KẾT HỢP KIẾN THỨC SINH THÁI BẢN ĐỊA VÀ ĐIỀU TRA RỪNG ĐỂ LỰA CHỌN LOÀI CÂY CHỈ THỊ NHẰM PHỤC VỤ CÔNG TÁC GIÁM SÁT TRẠNG THÁI RỪNG TẠI MIỀN TRUNG VIỆT NAM In tropical central Viet Nam, as part of a forest allocation program, forest condition should be monitored by local stakeholders. If local ecological knowledge can be integrated into the development of indicator species, then improvements in both the rigor of the indicator list and the involvement of local people in the monitoring process may occur. We used a dual methodology to derive two forest condition indicator species lists using trees, based on local ecological knowledge and quantitative forest surveys. Combining these lists allowed us to produce a final list of thirteen ‘probable’ and eight ‘possible’ indicator tree species for forest
Trang 1Short communication
Combining local ecological knowledge and quantitative
forest surveys to select indicator species for forest
condition monitoring in central Viet Nam
Ngo Tri Dunga,b,* , Edward L Webba
aNatural Resources Management, School of Environment, Resources, and Development, Asian Institute of Technology,
P.O Box 4, Klong Luang, Pathumthani 12120, Thailand
bFaculty of Forestry, Hue University of Agriculture and Forestry, 102 Phung Hung Street, Hue City, Viet Nam
1 Introduction
Ecologists and conservation practitioners have increasingly
utilized indicators species for environmental monitoring and
assessment (McGeoch, 1998; Kati, 2003) Plant species can be
used as indicators because they are easily sampled and stored,
taxonomically well known, and distributed over range of
habitats or environments (Faith and Walker, 1996) However,
development of indicator species usually employs intensive
survey methods that require well-developed researcher
qualifications (Dufreˆne and Legendre, 1997), and has often not integrated local ecological knowledge into the indicator set (Salam et al., 2006) Thus, the application of the indicators at the local level remains limited, particularly in rural settings of developing countries
In Nam Dong district of Thua Thien Hue province, central Viet Nam, the local authorities have allocated natural forests
to local people for long-term management since 2001 Because allocated forests are heterogeneous in levels of disturbance and stages of ecological recovery (‘condition’), they should be
a r t i c l e i n f o
Article history:
Received 4 December 2006
Received in revised form
3 September 2007
Accepted 18 September 2007
Keywords:
Degradation
Disturbance
Participation
Regeneration
Succession
Tropical forest
Tree community
a b s t r a c t
In tropical central Viet Nam, as part of a forest allocation program, forest condition should
be monitored by local stakeholders If local ecological knowledge can be integrated into the development of indicator species, then improvements in both the rigor of the indicator list and the involvement of local people in the monitoring process may occur We used a dual methodology to derive two forest condition indicator species lists using trees, based on local ecological knowledge and quantitative forest surveys Combining these lists allowed us to produce a final list of thirteen ‘probable’ and eight ‘possible’ indicator tree species for forest condition monitoring Despite some possible limitations to the methodology, we encourage the use of multiple data sets when working with rural communities that are involved in the monitoring process Local people can propose timely and appropriate measures of forest conservation and improvement, and can definitely integrate indicator species into mon-itoring community forests
#2007 Elsevier Ltd All rights reserved
* Corresponding author at: Natural Resources Management, School of Environment, Resources, and Development, Asian Institute of Technology, P.O Box 4, Klong Luang, Pathumthani 12120, Thailand Tel.: +84 54 529137; fax: +84 54 524923
E-mail address:dzungtringo@gmail.com(N.T Dung)
a v a i l a b l e a t w w w s c i e n c e d i r e c t c o m
j o u r n a l h o m e p a g e : w w w e l s e v i e r c o m / l o c a t e / e c o l i n d
1470-160X/$ – see front matter # 2007 Elsevier Ltd All rights reserved
doi:10.1016/j.ecolind.2007.09.002
Trang 2monitored regularly to collect information for appropriate
management practices Developing a list of indicator species
based on local ecological knowledge and quantitative
vegeta-tion plot data could contribute to long-term forest monitoring
since these two sources of information help to increase the
statistical rigour of those indicators This would also improve
levels of interest and confidence of local people when
monitoring forests that are under local community control
In this study we combined local ecological knowledge with
