全 文 ：应用与环境生物学报 2009，15 ( 4 ): 469~473
Chin J Appl Environ Biol=ISSN 1006-687X
2009-08-25
DOI: 10.3724/SP.J.1145.2009.00469
Many of ecotourism venues, such as national parks
and protected areas, are located in remote areas with rich
biological diversity and indigenous cultures. Traveling to
remote destinations to experience nature and indigenous
culture has become a growing phenomenon. Economic prospect
of interest in turning biodiversity into tourist at tractions
provides an opportunity to bridge the gap between natural
resource conservation and community development [1]. Though
development of tourism can be a way to make nature reserves
economically viable, and provide employment and income
for local population, it brings adverse impacts on ecological
environments also. Infrastructure construction and tourists’
behaviors have damaged forests in many aspects, which usually
starts from the locations of easy access or places with high
population pressure [2]. Many plant species and communities
appear to be threatened because of tourism disturbance [3]. The
relationship between tourism development and biodiversity
conservation has become a focus of research [4~6].
Considerable work has showed that tourism brings adverse
Effect of Tourism on Epiphytic Bryophyte Community Growing
on Abies faxoniana Trees in Primary Forests
in Jiuzhaigou, China*
YAN Xiaoli, BAO Weikai** & ZHU Zhu
(Key Laboratory of Ecological Restoration, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China)
旅游干扰对九寨沟原始森林岷江冷杉树干附生
苔藓植物组成和结构的影响*
闫晓丽 包维楷** 朱 珠
(中国科学院成都生物研究所生态恢复重点实验室. 成都 610041)
Abstract To determine the long-term effect of tourism on epiphytic bryophytes, species composition, coverage and biomass
of the bryophyte community growing on Abies faxoniana trees in primary forests in the Jiuzhaigou, a World Nature Heritage
site, in Sichuan, China were investigated. Difference in species composition on tree trunks in the two different areas was tested
by comparing dominant value of each species. Independent-samples t test analysis was used to examine richness, coverage and
biomass of the epiphytic bryophytes community along four tree trunk heights (20 cm, 50 cm, 120 cm and 180 cm) in the two
areas. The results showed: (1) there were signifi cant difference in species composition between the two areas. Hygrophilous
species disappeared partly, and disturbance-resistant species and exotic species expanded their populations in the tourism
area; (2) the community structure of bryophytes on the fir trunks in the tourism area was found simpler than that in the
undisturbed area; and (3) the trunk at height of 120 ~ 180 cm was more susceptible to disturbance, but the base was not affected
signifi cantly by disturbance. The results indicated that tourism disturbance altered species composition structure and biomass
mostly through indirect impacts. Mechanism of tourism impact on epiphytic bryophytes needs further study. It is necessary to
strengthen tourism management, limit the number of tourists and regulate the behaviors of tourists. Fig 2, Tab 3, Ref 25
Keywords Abies faxoniana; epiphytic bryophyte; independent-sample t test; tourism disturbance; tree-height gradient
CLC Q949.35 (271) : Q948.123
摘 要 附生苔藓植物是森林生物多样性的重要组分，对森林及其环境的质量有很好的指示作用. 为了揭示旅游活动
对森林及其环境的影响，调查了九寨沟原始森林景点内附近旅游活动频繁地段与未扰动地段原始林优势种岷江冷杉
(Abies faxoniana)树干4个高度附生苔藓种类的组成、生物量和群落结构，采用独立样本t检验对苔藓层结构参数进行
了差异性检验. 结果表明：(1) 冷杉树干附生苔藓物种组成在旅游活动频繁地段与未扰动地段有很大的差异. 在旅游
活动频繁地段，耐荫喜湿物种局部消失(重要值下降)，耐干旱抗干扰的植物种群扩大；(2) 旅游活动频繁地段树干附生
苔藓植物的丰富度、盖度和生物量较未扰动地段小；(3) 距地面较高的高度120 cm和180 cm处受到的干扰强度最大，基
部的影响较小. 旅游活动对附生苔藓植物的干扰主要为间接的环境影响，其机理还未充分认识，还需进一步研究. 综
合分析表明，旅游干扰影响了九寨沟的生态环境，需要进一步加强管理，控制游客数量和规范游客行为. 图2 表3 参25
关键词 岷江冷杉；附生苔藓；独立样本t检验；旅游干扰；树干高度
CLC Q949.35 (271) : Q948.123
Received: 2008-05-19 Accepted: 2008-07-24
*Supported by the National Natural Science Foundation of China (No.
