Yuri Maesako

内モンゴルのタルツールにおいて，遊牧生活と草地植生の変遷との関係をヒアリング調査から探るとともに、草原の植生調査とGPSによる地理情報調査により，衛星写真ALOSから植生評価を行い、生活様式と草原植生との関連性を検討した。ALOS衛星写真による植生評価はこれまでに行われていないことから，植生評価に対するALOS衛星写真の有効性についても論じた。

琵琶湖の固有性とタブノキ林の群集構造について解析し，滋賀県のタブノキ林の分布特性を明らかにした。とくに，カワウの影響により崩壊が著しい竹生島の時系列的植生変遷について言及した。

照葉樹林に侵入・拡大した外来樹木の個体および個体群の位置をＧＰＳで把握し、ＧＩＳ図を作成することによって、照葉樹林における外来種の拡散を定量的に明確にした。世界文化遺産でもある森林における外来種の量的把握に成功した論文として評価された。

奈良県下の保育所におけるアンケート調査から，環境領域における保育活動を分析し，大学の保育士養成機関における環境教育について論じた。

奈良県の社叢を事例に，植栽後64年経過した鎮守の森の植生構造を明らかにし，地域の森林保全としての社叢の意義を明らかにした。

奈良県の社叢を事例に，植栽後64年経過した鎮守の森の植生構造を明らかにし，地域の森林保全としての社叢の意義を明らかにした。

We investigated bark-stripping by Sika deer (Cervus nippon) in the forest at Nara Park, which is inhabited by more than 1200 deer. We found bark-stripping in 33.8% of 1041 trees more than 1.3m in height. Among the 39 tree species recorded in 10 areas, 31 species were found to suffer various degrees of bark-stripping. The species most preferred by the deer were Lagerstroemia indica, Viburnum awabuki, Podocarpus macrophyllus, and Pieris japonica, whereas those less preferred were Prunus mume, Carpinus tschonoskii, Ginkgo biloba, Quercus myrsinaefolia, Sapium sebiferum, Zelkova serrata, and Pinus thunbergii. The frequency distribution of trunk diameter at breast height (DBH) of trees suffering from bark-stripping indicated a reverse J-shaped distribution. However, bark-stripping was performed randomly within each species, regardless of DBH. This suggests that bark-stripping by Sika deer depends on bark preference rather than DBH size. In each plot, the proportion of non-preferred trees increased with increasing distance from the Kasugayama Forest Reserve and/or Wakakusayama Hill, and decreased with increasing distance from the urban areas. The relationship between the spatial environmental gradient and bark-stripping by Sika deer suggests that regional conservation is necessary for the management of vegetation and the high-density Sika deer population in Nara Park.

Pine trees,Pinus thunbergii,greater than 50 cm DBH(diameter at breast height )were investigated in the precints of Kofukuji Temple, a World Heritage site in Nara Park, Japan, to compare the structure of Pinus thubergii population in 1979 and 2005 and to re-evalute the tree landscape in the precincts of the temple.The DBH frequency distribution was a reverse J-shaped distribution; there were approximately the same number of pine trees as there were 26 years ago(83 individuals in 2005 versus 77 in 1979). However, the vitality of some pine trees tended to be poor;ca.30% apperred vigorous,while the remainder showed problems with growth. The tree landscape at Kofukuji Temple is discussed from the viewpoints of regional vegetation and culture.

Bark removal by sika deer Cervus nippon was observed by periodically providing potted trees along deer trails from spring through winter in Nara Park, Nara Pref., in central Japan. Potted trees used were Illicium religiosum and Ilex rotunda, which are known to be preferred by deer. Two types of bark removal were observed: gnawing and rubbing. Gnawing was done by males, females and fawns in all seasons, and the frequency was related with deer population density. Deer that barked trees by gnawing always ingested the scraped bark, and also tended to forage on twigs of the potted trees. Rubbing was done only by males during rutting season. These observations indicate that bark removal by gnawing is associated with feeding and bark removal by rubbing is related with rutting behavior by males.

The effects of burrow-nesting by streaked shearwaters (Calonectris leucomelas) on the growth and survival of Persea thunbergii seedlings was studied in a warm-temperate evergreen forest on Kanmurijima Island, Kyoto, central Japan. The author used 20 protected and unprotected plots to explore seedling survival and growth. The P. thunbergii seedlings that survived the disturbances of burrow nesters were significantly taller and had a larger leaf area than those of dead P. thunbergii seedlings. Seedlings of this species were found to have a small total leaf area, independent of the height growth, in comparison with seedlings of the same species in forest areas not used by streaked shearwaters. These results at the seedling stage suggest that there is a strong relationship between lower survivorship of P. thunbergii seedlings and the negative effects on seedling growth caused by burrow-nesting disturbances. This paper also discusses the conservation of the warm-temperate evergreen forest as suitable habitats for streaked shearwaters.

The initial growth of Persea thunbergii seedlings was studied at a rookery site of streaked shearwaters (burrow nesters) in evergreen broad-leaved forests on Kanmurijima Island and at a non-rookery site on Jajima Island in Kyoto, Japan. Seeds of P. thunbergii collected on Kanmurijima Island in August were experimentally sown in order to survey the initial growth of the seedling. The height of the first-year seedlings of P. thunbergii in a rookery site was found to be lower than that of first-year seedlings in a non-rookery site. The height for the first-year seedlings of P. thunbergii in protected plots significantly differed from the height in unprotected plots on Kanmurijima Island. The leaf area for the older seedlings (more than one year old) of P. thunbergii in a rookery site was conspicuously small in the P. thunbergii seedlings from different regions. The total area of leaves per seedling indicated a converse J-shaped frequency distribution for the P. thunbergii seedlings on Kanmurijima Island, but indicated a normal distribution for seedlings on Jajima Island and for those sown for the experiment. This result suggests that physical disturbance of burrow nesters causes a decrease in leaf area and height in the initial stage of P. thunbergii seedling growth.

