1.日本の東北地方から西表島までの17地域の照葉樹林において,シイ属とタブノキ属,コナラ属アカガシ亜属の樹種の開芽時期を調べた.まず,千葉でスダジイとタブノキの芽ぶきの過程を調べた.これを基に,各地で観祭日における芽ぶきの状態からその樹種の開芽時期を推定した.
  2.シイ属の開芽時期は,西表島で12月下旬〜1月上旬,沖縄本島で2月中旬〜3月上旬,徳之島で3月下旬,屋久島で3月中旬,大隅半島で3月下旬〜4月下旬,奈良で4月下旬,房総半島で4月上旬〜下旬,宮城県名取で5月上旬〜中旬であった.タブノキ属,コナラ属アカガシ亜属の樹種の多くもシイ属とほぼ同時期に芽ぶいていた.これらの開芽時期は,諸文献の概略的な記録とも一致した.
  3.シイ属の開芽は,北ほど遅くなり,南北で約5カ月の時差がみられた。しかし,緯度の増加に対する開芽時期の遅れは北ほど小さかった.
  4.日本列島の照葉樹林の優占種群では,気候条件の地域的な違いに対し,種間での開芽の同調性はほぼ保たれたまま,開芽時期が北ほど遅れることが明かとなった.

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  1.日本列島では,12月〜5月にかけて南ほど早く,北ほど遅くシイ(スダジイとその亜種オキナワジイ)が開芽する.このようなシイの開芽時期と地域差をもたらす要因を,開芽直前の気温の面と遅霜,および年間同化量最大化の面から検討した.
  2.シイの開芽中とその直前の気温を各地で比較したところ,日平均,日最高,日最低気温とも本土と南西諸島との間で差が認められた.したがって,シイの開芽時期は,地域間で同一の暖かさの到来によって決まっているのではないと考えられる.
  3.温度-光合成関係と葉の成熟・老化過程を用いて年間の純同化量を求めるモデルを作成した.このモデルに日本各地の気温データを代入するシミュレーションをおこない,年間の純同化量が最大になる最適開芽時期を求めた.
  4.日本本土では,実際の開芽時期は降霜期間の終りと一致しており,最週開芽時期とは一致しなかった.霜の降りない南西諸島では,シミュレーションで得られた最適開芽時期と実際の開芽時期とは一致した.
  5.以上のことから,日本列島におけるシイの開芽時期は,同一の暖かさの到来によって決められているのではなく,霜の降りる地域では霜による被害を避けつつ,年間の同化量が最大になるように決められていると考えた.

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Owase District in Mie Prefecture, located on the south-east side of Kii Peninsula, is one of the wettest region in Japan. Annual precipitation in Owase city is more than 4,000 mm, and warmth index is 128.7℃・Month. Consequently, laurel forests have been able to develop on lowland and mountain slopes. Firstly, a phytosociological study was made of the laurel forests, which were classified into six community types : A, B, C, D, E and F. Pittosporum tobira community (A) is located on the seashore. Quercus phillyraeoides -Pittosporum tobira community (B) is on windy, steep slope, near the seashore. Quercus phillyraeoides - Dicarnopteris dicotoma community (C) is on sites with conditions similar to those of community (B). Castanopsis cuspidata var. sieboldii - Symplocos glauca community (D) and Castanopsis cuspidata - Photinia glabra community (E) are located from the seashore to lower elevations of mountainsides (<400m). On higher mountainsides (about 400〜700m) Quercus salicina - Cleyera japonica community (F) is found. Secondly, I investigated the relatioship between the six community types and site conditions. Owase District is a very wet region, but there are dry sites on the mountainsides where communities A, B and C are found. On less xeric sites, Communities D and E are distributed. On the basis of these results, the relationship between environmental gradient and community structure (complex sinusia) is discussed.

