The study made an assessment of the floral status of the project site of Kotlibhel hydrolectric project (Stage 1B) at Alaknanda valley in the Ganga river system (India). Study area included two broad zones: Influence (IZ) and Submergence zone (SZ). Influence zone showed higher species richness in all vegetation strata. In the upper layer, there were 26 tree species, middle layer consisted of 32 shrub species and ground layer (understory) contained 41 species. Maximum density in the tree layer (36.4 plants/ha) was found for
Forests are being degraded and fragmented rapidly in the Indian subcontinent. The human influences on biodiversity and ecosystem are rapid and large, leading to frequent changes in land and resource use, increased frequency of biotic invasions, reduction in species number, creation of stresses and the potential for changes in the climate system (
To analyze plant diversity, a study was conducted in the area of about 350 km2 along rivers Alaknanda and Ganga between Srinagar and Devprayag. The area covers a stretch of about 30 km long and 7 km wide.
The vegetational analysis was conducted since June 2005 to Feb 2006. The study area was divided into two subareas: “Influence zone” (IZ) and “Submergence zone” (SZ) along the reservoir, as proposed by the Dam authority. The area subjected to submersion up to full reservoir level (FRL - approx. 325 m a.s.l.) was considered as submergence zone and the area along the reservoir up to 7 km radius around the reservoir was considered as influence zone. Some 8 transects were analyzed in the entire study area: Supana-Sundari, Switpul-Swit, Bhallagaun-Hakgaun, Bagwan-Golta, Mullagaun-Kothi, Gunkhal-Semi, Dhanchera-Pali and Saud- Sariyakhal. Each transect was 1500 m long, from the river water level along an increasing altitudinal gradient (
Within each 10 m radius plot, a nested circular plot of 5 m radius was sampled for recording shrubs, whereas four nested circular plots of 1 m radius were established for herbs analisys. Herbs were recorded by point-intercept method for their proportional representation in the area. In order to prepare a checklist and best represent the species from the area, an intensive search was made by re-tracing belt transects in three different seasons.
Species characterized by short stature, including annual or biennial herbs, and by spiny structures (thorns and spines) were classified as shrubs. Herbs included shade- loving, annual, biennial or perennial, herbaceous species. Trees with cbh (circumference at breast height, i.e., 1.37 m above the ground) > 31.5 cm were individually counted in the 10 m radius plot. Herbarium sheets of species which could not be identified in the field were prepared, and identified later at the Department of Botany, HNB Garhwal University.
Frequency, density, abundance and their relative values for each species were obtained using the equations reported below (
AF ratio for different species was determined for eliciting the distribution pattern in terms of regular (AF<0.025), random (AF=0.025-0.05) and contagious (AF>0.05), as follows (
The Shannon’s (
where
Species richness (SR) was calculated (
where S is the number of species and N the total number of individuals of all species.
In tree layer of IZ, maximum density (36.4 plants/ha) and frequency (95.8 %) was observed for
In the IZ shrub layer,
In the IZ herb layer,
The abundance/frequency ratios (A/F) obtained showed that most of species were contagiously distributed in both IZ and SZ. In the tree layer, 84.5 % species were found in contagious pattern within IZ and 15.4% were randomly distributed. For shrubs in the IZ, 50% species were in contagious and 50% in random distribution, while in SZ 95.8% species were in contagious distribution and 4.2 % were in regular distribution pattern (
Among all vegetation layer of IZ and SZ, the maximum number of species was encountered for the herb layer of IZ (41) and the minimum (20) for the tree layer in the SZ. Shannon diversity (
Shannon and Simpson diversity indices for tree layer did not show significant differences between IZ and SZ after
Disturbance has become a widespread feature in most of the forest all over the Himalaya (
The changes in the dispersion patterns may reflect the reactions of species to disturbance, as well as to changes in the habitat conditions (
Shannon species diversity (H′) and concentration of dominance (cd) of the present study sites are more or less similar to the values reported by
Species richness in out study showed higher values for ground vegetation (herbs), followed by shrubs and trees.
