PG Thesis

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Subject: search.filters.subject.Natural Resource Management

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    Influence of vegetation on the hydrologic characteristics of Irumbupalam and Mayiladumpara watersheds in Peechi - Vazhani wildlife sanctuary, Thrissur, Kerala
    (Department of Natural Resource Management, College of Forestry, Vellanikkara, 2022-10-25) Bhawane Akash Kailas; Gopakumar, S
    Forest vegetation and water are two valuable resources for mankind, and both the resources influence each other. It is important to understand the interrelationship between forest vegetation and hydrology. The present study was undertaken in Irumbupalam and Mayiladumpara watersheds in Peechi-Vazhani wildlife sanctuary, Thrissur, Kerala. The aim of the study was to identify and quantify the hydrological differences between these watersheds and assess the extent to which these differences are related to vegetation characteristics. Mayiladumpara watershed comprised of eight different land use classes of which mixed crops and trees accounts highest (27.91%) area whereas Irumbupalam comprised of three land use classes, of which, reserved forest occupied the highest (67.74%) of area. Within each watershed, twenty-two, 10 m x 10 m sample plots were laid out for detailed enumeration of vegetation and soil parameters. The Irumbupalam harbored a greater number of tree species (38) compared to the Mayiladumpara (28). The mean tree density ha-1 was higher in Mayiladumpara (586 individuals ha-1 ) compared to Irumbupalam (509 individuals ha-1 ). Similarly, the mean tree basal area was greater in Mayiladumpara (45.48 m2 ha-1 ) as compared to Irumbupalam (13.97 m2 ha-1 ). The tree diversity was found to be maximum in Irumbupalam watershed. Physico- chemical properties of soil viz. soil pH, organic carbon, water holding capacity, soil moisture and soil porosity showed showed higher values for Irumbupalam watershed. There were differences in terms of soil physico- chemical properties in watersheds between pre-monsoon and monsoon season. The highest values for soil pH (5.87-7.05), C (2.12-6.61%), porosity (41.42-44.95 %), WHC (41.85-72.92 %), SM (9.2- 44.07 %) was recorded in Irumbupalam. Whereas, BD (0.74-1.64 gm cm-3) values were higher in Mayiladumpara than Irumbupalam. Canonical correspondence analysis (CCA) showed a complex interrelationship amongst species clustering, site and soil properties. 118 Mean annual precipitation for both watersheds were recorded. Stream flow measurements were taken monthly for stream depth and stream velocity using float method. Groundwater levels observations was taken monthly from selected wells. Water quality parameter was assessed monthly from upstream, mid-stream and downstream points for both watersheds. Mean rainfall for Irumbupalam and Mayiladumpara for the period (2017-21) was 457 mm and 514.8 mm respectively in the pre-monsoon season, and 1555.5 mm and 1567.7 mm in the monsoon season. Mayiladumpara's monthly streamflow was always higher than Irumbupalam. The pre-monsoon water yield of well was higher in Irumbupalam as compared to Mayiladumpara. The Irumbupalam watershed always had a higher water table than the Mayiladumpara watershed. Stream water temperature (WT), total dissolved solids (TDS), electrical conductivity (EC), turbidity, nitrate (NO3- ) were significantly (p<0.05) higher in Mayiladumpara Irumbupalam. In contrast, dissolved oxygen (DO) and pH of water was significantly higher (p<0.05) in the Irumbupalam. Seasonal variation was observed in the physico-chemical properties of stream water both in watersheds over the study period of eight months. Pearson correlation coefficient revealed that canopy closure was significantly related to some hydrological parameters. Canopy closure was significantly correlated with four water physico-chemical parameters (p<0.05) viz., dissolved oxygen (DO), temperature, electrical conductivity (EC), (NO3-). This indicated that canopy closure is related to water quality. Canopy cover was positively correlated (p<0.05) with DO and negatively correlated with nitrate (NO3- ) (p<0.05). Quantitative as well as qualitative hydrological differences was observed between these watersheds. The physico-chemical parameters of stream water like Dissolved oxygen, Electrical conductivity, Water temperature, Nitrate was found to be influenced by canopy closure of watersheds. The Canopy closure was significantly and positively correlated with soil water holding capacity, soil moisture and soil organic carbon. Soil water holding capacity was found to be significantly and positively correlated with soil porosity, soil moisture soil
