首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
为了解八大公山国家级自然保护区内的蝴蝶群落组成及海拔分布, 作者于2016-2018年间对该区域不同生境的蝴蝶群落进行了系统调查和多样性分析, 并持续观测其群落的月动态变化。本研究共记录蝴蝶6,164只, 隶属于5科107属191种。低海拔(250-450 m)生境记录到的蝴蝶以凤蝶亚科为主, 高海拔(1,200-1,400 m)生境以粉蝶亚科为主, 而中海拔(700-900 m)生境无明显的蝴蝶优势类群。相似性分析结果表明, 各生境存在很高比例的共有种(59%以上), 这些共有种在不同生境的个体数分布存在很大的差异。季节动态分析结果表明, 八大公山蝴蝶群落的物种数、个体数及多样性指数在4-6月逐渐上升, 7月达到峰值, 8-9月逐渐下降。总体来说, 八大公山的蝴蝶群落组成沿海拔梯度呈现垂直分布差异, 高海拔与低海拔存在明显的异质性, 中海拔则呈现出一种过渡状态; 且八大公山不同海拔的蝴蝶群落表现出较为一致的季节动态, 都具有很高比例的物种更替; 相对于低海拔, 高海拔生境蝴蝶群落的活跃期更短, 物种的时间周转率更高。  相似文献   

2.
Ants were extracted in Winkler bags from sifted leaf litter sampled in arange of forest and woodland types in and around Mkomazi Game Reserve innorth-eastern Tanzania, including the Eastern Arc Mountains of South Pare andWest Usambara. A total of 87 ant species were recorded, of which 32.2% were onlyrecorded from montane forests (1400–1850 m altitude), 6.9%only from lowland forest (540–810 m), 19.5% only fromwoodland (300–1080 m), and 16.1% in all three forest types.Of the 28 species recorded only from montane forests, 12 species were only foundin the Mkomazi forests, four only in the Pares and seven species only in theUsambaras. Sites of similar altitude grouped together in a cluster analysis, andspecies richness decreased with an increase in altitude. The lowland forest andclosed woodland sites did not form distinct communities. To ensure preservationof ant species, forests from a full range of altitudes need to be conserved.This study confirms the status of the West Usambara forests as having a highlyendemic biota, and the critical need to adequately conserve the remainingvestiges of montane forest within Mkomazi Game Reserve.  相似文献   

3.
分析了金沙江畔7个不同海拔区域花椒园中昆虫群落特征的动态变化及其与温、湿度变化的关系。结果表明:花椒园中昆虫群落的多样性、均匀度、丰富度、Ss/Si、Sn/Sp指标随海拔升高先增加后减少,而个体数、优势集中性指数则随海拔升高先减少后增加;低海拔(450—750 m)区域花椒园中由于总体温度高、湿度低,较高海拔(1300—1550 m)区域总体温度低、湿度高,均不利昆虫群落多样性、均匀度、丰富度、Ss/Si、Sn/Sp指标的提高和群落的稳定,而中等海拔(750—1300 m)区域的温度、湿度较为适中,昆虫群落的物种数及个体数量均相对较高,昆虫群落多样性、均匀度、丰富度、Ss/Si、Sn/Sp指标也较高,群落较稳定;相反,低海拔、较高海拔区域花椒园中昆虫群落优势集中性指数较高,而中等海拔区域却相对较低。综合分析表明,海拔高度及温湿度对花椒园昆虫群落特征影响较大,而海拔高度及温湿度的测量和分析较为方便。  相似文献   

