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1.
Liang-Jun Da Min-Ming Kang Kun Song Kan-Kan Shang Yong-Chuan Yang Ai-Mei Xia Yu-Feng Qi 《Ecological Research》2009,24(6):1287-1299
Much of the primary vegetation at low altitudes has been greatly altered or destroyed by a long history of human activities.
This is particularly true in eastern China, where low-altitude areas are now dominated by secondary forests or plantations.
Altitudinal vegetation zonation of this region is often based on these secondary forests, resulting in seral vegetation with
an obscure zonal sequence. Here, we deduced the potential climax vegetation according to the regeneration patterns of the
dominant species of the secondary forests at low altitudes (below 1,000 m a.s.l.) on Mt. Tianmu (1,506 m a.s.l., 30°18′30″–30°21′37″N,
119°24′11″–119°27′11″E). Based on the potential climax vegetation combined with the floristic composition and community structure,
three vegetation zones were identified, viz: (1) evergreen broad-leaved forest zone (400–950 m a.s.l.); (2) evergreen and
deciduous broad-leaved mixed forest zone (950–1,100 m a.s.l.); (3) deciduous broad-leaved forest zone (1,100–1,506 m a.s.l.).
The altitudinal vegetation zones identified in this study correspond with the thermal conditions on Mt. Tianmu. The distribution
of vegetation on Mt. Tianmu was limited by lower temperatures in winter, and the altitudinal thermal vegetation zones on this
mountain were more similar to the thermal vegetation of Japan than to that of China. The vertical distributions and roles
of conifers were different between the eastern and the western regions along 30°N latitude in humid East Asia. Cryptomeria fortunei formed the emergent layer, towering above the broad-leaved canopy at middle altitudes as C. japonica on Yakushima, but disappeared at high altitudes with hydrothermal limitation on Mt. Tianmu. 相似文献
2.
Riparian vegetation, an important mediator of land–water interactions, provides habitat for animals and other organisms; however,
riparian vegetation zones have been altered by agricultural and urban development in Korea. This riparian vegetation survey
was conducted to obtain information vital for the ecological restoration and management of the Korean Geum River ecosystem.
At 100 study sites, along the Geum River, we recorded the vegetation of the Geum riparian zone. We then surveyed the riparian
vegetation associations in the area and overlaid those areas corresponding to trees, shrubs, perennial herbs, annual herbs,
exotic plants, cultivated lands, and damaged lands on a geographical map. We also reconstructed the cross-sectional landscape.
The mean values of vegetation diversity, exotic plant area (%), annual plant area (%), and species richness were 6.47 ± 0.26,
5.44 ± 1.01, 11.98 ± 1.20, and 22.69 ± 0.93, respectively. The landscape elements of the herbaceous plants were more spread
out, compared with those of the woody plants, and 23 sites were composed strictly of herbs. Our results indicate significant
differences in vegetation structure among the study sites. For example, at some sites, exotic plants, cultivated lands, and
damaged lands dominated the landscape comprising 25.7, 62, and 68.9%, respectively, of the area. The riparian landscape reference
model suggested by these results may be applied to studies of other well-conserved riparian zones. We propose that the material
pathways and transport of organisms from land to water at Geum River depend on the patchy distribution of these diverse landscape
elements. 相似文献
3.
The authors examined relationships between Kira's warmth index (WI) and four other important thermal indices: the sums of
daily mean temperatures above 5°C and 10°C, Thornthwaite's potential evapotranspiration (PE) and Holdridge's annual biotemperature.
The thermal records of 671 meteorological stations evenly located all over China were used to make these comparisons. Close
correlations were found within the four relationships, and accordingly WI was used to analyse the thermal distributions of
the main vegetation types. Vegetation types around the 671 stations were read from a vegetation map with a scale of 1/4000000.
