Forest and vegetation of particular ecosystem is generally influenced by external factors especially from development activities. Nepal has been endowed with an immense variety of forest resources with its unique biodiversity. The current study is conducted in the temperate forest of central Nepal to compare the state of vegetation recorded during 1995 with the present condition. To identify floristic composition, species distribution and diversity, same location and same size of quadrates were selected in natural forest and planted or regenerated area as in previous study. Measurement and analytical tools for forest and vegetation reveled a total of 19 species and 341 individuals in 0.14 ha regenerated area and 18 species, 17 genera and 260 individuals in 0.16 ha, natural forest areas. However, in 1995, total 31 individuals of 20 woody species, 18 genera and 15 families were recorded within the sampling plots of 0.16 ha of natural forest. Moreover, Alnus nepalensis is found dominating regenerated area and Caryopteris odorata in natural forests whereas in 1995, Litsea chartacea and Maesa chisia were recorded dominant. The Shannon’s diversity H’ = 2.908, E = 0.970 and Var H’ = -0.00 and Simpsons D = 0.027 recorded in 1995 is found to be with higher values when compared with the analysis of present study. Furthermore, in comparison to 1995 study, this study showed lower basal area and timber volume with declining species diversity. Although, the natural forest is found with higher species composition compared to rehabilitated forest, species of herbs and shrubs were found extensively growing.
The forests of the world play vital role in maintaining and balancing natural eco-system. These forest resources fulfill human demands by providing renewable raw materials and energy, maintain biodiversity and protect land and water resources. These resources are under degradation extensively due to increasing population pressure, agricultural and urban expansion, industrialization, infrastructure development and other disturbances.
In global scenario, Nepal allows many habitats and tremendous biodiversity and ecosystems representing 29% of forest resources. It holds less than 0.03% of earth surface which blessed with 1.3% (22,000 species) species of plants and animals embracing 49th position in the Worlds Biodiversity Index [
According to Clements, 1916 [
The external environmental factors of disturbance suddenly change the composition of plant structures. The present vegetation composition of a particular ecosystem reflects the site conditions and disturbances over the time. To estimate environmental change at a given site with reference to different current vegetation comprising pristine or potential natural vegetation, a hemeroby concept was developed [
Furthermore, as the species number found depends on the plot size studied (i.e. species-area relationship); the method cannot be used for cross scale evaluation. According to Karki, 1991 [
Several global vegetation mapping systems use temperature and moisture relations as predictors for vegetation types occurring in different areas [
Humankind development activities entail a change in land use, biodiversity and habitats, running the risk of potential destruction, degradation and fragmentation of natural habitats. Potential repercussions that could occur during construction activities can have temporary or permanent negative impacts on biodiversity and habitats with different intensity, magnitude and size depending on location, ecosystem, location and site size. The potential impact is largely depending on specific habitat conditions, species and the level of awareness of the people surrounding the natural environment. To protect and restore forest resources an integrated assessment tool is necessary to support decision making towards human impacts on forest biodiversity and their use [
Government of Nepal has applied EIA since 1993 with formulation of Environmental Impact Assessment Guideline and formally after endorsement of Environmental Protection Act and its Regulation 1997. Accordingly, EIA study suggested implementation of mitigation measures for impact area of upper bhotekoshi hydropower project. The comparison of data since 1995 feasibility study, 1997 EIA study and EIA monitoring period from 1998-2002 to this study analyzed variation in species composition and distribution. The existing forests of the study areas fulfill daily demand of firewood, litter, fodder and timber to support the livelihoods of rural communities, but similar other activities face pressure like clearance for agriculture, browsing by livestock, human-set fires, timber logging, and fuel wood extraction. The temperate forest and vegetation of the study area comprised with lower temperate mixed broad-leaved forest, riverine forests with association of Tona, Albizzia and Bombax and upper temperate mixed broad-leaved forest (Quercus-Rhododendron-Tsuga forest). Later on the study site was selected for planned development activities in and around of the forest areas. Previous studies experiencing high rates of forest loss and degradation as a result of over-exploitation and conversion of forest to other land uses in many developing countries [
Development activities cause impacts in the ecological processes, both at the landscape scale and the scale of individual forest patches which influence species composition and habitat characteristics at different scales. Restoration of such disturbed ecosystem can be achieved through establishment of native tree species including artificial establishment and/or encouragement of natural regeneration, in a wide range of site conditions (Newton et al. 2009). These restoration practices of forests take a great deal of time to recover following disturbance. Whereas, total stem number, basal area, or leaf area index rapidly recover the structural characteristics and late- successional species composition or the number of large trees for variables characterizing old-growth conditions require a timescale of centuries to re-establish [
This study relates the impacts and changing pattern of forest and vegetation during the implementation and operation of the development activities. The collected ecological data in phased wise manner and different time period are valuable for reconstructing early environmental and vegetation community conditions and examination of changes towards vegetation communities and disturbance regimes. The data’s collected and experimentally calculated over decadal and longer temporal scales were free from error.
