Quantification of anthropogenic disturbances in forest as a function of distance to human habitation - a case study from Peechi - Vazhani wildlife sanctuary

Abstract

A study was conducted in the moist deciduous forest of Peechi- Vazhani Wildlife sanctuary to understand and quantify the impacts of human induced disturbances on forest, based on vegetation, soil and anthropogenic disturbance indicators. Three sites were randomly selected from the sanctuary. Based on distance from these human habitations, the forests at these locations were divided into three strata (0-2 km, 2 -6 km and beyond 6 km). Four samples (each 2500 m2) were selected randomly from each of the strata’s and surveyed for trees, saplings, regeneration, soil and disturbance. Four sub samples of (100 m2 each) in each of the selected samples were enumerated for herbs and shrubs. Various forest health indicators of vegetation, soil and disturbance were studied. Based on these indicators, the study developed Human Disturbance Indicator (HDI) and Soil Quality Index (SQI) to assess/ quantify the impact of human disturbance on forest. The ecological stages of these forests were assessed using Ramakrishnan index of stand quality (RISQ), vegetation composition and structure. This study observed the forests of P-V WLS to be secondary moist deciduous forests. Significant differences were observed between forests near human habitations and those away from it in terms of vegetation structure but not in diversity. Significant differences were observed between strata in terms of number of trees, mean GBH, mean height, canopy gap and LAI. However, differences were observed among the strata in species of diversity of saplings and seedlings. Significant differences were seen between strata in terms of clay fraction, moisture content, bulk density, pH, infiltration rate, available P and SQI. Differences were seen among strata in terms of HDI. However, all these differences were found to be influenced by location effects too. The study concluded that the degradation was influenced by location as well as distance from habitations. The disturbance map and soil quality map was developed using the indexes.