4.
Aims To describe the biodiversity patterns of plants along an altitudinal gradient on the Qinghai-Tibetan Plateau and to clarify the bias in plant specimen records at high altitude.Methods We conducted a large-scale investigation of vegetation at a wide range of altitudes, focusing on a high-altitudinal range (3?200–5?200 m) at different locations on the Qinghai-Tibetan Plateau. We then compared the altitudinal distribution of plant species obtained from our field investigation with that in plant specimen records from published sources and an online database.Important findings Our data provide evidence that altitude plays a large role in regulating species composition on the Qinghai-Tibetan Plateau. We could not, however, detect a clear relationship between altitude and species richness, although a weak monotonically increasing trend of richness was detected with increasing altitude. According to specimen records, most species have been sampled at a wide range of altitudes, and the average range of 145 species is>2?000 m. Despite this wide range, more than half of the species we observed were at higher altitudes than the specimen records indicate. High-altitude areas have probably been so poorly sampled that only a small fraction of the resident species has been recorded. This study clearly shows the regional bias of specimen records in the Qinghai-Tibetan Plateau.  相似文献   

5.
The leaf life span, leaf habit (evergreenness and deciduousness), and species diversity of trees were simulated by a cost-benefit model of leaf longevity (Kikuzawa 1991), using monthly mean temperature values and their decreasing rate with altitude of 6°C with 1000 m of sites of different latitude and altitude in eastern Asia. Numbers of tree species in tropical regions with different lengths of favorable period for photosynthesis were also simulated. The following results were obtained by the model simulation.
  1. In tropical areas, evergreen forests predominate from lowlands to the altitudinal limit of forests.
  2. However, leaf longevity is shorter in the lowland than that at a higher altitude.
  3. Percentages of deciduousness are high in mid latitude, and the percentages of evergreenness again increase in even higher latitude, resulting in a bimodal distribution in percentages of evergreenness with increasing latitudes.
  4. Altitudinal distribution of percentages of evergreenness and deciduousness in mid latitude duplicates the latitudinal distribution. In low altitudes, percentages of evergreenness are high. But in mid altitudes, percentages of deciduousness become high, in even higher altitudes, however, evergreenness again predominates.
  5. Number of species is highest in the non-seasonal tropical region and decreases towards seasonal tropics and higher altitudes and latitudes.
  相似文献   

6.
In summer 2003 we recorded the presence and abundance of alien plant species at 232 sites (107 railway stations and 125 road sites) along mountain passes in the Swiss Alps. The altitudinal distribution of species was related to the current abundance of the species in Switzerland and time since introduction. A total of 155 alien taxa were recorded. Numbers of species per site declined exponentially with altitude, and only a few species were found in the alpine zone (>2000 m). In contrast, species richness among comparable native taxa appeared to be nearly independent of altitude over the range investigated. Maximum altitude reached by alien species was related positively to both total area occupied in Switzerland and to time since introduction. A comparison of the results with earlier records suggests that many species, particularly those previously restricted to low or intermediate altitudes, have advanced their altitudinal limits over the past few decades. Various hypotheses are presented to explain the declining abundance of alien species with altitude: low-altitude filter effects, low propagule pressure, and genetic swamping of peripheral populations at higher altitudes. However, at present we do not have sufficient evidence to determine the relative importance of these effects. We conclude that invasion into mountain areas such as the Swiss Alps tends to proceed rather slowly, though the process may be accelerated by climatic warming. For this reason, further research to investigate the processes determining how plants invade mountain areas is urgently needed. And more generally, investigations into the distribution of alien species along strong altitudinal gradients may provide valuable insights into the mechanisms driving the spread of alien organisms.  相似文献   