The study area lies between 27˚54'87"N latitude and 85˚55'51"E longitude along the Botekoshi River within the Tatopani and Phulpingkatti Villages Development Committees (VCDs) of Sindhupalchowlk district, Nepal (
The proposed study area Botekoshi River basin was described rich forest and vegetation except on steep slope east to Larcha, across the River (EIA study of Botekoshi hydropower project, IUCN 1995 [
The lower temperate mixed broad-leaved forest along the Bhotekoshi river basin recorded dominant evergreen laurels comprising species of Actinodaphne anguistifolia, Persea ghamblei, Litsea elongeta, Neolitsea spp, Cinnamomoum spp and Dodecadenia spp with other associated species in the forest species of Macarange, Leucosceptrum, Michillia spp, Acer, Dynplocos, Caryoteris and Measa sps. Along the Bairabkunda Khola, above Larcha comprised degraded riverine forests. This forest dominated by the species of Albiizzia, Bombex, Macarange and Alnus spp towards the lower part. As one ascends the Bairabkunda Khola, again the lower temperature mixed broad leaved forest with evergreen laurels were reported. Species of Wendlandia, Enelhardia, Michelia, Caryoptries and Measa were reported as major associate species in this forest. These characteristics features of forest and vegetation studied in pre and post periods of EIA surroundings of upper Bhotekoshi hydropower project area.
For this study, two types of forest, natural and planted or regenerated forest and vegetation (disturbed slopes by the projects) were selected. The natural forest comprises community forest determined as influence zone of the project in EIA study. The planted forests are the disturbed slope of the study area with adoption of the mitigation
measures. To enumerate and identify floristic composition, community sampling units were established. Quadrate, transect and point sampling methods were used with the size of 10 × 10 m2 for regeneration or planted area and 20 × 20 m2 for natural forest areas. Several blocks or squares (quadrates) with definite size were established in the natural and project disturbed area to identify total number of trees, shape and size as described by Mueller-Dombois and Ellenberg, 1974 [
Suunto Hypsometer was used for measuring height of the trees. Likewise, for measuring diameter and circumferences, instruments like Caliper, Finnish Caliper and measuring tape were employed. For McHarg overlays, Geographical Information Systems (GIS), GPS was used. The diameter was measured at 1.30 m aboveground. In case of normal trees, measurement was done horizontally and strait across the stem for leaning trees. Likewise for forking trees, forks above 1.30 m were taken into account as two trees.
The transect stands of an area of 100 m2 size (0.01 hectare), having 10 m length and breadth each, were fixed by measuring tape. Planted area was estimated dividing the reforested area in 10 ha blocks (200 × 500 m). Planted area less than 10 ha was divided in 1 ha block (100 m × 100 m). Similarly, in natural forests around at dame site, adit a, adit b, and powerhouse area, 20 × 20 m2 quadrate was established. Trees with girth exceeding 10 cm diameter at breast height (dbh, at 1.37 m above the ground) were measured. The height of standing trees was measured by means of clinometers. Finally, vegetation analysis was done by adopting releve analysis approach (M. Dombosis and Ellenberg, 1974). The plant species of all growth forms within each quadrate were enumerated by using a simple matrix. The diameter at breast height and height of each trees including cut stumps, having more than 10 cm circumference were measured by using measuring tape and calibrated 1 m long pole, respectively.
Density, frequency, basal area and their relative values of tree species were calculated following Mueller-Dombois and Ellenberg, 1974. Botanical name and author citation were written as per Department of Plant Resources 2000 [
The species area curve of each community forests was calculated by randomly adding up the number of tree species in each quadrate. “S”, or species richness, was determined following Whittaker, 1976 [
Simpson’s index “D” was calculated using the formula
where,
Shannon-Weiner’s diversity index “H” was calculated using the formula
where,
Hill diversity indices were calculated using the following formulae:
Number 0: N0 = S, where S is the total number of species
Number 1: N1 = eH, where “H” is the Shannon’s index (3)
Number 2: N2 = 1/D, where “D” is Simpson’s index
Composition and distribution pattern of vegetation and forest types and change of environmental gradients in the project area was studied with extensive literature [
where, V = Volume, BA = Basal Area (m2), h = Height (m).
Species area curve estimate
The plots of the studied area were examined estimating Species Area Curve with cumulative sampling area (x-axis) versus the total number of species found in the quadrate samplings (y-axis). The species area curve was used as a log-log relationship [
where; S = Number of species (= species richness); A = Area sampled; a = y-intercept of the regression.
