Species turnover and diversity patterns along an evergeen broad-leaved forest coenocline.

Direct gradient analysis was applied to the evergreen broad-leaved forest coenocline in the Tatera Forest Reserve,Japan.10 quadrats of 0.1-0.05 ha were laid out from 140 m to 560 m above sea level at intervals of 25-70 m.Gradient analysis revealed that distributions of many species terminated or started at ca.400 m.Community similarity,calculated in Percentage Similarity (PS) and Community Coefficient (CC),changed abruptly below and above the 400 m contour,suggesting a change of vegetation structure at thisaltitude,which was also clear from population distributions. The spatial turnover rate of species along the altitudinal gradient was calculated in two ways:as the Average turnover rate along the whole range of the gradient, and as the Zone turnover rate at individual altitudes.The overall rates calculated for five categories of populations:DBH>10 cm, DBH>3 cm, all woody species, herb-layer,and total vegetation,were-0.0011 to -0.0021 for PS,and -0.0009 to -0.0019 for CC.The calculated rates(PS basis) indicate that a 95% change in species composition is reached at 1120 to 620 m altitude.Similarly,the rates -0.0009 to -O.0019(CC) correspond to 1410 -680 m.The altitudinal range expected here for a 95% change agrees with the actual elevation of forest zonation in northwestern Kyushu.The average rate of both PS and CC in the herb-layer population was 1.56 times higher than the rate in the woody species population,showing a more rapid change in herb-layer population than in the woody ones along the gradient. The Zone turnover rates were higher at the 370-440 m belt than those below and above the belt.This coincided with the interchanging pattern in population distributions and the abrupt change in similarity at about 400 m above sea level.This may be due to the change in environmental conditions such as physiography and air humidity.In the diversity measurements,the species density per 100 m^2 showed a gradual increase in the DBH>3 cm population but a constant level in the DBH>10 cm population along the whole range of the forest coenocline studied,while index values of S_(100)and Shannon\u27s H\u27 showed decreasing trends in the same gradient with a few exceptionally high and low values

ガラパゴス諸島における植生研究

My stay in the Galapagos Islands was from February to June, 1970. The purpose was to continue field works of vegetation studies from the standpoints of plant ecology and phytosociology, which started in the 1964 Galapagos International Scientific Project. My concerns in the fields are centered on (1) the vegetation-habitat relationships, (2) the floristic composition and structure of plant communities, (3) the distribution of endemic species in relation to habitats and communities, (4) socondary communities replacing natural ones under human impacts such as cutting, trampling, grazing, etc. and (5) mappin& of the natural and secondary communities (Itow, 1965; 1966). The present paper deals with part of the studies made on Isla Santa Cruz concerning (1), (4) and (5)

ガラパゴス諸島固有属スカレシアの分布と生態

Scalesia (Compositae), a genus endemic to the Galipagos Islands,consists of 12 shrubby species distributed in the lowland dry zone and three tree species found in the mid-elevation moist zone. They are completely allopatric in distribution. All the species have herbaceous traits: fast growth, soft wood, large pith at the center of trunk, and flowering within 1 yr after germination (in greenhouse). The tree species Scalesia pedunculata Hook. f. is shade-intolerant and heliophdous, and predominates as a monoculture in themoist zone of the four larger hlgh-elevation islands. In ecological succession, it functions as pioneer, successor, and climax canopy plant. Even at climax or maturity of this monodominant forest, the canopy is not accompanied by young generations beneath owing to its shade-intolerance. The canopy population of postmature forest dies back nearly synchronously. A new generation then develops to build new forest. The progression from germination to maturity, and further to senescence and die back, is a self-cyclic succession, without change of dominant species. Over much of its range, S. pedunculata is endangered by the effects of past agricultural exploitation or heavy browsing by free-ranging goats, pigs, and donkeys; however, the population on the north side of Isla Santa Cruz has been preserved in good condition in the Galipagos National Park

