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1.
Maintenance of ecosystem health is the primary focus of a sound ecological restoration.Yet methods involved in quantifying and assessing the health level remain a challenge to the ecological community.In this study,we selected the hill and gully area of Loess Plateau,Inner Mongolia,China,as our study area.The soil and water erosions in this area continue to be responsible for many environmental problems in northern China because of its fragility and long disturbance history.In this study,we developed an assessment method of indicator system(AMIS)based on analytical hierarchy process(AHP),fuzzy mathematics.and the theory of net-hierarchy.At ecosystem or catchment scale,three sample areas,that is(1)intact vegetation(i.e., Aguimiao Natural Reserve,110°45'E,39°28'N),(2)reconstructed vegetation(Wufendigou Soil and Water Conservation Experimental Area,111°07'E 39°45'N),and (3)severely degraded vegetation(Yangquangou Catchment,111°06'E,39°45'N)in the hill and gully area of Loess Plateau in Inner Mongolia.China.were selected to examine ecosystem vigor,organizational structure,service function,and soil healm.We applied the AMIS for all three landscapes by categorizing each ecosystem into five health levels.Wle found that the health index for reconstructed vegetation were at levels of Ⅳ,Ⅱ,Ⅳ,and Ⅲ,while those of degraded vegetation were ranked at Ⅴ,Ⅳ,Ⅴ,and Ⅳ.Overall.the comprehensive ecosystem health index of reconstmcted vegetation was lower than that of intact vegetation but higher than that of degraded vegetation.The health index for reconstructed vegetation was at level Ⅲ.and that of degraded vegetation was still at level Ⅳ.The contributing values were:organization structure>soil health>vigor>service function.Based on our results and assessments,we proposed several management recommendations and methods for restoring the regional ecosystems. 相似文献
2.
M. C. L. Cohen J. T. F. Guimarães M. França R. J. Lara H. Behling 《Wetlands Ecology and Management》2009,17(2):145-155
Two sediment cores sampled from a varzea (N 02°34′38′′, W 50°53′17′′) and mangrove area (N 02°35′59′′, W 50°52′08′′) in Amapá
littoral, northern Brazil, were studied through pollen and spectrophotometric analysis in order to compare biological and
chemical signals of mangrove vegetation recorded by sediments during the late Holocene. According to the pollen study, probably
the core base (145–65 cm) of varzea vegetation accumulated sediments devoid of vegetation. Later, this site was dominated
by herbaceous vegetation and it concluded with a varzea forest. Based on spectrophotometric analysis, this core did not present
significant tannin concentrations. This is likely due to the mangrove absence during the vegetation development at this site.
The core sampled from a mangrove area also presented a relationship between palaeovegetation and the sediment biogeochemistry.
However, the mangrove core presented significant tannin content along the mangrove phases. Thus, this spectrophotometric method
supported by the pollen data may be considered as a complementary tool to identify palaeomangrove deposits. 相似文献
3.
Cesar França Braga Viviane Ferreira Monteiro José Souto Rosa-Filho Colin Robert Beasley 《Wetlands Ecology and Management》2011,19(3):257-272
The composition and abundance of the poorly known benthic macroinfauna associated with northern Brazilian saltmarshes, were
described from eight sites (between 0°42′2.5″S, 47°52′44.1″W and 0°50′17.3″S, 46°36′13.3″W) along the Pará coast, Brazil.
Sampling was carried out in November of 2007. Univariate and multivariate analyses were used to test for differences in sediment,
vegetation and macroinfaunal variables among sites. No vertical zonation of the macroinfauna was detected. Macroinfaunal structure
differed greatly among sites with different sediment and vegetation characteristics. Number of individuals and taxa were low
in sites with sandy sediments and short, sparse vegetation and high in those with silty sediments with high organic matter
and water contents, and tall, dense vegetation. Increasing number of individuals and taxa were associated with a geographical
gradient in pore water salinity, which increases from west to east, coinciding with patterns of rainfall described for the
Pará coast. 相似文献
4.
We asked whether vegetation mapping repeated after 70 years revealed vegetation changes in the high Arctic. The study site
is located at 78°38′N, 16°45′E, near Brucebyen at the Adolfbukta Bay (head of Billjefjorden) in central Spitsbergen (Svalbard),
and encompasses an area of 2,042 × 521 m. The mapping carried out in 2008 did not reveal any changes in vegetation, since
a previous study in 1936–1937, that could be attributed to climate change. We argue that our finding can be interpreted as
evidence of a slow ecological response of constituent plants in such a harsh environment. Moreover, geographic isolation may
limit establishment and expansion of new species. Some successional changes were only due to erosion–accumulation processes
connected especially to stream activity. 相似文献
5.