30570333) and the National “11th Five- year Plan” Key Technology R & D
Program of China (No. 2006BAC01A15)
∗∗Corresponding author (E-mail: baowk@cib.ac.cn )
470 15 卷应 用 与 环 境 生 物 学 报 Chin J Appl Environ Biol
effect on vegetation [7~10]. The effect of tourism disturbance on
ground bryophytes, grasses and shrubs is locally serious, but on
arbors is not so obvious [11]. In terms of species composition, some
native shade-tolerant or hygrophilous species have disappeared,
while some xerophilous and disturbance-resistant species, as
well as some exotic and synanthropic species expand and become
dominant [12]. Plant diversity of community is affected by the
disturbance at different degrees. Heavy disturbance may lead to
decrease in diversity, while medium degree of disturbance can
promote diversity at a relatively high level [11].
The primary forests in the Jiuzhaigou are coniferous forests
dominated by A. faxoniana, including 125 herbaceous species
and 29 shrub species [12]. Epiphytic bryophytes heavily grow in
the forests. Cryptogams play an important role in the forests, not
only in species diversity, but also in ecosystem functioning [13].
Mats of cryptogams hold water, trap seeds, intercept and retain
nutrients from fog, and provide anchorage for seedlings [14~16]. Some
studies have examined that many understory plants in the primary
forests were threatened because of tourism disturbance [17, 18]. From
a view of biodiversity conservation, it is important to know how
epiphytic bryophytes are affected by tourism disturbance.
The present study aimed to detect the differences in the
composition and diversity of epiphytic bryophytes between
tourism area and undisturbed area. The following were done
in the this study: (1) to test the effect of tourism disturbance on
bryophyte species composition; and (2) to understand the changes
in bryophyte biomass and structure with tourism disturbance
at four different tree trunk heights (rasal, lower, middle and
upper), especially to test the hypothesis that epiphytic bryophytes
changed along tree trunk height gradient.
1 Methods
1.1 Study site description
The study site is located in A. faxoniana primary forests (3
060 m above sea level) in the Jiuzhaigou World Nature Heritage
site (between 32°54′ ~ 33°19 N and 103°46′ ~ 104°4′ E), in
Jiuzhaigou County, Aba Prefecture, Sichuan. The understory
shrubs in the A. faxoniana forests are rich in species and sparse
in distribution. The arbor layer has a canopy density of 0.8 and
its understory is dominated by Rhododendron spp., Rosa spp.,
Potentilla fruticosa and Spiraea myrtilloides. The coverage by
herbaceous plants is 30%, and the dominant species include
Fragaria orientalis, Oxalis corniculata, Circaea alpine subsp.
Imaicola, Carex spp. and numerous ferns. Ground bryophytes
are heavily developed and the dominant species are Thuidium
cymbifolium, Hylocomium splendens and Actinothuidium
hookeri. This area belongs to temperate monsoon climate. The
mean annual temperature is 7.8 ℃ and mean temperature is 17 ℃
in July. The mean sunshine time is about 1 900 h/year and mean
annual wind velocity is 1~2 m/s or so [19].
1.2 Assessment of tourism disturbance in Jiuzhaigou
This very beautiful place with natural vegetation and
wonderful lakes was found for the fi rst time in the early 1970s.
Jiuzhaigou was established as a forest park in 1978. Then, in
1982, it was listed as a national scenic spot of China, in 1992 as a
World Nature Heritage site by the UNESCO. In 1997, it joined in
Man and Biosphere Conservation Network. Due to fast tourism
development and wonderful subalpine landscapes, Jiuzhaigou has
become a hot spot for tourism in the world, and more and more
tourists both from China and abroad come here since then. At the
end of 2004, the number increased to 7 000 visitors per day on
average, with the largest of 12 000 reported during peak period.
