Journal of Sustainable Forestry
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Phytosociological Characteristics and Diversity of Trees in a Co-Managed Protected Area of Bangladesh: Implications for Conservation Tapan Kumar Nath, Mohammed Jashimuddin, Md Kamruzzaman, Vaskar Mazumder, Md. Kamrul Hasan, Sukumar Das & Panchannon Kumar Dhali To cite this article: Tapan Kumar Nath, Mohammed Jashimuddin, Md Kamruzzaman, Vaskar Mazumder, Md. Kamrul Hasan, Sukumar Das & Panchannon Kumar Dhali (2016): Phytosociological Characteristics and Diversity of Trees in a Co-Managed Protected Area of Bangladesh: Implications for Conservation, Journal of Sustainable Forestry To link to this article: http://dx.doi.org/10.1080/10549811.2016.1231615
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Date: 08 September 2016, At: 06:05
Phytosociological characteristics and diversity of trees in a co-managed protected area of Bangladesh: Implications for conservation
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TAPAN KUMAR NATH1†, MOHAMMED JASHIMUDDIN2, MD. KAMRUZZAMAN2, VASKAR MAZUMDER2, MD. KAMRUL HASAN2, SUKUMAR DAS3 and PANCHANNON KUMAR DHALI4
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1. School of Biosciences, University of Nottingham Malaysia Campus, Selangor, Malaysia
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2. Institute of Forestry and Environmental Sciences, University of Chittagong, Bangladesh 3. Divisional officer (retired), Bangladesh Forest Research Institute, Chittagong
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4. German Development Cooperation, Bangladesh
† Corresponding author, e-mail:
[email protected]
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ABSTRACT
The Chunati wildlife sanctuary (CWS), a degraded protected area in south-eastern Bangladesh,
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had been under co-management since 2004. This study examined phytosociological
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characteristics and diversity of trees in CWS and discussed villagers’ opinion on the impact of co-management on forest conservation. Following a stratified and systematic sampling 140 circular plots, 17.84m radius each, were laid out in seven forest beats for the assessment of phytosociological characteristics and tree diversity. Several key-informant interviews and 15
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focus group discussions were held to explore the impact of co-management on forest conservation and on villagers’ livelihood. A total of 93 tree species were identified having a diameter at breast height (dbh) of ≥5cm in 36 plant families. The dominant species were Acacia auriculiformis, Dipterocarpus turbinatus, Ficus hispida and Tectona grandis. The average density of trees was 239 trees/ha of which 60% was composed of planted exotic species. Nearly 90%
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trees were belonging to 5-15 cm dbh class and the Shannon-Wiener index was 3.15. The comanagement governance had brought positive changes in forest conservation. However, to sustain the engagement of poor villagers in the co-management and conservation of degraded
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CWS more collective efforts are needed to support their living.
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KEYWORDS. Diversity index, tree density, basal area, co-management, livelihood, forest
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conservation.
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INTRODUCTION
Forests of Bangladesh have been under serious threats from many factors including continuous
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illegal logging, deforestation, encroachment and expansion of mono plantations of exotic species which has caused the loss of rich biodiversity. Historically the forests were exploited to earn
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revenue and supply raw materials for the ship and rail industries during the British colonial era (1757-1947), and generate revenue and supply raw materials for forest industries during the
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period of Pakistan’s rule (1947-1971), which also continued into the current period of independent Bangladesh sovereignty (Iftekhar, 2006). Because of an inability to prevent widespread overexploitation of forest resources, many state forest areas have been rapidly
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degraded under population pressure and increasing demands for forest products (Biswas & Choudhury, 2007). According to Bangladesh forest department the country has now only 2.52 Mha, 17% of country’s total land, designated as forests (Choudhury & Hossain, 2011), although FAO (2011) estimated 1.44 Mha (11%) as effective forest cover. In order to arrest the forest loss and conserve
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biodiversity, the government of Bangladesh had declared patches of forests as protected areas under the provision of the Forest Act 1927, and the Bangladesh Wildlife (Preservation) Order 1973 (amended in 1974) . Since 1960s, a number of protected areas had been declared in the
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country. Protected area (PA) here refers to those forest protected areas designated as national parks, game reserves, wildlife sanctuaries, safari parks or eco-parks under the statute (DeCosse et
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al., 2012a). Most declared PAs have been carved out of existing reserve forest land, and continue
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to have borders with existing reserve forests (DeCosse et al., 2012b). However, simple declaration of PAs has not functionally worked in the prevention of loss of biodiversity because
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local communities are put to hardships after notification of a forest as PA mainly due to the curtailment of the flow of forest resources for their livelihoods through strict regulation
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(Chowdhury & Koike, 2010). Historically, protected areas in Bangladesh have been managed using approaches that exclude local people, whose interests have been viewed as incompatible
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with the conservation of protected areas (Sarker & Roskaft, 2011).