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
6.
Autolytic degradation of yeast RNA occurs in many foods and beverages and can impact on the sensory quality of the product,
but the resulting complex mixture of nucleotides, nucleosides and nucleobases has not been properly characterised. In this
study, yeast autolysis was induced by incubating cell suspensions of Saccharomyces cerevisiae at 30–60 °C (pH 7.0), and at pH 4.0–7.0 (40 °C) for 10–14 days, and the RNA degradation products formed during the process
were determined by reversed-phase HPLC. Up to 95% of cell RNA was degraded, with consequent leakage into the extracellular
environment of mainly 3′-, 5′- and 2′-ribonucleotides, and lesser amounts of polynucleotides, ribonucleosides and nucleobases.
The rate of RNA degradation and the composition of the breakdown products varied with temperature and pH. RNA degradation
was fastest at 50 °C (pH 7.0). Autolysis at lower temperatures (30 °C and 40 °C) and at pH 5.0 and 6.0 favoured the formation
of 3′-nucleotides, whereas autolysis at 40 °C and 50 °C (pH 7.0) favoured 5′- and 2′-nucleotides. The best conditions for
the formation of the two flavour-enhancing nucleotides, 5′-AMP and 5′-GMP, were 50 °C (pH 7.0) and pH 4.0 (40 °C), respectively. 相似文献
7.
The seasonal variation in the foraging behaviour of king penguins (Aptenodytes patagonicus) was studied at Heard Island (53°05′S, 73°30′E) during 1992/1993. On seven occasions throughout the breeding cycle, time-depth-light
recorders were deployed on breeding adults to record the dive activities and foraging. Foraging locations changed with season:
in autumn and spring 1992, adults foraged between 48–52°S and 74–78°E, about 370 km NNE of Heard Island close to the Polar
Front. Two penguins tracked in winter travelled 2220 km east of Heard Island (95°E) along the northern ice limit, and 1220 km
south of Heard Island to approximately 65°S, respectively. In spring (October), the penguins again foraged further north than
during winter. The foraging area utilised in October overlapped the area where the penguins foraged in March/April. The penguins'
diving behaviour also varied seasonally: the modal depth of deep dives (>50 m) increased from about 100 m in February to 220 m
in October. Mean dive depths increased from 70 ± 52 m in March 1992 to 160 ± 68 m in August 1992. Penguins dived deep (>50 m)
only during daylight hours (16 h in February, 9 h in July). Mean dive durations ranged from 2.9 ± 1.1 min in March 1992 to
5.1 ± 1.2 min in August 1992. Associated with changes in foraging location and dive behaviour was a change in diet composition:
during summer the penguins ingested mainly myctophid fish (>90%) while in winter the most important diet item was squid.
Accepted: 19 October 1998 相似文献
8.
Vegetation classification is an important topic in plant ecology and many quantitative techniques for classification have
been developed in the field. The artificial neural network is a comparatively new tool for data analysis. The self-organizing
feature map (SOFM) is powerful tool for clustering analysis. SOFM has been applied to many research fields and it was applied
to the classification of plant communities in the Pangquangou Nature Reserve in the present work. Pangquangou Nature Reserve,
located at 37°20′–38°20′ N, 110°18′–111°18′ E, is a part of the Luliang Mountain range. Eighty-nine samples (quadrats) of
10m × 10m for forest, 4m × 4 m for shrubland and 1m × 1m for grassland along an elevation gradient, were set up and species
data was recorded in each sample. After discussion of the mathematical algorism, clustering technique and the procedure of
SOFM, the classification was carried out by using NNTool box in MATLAB (6.5). As a result, the 89 samples were clustered into
13 groups representing 13 types of plant communities. The characteristics of each community were described. The result of
SOFM classification was identical to the result of fuzzy c-mean clustering and consistent with the distribution patterns of
vegetation in the study area and shows significant ecological meanings. This suggests that SOFM may clearly describe the ecological
relationships between plant communities and it is a very effective quantitative technique in plant ecology research.
__________
Translated from Acta Ecologica Sinica, 2007, 27(3): 1005–1010 [译自: 生态学报] 相似文献
9.