The composition and distribution for plantation or regeneration area (disturbed slopes of the project area) are given below:
Total 8 quadrates of 10 × 10 m2 were established in the headwork area including above wire site, dam site, access road and Adit A. Similarly, 4 quadrates in Adit B and 2 quadrates of similar size at powerhouse site were selected. These areas were the disturbed slopes of construction stage which were rehabilitated as per mitigation measures after construction. Altogether, 14 quadrates of 10 × 10 m2 covering 0.14 ha area were studied representing total of 19 species, 15 genera, 13 families and 341 individuals (
In the study area, floristic composition and distribution comprises nearly 45 tree and shrubs representing 15 species belonging to 15 genera and 13 families. Among them, 4 new planted species were identified at powerhouse site. The under-storey vegetation below the girth limit of 10 cm revealed almost 86% of the total numbers of species confined in the forest while 14% represented abundance of shrubs species. The abundance of the species identified during the feasibility study in 1995 is quiet different as this study found single species of Alnus nepalensis (Bhatt, 2010 [
Location | No. of Quadrates Size (10 × 10 m2) | Total Species | Total Genera | Total Individuals | Total Area |
---|---|---|---|---|---|
Dam Site | 8 | 10 | 10 | 174 | 800 m2 (0.08 ha) |
Adit B | 4 | 2 | 2 | 142 | 400 m2 (0.04 ha) |
Powerhouse | 2 | 7 | 7 | 25 | 200 m2 (0.01 ha) |
Total | 14 | 19 (15) | 19 (15) | 341 | 1300 m2 (0.13 ha) |
SN | Scientific Name | Nepali Name | Family | Abundance of Species in Sampling Plots | Total | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | |||||
1 | Actinodaphne anguistifolia | Jhankri Kath | Lauraceae | - | - | - | - | + | - | - | - | - | - | - | - | - | - | 1 |
2 | Albizzia chinensis | Siris | Leguminosae | - | - | - | - | - | - | - | - | - | - | - | - | + | + | 2 |
3 | Alnus nepalensis | Utis | Betulaceae | + | + | + | + | + | + | + | + | + | + | + | + | + | - | 13 |
4 | Arundinaria falcata | Nigalo | Poaceae | - | - | - | + | + | - | - | - | - | - | - | - | - | - | 2 |
5 | Choerospondias axillaris | Lapsi | Anarcadaceae | - | - | - | - | - | - | - | - | - | - | - | - | - | + | 1 |
6 | Ficus nerrifolia | Nimaro | Moraceae | - | - | - | - | - | - | - | - | - | - | - | - | + | - | 1 |
7 | Fraxinus floribunda | Lakure | Oleaceaae | - | - | - | - | - | - | - | - | - | - | - | - | + | - | 1 |
8 | Golko Rukh | Uniden. | Rannanculaceae | - | + | + | - | - | - | - | - | - | - | - | - | - | - | 2 |
9 | Juglans regia | Okhar | Juglandaceae | - | - | - | - | + | - | - | - | - | - | - | - | - | - | 1 |
10 | Leucosceptrum canum | Dhursul | Labiateae | - | - | - | - | - | - | - | - | + | + | + | + | - | - | 4 |
11 | Litsea elongeta | Pahale | Lauraceae | - | - | - | - | + | - | - | - | - | - | - | - | - | - | 1 |
12 | Macaranga denticulata | Malato | Euphorbiceae | + | + | + | + | + | - | - | - | - | - | - | - | - | - | 5 |
13 | Maesa chisia | Bilaone | Myrsinaceae | + | + | + | + | + | + | - | + | - | - | - | - | - | + | 8 |
14 | Rhus javanica | Bhalayo | Anacardaceae | - | - | - | - | + | - | - | - | - | - | - | - | + | - | 2 |
15 | Toona ciliata | Tooni | Meliaceae | - | - | - | - | - | - | - | - | - | - | - | - | - | - | 1 |
Total | 3 | 4 | 4 | 4 | 10 | 2 | 1 | 3 | 2 | 2 | 2 | 2 | 5 | 3 | 45 |
Note: + = Presence, - = Absence.
The species-area curve, expressed mathematically, shows the increasing trend of species abundance to certain limits of constant followed by prediction effects with species survival rates (
Trees and shrub species in sampling plots were identified in 3 main sampling units, Dam site, Adit B and Powerhouse area with sampling plots of 8, 4 and 2 respectively. 174 individuals belonging to 10 species recorded in dam site with highest number (41.37%) of Alnus nepalensis in all plots. The individual tree species Maesa chisia (32.18%), and Macaranga denticulata (18.96%) followed with shrub species Arundinaria falcate (3.44%). Single individuals of each Actinodaphne anguistifolia, Litsea elongeta, Rhus javanica, Juglans regia and Toona ciliata represented the lowest (0.57%) number (
The species diversity of Simpsons Index (D) showed 3.243 suggesting higher diversity in the area of 1 ha. Likewise, Shannon-Weiner index of species diversity (H) was 1.963. However, the value exceeds the maximum value assumed for H (i.e. log S); it is not surprising since the forest area is highly diverse (
Total 79 individuals of trees belonging to 6 species and 6 genera were recorded in 10 sampling quadrates. The highest 13 individuals of Alnus nepalensis were recorded in plot number 7 with 3.12 m2 basal area and 18.53 m3 timber volume while the lowest number of individuals were recorded in plot number 2, 3, 4, and 5. The individuals with the highest basal area (31.27 m2) and timber volume (445.97 m3) is observed in plot 2 and the lowest basal area (0.29 m2) and timber volume (1.68 m3) was found in plot number 6 (
The study area comprises lower and upper temperate broad leaved and deciduous riverine forest. The main channel of Bhotekoshi River with its tributaries mixes in Jungkhola above dam site, Bhairabkunda khola below dam site and Khukundol khola near Adit B where sparse riverine forest exists. The natural forest represents following range of floristic composition and species distribution.
