2019 ᖺ࡟࠾ࡅࡿすஅᓥࡢ㫽㢮┦ᕝୖ࿴ே 1ࠊᑠᒣ⏣భ㍜ 2

Avifauna of Nishinoshima Island, the Ogasawara Islands, in 2019

Kazuto KAWAKAMI1*& Yusuke OYAMADA2
1. ᳃ᯘ⥲ྜ◊✲ᡤ㸦ࠛ305-8687 Ⲉᇛ┴ࡘࡃࡤᕷᯇࡢ㔛 1㸧
Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 3058687, Japan2. ⮬↛⎔ቃ◊✲ࢭࣥࢱ࣮㸦ࠛ130-8606 ᮾி㒔ቚ⏣༊Ụᮾᶫ 3-3-7㸧
Japan Wildlife Research Center, 3-3-7 Kotobashi, Sumida, Tokyo 130-8606, Japan.
* kazzto@ffpri.affrc.go.jp (author for correspondence)せ᪨ 2013 ᖺ࠿ࡽࡢᄇⅆ࡛ᪧᓥࡢ࡯࡜ࢇ࡝ࡀ⁐ᒾ࡟そࢃࢀࡓすஅᓥ࡟࠾࠸࡚ࠊ㫽㢮┦ࡢ⌧≧࡜ኚ໬ࢆ᫂ࡽ࠿࡟ࡍࡿࡓࡵࠊ2019 ᖺ 9 ᭶ 3 ᪥ࠥ5 ᪥࡟ୖ㝣ࡋ࡚ㄪᰝࢆ⾜ࡗࡓࠋࡑࡢ⤖ᯝࠊᪧᓥ࠾ࡼࡧࡑࡢ࿘㎶࡛࢝ࢶ࢜ࢻࣜࠊ࢔࢜ࢶࣛ࢝ࢶ࢜ࢻࣜࠊ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜࠊࢡࣟ࢔ࢪࢧࢩࠊ࢜࢜࢔ࢪࢧࢩࡢ㞮ࡸ༸࡞࡝⦾Ṫࡢドᣐࡀᚓࡽࢀࡓࠋ≉࡟࢝ࢶ࢜ࢻࣜࡣᪧᓥ࿘㎶ࡔࡅ࡛⣙ 400 ಶయࡢ㞮ࡀ☜ㄆࡉࢀࠊᄇⅆ࡟ࡼࡿ᧠஘ᚋ࡟⦾Ṫ㞟ᅋࡀᅇ᚟ࡋࠊ⁐ᒾୖࡸᾏᓊ࡞࡝᪂ࡓ࡞㝣ᆅ࡟㐍ฟࡋ࡚࠸ࡿࡇ࡜ࡀ᫂ࡽ࠿࡟࡞ࡗࡓࠋ࢝ࢶ࢜ࢻࣜࡢ⦾Ṫᮇࡀᑠ➟ཎࡢ௚ᆅᇦ࡟ẚ࡭࡚㛗ᮇ໬ࡋ࡚࠸ࡓࡀࠊࡇࢀࡣ㧗ᐦᗘ໬ࡀཎᅉ࠿ࡶࡋࢀ࡞࠸ࠋᾏ㫽ࡣᰤ㣴ሷ౪⤥ࡸ✀Ꮚᩓᕸ࡞࡝ከࡃࡢ⏕ែ⣔ᶵ⬟ࢆᣢࡘࡓࡵࠊ᪂ࡓ࡞㝣ᆅ࡟⦾Ṫᆅࢆᣑ኱ࡍࡿࡇ࡜࡛⏕ែ⣔ࡢᡂ❧ࢆಁ㐍ࡍࡿྍ⬟ᛶࡀ࠶ࡿࠋ࣮࣮࢟࣡ࢻ ᾏ㫽ࠊᑠ➟ཎㅖᓥࠊ࢝ࢶ࢜ࢻࣜࠊ⏕ែ⣔ᶵ⬟ࠊಖ඲㸯㸬ࡣࡌࡵ࡟ すஅᓥࡣᑠ➟ཎㅖᓥࡢᏙ❧ࡋࡓ↓ேᓥ࡛ࠊ᭱ࡶ㏆࠸∗ᓥิᓥ࠿ࡽ⣙ 130km 㞳ࢀ࡚࠸ࡿࠋ௨๓ࡣᓥࡢ㠃✚ࡣ⣙ 7ha ࡔࡗࡓࡀࠊ1973 ᖺࡢ㏆ഐ࡛ࡢᾏᗏⅆᒣᄇⅆ࡟ࡼࡾ⣙− 79 −KD ࡟ᣑ኱ࡋࡓࠋࡑࡢᚋࠊ ᖺ  ᭶࠿ࡽ෌ࡧᾏᗏⅆᒣࡀᄇⅆࡋࠊ⁐ᒾ࡟ࡼࡾᪧすஅᓥࡢ 㸣௨ୖࡀ⁐ᒾࡢୗ࡟ᇙࡲࡗࡓࠋ ᖺ࡟ࡣᄇⅆࡀ୍᪦཰᮰ࡋࡓࡶࡢࡢࠊ
 ᖺ  ᭶ࠥ ᭶࠾ࡼࡧ  ᖺ  ᭶࡟ᄇⅆࡀ⏕ࡌࠊ㠃✚ࡣ᭱኱࡛ KDࠊᶆ㧗ࡣP ࡟㐩ࡋࡓࠋ ᖺ  ᭶࡟ࡣᪧすஅᓥ⏤᮶ࡢ㝣ᆅࡣᓥࡢす㒊࡟⣙ KD ࡀṧᏑࡋࠊࡑࡢ௚ࡢ㒊ศࡣ  ᖺࡢᄇⅆ௨ᚋ࡟࡛ࡁࡓ⁐ᒾࠊࢫࢥࣜ࢔ࡢሁ✚ࡋࡓᾏ὾ࠊⅆ○ୣ࡞࡝࡟ࡼࡿ᪂ࡓ࡞㝣ᆅ࡛ᵓᡂࡉࢀ࡚࠸ࡿ㸦ᅗ 㸧ࠋ すஅᓥ࡟ே㛫ࡢᐃఫグ㘓ࡣ࡞࠸ࡀࠊேⅭⓗ࡞ᙳ㡪ࡀ඲ࡃ࡞࠿ࡗࡓ࡜ࡣゝ࠼࡞࠸ࠋ᫂἞᫬௦࡟ࡣ⣙  ࣨ᭶࡟  ᅇ  ྡࡀᩘ᪥㛫⁫ᅾࡋࠊࢢ࢔ࣀࢆ᥇㞟ࡋ࡚࠸ࡓ࡜ࡉࢀ࡚࠸ࡿ㸦㟷ᮌ࣭ᑠᆏࠊ㸧ࠋ ᖺ  ᭶࡜  ᭶࡟ࡣᆅඖ⁺ᖌ࡟ࡼࡾ࢔࣍࢘ࢻࣜ3KRHEDVWULD DOEDWUXV ࡢ༸࠾ࡼࡧᡂ㫽ࡀ᥇㞟ࡉࢀࠊ㫽㢮Ꮫ⪅⢄ᒣᚨኴ㑻Ặ࡟ᥦ౪ࡉࢀࡓグ㘓ࡀ࠶ࡿ㸦$XVWLQ㸧ࠋୗᮧ㸦㸧ࡣࠕ㏆ᖺ⁺⯪ࡢ⨨ཤࡘࡓ㔝⊧ࡀ⶝ᘏࡋࠊஅ㸦ⴭ⪅ὀ㸸࢜࢜࢔ࢪࢧࢩ 6WHUQD EHUJLL ࡢࡇ࡜㸧ࢆᐖࡩࡶࡢࡀከ࠸࡜⪺ࡃࠖ࡜グ㘓ࡋ࡚࠸ࡿࠋࡲࡓࠊ ᖺ  ᭶  ᪥࡟⡿㌷ࡀ᧜ᙳࡋࡓ⯟✵෗┿࡟ࡣᓥࡢ໭㒊࡟╔㝣ࡲࡓࡣቒⴠࡋࡓࡽࡋ࠸⯟✵ᶵࡀぢࡽࢀࡿ㸦ᅜᅵᆅ⌮㝔 ᆅᅗ࣭✵୰෗┿㜀ぴࢧ࣮ࣅࢫKWWSVPDSSVJVLJRMS㸧ࠋ௨ୖࡢࡇ࡜࠿ࡽࠊ᫂἞࠿ࡽ᫛࿴ึᮇ࡟࠿ࡅすஅᓥࡢ⏕ែ⣔ࡣ୍ᐃࡢ᧠஘ࢆཷࡅ࡚࠸ࡓ࡜⪃࠼ࡽࢀࡿࠋ  ᖺࡢᄇⅆ௨๓࡟ࡣᓥ࡟ࡣ࢔࣍࢘ࢻࣜࠊ
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ࢩ $QRXV VWROLGXVࠊ࢜࢜࢔ࢪࢧࢩࠊࢭࢢࣟ࢔ࢪࢧࢩ 6W IXVFDWD ࡀ⦾Ṫࡋ࡚࠸ࡓ㸦⢄ᒣࠊ㸧ࠋࡇࡢ࠺ࡕ࢔࣍࢘ࢻࣜࡣᡓᚋࡢグ㘓ࡀ࡞ࡃᒁᡤ⤯⁛ࡋ࡚࠸ࡿࡀࠊࡇࢀᅗ  すஅᓥࡢᆅᅗࡣ⩚ẟ➼ࢆ┠ⓗ࡜ࡋࡓ㯮୸ࡣタ⨨ࡋࡓ࣮ࣟ࢞ࡢ఩⨨ࠋᆅᅗࡣᅜᅵᆅ⌮㝔࣭ᆅ⌮㝔ࢱ஘⋓࡟ࡼࡿ࡜⪃࠼ࡽࢀ࢖ࣝ࡟ࡼࡿ㸦௨ୗྠᵝ㸧ࡿ㸦&KLEDHWDO㸧ࠋ)LJ0DSRI1LVKLQRVKLPDࡲࡓࠊࢡࣟ࢔ࢩ࢔࣍࢘%ODFNFLUFOHVVKRZORFDWLRQVRIGDWDORJJHUV− 80 −ࢻࣜࡣ 1969 ᖺ࡟ࡣ 50ࠥ70 ಶయࡢᕢ❧ࡕ๓ࡢ㞮ࡀぢࡘ࠿ࡗ࡚࠸ࡿࡀ㸦ὸᾏࡽࠊ1970㸧ࠊ1973 ᖺᄇⅆ௨ᚋ࡟ࡣ☜ㄆࡉࢀ࡚࠾ࡽࡎ㸦Chiba et al., 2007㸧ࠊᄇⅆ࡟ࡼࡿ᧠஘࡛⦾Ṫ㞟ᅋࡀᾘ⁛ࡋࡓ࡜⪃࠼ࡽࢀࡿࠋ1981 ᖺ 1 ᭶࡟ࡣ࢔࢝࢜ࢿࢵࢱ࢖ࢳࣙ࢘ Phaethon
rubricauda ࡢႠᕢࡀグ㘓ࡉࢀ࡚࠸ࡿࡀ㸦಴⏣࣭㔠Ꮚࠊ1982㸧ࠊࡑࢀ௨እ࡟グ㘓ࡀ࡞࠸ࡓࡵഅⓎⓗ࡞Ⴀᕢ࡜⪃࠼ࡽࢀࡿ㸦ᕝୖ࡯࠿ࠊ2005㸧ࠋ1991 ᖺ࠿ࡽࡣ࢔࢜ࢶࣛ࢝ࢶ࢜
ࢻࣜ Su. dactylatra ࡀᐃ╔ࡋࠊ2004 ᖺ࡟ࡣ࣮࢜ࢫࢺ࣑ࣥ࢘ࢶࣂ࣓ Oceanodroma tristramiࡢ⦾Ṫࡀ᪂ࡓ࡟☜ㄆࡉࢀ࡚࠸ࡿ㸦༓ⴥࠊ ᕝୖ࡯࠿ࠊ2005㸧ࠋ㝣㫽ࡢ⦾Ṫࡣࡇࢀࡲ࡛࡟☜ㄆࡉࢀ࡚࠸࡞࠸ࡀࠊΏࡾ࡜⪃࠼ࡽࢀࡿᑡᩘࡢ㝣㫽ࡸ΅⚺㢮ࡢグ㘓ࡀ࠶ࡿ㸦ᕝୖ࡯࠿ࠊ2005㸧ࠋ 2013 ᖺࡢᄇⅆᚋࡣ 2016 ᖺ 10 ᭶࡟ୖ㝣ㄪᰝࡀ⾜ࢃࢀࠊ࢝ࢶ࢜ࢻࣜ࡜࢔࢜ࢶࣛ࢝ࢶ࢜ࢻࣜࡢ⦾Ṫࠊ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜࡢᕢ✰ࡀ☜ㄆࡉࢀ࡚࠸ࡿ㸦ᕝୖࠊ2017㸧ࠋࡋ࠿ࡋࠊࡑࡢᚋࡣⅆᒣᄇⅆ࡟ࡼࡿᙳ㡪࡛㫽㢮࡟㛵ࡍࡿୖ㝣ㄪᰝࡣ⾜ࢃࢀ࡚࠾ࡽࡎࠊすஅᓥ࡟࠾ࡅࡿ㏆ᖺࡢ㫽㢮ࡢ⏕ᜥ≧ἣࡣ୙᫂࡜࡞ࡗ࡚࠸ࡿࠋ すஅᓥ࡟ᙧᡂࡉࢀࡓ᪂ࡓ࡞㝣ᆅ࡟ࡣࠊᪧᓥṧᏑ㒊ࡢ⏕≀ࡢศᕸᣑ኱࠾ࡼࡧᓥእ࠿ࡽࡢ⏕≀ࡢ౵ධ࡟ࡼࡾࠊ᪂ࡓ࡞⏕ែ⣔ࡀᙧᡂࡉࢀ࡚࠸ࡃ࡜⪃࠼ࡽࢀࡿࠋ㐣ཤ࡟ࡣ࢖ࣥࢻࢿࢩ࢔ࡢࢡࣛ࢝ࢱ࢘ᓥࡸ࢔࢖ࢫࣛࣥࢻࡢࢫࣝࢶ࢙࢖ᓥ࡛ࡶ᪂ࡓ࡞㝣ᆅࡀฟ⌧ࡋࠊ⏕ែ⣔ࡢᡂ❧㐣⛬ࡀࣔࢽࢱࣜࣥࢢࡉࢀ࡚࠸ࡿࠋࡋ࠿ࡋࡇࢀࡽࡢᓥࡣ᭷ேᓥࡸ࣓
࢖ࣥࣛࣥࢻ࠿ࡽࡢ㊥㞳ࡀ 20km ௨ୗࡋ࠿࡞࠸ࡓࡵࠊ┤᥋࠾ࡼࡧ㛫᥋ࡢேⅭⓗᙳ㡪ࢆ⿕ࡾࡸࡍ࠸ࠋ୍᪉࡛すஅᓥࡣ㠀ᖖ࡟Ꮩ❧ࡋ࡚࠾ࡾேⅭⓗᙳ㡪ࡀᑠࡉࡃࠊཎ⏕≧ែ࡟㏆࠸⏕ែ⣔ᡂ❧ࣉࣟࢭࢫࡀಖᏑࡉࢀ࡚࠸ࡿ࡜ゝ࠼ࡿࠋࡇࡢࡼ࠺࡞⎔ቃࡣୡ⏺ⓗ࡟ぢ࡚ࡶ⛥᭷࡛࠶ࡾࠊᏛ⾡ⓗ౯್ࡀᴟࡵ࡚㧗࠸ᓥ࡛࠶ࡿࠋ 㫽㢮ࡣ㣕⾜࡟ࡼࡾ௚ࡢ㝣ᆅ࡜すஅᓥࠊᾏ࡜㝣ࢆࡘ࡞ࡄᛶ㉁ࢆᣢࡘࡓࡵࠊ⏕ែ⣔ࡢᡂ❧ࣉࣟࢭࢫ࡟኱ࡁ࡞㈉⊩ࢆࡍࡿ࡜⪃࠼ࡽࢀࡿࠋࡓࡔࡋࠊᄇⅆ࡟ࡼࡿすஅᓥࡢ㫽㢮┦ኚ໬ࡣࡇࢀࡲ࡛࡟ሗ࿌ࡉࢀ࡚࠸࡞࠸ࠋࡑࡇ࡛ᮏ◊✲࡛ࡣࠊすஅᓥࡢ㫽㢮┦ࡢ⌧≧࡜ኚ໬ࢆ᫂ࡽ࠿࡟ࡍࡿࡓࡵࠊ2019 ᖺ 9 ᭶ 3 ᪥ࠥ5 ᪥࡟ୖ㝣ㄪᰝࢆ⾜ࡗࡓࠋ㸰㸬᪉ἲ㸰−㸯㸬ᾏ㫽ࡢศᕸ すஅᓥ࡟࠾ࡅࡿᾏ㫽ࡢ⦾Ṫ≧ἣࢆ᫂ࡽ࠿࡟ࡍࡿࡓࡵࠊᪧᓥࠊ໭すྎᆅࠊすஅ὾ࠊ
༡す὾࡟࠾࠸࡚ྛ✀ᾏ㫽ࡢ༸ࠊ㞮ࠊᕢࡢ᥈⣴ࢆ⾜ࡗࡓࠋᪧᓥࡣᗈࡃⅆᒣ⅊࡟そࢃࢀ࡚࠸ࡿࡶࡢࡢࠊ࢜ࣄࢩࣂ Eleusine indicaࠊࢫ࣋ࣜࣄࣘ Portulaca oleraceaࠊ࢖ࢾࣅ࢚
Echinochloa crus-galli ࡢ 3 ✀ࡢ᳜≀ࡀ⏕⫱ࡋ࡚࠸ࡓ㸦ୖᲄ࡯࠿ࠊ2020㸧ࠋ໭すྎᆅࡣ2015 ᖺ࡟ὶฟࡋࡓ⁐ᒾୖ࡟ᙧᡂࡉࢀࡓᖹᆠᆅ࡛᳜≀ࡣㄆࡵࡽࢀ࡞࠿ࡗࡓࠋすஅ὾ࡣ2015 ᖺ௨ᚋ࡟ᙧᡂࡉࢀࡓ◁♟ࡢ὾࡛ࠊᪧᓥࡢ┤㏆࡟ࡢࡳ࢜ࣄࢩࣂ࡜ࢫ࣋ࣜࣄࣘࡢศ
ᕸࡀ☜ㄆࡉࢀࡓࠋ༡す὾ࡣ 2017 ᖺࡢ⁐ᒾὶฟ࡟ࡼࡾฟ⌧ࡋࡓ᪂ࡓ࡞◁♟ࡢ὾࡛࠶ࡿࠋࡇࢀࡽࡢㄪᰝᆅ࡛ࠊᆅୖႠᕢࡍࡿᾏ㫽࡟ࡘ࠸࡚ࡣࠊᕢࠊ㞮ࠊ༸ࡢ఩⨨ࢆྍ⬟࡞