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Floristic composition was investigated in the Malus baccata var. mandshurica bush on the sand dunes along the Sea of Okhotsk, in eastern Hokkaido. A phytosociological association, Lonicero - Maletum baccatae, was newly recognized. Its characteristic species are Malus baccata var. mandshurica, Lonicera chrysantha var. crassipes and Sambucus sieboldiana var. miquelii. In the case of the M. baccata var. mandshurica bush, only Roso〜Maletum mandshuricae (Tatewaki 1961) Ohba, Miyawaki et Tx. 1973, has been reported. It belongs to Rosion rugosae Ohba, Miyawaki et Tx. Lonicero-Maletum baccatae lacks Rosa rugosa and Artemisia japonica, but it has many species common to the Angelico anomalae - Quercetum dentatae (Tatewaki 1961) Ohba, Miyawaki et Tx. 1973, the climax forest on coastal sand dunes. It also has many of the character and differential species of its upper unit. Thus Lonicero-Maletum baccatae belongs to Quercion dentatae Miyawaki et Yasushi Sasaki 1980. Fixation of trees in coastal sand dunes is difficult because of the severe environment as a dense sand dune vegetation cover, the strong sea wind and so on. Seeds of M. baccata var. mandshurica are dispersed by birds and can produce root-suckers, allowing it to grow in coastal sand dunes as a pioneer shrub.

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Butterfly assemblages were investigated using route census surveys, at Flowertown in Sanda from April to October, 1994. In order to evaluate the naturalness of vegetation through the species composition of butterflies, we proposed a butterfly index, which indicated the degree of naturalness of the habitat. The values of species diversity, averages of the butterfly index, and values calculated by the Bray-Curtis ordination method were calculated for eight vegetational conditions ; outside fragmented forest ; inside fragmented forest ; outside grassland ; inside grassland ; park ; detached house ; multiple dwelling house ; bare area. The results showed that the species diversity and butterfly index were highest in fragmented forests, and were lowest in the bare area. Ecological distribution of butterflies was classified into four types ; forest-type ; grassland-type ; park-type ; others. Many butterflies belonged to the forest-type classification, since there were many plant communities in the fragmented forests, such as Rhododendro macrosepali-Pinetum densiflorae, Quercetum variavili-serratae, Alnus japonica-Ligustrum obtusifolium Comm. Apanantho-Celtidetum japonicae, Querces acutissima Comm. etc. It seemes that fragmented forests are a very important habitat for butterflies, in spite of the small size of such forests. Butterfly assemblages at Flowertown were compared with other localities, including Mino Park, Hattori-ryokuchi Park, Osaka Castle Park, etc. Mino Park, Mt. Nijosan and Mt. Sanageyama were estimated to be at the secondary vegetational stage, while Osaka Castle Park, Nagai Park and Daisen Park were estimated to be at the urban stage. Although Flowertown was at the secondary vegetational stage in terms of butterfly fauna, it was at the residential-urban stage in terms of butterfly assemblages.

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土中営巣性の海鳥であるオオミズナギドリは,西太平洋の中緯度海域の島嶼を中心に集団繁殖している.日本では島嶼の照葉樹林や草地などで繁殖しているが,林床での営巣活動,夕方から早朝までの徘徊および移動,糞尿排泄などオオミズナギドリの諸行動は繁殖地の植生に様々な影響を与えていると考えられる.そこで三重県大島の照葉樹林(スダジイ-オオシマカンスゲ群集)においてオオミズナギドリの営巣が植生に及ばす影響を調査した.本調査地(大島)におけるオオミズナギドリの巣穴密度は低く(6.0±2.0/100^2),巣穴構造も発達したものではなかった.巣穴は根系の下(とくに大径木)に多く掘られ(62.2%),高密度営巣地である御蔵島では,巣穴がランダム分布するのに対し,大島では集中分布を示した.オオミズナギドリの営巣立地と非営巣立地の植生は変群集レベルで相違が見られ,大島のスダジイ-オオシマカンスゲ群集はアリドオシとヒサカキを区分種とするアリドオシ変群集(非営巣立地)とオオツヅラフジ,クズ,コウモリカズラ,ヤブミョウガ,キブシ,メジロホオズキ,ツクシキケマン,ツユクサを区分種とするオオツヅラフジ変群集(営巣立地)とに下位区分された.各変群集について生態的属性を比較した結果,両変群集の間にはヤブツバキクラス標徴種の比率,休眠型(地表植物および1年生植物),草本層の種数,高木層の植被率においてそれぞれ有意な差異が認められた.また営巣立地では,巣穴付近で植被率の著しい低下が生じる一方,ノイバラクラスの林縁植物の侵入および繁茂が見られるなど,オオミズナギドリの営巣活動による植生構造および種組成への影響が明らかにされた.三重県大島(低密度営巣地)と京都府冠島(高密度営巣地)の植生構造との比較により,オオミズナギドリの営巣立地選択性についての考察を試みた.

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