7.
Abstract. 1. A survey was made of the distribution of Lonchopteridae over 2 years at forty sites in northern England. Material was collected by pitfall trapping.
2. Two species, Lonchoptera lutea and L.furcata , were taken in approximately similar numbers. No other species were recorded.
3. Considerable separation of the two species was found, with both species occurring at ten sites, whilst one species only was taken at twenty-five sites. L.furcata occurred coinrnonly on upland mineral sods, shallow peat soils and on lowland bogs whilst L.lutea was numerically most abundant on upland blanket bog.
4. Almost 39% of the L.lutea specimens and 14% of the L.furcata captures were males.
5. The capture of numbers of males of L.furcata is unusual, since the species is regarded as being parthenogenetic and males occur only in a very small part of the species' range. Confirmation of the association between the males and females of L.furcata is given, whilst there is close agreement between the cliaetotaxy of British males and females, and British and continental European females. The suggestion that the males belong to an undescribed species is rejected.
6. The seasonal capture of L.lutea adults is similar at all altitudes. Captures of males of L.furcata show an abrupt seasonal change above and below about 420 m; captures being in mid-summer in the higher altitude zone and between October and December at lower altitudes. The captures of females of L.furcata show the same trend, but this is partially obscured by the longer life-span of the females. It is suggested that this difference represents a change in the lifecycle, possibly from an annual to a biannual one at the higher altitudes.
7. The biology and distribution of the Lonchopteridae at low altitudes requires investigation.  相似文献   

8.
This study compares the results of three studies and assesses the effects of seasonal changes in the environment on populations of small mammals at three altitudes in Malawi (Zomba Plateau [1900 m], Liwonde National Park [550 m] and Lengwe National Park [100 m]). Zomba Plateau had a higher annual rainfall (mean 2244 mm), longer wet season, shorter dry season, cooler temperatures and smaller water deficit than either Liwonde NP or Lengwe NP (which had similar climates). Maximum grass biomass (and fluctuation index) was 814 g/m2 (1.7) on Zomba Plateau, 1066 g/m2 (2.7) at Liwonde, and 854 g/m2 (30.5) at Lengwe. Sixteen species of rodents were recorded, 7–9 at each study area; the species on Zomba Plateau did not occur at the lower altitudes, and the lower altitude species did not occur on Zomba Plateau. Percentage Similarity and Coefficients of Community showed that there was considerable similarity between Liwonde and Lengwe, but no similarity between either of them and Zomba Plateau. Mean population densities of small rodents (range, fluctuation index) were 23/ha (15–35, 2.3) on Zomba Plateau, 12.6 (2.7–19.1, 7.1) at Liwonde, and 14.5 (0.9–30.9, 33.9) at Lengwe. Stability of the environment tends to confer stability in demographic characteristics. Reproduction was mainly confined to the wet season (December to April) at all altitudes. Comparison of the proportion of new individuals each month, and the duration of residence by individuals, suggests that turnover of the population was slowest on Zomba Plateau and fastest at Lengwe. There was no evidence for reduced litter size, reduced opportunity for reproduction, or increased age to maturity at the highest altitude compared with the lower altitudes as has been recorded in temperate environments.  相似文献   

9.
Aim This research investigates changes in orchid species composition and diversity, plant breeding system and floral traits along an elevational gradient spanning 2300 m (200–2500 m). Location The study was conducted on Réunion Island (Mascarene Islands, Indian Ocean). Methods Data on the distribution of 135 orchid species from 35 genera were gathered from 121 localities situated between 200 and 2500 m a.s.l. For each locality, 500‐m transects were walked and each orchid species was recorded. Measures of species diversity (species richness, a modified Shannon diversity index and the modified Shannon equitability index) were related to altitude using ordinary least‐squares regression. Species turnover and elevational gradients in species composition were determined by: (1) relating scores of detrended correspondence analysis to altitude using ordinary least‐squares regression, and (2) relating Sørensen similarity indices to differences in altitude using Mantel tests. Finally, the average proportion of species displaying similar floral traits or showing the same breeding system were compared among altitudinal zones. Results Species richness per transect ranged from 1 to 36 species (mean 14.3) and decreased significantly with increasing altitude. Similarly, species evenness decreased significantly with increasing altitude. Around 50% of all orchid species were rare (occurred in fewer than 5% of all localities), and only a few occurred in more than 50% of all localities. Orchid species composition changed continuously with altitude, indicating turnover of species with increasing altitude. Analogously, orchid breeding systems and floral traits also changed with altitude. Relatively more auto‐pollinating species were found at high altitudes compared with mid‐ and low‐altitude sites where animal‐pollinated species were most abundant. Species characterized by a cleistogamous pollination system were found almost exclusively in high‐altitude sites, whereas the proportion of species displaying floral traits related to pollination by long‐tongued moths (sphinx) and flies sharply decreased with increasing altitude. Main conclusions Environmental conditions associated with altitude exert a large influence on orchid species composition and the distribution of orchid breeding systems. Our results revealed a high proportion of auto‐pollinating species, and confirm earlier findings that auto‐pollinating species are more frequent in high‐altitude sites.  相似文献   