The vegetation of the study area is important for sustaining the livelihood of local people. The present study suggests that the influence zone has the maximum species diversity and richness. Diversity was high where the dominance of canopy species was major and low near agricultural fields or on disturbed sites. The vegetation composition of both zones was found almost in similar pattern, though species richness was larger in the Influence zone. Hence, it may be hypothesized that after construction of proposed hydropower project there may be negligible effect on the species richness of the surrounding vegetation, but definitely a significant portion of the vegetation is going to be lost for ever. The change in landuse of riverine belt might also change the micro habitat requirement of many species. This of course require detailed investigation in order to conclude species specific impact of the proposed hydropower project.
The study area.
Vegetational characteristics of tree species in the Influence and Submergence zones of the study area. (NR): species present but not recorded within sampled quadrate; (Abs): absent. For the list of additional species found outside the sample plots, see Tab. SM1 in Supplementary Material.
Species | Influence zone | Submergence zone | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
Den | Abu | Fre | IVI | A/F | Den | Abu | Fre | IVI | A/F | |
|
7.3 | 1.83 | 12.5 | 9.25 | 0.15 | 22.5 | 2.33 | 18.8 | 29.31 | 0.1 |
|
9.3 | 2 | 14.6 | 10.05 | 0.14 | 13.9 | 2.62 | 27.1 | 14.24 | 0.12 |
|
4 | 2 | 6.3 | 3.53 | 0.32 | 2 | 1 | 6.3 | 3.71 | 0.16 |
|
2.7 | 1.33 | 6.3 | 3.67 | 0.21 | Abs | ||||
|
4 | 1.5 | 8.3 | 9.65 | 0.18 | 9.3 | 2 | 14.6 | 10.64 | 0.14 |
|
1.3 | 1 | 4.2 | 1.63 | 0.24 | NR | ||||
|
2 | 1.5 | 4.2 | 2.61 | 0.36 | 6.6 | 3.33 | 6.3 | 6.46 | 0.53 |
|
NR | 1.3 | 2 | 2.1 | 1.73 | 0.96 | ||||
|
2 | 1 | 6.3 | 4.07 | 0.16 | 2 | 1.5 | 4.2 | 3.45 | 0.36 |
|
0.7 | 1 | 2.1 | 1.74 | 0.48 | Abs | ||||
|
Abs | 4.6 | 7 | 2.1 | 11.14 | 3.36 | ||||
|
NR | 3.3 | 2.5 | 4.2 | 3.55 | 0.6 | ||||
|
NR | 2.7 | 4 | 2.1 | 3.76 | 1.92 | ||||
|
36.4 | 1.2 | 95.8 | 46.99 | 0.01 | 8 | 4 | 6.3 | 8.73 | 0.64 |
|
29.2 | 1.19 | 77.1 | 37.55 | 0.02 | 26.5 | 3.08 | 27.1 | 23.87 | 0.11 |
|
1.3 | 2 | 2.1 | 1.43 | 0.96 | Abs | ||||
|
3.3 | 1.25 | 8.3 | 7.06 | 0.15 | 33.8 | 3.4 | 31.3 | 31.71 | 0.11 |
|
4 | 2 | 6.3 | 4.38 | 0.32 | 9.3 | 2.8 | 10.4 | 8.68 | 0.27 |
|
27.8 | 1.2 | 72.9 | 33.57 | 0.02 | 25.8 | 2.6 | 31.3 | 26.14 | 0.08 |
|
6.6 | 2.5 | 8.3 | 23.6 | 0.3 | 12.6 | 2.71 | 14.6 | 58.77 | 0.19 |
|
4 | 2 | 6.3 | 4.34 | 0.32 | 6 | 3 | 6.3 | 5.55 | 0.48 |
|
4 | 3 | 4.2 | 4.29 | 0.72 | NR | ||||
|
2.7 | 2 | 4.2 | 2.29 | 0.48 | Abs | ||||
|
NR | 1.3 | 1 | 4.2 | 6.71 | 0.24 | ||||
|
2 | 1.5 | 4.2 | 2.05 | 0.36 | Abs | ||||
|
33.1 | 1.16 | 89.6 | 71.88 | 0.01 | 32.5 | 3.5 | 29.2 | 38.96 | 0.12 |
|
1.3 | 1 | 4.2 | 1.64 | 0.24 | Abs | ||||
|
4.6 | 2.33 | 6.3 | 4.52 | 0.37 | NR | ||||
|
1.3 | 1 | 4.2 | 2.24 | 0.24 | Abs | ||||
|
1.3 | 2 | 2.1 | 2.11 | 0.96 | 1.3 | 2 | 2.1 | 2.91 | 0.96 |
|
3.3 | 1.25 | 8.3 | 3.84 | 0.15 | NR | ||||
Total | 199.4 | - | - | 300 | - | 225.3 | - | - | 300 | - |
Vegetational characteristics of shrub species in the Influence and Submergence zones of the study area. (NR): species present but not recorded within sampled quadrate; (Abs): absent. For the list of additional species found outside the sample plots, see Tab. SM2 in Supplementary Material.