quantitative vegetation data to propose a set of forest
condition indicator species of trees for tropical forest in
Nam Dong district, Viet Nam
Nam Dong district is located in southwestern Thua Thien Hue
province in central Viet Nam The district ranges in elevation
from 300 m to 1700 m above sea level, and approximately 65%
of the district is covered with seasonal evergreen broadleaf
forest (Tordoff et al., 2003) Three communes selected for this
study were Thuong Quang, Thuong Long, and Huong Son
Major livelihood activities were paddy agriculture, swidden
agriculture, non-timber forest product (NTFP) collection and
small wildlife hunting Based on a combination of the
government forest classification system and local
descrip-tions, we classified forests into three groups Relatively intact forest (RIF) had a closed canopy, well-defined stratification, and the majority of large trees with a stem diameter greater than 20 cm Selectively logged forest (SLF) had been logged and exhibited a significantly altered structure from RIF Swidden forest (SWF) had regenerated after swidden agriculture or clear cutting since a logging ban was implemented in 1995 Most of the allocated forests have been RIF and SLF, with small areas of SWF allocated for plantation or upland crop cultivation (cassava, maize, and upland rice)
In order to develop a list of indicator species for these three forest types, we collected complementary sets of qualitative and quantitative data Qualitative data were obtained through village meetings and questionnaire interviewing of 118 experienced local people (woodsmen) Species were ranked for each forest type according to respondent value (ResVal), which was the percent of respondents listing that species as being exclusively or nearly exclusively found in one of the three forest types (i.e., an indicator)
Quantitative data were collected from 110 circular plots established across the three forest types, across the three study communes Each plot had a radius of 10 m and was placed randomly We did not survey woody seedlings or climbers because they were not comparable to the locally derived indicator list, which focused on life forms larger than seedlings Taxonomy followedHo (2000)and the Plant Name
Table 1 – Probable and possible indicator species for relatively intact forest (RIF), selectively logged forest (SLF), and Swidden forest (SWF) in Nam Dong district of Central Viet Nam
knowledge
Plot data
Probable indicator species
RIF Hopea pierrei DIPTEROCARPACEAE L-tree 69.5 1 25.0 10
Gironniera subaequalis ULMACEAE M-tree 22.9 7 49.4 1 Palaquium annamense SAPOTACEAE L-tree 17.8 9 43.9 2 Syzygium sp MYRTACEAE S-tree 21.2 8 39.4 3 Rhapis laosensis ARECACEAE Palm 28.8 6 11.7 21 Madhuca pasquieri SAPOTACEAE L-tree 13.6 10 28.0 7 SLF Horsfieldia amygdalina MYRISTICACEAE L-tree 18.6 1 38.5 7
Gardenia annamensis RUBIACEAE S-tree 15.3 3 35.9 8 Garcinia cochinchinensis CLUSIACEAE M-tree 10.2 6 26.2 16 SWF Mallotus paniculatus EUPHORBIACEAE M-tree 59.3 2 77.8 1
Macaranga denticulata EUPHORBIACEAE S-tree 16.9 7 70.2 2 Thysanolaena maxima POACEAE Grass 67.8 1 22.2 6 Melastoma candidum MELASTOMATACEAE Shrub 38.1 4 28.4 4 Possible indicator species
RIF Erythrophleum fordii CAESALPINIACEAE L-tree 45.8 2 – –
Parashorea stellata DIPTEROCARPACEAE L-tree 42.4 3 – – SLF Scaphium lychnophorum STERCULIACEAE M-tree – – 61.2 1
Knema pierrei MYRISTICACEAE L-tree – – 54.4 2 Croton cascarilloides EUPHORBIACEAE Shrub – – 50.6 3 Ampelocalamus patellaris POACEAE Bamboo 16.1 2 – –
Imperata cylindrica POACEAE Grass 52.5 3 – – Respondent values (ResVal) and indicator values (IndVal) were listed from local interview data and plot survey data, respectively L-tree: large tree (>30 m high); M-tree: medium tree (15–30 m high); S-tree: small tree (<15 m high)
Trang 3Index of Viet Nam (IEBR and CRES, 2003) From plot data, the
indicator value (IndVal) of each species was calculated using
the method of Dufreˆne and Legendre (1997) This method
combined information on the concentration of species
abundance in a particular forest type (specificity) and the
faithfulness of occurrence of a species in a particular forest
type (fidelity) The IndVal may range from zero (no indication)
to 100 (perfect indication) PC-ORD software (version 4.41,
McCune and Mefford, 1999) was used to calculate the IndVal
for each species
We constructed two final lists of indicator species based on
(1) the overlap between interview-derived and plot-derived
data for each species, and (2) the rank of that species in each
data type A ‘probable indicator species’ was one that
appeared in both sources of data for that forest type and
had high IndVal or ResVal for at least one data set A ‘possible
indicator species’ appeared in only one source of data but had