10.
We conducted this study to determine the diversity patterns, community structures, and seasonality of ground beetle assemblages along an altitudinal gradient (437–1420 m) on Mt. Sobaeksan, Korea. Ground beetles were collected by pitfall traps installed along an altitudinal gradient (437, 757, 1100, and 1420 m). A total of 32 species belonging to seven subfamilies were identified from 3259 collected ground beetles. The diversity pattern of the ground beetle assemblage according to altitude was neither monotonic decreased nor hump-shaped. However, subfamily assemblages and wing form diversity patterns differed according to altitude and may be correlated with altitude or some other environmental variables. The dominant species were Synuchus cycloderus (29.4%) and Eucarabus sternbergi sobaeksanensis (15.4%) and their seasonal activities according to altitude were similar. According to non-metric multidimensional scaling, ground beetles and altitudes could be divided into two distinct groups: a low altitude group (437–757 m) and a high altitude group (1100–1420 m). Some species were particularly abundant at high altitudes, such as Aulonocarabus koreanus kwonileeique and Poecilus nitidicollis, while others were highly abundant at low altitudes, such as Pterostichus audax, Pterostichus ishikawai, and Synuchus species.  相似文献   

11.
西藏高山草原AM真菌生态分布   总被引:3,自引:1,他引:3  
对西藏高原37种草地植物(建群种或常见种)70个带根土样的AM真菌进行了研究.结果表明:1)在所分离到的5属35种AM真菌中,球囊霉属、无梗囊霉属、盾巨孢囊霉属真菌分别为18、9、6种,内养囊霉属、类球囊霉属各1种.其中,藏南、藏北草原AM真菌分别为4属23种、4属22种,Shannon指数分别为2.31和2.75,但藏北草原AM真菌孢子密度、种的丰度显著高于藏南.2)不同生态区域AM真菌呈共有种较少、特有种较多、优势种差异较大的分布特征.3)高寒草原、山地草甸、高寒草甸草原AM真菌Shannon指数分别为1.91、1.83、1.80,呈严重退化态势的温性草原仅为1.64;海拔4000~4600 m地带,种的丰度最高,海拔4600~5220 m 地带,真菌Shannon指数和物种均匀度最高,分别为2.42和0.79;4)球-囊霉属真菌在不同海拔段均为优势属,但在海拔<4000 m地带相对多度较高;无梗囊霉属主要分布于海拔>4000 m地带;盾巨孢囊霉属主要分布于海拔3500~5220 m地带;类球囊霉属主要见于海拔4000~5220 m的藏北高寒草甸草原,少量见于高寒草原环境;内养囊霉属仅见于海拔3500~3700 m的藏南温性草原.  相似文献   

12.
海拔是地衣多样性的重要影响因素。了解地衣的海拔分布格局是地衣多样性保护的基础。研究表明中国地卷属地衣的物种丰富度和个体丰富度沿海拔梯度呈单峰曲线,它们倾向于分布在受全球变暖影响较高的高海拔地区[(2,022±995)m],且具有较窄的海拔分布幅(约68%的物种分布于海拔为1,694-2,954m的地带),因而对其进行保护生物学的研究已十分迫切。地卷属11种地衣具有不同的海拔分布规律,这些分布规律与各自分布的海拔区间有关。基于11物种的海拔分析支持Rapoport法则。全球暖化对4种地衣的潜在威胁尤其强烈,即:大陆地卷Peltigera continentalis、长孢地卷P. dolichospora、克氏地卷P. kristinssonii和小地卷P. venosa。  相似文献   