Species | Influence zone | Submergence zone | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
Den | Abu | Fre | IVI | A/F | Den | Abu | Fre | IVI | A/F | |
|
299.9 | 2.8 | 83.3 | 9.3 | 0.03 | 146 | 1.49 | 77.1 | 15.12 | 0.02 |
|
66.4 | 1.5 | 35.4 | 3.1 | 0.04 | 53.1 | 3.33 | 12.5 | 3.23 | 0.27 |
|
108.8 | 2.4 | 35.4 | 3.7 | 0.07 | 45.1 | 3.4 | 10.4 | 2.72 | 0.33 |
|
400.8 | 3.4 | 93.8 | 11.4 | 0.04 | 47.8 | 3.6 | 10.4 | 2.79 | 0.35 |
|
100.9 | 5.4 | 14.6 | 2.3 | 0.37 | NR | ||||
|
74.3 | 3.5 | 16.7 | 2.1 | 0.21 | 106.2 | 3.33 | 25 | 6.46 | 0.13 |
|
467.1 | 3.7 | 100 | 12.7 | 0.04 | 42.5 | 2 | 16.7 | 3.56 | 0.12 |
|
98.2 | 3.4 | 22.9 | 2.8 | 0.15 | 61 | 2.09 | 22.9 | 4.96 | 0.09 |
|
456.5 | 4 | 89.6 | 11.9 | 0.05 | NR | ||||
|
355.7 | 2.8 | 100 | 11.1 | 0.03 | 506.9 | 4.66 | 85.4 | 25.9 | 0.06 |
|
169.9 | 1.8 | 72.9 | 6.8 | 0.03 | 124.7 | 3.13 | 31.3 | 7.87 | 0.1 |
|
164.6 | 4.1 | 31.3 | 4.2 | 0.13 | 39.8 | 2.14 | 14.6 | 3.18 | 0.15 |
|
55.7 | 4.2 | 10.4 | 1.4 | 0.4 | 90.2 | 4.25 | 16.7 | 4.82 | 0.26 |
|
47.8 | 3 | 12.5 | 1.4 | 0.24 | 18.6 | 2.33 | 6.3 | 1.4 | 0.37 |
|
292 | 2.8 | 83.3 | 9.2 | 0.03 | 8 | 1.5 | 4.2 | 0.82 | 0.36 |
|
63.7 | 2.7 | 18.8 | 2 | 0.14 | 18.6 | 2.33 | 6.3 | 1.4 | 0.37 |
|
103.5 | 2.6 | 31.3 | 3.4 | 0.08 | 844 | 7.57 | 89.6 | 35.14 | 0.09 |
|
453.9 | 3.6 | 100 | 12.5 | 0.04 | 499 | 4.7 | 83.3 | 25.39 | 0.06 |
|
589.2 | 4.6 | 100 | 14.5 | 0.05 | 29.2 | 2.2 | 10.4 | 2.29 | 0.21 |
|
84.9 | 3.6 | 18.8 | 2.3 | 0.19 | 100.9 | 4.75 | 16.7 | 5.11 | 0.29 |
|
63.7 | 4 | 12.5 | 1.7 | 0.32 | 809.5 | 7.09 | 87.5 | 34.53 | 0.08 |
|
61 | 1.9 | 25 | 2.4 | 0.08 | NR | ||||
|
90.2 | 1.7 | 41.7 | 3.8 | 0.04 | NR | ||||
|
445.9 | 3.7 | 93.8 | 12 | 0.04 | 8 | 1.5 | 4.2 | 0.82 | 0.36 |
|
483.1 | 3.8 | 100 | 12.9 | 0.04 | NR | ||||
|
464.5 | 3.8 | 95.8 | 12.4 | 0.04 | Abs | ||||
|
98.2 | 1.4 | 54.2 | 4.7 | 0.03 | NR | ||||
|
236.2 | 3.7 | 50 | 6.4 | 0.07 | 50.4 | 4.75 | 8.3 | 2.55 | 0.57 |
|
50.4 | 2.4 | 16.7 | 1.7 | 0.14 | 10.6 | 2 | 4.2 | 0.89 | 0.48 |
|
172.5 | 2.6 | 52.1 | 5.6 | 0.05 | 21.2 | 2 | 8.3 | 1.78 | 0.24 |