(a) Dam Site (Headwork Area) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
SN | Scientific Name | Nepali Name | Sampling Plots* | Total | |||||||
1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | ||||
1 | Alnus nepalensis | Utis | 9 | 7 | 9 | 7 | 2 | 12 | 13 | 13 | 72 |
2 | Macaranga denticulata | Malato | 6 | 16 | 4 | 4 | 3 | 0 | 0 | 0 | 33 |
3 | Maesa chisia | Bilaone | 4 | 2 | 10 | 25 | 5 | 6 | 0 | 4 | 56 |
4 | Unidentified spp | Golko rukh | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 2 |
5 | Arundinaria falcata | Nigalo | 0 | 0 | 0 | 1 | 5 | 0 | 0 | 0 | 6 |
6 | Actinodaphne anguistifolia | Jhankri kath | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 |
7 | Litsea elongeta | Pahale | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 |
8 | Rhus javanica | Bhalayo | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 |
9 | Juglans regia | Okhar | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 |
10 | Toona ciliata | Tooni | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 |
Total | 19 | 26 | 24 | 37 | 19 | 18 | 13 | 18 | 174 | ||
(b) Adit B (Between and within access road) | |||||||||||
1 | Alnus nepalenesis | Utis | 9 | 17 | 14 | 20 | - | - | - | - | 60 |
2 | Leucosceptrum canum | Dhursul | 10 | 25 | 12 | 35 | - | - | - | - | 82 |
Total | 19 | 42 | 26 | 55 | - | - | - | - | 142 | ||
(c) Powerhouse Area (Access road and Penstock area)# | |||||||||||
1 | Alnus nepalensis | Utis | 8 | 0 | - | - | - | - | - | - | 8 |
2 | Ficus nerrifolia | Nimaro | 1 | 0 | - | - | - | - | - | - | 1 |
3 | Fraxinus floribunda | Lakure | 1 | 0 | - | - | - | - | - | - | 1 |
4 | Rhus javanica | Bhalayo | 1 | 0 | - | - | - | - | - | - | 1 |
5 | Albizzia chinensis | Siris | 5 | 4 | - | - | - | - | - | - | 9 |
6 | Maesa chisia | Bilaone | 0 | 3 | - | - | - | - | - | - | 3 |
7 | Choerospondias axillaris | Lapsi | 0 | 2 | - | - | - | - | - | - | 2 |
Total | 16 | 9 | - | - | - | - | - | - | 25 |
Note: *Sampling Sites: Quadrate number 1 - 3 Adit A, 4 - 5 = Below Access road of Adit A, 6 = below dam site above access road, 7 - 8 = Dam site below Daskilo; #Quadrate number: 1 = Access road Powerhouse, 2 = Penstock area.
Species Diversity Index | Dam Site | Adit B | Powerhouse Site |
---|---|---|---|
Simpsons index (D) | 3.243 | 1.966 | 4.411 |
Shannon’s Diversity (H) | 1.963 | 0.982 | 2.272 |
Shannon’s Max (Hmax) | 3.321 | 1 | 2.807 |
Species equitability (E) | 0.591 | 0.981 | 0.809 |
Quadrate 1: Adit A | |||||||
---|---|---|---|---|---|---|---|
SN | Scientific Name | Numbers | Gbh (cm) | GBH (m) | Height (m) | BA (m2) | Volume (m3) |
1 | Alnus nepalensis | 8 | 15 - 40 | 0.1 5 - 0.4 | 7 - 9 | 0.45 | 1.86 |
2 | Macaranga denticulata | 2 | 30 - 40 | 0.3 - 0.4 | 9 - 10 | 0.2 | 0.95 |
Total | 0.64 | 2.81 | |||||
Quadrate 2: Adit A (Golko Rukh) | |||||||
1 | Alnus nepalensis | 2 | 30 - 65 | 0.3 - 65 | 5 - 10 | 0.4 | 1.83 |
2 | Unidentified spp (Golko rukh) | 1 | 6.2 | 6.2 | 29 | 30.18 | 437.54 |
3 | Macaranga denticulata | 2 | 60 - 72 | 0.6 - 0.72 | 15 - 22 | 0.69 | 6.6 |
Total | 31.27 | 445.97 | |||||
Quadrate 3: Adit A (Golko Rukh II) | |||||||
1 | Alnus nepalensis | 1 | 56 | 0.56 | 7 | 0.25 | 0.86 |
2 | Unidentified spp (Golko rukh) | 1 | 3.45 | 3.45 | 32 | 9.34 | 149.5 |
Total | 9.59 | 150.36 | |||||
Quadrate 4: Adit A (Access road edge of the river) | |||||||
1 | Unidentified spp (Golko rukh) | 4 | 15 - 1 | 0.8 - 1 | 9 - 25 | 2.01 | 21.06 |
Quadrate 5: Below Access Road | |||||||
1 | Juglans regia | 1 | 1.5 | 1.5 | 6 | 1.77 | 5.3 |
2 | Actinodaphne anguistifolia | 1 | 16 | 0.16 | 5 | 0.02 | 0.05 |
3 | Macaranga denticulata | 3 | 12 - 15 | 0.2 - 0.15 | 9 - 10 | 0.06 | 0.29 |
4 | Alnus nepalensis | 2 | 11 - 60 | 1.1 - 0.60 | 12 - 20 | 1.23 | 11.19 |
5 | Litsea elongeta | 1 | 65 | 0.65 | 6 | 0.33 | 0.99 |
Total | 3.41 | 17.52 | |||||
Quadrate 6: Below Dam site above access Road | |||||||
1 | Alnus nepalensis | 5 | 10 - 50 | 0.1 - 0.25 | 9 - 12 | 0.29 | 1.68 |
Quadrate 7: Along dam site | |||||||
1 | Alnus nepalensis | 13 | 36 - 72 | 0.36 - 0.72 | 7 - 14 | 3.12 | 18.53 |
Quadrate 8: Upstream Left-hand site dam site | |||||||
1 | Alnus nepalensis | 7 | 16 - 65 | 0.16 - 0.65 | 7 - 15 | 0.65 | 4.18 |
Quadrate 9: Audit B access road | |||||||