Vegetation types at 269 stations corresponded to the natural or seminatural vegetation, and 29 vegetation types were distinguished
by arranging the 269 data into the same or similar types. The geographical distribution of these 29 types and the corresponding
main climatic features were described. The relations between WI and distribution of these vegetation types were discussed
in detail. As a result, WI values (°C month) corresponding to the vegetation zones could be summarized as follows: (1) arctic
or alpine vegetation zone: 0–15; (2) boreal or subalpine vegetation zone: 15-(50–55); (3) cool-temperate vegetation zone:
(50–55)–(80–90); (4) warm-temperate vegetation zone: (80–90)–(170–180). These values almost coincided with Kira's values.
Chinese postgraduate student in Japan sent by the Chinese Government. 相似文献
4.
Magdi M. Ali 《Hydrobiologia》2006,570(1):101-105
The paper reports on the flora along the banks of Lake Nubia and the long-term changes that have taken place since the formation
of the Aswan High Dam Lake 30 years ago. The study also aims to determine the main factors that govern plant distribution
in this area. Shoreline vegetation was studied from Debeira at the Sudanese–Egyptian border to the ‘Dal’ Cataract at the south
end of the lake, in Sudan. The shoreline was classified into four moisture gradient zones depending on the period of inundation,
namely: wet zone (frequently inundated and recently exposed); moist zone (periodically inundated); semi-dry zone (rarely inundated);
and dry zone (never inundated). Plants characterising each zone were identified. Soil texture and thickness of the deposits
were measured for each zone at each site. According to Grime’s strategy, the study revealed that species of the wet and the
moist zones are mainly disturbance-tolerant; species observed in the ‘semi-dry’ zone are competitive-stress-tolerant; and
those of the ‘dry’ zone are stress-tolerant. The present study indicates that elevation above mean sea level, and period of
inundation and texture of deposits play an important role in governing the distribution of the shoreline vegetation. 相似文献
5.
Jalil Noroozi Harald Pauli Georg Grabherr Siegmar-W. Breckle 《Biodiversity and Conservation》2011,20(6):1319-1338
This study provides a first country-wide overview of the vertical distribution patterns and the chorology of vascular plant
species that occur in the uppermost elevation zones in Iran. The current distribution patterns are discussed with respect
to potential warming-induced species losses. Iran’s subnival and nival vegetation zones are found at elevations above 3600–3900 m
in a highly fragmented distribution across Alborz, Zagros, and NW-Iran. Based on literature research and on field observations,
all vascular plant species living in the subnival–nival zone of Iranian mountains were identified (151 species) and classified
into three altitudinal groups: Group A comprises species that occur mainly in subnival–nival habitats (51 species). Group
B are species being common in subnival–nival areas but are equally present in the alpine zone (56 species). Group C are species
that can reach to subnival areas but also grow in alpine, subalpine and sometimes lower altitudes (44 species). The chorological
patterns differ among the three groups. The percentage of species being endemic to Iran decreases from group A, to B and C,
with 68, 53 and 20%, respectively. A narrow altitudinal distribution at high elevations is clearly related to a small-scaled
geographical distribution range. The outstanding rate of high-altitude endemism appears to result mainly from orographic isolation
of the country’s highly scattered cold areas and by the absence of extensive Pleistocene glaciations. The narrow distribution
of most of Iran’s cold-adapted mountain flora and the low potential of alternative cold habitats render it highly vulnerable
to climate change. 相似文献
6.
《Acta Oecologica》1999,20(3):209-217
An experiment was carried out from 1992 to 1995, in south-western Niger on a banded vegetation pattern which dominates on a laterite-capped plateau in the region. We quantified the changes in infiltration and vegetation in a thicket from which run-on from the upslope bare soil zone was artificially divested. A concrete wall (40 m long, 60 cm high, 20 cm thick, with a foundation 25 cm deep) was constructed at its upslope boundary. Infiltration was measured to a depth of 5.4 m by a neutron probe, and densities of annual plants were monitored along transects crossing perpendicularly a control thicket and the thicket deprived of run-on. Phenological phases and leaf water potential of the two dominant shrub species were recorded from stratified sampling according to their preferred location along the water resource gradient. Results indicated that run-on contributed the most to infiltration in the central zone, but the water content available to the annual plants (layer 0–10 cm) was not affected by run-on deprivation. Significant differences were found in the water content available to the shrubs (layer 0–100 cm) both between zones (upslope and central), and between thickets after the wall was built. However, in the thicket deprived of run-on, life cycle and physiology of the shrubs were severely disturbed upslope, while much smaller effects were observed in the centre. Surprisingly, within thestudy interval, run-on contribution was not found to be as essential to shrubs' life cycle at the location where it contributed the most to the infiltration. 相似文献
7.