|
90.2 | 3.4 | 20.8 | 2.5 | 0.16 | NR | ||||
|
252.1 | 5.6 | 35.4 | 5.7 | 0.16 | 90.2 | 2.13 | 33.3 | 7.26 | 0.06 |
Total | 6961.9 | - | - | 200 | - | 3771.6 | - | - | 200 | - |
Vegetational characteristics of herb species in the Influence and Submergence zones of the study area. (NR): species present but not recorded within sampled quadrate; (Abs): absent. For the list of additional species found outside the sample plots, see Tab. SM3 in Supplementary Material.
Species | Influence zone | Submergence zone | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
Den | Abu | Fre | IVI | A/F | Den | Abu | Fre | IVI | A/F | |
|
1791.4 | 0.97 | 44.3 | 6.3 | 0.03 | 1161.1 | 2.05 | 19.8 | 2.97 | 0.09 |
|
2023.6 | 1.07 | 43.2 | 6.58 | 0.03 | 2023.6 | 1.83 | 29.7 | 4.82 | 0.07 |
|
1227.4 | 1.73 | 29.7 | 4.27 | 0.04 | Abs | ||||
|
879.1 | 2.43 | 14.1 | 2.49 | 0.14 | 1857.7 | 1.3 | 29.7 | 4.6 | 0.07 |
|
1061.6 | 1.54 | 15.1 | 2.86 | 0.15 | NR | ||||
|
1940.7 | 2 | 42.7 | 6.41 | 0.03 | Abs | ||||
|
597.1 | 1.96 | 8.9 | 1.63 | 0.24 | 1459.7 | 2 | 16.7 | 3.12 | 0.17 |
|
1210.8 | 1.51 | 15.6 | 3.13 | 0.16 | 3715.5 | 1.43 | 58.3 | 9.13 | 0.03 |
|
1327 | 1.79 | 27.6 | 4.26 | 0.06 | 2537.8 | 1.37 | 37.5 | 6.06 | 0.06 |
|
5506.9 | 1.45 | 100 | 16.52 | 0.02 | 1310.4 | 1.96 | 30.2 | 3.94 | 0.05 |
|
2040.2 | 1.66 | 51 | 7.22 | 0.03 | 1808 | 2.13 | 31.3 | 4.66 | 0.06 |
|
663.5 | 1.47 | 13.5 | 2.11 | 0.11 | 1426.5 | 1.48 | 31.3 | 4.17 | 0.05 |
|
3781.8 | 1.76 | 100 | 13.81 | 0.01 | 4362.4 | 1.22 | 43.2 | 8.83 | 0.07 |
|
2703.7 | 2.75 | 49 | 8.1 | 0.04 | 928.9 | 1.45 | 22.4 | 2.87 | 0.06 |
|
829.3 | 2.16 | 12 | 2.25 | 0.18 | 2040.2 | 2.14 | 42.7 | 5.81 | 0.04 |
|
1409.9 | 1.56 | 18.8 | 3.69 | 0.13 | 1973.9 | 2.87 | 24 | 4.32 | 0.11 |
|
3018.8 | 2.04 | 97.4 | 12.41 | 0.01 | 5540.1 | 2.08 | 84.9 | 13.45 | 0.02 |
|
1575.8 | 1.43 | 19.8 | 4.03 | 0.13 | 1625.5 | 2.07 | 13.5 | 3.1 | 0.28 |
|
1310.4 | 1.43 | 14.1 | 3.16 | 0.21 | 1443.1 | 1.32 | 24.5 | 3.68 | 0.08 |
|
1244 | 1.43 | 25 | 3.92 | 0.06 | 1360.1 | 1.94 | 32.3 | 4.16 | 0.04 |
|