ガラパゴス諸島サンタクルス島における植物の固有性、種の交代および種多様性の標高変化

Vegetation zones of Isla Santa Cruz in the Galapagos Islands range from the lowland dry zone, through transition and moist zones, to the highland zone, reflecting the precipitation pattern. The zones are deflected upward on the leeward north side, as compared with the windward south side. The brown subzone and Miconia robinsoniana scrub of the moist zone are absent on the north side. Zonation and species distribution patterns are also related to altitude and substrate. Floristic and phytosociological endemisms for woody species increase with higher altitude, while those of herbaceous species are low in high elevations because of low endemism in pteridophytes. Species turnover rate along the altitudinal gradient is three times higher on the windward south side than on the leeward north side. Species diversity is low in Scalesia pedunculata forest, where stand-level dieback has occurred as a consequence of the species-poor constitution

Field notes of Galapagos Vegetation Studies in 1970 and 1978

Syuzo ITOW conducted field studies of plants and vegetation from February to June, 1970, and from February to April, 1978, in the Galapagos Islands, Ecuador. When in the field, he recorded individual plants and other aspects of vegetation, as well as topography and habitat conditions, using Japanese and Chinese characters, and collected voucher specimens that could be properly identified at a later date. The present notes consist of the translation from original Japanese descriptions into English, and compiled association tables of selected plant communities, with identifications of voucher specimens. The notes are open to public use in any form

ガラパゴス諸島、サンタクルス島高地における草本とツツジ科群落

The herbaceous and ericaceous vegetation in the highlands of Santa Cruz was studied to find relations of plant communities to topographical relief. The vegetation was classified into six conlnlunities according to a scatter diagram of vegetation samples (releves) processed by the reciprocal averaging method and according to the dominant species. The communities classified are Paspalum conjugatum community, Pteridium aquilinum/ Blechnum polypodioides community, Lycopodium clavatum community, Hypericum uliginosum community, Polypodium tridens community, and Pernettya howellii community. Of the communities recognized, the Paspalum conjugatum community was found on moist, gentle slopes and flat sites. The Pernettya howellii community was established on southeast-facing, steep slopes at higher altitudes exposed directly to the southern trade winds. This habitat becomes wet or moistened by moisture-saturated southern winds on cloudy and foggy days, but dries up in extended dry periods. The Polypodium tridens community was found only on nearly exposed lava. The three other communities were intermediate between the Paspalum community and the Pernettya community in phytosociological and topographical relations.Acknowledgment: this article is digitized with the permission of Missouri Botanical Garden Press

シバーツボクサ群集について

九州北西部・本州西端部の標高300m以下の13地区のシバ草原は, 他地域の群落との比較にもとづいて, シバーツボクサ群集と認められた。その発達領域はシイ林域にあり, 標徴種ツボクサとハイメドハギにより, シバ群団の他の群集より区別される。本群集は, ハマゼリー, 典型一, トダシバー亜群集をふくみ, 前二亜群集は塩風の影響をうける沿岸部に発達する。ハマゼリ亜群集は, ダルマギクーおよび典型一変群集に区分され, 前者は海にもっとも近くかつ放牧家畜の影響が少ない傾斜地にあり, 海岸植物を多くふくむ。典型変群集および典型亜群集は緩傾斜地ないし平坦地に発達し, 家畜による影響が強集, 沿岸部放牧草原の広い面積を占める。トダシバ亜群集は塩風の影響をうけず, 1kmないし5km内陸の丘陵地に発達する。Based on phytosociological and ecological studies of low-elevation grazed grasslands in northwestern Kyushu and on a comparison of them with related communities, the Zoysia japonica community found in the area studied was recognized as a new association of Zoysion japonicae and was named Centello-Zoysietum japonicae. The association is found only in lowland areas of the warm-temperate region. It is characterized and differentiated from the four associations of the alliance described by SUGANUMA (1966) by the presence of two character species, Centella asiatica and Lespedeza cuneata var. serpens, and by the absence of the character species of SUGANUMA\u27s four associations. The Centello-Zoysietum is subdivided into three subassociations : Subass. of Cnidium japonicum, Typical Subass. and Subass. of Arundinella hirta. The first two subassociations are located on coastal areas influenced by salt spray from the sea. The Subass. of Cnidium japonicum is further subdivided into Variant of Aster spathulifolius and Typical Variant. The former variant is restricted to steeper slopes under lighter grazing and trampling by animals, while the Typical Variant and the Typical Subass. occupy gentle slopes and fiat sites which are heavily disturbed. The Subass. of Arundinella hirta is found on hills, 1 km to 5 km from the sea.Without Tables. For Table1 and Table 2, see http://ci.nii.ac.jp/naid/110001881395