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In 2004, with funding from the US Agency for International Development (USAID), the Nishorgo Support Project (NSP) initiated a pilot project “Co-management of PA” in five PAs with the active participation of local communities (Chowdhury & Koike, 2010; Sarker & Roskaft, 2011; DeCosse et al., 2012b). In 2008, the forest department (FD) and USAID extended
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co-management in 17 PAs and in one eco-park through integrated protected area co-management (IPAC) project with the aim of improving local peoples’ livelihoods through greater access to and control over local forest resources (Begum, 2011). The Chunati Wildlife Sanctuary (CWS) represents a fragile forest landscape in the country’s south-eastern region (Figure 1) which had been brought under co-management of PA since 2004 in order to initiate and implement a
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sustainable co-management approach for biodiversity conservation. Since then, a number of donor funded development projects have been implemented to continue the co-management activities in the CWS.
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In order to facilitate the creation and implementation of more effective conservation measures
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for sustainable management of tropical forests an understanding of phytosociological characteristics of existing vegetation (in terms of floristic structure, composition, associations,
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dominance) and, their diversity and regeneration is essential (Biswas & Misbahuzzaman, 2008; Tripathi & Tripathi, 2010; Htun et al., 2011; Kushwaha & Nandy, 2012; Feroz et al., 2014). In
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case of CWS there have been limited studies that examined the phytosociological characteristics of trees. Moreover, the CWS had been under co-management since 2004 but the impact on forest
To assess the composition, structure, and diversity of trees, and natural regeneration in
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the CWS, and
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•
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conservation is still not well-documented. Considering these shortcomings this study aimed at:
To elucidate villagers’ opinion on the impact of co-management on forest conservation.
It was expected that findings of the study would help to recommend important policy
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implications for the sustainability of co-management and the CWS.
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MATERIALS AND METHODS Data collection for this research was conducted through vegetation survey, key-informants
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interview and focus group discussion, and carried out between July to December 2011.
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Key-informants Interviews and Focus Group Discussion
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Key-informant interviews were conducted with FD staff members including forest rangers, beat officers and guards, and sought their opinions on the co-management approach and its impact on
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forest management. A total of 15 focus group discussions, eight with community patrol groups (CPG) members, three with village conservation forums (VCF) members, three with local people
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(who are not CPG or VCF members) and one with co-management committee (CMC) members were held. Group discussions highlighted villagers’ opinion on impact of co-management on
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forest conservation, their involvement on forest conservation and enhancement of livelihoods
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due to co-management. A checklist was used to facilitate the discussion.
Forest Vegetation Survey
For the vegetation survey, stratified and systematic sampling was followed. The CWS consists of
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seven forest beats and each of them was treated as a strata. In total 140 circular plots (17.84 m radius), 20 in each beat were laid out. Circular plots are commonly used in vegetation studies, easy to establish, minimize error due to edge effects, provide relatively accurate and time efficient results on small stems (Sparks et al., 2002; Gage & Cooper, 2010). For locating plots, a base map of every beat was copied on tracing paper, with a point on each map near a permanent
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feature selected. Four or five equidistant parallel lines were then drawn on each map and 20 equidistant plots were marked on the lines. After identifying the point physically on ground, the first plot on the first line was selected by using a compass and a GPS (global positioning system)
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device (Garmin - GPSmap76Cx). The coordinates of the center points of each plot were recorded. Distance from plot to plot and line to line was measured based on base map scale and
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then located using the GPS. By using Google Earth Map the coordinates of all plots were laid out
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on respective beats of the CWS (Figure 1). For the regeneration study 140 co-centric plots, each with 1.25 m radius were laid out in seven beats.
