Materials and Methods
BNP encompasses an area of 260 sq.km, comprising of 13 reserve forests spread over the districts
of Bangalore urban,
Bangalore rural and Ramanagara districts; it was declared as a national park in 1974 (Figure 1).
BNP is located in
the south-east tip of Western Ghats with biological, social, hydrological and ecological
significance and forms a
vital conduit of the animal movement path. Forests in BNP have been aiding Bangalore’s climate and necessities through carbon sequestration, the mitigation of
human-animal
conflicts, the repository of diverse flora and fauna, recreation and pollination services as
well as micro-climate
moderation. BNP is one of the oldest prime habitats of Asian elephants, supporting a population
of 100–150 and a
migratory population of a large number, about 200–300, from the adjoining Tali Reserve Forest
and Cauvery Wildlife
Sanctuary; it acts as a terminal point for Eastern Ghats and Western Ghats. BNP, being part of
the Western Ghats
(one among 35 global biodiversity hotspots), is known for high species diversity, structural
organization, spatial
heterogeneity and adaptation to dry climate, moisture stress and irregular rainfall. The average
temperature ranges
from 22°C to 35°C and the annual monsoon rainfall varies from 625 mm to 1,607 mm, from June to
mid-November, from
south-west and north-east monsoons. The terrain represents undulating land with broken chains of
bolder, strewn
hillocks and hills of rocky outcrop and water courses. The forest types cover moist deciduous
forests, dry deciduous
forests, thorny scrub and grasslands with rich flora and fauna. The cropping pattern of BNP and
its environs (5 km)
is very much a modern system of agriculture due to its proximity with Bangalore. The farmers
grow commercial crops
such as banana, coconut, vegetables, sugarcane, mulberry and various flowers. Streams such as
Suvarnamukhi,
Hebballa, Suddahalla, Jakkanahalla Muthyalammamadu holé, Rayathmala holé and Anthragange halla
are present in
the region which support major crops. Floral diversity includes Cissampelos pareira, Decalepis
hamiltonii,
Cardiospermum halicacabum, Gloriosa superba, Cassia fistula, Wrightia sp., Holarrhena pubescens,
Aegle marmelos,
Shorea roxburghii, Phyllanthus emblica and so on;, they are highly valued medicinal plants,
many of them rare
or endangered and traded in high volumes. A total of 218 plants belonging to 60 families were
recorded during the
survey. Among these, trees (81 species) and herbs (88 species) had the highest number of
species, followed by shrubs
(34 species) and climbers (15 species). About 80 species of birds were recorded during the
survey, which include
migratory birds of winter such as Golden Oriole, Forest Wagtail, Rosy Starling, Booted Warbler,
Greenish Warbler,
Ultramarine Flycatcher, Lesser Spotted Eagle, Pallid Harrier and Wire Tailed Swallow and so on.
The presence of
these bird species highlights rich habitats with supporting niche. The distribution of various
faunal species such
as elephants, tigers, leopards, spotted deer and sloth bears is shown in Figure 2. However, an
increase in
anthropogenic activities with the increase in human habitation and the expansion of agricultural
and horticultural
activities have threatened the survival of these fragile ecosystems. The anthropogenic
activities include the
unsustainable exploitation of forest resources, the encroachment of forests, stone quarrying,
sand mining, domestic
livestock grazing and unplanned urbanization; they have become a major threat to the
conservation of forests and its
resources.
Figure 1. Bannerghatta National Park with 5-km Buffer
vegetation cover using the normalized difference vegetation index (NDVI) as per Equation (1). NDVI, also known as a greenness index, values ranges between −1 to and +1 and helps in delineating vegetation cover.