Tracking rates of ecotone migration due to salt-water encroachment using fossil mollusks in coastal South Florida 总被引:1,自引:1,他引:0
Evelyn E. Gaiser Angelikie Zafiris Pablo L. Ruiz Franco A. C. Tobias Michael S. Ross 《Hydrobiologia》2006,569(1):237-257
We determined the rate of migration of coastal vegetation zones in response to salt-water encroachment through paleoecological
analysis of mollusks in 36 sediment cores taken along transects perpendicular to the coast in a 5.5 km2 band of coastal wetlands in southeast Florida. Five vegetation zones, separated by distinct ecotones, included freshwater
swamp forest, freshwater marsh, and dwarf, transitional and fringing mangrove forest. Vegetation composition, soil depth and
organic matter content, porewater salinity and the contemporary mollusk community were determined at 226 sites to establish
the salinity preferences of the mollusk fauna. Calibration models allowed accurate inference of salinity and vegetation type
from fossil mollusk assemblages in chronologically calibrated sediments. Most sediments were shallow (20–130 cm) permitting
coarse-scale temporal inferences for three zones: an upper peat layer (zone 1) representing the last 30–70 years, a mixed
peat-marl layer (zone 2) representing the previous ca. 150–250 years and a basal section (zone 3) of ranging from 310 to 2990
YBP. Modern peat accretion rates averaged 3.1 mm yr−1 while subsurface marl accreted more slowly at 0.8 mm yr−1. Salinity and vegetation type for zone 1 show a steep gradient with freshwater communities being confined west of a north–south
drainage canal constructed in 1960. Inferences for zone 2 (pre-drainage) suggest that freshwater marshes and associated forest
units covered 90% of the area, with mangrove forests only present along the peripheral coastline. During the entire pre-drainage
history, salinity in the entire area was maintained below a mean of 2 ppt and only small pockets of mangroves were present;
currently, salinity averages 13.2 ppt and mangroves occupy 95% of the wetland. Over 3 km2 of freshwater wetland vegetation type have been lost from this basin due to salt-water encroachment, estimated from the mollusk-inferred
migration rate of freshwater vegetation of 3.1 m yr−1 for the last 70 years (compared to 0.14 m yr−1 for the pre-drainage period). This rapid rate of encroachment is driven by sea-level rise and freshwater diversion. Plans
for rehydrating these basins with freshwater will require high-magnitude re-diversion to counteract locally high rates of
sea-level rise. 相似文献
8.
Changes in vegetation phenology directly reflect the response of vegetation growth to climate change. In this study, using the Normalized Difference Vegetation Index dataset from 1982 to 2015, we extracted start date of vegetation growing season (SOS), end date of vegetation growing season (EOS), and length of vegetation growing season (LOS) in the middle and eastern Eurasia region and evaluated linear trends in SOS, EOS, and LOS for the entire study area, as well as for four climatic zones. The results show that the LOS has significantly increased by 0.27 days/year, mostly due to a significantly advanced SOS (?0.20 days/year) and a slightly delayed EOS (0.07 days/year) over the entire study area from 1982 to 2015. The vegetation phenology trends in the four climatic zones are not continuous throughout the 34‐year period. Furthermore, discrepancies in the shifting patterns of vegetation phenology trend existed among different climatic zones. Turning points (TP) of SOS trends in the Cold zone, Temperate zone, and Tibetan Plateau zone occurred in the mid‐ or late 1990s. The advanced trends of SOS in the Cold zone, Temperate zone, and Tibetan Plateau zone exhibited accelerated, stalled, and reversed patterns after the corresponding TP, respectively. The TP did not occurred in Cold‐Temperate zone, where the SOS showed a consistent and continuous advance. TPs of EOS trends in the Cold zone, Cold‐Temperate zone, Temperate zone, and Tibetan Plateau zone occurred in the late 1980s or mid‐1990s. The EOS in the Cold zone, Cold‐Temperate zone, Temperate zone, and Tibetan Plateau zone showed weak advanced or delayed trends after the corresponding TP, which were comparable with the delayed trends before the corresponding TP. The shift patterns of LOS trends were primarily influenced by the shift patterns of SOS trends and were also heterogeneous within climatic zones. 相似文献
9.