3416.9 | 1.8 | 100 | 13.24 | 0.01 | 1758.2 | 1.84 | 30.2 | 4.51 | 0.06 |
|
879.1 | 1.76 | 13.5 | 2.45 | 0.15 | 1111.3 | 1.82 | 21.4 | 3.02 | 0.08 |
|
978.6 | 2.36 | 14.6 | 2.69 | 0.14 | 1824.6 | 1.67 | 46.9 | 5.85 | 0.03 |
|
564 | 1.46 | 9.9 | 1.66 | 0.18 | 2007 | 2.59 | 42.7 | 5.77 | 0.04 |
|
1459.7 | 1.3 | 18.2 | 3.73 | 0.14 | 5457.1 | 2.05 | 89.6 | 13.7 | 0.02 |
|
NR | 5490.3 | 2.09 | 96.4 | 14.25 | 0.02 | ||||
|
514.2 | 2.23 | 9.9 | 1.59 | 0.17 | 1575.8 | 1.42 | 27.6 | 4.09 | 0.07 |
|
547.4 | 1.68 | 6.3 | 1.35 | 0.44 | 1277.2 | 1.82 | 19.3 | 3.08 | 0.11 |
|
1210.8 | 1.27 | 22.9 | 3.71 | 0.07 | 2471.5 | 1.85 | 53.6 | 7.18 | 0.03 |
|
1327 | 1.73 | 19.3 | 3.6 | 0.11 | 1509.4 | 1.36 | 22.9 | 3.65 | 0.09 |
|
2189.5 | 2.93 | 39.1 | 6.51 | 0.05 | 1426.5 | 1.91 | 15.6 | 3 | 0.18 |
|
1443.1 | 1.26 | 20.3 | 3.87 | 0.11 | 1210.8 | 1.79 | 18.2 | 2.92 | 0.11 |
|
1161.1 | 2.51 | 25 | 3.79 | 0.06 | 1327 | 3.17 | 20.3 | 3.22 | 0.1 |
|
1725 | 1.19 | 30.7 | 5.13 | 0.06 | Abs | ||||
|
912.3 | 2.17 | 14.1 | 2.54 | 0.15 | 1608.9 | 1.5 | 26 | 4.01 | 0.07 |
|
1177.7 | 2.21 | 25.5 | 3.86 | 0.06 | 2703.7 | 2.75 | 69.8 | 8.69 | 0.02 |
|
1874.3 | 2.12 | 41.1 | 6.18 | 0.04 | 1874.3 | 3.77 | 32.3 | 4.82 | 0.06 |
|
1310.4 | 2.5 | 24.5 | 3.99 | 0.07 | 1741.6 | 1.22 | 38.5 | 5.12 | 0.04 |
|
1127.9 | 2.11 | 17.7 | 3.17 | 0.11 | 2156.3 | 1.79 | 49.5 | 6.47 | 0.03 |
|
1111.3 | 1.63 | 22.9 | 3.55 | 0.07 | 1575.8 | 1.63 | 18.8 | 3.42 | 0.14 |
|
1327 | 2.04 | 29.2 | 4.38 | 0.05 | NR | ||||
|
1310.4 | 1.52 | 22.9 | 3.86 | 0.08 | 1327 | 2.64 | 25 | 3.57 | 0.07 |
Total | 63710.6 | - | - | 200 | - | 78008.6 | - | - | 200 | - |
Diversity indices and species richness in the both zone of study area. IZ: Influence Zone; SZ: Submergence Zone
Diversity indices | Tree | Shrub | Herb | |||
---|---|---|---|---|---|---|
IZ | SZ | IZ | SZ | IZ | SZ | |
Species Richness | 26 | 20 | 32 | 24 | 41 | 37 |
Shannon index (H) | 2.430 | 2.643 | 3.184 | 2.37 | 3.561 | 3.48 |
Simpson index (CD) | 0.134 | 0.086 | 0.050 | 0.138 | 0.034 | 0.036 |
Margalef index (SR) | 4.6 | 4.0 | 3.9 | 3.2 | 4.8 | 4.3 |