1 | Alnus nepalensis | 8 | 15 - 65 | 0.15 - 0.65 | 10 | 1.54 | 10.65 |
Quadrate 10: Audit B access road | |||||||
1 | Alnus nepalensis | 17 | 24 - 48 | 0.24 - 0.48 | 5 - 15 | 1.72 | 8.9 |
Total 4 quadrates 20 × 20 m2 sampling size was selected within the 4 natural forest areas. These forest areas were categorized in EIA study as a direct impact zone of the project. All quadrates were established in the same size and locations covering 0.16 ha area as measured during EIA study in 1995. A total 18 species, 17 genera and 260 individuals of different forest species with lower numbers of species and higher numbers of individuals were observed during this study. While, the species composition recorded during EIA study were 20 species 18 genera and 88 individuals (
Among the 18 species recorded in 4 quadrates in 0.16 ha area, Panserpu community forest above Adit A of the project showed the highest (13) number of species, while, Khajilung and Bhairabkunda Larcha forests showed 10 and 8 species respectively. The lowest of 5 species was found in the Thuloban CF above disposal site of the project (
The species-area curve mathematically showed the increasing trend of species to certain limits of constant during EIA study in 1995 and this study (
The dominance of 4 species (Caryopteris odorata, Alnus nepalensis, Acer oblongum, Litsea elongeta), together with their contribution of 58.4% of the total stand density indicates utilizing the majority of forest space and resources (
Simpsons Index (D) of species diversity was 0.0397, suggesting higher diversity in 1ha area. Likewise, Shannon-Weiner index of species diversity (H) was found 2.798; however, Shannon’s Max (Hmax) value is 2 and Species equitability (E) 0.9683. The value obtained for Simpson’s index of diversity is not surprising as the forest area is highly diverse (referring to the result from y). As shown below in the
SN | Location | No of Quadrates/Size (20 × 20 m2) | Total Species | Total Genera | Total Individuals | Total Area (ha) |
---|---|---|---|---|---|---|
During EIA 1995 | ||||||
1 | Panserpu | 1 | 11 | 9 - 2 | 38 | 400 m2 (0.04) |
2 | Kajilung | 1 | 3 | 3 | 10 | 400 m2 (0.04) |
3 | Bhairabkunda | 1 | 5 | 5 | 12 | 400 m2 (0.04) |
4 | Thuloban | 1 | 1 | 1 | 28 | 400 m2 (0.04) |
Total | 4 | 20 | 18 | 88 | 1600 m2 (0.16) | |
During this study | ||||||
1 | Panserpu | 1 | 13 | 13 | 111 | 400 m2 (0.04) |
2 | Kajilung | 1 | 13 + 2 | 13 + 2 | 43 | 400 m2 (0.04) |
3 | Bhairabkunda | 1 | 15 + 2 | 15 + 2 | 51 | 400 m2 (0.04) |
4 | Thuloban | 1 | 17 + 1 | 17 + 0 | 55 | 400 m2 (0.04) |
Total | 4 | 18 | 17 | 260 | 1600 m2 (0.16) |
Sampling plots | |||||||||
---|---|---|---|---|---|---|---|---|---|
SN | Scientific Name | Nepali Name | Family | Plant Form | 1 | 2 | 3 | 4 | Total |
1 | Alnus nepalensis | Utis | Betulaceae | Tree | - | + | + | - | 2 |
2 | Acer oblongum | Firfere | Aceraceae | Tree | + | - | - | + | 2 |
3 | Actinodaphne anguistifolia | Jhankri kath | Lauraceae | Tree | + | - | - | - | 1 |
4 | Albizzia chinensis | Siris | Leguminosae | Tree | - | - | + | - | 1 |
5 | Arundinaria falcata | Nigalo | Poaceae | Shrub | + | + | - | - | 2 |
6 | Caesalpinia decapitala | Arilokanda | Leguminosae | Shrub | + | - | + | - | 2 |
7 | Caryopteris odorata | Mohani | Verbinaceae | Tree | + | + | + | + | 4 |
8 | Litsea elongeta | Pahale | Lauraceae | Tree | + | - | + | - | 2 |
9 | Macaranga denticulata | Malato | Euphorbiaceae | Tree | + | - | - | - | 1 |
10 | Maesa chisia | Bilaone | Myrsinaceae | Shrub | + | + | + | - | 3 |
11 | Myrica esculanta | Kafal | Myricaceae | Tree | - | + | - | - | 1 |
12 | Persea ghamblei | Kathekaulo | Lauraceae | Tree | + | - | + | - | 2 |
13 | Pinus wallichiana | Sallo | Pinanceae | Tree | - | - | - | + | 1 |
14 | Rhus javanica | Bhakmilo | Anarcadaceae | Tree | + | - | + | - | 2 |
15 | Rhus succedanes | Bhalyao | Anarcadaceae | Tree | + | + | - | - | 2 |
16 | Schima wallichii | Chilaone | Theaceae | Tree | + | + | + | + | 4 |
17 | Symplocus pyrifolia | Kharane | Symplocaceae | Tree | - | - | + | + | 2 |
18 | Toona ciliata | Tooni | Meliaceae | Tree | + | + | - | - | 2 |
Total | 13 | 8 | 10 | 5 | 36 |
Note: 1 = Panserpu, 2 = Bhairabkunda, 3 = Khajilung, 4 = Thuloban, += Presence, -= Absence.