A greenhouse experiment was conducted to study the uptake and translocation of N applied at different rates of15N fertilizer to the fruiting and rooting zones of peanut plants.
Higher N level treatments in the fruiting zone resulted in higher N concentrations in the shell and gynophore with fruit and
lower N concentration in the testa when compared with the results of lower level treatments in the fruiting zone. Regardless
of N levels applied in both rooting and fruiting zones, about 60–65% of15N application to the rooting zone was absorbed through the root, of which 30–35% was found in the seed. With fertilizer application
to the fruiting zone and regardless of levels applied to both zones, 35–40% of the15N supplied was absorbed through the shell, and 65% of this remained in the fruit parts while 35% of it was translocated to
the vegetation and roots. The percentage of N in the vegetative and root parts, derived from the fertilizer-15N through the shell, was lower in the root and nodules than in the shoot and gynophore without fruit. The translocation of
N, absorbed through the roots, to the fruit as well as the amount of symbiotically fixed N were decreased by additions of
N to the fruiting zone. 相似文献
10.
We assessed the seasonal abundance and distribution of Vibrio species as well as some selected environmental parameters in the treated effluents of two wastewater treatment plants (WWTP),
one each located in a suburban and urban community of Eastern Cape Province, South Africa. Vibrio population density ranged from 2.1×105 to 4.36×104 CFU/ml in the suburban community and from 2.80×105 to 1.80×105 CFU/ml in the urban community. Vibrio species associated with 180 μ, 60 μ, and 20 μ plankton sizes were observed at densities of 0–136×103 CFU/ml, 0–8.40×102 CFU/ml, and 0–6.80×102 CFU/ml, respectively at the suburban community’s WWTP. In the urban community, observed densities of culturable Vibrio were 0–2.80×102 CFU/ml (180 μ), 0–6.60×102 CFU/ml (60 μm), and 0–1.80× 103 CFU/ml (20 μm). The abundance of free-living Vibrio species ranged from 0 to 1.0×102 and 1.0×103 CFU/ml in the suburban and urban communities’ WWTPs, respectively. Molecular confirmation of the presumptive Vibrio isolates revealed the presence of V. fluvialis (41.38%), V. vulnificus (34.48%), and V. parahaemolyticus (24.14%) in the suburban community effluents. In the urban community molecular confirmation revealed that the same species
were present at slightly different percentages, V. fluvialis (40%), V. vulnificus (36%), and V. parahaemolyticus (24%). There was no significant correlation between Vibrio abundance and season, either as free-living or plankton-associated entities, but Vibrio species abundance was positively correlated with temperature (r=0.565; p<0.01), salinity, and dissolved oxygen (p<0.05). Turbidity and pH showed significant seasonal variation (p<0.05) across the seasons in both locations. This study underscores the potential of WWTPs to be sources of Vibrio pathogens in the watershed of suburban and urban communities in South Africa. 相似文献
11.