− 81 −㝈ࡾグ㘓ࡋࡓࠋᆅ୰Ⴀᕢᛶࡢᾏ㫽࡟ࡘ࠸࡚ࡣᕢ✰ࡢ఩⨨ࢆグ㘓ࡍࡿ࡜࡜ࡶ࡟ࠊᕢෆ
ࡢ༸࠾ࡼࡧ㞮ࡢ᭷↓ࠊᡂ㫽ࡢ᭷↓ࢆ᪥୰࡟グ㘓ࡋࡓࠋᆅ୰Ⴀᕢᛶࡢᾏ㫽࡛ࡣ↓సⅭ࡟㑅ࢇࡔᕢࢆᑐ㇟࡟⦾Ṫ≧ἣࢆグ㘓ࡋࡓࠋグ㘓ࡣ 10 ᕢ༢఩࡛ 5 ᅇ⧞ࡾ㏉ࡋࡓࠋࡲࡓࠊUAV㸦Unmanned Aerial Vehicle㸧࡟ࡼࡾᓥࡢእ࿘඲ᇦࡢᾏᓊ㒊ࢆ㧗ᗘ 60m ࡛᧜ᙳࡋࠊᾏ㫽ࡢႠᕢࢆ᥈⣴ࡋࡓࠋ ㄪᰝᮇ㛫ࡀ୺࡞⦾Ṫᮇ࡟ヱᙜࡋ࡞࠸ᾏ㫽ࡢ⏕ᜥ≧ἣࢆ᫂ࡽ࠿࡟ࡍࡿࡓࡵࠊㄪᰝᆅ
ࢆ㋃ᰝࡋ࡞ࡀࡽほᐹࡉࢀࡓᾏ㫽ࢆ௵ព࡛グ㘓ࡋࡓࠋ࣑ࢬࢼࢠࢻࣜ⛉࠾ࡼࡧ࣑࢘ࢶࣂ࣓⛉ࡢ㫽ࡣኪ㛫࡟⦾Ṫᆅ࡟㣕᮶ࡍࡿࡓࡵࠊᪧᓥୖ࡛ኪ㛫ㄪᰝࢆ⾜࠸㫽㢮ࡢ✀࡜ಶయᩘࢆグ㘓ࡋࡓࠋࡲࡓࡇࢀࡽࡢᾏ㫽ࡣኪ㛫࡟✀≉␗ⓗ࡞ኌ࡛㬆ࡃࡓࡵࠊᪧᓥୖ࡟ IC ࣞࢥ࣮ࢲ࣮ࢆ⨨ࡁኪ㛫㘓㡢ࢆ⾜ࡗࡓࠋ࣑ࢬࢼࢠࢻࣜ⛉ࡢಶయࡢ୍㒊࡟ࡣ⎔ቃ┬ࡢ㔠ᒓ㊊⎔ࢆ⿦╔ࡋࡓࠋ ㄪᰝࡣ 2019 ᖺ 9 ᭶ 3 ᪥㸦ᪧᓥ㸧
ࠊ4 ᪥㸦໭すྎᆅࠊすஅ὾㸧ࠊ5 ᪥㸦༡す὾㸧࡟⾜࡞ࡗࡓࠋኪ㛫㘓㡢ࡣ 9 ᭶ 3 ᪥᪥ἐࠥ4 ᪥᪥ࡢฟࡲ࡛ࠊኪ㛫ㄪᰝࡣ 9 ᭶ 4 ᪥ 18:30ࠥ20:30 ࡟ᐇ᪋ࡋࡓࠋࡲࡓ 9 ᭶ 9 ᪥࡟ࡣㄪᰝ⯪࡛ᓥࡢ࿘ᅖࢆ㸯࿘ࡋࠊᓥୖ࡟࠸ࡿᾏ㫽ࡢ✀࡜ಶయᩘࢆグ㘓ࡋࡓࠋ㸰−㸰㸬㝣㫽ศᕸ 㝣㫽ࡢ⏕ᜥ≧ἣࢆ᫂ࡽ࠿࡟ࡍࡿࡓࡵࠊ⮬ື᧜ᙳ⿦⨨࡟ࡼࡿ᧜ᙳ࠾ࡼࡧ┤᥋ほᐹࢆ⾜ࡗࡓࠋ㝣㫽ࡢ㣗≀࡜࡞ࡿ⠇㊊ື≀ࡸ✀Ꮚࡣᪧᓥ࡟㞟୰ࡋ࡚࠸ࡿࡓࡵࠊᪧᓥୖࡢ㸯࢝ᡤ࡟Ỉ┙ࢆ⨨ࡁࠊ㣕᮶ࡍࡿ㫽㢮ࢆ⮬ື᧜ᙳ⿦⨨㸦Acorn6210㸧࡛グ㘓ࡋࡓࠋㄪᰝࡣ
9 ᭶ 3 ᪥ 12:30ࠥ9 ᭶ 4 ᪥ 15:30 ࡟ᐇ᪋ࡋࡓࠋᪧᓥࠊ໭すྎᆅࠊすஅ὾ࠊ༡す὾࡛ࡣࠊ㋃ᰝ୰࡟㝣㫽ࢆほᐹࡋࡓሙྜ࡟✀࡜ಶయᩘࢆグ㘓ࡋࡓࠋ㸰−3㸬ᩢṚయ᥇㞟 ᪧᓥࠊ໭すྎᆅࠊすஅ὾ࠊ༡す὾࡛ࡣࠊ㋃ᰝ୰࡟㫽㢮ࡢᩢṚయࢆⓎぢࡋࡓሙྜࡣ
㐺ᐅ᥇㞟ࡋࠊ✀ࢆグ㘓ࡋࡓࠋᪧᓥࠊ໭すྎᆅࠊᪧᓥୗࡢὝ✰࡛ࡣከᩘࡢ㫽㢮㦵ࡀⓎぢࡉࢀࡓࡓࡵࠊྍ⬟࡞㝈ࡾࡇࢀࡽࢆ᥇㞟ࡋࡓࠋࡇࢀࡽࡢ㫽㢮㦵ࡣ㒊఩ࡈ࡜࡟✀ࢆྠᐃࡋࠊ✀ࡈ࡜ࡢ᭱ᑠಶయᩘࢆ⟬ฟࡋࡓࠋࡓࡔࡋࠊ࢝ࢶ࢜ࢻࣜࡢ㦵ࡣ㠀ᖖ࡟ከࡃⓎぢࡉࢀࡓࡓࡵศᯒ࠿ࡽ㝖እࡋࡓࠋ㸰−㸲㸬ᕢᮦศᯒ すஅᓥ࡟࠾ࡅࡿᾏ㫽࡟ࡼࡿᕢᮦ฼⏝ࢆ᫂ࡽ࠿࡟ࡍࡿࡓࡵࠊᪧᓥࠊ໭すྎᆅࠊすஅ
὾ࠊ༡す὾࡛࢝ࢶ࢜ࢻࣜࡢᕢࢆ᧜ᙳࡋࠊGPS ࡛఩⨨ࢆグ㘓ࡍࡿ࡜࡜ࡶ࡟ࠊ෗┿࠿ࡽᕢᮦࢆศᯒࡋࡓࠋᕢᮦࡣேᕤ≀ࠊⲡᮏࠊ㫽㸦㦵࠾ࡼࡧ⩚ẟ㸧ࠊὶᮌࠊ㨶ࠊᾏ⸴࡟ศࡅࠊ
5㸣ࢆ᭱ᑠ༢఩࡜ࡋ࡚ᕢ࡟༨ࡵࡿ๭ྜࢆᴫᩘ࡛グ㘓ࡋࡓࠋᪧᓥ࡛ࡣ࢝ࢶ࢜ࢻࣜ࠾ࡼ
ࡧ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜࡢᕢࢆྛ 10 ಶ᥇㞟ࡋࡓࠋ− 82 −