Sampling Plots | Total | Density Per plot | Relative Density | Abundance | |||||
---|---|---|---|---|---|---|---|---|---|
SN | Scientific Name | 1 | 2 | 3 | 4 | ||||
1 | Alnus nepalensis | 0 | 8 | 19 | 0 | 27 | 1.215 | 10.38 | 6.75 |
2 | Macaranga denticulata | 1 | 0 | 0 | 0 | 1 | 0.045 | 0.38 | 0.25 |
3 | Maesa chisia | 6 | 10 | 7 | 0 | 23 | 1.035 | 8.85 | 5.75 |
4 | Arundinaria falcata | 1 | 20 | 0 | 0 | 21 | 0.945 | 8.08 | 5.25 |
5 | Actinodaphne anguistifolia | 1 | 0 | 0 | 0 | 1 | 0.045 | 0.38 | 0.25 |
6 | Litsea elongeta | 21 | 0 | 6 | 0 | 27 | 1.215 | 10.38 | 6.75 |
7 | Rhus succedanes | 1 | 1 | 0 | 0 | 2 | 0.09 | 0.77 | 0.5 |
8 | Toona ciliata | 3 | 1 | 0 | 0 | 4 | 0.18 | 1.54 | 1 |
9 | Caesalpinia decapitala | 1 | 0 | 1 | 0 | 2 | 0.09 | 0.77 | 0.5 |
10 | Schima wallichii | 3 | 1 | 5 | 8 | 17 | 0.765 | 6.54 | 4.25 |
11 | Persea ghamblei | 2 | 0 | 1 | 0 | 3 | 0.135 | 1.15 | 0.75 |
12 | Acer oblongum | 14 | 0 | 0 | 19 | 33 | 1.485 | 12.69 | 8.25 |
13 | Rhus javanica | 2 | 0 | 1 | 0 | 3 | 0.135 | 1.15 | 0.75 |
14 | Caryopteris odorata | 56 | 1 | 4 | 4 | 65 | 2.925 | 25 | 16.25 |
15 | Myrica esculanta | 0 | 1 | 0 | 0 | 1 | 0.045 | 0.38 | 0.25 |
16 | Albizzia chinensis | 0 | 0 | 6 | 0 | 6 | 0.27 | 2.31 | 1.5 |
17 | Symplocus pyrifolia | 0 | 0 | 1 | 6 | 7 | 0.315 | 2.69 | 1.75 |
18 | Pinus wallichiana | 0 | 0 | 0 | 18 | 18 | 0.81 | 6.92 | 4.5 |
Total | 111 | 43 | 51 | 55 | 260 | 11.7 | 100 | 65.25 |
Species name | Observed abundance | % | Shannon’s Diversity | Simpson | ||||
---|---|---|---|---|---|---|---|---|
ln pi | pi (ln pi) | pi(ln pi)2 | ni(ni − 1) | N(N − 1) | Di | |||
Alnus nepalensis | −2.89037 | −0.16058 | 0.464125 | 2 | 1260 | 0.001587 | ||
Acer oblongum | 2 | 5.56 | −2.89037 | −0.16058 | 0.464125 | 2 | 1260 | 0.001587 |
Actinodaphne anguistifolia | 1 | 2.78 | −3.58352 | −0.09954 | 0.356711 | 0 | 1260 | 0 |
Albizzia chinensis | 1 | 2.78 | −3.58352 | −0.09954 | 0.356711 | 0 | 1260 | 0 |
Arundinaria falcata | 2 | 5.56 | −2.89037 | −0.16058 | 0.464125 | 2 | 1260 | 0.001587 |
Caesalpinia decapitala | 2 | 5.56 | −2.89037 | −0.16058 | 0.464125 | 2 | 1260 | 0.001587 |
Caryopteris odorata | 4 | 11.11 | −2.19722 | −0.24414 | 0.536422 | 12 | 1260 | 0.009524 |
Litsea elongeta | 2 | 5.56 | −2.89037 | −0.16058 | 0.464125 | 2 | 1260 | 0.001587 |
Macaranga denticulata | 1 | 2.78 | −3.58352 | −0.09954 | 0.356711 | 0 | 1260 | 0 |
Maesa chisia | 3 | 8.33 | −2.48491 | −0.20708 | 0.514563 | 6 | 1260 | 0.004762 |
Myrica esculanta | 1 | 2.78 | −3.58352 | −0.09954 | 0.356711 | 0 | 1260 | 0 |
Persea ghamblei | 2 | 5.56 | −2.89037 | −0.16058 | 0.464125 | 2 | 1260 | 0.001587 |
Pinus wallichiana | 1 | 2.78 | −3.58352 | −0.09954 | 0.356711 | 0 | 1260 | 0 |
Rhus javanica | 2 | 5.56 | −2.89037 | −0.16058 | 0.464125 | 2 | 1260 | 0.001587 |
Rhus succedanes | 2 | 5.56 | −2.89037 | −0.16058 | 0.464125 | 2 | 1260 | 0.001587 |
Schima wallichii | 4 | 11.11 | −2.19722 | −0.24414 | 0.536422 | 12 | 1260 | 0.009524 |
Symplocus pyrifolia | 2 | 5.56 | −2.89037 | −0.16058 | 0.464125 | 2 | 1260 | 0.001587 |
Toona ciliata | 2 | 5.56 | −2.89037 | −0.16058 | 0.464125 | 2 | 1260 | 0.001587 |
In previous study in 1995, altogether 20 species were recorded in 0.16 ha area with Litsea chartacea and Maesa chisia species covering highest abundance (9.67%) while each of the 11 species were found covering lowest abundance (3.22%) and the rest of 7 species were recorded covering 6.45% abundance each. The result reveals in 1995 there was diversity in species composition without dominance of single species (
In 3 quadrates studied in natural forests, total 61 trees belonging to 9 genera and 9 species were recorded. Quadrate 2 composed of highest number of species (5) with lowest basal area (2.3 m2) and tree volume (11.43 m3) while quadrate 3 was found with lowest number of species together with highest basal area (6.2 m2) and tree volume (62.47 m3) (
