The Ecological Society of Japan (Japanese Journal of Conservation Ecology) 17 : (2012) 1, * Changes in the understory vege

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1 (Japanese Journal of Conservation Ecology) 17 : (2012) 1, * Changes in the understory vegetation due to the decrease in sika deer density in Akan National Park, eastern Hokkaido, Japan Yoshihiro Inatomi 1, *, Hiroyuki Uno 1, Yachiyo Takashima 2, Kazuyuki Onimaru 3, Masami Miyaki 4 and Koichi Kaji 5 1 Institute of Environmental Sciences, Hokkaido Research Organization, 2 Hokkaido University of Education Kushiro Campus, 3 Bihoro Museum, 4 Rakuno Gakuen University, 5 Faculity of Agriculture, Tokyo University of Agriculture and Technology ± 10.7 /km ± 2.5 /km Abstract: We conducted aerial surveys of the sika deer (Cervus nippon yesoensis) population in Akan National Park, eastern Hokkaido, Japan, between 1993 and 2009 to assess the effects of doe hunting and managed culls on deer density. We also surveyed the cover and height of understory plants in exclosure and control sites between 1995 and 2010 to examine changes in the understory vegetation in response to decreasing deer density. The aerial survey showed that deer density decreased from 27.1 ± 10.7 deer/km 2 in 1993 to 9.5 ± 2.5 deer/km 2 in The data suggest that hunting females and culling herds caused the decrease in deer density, as the population began to decline after doe hunting was allowed in 1994, decreased sharply in response to the deregulation of doe hunting in 1998, and was maintained at a low level after 1999 when managed culls were begun. We analyzed the cover and height of 15 palatable and two unpalatable plants in the understory vegetation. In the sites where hunting and culls were conducted, the cover or height of three palatable plants (Sasa senanensis, Thalictrum ssp., and Trillium ssp.) increased, and an unpalatable plant (Senecio cannabifolius) disappeared in parallel with decreasing deer density. This suggests that management of deer density has allowed understory vegetation to recover by reducing browsing pressure. We conclude that population control of sika deer is an effective measure to foster recovery of understory vegetation damaged by high browsing pressure from deer. Keywords: aerial survey, cull, female hunting, palatable plants, unpalatable plants * Eastern Hokkaido Wildlife Research Station, Institute of Environmental Sciences, Hokkaido Research Organization, 2-54, Urami 2, Kushiro, Hokkaido , Japan inatomi@hro.or.jp

2 Rooney 2001 Rooney and Waller 2003 Cervus nippon Akashi and Nakashizuka 1999 Yokoyama et al. 2001Yokoyama and Shibata 1998 Nomiya et al C. nippon yesoensis Empetrum nigrum L. var. japonicum K. Koch Sasa borealis (Hack.) Makino et Shibata , 2008 Sasa nipponica (Makino) Makino et Shibata Itô and Hino 2005 Kumar et al Uno and Kaji Kaji et al Uno et al 調査地域の概要 87.1 km m mm cm

3 Abies sachalinensis (F.Schmidt) Mast. Picea jezoensis (Siebold et Zucc.) Carrière Ulmus davidiana Planch. var. japonica (Rehder) Nakai Quercus crispula Blume Acer pictum Thunb. ex Murray ssp. mono (Maxim.) Ohashi Tilia japonica (Miq.) Simonk Kaji et al 航空機調査 Uno et al Uno et al km km km km 2 80 km/h 100 m 1 km /km SCF 0 Gasaway et al Uno et al n 0 w k k v k 9 1 林床植生調査 A B D 3 E F G 1 C 1 10m 20m B C E F G 3 m 2 /ha E G 2009 A C B 1 2m 2m 1m 1m cm

4 m 2 /ha A B C D E F G Senecio cannabifolius Less. Pteridium aquilinum (L.) Kuhn 2007 Thalictrum minus L. var. hypoleucum (Siebold et Zucc.) Miq. Trillium camschatcense Ker Gawl. Thalictrum baicalense Turcz. ex Ledeb. Thalictrum sachalinense Lecoy. Trillium tschonoskii Maxim. Thalictrum spp. Trillium spp. I II III エゾシカ生息密度の推移 ± 10.7 /km 2 ± ± 5.0 /km ± 8.8 /km /km /km ± 2.0 /km ± 2.5 /km 2 林床植生の変化 Sasa senanensis (Franch. et Sav.) Rehder A F 18.0 I A I II 5 III I II A Carex sachalinensis F. Schmidt var. sachalinensis I III

