese eel) | EN | 3 (3) | |
| Lefua echigonia (HOTOKE loach) | EN | 1 (1) | |
| Oryzias latipes / Oryzias sakaizumii (killifish) | VU | 5 (3) | |
| Gymnogobius castaneus (JUZUKAKE goby) | NT | 2 (0) | |
| Sarcocheilichthys variegatus variegatus (KAWAHIGAI) | NT | 2 (0) | |
| Insects | Libellula Angelina (BEKKO dragonfly) | CR | 2 (2) |
| Luciola owadai (Kumejima firefly) | CR | 1 (1) | |
| Melitaea scotosia (HYOMON-MODOKI) | CR | 2 (2) | |
| Cheirotonus jambar (Yanbaru long-armed scarab beetle) | EN | 2 (2) | |
| Cybister chinensis (GENGORO water beetle) | VU | 5 (4) | |
| Dorcus hopei binodulosus (giant stag beetle) | VU | 1 (0) | |
| Kirkaldyia deyrolli (giant water bug) | VU | 2 (0) | |
| Luehdorfia japonica (Japanese Luehdorfia) | VU | 2 (0) | |
| Phengaris arionides takamukui (greater large blue) | NT | 1 (1) | |
| Sasakia charonda charonda (great purple emperor) | NT | 2 (0) | |
| Plants | Viola stoloniflora (ORIDZURU violet) | EW | 1 (1) |
| Callianthemum miyabeanum (Hidaka-so) | CR | 1 (1) | |
| Gentiana aquatica (HINA gentian) | CR | 1 (1) | |
| Persicaria japonica var. taitoinsularis (DAITO SAKURATADE) | CR | 1 (1) | |
| Polemonium kiushianum (HANASHINOBU) | CR | 2 (2) | |
| Rhododendron boninense (MUNIN azalea) | CR | 3 (3) | |
| Cypripedium marcanthos var. rebunense (Rebun Cypripedium) | EN | 1 (1) | |
| Oxytropis megalantha (REBUN-SO) | EN | 1 (1) | |
| Stellaria humifusa (saltmarsh starwort) | EN | 1 (1) | |
| Echinops setifer (HIGOTAI) | VU | 1 (1) | |
| Marsilea quadrifolia (DENJI-SO) | VU | 1 (1) | |
| Sciaphila nana (HONGO-SO) | VU | 2 (2) | |
| Xanthium strumarium (common cocklebur) | VU | 1 (0) | |
| Eupatorium japonicum (thoroughwort) | NT | 2 (1) | |
| Monochoria korsakowii (MIZUAOI) | NT | 1 (1) | |
| Protist | Aegagropila linnaei (MARIMO) ◆ | CR/EN | 2 (2) |
| Species / Taxon | IUCN Category* | Number of textbooks listing** | |
|---|---|---|---|
| Mammals | Pongo spp. (orangutans) | CR | 7 (3) |
| Elephas maximus (Asian elephant) | EN | 6 | |
| Equus ferus przewalskii (Przewalski's wild horse) | EN | 3 | |
| Inia geoffrensis (Amazon river-dolphin) | EN | 1 | |
| Oryctolagus cuniculus (European rabbit) | EN | 6 | |
| Panthera tigris altaica (Siberian tiger) | EN | 3 | |
| P anthera tigris tigris (Bengal tiger) | EN | 2 | |
| Pan troglodytes (chimpanzee) | EN | 1 | |
| Rhinopithecus roxellana (golden snub-nosed monkey) | EN | 1 | |
| Acinonyx jubatus (cheetah) | VU | 2 | |
| Ailuropoda melanoleuca (giant panda) | VU | 1 | |
| Aonyx cinerea (Asian small-clawed otter) | VU | 1 | |
| Bison bison (American bison) | VU | 3 | |
| Giraffa camelopardalis (giraffe) | VU | 3 | |
| Panthera leo (lion) | VU | 5 | |
| Rangifer tarandus (reindeer) | VU | 7 | |
| Ursus maritimus (polar bear) | VU | 3 | |
| Ornithorhynchus anatinus (platypus) | NT | 1 | |
| Panthera onca (jaguar) | NT | 3 | |
| Birds | Ectopistes migratorius (passenger pigeon) | EX | 2 (2) |
| Neophron percnopterus (Egyptian vulture) | EN | 1 | |
| Spheniscus humboldti (Humboldt penguin) | VU | 1 | |
| Reptiles | Sea turtles | CR - VU | 1 |
| Plants | Selaginella lepidophylla (stone flower) | NT | 1 |