S. P. Kharitonov D. J. Nowak A. I. Nowak N. A. Egorova S. A. Korkina D. V. Osipov O. V. Natalskaya 《Biology Bulletin》2009,36(6):643-646
Studies were carried out in 2000–2007 near Medusa Bay (73°21′N, 80°32′ E) and along the Agapa River (from 70°11′N, 86°15′
E. down to the mouth 71°26′ N, 89°13′ E), in the northwestern and central parts of the Taimyr Peninsula. White-fronted goose
nests are usually spread in the tundra or placed in 1–3 nest colonies near nests or staging points of snowy owls, peregrine
falcons, or rough-legged buzzards. The intent of white-fronted geese to breed near birds of prey or owls increases sharply
when arctic fox numbers are high. In the area near Medusa Bay, white-fronted geese nest much closer to peregrine falcon nests
than in the area along the Agra River. At the latter location, white-fronted geese lose the competition to red-breasted geese,
which are more numerous here. Bean geese, in spite of their greater size and ability to protect their nests against arctic
foxes, really tend to breed near peregrine falcons or buzzards, where they manage to compete with red-breasted geese. 相似文献
10.
Lisi Dámaris Pereira Alvarenga Kátia Cavalcanti Pôrto Juliana Rosa do Pará Marques de Oliveira 《Biodiversity and Conservation》2010,19(3):619-635
The vertical distribution of the richness, abundance, and composition of epiphytic bryophytes was studied in a matrix of fragmented
habitats in the Brazilian Atlantic rainforest of the Murici Ecological Station (9°11′05″–9°16′48″ S, 35°45′20″–35°55′12″ W),
northeastern Brazil. The aim was to compare the horizontal (between sites) and vertical (between phorophyte heights) turnover
to test a hypothesis based on niche width vulnerability. There was a highly significant decreasing of richness accompanying
the loss of habitat, and the most conserved fragment housed a total richness more than 10 times higher than the less conserved
fragment. Epiphytes failed to colonize lower trunks (2.1–10 m) and higher zones in most of the non-conserved fragments; they
were restricted to the base (0–2 m) and displayed a clear altered floristic composition. The species with restricted ecological
amplitudes such as sun and shade tolerant taxa were more negatively affected by habitat loss than generalists. Although the
mean richness of generalists decreased in non conserved fragments, the proportional contribution of this guild increased,
proving that these taxa are the ones which persist in disturbed sites. The forest fragments capable of harboring rich epiphyte
flora in the area studied are over 300 ha in size, which is far from being a common size among Brazilian Atlantic rainforest
fragments. Hence, our results highlight the need of conserving the few large remnants in this ecosystem. 相似文献
11.
Forests play a major role in global carbon (C) cycle, and the carbon density (CD) could reflect its ecological function of
C sequestration. Study on the CD of different forest types on a community scale is crucial to characterize in depth the capacity
of forest C sequestration. In this study, based on the forest inventory data of 168 field plots in the study area (E 111°30′–113°50′,
N 37°30′–39°40′), the forest vegetation was classified by using quantitative method (TWINSPAN); the living biomass of trees
was estimated using the volume-derived method; the CD of different forest types was estimated from the biomass of their tree
species; and the effects of biotic and abiotic factors on CD were studied using a multiple linear regression analysis. The
results show that the forest vegetation in this region could be classified into 9 forest formations. The average CD of the
9 forest formations was 32.09 Mg ha−1 in 2000 and 33.86 Mg ha−1 in 2005. Form. Picea
meyeri had the highest CD (56.48 Mg ha−1), and Form. Quercus liaotungensis + Acer mono had the lowest CD (16.14 Mg ha−1). Pre-mature forests and mature forests were very important stages in C sequestration among four age classes in these formations.
Forest densities, average age of forest stand, and elevation had positive relationships with forest CD, while slope location
had negative correlation with forest CD. 相似文献
12.
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
13.