5 22002 Uno et al n 0 SCF 0 v k w k k=1 k=2 k=3 k=4 k=5 k=6 k=7 k=8 k=9 k=1 k=2 k=3 k=4 k=5 k=6 k=7 k=8 k=9 1993/ D E I F I B D E III 5 B D II B D Pachysandra terminalis Siebold et Zucc. Carex pilosa Scop. C I II Petasites japonicus (Siebold et Zucc.) Maxim. subsp. giganteus (G.Nicholson) Kitam. 50 II I G F G A Impatiens nolitangere L. E Cirsium kamtschaticum Ledeb. ex DC. C E F F G C E A I A II II 2005 G A II III 189

6 3 I II III

シカ密度の低下に伴う林床植生の変化図 4 A 区の対照区における林床植生の変化 a クマイザサとオシダが優占し全体の植被率は低かった 1995 年 8 月撮影 b サハリンイトスゲが高い被度で優占する林床に推移しクマイザサは消失したまたトドマツの稚樹もみられた 2009 年 8 月撮影図 5 E 区の対照区における林床植生の変化 a エゾイラク

排除区におけるエンレイソウ属 A 区の植物高の増加に与えた影響幅は対照区に比べてシカ排除区で大きかった対照区航空機調査の結果阿寒国立公園における 2008 年とにおけるエンレイソウ属 A 区は III 期に植物高が 2009 年におけるエゾシカの生息密度は 2001 年 2004 増加傾向を示した一方で被度に顕著な変化はみられな年より低い傾向を示した図 2

7 シカ密度の低下に伴う林床植生の変化図 4 A 区の対照区における林床植生の変化 a クマイザサとオシダが優占し全体の植被率は低かった 1995 年 8 月撮影 b サハリンイトスゲが高い被度で優占する林床に推移しクマイザサは消失したまたトドマツの稚樹もみられた 2009 年 8 月撮影図 5 E 区の対照区における林床植生の変化 a エゾイラクサや不嗜好性植物のハンゴンソウが優占していた 1998 年 8 月撮影 b クサソテツとクマイザサが増加しハンゴンソウは消失した 2009 年 8 月撮影向を示したもののシカ排除区より増加の開始時期は遅考かったまた I 期の対照区とシカ排除区におけるカラ察マツソウ属 F 区の被度 III 期の対照区と I 期のシカメスジカ狩猟の解禁と個体数調整がエゾシカの生息密度排除区におけるエンレイソウ属 A 区の植物高の増加に与えた影響幅は対照区に比べてシカ排除区で大きかった対照区航空機調査の結果阿寒国立公園における 2008 年とにおけるエンレイソウ属 A 区は III 期に植物高が 2009 年におけるエゾシカの生息密度は 2001 年 2004 増加傾向を示した一方で被度に顕著な変化はみられな年より低い傾向を示した図 2 電波発信機を用いたかったエゾシカのテレメトリ調査では積雪条件によって越冬対照区とシカ排除区の双方に出現しどちらかの最大地を変える個体の存在が確認されている Uno and Kaji 被度が 5 以上を示した不嗜好性植物の被度及び植物高 2000 が 2008 年の阿寒湖アメダス観測所における最の推移を図 7 に示すハンゴンソウ E 区はシカ排深積雪深は 1993 年以降で最も少ない 75 cm 気象庁ホ除区の被度が非常に小さかったのに対し対照区ではームページ年 1996 年に 22.5 に達した後減少傾向を示し 2000 年 8 月 24 日確認だったため多くの個体が越冬地を変えに消失した図 5 ハンゴンソウ F 区はシカ排除生息密度が低くなった可能性が考えられるその一方で区で 2002 年対照区で 2001 年に消失した 2000 年の生息密度は前後年に比べて極端に高かった 191

8 3 5 A B C D E F G Thalictrum ssp Cardamine leucantha Trifolium repens 0.1 Impatiens noli-tangere Angelica sachalinensis var. sachalinensis Pleurospermum uralense 1.3 Sanicula chinensis Artemisia montana Cirsium kamtschaticum Picris hieracioides subsp. japonica Cardiocrinum cordatum var. glehnii 0.3 Polygonatum odoratum var. maximowiczii Trillium ssp Calamagrostis langsdorffii 3.0 Sasa senanensis Cynanchum caudatum Senecio cannabifolius

9 6 5 2Uno and Kaji cm km Kaji et al /km /km /km / km ± 2.5 /km Uno and Kaji

10 Kaji et al エゾシカ生息密度の低下に伴う林床植生の変化 Igota et al A 2 F I 1995 A F 3 D E I 3 F I B D E III 3 B D II 3 Noguchi and Yoshida 2004 B B II 3 D 3 194