13.
Abiotic and biotic factors that change with altitude can influence the distribution of herbivorous insects. We examined factors influencing the distribution of the generalist leafminers Liriomyza sativae Blanchard and Liriomyza huidobrensis Blanchard (Diptera: Agromyzidae), two pests of agricultural crops, in the tropical Dieng mountainous area of Central Java, Indonesia. Liriomyza huidobrensis predominated at altitudes above 700 m a.s.l. and was the only species collected above 1 400 m a.s.l. In contrast, L. sativae predominated below 600 m a.s.l. and was not found above 1 200 m where the average temperature was 20.7 °C. Parasitoid diversity decreased with altitude, but parasitism did not change. The distribution of neither species was affected by parasitoids; L. huidobrensis predominant at high altitudes was preferred by Opius parasitoids common at these altitudes. Intra‐ and interspecific competition was detected in laboratory experiments where larval density was high, but led to coexistence rather than species displacement. No competition was detected in a field experiment when larval density was low. However, L. sativae failed to reproduce at the highest altitude, whereas L. huidobrensis established at all altitudes. Host composition varied with altitude and one host (faba beans) preferred by L. huidobrensis was common at high altitudes. By relating published data on the performance of the leafminer species to altitudinal temperature changes, we were partly successful in predicting the altitude at which the dominant species switched. Temperature plays an overriding influence on the altitudinal distribution of leafminers.  相似文献   

14.
Growing vulture populations represent increasing hazards to civil and military aircraft. To assess vulture flight behavior and activity patterns at the Marine Corps Air Station in Beaufort, South Carolina, we equipped 11 black vultures (Coragyps atratus) and 11 turkey vultures (Cathartes aura) with solar-powered Global Positioning System (GPS) satellite transmitters during a 2-year study (1 Oct 2006–30 Sep 2008). Turkey vultures had larger seasonal home ranges than did black vultures, and 2 turkey vultures made round-trips to Florida. Black vultures consistently spent less time in flight (8.4%) than did turkey vultures (18.9%), and black vultures flew at higher altitudes than did turkey vultures in all seasons except summer when altitudinal distributions (above ground level) did not differ. Although we recorded maximum altitudes of 1,578 m for black vultures and 1,378 for turkey vultures, most flights were low altitude. A matrix of vulture flight altitude versus time of day revealed that >60% of vulture flight activity occurred from 4 hr to 9 hr after sunrise at altitudes below 200 m. Continuation of aggressive harassment coupled with flexible training schedules to avoid times and altitudes of high vulture activity will decrease hazards to aircraft posed by these birds. © 2011 The Wildlife Society.  相似文献   

15.
We studied the distribution of Palearctic green toads (Bufo viridis subgroup), an anuran species group with three ploidy levels, inhabiting the Central Asian Amudarya River drainage. Various approaches (one‐way, multivariate, components variance analyses and maximum entropy modelling) were used to estimate the effect of altitude, precipitation, temperature and land vegetation covers on the distribution of toads. It is usually assumed that polyploid species occur in regions with harsher climatic conditions (higher latitudes, elevations, etc.), but for the green toads complex, we revealed a more intricate situation. The diploid species (Bufo shaartusiensis and Bufo turanensis) inhabit the arid lowlands (from 44 to 789 m a.s.l.), while tetraploid Bufo pewzowi were recorded in mountainous regions (340–3492 m a.s.l.) with usually lower temperatures and higher precipitation rates than in the region inhabited by diploid species. The triploid species Bufo baturae was found in the Pamirs (Tajikistan) at the highest altitudes (2503–3859 m a.s.l.) under the harshest climatic conditions.  相似文献   