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    Analysis of urban microclimates (UMCs) in Thrissur corporation using micro meteorological measurements and remote sensing data
    (Department of Natural Resource Management, College of Forestry,Vellanikkara, 2022-10-12) Mamatha, N A; Gopakumar, S
    Global urban population is increasing at an alarming rate. Unplanned and inadequately managed urbanization has profound effects on microclimate. The unplanned urbanization could transform cities and townships into urban heat islands (UHI) one of the most evident climatic modifications in urbanized areas. The increased heat in the cities affect the environment and the thermal comfort of organisms. Understanding the urban climate is very necessary to make the cities sustainable. The objective of this study is to investigate and analyse the urban microclimates in Thrissur Corporation limits and to understand their linkages with urban greenery. This study will also examine and analyse the perceptions of urban residents in the study locations about different aspects of climate change. The LULC map of Thrissur Corporation was prepared based on NRC guidelines in ArcGIS using Landsat 8 satellite data acquired from Earth Explorer. Three urban LULC class were selected to take the in-situ temperature measurement. Ambient air temperature and relative humidity were measured during the study period in morning 7.30 am and afternoon 2.30pm, the data is further used to assessing urban heat island intensity. Highest temperature was recorded from LULC urban compact, that constitute the commercial center of the city, where the region occupied by highly dense buildings, dense population, heavy traffic, pavement and other impervious structures. The temperature recorded from other urban LULC classes such as urban_sparse and urban- _vegetation is comparatively low. The least temperature was recorded from urban_vegetation. It was noted that temperature difference between LULC classes such as urban_compact, urban_sparse and urban_vegetation is prominent during afternoon compared to morning air temperature. The urban heat island intensity ranging between 0ºC -5.53ºC was observed in LULC class urban_compact. Land surface temperature (LST) and normalized difference vegetation index (NDVI) of various LULC classes in Thrissur corporation was estimated and it was found that the LST is maximum in the LULC urban_compact, where the NDVI values are minimum. Whereas the LST is minimum in the LULC cropland_paddy where the NDVI is maximum. Among the three urban classes, viz. the urban_compact, urban_sparse and urban_vegetated the minimum LST was estimated in the LULC urban_vegetated. To understand the linkage between microclimate and urban greenery correlation test was done between the LST and NDVI values estimated in various urban LULC classes. A strong negative correlation was observed in LULC urban_vegetated (-0.35). The correlation coefficient estimated in urban_sparse and urban_compact is - 0.46 and -0.41 respectively. A perception study was done among 30 people residing in urban area. The way people think about climate change is crucial to developing strategies to address the problem. Among the respondents, majority (80%) have the opinion that the human interventions, predominantly deforestation are the major cause of climate change. On the other hand, 20 % of the respondents are not sure whether human interventions only causes climate change or any natural causes are also there. Chi-square test was done to find the association of respondent’s age and gender with their perception on various aspects of climate change, and no association was found between the respondents age and gender with their perception on climate change. From the study it was understood that the UHI has been developed in the core of Thrissur muncipal corporation belongs to LULC class urban_compact that includes places like East fort, High road and North bus stand. The study also observed the role of urban vegetation in mitigating the urbanization induced climatic modification. However a more focused study considering extra parameter such as air quality , wind speed and wind direction etc will give a better understanding of UMC. In the wake of rapid urbanization UMC study would be helpful in modelling cities for sustainable development.
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    Floristic and edaphic attributes of a shola forest ecosystem in Mankulam forest division Kerala
    (Department of Natural Resource Management, College of Forestry, Vellanikkara, 2020) Abin M Thadathil; Gopakumar, S