East China lies in the subtropical monsoon climatic zone and is dominated by subtropical evergreen broad-leaved forests, a
unique vegetation type mainly distributed in East Asia with the largest distribution in China. It is important to be able
to monitor and estimate forest biomass and production, regional carbon storage, and global climate change impacts on these
important vegetation types. In this paper, we used coarse resolution remote sensing data to identify the vegetation types
in East China and developed a map of the spatial distribution of vegetation types in this region. Nineteen maximum normalized
difference vegetation index (NDVI) composite images (acquisition time span of 7 months from February to August), which were
derived from 10 days National Oceanographic and Atmospheric Administration (NOAA) Advanced Very High Resolution Radiometer
(AVHRR) channel 1 and channel 2 observations, an unsupervised classification method, and the ISODATA algorithm were employed
to identify the vegetation types. To reduce the dimensions of the dataset resulted in a total of 28 spectral clusters of land-cover
of which two clusters were urban/bare soil and water, the images were processed using principal component analysis (PCA).
The 26 remaining spectral clusters were merged into six vegetation types using the Chinese vegetation taxonomy system: evergreen
broad-leaved forest, coniferous forest, bamboo forest, shrub-grass, aquatic vegetation, and agricultural vegetation. The spatial
distribution and areal extent for the coniferous forests, shrub-grass, evergreen broad-leaved forests, and agricultural vegetation
were calculated and compared with the Vegetation Atlas of China at a 1:1,000,000 scale. The spatial accuracy and the area
accuracy for coniferous forests, shrub-grass, evergreen broad-leaved forests, and agricultural vegetation were 79.2%, 91.3%,
68.2% and 95.9% and 92.1%, 95.9%, 63.8% and 90.5%, respectively. The spatial accuracy and area accuracy of the bamboo forest
were 28.7% and 96.5%, respectively; the spatial accuracy of aquatic vegetation was 69.6%, but there was a significant difference
in its area accuracy because image acquisition did not cover the full year. Our study demonstrated the feasibility of using
NOAA-AVHRR to identify the different vegetation types in the subtropical evergreen broad-leaved forest zone in East China.
The spatial location of the six identified vegetation types agreed with the actual geographical distribution of the vegetation
types in East China.
__________
Translated from Acta Phytoecologica Sinica, 2005, 29(3): 436–443 [译自: 植物生态学报, 2005, 29(3): 436–443] 相似文献
12.
The paper presents the results of an examination of the phycical-chemical parameters of water together with an analysis of
the chlorophyll a concentration of 12 small water bodies situated within urban and suburban areas of the city of Poznań (mid-west Poland)—typical
mid-forest, strongly anthropogenically modified in the urban landscape, strongly antropogenically modified in an agricultural
area and clay-pits. There were zones of open water (Unvegetated Zone) as well as zones of rush and aquatic vegetation (Vegetated
Zone) distinguished in the examined ponds. The influence of the rush vegetation, nymphaeids and elodeids on the abiotic parameters
of an aquatic environment was examined. Water samples were taken during the summer of 2004 from 12 stations within the open
water and 24 within macrophytes. The plant matter was randomly collected in triplicate from the central part of the vegetated
stand. The influence of macrophytes on the abiotic features of water was estimated using the parameter of the plant length
(cm l−1) and the plant biomass (g l−1). In the studied ponds 12 aquatic macrophyte communities were distinguished. A salient feature of submerged macrophytes was
a great density of plant stems along with considerebly low biomass, however, the rush vegetation (Phragmitetum communis, Typhetum latifoliae) when compared to nymphaeids (Polygonetum natantis, Potametum natantis) and elodeids (Potametum lucentis) was characterised by lower stem densities and higher biomass. The water bodies were alkaline and of pronounced hardness.
In most of them high trophy conditions were found with especially high concentrations of phosphorus (96 μg l−1 on average). There was significant differentiation in the water chemistry (mainly in respect to mineral compounds) between
the Vegetated and Unvegetated Zones as well as between particular aquatic macrophyte communities. 相似文献
13.