16.
Species richness patterns along altitudinal gradients are well-documented ecological phenomena, yet very little data are available on how environmental filtering processes influence the composition and traits of butterfly assemblages at high altitudes. We have studied the diversity patterns of butterfly species at 34 sites along an altitudinal gradient ranging from 600 to 2,000 m a.s.l. in the National Park Berchtesgaden (Germany) and analysed traits of butterfly assemblages associated with dispersal capacity, reproductive strategies and developmental time from lowlands to highlands, including phylogenetic analyses. We found a linear decline in butterfly species richness along the altitudinal gradient, but the phylogenetic relatedness of the butterfly assemblages did not increase with altitude. Compared to butterfly assemblages at lower altitudes, those at higher altitudes were composed of species with larger wings (on average 9 %) which laid an average of 68 % more eggs. In contrast, egg maturation time in butterfly assemblages decreased by about 22 % along the altitudinal gradient. Further, butterfly assemblages at higher altitudes were increasingly dominated by less widespread species. Based on our abundance data, but not on data in the literature, population density increased with altitude, suggesting a reversed density–distribution relationship, with higher population densities of habitat specialists in harsh environments. In conclusion, our data provide evidence for significant shifts in the composition of butterfly assemblages and for the dominance of different traits along the altitudinal gradient. In our study, these changes were mainly driven by environmental factors, whereas phylogenetic filtering played a minor role along the studied altitudinal range.  相似文献   

17.
Questions: Do growth forms and vascular plant richness follow similar patterns along an altitudinal gradient? What are the driving mechanisms that structure richness patterns at the landscape scale? Location: Southwest Ethiopian highlands. Methods: Floristic and environmental data were collected from 74 plots, each covering 400 m2. The plots were distributed along altitudinal gradients. Boosted regression trees were used to derive the patterns of richness distribution along altitudinal gradients. Results: Total vascular plant richness did not show any strong response to altitude. Contrasting patterns of richness were observed for several growth forms. Woody, graminoid and climber species richness showed a unimodal structure. However, each of these morphological groups had a peak of richness at different altitudes: graminoid species attained maximum importance at a lower elevations, followed by climbers and finally woody species at higher elevations. Fern species richness increased monotonically towards higher altitudes, but herbaceous richness had a dented structure at mid‐altitudes. Soil sand fraction, silt, slope and organic matter were found to contribute a considerable amount of the predicted variance of richness for total vascular plants and growth forms. Main Conclusions: Hump‐shaped species richness patterns were observed for several growth forms. A mid‐altitudinal richness peak was the result of a combination of climate‐related water–energy dynamics, species–area relationships and local environmental factors, which have direct effects on plant physiological performance. However, altitude represents the composite gradient of several environmental variables that were interrelated. Thus, considering multiple gradients would provide a better picture of richness and the potential mechanisms responsible for the distribution of biodiversity in high‐mountain regions of the tropics.  相似文献   

