共查询到20条相似文献,搜索用时 109 毫秒
1.
西双版纳片段化石灰岩森林附生兰科植物多样性研究 总被引:1,自引:0,他引:1
西双版纳石灰岩地区拥有丰富的兰科植物资源,但近年来随着橡胶树的大面积种植,使得该地区很多石灰岩森林呈片段化。为了解片段化石灰岩森林中附生兰科植物多样性状况以及片段化对附生兰科植物的影响,该研究选取了生境片段化的青岩寨和曼纳览,以及连续生境的绿石林和巴卡新寨等4个样地的29个样方进行多样性调查和对比研究。结果表明:4个石灰岩森林样共记录到附生兰科植物34属76种1 528株(丛)。通过对坡向、坡度、海拔、地形、郁闭度和森林类型等6个环境因子与附生兰科植物丰富度进行CCA分析,发现石灰岩地区附生兰科植物的分布主要受海拔和森林类型2个因素的影响,在海拔较高的青岩寨和巴卡新寨附生兰科植物物种丰富度高于低海拔的绿石林和曼纳览,而片段化对附生兰科植物的物种多样性和多度均无显著影响,这可能与片段化的历史较短有关。虽然目前来看生境片段化对石灰岩地区的附生兰科植物多样性无显著影响,但生境脆弱的石灰岩森林植被的保护对于兰科植物多样性保护则更具重要性。 相似文献
2.
海南岛石灰岩特有植物的初步研究 总被引:9,自引:1,他引:8
特有植物是了解一个地区植物区系的起源与演化规律的关键。对海南岛石灰岩特有植物的地理分布特征和分类的初步研究表明:本区共有石灰岩特有植物63种,隶属于37科52属,其中热带性的属占的比例较高;属于海南石灰岩专性种的有18种,一些种类对生长基质的要求相当严格。与其它地区比较,石灰岩山地的特有化发展在海南不很明显。从特有植物的分布来看昌江是海南一个重要的石灰岩植物分化中心。对海南石灰岩特有种比例较低的原因和保育进行了探讨。 相似文献
3.
4.
广东石门台自然保护区石灰岩地区植物区系和植被 总被引:8,自引:1,他引:7
分析了广东英德石门台自然保护区石灰岩地区森林植被的植物种类组成。外貌结构,群落类型和分布状况及石灰岩植物的主要适应特点,并对如何保护和恢复石类岩地区的森林植被提出了建议。 相似文献
5.
蒸腾作用是植物水分关系中的一个重要部分,它基本上是蒸发的物理过程,因此受环境因子的影响,同时它也是受植物体本身结构特点影响的生理过程。对植物的蒸腾强度测定,有利于了解植物与环境之间的关系。千里香[Murraya paniculata(L.)Jack]是一种主要生长于石灰岩地区的具有重要药理作用的植物。其生长地的土壤浅薄,而基岩本身又易透水,故石灰岩地区蓄水保水能力较差,土壤常较干燥,测定千里香植物的蒸腾强度,有利于了解石灰岩地区植物的某些特点。 相似文献
6.
<正> 广西生长的大戟科植物,国内、外学者曾予研究;作者编写中国植物志过程,查阅广西植物研究所植物标本室(IGB)和广西中医药研究所植物标本室(GXMI)收藏的近年在广西石灰岩地区采集的一批标本,其中一些种类,对广西植物区系的探讨,具有一定意义。现报道广西石灰岩山地生长的3个我国新纪录种。 相似文献
7.
通过对既是典型的酸沉降污染区又是典型石灰岩地区的柳州进行的2次野外植物伤害考察发现,在被调查的436种植物中,84种受到酸沉降污染轻度伤害,30种受到重度伤害。经分析表明,石灰岩植物比非石灰岩植物对酸沉降敏感;落叶植物比常绿植物对酸沉降敏感。市区内近地大气中SO2含量高于远郊区是市区内行道树严重受害的主要原因之一。 相似文献
8.