Tropical mangrove forests are characterized by clear zonation along a tidal gradient, and it has been supposed that the zonation is primarily controlled by soil factors. However, effects of disturbance on mangrove forests are still not well understood and may play an important role on the vegetation patterns and forest dynamics in some forest formations. In this study, the pattern of disturbance regime and its effects on regeneration of tropical mangrove forests along a tidal gradient were investigated in Ranong, Thailand. We established one or two 0.5 ha plots in four vegetation zones, i.e. Sonneratia alba–Avicennia alba zone, Rhizophora apiculata zone, Ra – Bruguiera gymnorrhiza zone, Ceriops tagal–Xylocarpus spp. zone. Gap size (percentage gap area to total study area and individual gap size) was the largest in Sa–Aa zone which is located on the most seaward fringe, and it declined from seaward to inland. Canopy trees of S. alba and A. alba had stunted trunks and showed low tree density. On the contrary, canopy dominants in the other three inland zones, e.g. R. apiculata, B. gymnorrhiza, and Xylocarpus spp., had slender trunks and showed high tree density. Accordingly, differences in disturbance regime among the four zones were resulted from the forest structural features of each zone. Disturbance regime matched with regeneration strategies of canopy dominants. Seedlings and saplings of S. alba and A. alba, which need sunny condition for their growth, were abundant in gaps than in understorey. By contrast, R. apiculata, B. gymnorrhiza, and Xylocarpus spp., which can tolerate less light than S. alba and A. alba, had greater seedling and sapling density under closed canopy than gaps. Many large gaps may enhance the abundance of S. alba and A. alba in Sa–Aa zone, and a few small gaps may prevent the light demanding species to establish and grow in the other inland zones. Correspondence of disturbance regime and regeneration strategies (e.g. light requirement) of canopy dominants may contribute to the maintenance of the present species composition in each of the vegetation zones. 相似文献
14.
Geographical variation in the diet of sika deer Cervus nippon Temminck, 1838 has been well characterised: northern populations are grazers, whereas southern deer are browsers. This variation
largely reflects genetic-based differences in morphology. However, environmental factors would be also important. If a same
genetic population live in different habitats, we can check altitudinal shifts in sika deer food consumption. We hypothesised
that changes in the diet of the sika deer population on the Izu Peninsula, which is located within the transitional zone of
resource (vegetation) variation and encompasses a broad altitudinal range, would mirror shifts in the composition of vegetation.
Analyses of the rumen contents of the deer population indicated that dwarf bamboo accounted for 10.5, 46.2, and 74.3% of the
deer diet in the low (<800 m), middle (800–1000 m), and high (>1000 m) altitudinal zones, respectively. In contrast, evergreen
broad-leaved species accounted for 35.7, 23.1, and 5.9%, respectively. These results suggest that the diet of sika deer is
more strongly affected by environmental factors, such as plant community composition, than by genetic factors. 相似文献
15.
Climate and vegetation in China IV. Distribution of tree species along the thermal gradient 总被引:4,自引:0,他引:4
The aim of this study was to examine correlations between vegetational zones and thermal climate on the basis of analysis
of the thermal distribution of main-component trees in each zone. The whole and main thermal distribution ranges for 73 tree
species were obtained from their distributions along the warmth index (WI) gradicnt. Cluster analysis using the WI values
at the upper and lower limits of the main distribution ranges as parameters gave seven species groups. The geographical distributions
of the species in each group were described. Moreover, the frequency distribution curves of the seven species groups were
determined along the WI grandient, and four borderlines (lines I, II, III and IV) were found among them. The WI values at
the lines I, II and IV were 50, 90, 175°C month, respectively, and corresponded to boundaries between the subarctic and cool-temperate
zones (I), the cool-and warm-temperate zones (II) and the warmtemperated and subtropical/tropical zones (IV), respectively.
Line III corresponded to a WI of 135°C month. The WI values at the forest limit and at the lower limit of the subarctic forest
were estimated, and their averages were 15.2 and 49.6°C month, respectively. In conclusion, thermal climatic zones in China
could be divided by the following WI values: alpine (arctic) zone, WI<15; subarctic zone, 15–50; cool-temperate zone, 50–90;
warm-temperate zone, 90–175; subtropical/tropical zone >175°C month. 相似文献
16.
We studied species richness, composition, and vertical distribution of vascular epiphytes at two sites in the Bolivian Andes.