The environmental impacts in the study area observed at range of spatial and temporal scales. Temporal fluctuations of environmental factors change biodiversity constantly over different scales. Natural population and communities of taxa turnover means origination and extinction predominantly in global scales, and colonization and disappearance at local to continental scale [
Species name | Observed abundance | % Abd. | Shannon’s | Simpson | ||||
---|---|---|---|---|---|---|---|---|
ln pi | pi (ln pi) | pi(ln pi)2 | ni(ni − 1) | N(N − 1) | Di | |||
Acer oblongum | 2 | 6.45 | −2.74084 | −0.17683 | 0.484658 | 2 | 930 | 0.002151 |
Actinodaphne anguistifolia | 2 | 6.45 | −2.74084 | −0.17683 | 0.484658 | 2 | 930 | 0.002151 |
Alnus nepalensis | 2 | 6.45 | −2.74084 | −0.17683 | 0.484658 | 2 | 930 | 0.002151 |
Caryopteris odorata | 1 | 3.23 | −3.43399 | −0.11077 | 0.380396 | 0 | 930 | 0 |
Leucosceptrum canum | 1 | 3.23 | −3.43399 | −0.11077 | 0.380396 | 0 | 930 | 0 |
Litsea chartacea | 3 | 9.68 | −2.33537 | −0.226 | 0.527804 | 6 | 930 | 0.006452 |
Litsea doshia | 2 | 6.45 | −2.74084 | −0.17683 | 0.484658 | 2 | 930 | 0.002151 |
Litsea elongate | 1 | 3.23 | −3.43399 | −0.11077 | 0.380396 | 0 | 930 | 0 |
Lyonia ovlifolia | 1 | 3.23 | −3.43399 | −0.11077 | 0.380396 | 0 | 930 | 0 |
Macaranga denticulata | 1 | 3.23 | −3.43399 | −0.11077 | 0.380396 | 0 | 930 | 0 |
Maesa chisia | 3 | 9.68 | −2.33537 | −0.226 | 0.527804 | 6 | 930 | 0.006452 |
Persea gamblei | 2 | 6.45 | −2.74084 | −0.17683 | 0.484658 | 2 | 930 | 0.002151 |
Pinus roxburgii | 1 | 3.23 | −3.43399 | −0.11077 | 0.380396 | 0 | 930 | 0 |
Pinus wallichiana | 1 | 3.23 | −3.43399 | −0.11077 | 0.380396 | 0 | 930 | 0 |
Quercus leucotrichophora | 2 | 6.45 | −2.74084 | −0.17683 | 0.484658 | 2 | 930 | 0.002151 |
Rhododendron arboretum | 1 | 3.23 | −3.43399 | −0.11077 | 0.380396 | 0 | 930 | 0 |
Rhus javanica | 2 | 6.45 | −2.74084 | −0.17683 | 0.484658 | 2 | 930 | 0.002151 |
Schima wallichii | 1 | 3.23 | −3.43399 | −0.11077 | 0.380396 | 0 | 930 | 0 |
Symplocus pyrifolia | 1 | 3.23 | −3.43399 | −0.11077 | 0.380396 | 0 | 930 | 0 |
Toona cialiata | 1 | 3.23 | −3.43399 | −0.11077 | 0.380396 | 0 | 930 | 0 |
Source: EIA Study 1995, IUCN Nepal.
Period | Shannon’s Diversity | Simpson’s | |||
---|---|---|---|---|---|
H’ | E | Var H’ | D | 1/D | |
2015 | 2.799 | 0.967 | −0.002 | 0.034 | 25.2 |
1995 | 2.909 | 0.971 | −0.0043 | 0.028 | 35.77 |
Plots | SN | Scientific Name | Local Name | No. | BA (m2) | Timber Volume (m3) |
---|---|---|---|---|---|---|
1 | 1 | Toona ciliata | Tooni | 2 | 0.21 | 0.63 |
2 | Litsea elongeta | Pahale | 10 | 4.64 | 16.77 | |
3 | Actinodaphne anguistifolia | Jhankri kath | 1 | 0.07 | 0.14 | |
4 | Rhus javanica | Bhalayo | 1 | 0.79 | 4.71 | |
Total | 14 | 5.71 | 22.26 | |||
2 | 1 | Rhus javanica | Bhalayo | 1 | 0.07 | 0.18 |
2 | Myrica esculanta | Kafal | 1 | 0.2 | 0.79 | |
3 | Alnus nepalnesis | Utis | 2 | 0.6 | 3.4 | |
4 | Macarabga denticulata | Malato | 2 | 1.01 | 4.48 | |
5 | Toona ciliata | Tooni | 1 | 0.43 | 2.58 | |
Total | 7 | 2.3 | 11.43 | |||
3 | 1 | Pinus wallichiana | Rani Sallo | 17 | 5.28 | 62.01 |
2 | Schima wallichii | Chilaone | 2 | 0.92 | 0.46 | |
Total | 61 | 6.2 | 62.47 |
Structuring of the forest communities is influence by the disturbance, as an important factor [
According to the pervious study, (EIA of UBHP, 1995), Alnus nepalensis was recorded with the highest relative dominance followed by Pinus roxburgii and Litsea chartacea on the basis of the basal area. Pinus wallichiana was recorded with the highest importance value which may be attributed to its pure stand in a localized area. Likewise, importance value of Alnus nepalensis and Quercus leucotrichophora were also shown exceeding the value of 26, while Lyonia ovlifolia had the lowest importance value. 41.57 m3 of total standing volume was calculated for all species in the sample plots. In terms of species, Alnus nepalensis reported covering 9m3 followed by Pinus roxburgii (6 m3). The sample plot 3 (Forest North to Larcha) reported with the highest timber volume (nearly 13 m3) followed by plot 1 (forest below Panserpu village).
