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991.
人类活动对泰山景观多样性时空变化的影响 总被引:2,自引:0,他引:2
人类活动改变景观格局多样性,同时又是景观异质性的一个主要来源。采用1986年和2001年两期的遥感数据,研究了泰山二十世纪80年代中期以来景观多样性的时空变化特征以及人类活动对该地区景观格局的影响。结果表明,在泰山地区,人类活动的强弱与景观的破碎化表现出一定的相关性,人类作用强的地区景观斑块面积较小,作用弱的地区斑块面积较大。人为活动改变了荒山荒地,生态恶化受到一定的遏止,但是人类活动的经济目的性较强,道路、居民地、旅游景点等人为景观的出现越来越影响着区域内的景观生态格局,表明缺乏有效管理和监测的人为影响将进一步威胁人类对景观的管理成果。 相似文献
992.
黄山地区松树林外生菌根菌资源及生态分布 总被引:2,自引:0,他引:2
1998~2003年,对黄山地区松树林下外生菌根菌资源及生态分布进行了调查,鉴定出外生菌根菌43种,隶属于10科17属.其中马尾松林下有43种、黄山松林下有12种.马尾松幼林下的外生菌根菌种类单一,彩色豆马勃、硬皮马勃类为优势菌种;马尾松成熟林下外生菌根菌种类丰富,其优势种类为红菇科、鹅膏菌科、牛肝菌科和鸡油菌科的一些种类.并分析了树种植被对外生菌根菌分布的影响,菌根真菌的分布与温度、湿度及土壤条件的关系. 相似文献
993.
北京山区落叶阔叶林中核桃楸在生长中期的树干液流研究 总被引:48,自引:8,他引:40
北京山区落叶叶林优势种--核桃楸在生长中期没有水分亏缺的条件下,树干的液流速率在很大程度上为微气候因子所决定,特别是大气相对湿度、温度和太阳辐射强度等。核桃楸树干液流速率的日进程和大气相对湿度、温度的日进程具有很好的生态学同步性。在一天中树干液流速率会出现数次波动,有多个峰值,最高峰一般出现在15:00左右,可达到1600g/h。在夜晚时核桃楸树干液流速率非常低,一般在50g/h以下,但总是存在, 相似文献
994.
995.
996.
长白山红松阔叶林主要树种高度生态位的研究 总被引:31,自引:6,他引:25
森林生态系统内主要乔木的高度生态位反映了不同树种在各个高度资源单位内资源利用的互补情况,同时也是表征森林生态系统演替的趋势及其森林循环过程主要特征之一.生物学特性和生态学特性接近的树种的高度生态位重叠较大,反之则较小.在Gap内,色木槭和扭筋槭的高度生态位重叠最大,而青楷槭和千金榆、花楷槭和水曲柳、青楷槭和裂叶榆的高度生态位重叠较小;在非Gap生态系统内,青楷槭和白牛槭的高度生态位重叠最大,青楷槭和裂叶榆、青楷槭和千金榆、花楷槭和水曲柳的高度生态位重叠较小.红松和阔叶树之间的高度生态位分离较大,利用资源的方式和能力差异较大,它们之间可以在不同空间的资源利用上达到互补,种间竞争较弱,从而能够保持红松和阔叶树之间长期而稳定的共存.但Gap内红松和阔叶树的高度生态位重叠均大于非Gap生态系统,可见Gap的存在加大了红松和阔叶树之间的种间竞争,减小了红松和阔叶树之间的资源互补利用的能力.Gap削弱了个体生态位重叠值较大的树种间的种间竞争,增强了个体生态位重叠值较小的树种间的种间竞争 相似文献
997.
We investigated whether variation in foliar endophyte frequency among mountain birch trees from different maternal families
was due in part to genetic differences among trees. The effect of different environmental conditions on the susceptibility
of these mountain birch families to foliar endophytes was tested. The 3-year study was conducted in two tree gardens (altitudinal
difference 180 m) with ten families of mountain birch. The frequency of the commonest endophytic fungus in mountain birch
leaves, Fusicladium sp., was significantly affected by mountain birch family, with the ranking of families relative to Fusicladium sp. frequency being consistent from environment to environment. Variation in the frequency of Melanconium sp. was difficult to interpret because of significant family × garden × year interaction. Fusicladium sp. and Melanconium sp. endophytes were most frequent in different tree individuals, families and gardens. We conclude that mountain birch trees
show heritable variation in their foliar endophyte frequency, and thus one of the conditions necessary for foliar endophytes
of mountain birch trees to be able to affect the evolution of their host plant is fulfilled. However, the effect of mountain
birch family on the frequency of endophytic fungi varies depending on the endophytic genera in question and partially also
on environmental conditions.
Received: 28 March 1998 / Accepted: 14 October 1998 相似文献
998.
Lang Kai-Yung 《植物分类学报:英文版》1985,23(6):418-428
The Gongga Mountain Region, located on the eastern fringe of QinghaiXizang Plateau and at the north-eastern end of Hengduan Mountains, is one of the
well-known large mountain areas in Sichuan Province. There are forty five high peaks
with the elavation of 6000 m or over in the area, among which the Gongga Mountain
is the highest one, with its summit being at the altitude of 7556 m, whereas the Dadu
River Valley in the eastern part of the area is only 1150 m above sea level; The relative height in the region is thus about 6400 m.