Mariela Gómez-Romero Roberto Lindig-Cisneros Sebastiana Galindo-Vallejo 《Plant Ecology》2006,183(2):207-213
Plant establishment on sites affected by major volcanic disturbances is limited by several factors, such as lack of suitable
microsites for germination and establishment in sites affected by tephra from volcanic eruptions. Even after long periods
of time, tephra deposited over un-vegetated areas (agricultural fields and other barren areas) lack closed vegetation cover
and in many cases late successional species. To assess limiting factors for plant establishment, a field survey in a tephra
deposit from the Paricutin volcano eruption (19°30′42.4′′ N, 102°12′03.0′′) and greenhouse experiments were carried out. The
field survey determined the relationship between tephra depth and vegetation distribution. Greenhouse experiments determined
the effect of tephra depth on establishment and growth of two dominant species in the tephra deposit surveyed, Eupatorium glabratum and Lupinus elegans. Our results suggest that size and spatial distribution of vegetation patches is related to tephra depth in the field (77%
of the vegetation patches were on tephra 38.8 cm deep or less and only 2% on tephra of more than 46.8 cm). Under greenhouse
conditions, Eupatorium glabratum and Lupinus elegans height sharply decreased as depth of the tephra layer increased. Lupinus elegans plants growing in tephra less than 30 cm deep had a mean weight of 10.56 g (±0.53 g) compared with 3.11 g (±0.46 g) for plants
growing in tephra more than 30 cm deep. Our results suggest that tephra depth is a limiting factor for canopy development
in barren areas affected by tephra deposition. 相似文献
14.
I. V. Pozdeev 《Inland Water Biology》2011,4(1):97-100
The distribution of Dreissena polymorpha in the northeastern part of the Kama River basin is limited to the area with the following geographic coordinates: 59°37′–54°00′
N and 57°10′–49°03′ E. The range of the zebra mussel is continuous along the Kama, Belaya, and Ufa rivers. Isolated populations
of this mollusk exist in the Belaya and Vyatka river floodplains. The distribution of dreissena in the running waters of the
Kama River basin is limited by the potamal conditions. 相似文献
15.
The thermodynamic parameters enthalpy and entropy of the interaction between calcium(II) or copper(II) with 5′-UMP, 5′-CMP,
5′-AMP, 5′-GMP or 5′-IMP in aqueous solution were determined calorimetrically (ionic strength adjusted to 0.1 with tetramethylammonium
bromide) at 25 °C and pH 7 for Ca(II) or pH 3–5 for Cu(II). The experimental conditions were carefully selected to avoid polynuclear
complex formation and nucleotide self-stacking. The calorimetric data confirm the tendency toward macrochelation which was
indicated by Sigel after very precise potentiometric studies, and which follows the order Cu(II)>Ca(II) for the metal ions
and GMP>IMP>AMP>CMP=UMP for the nucleotides. Macrochelate formation for these metal-nucleoside monophosphate complexes is
energetically favorable and entropically unfavorable.
Received: 13 August 1999 / Accepted: 1 February 2000 相似文献
16.
S. P. Kharitonov D. E. Nowak A. I. Nowak N. A. Egorova S. A. Korkina D. V. Osipov O. V. Natal’skaya 《Biology Bulletin》2009,36(5):469-478
Red-breasted goose colonies have been studied near Medusa Bay (73°21′N, 80°32′E), on the northwestern Taimyr Peninsula, and
along the Agapa River (70°11′N, 86°15′E) down to its mouth (71°26′N, 89° 13′E), in the central Taimyr Peninsula. Red-breasted
geese nesting near peregrine falcons are protected by the falcons from arctic foxes; however, they are sometimes attacked
by the falcons themselves. In the colonies near peregrine falcon nests, the vast majority of goose nests were situated no
farther than 100 m from the falcon nest. When food is abundant, falcons protect a larger area around their nest. The distance
between the falcon nest and the surrounding goose nests is inversely related to the falcon’s activity. In years of higher
falcon activity, falcons prevent red-breasted geese from nesting as close to their nest as in years of lower falcon activity.
Additional stimuli are required for red-breasted geese to form colonies near rough-legged buzzard nests. The distance between
snowy owl nests and red-breasted goose nests was smaller when arctic foxes were abundant than when they were scarce. 相似文献
17.
Antarctic terrestrial ecosystems are nutrient-poor and depend for their functioning in part on external nutrients. However,
little is known about the relative importance of various sources. We measured external mineral nutrient sources (wind blown
material, precipitation and guano) at three locations, the cold temperate oceanic Falkland Islands (51°76′S), and the Maritime
Antarctic Signy (60°71′S) and Anchorage Islands (67°61′S). These islands differ in the level of vegetation development through
different environmental constraints and historical factors. Total mineral nitrogen input differed considerably between the
islands. During the 3 month summer period it amounted to 18 mg N m−2 on the Falkland Islands and 6 and 102 mg N m−2 at Signy and Anchorage Islands, respectively. The high value for Anchorage was a result of guano deposition. By measuring
stable isotopic composition (δ15N) of the different nitrogen sources and the dominant plant species, we investigated the relative utilisation of each source
by the vegetation at each island. We conclude that external mineral nitrogen inputs to Antarctic terrestrial ecosystems show
great spatial variability, with the local presence of bird (or other vertebrate) colonies being particularly significant. 相似文献
18.