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A field data collection format consisting of name of forest range and beat, geographical coordinates, tree species name, diameter at breast height (dbh), number of recently felled stumps,
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name and number of each regenerating tree species was used. All trees having dbh at least 5cm in each plot were counted species wise and the dbh were recorded. The number of recently felled
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stumps was counted. For regeneration, the numbers of seedlings (up to 1m in height) and
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saplings (1-2.5m in height) were counted for each species. Common tree species were identified directly in the field with help from local people and forest department staff. For unidentified tree species, plant parts (twigs, flowers and fruits) were collected and preserved in a herbarium, and later identified by a plant taxonomist in the Department of Botany, University of Chittagong,
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Bangladesh.
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Data Processing and Analysis The phytosociological characteristics of tress including the species density, relative density
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(RD), frequency, relative frequency (RF), relative dominance (RDo), abundance, relative abundance (RA) and importance value index (IVI) of each species were calculated using
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formulae given by Moore & Chapman (1986). The IVI for regeneration was calculated as sum of RD, RF and RA whereas IVI for tree species was the sum of RD, RF and RDo. Several diversity
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dominance, and Disturbance index) were determined.
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indices (including Shannon-Wiener’s diversity index, Evenness index, Richness index, Index of
H= -∑ (ni/N) x Ln (ni/N)
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The Shannon-Weiner diversity index (H) was calculated according to Shannon & Weiner (1963):
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where ni= Number of individuals of one species in a site
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N= total number of individuals of all species in a site The Indices of species richness (R) and evenness (E) were estimated using the formula of Margalef (1958) as cited by Kohli et al. (1996):
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R= (S-1)/LnN E= H/LnS where
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S= total number of species; N= the individuals of all the species, and
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H = the Shannon-Weiner Index of Diversity.
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The Index of dominance (ID) was measured by Simpson’s Index (Simpson 1949):
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s ID = ∑(ni/N)2
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i=1
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S= the number of species
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where ni= the number of individuals of each species
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N= total number of individuals of all species
The disturbance index was estimated using following formula given by Tripathi & Tripathi (2010):
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Disturbance index = (Number of tree stumps / Total number of trees including tree stumps) × 100
Tree basal area was calculated following Chaturvedi & Khanna (1982). In order to observe the variation over CWS landscape forest vegetation data were grouped into: whole CWS, range, beat and distance gradient from boundary towards interior of
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the forest. A one-way analysis of variance followed by Duncan multiple range test (DMRT) was conducted for some selected variables to observe the statistical differences among beats and distance gradients. Findings on phytosociological characteristics and diversity indices are
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explained quantitatively, and information from key-informants interviews and group discussions
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RESULTS AND DISCUSSION
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are analysed qualitatively.
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Villagers’ Knowledge on Past and Present Forest Condition In group discussions villagers reported that before declaring the Chunati reserve forest as the
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CWS in 1986, it was a very dense forest. They reported that there were an uncountable number of big trees, mostly of Dipterocarpus species. They said the forest canopy was so closed that
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even during daytime people could not see anything inside the forest. Many species of wildlife including elephants inhabited the area and people were afraid to enter into the forest. Villagers
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commented that just before declaring CWS local influential people started felling trees with passive support from dishonest forest officials. At the same time when the government promoted the green revolution with the slogan of “No land can be left vacant, cultivate rice and be self-
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dependent”, these influential people then occupied deforested land and converted into agricultural land. During this study villagers were observed to convert degraded forest land into betel leaf and sun-grass plots (shonkhola) for which, as villagers said, they had to pay bribe money to FD
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staff. Some influential villagers had established plantations mainly of Acacia species on degraded forest land of CWS. These plantations were well protected with fencing and trees were growing well and nobody cut trees from there. These villagers commented that they had to pay
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bribe money twice – at the time of planting and before harvesting – to FD staff.