From the date stated above, we can see that the pressure of
tourism disturbance was produced by the large-scale construction
of infrastructures and quick increase of tourists in this area.
In 2005, a fi eld investigation was conducted in one site of
the primary forest which is one of the most frequently visited
destinations and severely affected by the incorrect behaviors
(trampling, climbing and picking) of tourists and infrastructure
construction (eg. road and plank path). The vegetation along the
plank path became seriously degraded, and naked. Previous work
has also showed that tourism had produced negative infl uence on
plant diversity [20].
1.3 Vegetation sampling
The field investigation was done in summer of 2005. A
sampling site was set up along the path. The investigated site
was divided into two areas, tourism area and undisturbed area,
according to the distance from path. The choice of distance was
based on our own observation. The undisturbed area was situated
at a place of 150 m away from the path without human activity
Fig. 1 Design for the investigation in the primary forests (Each dot represents a studied tree)
4714 期 YAN Xiaoli, et al.：Effect of Tourism on Epiphytic Bryophyte Community Growing on Abies faxoniana Trees...
trails (Fig. 1). In each of the two areas, twenty trees with average
DBH (diameter at breast height) ranging between 122.14 cm and
127.44 cm were selected along the plank path (Table 1). Total
bryophytes coverage was estimated at four different heights from
ground, that is, 20 cm (basal), 50 cm (lower), 120 cm (middle)
and 180 cm (upper). Altogether, 80 quadrats in the tourism area
in the undisturbed area were investigated.
Four quadrats, each 400 cm2 (20 cm×20 cm, composed
of 400 grids, each 1 cm×1 cm), were made on each tree trunk
with thick bryophyte coverage. At each quadrat, the coverage
(the ratio of occupied grids to the total number of grids) of each
bryophyte was surveyed. All the bryophytes were collected
after investigation. All samples were dried at 60 ℃ for 24 h to
determine dry weight. Biomass was calculated in square meters.
Frequency index (%) was calculated as the ratio of quadrat
number with the bryophyte to the total number of the investigated
quadrats .
1.4 Data analysis
To test the difference in species composition between
tourism area and undisturbed area at the four tree-heights,
important value (IV) of each species was calculated. The IV
is an integrated index and is commonly used to characterize
species dominance in a community. Relative coverage (RC) is
the coverage of a species as a percentage of total plant coverage.
Relative frequency (RF) is the frequency of one species as a
percentage of total plant frequency. Relative biomass (RB) is the
biomass of one species as a percentage of total plant biomass. The
important value is calculated as: IV=1/3 (RC+RF+RB).
The number of species in the two areas was calculated.
Independent-samples t test (P＜0.05) was used to test the
difference in bryophytes (richness, coverage and biomass) at
the four different heights (20 cm, 50 cm, 120 cm and 180 cm)
between the two areas. All statistical analyses were carried out
with SPSS 9.0.
2 Results
2.1 Comparison of species composition
Nine species of bryophytes (including 8 mosses and 1
liverwort) were found in the two areas, and bryophytes occurred
slightly more abundant in the undisturbed area than in tourism
area (Table 2). Two species (Neckera pennata and Thuidium
cymbifolium) were found commonly in the both areas. Four
species, Leucodon sinensis, Leucodon secundus, Metzgeria
pubescens and Sphaerotheciella sphaerocarpa, occurred only
in the undisturbed area, and three, Brachythecium plumosum,
Camptothecium lutescens and Dlagiomnium rostratum only in
the tourism area (Table 3).
Species important values were signif icantly different
(Table 3). The most dominant bryophyte was N. pennata, and
its important value was significantly higher in the undisturbed
area (IV =0.7) than in tourism area (IV=0.56). In the tourism
area, three species (B. plumosum, C. lutescens and D. rostratum)
occurred at lower heights of tree trunk (20 cm and 50 cm), but
They were absent at higher heights (120 cm and 180 cm). While
in the undisturbed area, L. sinensis occurred more at lower height
(50 cm) because of its higher important value (IV = 0.23) than
at other heights. L. secundus and S. sphaerocarpa were found
at upper height with higher important value (IV = 0.03). M.
pubescens occurred most abundantly at tree basal height. Species
composition and distribution differed among the tree heights in
the two areas.
