Ecophysiological studies in disturbed forest ecosystem: a case study at Pattikkad
Loading...
Files
Date
1993
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
College of Forestry, Vellanikkara
Abstract
Moist deciduous forests of Kerala are prone to comparatively more biotic interference, as it occupies a buffer zone between human population and evergreen forests. An investigation was carried out at Pattikkad range of Peechi- Vazhani wildlife Sanctuary, in Trichur Forest Division, Kerala. The objectives of the present study were to understand the floristic, structural, functional, physiological, edaphic and micrometeorological changes accompanying degradation. Three experimental plots namely highly disturbed ( PATK – BT), partially disturbed (PATK – MD) and more less undisturbed (PATK – TP) were identified taking into consideration the proximity to human settlement. Each plot had a size of 10000 m2 and were subdivided into quadrats having 100 m2 each and observations on frequency, density, basal area, Importance Value Index (IVI), diversity indices, height – diameter relationships, regeneration pattern, litter quantification, litter decomposition, phenology, leaf area, leaf area index, light infiltration, physic-chemical properties of soil, soil moisture and soil temperature were recorded at periodic intervals for an year.
The results indicate that the moist deciduous forest tend to become a semi – evergreen forest it left undisturbed for several years. The undisturbed (PATK – TP) plot recorded maximum density (882), in 143 species (48 families) whereas the density is only 154 in the highly disturbed (PATK – BT) plot. The number of species at PATK – BT is only 31 (19 families).
The species diversity is also very high in the undisturbed plot (Simpson’s index = 0.97 ; Shanon –Weiner’s index = 5.97) whereas the Simpson’s index and Shannon – Weiner’s index are 0.92 and 4.16 respectively for PATK – BT.
The height – diameter relationship clearly show that the set of the future is more or less absent in the disturbed plots. The regeneration survey reveals that the regenerating community is sparse in the disturbed plots. While the disturbed plots (PATK – BT and PATK – MD) had 3825 and 5045 seedlings per hectare the undisturbed (PATK – TP) plot had 26,500 seedlings per hectare.
The litter production was found to be positively correlated with basal area. The rate of litterfall ranged from 6.14 t ha-1 to 8.66 t ha-1 in the moist deciduous forests.
The decay rate was fastest in the disturbed (PATK – BT) plot (‘K’ value = 0.26) and slowest in the undisturbed (PATK – TP) plot (‘K’ value = 0.17).
The light infiltration to the forest floor was maximum in the highly disturbed (PATK – TP) plot (44.42 mol m-2 s-1 ).
The PATK – TP had a leaf area index of 4.04 and that of PATK BT was only 1.06
While most of the leaves in the undisturbed plot belonged to notophyllous (leaf size = 20.25 cm2 to 45.00 cm2 ) type of leaves, that of distributed plots were mesophyllous (leaf size = 45.00 cm2 to 182.25 cm2 ).
The physic – chemical properties of the soil were better in the undisturbed plot when compared to the disturbed plots. The gravel content was 23 to 33 per cent at PATK – BT whereas it was 22 to 23 per cent at PATK – TP. Soil was more acidic (pH 5.51 to 5.57 ) at PATK – TP, whereas at PATK – BT the pH varied from 6.13 to 6.14. The organic carbon at undisturbed (PATK – TP) plot ranged between 1.4 to 3 per cent while in the highly disturbed (PATK – BT) plot ranged from 0.9 to 2 per cent. N, P and K also followed a similar pattern.
The soil moisture was always maximum in the undisturbed (PATK –TP) plot. The soil moisture varied between 14 per cent (March) to 50 percent (July). The soil moisture at the highly disturbed (PATK – BT) plot was always the minimum. The values varied between 3 per cent (March) to 30 per cent (July).
The undisturbed (PATK – TP) plot consistently recorded minimum soil temperature throughout the year when compared to the disturbed plots. The values varied between 220 C (July) to 280 C (April). Whereas in the highly disturbed (PATK – BT) plot the soil temperature was always high. The soil temperature recorded at PATK – BT ranged between 250 C (July) to 360 C (April).
Description
PG
Keywords
null