In this study, highest basal area (5.27 m2) and volume (62.01 m3) of Pinus wallichiana was found in plot 4 (Thulo Ban CF) followed by Schima wallichii in plot 3 (Khajilung CF). Likewise, Litsea elongeta in plot 2 (Bhairabkunda) calculated basal area of 4.63 m2 and timber volume of 16.77 m3 which is followed by Actinodaphne anguistifolia, Toona cialita and Rhus javanica in plot 1 (Panserpu forest). The plot 2 has shown the lowest calculated BA and timber volume however 1995 showed the highest timber volume. Thus, the study concludes that the Larcha forest is the most disturbed forest of the project area.
According to EIA monitoring report, 150 trees at headwork and a tree of Michelia champaca at audit were cleared and Artemisia vulgaris, Arundinaria intermedia and Alnus nepalensis proposed as a compensatory measures for reforestation. However, the present study assessed abundant number of regenerated and planted individuals the species composition is found in decreasing trend in natural forests. Besides that, the regenerated area is found dominated by unwanted species of herbs and shrubs like Eupatorium adennophorum, Cyathula capitata and Artimesia valguris.
Beier et al., 2008 [
Floristic composition and species diversity in pervious and this study revealed changes on species, genera and family at the ratio of 2:1:2. Similarly, Simpsons index (D), Shannon’s Diversity (H) and Species equitability (E) are also found decreasing at the ratio of −0.014:40.0419:007 (
Sampling Size | Pervious Study 1995 | Present Study | Difference | Impact of Change |
---|---|---|---|---|
Number of Quadrates | 4 | 4 | No | - |
Total Area | 1600 m2 | 1600 m2 | No | - |
Total Numbers of Species | 20 | 18 | 2 | Decreasing trend of sps |
Total Numbers of Genera | 18 | 17 | 1 | Change |
Total Numbers of Family | 15 | 13 | 2 | Change |
Diversity Index | ||||
Simpson’s index (D)- | 0.027 | 0.039 | −0.014 | Decreasing |
Shannon’s Diversity (H)- | 2.908 | 2.879 | 0.041 | Decreasing |
Shannon’s Max (Hmax)- | 2 | 2 | 0 | No change |
Species equitability (E)- | 0.9753 | 0.9683 | 0.007 | Decreasing |
The regeneration properties of the vegetation plots showed relatively at stable state (with canopy and sub-canopy species regenerating) while other plots are at transitional stage, possibly due to disturbance. It is apparent that once disturbed plots can regenerate to a forest environment based on time-series data. Regenerating and tree recruitment appeared to be difficult in previously disturbed plots forest due to dominance of shrub layer. However, no new endemic, or invasive, species were recorded in the regenerating areas; abundance of unwanted species was observed. According to F. Stuart Chapin, et al., 2000 [
The natural forest studied comprises community forests managed by the local communities. According to Shrestha and Paudel, 1996 [
Strengthening local control, strongly implementation of EIA mitigation measures in project influence area and policy oversight is urgently needed to assure long-term sustainability of the project and maintaining integrity of the local environment [
Despite the increasing area for quadrate sample, there is still lack of rich biodiversity in regenerated or planted area however Ecologists have produced hundreds of examples of increasing species diversity with increasing area [
The local and regional climate, topographic position, disturbances, environmental factors and biotic interactions determine forest structure and composition [
Thus, the low regeneration properties in the project influence area could be assume due to immense disturbance and varied range of requirements to tolerate the environmental condition. The long term capacity of forests to maintain biodiversity is the global concern for supply of goods and services (including carbon storage, food, clean water, and recreation). It is augmented following pragmatic impacts occurring to global forests as a result of climate change [
Abiotic factors plays important role to change species composition and reduction of the diversity. Similarly, different pathways of climatic effects on multiple species results habitat effects and differing effects of invasions at local vs regional to global scales [
According to Zomer et al., 2001 [
The study concludes that the species diversity in the study area is in declining trend with decreased species composition in both natural and regenerated forests due to intensive pressure. Abundance of Alnus nepalensis with high relative dominance followed by Pinus roxburgii and Litsea chartacea in 1995 is replaced by Litsea elongeta followed by Actinodaphne anguistifolia, Toona cialita and Rhus javanica in this study which is the result of long-term interactions between the vegetation and site factors over time and space.
The disturbed forest slopes were found with low species diversity and abundance of single species. Moreover, growth of unwanted or alien species found spreading over the regenerated area. An ineffective implementation of policies, slight overlook of the impacts and prediction methods, absence of major changes in policy and human behavior, effects on the environment will continue to alter biodiversity, change land-use and increase atmospheric CO2. Thus, effective management of forest with intensive control on human disturbance could protect the natural integrity of forest ecosystem.
RameshPrasad Bhatt,SaralaBhatt, (2016) Floristic Composition and Change in Species Diversity over Long Temporal Scales in Upper Bhotekoshi Hydropower Project Area in Nepal. American Journal of Plant Sciences,07,28-47. doi: 10.4236/ajps.2016.71004