2.2 Composition of bryophytes richness, coverage
and biomass
Parametric analysis coverage, richness and biomass of
bryophyte community suggested that the epiphytic bryophytes
growing on A. faxoniana t runks were greatly affected by
tourism disturbance. The mean coverage in the two areas was
significantly different across all four heights (Fig. 2-A). The
mean coverage in the undisturbed area was signifi cantly higher
than that in the tourism area at all four heights. In the tourism
area, the mean coverage had the highest value at tree base, but
the lowest at the height of 120 cm. The mean coverage decreased
initially and increased then along tree height gradients. However,
in the undisturbed area, the coverage did not show the above
trend. Independent-samples t test showed that the differences in
Table 1 DBH of the selected trees in two areas
Parameter No. of studied trees
Mean DBH
(d/cm)
Stand
error
Tourism area 20 127.44 10.12
Undisturbed area 20 122.14 9.31
Sig. (2-tailed) 0.71 > 0.05
Table 3 Dominant values of the species in the two areas
Species Important value
Tourism area Basal Lower Middle Upper Total
N. pennata 0.40 0.61 0.95 1.00 0.56
T. cymbifolium 0.51 0.35 0.05 － 0.4
B. plumosum 0.07 0.04 － － 0.04
C. lutescens 0.01 － － － －
P. rostratum 0.01 － － － －
Undisturbed area
N. pennata 0.73 0.74 0.61 0.71 0.7
T. cymbifolium 0.17 0.02 0.16 － 0.11
L. sinensis 0.06 0.23 0.14 0.17 0.13
L. secundus － － 0.06 0.10 0.04
S. sphaerocarpa － － － 0.03 0.01
M. pubescens 0.04 － 0.03 － 0.01
Table 2 Species richness of bryophytes in the two areas
Area Moss Liverwort Total bryophytes
Tourism area 5 － 5
Undisturbed area 5 1 6
Two areas 8 1 9
472 15 卷应 用 与 环 境 生 物 学 报 Chin J Appl Environ Biol
bryophyte coverage were evidently signifi cant at the height 120
cm and 180 cm (sig. 2-tailed<0.01), that 50 cm was significant
(0.05>sig. 2-tailed>0.01) and that at tree base was not signifi cant
(sig. 2-tailed>0.05).
The richness index in the two areas was significantly
different among the four heights (Fig. 2-B). The mean richness
in the undisturbed area was significantly higher than that in
the tourism area at all four heights. In the disturbed area, the
mean richness had the highest value at tree base, and the lowest
at the height of 120 cm. The mean richness decreased initially
and increased then along tree height gradient. However, in the
undisturbed area, the richness showed no signifi cant relationship
with tree-height gradient. Independent-samples t test showed
that the evident difference in species richness of bryophytes
occurred at 120 cm and 180 cm heights (sig. 2-tailed<0.01), and
there was no difference found at the other two lower heights (sig.
2-tailed>0.05) of tree trunk.
The biomass in the two areas was significantly different
among the four heights (Fig. 2-C). The mean biomass in the
undisturbed area was signifi cantly higher than that in the tourism
area at all four heights. In the tourism area, the mean biomass
had the highest value at tree base and the lowest at height of 120
cm. The mean biomass decreased initially and increased then
along tree height gradient. However, in the undisturbed area,
the biomass showed no signifi cant relationship with tree-height
gradient. The independent-samples t test showed that differences
were evidently signifi cant at 50 cm, 120 cm and 180 cm (sig.2-
tailed<0.01), but no difference was found at tree basal height
(sig.2-tailed>0.05).
In conclusion, the coverage, richness and biomass of
bryophyte community on host tree trunks showed the decreasing
tendency of signifi cance increasing of tree height gradient in the
tourism area. At the height of 120 cm, species coverage, richness
and biomass declined to the minimum in the tourism area, but no
consistent trend was found in the undisturbed area.