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The FD established about 2000 ha of plantations including 334 ha of social forestry plantations from 2002 through 2011. The sanctuary had not been divided into core and buffer zones and
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hence it was unidentified in which zone social forestry and other plantations were established. The staff members reported that half of the plantations were composed of native species and the
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rest with exotic species mainly of Acacia auriculiformis. The reason for planting exotic species, as they mentioned, was that this species could survive in harsh condition and grow quickly, and
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with better growth performance of exotics they could show the performance of plantation program to higher officials. They also reported that native species require regular silvicultural
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management including weeding, watering at least 3 - 4 years after planting for which they did
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not have enough budget. The FD staff said that due to budget constraints they could not perform post-planting management and most of these plantations had been invaded by weeds.
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Phytosociological Characteristics of Tree Species The vegetation survey recorded 93 tree species, 65 in Chunati and 76 in Jaldi range, respectively belonging to 36 plant families in the CWS (Table 1). Among the plant families Euphorbiaceae (8 species) and Mimosaceae (8 species) contain the highest number of tree species followed by Myrtaceae (7 species), Lauraceae (5 species), Moraceae (5 species), Verbenaceae (5 species),
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Rubiaceae (5 species) and Tiliaceae (5 species) (Appendix 1). The number of tree species was found decreasing towards the interior of the CWS (Table 2). The dominant species in terms of IVI (Figure 2) in the whole CWS were Acacia auriculiformis
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(IVI=48) followed by Dipterocarpus turbinatus (27), Ficus hispida (24), Tectona grandis (21),
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Shorea robusta (13) and Acacia mangium (12). Among these species D. turbinatus and F.
hispida are native species. The IVI values indicate that the CSW forest was dominated by exotic
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species even though it is a wildlife sanctuary. These species produce no edible fruits or shoots for wildlife and due to lack of food wildlife most often enter into villages and damage
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agricultural produces. The villagers urged to plant more local fruits trees in the CWS areas so
produces.
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that wildlife would get abundant food in the forests and would not destroy villagers’ agricultural
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The above phytosociological attributes of CWS are comparable to similar forests in Bangladesh and neighboring countries. In an evergreen forest in north-eastern India, for example, Tripathi &
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Tripathi (2010) recorded 76 tree species from 1-ha of sample plot. Htun et al. (2011) identified 86 tree species in 1.68-ha sample area from Popa mountain park, Myanmar. In Bangladesh, Biswas & Misbahuzzaman (2008) recorded 66 tree species under 27 families from 2-ha sample
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plot of a sub-tropical reserve forest. In a wet evergreen forest of Chittagong, Bangladesh Feroz et al. (2014) identified 40 woody plant species. Sarker et al. (2015) recorded 78 tree species from 0.04ha sample plots from a natural forest in northeastern Bangladesh.
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Tree Stock, Structure and Diversity Indices The stock and structure of trees in the CWS included tree density, basal area and dbh class
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distribution. The average density of trees in the CWS was 239 trees/ha of which 60% was composed of planted exotic species including Acacia auriculiformis (26% individuals), Tectona
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grandis (10%), Eucalyptus camaldulensis (8%), Shorea robusta (5%) and Gmeilina arborea
(3%) and the remaining 40% stock (96 trees/ha) was composed of 86 species which were mostly
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indigenous trees. The dominant indigenous species were Ficus hispida (8% individuals), Trema
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orientalis (2%), Firmiana colorata (2%), Anogeissus acuminate (2%), and Terminalia belerica (2%). The tree density varied over the CWS landscape. Across forest beats (smallest forest
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administrative unit), Chunati had the highest tree density (498 trees/ha) which was significantly (PJaldi>Napura>Aziznagar>Herbang>Chunati. The similar trend
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was also observed for species richness index but it was significantly higher in Chambal than other forest beats. No significant difference was found for evenness index. The maximum
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evenness was for Chambal (1.87) and minimum for Chunati (1.33). The index of dominance of
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the CWS was 0.09 with minimum in Chambal (0.08) and maximum in Chunati (0.27). The Shannon-Wiener index was significantly higher (P