To account for the epiphyte flora on understory trees, epiphytes on shrubs and small trees were sampled in 20 × 20 m2 subplots around each sampled canopy tree; this understory zone U is introduced as an addition to the well-established five
vertical Johansson tree zones. More than 20% of about 500 species recorded were found only in the understory subplots, including
ca. 40% of aroids, 35%–40% of piperoids, and 25%–30% of ferns. Habitat generalists (occurring in three or more zones) were
most common, contributing about 50% of all species, specialists (occurring only in two zones, or in three continuous ones)
34%–42%, and hemiepiphytes 6%–16%. Canopy epiphytes (occurring > 90% in tree zones Z3–5) were mainly represented by orchids
and ferns, many with special adaptations to drought stress such as pseudobulbs, succulence, and poikilohydry. Trunk epiphytes
( > 90% in understory and tree zones Z1–2) reached highest relative species numbers among piperoids and ferns. Most hemiepiphytes
were also trunk epiphytes, due to their characteristic growth pattern, and included mainly aroids. The vertical distribution
of epiphytes within a tree is determined by several microenvironmental gradients, with light intensity, wind speed, and air
temperature increasing and air humidity decreasing from the ground level to the canopy. 相似文献
17.
Pudas E Leppälä M Tolvanen A Poikolainen J Venäläinen A Kubin E 《International journal of biometeorology》2008,52(4):251-259
Timing of plant phenophases is a useful biological indicator which shows how nature responds to the variation in climate.
Thus, long phenological observation series help to estimate the impact of changing climate on forest plants. We investigated
whether phenological patterns of downy birch Betula pubescens respond to warming climate and whether the intensity of the responses varies among phytogeographical zones. We studied data
collected by the Finnish National Phenological Network from 30 observation sites across Finland during 1997–2006. The advancement
in the timing of the earliest phenophase, bud burst, ranged from 0.7 days/year in southern boreal zone to 1.4 days/year in
middle and northern boreal zones. Timing of bud burst was most clearly dependent on mean May temperatures. The intensity of
the response to temperature increased from south to north. The advancement of bud burst resulted into a significant lengthening
of the growth period by 1.2–1.6 days per year in northern and middle boreal zones, respectively, whereas the lengthening was
not significant in the southern boreal zone. No trend was observed in the timing of autumn phenophases. 相似文献
18.
Modern pollen representation of source vegetation in the Qaidam Basin and surrounding mountains, north-eastern Tibetan Plateau 总被引:3,自引:0,他引:3
We use a data set of 35 surface pollen samples from lake sediments, moss polsters and top soils on the north-eastern Tibetan
Plateau to explore the relationship between modern pollen assemblages and contemporary vegetation patterns. The surface pollen
transect spanned four vegetation zones––alpine meadow, steppe, steppe desert and desert––under different climatic/elevational
conditions. Relative representation (R
rel) values and Principal Components Analysis (PCA) were used to determine the relationships between modern pollen and vegetation
and regional climate gradients. The results show that the main vegetation zones along the regional and elevational transects
can be distinguished by their modern pollen spectra. Relative to Poaceae, a high representation of Artemisia, Nitraria and Chenopodiaceae was found, while Cyperaceae and Gentiana showed values in the middle range, and Ranunculaceae, Asteraceae, Ephedra and Fabaceae had low relative representation values. PCA results indicate a high correlation between the biogeoclimatic zones
and annual precipitation and annual temperature and July temperature. The Artemisia/Chenopodiaceae ratio and the Artemisia/Cyperaceae ratio are useful tools for qualitative and semi-quantitative palaeoenvironmental reconstruction on the north-eastern
Tibetan Plateau. Surface lake sediments are found to have different palynomorph spectra from moss cushion and soil samples,
reflecting the larger pollen source area in the contemporary vegetation for lakes. 相似文献
19.