3 Discussion
Tourism disturbance affected the epiphytic bryophytes
growing on A. faxoniana trees in the primary forests in the
Jiuzhaigou. This result showed that the microhabitat changes
related to tourism disturbance were important in determining
species composition. Though the distribution of epiphytic
bryophytes had no direct linkage with tourism disturbance, it
was significantly affected by this disturbance. N. pennata is a
rare species that is generally found in forest habitat and seems to
prefer diffusing light rather than direct light [21, 22]. This species
is more sensitive to environmental changes, and it was widely
found in both the two areas, but its population decreased in the
tourism area (Table 3). Another population, T. cymbifolium,
expanded in the tourism area because it is a widespread and
xeric-tolerant species that often grows on exposed soils and rocks
[23]. Our results showed hygrophilous species disappeared partly,
while disturbance-resistant and exotic species expanded their
populations in the tourism area. Therefore, it was suggested that
the tourism activities seriously affected not only the bryophytes
on ground and many other vascular plants [12], but also the species
composition of epiphytic bryophyte.
Tree base exhibited the highest bryophyte coverage and
the largest richness of species. The structure of bryophytes
was complicated in the undisturbed area (Fig. 2). The moisture
conditions in microhabitat seem strongly related to tree height
gradient, especially in drier places [24, 25]. Moisture decreased
from tree base to top in drier habitats. In the disturbed area,
tree base was found with the highest coverage, richness and
biomass, but the simplest structure on tree at the height of 120
cm. This result indicated that relatively wet climate was closely
related to the more complicated structure in the undisturbed
area and at lower heights on tree trunk. But in the undisturbed
area, this trend was not significant, implying that more stable
microenvironment across host tree height gradients. This
might be related to homogeneity in the moisture conditions
produced by closed canopy [25]. Therefore, we deemed that
environment quality degradation (eg. less humidity and more
sunlight) resulted from tourism disturbance is responsible for
simple epiphytic bryophyte community on the host trees in the
tourism area. Above this height, epiphytic bryophytes were more
susceptible to disturbance. Previous work showed that the ground
vascular plants were more susceptible to direct disturbance [1].
It was suggested that the mechanism of tourism disturbance on
community and biodiversity of epiphytic bryophytes differed
from ground plants and the indirect impact of the disturbance on
epiphytes was not equal along tree-height gradient.
Fig. 2 The coverage (A), richness (B) and biomass (C) of epiphytic bryophytes along tree height gradients in the tourism area and undisturbed area
The letters, B, L, M and U, represent the four heights, that is, 20 cm, 50 cm, 120 cm and 180 cm, respectively
4734 期 YAN Xiaoli, et al.：Effect of Tourism on Epiphytic Bryophyte Community Growing on Abies faxoniana Trees...
The impact mechanism that tourism disturbance directly
and immediately affects vegetation has been recognized widely.
Current studies of indirect disturbance on vegetation focused
less on epiphytic plants, nor quantified impacts at different
tree heights. Many native species were affected by competing
for resources including temperature, moisture and light. For
epiphytic bryophytes, tourism disturbance was a complex and
indirect threatening process which includes changes in light,
moisture and temperature associated with the coverage of upper,
middle and understory layers. Our study preliminarily reveals
that the tourism disturbance affects the population of epiphytic
bryophytes, and especially the bryophytes at higher heights
of tree trunk (120 cm and 180 cm). How tourism disturbance
affects epiphytic bryophytes at different trunk aspects and the
disturbance mechanism needs further research.
4 Conclusions
Tourism disturbance in the Jiuzhaigou World Nature
Her itage site changed species composit ion of epiphytic
bryophytes and decreased their richness, coverage and biomass.
Due to lack of root system and dependence on air humidity,
epiphytic bryophytes grow slowly. There are many measures
mentioned to conserve epiphyte diversity in agriculture landscape
or managed forests such as avoiding unnecessary damage of trees
and saving large trees [1]. The Jiuzhaigou World Nature Heritage
site, disturbed by a large number of tourists, should be required
to limit the number of tourists and regulate tourists’ behaviors to
protect epiphytic bryophytes there.
Acknowledgements We would like to thank the Jiuzhaigou
Administration Bureau for help in fi eld investigation.
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