㸰−㸳㸬࣮ࣟ࢞ࡢᅇ཰࡜タ⨨ ୖ㝣ㄪᰝ௨๓ࡢᾏ㫽ࡢ⏕ᜥ≧ἣࢆ᫂ࡽ࠿࡟ࡍࡿࡓࡵࠊ2016 ᖺ 10 ᭶࡟ᪧᓥୖ࡟タ⨨ࡋࡓ⮬ື㘓㡢⿦⨨ 1 ྎ㸦Wildlife acoustics SongMeter4㸧ࢆᅇ཰ࡋࠊゎᯒࡋࡓࠋ࣑ࢬࢼࢠࢻࣜ⛉࠾ࡼࡧ࣑࢘ࢶࣂ࣓⛉ࡢ㫽ࡣኪ㛫࡟✀≉␗ⓗ࡞㬆ࡁኌ࡛㬆ࡃࡓࡵࠊ㘓㡢ෆᐜ࠿ࡽ㣕᮶≧ἣࢆ᫂ࡽ࠿࡟࡛ࡁࡿࠋ㘓㡢⿦⨨࡟ࡣࠊ2016 ᖺ 11 ᭶ 1 ᪥࠿ࡽࣂࢵࢸࣜ
࣮ࡢษࢀࡓ 2018 ᖺ 7 ᭶ 8 ᪥ࡲ࡛ࡢ㡢ኌࡀグ㘓ࡉࢀ࡚࠸ࡓࠋ㘓㡢ࡣẖ᪥᪥ࡢฟࡢ 2᫬㛫๓࠿ࡽ 1 ᫬㛫༙ࡢ㛫࡟ࠊ1 ศ㛫ࡢ㘓㡢࡜ 14 ศ㛫ࡢ࢖ࣥࢱ࣮ࣂࣝࢆ 6 ᅇ⧞ࡾ㏉ࡋࡓࠋࡇࡢ㘓㡢グ㘓࠿ࡽ㡢ኌศᯒ⏝ࡢࢯࣇࢺ࢙࢘࢔ Kaleidoscope ver 5.1.9 (WildlifeAcoustics)࡛㬆ࡁኌࢆ⮬ືᢳฟࡋࠊྛ 1 ศ㛫ࡢ㘓㡢࡟࠾ࡅࡿᑐ㇟✀ࡢ㬆ࡁኌࡢ᭷↓ࢆグ㘓ࡋࡓࠋᢳฟࡉࢀࡓ㬆ࡁኌࡣࢫ࣌ࢡࢺࣟࢢ࣒ࣛࡢ┠ど☜ㄆ࡜㡢ኌࡢ⫈ྲྀ࡟ࡼࡾ✀ࢆྠᐃࡋࡓࠋ⮬ືᢳฟࡢ࿘Ἴᩘᖏࡣ 0-4000Hzࠊ᳨ฟࡍࡿ㡢ኌࡢ㛗ࡉࡣ 0.1-1 ⛊ࠊࢩࣛࣈࣝ㛫ࡢࢠࣕࢵࣉࡣ 1 ⛊࡜ࡋࡓࠋྛ᪥ࡢ 6 ᅇࡢ㘓㡢࡟ᑐࡍࡿ㬆ࡁኌࢆྵࡴ㘓㡢ࡢ๭ྜࢆࠊྛᾏ㫽ࡢ㘓㡢㢖ᗘ࡜ࡋࡓࠋศᯒࡣẖ᭶ 1 ᪥ࠊ11 ᪥ࠊ21 ᪥ࢆᑐ㇟࡜ࡋࠊኚື
ࢆᖹ⁥໬ࡍࡿࡓࡵ୕㡯ࡢ⛣ືᖹᆒࢆồࡵࡓࠋ ෤Ꮨࡢ㫽㢮ࡢ㣕᮶≧ἣࡢࣔࢽࢱࣜࣥࢢࡢࡓࡵࠊᪧᓥࠊ໭すྎᆅࠊ༡す὾࡟࠾࠸࡚⮬ື㘓㡢⿦⨨㸦Wildlife Acoustics SongMeter2㸧࠾ࡼࡧ⮬ື᧜ᙳ⿦⨨㸦LTL Acorn 6210㸧ࢆタ⨨ࡋࡓࠋ⮬ື㘓㡢⿦⨨ࡣࠊẖ᪥ 6:00ࠥ7:01 ࠾ࡼࡧ 19:00ࠥ21:01 ࡢ㛫ࠊ1 ศ㛫ࡢ㘓㡢࡜ 14 ศ㛫ࡢ࢖ࣥࢱ࣮ࣂࣝࢆ⧞ࡾ㏉ࡍタᐃ࡜ࡋࡓࠋ⮬ື᧜ᙳ⿦⨨ࡣࠊẖ᪥ 9:00ࠊ
12:00ࠊ15:00 ࡟᧜ᙳࡍࡿタᐃ࡜ࡋࡓࠋ
㸰−㸴㸬Ᏻᐃྠ఩యẚศᯒ⏝ࢧࣥࣉࣝ ᾏ㫽࡟ࡼࡿᾏᇦ࠿ࡽ㝣ᇦ࡬ࡢᰤ㣴ሷ౪⤥ࡀᓥࡢ≀㉁ᚠ⎔࡟୚࠼ࡿᙳ㡪ࢆ᫂ࡽ࠿࡟ࡍࡿࡓࡵࠊᪧᓥ࡛᳜≀ࠊ⠇㊊ື≀ࠊᅵࡢ᥇㞟ࢆ⾜ࡗࡓࠋࡲࡓࠊすᾏᓊࠊ໭すྎᆅࠊ
༡すᾏᓊ࡛ᅵࡢ᥇㞟ࢆ⾜ࡗࡓࠋ᳜≀ࡣྛ✀ྛ 10 ಶయࡢⴥࡲࡓࡣⱼࡢ୍㒊ࢆ᥇㞟ࡋࢩࣜ࢝ࢤ࡛ࣝ஝⇱ࡉࡏ࡚ಖᏑࡋࡓࠋ⠇㊊ື≀ࡣྛ✀ྛ 10 ಶయࢆ᥇㞟ࡋ 99%࢚ࢱࣀ
࣮࡛ࣝಖᏑࡋࡓࠋᅵࡣ㫽㢮ࡢ᤼ἥ≀ࡀ࡞࠸ሙᡤࢆ㑅ࡧᆅ⾲㠃ࢆྲྀࡾ㝖࠸ࡓୖ࡛ࢥ࢔ࢧࣥࣉ࣮࡛ࣛ᥇㞟ࡋࡓࠋᅵࡣ 1 ㄪᰝᆅ࡟ࡘࡁ 5 ࣨᡤ࡛᥇㞟ࡋࡓࠋ㸱㸬⤖ᯝ㸱−㸯㸬ᾏ㫽ࡢศᕸ ᾏ㫽ࡢ⦾Ṫドᣐࢆ᥈⣴ࡋࡓ⤖ᯝࠊ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜࠊ࢝ࢶ࢜ࢻࣜࠊ࢔࢜ࢶࣛ࢝ࢶ࢜ࢻࣜࠊࢡࣟ࢔ࢪࢧࢩࠊ࢜࢜࢔ࢪࢧࢩࡢᕢࡸ༸ࠊ㞮ࡀ☜ㄆࡉࢀࡓࠋ ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜࡢᕢ✰ࡣᪧᓥୖ࡟ 296 ࣨᡤࡀグ㘓ࡉࢀࡓ㸦ᅗ 2a㸧ࠋࡲࡓࠊᪧ
ᓥ┤ୗࡢὝ✰ෆࡢ 1 ࣨᡤ࡛ᮏ✀ࡢࡶࡢ࡜⪃࠼ࡽࢀࡿ༸ࡀグ㘓ࡉࢀࡓࠋࡑࢀ௨እࡢሙ
ᡤ࡛ࡣᮏ✀ࡢᕢࡣぢࡘ࠿ࡽ࡞࠿ࡗࡓࠋᪧᓥୖࡢᕢ✰ෆࢆㄪᰝࡋࡓ⤖ᯝࠊ6±5.5%㸦n=5,− 83 −