As we know so far the orchids in Gongga Mountain Region comprise 34 genera and
75 species with 1 variety, of which 12 species are epiphytes, 59 species with 1 variety
terrestrials and 4 species saprophytes (Table 1.).
I. The geographical distribution in the Gongga Mountain Region.
The vertical distribution of the orchids in the area.
Eastern flank: There are 39 species with I variety of orchids at 1150-2300
(-2400) m alt. in the subtropical evergreen broadleaf forest zone, of which 12 species,
such as Bulbophyllum andersonii, Dendrobium hancockii, Otochilus porrecta, etc., are
epiphytic (including a semiepiphyte, Pleione bulbocodioides), 25 species with 1 variety,
such as Bletilla formosana, Calanthe davidii, Cypripedium henryi, etc., are terrestrial,
and 2 species are saprophytic (i.e. Gastrodia elata and Neottia listeroides), the upper
limit of the real epiphytic orchids is 1800 m alt. At the altitude 2300(-2400)-3600
(-3800) m, in the coniferous forest zone, found are 23 species, including 20 terrestrial
species with 1 variety, such as Amitostigma gonggashanicum, Calanthe fimbriata, Coeloglossum viride, etc., 2 saprophytic species (Neottia acuminata and Risleya atropurpurea) and one semiepiphytic species. There are only 2 terrestrial species (i.e. Cypripedium tibeticum and Orchis chusua) at 3600(-3800)-4000m alt., in alpine shrub zone,
the upper limit of the terrestrial orchids being 4000 m alt. At 4000-4400 m alt., in
alpine meadow zone no orchids have so far been found.
Western flank: There are 14 species of orchids, such as Habenaria limprichtii,
Hemipilia flabellata, Satyrium ciliatum, etc., at 2300-2800 m alt., in the river valley
shrub zone, and they all belong to the terrestrial orchids. At the altitude of 28003800m, in the coniferous forest zone found are 19 species of orchids, among which 18
species are terrestrial (such as Amitostigma monanthum, Cephalanthera longifolia, Peristylus coeloceras, etc.) and one is saprophytic. There are only 4 species of terrestrial
orchids (i.e. Cypripedium tibeticum, Gymnadenia orchidis, Orchis chusua and O. diantha) at 3800-4800 m alt., in the alpine shrub-meadow zone, the upper limit of vertical
distribution of terrestrial orchids being 4400 m alt. Twelve species here are common
to the eastern flank.
II. The floristic composition of orchids in Gongga Mountain Region.
1. Twenty three species, belonging to 13 genera, are widespread in Whole EastAsian Region.
2. Eight species, belonging to 8 genera, are the elements of the Sino-Japanese
Subregion.
3. Forty one species with 1 variety, belonging to 24 genera, are the elements of
the Sino-Himalayan Subregion, more than five times the elements of the Sino-Japanese
Subregion.
4. The floristic features of the orchids in the area.
(1) The floristic elements are mainly temperate and subtropical ones.
(2) The life form is mostly terrestrial.
(3) The species endemic to China are prolific (35 species with 1 variety, belonging to 18 genera, are endemic to China, and 26 species with 1 variety are distributed
in south-western China and its adjacent region; Amitostigma gonggashanicum is endemic
to the area).
The floristic composition of orchids in the area is characterized by the dominance
of terrestrial species and temperate and subtropical East-Asian elements, though with
a few Indo-African tropical elements (such as genus Satyrium (1 species) ).
In conclusion, it may be considered that the species of orchids are abundant and
floristic elements are comparatively complex in the Gongga Mountain Region. 相似文献
999.
Pollen analysis of five moss patches collected from the forest floor on West Mountain of Kunming (N 24˚57', E 102˚37') provided informations about the quantitative relations between pollen content and coverage of principal plant taxa. Vegetational data with coverage are estimated from each sampling site within the range of 30 m. Trees were calculated in percentage of the total arboreal, herbs and ferns are respectively computed as percentages of the latter two sorts. A preliminary R-value was estimated. According to the difference of R-values, the pollen types could be divided into two groups: 1. R> 1, means overreprsented the type containing Pinus, Alnus, Cyclobalanopsis, Artemisia, and ferns; 2, R <1, means under-represented the type containing Keteleeria and Michelia. But the differences in the values for RPinus, RAlnus etc. in five samples reflected the significant differences in pollen productivity or pollen dispersal efficiency of Pinus, Alnus, etc. Therefore, the ratio of R-value was equal. Five genera have been calculated. The relative R-values for five tree species were: Ra:Rb:Rc:Rd:Re=l:21:5:25:30 (a. Keteteeria; b. Cyclobalanopsis; c. Castanopsis; d. Pinus and e. Alnus). These computations are only a rough estimate because the samples are too few. 相似文献
1000.
岷山山系大熊猫自然保护区2003年生物多样性监测 总被引:7,自引:1,他引:6
岷山山系是全球生物多样性保护的热点地区之一,有着全世界最大的大熊猫种群和面积最大的大熊猫栖息地。到2003年底,在该地区已建立了20个以保护大熊猫为主的自然保护区。从2003年开始,岷山17个大熊猫自然保护区实施了野外大熊猫及其栖息地监测。通过监测,了解了岷山自然保护区野生动物分布状况、人为活动对自然保护区的干扰情况,以及自然保护区周边社区经济情况,为自然保护区管理决策提供了依据。同时,通过监测活动还提高了自然保护区工作人员的业务水平。建议今后将自然保护区监测工作纳入自然保护区日常工作中。 相似文献