11 F G A E C I 6 F I G II 6 A III 6 G A I 6 I F A 6 F I G II A B D E III 2010 Odocoileus virginianus Anderson 1994 Augustine and Frelich 1998 Koh et al A E I 3 6 E F II 7 F 2007 C C C 3 3 C 50 C Akashi 2009 Husheer et al

12 2007E F A Akashi N (2009) Simulation of the effects of deer browsing on forest dynamics. Ecological Research 24: Akashi N, Nakashizuka T (1999) Effects of bark-stripping by Sika deer (Cervus nippon) on population dynamics of a mixed forest in Japan. Forest Ecology and Management 113: Anderson RC (1994) Height of white-flowered trillium (Trillium grandiflorum) as an index of deer browsing intensity. Ecological Applications 4: Augustine DJ, Frelich LE (1998) Effects of white-tailed deer on populations of an understory forb in fragmented deciduous forests. Conservation Biology 12: (2007) (). 12: (2011) Cervus nippon. 16: Gasaway WC, DuBois SD, Reed DJ, Harbo SJ (1986) Estimating moose population parameters from aerial surveys. Biological Papers of University of Alaska 22: Husheer SW, Coomes DA, Robertson AW (2003) Longterm influences of introduced deer on the composition and structure of New Zealand Northofagus forests. Forest Ecology and Management 181: (1994). ( ) pp ,. Igota H, Sakuragi M, Uno H, Kaji K, Kaneko M, Akamatsu R, Maekawa K (2004) Seasonal migration patterns of female sika deer in eastern Hokkaido, Japan. Ecological Research 19: (2010). 15: Itô H, Hino T (2005) How do deer affect tree seedlings on a dwarf bamboo-dominated forest floor? Ecological Research 20: ( ) (2003).,. (1981). 8: Kaji K, Saitoh T, Uno H, Matsuda H, Yamamura K (2010) Adaptive management of sika deer populations in Hokkaido, Japan: Theory and practice. Population Ecology 52: Koh S, Bazely DR, Tanentzap AJ, Voigt DR, Silva ED (2010) Trillium grandiflorum height is an indicator of white-tailed 196

13 deer density at local and regional scales. Forest Ecology and Management 259: (1994). ( ) pp ,. Kumar S, Takeda A, Shibata E (2006) Effects of 13-year fencing on browsing by sika deer on seedlings on Mt. Ohdaigahara, central Japan. Journal of Forest Research 11: (2011). 16: (2005). 5: (2011). 61: (2003). 30: (2011). ( ). pp ,. Noguchi M, Yoshida T (2004) Tree regeneration in partially cut conifer-hardwood mixed forests in northern Japan: Role of establishment substrate and dwarf bamboo. Forest Ecology and Management 190: Nomiya H, Suzuki W, Kanazashi T, Shibata M, Tanaka H, Nakashizuka T (2002) The response of forest floor vegetation and tree regeneration to deer exclusion and disturbance in a riparian deciduous forest, central Japan. Plant Ecology 164: (1994). ( ) pp ,. (2007). 11: Rooney TP (2001) Deer impacts on forest ecosystems: A North American perspective. Forestry 74: Rooney TP, Waller DM (2003) Direct and indirect effects of white-tailed deer in forest ecosystems. Forest Ecology and Management 181: (2007) : (2008) 7. 90: (2010). 15: (2005). 10: (2004). 9: Uno H, Kaji K (2000) Seasonal movement of female sika deer in eastern Hokkaido. Mammal Study 25: Uno H, Kaji K (2006) Survival and cause-specific mortality rates of female sika deer in eastern Hokkaido, Japan. Ecological Research 21: (2007). 47: Uno H, Kaji K, Saitoh T, Matsuda H, Hirakawa H, Yamaura K, Tamada K (2006) Evaluation of relative density indices for sika deer in eastern Hokkaido, Japan. Ecological Research 21: (1995). 249: (1995). 52: Yokoyama S, Maeji I, Ueda T, Ando M, Shibata E (2001) Impact of bark stripping by sika deer, Cervus nippon, on subalpine coniferous forests in central Japan. Forest Ecology and Management 140: Yokoyama S, Shibata E (1998) The effects of sika-deer browsing on the biomass and morphology of a dwarf bamboo, Sasa nipponica, in Mt. Ohdaigahara, central Japan. Forest Ecology and Management 103:

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橡 PDF ( ) * Regeneration of many tree species by soil scarification under canopies -Relation between canopy openness and species richness- Hajime SATO ( )20 20 40 PAR30 0.5 1 (2) 1970 1993 1997 1996 1982 Hokkaido