PHDQ6'㸧࡛⏕ࡁࡓ㞮ࡀࠊ࡛Ṛࢇࡔ㞮ࡀࠊ࡛༸ࡀࠊ࡛ᡂ㫽࣌࢔ࡢࡳࡀࠊࡑࢀࡒࢀࡳࡘ࠿ࡗࡓࡀࠊ㸣ࡢᕢࡣ⦾Ṫ࡟౑⏝ࡉࢀ࡚࠸࡞࠿ࡗࡓࠋኪ㛫ㄪᰝ࡛ࡣ  ಶయࡢ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜࡢ㣕᮶ࢆ☜ㄆࡋࡓࠋࡑࡢ࠺ࡕ  ಶయ࡟ࡣ㔠ᒓ㊊⎔ࢆ⿦╔ࡋᨺ㫽ࡋࡓࠋᪧᓥ࡛ࡣከᩘࡢಶయࡀኪ㛫࡟㬆࠸࡚࠸ࡓࡀࠊ௚ࡢሙᡤ࡛ࡣᮏ✀ࡢኌࡣ⪺࠿ࢀ࡞࠿ࡗࡓࠋࡲࡓࠊ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜ௨እࡢ࣑ࢬࢼࢠࢻࣜ⛉࠾ࡼࡧ࣑࢘ࢶࣂ࣓⛉ࡢ㫽㢮ࡢ㬆ࡁኌࡶグ㘓ࡉࢀ࡞࠿ࡗࡓࠋ ࢝ࢶ࢜ࢻࣜࡣᪧᓥୖ࡛  ಶయࡢ㞮ࡀࠊすஅ὾࡛  ಶయࡢ㞮࡜ᢪ༸୰ࡢ  ᕢࡀࠊ໭すྎᆅ࡛  ಶయࡢ㞮ࡀࠊ༡す὾࡛  ಶయࡢ㞮ࡀぢࡘ࠿ࡗࡓ㸦ᅗ E㸧ࠋࡲࡓࠊ8$9࡟ࡼࡿ⏬ീ࠿ࡽࡣ໭அ὾࠾ࡼࡧ༡὾࡛ᑡ࡞ࡃ࡜ࡶྛ  ᕢࡢぶ㫽ࡀ࠸ࡿᕢࡀ☜ㄆࡉࢀࡓࠋ㞮ࡣぶࡀᢪ㞮ࡋ࡚࠸ࡿᏤ໬┤ᚋࡢ⏘ẟࡢ࡞࠸ಶయ࠿ࡽࠊ㢼ษ⩚ࡀ⏕࠼ᥞࡗࡓᕢ
❧ࡕ┤๓ࡢಶయࡲ࡛ᵝࠎ࡞ẁ㝵ࡢࡶࡢࡀぢࡽࢀࡓࠋࡇࡢ௚࡟࢔ࣉ࣮ࣟࢳࡢ㞴ࡋ࠸⁐ᒾୖ࡟  ಶయ௨ୖࡢ㞮ࡀほᐹࡉࢀࡓࠋ8$9 ࡟ࡼࡿ᧜ᙳ࡛ࡣࠊᾏᓊ࠿ࡽ P ⛬ᗘෆ㝣ࡢ⁐ᒾୖ࡛ࡶ㞮ࡀぢࡽࢀࡓࠋᪧᓥୖࠊすஅ὾ࠊ໭すྎᆅ࡛ࡣከᩘࡢྂᕢࡀࠊ༡す὾࡛ࡣྂᕢ࡜༸Ẇࡀྛ㸯ࣨᡤ࡛ぢࡘ࠿ࡗࡓࠋࡇࡢ௚࡟௒ᖺᕢ❧ࡗࡓ࡜⪃࠼ࡽࢀࡿⱝ㫽ࡀᪧᓥࠊすஅ὾ࠊ໭すྎᆅ࿘㎶࡛  ಶయ௨ୖほᐹࡉࢀࡓࠋ࢝ࢶ࢜ࢻࣜࡢ⦾Ṫᆅ࡟ࡣࢺࣅ࢘࢜࡞࡝ࡢྤࡁᡠࡋࡀከᩘⴠࡕ࡚࠸ࡓࠋࡲࡓࠊᡂ㫽ࡀㄪᰝ⪅࡟㦫࠸࡚ྤࡁᡠࡋࢆࡍࡿࡇ࡜ࡶ࠶ࡗࡓࠋ ࢔࢜ࢶࣛ࢝ࢶ࢜ࢻࣜࡣᪧᓥୖ࡛  ಶయࡢᕢ❧ࡕ๓ࡢ㞮࡜ᢪ༸୰ࡢ  ᕢࡀࠊすஅ὾࡛ᢪ༸୰ࡢ  ᕢࡀほᐹࡉࢀࡓ㸦ᅗ F㸧ࠋ඲࡚ࡢᕢࡣᖹࡽ࡞◁ᆅ࡟࠶ࡾࠊᕢᮦࡣ౑⏝ࡉࢀ࡚࠸࡞࠿ࡗࡓࠋࡲࡓࠊ ᭶  ᪥  ᫬ࡈࢁ࡟すஅ὾ࡢ୰ኸ㒊࡟ᑡ࡞ࡃ࡜ࡶ  ಶయࡢᡂ㫽࡜  ಶయࡢⱝ㫽ࡀ㞟ࡲࡗ࡚࠸ࡿࡢࡀほᐹࡉࢀࡓࠋ ࢡࣟ࢔ࢪࢧࢩࡣࠊ༡す὾ࡢዟࡢ㸯ࣨᡤ࡛༸ࡢẆࡀぢࡘ࠿ࡗࡓࠋ௵ពࡢほᐹ࡛ࡣࠊᅗ  ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜࡢᕢ✰ࠊ࢝ࢶ࢜ࢻࣜࡢ㞮ࠊ࢔࢜ࢶࣛ࢝ࢶ࢜ࢻࣜࡢᕢ࡜㞮ࡢ఩⨨)LJ  /RFDWLRQV RI EXUURZV RI :HGJHWDLOHG 6KHDUZDWHUV FKLFNV RI %URZQ %RRELHV QHVW DQGFKLFNVRI0DVNHG%RRELHV− 84 −ㄪᰝᆅࡢ඲ᇦ࡛ಶయࡀほᐹࡉࢀࡓࡀࠊ≉࡟すஅ὾ࡢ༡㒊࡛⣙  ಶయࠊ໭㒊࡛⣙ ಶయࡢ㞟ᅋࡀぢࡽࢀࡓࠋࡲࡓࠊすஅ὾ࡢ୰ኸ㒊࡛ࡣ  ᭶  ᪥  ᫬ࡈࢁ࡟  ಶయࡀᐦ㞟ࡋ࡚ᆅୖ࡟㝆ࡾ࡚࠸ࡿጼࡀぢࡽࢀࡓࠋ ࢜࢜࢔ࢪࢧࢩࡣすஅ὾໭㒊࡛ᕢ❧ࡕ๓ࡢ㞮ࡀ  ಶయほᐹࡉࢀࡓࠋすஅ὾ࡢ࿘㎶࡛ࡣᑡᩘࡢ࢜࢜࢔ࢪࢧࢩࡀ㣕⩧ࡋ࡚࠸ࡓࡀࠊ኱ࡁ࡞㞟ᅋࡣぢࡽࢀ࡞࠿ࡗࡓࠋ
 ,& ࣞࢥ࣮ࢲ࣮࡟ࡼࡿኪ㛫㘓㡢࡛ࡣࠊ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜ࡜࢝ࢶ࢜ࢻࣜ௨እࡢ㬆ࡁኌࡣ᳨ฟࡉࢀ࡞࠿ࡗࡓࠋ ᾏୖ࠿ࡽࡢほᐹ࡛ࡣࠊᾏᓊ㒊୍࿘ࡢྜィ࡛࢝ࢶ࢜ࢻࣜ  ಶయࠊࢡࣟ࢔ࢪࢧࢩ⣙ ಶయࠊ࢜࢜࢔ࢪࢧࢩ  ಶయࠊࢭࢢࣟ࢔ࢪࢧࢩ  ಶయࡀほᐹࡉࢀࡓࠋࡲࡓ⯪ୖ࡛ࡣ࢔࢝࢔ࢩ࢝ࢶ࢜ࢻࣜ 6XODVXOD ಶయ㸦〓Ⰽᆺ  ⱝ㫽 㸧ࡀほᐹࡉࢀࡓࠋ㸱í㸰㸬㝣㫽ศᕸ ᪧᓥࡢ⮬ື᧜ᙳ⿦⨨࡛ࡣ㝣㫽ࡣ☜ㄆࡉࢀ࡞࠿ࡗࡓࠋࡲࡓࠊ௵ពࡢほᐹ࡛ࡶ㝣㫽ࡣグ㘓ࡉࢀ࡞࠿ࡗࡓࠋࡓࡔࡋࠊ ᭶  ᪥࡟ࡣすஅᓥࡢ༡すἈ⣙ P ࡟೵Ἡࡋࡓㄪᰝ⯪ୖ࡛࢖ࢯࣄࣚࢻࣜ 0RQWLFRODVROLWDULXV ࡢⱝ㫽  ಶయࡀほᐹࡉࢀࡓࠋ㸱í㸱㸬ᩢṚయ᥇㞟 ᪧᓥ࡛ࡣ  ಶయࠊ໭すྎᆅ࡛ࡣ  ಶయࠊすஅ὾࡛ࡣ  ಶయ௨ୖࠊ༡す὾࡛ࡣ  ಶయࡢ࢝ࢶ࢜ࢻࣜࡢ㞮ࡢṚయࡀぢࡘ࠿ࡗࡓࠋすஅ὾໭㒊࡛ࡣ  ಶయࠊ༡す὾࡛ࡣ  ಶయࡢࢡࣟ࢔ࢪࢧࢩᡂ㫽ࡢṚయࡀぢࡘ࠿ࡗࡓࠋすஅ὾໭㒊࡛ぢࡘ࠿ࡗࡓࢡࣟ࢔ࢪࢧࢩࡢṚయࡣⓑ㦵໬ࡋ࡚࠸ࡓࡀࠊୖ⭎㦵ࠊᑻ㦵ࠊᶨ㦵࡞࡝ୖ⫥ᖏࡢ⟶㦵ࡀ࡞ࡃ࡞ࡗ࡚࠸ࡿࡶࡢࡀከ࠿ࡗࡓࠋ࢝ࢶ࢜ࢻࣜࡢṚయᅗ  すஅᓥ࡛ぢࡘ࠿ࡗࡓࢡࣟ࢔ࢪࢧࢩࡢྛ㒊఩ࡢ㦵ࡢᩘ࡟ࡣࠊከࡃࡢ࢝ࢶ࢜ࣈࢩ)LJ  1XPEHU RI ERQHV RI %URZQ 1RGGLHV GHWHFWHG RQ

࣒ࢩ࠾ࡼࡧࣁࢧ࣑࣒ࢩࡀ

1LVKLQRVKLPD௜╔ࡋ࡚࠸ࡓࠋ

− 85 − ᪧᓥࠊ໭すྎᆅࠊᪧᓥୗࡢὝ✰࡛᥇㞟ࡋࡓ㦵࠿ࡽࡣࠊ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜࠊ࣮࢜
ࢫࢺ࣑ࣥ࢘ࢶࣂ࣓ࠊࢡࣟ࢔ࢪࢧࢩࠊࢡࣟࣁࣛ࢔ࢪࢧࢩ &KOLGRQLDVK\EULGXVࠊࣄࢱ࢟⛉ࡢ  ✀ࠊࢩࣟࣁࣛ 7XUGXVSDOOLGXVࠊࢶࣂ࣓ +LUXQGRUXVWLFD ࡢ㦵ࡀぢࡘ࠿ࡗࡓ㸦⾲ 㸧ࠋࣄࢱ࢟⛉ࡢ  ✀ࡣ㊊᰿୰㊊㦵ࡀ  ᮏࡀぢࡘ࠿ࡾࠊࢶࢢ࣑ᒓ 7XUGXV ࡢྍ⬟ᛶࡀ㧗࠿ࡗࡓࠋ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜ࡜ࢡࣟ࢔ࢪࢧࢩ࡛ࡣᗂ㫽ࡢ㦵ࡀྵࡲࢀ࡚࠸ࡓࡀࠊ௚✀ࡣᡂ㫽ࡢ㦵ࡢࡳࡀぢࡘ࠿ࡗࡓࠋࢡࣟ࢔ࢪࢧࢩࠊ࣮࢜ࢫࢺ࣑ࣥ࢘ࢶࣂ࣓ࡣࡑࢀࡒࢀ  ಶయࠊ ಶయࡔࡗࡓࡀࠊ௚✀ࡣ  ಶయ௨ୗࡔࡗࡓࠋࢶࣂ࣓ࡣ࡯ࡰ඲㌟ࡢ㦵ࡀṧࡗ࡚࠸ࡓࡀࠊ௚ࡣ୺࡟༢⊂ࡢ㦵ࡔࡗࡓࠋࡓࡔࡋࠊⅲཱྀ㦵࡜⫪⏥㦵ࡣࡋࡤࡋࡤୖ⭎㦵࡟㛵⠇ࡋ࡚࠸ࡓࠋⓎぢᩘࡢከ࠿ࡗࡓࢡࣟ࢔ࢪࢧࢩࡢ㦵࡛ࡣࠊୖ⭎㦵ࠊᑻ㦵ࠊᶨ㦵ࠊᡭ᰿୰ᡭ㦵ࡀ඲యࡢ⣙ ࢆ༨ࡵ࡚࠸ࡓ㸦ᅗ 㸧ࠋୖ⭎㦵࠿ࡽ㐃࡞ࡿⅲཱྀ㦵࡜⫪⏥㦵ࢆྵࡵࡿ࡜⣙ ࡜࡞ࡗࡓࠋ⾲  すஅᓥ࡛ぢࡘ࠿ࡗࡓ㫽㦵࡟ྵࡲࢀࡿྛ✀㫽㢮ࡢ᭱ᑠಶయᩘ
7DE0LQLPDOQXPEHURILQGLYLGXDOVLQFOXGHGLQDYLDQERQHVFROOHFWHGRQ1LVKLQRVKLPD㸱í㸲㸬ᕢᮦศᯒ ᕢᮦศᯒࡢ⤖ᯝࠊ࢝ࢶ࢜ࢻࣜࡢᕢ࡟ࡣᪧᓥ࡟⏕⫱ࡍࡿⲡᮏࠊࣉࣛࢫࢳࢵࢡ∦ࡸ࣮ࣟࣉ࡞࡝ࡢேᕤ≀ࠊ㫽ࡢ㦵࡜⩚ẟࠊ㨶ࡢ㦵ࡸࣄࣞࠊὶᮌࠊᾏ⸴➼ࡀ౑⏝ࡉࢀ࡚࠸ࡓࠋ᭱ࡶ㧗㢖ᗘ࡛ฟ⌧ࡋࡓᕢᮦࡣேᕤ≀࡛ࠊ ᕢ୰  ᕢ࡛౑⏝ࡉࢀ࡚࠾ࡾࠊྛᕢࡢᕢᮦ㔞ࡢᖹᆒ ࢆ༨ࡵ࡚࠸ࡓࠋⲡᮏ᳜≀ࡣ ᕢ࠿ࡽ㸦ᕢᮦ㔞ࡢᖹᆒ 㸧ࠊᅗ ࢝ࢶ࢜ࢻࣜࡢᕢᮦෆࡢ᳜≀࡜ேᕤ≀ࡢฟ⌧㢖ᗘ㫽 ⏤ ᮶ ࡢ ⤌ ⧊ ࡣ  ᕢ ࠿ ࡽ)LJ)UHTXHQF\RISODQWDQGDUWLILFLDOPDWHULDOVLQQHVWV㸦㸧ࠊ㨶⏤᮶⤌⧊ࡣ  ᕢ࠿ࡽ