Hybridisation between South polar skua (C. maccormicki) and Brown skua (C. antarctica lonnbergi) in the area of the Antarctic Peninsula is known at least since the beginning of the last century but no survey has been
done so far. This paper reviews information on the species composition of skua colonies of more than 10 pairs in the Antarctic
Peninsula region, and the incidence of mixed pairs. Morphometrics, population size and breeding success were examined in detail
at King George Island. The northward distribution of South polar skuas extended to King George Island (62°11′ S 59°00′ W),
with a small outlying population on Signy Island (60°45′ S 45°36′ W), whereas Brown skuas did not breed further south than
Anvers Island archipelago (64°46′ S 64°03′ W). The proportion of mixed pairs was highest at the northern end of the ∼500-km-wide
hybrid zone. Body size distribution of sympatric skuas from King George Island is clearly bimodal but overlaps considerably
and hybrids cannot be identified. Skua population sizes at Potter Peninsula/King George Island remained stable between 1994
and 2004. Numbers of mixed breeding pairs fluctuated more strongly than those of pure species pairs. Breeding success of Brown
skuas varied the least. 相似文献
19.
The autolysis of yeast cells has practical implications in the production of fermented foods and beverages and flavourants
for food processing. Protein and RNA degradation during yeast autolysis are well described but the fate of DNA is unclear.
Yeast cells (Saccharomyces cerevisiae) were autolysed by incubating suspensions at 30–60°C (pH 7.0), and at pH 4.0–7.0 (40°C) for 10–14 days. Up to 55% of total
DNA was degraded, with consequent leakage into the extracellular environment of mainly 3′- and 5′-deoxyribonucleotides, and
lesser amounts of polynucleotides. The rate and extent of DNA degradation, composition of the DNA degradation products and
DNase activity were affected by temperature and pH. The highest amount of DNA degradation occurred at 40°C and pH 7.0, where
the highest DNase activity was recorded. DNase activity was lowest at 60°C and pH 4.0, where the proportion of polynucleotides
in the degradation products was higher.
Electronic Publication 相似文献
20.
Zeng Zhigao Song Yanling Ma Yingtai Wang Xifeng Wu Xuntao Xie Zhenfeng Shao Jianbin Li Chunning 《Frontiers of Biology in China》2007,2(1):92-99
Niubeiliang National Nature Reserve (NNR, 108°45′–109°04′E, 33°47′–33°56′N) is located on the eastern range of the Qinling
Mountains in Shaanxi Province, China and spans the southern and northern slopes of Mt. Qinling. A transect survey and investigation
were carried out in NNR to determine the fauna characteristics and ecological distribution of carnivora and artiodactyla from
May 2003 to August 2004. The NNR has 18 mammals (carnivore and artiodactyl), two of which belong to the first class and seven
to the second class of state key protected wildlife in China. The results of this study indicated that ungulates were abundant
in the NNR, as all ungulates that were distributed within Mt. Qinling could be found within the reserve. However, only 45.5%
of the carnivores distributed within Mt. Qinling were detected within the NNR. Among the mammals, there were 12 oriental species
(66.7%), 1 palearctic specie (5.5%) and 5 widely-distributed species (27.8%). The NNR is a crossing area of palearctic species
and oriental species on the zoogeographical regions, and it is a transitional area from the oriental realm to the palearctic
realm. The results of the analysis on the ecological distribution of carnivore and artiodactyl in the area showed that their
elevation ranges had large differences. The species whose elevation ranges above 1 300 m, about 1 000 m, and in 450–700 m
occupied one third respectively. The results also indicated that species richness for the memals in the NNR peaked at a middle
elevation (rising at first, then descending with the increase in elevation). Not only on the southern slope, but also on the
northern slope of Mt. Qinling, the number of species distributed in the area at 1 800–2 200 m a.s.l. was the largest (more
than 80%), while the number of species distributed in the area above 2 600 m a.s.l. was the smallest (about 50%). Elevation
gradients of species richness for the mammals in the NNR also embodied the mammal distributions among the vegetation types.
The number of species distributed in the mixed coniferous and broadleaf deciduous forest at middle elevations was the largest,
while the number of species distributed in the broadleaf deciduous forest at middle and low elevations, subalpine coniferous
forest, subalpine shrubbery and meadow was relatively smaller.
Translated from Acta Ecologica Sinica, 2005, 25(9): 2249–2255 [译自: 生态学报] 相似文献