an IndVal or ResVal rank in the top three for that forest type
Thirty-two species were identified by local people as
indica-tors, with 15 for RIF, 9 for SLF, and 8 for SWF The top locally
known indicator species for RIF were Hopea pierrei,
Erythroph-leum fordii, and Parashorea stellata Local indicators for SLF were
Horsfieldia amygdalina, Ampelocalamus patellaris, and Gardenia
annamensis Top local indicator species for SWF were
Thysa-nolaena maxima, Mallotus paniculatus and Imperata cylindrica
Analysis of plot data yielded 21 indicator species for RIF, 30
for SLF and 15 for SWF The top plot-derived indicators for RIF
were Gironniera subaequalis and Palaquium annamense Top
indicator species for SLF were Scaphium lychnophorum, Knema
pierrei and Croton cascarilloides In SWF, indicator species were
M paniculatus, Macaranga denticulata and Sclera levis
Comparing the interview data with the plot data returned
13 probable indicators and eight possible indicators (Table 1)
H pierrei, G subaequalis, and P annamense appeared to be the
strongest probable indicators for RIF because they had both
high ResVals and high IndVals Probable indicator species for
SLF included H amygdalina, G annamensis, and Garcinia
cochinchinensis SWF probable indicators were M paniculatus,
M denticulata, T maxima, and Melastoma candidum Seven
species were possible indicators across the three forest types
including E fordii (RIF), S lychnophorum, K pierrei, C
cascar-illoides and A patellaris (SLF) Two possible indicator species for
SWF were Scleria levis and I cylindrica
There are two indicandum for which indicator species can be
used in monitoring levels of forest condition First, early
warning of forest degradation can occur over time if the
abundance of SWF or SLF indicators increases while the
abundance of RIF indicators declines In contrast, recovery of
degraded forest can be interpreted over time if the abundance
of RIF indicators increases and the abundance of SWF or SLF
indicators decreases While a wide range of species may
regenerate (establish) across forest types owing to dispersal
(e.g M denticulata in RIF, G subaequalis in SLF), when data are aggregated across a sufficient sample size and collected repeatedly over time, significant changes in frequencies of indicator species should indicate changing overall forest conditions This could be even more powerful if individuals
of indicator species are tagged and monitored to calculate survival and size class transition rates Seedlings and saplings could be included in the data set if favorable conditions for their growth are known
Various factors could influence the amount of overlap or mismatch between locally derived and plot-derived indicator lists First, some species listed by local people as important indicators for a particular forest type may be ecologically transient and present only for a short period of time, and thus rarely encountered in quantitative plots Examples in this study were Crassocephalum crepidioides and Eupatorium odor-atum (both local SWF indicators) Second, humans may alter the populations of potential indicator species, such that present and future capacity of that species to indicate trends
in forest condition is compromised E fordii and P stellata are large, commercially valuable timber species that were listed as indicators by local people, but had been heavily logged in the study area and were nearly absent from quantitative plots Third, local use of a species may influence people’s listing of it
as an indicator, with more valuable or commonly utilized species attaining higher prominence than more ecologically responsive species, in local observations of abundance in the forest These three factors may have affected the amount of agreement in locally derived and plot-derived indicator species lists
The results of this study suggest that indicator species may represent a cost-effective method for monitoring
by local people Care must be taken when interpreting reasons for mismatching of indicator lists Despite possible sources of confusion and imprecision, we encourage the use of multiple data sets when working with rural comm-unities that are involved in the monitoring process Local people can propose timely and appropriate measures of forest conservation and improvement, and can definitely integrate indicator species into community forest monitor-ing activities
Acknowledgements
We thank Tran Nam Thang, Ho Dinh Tuan, and Tran The Nhan
at the Faculty of Forestry, Hue University of Agriculture and Forestry for their contribution in collecting data and discus-sion This study was supported by a grant from the John D and Catherine T MacArthur Foundation to the Asian Institute of Technology
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