RI%URZQ%RRELHV− 86 −㸦㸧ࠊὶᮌࡣ  ᕢ࠿ࡽ㸦㸧ࠊᾏ⸴ࡣ  ᕢ࠿ࡽ㸦㸧ࠊࡑࢀࡒࢀぢࡘ࠿ࡗࡓࠋࡲࡓࠊ▼ࡢࡳ࡛సࡽࢀࡓᕢࡶほᐹࡉࢀࡓࠋᪧᓥ࡛ࡣᕢᮦ࡜ࡋ࡚࢜ࣄࢩࣂࡀඃ༨ࡍࡿᕢࡀከᩘぢࡽࢀࡓࡀࠊᪧᓥእ࡛ࡣᪧᓥ࠿ࡽ㐲ࡃ࡞ࡿ࡟ࡘࢀⲡᮏࡢ฼⏝㢖ᗘࡀపୗࡋࡓ㸦ᅗ 㸧ࠋேᕤ≀ࡢ౑⏝ࡣᪧᓥ࠿ࡽࡢ㊥㞳࡜ࡢ㛵ಀࡣᙅࡃࠊ࡝ࡢሙᡤ࡛ࡶ㧗㢖ᗘ࡛౑⏝ࡉࢀ࡚࠸ࡓࠋ㸱í㸳㸬࣮ࣟ࢞ࡢᅇ཰࡜タ⨨  ᖺ࠿ࡽ  ᖺࡲ࡛ࡢ㡢ኌศᯒࡢ⤖ᯝࠊ࣑ࢬࢼࢠࢻࣜ⛉࠾ࡼࡧ࣑࢘ࢶࣂ࣓⛉ࡢ㫽㢮࡜ࡋ࡚࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜ࡜࣮࢜ࢫࢺ࣑ࣥ࢘ࢶࣂ࣓ࡀ᳨ฟࡉࢀࡓࠋ๓⪅ࡢ㬆ࡁኌࡣ  ᭶࠿ࡽ  ᭶ࡢ㛫࡟㘓㡢ࡉࢀ࡚࠾ࡾࠊቑῶࡣ࠶ࡿࡶࡢࡢ ࠥࡢ㧗࠸㢖ᗘ࡛グ㘓ࡉࢀ࡚࠸ࡓ㸦ᅗ 㸧ࠋᚋ⪅ࡣ  ᭶࠿ࡽ  ᭶ࡢ㛫࡟㘓㡢ࡉࢀ࡚࠸ࡓࡀࠊࡑࡢ㢖ᗘࡣ㧗ࡃ࡜ࡶ 㸣⛬ᗘࡔࡗࡓࠋྠ᫬࡟㬆࠸࡚࠸ࡿಶయᩘࡣ୙᫂ࡔࡀࠊ୧✀ඹ࡟ከᩘಶయࡀྠ᫬࡟㬆ࡃࡇ࡜ࡶከ࠿ࡗࡓࠋ୍᪉࡛ࠊከᩘࡀ㣕᮶ࡋ࡚࠸ࡿ᫬ᮇ࡛࠶ࡗ࡚ࡶ᪥࡟ࡼࡗ࡚ࡣ୍ษ㘓㡢ࡉࢀ࡚࠸࡞࠸᪥ࡀ࠶ࡗࡓࠋ㘓㡢ࡀ඲ࡃ࡞࠸᪥࡟ࡣ㞵⁲ࡸᙉ㢼ࡢ㡢ࡀ㘓㡢ࡉࢀ࡚࠸ࡿሙྜࡀ࠶ࡗࡓࠋ ⮬ື㘓㡢⿦⨨ࡣᪧᓥࠊ໭すྎᆅࠊ༡す὾ࡢྛ㸯ᆅⅬ࡟タ⨨ࡋࡓ㸦ᅗ㸯ࠊձࠥճ㸧ࠋ⮬ື᧜ᙳ⿦⨨ࡣ⮬ື㘓㡢⿦⨨࡜ྠᆅⅬࡢ௚ࠊ༡す὾ࡢ⁐ᒾୖᅗ  ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜ࡜࣮࢜ࢫࢺ࣑ࣥ࢘ࢶࣂ࣓ࡢ㬆ࡁኌࡢࡢ㸯ᆅⅬ㸦ᅗ ࠊմ㸧࡟㘓㡢㢖ᗘࡢᏘ⠇ኚ໬タ⨨ࡋࡓࠋࡇࢀࡽࡣ )LJ6HDVRQDOFKDQJHRIIUHTXHQF\RIUHFRUGHGYRLFHVRI:HGJHᖺᗘ௨㝆࡟ᅇ཰ࡍࡿணWDLOHG6KHDUZDWHUDQG7ULVWUDP¶V6WRUP3HWUHOᐃ࡛࠶ࡿࠋ㸱í㸴㸬Ᏻᐃྠ఩యẚศᯒ⏝ࢧࣥࣉࣝ ᪧᓥ࡛ࡣࠊ࢜ࣄࢩࣂ  ಶయࠊࢫ࣋ࣜࣄࣘࡢྛ  ಶయࠊ࢖ࢾࣅ࢚  ಶయࠊ⠇㊊ື≀࡜ࡋ࡚ࢺࣅ࢝ࢶ࢜ࣈࢩ࣒ࢩ 'HUPHVWHV DWHUࠊࣁࢲ࢝࢔ࣜ &DUGLRFRQG\OD NDJXWVXFKLࠊࢥࣔࣜࢢࣔ㢮ࠊ࢜࢞ࢧ࣡ࣛࣄ࣓ࢼ࣓࣒࢞࢝ࢩ 1\VLXV FDOHGRQLDHࠊࢥࣄࢤࢪࣟࣁࢧ࣑
࣒ࢩ (XERUHOOLD DQQXOLSHV ࢆྛ  ಶయࠊࣖࢽ࢖ࣟࣁࢧ࣑࣒ࢩ $QLVRODELV SLFHD ࢆ  ಶయ᥇㞟ࡋࡓࠋᅵࡣᪧᓥୖࠊ໭すྎᆅࠊすஅ὾༡㒊ࠊ༡す὾࡛᥇㞟ࡋࡓࠋࢧࣥࣉࣝࡣ

− 87 −௒ᚋศᯒࢆ⾜࠺ணᐃ࡛࠶ࡿࠋ㸲㸬⪃ᐹ
 2013 ᖺᄇⅆ௨๓࡟☜ㄆࡉࢀ࡚࠸ࡓᾏ㫽ࡢ࠺ࡕࠊ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜࠊ࢝ࢶ࢜ࢻࣜࠊ
࢔࢜ࢶࣛ࢝ࢶ࢜ࢻࣜࠊࢡࣟ࢔ࢪࢧࢩࠊ࢜࢜࢔ࢪࢧࢩࡢ 5 ✀ࡢ⦾Ṫࡀ☜ㄆࡉࢀࡓࠋᪧᓥ࡛ࡣከᩘࡢ࢝ࢶ࢜ࢻࣜ࡜ᑡᩘࡢ࢔࢜ࢶࣛ࢝ࢶ࢜ࢻࣜ࡜࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜࡢ⦾Ṫࡀ☜ㄆࡉࢀࡓࠋࡲࡓከᩘࡢ㘓㡢グ㘓࠿ࡽࡣ࣮࢜ࢫࢺ࣑ࣥ࢘ࢶࣂ࣓ࡀ⦾Ṫᮇ࡟㣕᮶ࡋ࡚࠸ࡿࡇ࡜ࡀ᫂ࡽ࠿࡟࡞ࡗࡓࠋすஅ὾࡛ࡣከᩘࡢ࢝ࢶ࢜ࢻࣜ࠾ࡼࡧᑡᩘࡢ࢔࢜ࢶࣛ࢝ࢶ࢜ࢻࣜࡢ⦾Ṫࡀ☜ㄆࡉࢀࡿ࡜ඹ࡟ࠊ1 ಶయࡢ࢜࢜࢔ࢪࢧࢩࡢ㞮ࡀぢࡘ࠿ࡗࡓࠋ໭すྎᆅ࡛ࡣከᩘࡢ࢝ࢶ࢜ࢻࣜࡢ⦾Ṫࡀ☜ㄆࡉࢀࡓࠋ༡す὾࡛ࡣ 1 ಶయࡢ࢝ࢶ࢜ࢻࣜࡢ㞮࠾ࡼࡧࢡࣟ࢔ࢪࢧࢩࡢ༸Ẇࡀぢࡘ࠿ࡗࡓࠋ
࣭࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜ ᪧᓥୖ࡛ࡣ 296 ࣨᡤࡢᕢ✰ࡀぢࡘ࠿ࡗࡓࡀࠊ⦾Ṫࡢࡓࡵ࡟฼⏝ࡉࢀ࡚࠸ࡿᕢ✰ࡣ⣙ 10%ࡔࡗࡓࠋࡇࡢࡇ࡜࠿ࡽࠊᐇ㝿࡟⦾Ṫࡋ࡚࠸ࡿࡢࡣ 30 ࣌࢔⛬ᗘ࡜᥎ᐃࡉࢀࡿࠋࡲࡓࠊᪧᓥୖ࡜┤ୗࡢὝ✰࡛ࡋ࠿ᮏ✀ࡢႠᕢࡣぢࡘ࠿ࡽࡎࠊ᪂ࡓ࡞㝣ᆅࡣᮏ✀ࡢ⦾Ṫ࡟ࡣ฼⏝ࡉࢀ࡚࠸࡞࠸ࡶࡢ࡜⪃࠼ࡽࢀࡿࠋ ኪ㛫࡟ࡣ 465 ಶయࡢ㣕᮶ࡀ☜ㄆࡉࢀࡓࡀࠊࡑࡢ࡯࡜ࢇ࡝ࡣ㠀⦾Ṫಶయ࡜⪃࠼ࡽࢀࡿࠋࡲࡓࠊ⮬ື㘓㡢⿦⨨ࡢグ㘓࠿ࡽࠊᮏ✀ࡣ 2 ᭶㡭࡟㣕᮶ࡋ࡚Ⴀᕢ࡟ධࡾࠊ11 ᭶㡭࡟ᕢ❧ࡘ࡜⪃࠼ࡽࢀࡿࠋᑠ➟ཎㅖᓥ࡛ࡣ 3 ᭶㡭࠿ࡽ㣕᮶ࡋ 10 ᭶ࠥ11 ᭶࡟ᕢ❧ࡘ࡜ࡉࢀ࡚࠾ࡾ㸦⢄ᒣࠊ1930㸧ࠊすஅᓥࡶࡇࢀ࡟୍⮴ࡋ࡚࠸ࡿࠋ௒ᚋࡣ⦾Ṫಶయࡀቑຍࡋࠊ
⦾Ṫ㞟ᅋࡢࢧ࢖ࢬࡀ኱ࡁࡃ࡞ࡿࡇ࡜ࡀᮇᚅࡉࢀࡿࠋ ᑠ➟ཎㅖᓥ࡛ࡣᮏ✀ࡣᆅ୰ࡢ✰ࡔࡅ࡛࡞ࡃࠊᒾࡢ㝽㛫࡞࡝࡟ࡶႠᕢࡍࡿࠋ⌧ᅾࡢ࡜ࡇࢁ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜࡀᕢ✰ࢆ᥀ࢀࡿሙᡤࡣᅵተࡀሁ✚ࡋ࡚࠸ࡿᪧᓥୖ࡟㝈ࡽࢀࡿࡀࠊࡃࡔࡅࡓ⁐ᒾࡀሁ✚ࡋ࡚࠸ࡿሙᡤࡣᓥ࡟ᗈࡃศᕸࡋ࡚࠸ࡿࡢ࡛ࠊ⦾Ṫಶయᩘࡀቑຍࡍࢀࡤ⦾Ṫᆅࢆ᪂ࡓ࡞㝣ᆅ࡟ᣑ኱ࡍࡿྍ⬟ᛶࡀ࠶ࡿࠋ࣭࢝ࢶ࢜ࢻࣜ ᪧᓥ࡜すஅ὾࿘㎶ࡔࡅ࡛⣙ 400 ಶయࡢ㞮ࡀ☜ㄆࡉࢀࡓࡇ࡜࠿ࡽࠊᮏ✀ࡣᏳᐃࡋࡓ⦾Ṫ㞟ᅋࢆᙧᡂࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋ᪤࡟ᕢ❧ࡗ࡚࠸ࡿಶయࡶከ࠸࡜⪃࠼ࡽࢀࠊ⦾Ṫᮇ඲య࡛ࡣࡼࡾከࡃࡀ⦾Ṫࡋ࡚࠸ࡿࡣࡎ࡛࠶ࡿࠋ௒ᅇࡣᢪ༸୰ࡢಶయ࠿ࡽᕢ❧ࡕᚋࡢⱝ㫽ࡲ࡛ᵝࠎ࡞ẁ㝵ࡀぢࡽࢀࡓࠋ࢝ࢶ࢜ࢻࣜࡣᏤ໬࠿ࡽᕢ❧ࡕࡲ࡛⣙ 3 ࣨ᭶࠿࠿ࡿࡓࡵ㸦Ospina-Alvarez, 2014㸧ࠊ㐜࠸ಶయࡢᕢ❧ࡕࡣ 12 ᭶௨ᚋ࡜࡞ࡿࠋᮏ✀ࡣ⇕ᖏ࡛ࡣ࿘ᖺ⦾Ṫࡍࡿሙྜࡶ࠶ࡿࡀ㸦Nelson, 2005㸧ࠊᑠ➟ཎ࡛ࡣ⦾Ṫᮇࡢಶయᕪࡣ
ᑡ࡞ࡃࠊ౛ᖺ 5 ᭶ࠥ10 ᭶࡟⦾Ṫࡍࡿ㸦⢄ᒣࠊ1930㸧ࠋすஅᓥࡢ㞟ᅋࡣᑠ➟ཎࡢ௚ᆅᇦ࡟ẚ࡭⦾Ṫᮇࡀ㛗ᮇ໬ࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋ

− 88 − すஅᓥࡣᄇⅆ௨๓࡟ࡣ⣙ 700 ࣌࢔ࡢ࢝ࢶ࢜ࢻࣜࡀ⦾Ṫࡋ࡚࠸ࡓ㸦ᕝୖ࡯࠿ࠊ2005㸧ࠋ⁐ᒾࡢ⿕そ࡟ࡼࡾ⦾Ṫᆅ㠃✚ࡀᑠࡉࡃ࡞ࡾࠊᪧᓥ࿘㎶ࡣ㧗ᐦᗘ໬ࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋ࢝ࢶ࢜ࢻࣜࡣ୍⯡࡟Ⴀᕢᐦᗘࡣࡑࢀ࡯࡝㧗ࡃ࡞ࡽ࡞࠸ࠋ㧗ᐦᗘ໬ࡍࡿ࡜ᡂ㫽ࡸ㞮ࡣ஫࠸࡟ᖸ΅ⓗ࡞⾜ືࢆ⏕ࡌࡿࡇ࡜ࡀ࠶ࡿࡓࡵࠊࡑࡢ⦆࿴ࡢࡓࡵ࡟⦾Ṫᮇࢆࡎࡽࡍಶయࡀ⌧ࢀ࡚࠸ࡿࡢ࠿ࡶࡋࢀ࡞࠸ࠋ ࡲࡓࠊすஅᓥ࡛ࡣ᳜≀ࡀᑡ࡞ࡃᕢᮦࡀ୙㊊ࡋ࡚࠸ࡿࡓࡵࠊᕢᮦࢆᕠࡿ➇த࡛⦾Ṫ㛤ጞ᫬ᮇ࡟ᕪࡀ⏕ࡌ࡚࠸ࡿྍ⬟ᛶࡶ࠶ࡿࠋ⦾Ṫᐦᗘࡀࡲࡔ㧗ࡃ࡞࠿ࡗࡓ࡜⪃࠼ࡽࢀ
ࡿ 2016 ᖺ 10 ᭶ࡢୖ㝣ㄪᰝ࡛ࡣᕢ❧ࡕ๓ࡢ㞮ࡣぢࡘ࠿ࡗ࡚࠾ࡽࡎ㸦ᕝୖࠊᮍⓎ⾲㸧ࠊ㧗ᐦᗘ໬ࡀ⦾Ṫᮇࡢ㛗ᮇ໬࡟ᙳ㡪ࡋ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿࠋ ࢝ࢶ࢜ࢻࣜࡢ⦾Ṫᆅ࡛ࡣከᩘࡢࢡࣟ࢔ࢪࢧࢩࡢ㦵ࡀぢࡘ࠿ࡗࡓࡀࠊࡑࡢ࡯࡜ࢇ࡝ࡀୖ⫥ᖏ⏤᮶ࡢ⟶㦵ࡔࡗࡓࠋ࢝ࢶ࢜ࢻࣜࡢᕢ࡟ࡣ㫽ࡢ⟶㦵ࡀ㢖⦾࡟౑⏝ࡉࢀ࡚࠾ࡾࠊࡇࢀࡽࡢ㦵ࡣᕢᮦ࡜ࡋ࡚ᣢࡕ㎸ࡲࢀࡓࡶࡢ࡜⪃࠼ࡽࢀࡿࠋすஅ὾໭㒊࡛ࡣୖ⫥ᖏࡢ⟶㦵ࢆḞࡃࢡࣟ࢔ࢪࢧࢩࡢⓑ㦵Ṛయࡀ」ᩘぢࡘ࠿ࡗࡓࡇ࡜࠿ࡽࠊ࢝ࢶ࢜ࢻࣜࡀᕢᮦ࡜ࡋ࡚⟶㦵ࢆᣢࡕཤࡗࡓྍ⬟ᛶࡀ㧗࠸ࠋ ࢝ࢶ࢜ࢻࣜࡀ⦾Ṫࡋ࡚࠸ࡓ໭すྎᆅࡣࠊ2016 ᖺ 7 ᭶ 25 ᪥࡟᧜ᙳࡉࢀࡓ⯟✵෗┿࡛ࡣ௚ࡢ⁐ᒾୖ࡜≉࡟ኚࢃࡽ࡞࠸ᆅ⾲㠃ࡀࢦࢶࢦࢶ࡜ࡋࡓᒾሢ࡛そࢃࢀ࡚࠸ࡓࡀࠊྠ ᖺ 12 ᭶ 20 ᪥ ࡢ ෗ ┿ ࡛ ࡣ ᆅ ⾲ 㠃 ࡀ ᖹ ࡽ ࡟ ࡞ ࡗ ࡚ ࠸ ࡓ 㸦 ᅜ ᅵ ᆅ ⌮ 㝔 ᧜ ᙳ
https://www.gsi.go.jp/gyoumu/gyoumu41000.html㸧ࠋࡇࡇࡣᾏ࡟㏆࠸ࡓࡵἼᾉ࡟ࡼࡿᾐ㣗࡛⾲㠃ࡀ๐ࡽࢀࡿ࡜࡜ࡶ࡟ࠊ○ࡅࡓ⁐ᒾࡢ⣽⢏ࡀሁ✚ࡋᖹᆠ໬ࡋࡓྍ⬟ᛶࡀ࠶ࡿࠋࡇࡇ࡛ࡣከᩘࡢ㞮࡜ྂᕢࡀ☜ㄆࡉࢀࠊ᪂ࡓ࡞⁐ᒾୖ࡛ࡶᖹᆠ໬ࡍࢀࡤ࢝ࢶ࢜ࢻࣜࡀ㞟ᅋ⦾Ṫ࡟฼⏝ࡍࡿࡇ࡜ࡀ᫂ࡽ࠿࡟࡞ࡗࡓࠋࡲࡓࠊෆ㝣ࡢ⁐ᒾୖࡢྛᡤ࡛࢝ࢶ࢜ࢻࣜࡢ༢⊂Ⴀᕢࡀ☜ㄆࡉࢀࠊᖹᆠ໬ࡋ࡚࠸࡞࠸⁐ᒾୖ࡛ࡶᕢࢆ⨨ࡅࡿሙᡤࡀᒁᆅⓗ࡟࠶ࢀࡤࠊႠᕢሙᡤ࡜ࡋ࡚฼⏝ྍ⬟࡜࡞ࡿ࡜ゝ࠼ࡿࠋ࢝ࢶ࢜ࢻࣜࡣࡋࡤࡋࡤᓴࡸᒾᲴ
࡞࡝࡛ࡶႠᕢࡍࡿࡇ࡜࠿ࡽ㸦Nelson, 2005㸧ࠊ⁐ᒾୖࡶ₯ᅾⓗ࡞Ⴀᕢ⎔ቃ࡜࡞ࡗ࡚࠸
ࡿ࡜⪃࠼ࡽࢀࡿࠋ࣭࢔࢜ࢶࣛ࢝ࢶ࢜ࢻࣜ ௒ᅇࡢㄪᰝ࡛ࡣࠊᕢ❧ࡕ㛫㝿࡜⪃࠼ࡽࢀࡿᗂ㫽࡜ᢪ༸୰ࡢಶయࡀぢࡽࢀࡓࡀࠊᏤ
໬┤ᚋࡢ㞮ࡸ⥥⩚ࢆṧࡋࡓᮍᡂ⇍࡞㞮ࡣほᐹࡉࢀ࡞࠿ࡗࡓࠋࡇࡢࡇ࡜࠿ࡽࠊᮏ✀ࡣ⛅࠿ࡽ᫓ࡀ⦾Ṫᮇࡢ୰ᚰ࡜࡞ࡗ࡚࠸ࡿࡶࡢ࡜⪃࠼ࡽࢀࡿࠋᾏᓊ࡛ࡣ 62 ಶయࡢᡂ㫽ࢆྵࡴ㞟ᅋࡀほᐹࡉࢀࡓࡀࠊࡇࢀࡣࡇࢀࡲ࡛࡟すஅᓥ࡛ほᐹࡉࢀࡓ࢔࢜ࢶࣛ࢝ࢶ࢜
ࢻࣜࡢ㞟ᅋ࡜ࡋ࡚ࡣ᭱኱ࡢࡶࡢ࡛࠶ࡿࠋ࢔࢜ࢶࣛ࢝ࢶ࢜ࢻࣜࡣ 1991 ᖺ࡟ほᐹࡉࢀ࡚௨ᚋࠊ⦾Ṫಶయᩘࡀቑຍഴྥ࡟࠶ࡿ࡜⪃࠼ࡽࢀࡿࠋᮏ✀ࡣ◁ᆅ࡛ᕢᮦࢆ౑⏝ࡏࡎ࡟Ⴀᕢࡍࡿࡇ࡜࠿ࡽࠊすஅᓥ࡛ࡣᄇⅆᚋ࡟᪂ࡓ࡞ᾏᓊࡀቑຍࡋࡓࡇ࡜࡛Ⴀᕢྍ⬟࡞⏕ᜥᆅࡀቑຍࡋࡓ࡜ゝ࠼ࡿࠋ ࢔࢜ࢶࣛ࢝ࢶ࢜ࢻࣜࡣᅜෆ࡛ࡣすஅᓥࡢ௚࡟ᑤ㛶ㅖᓥ࡛ࡢࡳ⦾Ṫࡀ☜ㄆࡉࢀ࡚− 89 −࠸ࡿࠋ༡ᑠᓥ࡛ࡣ 2001 ᖺ࡟ࡣ 107 ಶయࡢᡂ㫽ࡀ☜ㄆࡉࢀࠊ໭ᑠᓥ࡛ࡣ 2002 ᖺ࡟⣙
50 ࡘࡀ࠸ࡢ⦾Ṫࡀ☜ㄆࡉࢀ࡚࠸ࡿ㸦Ἑ㔝࣭Ỉ㇂ࠊ2017㸧ࠋᑤ㛶ㅖᓥ࡛ࡣ 1970 ᖺ௦࡟⏕ᜥࡀ☜ㄆࡉࢀ࡚࠿ࡽ⦾Ṫᆅࡀᣑ኱ഴྥ࡟࠶ࡾ㸦Ἑ㔝࣭Ỉ㇂ࠊ2017㸧ࠊすஅᓥࡶྠࡌഴྥࡀ࠶ࡿ࡜ゝ࠼ࡿࠋ࣭ࢡࣟ࢔ࢪࢧࢩ ௒ᅇࡢㄪᰝ࡛ࡣᩘⓒಶయࢆྵࡴ⩌ࢀࡣほᐹࡉࢀࡓࡶࡢࡢࠊ⦾Ṫ୰ࡢಶయࡣぢࡽࢀ࡞࠿ࡗࡓࠋࡓࡔࡋࠊ༡す὾࡛༸Ẇࡀぢࡘ࠿ࡾࠊࡲࡓᮍᡂ⇍࡞ᗂ㫽ࡢ㦵ࡀከࡃぢࡘ࠿ࡗࡓࡇ࡜࠿ࡽࠊᮏ✀ࡣすஅᓥ࡛ከᩘࡀ⦾Ṫࡋ࡚࠸ࡿ࡜⪃࠼ࡽࢀࡿࠋ⢄ᒣ㸦1930㸧ࡣᮏ✀ࡢᑠ➟ཎ࡛ࡢ⦾Ṫᮇࢆ 4 ᭶ࠥ11 ᭶࡜ࡋ࡚࠸ࡿࠋ⌧ᅾࡢすஅᓥ࡛ࡣࠊࢡࣟ࢔ࢪࢧ
ࢩࡣࡼࡾ᪩࠸᫬ᮇ࡟⦾Ṫࡋࠊ8 ᭶ࡲ࡛࡟ᕢ❧ࡕࢆ⤊࠼࡚࠸ࡿࡶࡢ࡜⪃࠼ࡽࢀࡿࠋᮏ✀ࡢᗂ㫽ࡢ㦵ࡣᪧᓥୖ࡛ぢࡘ࠿ࡗࡓࡇ࡜࠿ࡽࠊᪧᓥࡀ⦾Ṫᆅ࡜ࡋ࡚฼⏝ࡉࢀ࡚࠸ࡿ
ྍ⬟ᛶࡀ࠶ࡿࠋࡓࡔࡋࠊ࢝ࢶ࢜ࢻࣜࡀᕢᮦ࡜ࡋู࡚ᆅⅬ࠿ࡽ㐠ࢇ࡛ࡁࡓྍ⬟ᛶࡶ࠶ࡿࡓࡵࠊ⦾Ṫሙᡤࡣ≉ᐃ࡛ࡁ࡞࠸ࠋ
࣭࢜࢜࢔ࢪࢧࢩ ௒ᅇࡢㄪᰝ࡛ࡣࠊ࢜࢜࢔ࢪࢧࢩࡢ⦾Ṫ࡟㛵ࡍࡿドᣐ࡜ࡋ࡚ࡣࠊ㞮 1 ಶయࡀほᐹࡉࢀࡓࡢࡳ࡛࠶ࡿࠋ2004 ᖺ 7 ᭶ 10 ᪥࡟すஅᓥ࡛⾜ࢃࢀࡓㄪᰝ࡛ࡣࠊ⥥⩚ࡢṧࡿᮍ⇍࡞㞮࠿ࡽ㣕⩧ྍ⬟࡞ᕢ❧ࡕ㞮ࡲ࡛ᵝࠎ࡞ẁ㝵ࡢ㞮ࡀ☜ㄆࡉࢀ࡚࠸ࡿࠋ࢜࢜࢔ࢪࢧࢩ
ࡣ 38ࠥ40 ᪥࡛ᕢ❧ࡘࡓࡵ㸦Cooper, 2006㸧ࠊ9 ᭶ࡢㄪᰝ࡛㞮ࡀ 1 ಶయࡋ࠿ぢࡘ࠿ࡽ࡞࠿ࡗࡓࡢࡣࠊ᪤࡟⦾Ṫᮇࡀ࡯ࡰ⤊஢ࡋ࡚࠸ࡓࡓࡵ࡜⪃࠼ࡽࢀࡿࠋ࣭࣮࢜ࢫࢺ࣑ࣥ࢘ࢶࣂ࣓ ᑠ➟ཎㅖᓥ࡟࠾ࡅࡿᮏ✀ࡢ⦾Ṫᮇࡣ 10 ᭶ࠥ4 ᭶࡜ࡉࢀ࡚࠸ࡿ㸦⢄ᒣࠊ1930㸧ࠋ௒ᅇࡢㄪᰝ࡛ࡣ཰ᣠࡋࡓ㦵࡟ከᩘࡢ࣮࢜ࢫࢺ࣑ࣥ࢘ࢶࣂ࣓ࡢ㦵ࡀⓎぢࡉࢀࡿ࡜ඹ࡟ࠊ㡢ኌグ㘓࠿ࡽ 2016 ᖺ෤ࠊ2017 ᖺ෤࡟ከᩘࡀ㣕᮶ࡋ࡚࠸ࡿࡇ࡜ࡀ᫂ࡽ࠿࡟࡞ࡗࡓࠋ
ࡲࡓࠊ㡢ኌࡣ 11 ᭶ࠥ5 ᭶࡟㛗ᮇ࡟ரࡾグ㘓ࡉࢀ࡚࠸ࡓࡇ࡜࠿ࡽࠊ᪤࡟⦾Ṫࢆ෌㛤ࡋ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿࠋࡓࡔࡋࠊᗂ㫽ࡢ㦵ࡸ㞮ࡢṚయࡣぢࡘ࠿ࡗ࡚࠾ࡽࡎࠊ⦾Ṫಶయࡀ࠸࡚ࡶᩘࡣᑡ࡞࠸࡜⪃࠼ࡽࢀࡿࠋ໭◲㯤ᓥ࡛ࡣ෤࡟⦾Ṫࡍࡿ࣮࢜ࢫࢺ࣑ࣥ࢘ࢶࣂ࣓ࡣ᫓࡟⦾Ṫࡍࡿࢡ࣑ࣟ࢘ࢶࣂ࣓࡜Ꮨ⠇ࢆ㐪࠼࡚ྠࡌᕢ✰ࢆ฼⏝ࡋ࡚࠸ࡓ࡜ࡉࢀࡿ㸦㯮⏣ࠊ1975㸧ࠋすஅᓥ࡛ࡣᮏ✀࡜࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜࡢ⦾ṪᮇࡀᏘ⠇ⓗ࡟㏫࡛࠶ࡿࡓࡵࠊྠࡌᕢ✰ࢆ౑⏝ࡋ࡚࠸ࡿྍ⬟ᛶࡀ࠶ࡿࠋ࣭ࡑࡢ௚ࡢ㫽㢮 2013 ᖺࡢᄇⅆ๓࡟⦾Ṫࡀ☜ㄆࡉࢀ࡚࠸ࡓ✀ࡢ୰࡛ࠊࢭࢢࣟ࢔ࢪࢧࢩࡣ௒ᅇࡢㄪᰝ࡛ࡣ⦾Ṫࡣ☜ㄆࡉࢀ࡞࠿ࡗࡓࠋ༡㫽ᓥࡸ㐣ཤࡢすஅᓥ࡛ࡣࢭࢢࣟ࢔ࢪࢧࢩࡢ⦾Ṫࡣ− 90 −