ガラパゴス諸島固有属スカレシアの分布と生態

Scalesia (Compositae), a genus endemic to the Galipagos Islands,consists of 12 shrubby species distributed in the lowland dry zone and three tree species found in the mid-elevation moist zone. They are completely allopatric in distribution. All the species have herbaceous traits: fast growth, soft wood, large pith at the center of trunk, and flowering within 1 yr after germination (in greenhouse). The tree species Scalesia pedunculata Hook. f. is shade-intolerant and heliophdous, and predominates as a monoculture in themoist zone of the four larger hlgh-elevation islands. In ecological succession, it functions as pioneer, successor, and climax canopy plant. Even at climax or maturity of this monodominant forest, the canopy is not accompanied by young generations beneath owing to its shade-intolerance. The canopy population of postmature forest dies back nearly synchronously. A new generation then develops to build new forest. The progression from germination to maturity, and further to senescence and die back, is a self-cyclic succession, without change of dominant species. Over much of its range, S. pedunculata is endangered by the effects of past agricultural exploitation or heavy browsing by free-ranging goats, pigs, and donkeys; however, the population on the north side of Isla Santa Cruz has been preserved in good condition in the Galipagos National Park

ガラパゴス諸島の植生における帯状構造、遷移過程、外来種侵入について

The Galapagos Islands, located 1,000 km west of the South American coast on the equator in the easternmost Pacific, are of volcanic origin. The vascular plant flora is poor and disharmonic, comprising ca. 200 endemic taxa. The vegetation is altitudinally arranged, roughly related to the increase in precipitation, from the maritime and dry zones in the lowlands, through the transition and moist zones, to the treeless highland zone. The zonation is deflected upward in elevation on the leeward side of each island and on leeward islands, due to the rainshadow of the southeastery trade winds which bring moisture to the islands. The treelessness of the highlands is attributed to the fluctuation of weather conditions between extreme dryness and extreme moisture saturation, to which no tree species adapted to such fluctuation has migrated and in which no endemic trees have evolved. Of the flora, an endemic genus Scalesia (Compositae) has attracted special attention. The genus consists of 15 heliophilous species, of which 12 are shrubs distributed in the dry lowlands and three are trees found in the moist zone. All the species are allopatric in distribution. Scalesia pedunculata, the largest tree of the genus, 12 m high and 15 cm in DBH, predominates in the moist zone of Santa Cruz Island. The canopy population of the dense forest is a cohort of the same age, and nearly all the trees die synchronously at maximum maturity, triggered by a large amount of El Nino rainfall or by extreme drought in La Nina years. Such a stand-level dieback resets the cohort generation, and then self-cyclic succession starts with no successors or shade-tolerant trees. The same was observed in an S. cordata forest on Sierra Negra Volcano of Isabela Island. Alien plants, introduced intentionally or accidentally to the islands, are spreading into semi-natural and natural areas as well as in disturbed habitats. Aliens have increased since the first half of the 19th century and now exceed 600 in number of species. Naturalized aliens include tree species that establish self-recruiting populations filling gaps in habitats and tree niches, since the flora is poor in tree species. El Nino rainfall creates favorable conditions for invasive aliens and accelerates their expansion to semi-natural and natural vegetation. Some of the endemic taxa are declining to endangered status due to invasion by alien plants and grazing by introduced animals like goats and donkeys. The vegetation is changing not only in agricultural and town areas but also in part of the Galapagos National Park despite its strict regulations for protection and conservation.出版者原稿の一部改訂（p.42, p.43, p.49）Rivised from published version(p.42, p.43, p.49