18.
A survey of 93 wetlands in six catchments across the Maloti-Drakensberg is used to assess the distribution of plant functional types across altitudinal and wetness gradients. Altitudes range from 1,000 to 3,200 m a.s.l. Within each catchment, the wetlands were selected to cover the complete range in altitude and wetland types. In each of the selected wetlands, vegetation was sampled in 3 by 3 m quadrats covering the entire range of wetness represented in the wetland, from temporarily wet to permanently inundated soils. Plant species were allocated to one of 11 different functional types (examples are C3 grasses, C4 sedges, rosette plants, and shrubs), and the proportion of the vegetation in each sample occupied by each functional type was calculated from the species’ abundances. Canonical Correspondence Analysis shows that “wetness” clearly has the highest impact on the distribution of functional types, followed by altitude. The most important plant functional types in wetlands are grasses and sedges, however, at higher altitudes, forbs (especially rosette plants) and bulbous plants become a more prominent feature in the wetlands. The total amount of graminoids gradually decreases with altitude. The general trend is that sedges tend to increase with increasing wetness and C3 plants (grasses and sedges) increase with increasing altitude, but these effects are not independent. The distributions of C4 sedges and C4 grasses along an altitudinal gradient are quite different, and C4 grasses grow abundantly at much higher altitudes than C4 sedges. C4 sedges are very scarce at the altitudes represented in the Maloti-Drakensberg area, whereas C3 grasses occur in the permanently wet parts of the wetlands, especially at higher altitudes (normally mostly occupied by sedges). Shrubs are rare in wetlands and tend to be an indication of disturbance. This study complements previous studies on the distribution of grasses and sedges at the lower altitudes within KwaZulu-Natal, which found that at altitudes below 1,000 m a.s.l. C4 sedges were much more prominent, while forbs and rosette plants were largely absent. This confirms that C4 as an adaptation to hotter and warmer climates is sometimes a less favorable metabolism in wet high altitude areas. At high altitudes, rosette plants and bulbous plants become more competitive in wetlands, probably because grasses and sedges present at these altitudes generally grow smaller than they do in low altitude wetlands.  相似文献   

19.
In two successive years we recorded a total of 3,636 individuals and 17 species of adult lady beetles (Coleoptera, Coccinellidae) in the spruce forests of Pol’ana Mts (the West Carpathians) at altitudes ranging from 600 m to 1,300 m a.s.l. Four lady beetle species were documented as predominating (dominance of abundance > 5%) over the study period. They were the following: Aphidecta obliterata (1,828 individuals and 50.3%), Coccinella septempunctata (634 individuals and 17.4%), Adalia conglomerata (594 individuals and 16.3%) and Anatis ocellata (279 individuals and 7.7%). The assemblages of lady beetles differed among the areas and also between the years. The season revealed neglegible effect on distribution of lady beetles, whereas the effect of altitude was more pronounced. A. conglomerata preferred the areas at lower altitude (600–725 m) to those at middle (900–925 m) and/or upper altitude (1,250–1,300 m). In contrast, A. obliterata and C. septempuctata were most abundant in the area at middle altitude. The altitudinal location of area partly explained the variability in abundance of lady beetles. The first ordination axis constructed by means of correspondence analysis (CA) represented an altitudinal gradient and accounted for 19.4% of the total variance of the species data. The great proportion of lady beetle species not typically associated with spruce and/or other coniferous trees than spruce (70.6%, n = 17) may be explained by an ecotonal effect.  相似文献   

20.
The aim of this study is to analyse the vascular flora and the local climate along an altitudinal gradient in the Lefka Ori massif Crete and to evaluate the potential effects of climate change on the plant diversity of the sub-alpine and alpine zones. It provides a quantitative/qualitative analysis of vegetation-environment relationships for four summits along an altitude gradient on the Lefka Ori massif Crete (1664–2339 m). The GLORIA multi-summit approach was used to provide vegetation and floristic data together with temperature records for every summit. Species richness and species turnover was calculated together with floristic similarity between the summits. 70 species were recorded, 20 of which were endemic, belonging to 23 different families. Cretan endemics dominate at these high altitudes. Species richness and turnover decreased with altitude. The two highest summits showed greater floristic similarity. Only 20% of the total flora recorded reaches the highest summit while 10% is common among summits. Overall there was a 4.96°C decrease in temperature along the 675 m gradient. Given a scenario of temperature increase the ecotone between the sub-alpine and alpine zone would be likely to have the greatest species turnover. Southern exposures are likely to be invaded first by thermophilous species while northern exposures are likely to be more resistant to changes. Species distribution shifts will also depend on habitat availability. Many, already threatened, local endemic species will be affected first.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号