7 ᭶ࡲ࡛࡟࡯ࡰ⤊ࢃࡗ࡚࠸ࡿࡓࡵ㸦ᕝୖ࡯࠿ࠊ2005㸧
ࠊ௒ᅇࡢㄪᰝࡀ⾜ࢃࢀࡓ 9 ᭶ࡣ⦾Ṫᮇ࠿ࡽእࢀ࡚࠸ࡓࡶࡢ࡜⪃࠼ࡽࢀࡿࠋ 㝣㫽࡜ࡋ࡚ࡣ࢖ࢯࣄࣚࢻࣜࠊࢶࣂ࣓ࠊࢩࣟࣁࣛࠊࣄࢱ࢟⛉ࡢ 1 ✀ࡀぢࡘ࠿ࡗࡓࠋ
࢖ࢯࣄࣚࢻࣜࡣすஅᓥ࡟᭱ࡶ㏆࠸ᑠ➟ཎ⩌ᓥ࡟ᗈࡃ⦾Ṫࡋ࡚࠸ࡿࡓࡵࠊࡇࡇ࠿ࡽ⛣ືࡋ࡚ࡁࡓྍ⬟ᛶࡀ㧗࠸ࠋࡑࡢ௚ࡢ㝣㫽ࡣΏࡾ࡛㣕᮶ࡋࡓࡶࡢ࡜⪃࠼ࡽࢀࡿࠋ
࣭ᾏ㫽ࡢᶵ⬟ ᾏ㫽ࡣᾏ୰ࡢ⏕≀ࢆ㣗≀࡜ࡋ࡚࠸ࡿࡓࡵࠊ㝣ୖ⏕ែ⣔࡟౫Ꮡࡏࡎ࡟⦾Ṫࡍࡿࡇ࡜ࡀྍ⬟࡛࠶ࡿࠋࡇࡢࡓࡵࠊ᪂ࡓ࡟࡛ࡁࡓ㝣ᆅ࡟᳜≀ࡸ᪻⹸࡞࡝ࡀ㐍ฟࡋ࡚࠸࡞ࡃ࡜ࡶࠊႠᕢ࡟㐺ࡋࡓ≀⌮⎔ቃࡉ࠼࠶ࢀࡤ⦾Ṫࢆࡣࡌࡵࡿࡇ࡜ࡀ࡛ࡁࡿࠋ௒ᅇࡢㄪᰝ࡛ࡣࠊ᳜≀ࡀࡲࡔ㐍ฟࡋ࡚࠸࡞࠸すஅ὾ࠊ໭すྎᆅࠊ༡す὾࡟࠾࠸࡚ᐇ㝿࡟ከᩘࡢᾏ㫽ࡀ⦾Ṫࡋ࡚࠸ࡿࡇ࡜ࡀ☜ㄆࡉࢀࡓࠋ ᾏ㫽ࡣ⏕ែ⣔ࡢ୰࡛ከࡃࡢᶵ⬟ࢆᢸࡗ࡚࠸ࡿࠋᾏ㫽ࡣᾏ࡛᥇㣗ࡋ࡚㝣࡛᤼ἥࢆࡍࡿࡇ࡜࡛ࠊ❅⣲ࡸࣜࣥ࡞࡝ࡢᰤ㣴ሷࢆ㝣ୖ࡟౪⤥ࡍࡿ࡜࡜ࡶ࡟ࠊᅵተ pH ࡞࡝࡟ᙳ㡪ࢆ୚࠼ࡿࡇ࡜ࡀ▱ࡽࢀ࡚࠸ࡿ㸦Ellis, 2005㸧ࠋ᤼ἥ≀ࡔࡅ࡛࡞ࡃࠊ⦾Ṫᆅ࡟ࡣྤࡁᡠࡋࡸ㫽ࡢṚయ࡞࡝ࡶ᭷ᶵ≀࡜ࡋ࡚౪⤥ࡋࠊࡇࢀࡀศゎ⪅࡜࡞ࡿ⠇㊊ື≀ࡢ㣗≀࡜࡞ࡗ࡚࠸ࡿࠋࡲࡓࠊ㋃ᅽ࡟ࡼࡿ᧠஘࡛᳜≀ࡢ✀ᵓᡂ࡟ᙳ㡪ࢆ୚࠼ࡿࡇ࡜ࡶ▱ࡽࢀ࡚࠸ࡿ㸦Ellis, 2005㸧ࠋ࢝ࢶ࢜ࢻࣜࡸ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜࡣ௜╔ᆺࡢ✀Ꮚᩓᕸ⪅࡜࡞ࡾࠊᓥ㛫࡛✀Ꮚᩓᕸࢆ⾜࠺㸦Aoyama et al., 2012㸧ࠋࡲࡓ࢝ࢶ࢜ࢻࣜࡣ✀Ꮚࡢࡘ࠸ࡓ≧ែࡢ᳜≀ࢆᕢᮦ࡜ࡋ࡚฼⏝ࡍࡿࡇ࡜ࡶ࠶ࡿࡓࡵࠊᓥෆ࡛ࡢ✀Ꮚᩓᕸ⪅࡜ࡋ࡚ࡶᙺ❧ࡘ࡜⪃࠼ࡽࢀࡿࠋ࢜ࢼ࣑࢞ࢬࢼࢠࢻࣜ࡞࡝ࡢᕢࡣ⠇㊊ື≀ࡢ⏕ᜥᆅ࡜ࡋ࡚ࡶ฼⏝ࡉࢀ࡚࠸ࡿ㸦㑣㡲࡯࠿ࠊ2014㸧ࠋ࢝ࢶ࢜ࢻࣜࡣᾏᓊ࡟⁻╔ࡋࡓ᳜≀∦ࢆᕢᮦ࡜ࡋ࡚฼⏝ࡍࡿࡓࡵࠊෆ㝣࡟᭷ᶵ≀ࢆሁ✚ࡍࡿᶵ⬟ࡶ࠶ࡿ࡜ゝ࠼ࡿࠋ ࢫࣝࢶ࢙࢖ᓥ࡛ࡣᾏ㫽ࡢ⦾Ṫᆅࡀᗈࡀࡗࡓᚋ࡟᳜≀ࡢ✀ᩘࡀᛴቑࡋࡓࡀࠊࡇࢀࡣᾏ㫽࡟ࡼࡿ✀Ꮚᩓᕸ࡜ᰤ㣴ሷ౪⤥ࡢຠᯝ࡜⪃࠼ࡽࢀ࡚࠸ࡿ㸦Magnússon et al., 2014㸧ࠋすஅᓥ࡛ࡶᾏ㫽ࡀ⦾Ṫᆅࢆᣑ኱ࡍࡿࡇ࡜ࡀࡁࡗ࠿ࡅ࡜࡞ࡾ᳜≀ࡸ⠇㊊ື≀ࡀศᕸࢆᣑ኱ࡋ࡚࠸ࡃᾏ㫽ඛ⾜ᆺ⏕ែ⣔ࡀᡂ❧ࡋ࡚࠸ࡃྍ⬟ᛶࡀ࠶ࡿࠋ࣭ಖ඲ୖࡢᥦゝ ࢜࢜࢔ࢪࢧࢩ࡜࢔࢜ࢶࣛ࢝ࢶ࢜ࢻࣜࡣᅜෆ࡛ࡣすஅᓥ࡜ᑤ㛶ㅖᓥ࡛ࡢࡳ⦾Ṫࡋࠊࡑࡢ⦾Ṫศᕸࡢ໭㝈࡜࡞ࡗ࡚࠸ࡿࠋ⎔ቃ┬ࡢࣞࢵࢻࣜࢫࢺ࡛ࡣ࢜࢜࢔ࢪࢧࢩࡣ⤯⁛༴᝹ II 㢮㸦VU㸧
ࠊ࣮࢜ࢫࢺ࣑ࣥ࢘ࢶࣂ࣓ࡣ‽⤯⁛༴᝹㸦NT㸧࡟ᣦᐃࡉࢀ࡚࠸ࡿ㸦⎔ቃ┬ࠊ2014㸧ࠋすஅᓥࡣᾏ㫽⦾Ṫᆅ࡜ࡋ࡚㔜せ㔝㫽⏕ᜥᆅ㸦IBA㸧࡟ࡶᣦᐃࡉࢀ࡚࠸
ࡿࠋ௨ୖࡢࡇ࡜࠿ࡽࠊすஅᓥࡣ⛥ᑡ࡞ᾏ㫽ࡢ⦾Ṫᆅ࡜ࡋ࡚㧗࠸ಖ඲ୖࡢ౯್ࢆᣢࡘࠋ すஅᓥ࡟ࡣᄇⅆ࡟ࡼࡾ᪂ࡓ࡞㝣ᆅࡀᗈࡃฟ⌧ࡋࡓࠋྠᵝࡢ౛࡜ࡋ࡚࢖ࣥࢻࢿࢩ࢔
ࡢࢡࣛ࢝ࢱ࢘ᓥࠊ࢔࢖ࢫࣛࣥࢻࡢࢫࣝࢶ࢙࢖ᓥࠊ࢔࣮ࣜࣗࢩࣕࣥิᓥࡢ࢝ࢧࢺࢳᓥ