Figure 2. The Distribution of Various Faunal Species in Bannerghatta National Park
Land Use Land Cover Analysis
Landscape dynamics in the BNP region is assessed with the help of temporal spatial data acquired through space- borne sensors (RS data), ancillary data (collateral data compiled from government agencies) and primary data compiled through field investigations (ground control points and training data—polygons of land uses with attribute information). Figure 3 outlines the protocol followed to analyse land uses from the spatial data. RS data used in the study are Landsat MSS (1973), TM (1989, 1999), Landsat ETM + (2009), downloaded from the public domain (http://landsat.org), IRS p6L4X (2015) (http://nrsc. gov.in) and the online Google Earth portal (http://earth. google.com). Ancillary data were used to assist the interpretation of different land use types from RS data. Topographic maps provided ground control points to rectify remotely sensed data and scanned paper maps (topographic maps) and assigned the UTM (zone 43 N) projection system. The Survey of India (SOI) topographic maps (scale: 1:50000 and 1:250000) and vegetation maps of South India (scale: 1:250000) developed by the French Institute (1986) were digitized to identify various forest cover types and for temporal analyses to understand vegetation changes. Field data (ground control points and training data) were collected with the help of pre-calibrated GPS (global positioning system, Garmin GPS unit). Ground control points were used for the geometric rectification of RS data. The training data were used for the classification of RS data (land use analysis) based on supervised classification approaches through the Gaussian maximum likelihood (GML) algorithm. Land cover analysis was conducted to understand the extent of Land use analyses using remote sensing data involved (a) the generation of false colour composite (FCC) of RS data (bands: green, red and Near Infrared [NIR]). This composite image helped in locating heterogeneous patches in the landscape, (b) the selection of training polygons covering 15 per cent of the study area (polygons are uniformly distributed over the entire study area), (c) loading these training polygon coordinates into the pre-calibrated GPS and (d) the collection of the corresponding attribute data (land use types) for these polygons from the field. GPS helped in locating respective training polygons in the field,
- supplementing this information with Google Earth and
- a total of 60 per cent of the training data were used for classification, while the balance were used for accuracy assessments (Bharath et al., 2013; Congalton, 1991; Jensen, 2005; Ramachandra, Bharath, & Sanna, 2012) by error matrix and kappa statistics (Anderson, Hardy, Roach, & Witmer, 1976; Liu, Frazier, & Kumar, 2007). Land use analysis was conducted using a supervised classification technique based on the GML algorithm with training data (collected from the field using GPS). Gaussian maximum likelihood (GML) is a widely used statistical classification method which assigns a given pixel to a specific class based on conditional probability. The likelihood for a given pixel with a spectral value to be assigned to a class is determined using Bayes’ theorem and the decision rule calculated by natural logarithm or ‘discriminant function’ (Lillesand, Kiefer, & Chipman, 2014). Geographical Resources Analysis Support System (GRASS GIS, http://ces.iisc. ernet.in/grass), a free and open-source software with robust support for processing both vector and raster data, was used to analyse RS data through available multi-temporal ‘ground truth’ information (http://ces.iisc.ernet.in/grass).
Figure 3. Method Followed in the Analysis
Modelling Spatial Patterns of Transitions
Land use analyses provided spatial patterns at the temporal
scale and the Markovian process aided to generate the transition probability map and area matrix based on the probability distribution of the current cell state that was assumed to only depend on the current state (Equations [2] where P(N) is state probability at any time and P(N − 1) is preliminary state probability.
Transition area matrix can be obtained by, and [3]). The land use maps of 1999–2015 were reclassified into five categories for effective visualization as explained in Table 1. The original transition probability matrix (denoted as P) of land use types can be obtained from two
Transition area Matrix P former land use maps. Cellular automata was used to obtain a spatial context and distribution map based on Markov’s transitional probability and area by combining multi- criteria land allocation to predict land cover change over time. The water category was considered a constraint (assuming that this category continues to exist). The transition rules were made considering the possibility of forests transforming to other land uses, agriculture and where Pij is the sum of areas from the ith land use category to the jth category in the years from start point to target simulation periods and n is the number of land use types. The transition area matrix must meet the following conditions (Equations (4) and (5)): i. 0 ≤ Pij ≤ 1 (4) built-up transform forests. The rate of transitions was based on past land use changes and current trends, ascertained through field investigations. Also, the city’s developmental plans of 2015 (available at http://bbmp.gov.in/revised- master-plan) and 2031 (http://www.bmrda.kar.nic.in/rsp_ report.pdf) have been used in the analysis. The proposed