| Organisms | Category in the IAS Act or the LIST*** | Number of textbooks listing**** | |
|---|---|---|---|
| Mammals | Callosciurus erythraeus (Taiwan squirrel) | DIAS | 1 (1) |
| Erinaceus spp. (hedgehogs) | DIAS | 1 (1) | |
| Herpestes auropunctata (small Indian mongoose) ***** | DIAS | 8 (4) | |
| Macaca cyclopis (Taiwan macaque) | DIAS | 3 (3) | |
| Muntiacus reevesi (Reeves's muntjac) | DIAS | 1 (1) | |
| Mustela vison (American mink) | DIAS | 1 (1) | |
| Myocastor coypus (nutria) | DIAS | 1 (1) | |
| Ondatra zibethicus (muskrat) | DIAS | 1 (1) | |
| Procyon lotor (raccoon) | DIAS | 8 (7) | |
| Trichosurus vulpecula (brushtail possum) | DIAS | 1 (1) | |
| Birds | Garrulax canorus (laughing thrushes) | DIAS | 3 (3) |
| Leiothrix lutea (red-billed mesia) | DIAS | 1 (1) | |
| Pycnonotus cafer (red-vented bulbul) | DIAS | 1 (1) | |
| Reptiles | Anolis carolinensis (green anole) | DIAS | 5 (3) |
| Chelydra serpentina (snapping turtle) | DIAS | 4 (4) | |
| Protobothrops mucrosquamatus (Taiwan pit vivers) | DIAS | 2 (2) | |
| Amphibians | Bufo cognatus (Great Plains toad) | DIAS | 1 (1) |
| Bufo marinus (cane toad) | DIAS | 1 (1) | |
| Eleutherodactylus coqui (Puerto Rican coquí) | DIAS | 1 (1) | |
| Rana catesbeiana (bullfrog) | DIAS | 4 (3) | |
| Fish | Atractosteus spatula (alligator gar) | DIAS | 1 (1) |
| Esox lucius (northern pike) | DIAS | 1 (1) | |
| Gambusia affinis (Western mosquito fish) | DIAS | 1 (0) | |
| Ictalurus punctatus (channel catfish) | DIAS | 1 (1) | |
| Lepomis macrochirus (bluegill) | DIAS | 6 (2) | |
| Micropterus dolomieu (smallmouth bass) | DIAS | 1 (1) | |
| Micropterus salmoides (largemouth bass) | DIAS | 10 (4) | |
| Siniperca chuatsi (Mandarin fish) | DIAS | 1 (1) | |
| Insects | Bombus terrestris (large earth bumblebee) | DIAS | 3 (3) |
| Linepithema humile (Argentine ant) | DIAS | 1 (1) | |
| Propomacrus spp. (Propomacrus beetles) | DIAS | 1 (1) | |
| Solenopsis invicta (red imported fire ant) | DIAS | 5 (5) | |
| Crustaceans | Pacifastacus leniusculus (signal crayfish) | DIAS | 2 (2) |
| Procambarus clarkii (red swamp crayfish) | KT | 1 (0) | |
| Spiders | Latrodectus hasseltii (red-back widow spider) | DIAS | 2 (2) |
| Shellfish | Dreissena polymorpha (zebra mussel) | DIAS | 1 (1) |
| Limnoperna fortunei (golden mussel) | DIAS | 1 (1) | |
| Achatina fulica (giant African snail) | JT | 1 (0) | |
| Plants | Coreopsis lanceolata (lance-leaf tickseed) | DIAS | 3 (3) |
| Gymnocoronis spilanthoides (Senegal tea plant) | DIAS | 1 (1) | |
| Myriophyllum aquaticum (parrot feather) | DIAS | 1 (1) | |
| Pistia stratiotes (water lettuce) | DIAS | 4 (4) | |
| Rudbeckia laciniata (cut-leaf coneflower) | DIAS | 2 (2) | |
| Sicyos angulatus (bur cucumber) | DIAS | 4 (4) | |
| Veronica anagallis-aquatica (water speedwell) | DIAS | 1 (1) | |
| Egeria densa (Brazilian elodea) | JT | X | |
| Eichhornia crassipes (common water hyacinth) | JT | X | |
| Taraxacum officinale (common dandelion) | JT | 1 (0) | |
| Oenothera laciniata (cut-leaf evening primrose) | JT | 1 (1) | |
| Solidago altissima (tall goldenrod) | JT | 1 (0) | |
| Erigeron annuus (annual fleabane) | ST | X | |
| Xanthium canadense (oriental cocklebur) | ST | 1 (0) | |