− 91 −࡞࡝ࡀ࠶ࡿࠋᓥࡢ⏕ែ⣔ࡢᡂ❧ࣉࣟࢭࢫࡢゎ᫂ࡣᓥᕋ⏕≀Ꮫ࡟࠾ࡅࡿ㔜せ࡞ㄢ㢟ࡢ
1 ࡘ࡛࠶ࡾࠊࡇࡢࡼ࠺࡞ሙᡤࡣ᳨ドࡢࡓࡵࡢ⮬↛ࡢᐇ㦂ሙ࡜࡞ࡿࠋࡋ࠿ࡋࠊࡇࢀࡽࡢඛ⾜஦౛ࡣ⏕≀ࡢ౪⤥※࡜࡞ࡿ㞄ࡢᓥࡸ኱㝣࠿ࡽ 20km ௨ୗࡋ࠿㞳ࢀ࡚࠾ࡽࡎࠊᏙ❧ࡋࡓᾏὒᓥ࡟࠾ࡅࡿ⌧㇟ࢆ෌⌧ࡍࡿࡇ࡜ࡣ㞴ࡋ࠸ࠋ୍᪉࡛すஅᓥࡣᴟᗘ࡟Ꮩ❧ࡋ࡚࠸ࡿࡓࡵࠊࣁ࣡࢖ࡸ࢞ࣛࣃࢦࢫࠊᑠ➟ཎࡢࡼ࠺࡞ᾏὒᓥ࡟࠾ࡅࡿࣉࣟࢭࢫࢆ෌⌧࡛ࡁࡿᕼ᭷࡞ሙᡤ࡜࡞ࡾ࠼ࡿࠋᾏὒᓥ࡛ࡣࡋࡤࡋࡤᾏ㫽ࡀ༟㉺ࡋ࡚࠾ࡾࠊࡑࡢከᵝ࡞ᶵ⬟ࡀ⏕ែ⣔ࡢᡂ❧ࣉࣟࢭࢫ࡟኱ࡁ࡞ᙺ๭ࢆᯝࡓࡍྍ⬟ᛶࡀ㧗࠸ࠋࡇࡢᓥࡣ࡯࡜ࢇ࡝እ᮶⏕≀ࡀศᕸࡋ࡚࠾ࡽࡎࠊࡲࡓ㏆ᖺࡣேࡢᙳ㡪ࡶᑡ࡞ࡃࠊேⅭ᧠஘ࡢ࡞࠸ཎ⏕≧ែࡢࣉࣟࢭࢫࡀ⥔ᣢࡉࢀ࡚࠸ࡿ࡜ゝ࠼ࡿࠋ௒ᚋࡶேⅭᙳ㡪ࢆᴟຊ᤼㝖ࡋࠊ⮬↛࡟㏆࠸≧ែࢆಖࡘࡇ࡜࡛ࠊᓥᕋ⏕≀ᏛࡢⓎᒎ࡟኱ࡁࡃ㈉⊩ࡍࡿ࡜⪃࠼ࡽࢀࡿࠋ すஅᓥࡣᄇⅆ๓ࡢᪧᓥࡢ⠊ᅖࡀୡ⏺⮬↛㑇⏘ᆅᇦ࠾ࡼࡧ⮬↛බᅬἲࡢ≉ูಖㆤᆅ༊࡟ྵࡲࢀ࡚࠸ࡿࠋࡋ࠿ࡋࠊ᪂ࡓ࡞㝣ᆅࡣࡑࡢ⠊ᅖ࡟ྵࡲࢀࡎࠊಖㆤᢸಖᥐ⨨ࡀ࡜ࡽࢀ࡚࠸࡞࠸ࠋࡇࡢࡓࡵࠊ᪩ᛴ࡟ἲⓗ࡞ಖ඲ᥐ⨨ࢆㅮࡎࡿࡇ࡜ࡀᚲ㡲࡛࠶ࡿࠋ ௒ᅇࡢㄪᰝ࡟ࡼࡾࠊ᪂ࡓ࡞㝣ᆅ࡟ከᩘࡢᾏ㫽ࡀ▷ᮇ㛫࡛㐍ฟࡋ࡚࠸ࡿࡇ࡜ࡀ᫂ࡽ
࠿࡟࡞ࡗࡓࠋ୍᪉࡛すஅᓥࡣ 2015 ᖺ࡟኱つᶍ࡞ᄇⅆࡀ཰ࡲࡗࡓᚋ࡟ࡶࠊ2017 ᖺ 4
᭶ࠊ2018 ᖺ 7 ᭶ࠊ2019 ᖺ 12 ᭶࡟෌ᄇⅆࡋ࡚࠾ࡾࠊᆅᙧࡢኚ໬ࡀ᩿⥆ⓗ࡟⥆࠸࡚࠸ࡿࠋ௒ᚋ 10 ᖺ⛬ᗘࡢ㛫ࡣᾏ㫽ࡢศᕸࡀ኱ࡁࡃኚ໬ࡍࡿ࡜ண᝿ࡉࢀࠊ⏕ែ⣔ኚ໬ࢆṇ☜࡟ᢕᥱࡍࡿࡓࡵ࡟ࡣࠊᙜ㠃ࡣᑡ࡞ࡃ࡜ࡶ 1 ᖺ࡟ 1 ᗘࡣㄪᰝࡍࡿࡇ࡜ࡀᮃࡲࡋ࠸ࠋࡓࡔࡋࠊㄪᰝ㢖ᗘࡀ㧗ࡲࢀࡤ⏕ែ⣔࡬ࡢᙳ㡪ࡶᠱᛕࡉࢀࡿࡓࡵࠊUAV ➼ࢆ᭷ຠά⏝ࡋ᧠஘ࢆ᭱ᑠ㝈࡟ᢚ࠼࡚ㄪᰝࡍࡿࡇ࡜ࡀồࡵࡽࢀࡿࠋࡲࡓࠊ㫽㢮ࡣᏘ⠇࡟ࡼࡾศᕸ≧ἣࡀ኱ࡁࡃኚࢃࡿࡓࡵࠊ෤ࡸ᫓࡞࡝␗࡞ࡿ᫬ᮇࡢୖ㝣ㄪᰝࡶᚲせ࡛࠶ࡿࠋ㸳㸬ㅰ㎡ ᮏ◊✲ࡢᡂᯝࡣࠊ⎔ቃ┬ࡀ୺ദࡋ⮬↛⎔ቃ◊✲ࢭࣥࢱ࣮ࡀㄳࡅ㈇ࡗ࡚ᐇ᪋ࡉࢀࡓ
すஅᓥ⥲ྜᏛ⾡ㄪᰝ࡟ࡼࡿࡶࡢ࡛࠶ࡿࠋㄪᰝࡢᐇ᪋࡟࠶ࡓࡗ࡚ࡣࠊ⎔ቃ┬ࠊᯘ㔝ᗇࠊᑠ➟ཎᮧࠊᑠ➟ཎ⁺ᴗ༠ྠ⤌ྜ➼ࡢྛ㛵ಀᶵ㛵࡟ከ኱࡞౽ᐅࢆᅗࡗ࡚࠸ࡓࡔ࠸ࡓࠋ⌧ᆅㄪᰝࢆ⾜࠺ୖ࡛ࡣࠊ⥲ྜㄪᰝ࡟ཧຍࡋࡓྛศ㔝ࡢㄪᰝ㝲ဨࡢ᥼ຓࢆ࠸ࡓࡔ࠸ࡓࠋ≉࡟᳜≀ࡢ᥇㞟࡛ࡣୖᲄ㝯ᚿ࡜ᘅ⏣ ඘Ặ࡟ࠊ⠇㊊ື≀ࡢ᥇㞟࡛ࡣᓊᮏᖺ㑻Ặ࡜᳃ⱥ❶Ặ࡟ࠊUAV ࡟ࡼࡿㄪᰝ࡛ࡣᒸᮧᘻᶞẶ࡟ࠊኪ㛫ㄪᰝ࡛ࡣᕝཱྀ኱ᮁẶ࡜㧗ᕊ᫓ኵẶ࡟༠ຊࢆ࠸ࡓࡔ࠸ࡓࠋࡇࡇ࡟῝࠸ឤㅰࡢពࢆ⏦ࡋୖࡆࡓ࠸ࠋ
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OGASAWARA RESEARCHSUMMARY

Avifauna of Nishinoshima Island, the Ogasawara Islands, in 2019

Kazuto KAWAKAMI1*& Yusuke OYAMADA2
1. Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687,
Japan
2. Japan Wildlife Research Center, 3-3-7 Kotobashi, Sumida, Tokyo 130-8606, Japan.
* kazzto@ffpri.affrc.go.jp (author for correspondence)

In September 2019, a field survey was conducted to determine the current status ofavifauna on Nishinoshima, a volcanic island that is part of the Ogasawara Islands.
Nishinoshima has been broadly covered with lava flows due to a series of eruptions whichbegan in 2013. Evidence of breeding for five seabird species (Brown Booby, Masked Booby,Wedge-tailed Shearwater, Brown Noddy, and Greater Crested Tern) was confirmed near asmall remnant of the former island. The largest number of sightings was for the brownbooby, and approximately 400 chicks were detected around the remnant area. This species
has expanded its breeding area into newly established ground created by the eruptions. The
breeding season of this species became longer than on the other islands of the Ogasawara
Islands. This might be due to the high density of the breeding population caused by reduced
breeding habitat due to lava flows. Since seabirds have several important ecological functions,such as seed dispersal and nutrient input, their range expansion to new habitats promotes theestablishment of ecosystems.
Key words
Brown Booby, Conservation, Ecological function, Ogasawara Islands, Seabird− 94 −