中国南部的石灰岩纯岩出露面积约198000km2,位居世界各国同类面积之首,主要分布在广西,贵州,云南东部,广东北部,湖南和湖北的西部,以及四川南部,尖削的石峰和美丽的岩洞是游人的胜地,也为生物和人类提供了多种多样的生态位。石灰岩地区已记录到4000多种维管植物和丰富的动物区系,被世界自然和自然资源保护组织(IUCN)列为国际植物多样性中心之一,区内居住人口约四千万,包括我国半数以上的少数民族,和少数民族中人口最众的壮族。保护石灰岩地区森林已经迫在眉睫。我国人口在近四十年内增长了一倍多,东部人口密度达到每平方公里249人。人口压力和对自然资源过度的开发已经毁灭了80%以上的原生性石灰岩森林,令大多数石山成为全裸或半裸的光头山。森林消失后,很多生物种失去藏身之处,濒临灭绝;受威胁石灰岩植物已记录到近三百种。石灰岩森林涵养水源,是区内人民生活的一项基本保障。森林被毁后,石灰岩地区即面临缺水问题;没有森林覆盖,土壤流失严重,生产条件恶劣,人民生活普遍贫困。例如广东地区年均国民收入超过二仟美元,接近或达到了小康水平,但粤北石灰岩地区不足壹佰美元,温饱仍然未解决。传统的生物保护方法,以设立自然保护区为主,虽然为一些生? 相似文献
9.
10.
中国兜兰属植物生态地理分布 总被引:15,自引:0,他引:15
分析了国产兜兰属植物的生态地理分布特点和发展趋势及兜兰属植物的系统演化趋势与生态地理环境的关系。国产兜兰野生种共有 18种 ,主要分布于热带过渡地区 (南亚热带 ) ,主产西南各省区 ;大多数种类生长于石灰岩山地 ,多为半附生兰 ,呈丛生生长 ,另一部分生长于酸性砂岩面的腐叶土上 ,多为地生兰 ,呈单株生长或分蘖状散生 ;大部分兜兰分布于较高海拔地区 ;国产兜兰属中最原始的短瓣亚属绝大部分种类仅分布在滇东南地区与贵州、广西连成一片的岩溶地貌的石灰岩地区 ,而兜兰属中较进化的兜兰亚属大部分种类在本区皆有分布。以上说明滇东南的石灰岩地区可能是兜兰属的起源中心和演化中心 ,中国的南亚热带地区是兜兰属植物的生态多样性中心 相似文献
11.
12.
13.
14.
15.
石山稀有濒危植物在迁地保护后的性状变异 总被引:8,自引:0,他引:8
本文对比研究了7种石山稀有濒危植物在石灰岩土壤以及迁移到酸性土壤后的外形特征,生长发育习性及化学元素含量,结果表明,7种石山稀有濒危植物迁移到酸性土壤后发生了以下变化:1)外形变化主要表现为叶片变大变薄,有的植物种子或叶形有变化;2)迁移后开花,结实,落叶期晚1周以上,在气候条件相同的地区,营养生长期没有变化;3)植物体内的化学元素N,Zn,B,Al的含量增加20%以上,而Ca含量减少10%;4)Al的含量虽增加很多,但仍远低于酸性土壤中的植物;Ca的含量虽然减少,但仍高于酸性土壤植物;5)元素K,B的生物吸收系数在石灰岩土壤高于酸性土壤,其他元素N,P,Ca,Mg,Fe,Al,Mn,Zn的生物吸收系数则是酸性土壤高于石灰岩土壤。 相似文献
16.
《Journal of bryology》2013,35(4):253-257
AbstractThe liverwort Athalamia hyalina (Sommerf.) S.Hatt. and the family Cleveaceae are reported as new to the British Isles from the eastern Scottish Highlands. The Scottish plants are described and illustrated and the significance of the discovery is assessed. In Scotland, Athalamia hyalina occurs on thin soil on eroding limestone ledges in a montane habitat with a continental climate. It is in active growth in the winter months, producing spores in spring. Its range is restricted but it occurs within a protected area and is not threatened at present. The species is widespread in the northern hemisphere. 相似文献
17.