ニホンジカの採食による植物への影響をシカの採食状況から評価した．これまで採食されなかったイズセンリョウが採食されはじめたという現象を定量的に明確にするための調査を行った．シカの個体群密度が高くなることにより，シカの餌シフトが生じていると考えられた．

The relationship between fraying by Sika deer (Cervus nippon TEMMINCK) and tree species preference was studied in a warm-temperate evergreen forest on Mt. Kasugayama, Japan. The forest was given as a World Heritage status in 1998. The proportion of trees frayed by deer among the total number of sampled trees (N=2351) was 2.6%. The height of lower limits of fraying on stems was 41.0±21.0cm (mean±SD), which was significantly different from lower limits of bark stripping (28.5±16.4cm). However, the height of upper limits was 83.9±23.3cm, which was not significantly different to upper limits of bark stripping (77.1±18.2cm). The relationship between fraying and DBH distribution is also discussed in this paper. Sixty-eight trees of 22 species (e. g. Abies firma, Podocarpus nagi, Illicum religiosum, Neolitsea asiculata) were found to be frayed among 2351 randomly sampled trees (H>1.3 m) of 55 species. It was found that bucks tend to prefer tree species which contain essential oil. This result suggests a relationship between fraying for territory and tree species preference, although fraying for the removal of velvet is generalized.

The ground vegetation of an evergreen broad-leaved Persea thunbergii-dominated forest on Kanmurijima Island has been heavily damaged by a ground-burrowing seabird, the streaked shearwater (Calonectris leucomelas). To clarify the effects of seabird trampling and burrowing on the recruitment of tree seedlings, 22 paired quadrats, protected and unprotected against seabirds, were laid out under various degrees of canopy coverage, ranging from heavy- to light-shade. Protection from seabird activities resulted in an increase in species richness of tree seedlings. Seabird activities had a significant effect on tree seedling diversity, while canopy coverage was shown to be important for herbaceous species diversity. Though seedling emergence of Persea thunbergii, the evergreen canopy dominant, was not affected by seabird activities and canopy coverage, that of Mallotus japonicus, a deciduous pioneer tree, was negatively affected by the both factors. Seabird activities and evergreen heavy-shade canopy negatively affected seedling survivorship of both species. Low survivorship in seedlings of the canopy species may doom the present-day warm-temperate evergreen forest of Persea thunbergii on the island. Mechanical impacts of trampling and burrowing and the resulting soil erosion may play an important role in forest regeneration and dynamics.

The vegetation of breeding sites of streaked shearwaters was studied to determine the effect of the birds' burrow-nesting on the vegetation of Biro Island in Kochi Prefecture, southwestern Japan. The vegetation changes along an altitudinal gradient on Biro Island, in the order of : wind-exposed grassland (e.g. Carex oahuensis var. robusta-Miscanthus condensatus community), wind-exposed evergreen scrub (e.g. Camellia japonica community, Eurya emarginata community and Ardisia sieboldii community) and evergreen broad-leaved forest (Arisaemato ringentis-Perseetum thunbergii). Burrow-nests were often found under the roots of C. oahuensis var. robusta and M. condensatus on the grassland and near the stems and roots of trees in the forest. There were no significant differences in burrow density among the three areas of vegetation. Compared with insular vegetation dominated by C. oahuensis var. robusta or M. condensatus, mean species per stand tended to be low on Biro Island. The conspicuous growth of C. oahuensis var. robusta and M. condensatus appeared to lead to poverty of plant species on the grassland. This study also suggests that the evergreen broad-leaved forest has provided the streaked shearwater on Biro Island with a stable habitat at present, although the burrow-nesting is causing some modifications in the species composition.

Effects of burrowing by streaked shearwaters (Calonectris leucomelas) on the lucidophyllous forest (association : Arachniodo-Castanopsietum sieboldii) were studied on Ohshima Island in Mie, Japan in 1991. The association was divided into a Damnacanthus indicus variant (differential species : Damnacanthus indicus and Eurya japonica) and a Cocculus orbiculatus variant (differential species : Cocculus orbiculatus, Pueraria lobata and Menispermum dauricum, etc.) which were non-burrowing sites and burrowing sites, respectively. The D. indicus variant was characterized by forest floor species including character species of Camellietea japonicae, while the C. orbiculatus variant was characterized by forest edge species including character species of Rosetea multiflorae. The vegetative differences between the D. indicus variant and the C. orbiculatus variant clearly reflected the ecological characteristics of non-burrowing and burrowing sites. The burrow density of the seabird was low (6.0 + 2.0/100 m^2) on the island. The burrows were found mostly under the roots of trees (62.2%) , and their distribution pattern was aggregated (1_δ=1.67). This may suggest some selection of habitat by streaked shearwaters. The percentage of therophyte (annual plant) was significantly high in the burrowing sites, while the percentages of character species of Camellietea japonicae and canopy cover were significantly low. It is suggested that biotic interactions by streaked shearwaters tended to modify vegetation and destroy forest structure, even though the rookery density was low. The relationship between vegetative structure and habitat of streaked shearwaters, and rookery site selection in the vegetation are discussed.