Shinichi Yoshihiro Masaru Ohtake Hajime Matsubara Koichiro Zamma Goro Han'ya Yasuaki Tanimura Hiroyuki Kubota Ritsuko Kubo Tatsuhiro Arakane Toru Hirata Mari Furukawa Aki Sato Yukio Takahata 《Primates; journal of primatology》1999,40(2):409-415
A census of wild Yakushima macaques (Macaca fuscata yakui) was carried out in a 23-km2 area of the western coast of Yakushima Island, Japan. We analyzed the census data to investigate changes in monkey distribution
associated with the vertical distribution of vegetation. In the lowland coastal zone of 0–300 m above sea level (a.s.l.),
4.8 troops and 62.4–99.8 monkeys are estimated to have existed per km2. In the mountainside zones of 300–900 m a.s.l., the troop density decreased to 1.3–1.6 troops/km2. Since there was no difference in size between the coastal and mountainside troops, population density should decrease with
altitude to about 30–36 monkeys per km2. On the other hand, 2.4 troops and about 36 monkeys were estimated to have inhabited per km2 in the mountain summit zone of 900–1,323 m a.s.l.
Nature Conservation College 相似文献
20.
Soil Microbial Community Response to Drought and Precipitation Variability in the Chihuahuan Desert 总被引:2,自引:0,他引:2
Jeb S. Clark James H. Campbell Heath Grizzle Veronica Acosta-Martìnez John C. Zak 《Microbial ecology》2009,57(2):248-260
Increases in the magnitude and variability of precipitation events have been predicted for the Chihuahuan Desert region of
West Texas. As patterns of moisture inputs and amounts change, soil microbial communities will respond to these alterations
in soil moisture windows. In this study, we examined the soil microbial community structure within three vegetation zones
along the Pine Canyon Watershed, an elevation and vegetation gradient in Big Bend National Park, Chihuahuan Desert. Soil samples
at each site were obtained in mid-winter (January) and in mid-summer (August) for 2 years to capture a component of the variability
in soil temperature and moisture that can occur seasonally and between years along this watershed. Precipitation patterns
and amounts differed substantially between years with a drought characterizing most of the second year. Soils were collected
during the drought period and following a large rainfall event and compared to soil samples collected during a relatively
average season. Structural changes within microbial community in response to site, season, and precipitation patterns were
evaluated using fatty acid methyl ester (FAME) and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE)
analyses. Fungal FAME amounts differed significantly across seasons and sites and greatly outweighed the quantity of bacterial
and actinomycete FAME levels for all sites and seasons. The highest fungal FAME levels were obtained in the low desert scrub
site and not from the high elevation oak–pine forests. Total bacterial and actinomycete FAME levels did not differ significantly
across season and year within any of the three locations along the watershed. Total bacterial and actinomycete FAME levels
in the low elevation desert-shrub and grassland sites were slightly higher in the winter than in the summer. Microbial community
structure at the high elevation oak–pine forest site was strongly correlated with levels of NH4
+–N, % soil moisture, and amounts of soil organic matter irrespective of season. Microbial community structure at the low elevation
desert scrub and sotol grasslands sites was most strongly related to soil pH with bacterial and actinobacterial FAME levels
accounting for site differences along the gradient. DGGE band counts of amplified soil bacterial DNA were found to differ
significantly across sites and season with the highest band counts found in the mid-elevation grassland site. The least number
of bands was observed in the high elevation oak–pine forest following the large summer-rain event that occurred after a prolonged
drought. Microbial responses to changes in precipitation frequency and amount due to climate change will differ among vegetation
zones along this Chihuahuan Desert watershed gradient. Soil bacterial communities at the mid-elevation grasslands site are
the most vulnerable to changes in precipitation frequency and timing, while fungal community structure is most vulnerable
in the low desert scrub site. The differential susceptibility of the microbial communities to changes in precipitation amounts
along the elevation gradient reflects the interactive effects of the soil moisture window duration following a precipitation
event and differences in soil heat loads. Amounts and types of carbon inputs may not be as important in regulating microbial
structure among vegetation zones within in an arid environment as is the seasonal pattern of soil moisture and the soil heat
load profile that characterizes the location. 相似文献