Tropical dry forests are the most threatened forest type in the world yet a paucity of research about them stymies development of appropriate conservation actions. The Paranã River Basin has the most significant dry forest formations in the Cerrado biome of central Brazil and is threatened by intense land conversion to pastures and agriculture. We examined changes in Paranã River Basin deforestation rates and fragmentation across three time intervals that covered 31 yr using Landsat imagery. Our results indicated a 66.3 percent decrease in forest extent between 1977 and 2008, with an annual rate of forest cover change of 3.5 percent. Landscape metrics further indicated severe forest loss and fragmentation, resulting in an increase in the number of fragments and reduction in patch sizes. Forest fragments in flatlands have virtually disappeared and the only significant forest remnants are mostly found over limestone outcrops in the eastern part of the basin. If current patterns persist, we project that these forests will likely disappear within 25 yr. These patterns may be reversed with creation of protected areas and involvement of local people to preserve small fragments that can be managed for restoration. 相似文献
18.
The pine rocklands of southern Florida are a fire-dependent forest associated with outcroppings of limestone. Pine rockland
plants have several adaptations to fire, and for many species burns increase plant growth, flowering, and seedling establishment.
The pine rockland forest has been reduced and fragmented in recent decades. Outside of Everglades National Park, only two
percent of the original pine rocklands remain, and are in the form of small fragments. Habitat fragmentation may have a negative
effect on the biology of plants; we investigated the effects of both fire and fragmentation on Angadenia berteroi (A.DC.) Miers, a threatened species of the southern Florida pine rockland. We estimated the density and flowering of A. berteroi using adaptive cluster sampling in six study sites with different fire and disturbance histories. A. berteroi is more abundant in the largest fragments, and those having experienced fire most recently. However, fragmentation and lack
of fire did not appear to have a great impact on flowering or fruit production. Insights from this threatened species may
provide impetus not only to conserve, but to properly manage remaining pine rocklands in south Florida. 相似文献
19.
Alice Latinne Surachit Waengsothorn Vincent Herbreteau Johan R. Michaux 《Conservation Genetics》2011,12(6):1495-1511
Leopoldamys neilli is a threatened murine rodent species endemic to limestone karsts of Thailand. We have studied the phylogeography of L. neilli using two mitochondrial markers (cytb, COI) and one nuclear fragment (bfibr), in order to assess the influence of its endemicity
to karst habitat. One hundred fifteen individuals of L. neilli were collected in 20 localities throughout the geographic range of this species in Thailand. Our study revealed strong geographic
structure of the mtDNA genetic diversity: six highly differentiated, allopatric genetic lineages were observed in our dataset.
They exhibit a very high degree of genetic divergence, low gene flow among lineages and low levels of haplotype and nucleotide
diversities within lineages. Our results suggest that L. neilli’s populations are highly fragmented due to the scattered distribution of its karst habitat. The most divergent lineage includes
the populations from western Thailand, which have been separated from the other genetic lineages since at least the Early
Pleistocene. The other lineages are more closely related and have diverged since the Middle Pleistocene. This study revealed
an unexpected high level of genetic differentiation within L. neilli and highlighted the high endemicity of this species to limestone karsts. Our results enhance the importance of protecting
limestone habitats to preserve not only the species but also intraspecific diversity. 相似文献
20.
Alvar grasslands are thin-soil calcareous grasslands on Silurian and Ordovician limestone bedrock. They are considered unique
plant communities for northern Europe and America with a high conservation value. Until now, European alvar grasslands have
only been described in Sweden and Estonia. We described species-rich alvar grasslands on the Izhora plateau, NW Russia and
compared this vegetation with that of Estonian alvar grasslands. Floristic composition and environmental conditions of Russian
alvars were similar to Estonian alvar grasslands on thicker dry soil. Russian alvars are isolated from similar communities
in Estonia, but extensive transport of domestic animals from Estonia to NW Russia in past centuries has probably enhanced
species dispersal. Some characteristic Estonian alvar species were missing in NW Russia because it lies outside their natural
ranges. Other differences in vegetation were explained by higher atmospheric nitrogen deposition and younger age of Russian
sites. In NW Russia the alvar grasslands were small, but several red-listed plant species were present. In order to preserve
European alvar vegetation effectively, Russian alvar grasslands need further study and conservation as an outpost of this
threatened vegetation type. 相似文献