Measurement and Monitoring of Biodiversity
Pilot-Scale Measurements
Pilot-scale measurements of biodiversity were carried out in the past using different indices like species richness, the Simpson index and the Shannon-Wiener index (Singh 2002). Among them, species richness is the simplest measure of species diversity. This is done by counting the number of species in a plot or a community. The Simpson and Shannon-Wiener indices are measures that account for richness and allocation of individuals among species. Data on both number of species and number of individuals of each species are needed to calculate these indices (Singh and Kushwaha 2008).
GIS System – A Conservation Tool
Large area coverage of satellite imagery is a new tool for biodiversity assessment (Fuller et al. 1998, Kushwaha et al. 2000, Nagendra and Gadgil 1999). Vegetation-type maps generated from satellite imagery are the first important inputs for a two-stage biodiversity inventory at landscape level (Roy and Tomar 2000; Behera et al. 2006).
The forestry and ecology division of Indian Institute of Remote Sensing, Dehradun, developed a methodology for rapid assessment of biodiversity, encompassing large natural vegetation areas in India using a three-pronged approach (Singh and Kushwaha 2008). The technique makes use of satellite imagery to generate homogeneous vegetation strata and landscape analysis. Landscape parameters like fragmentation, patchiness (Romme 1982), porosity (Forman and Godron 1986), interspersion (Lyon 1983), juxtaposition (Lyon 1983) and proximity of the vegetation patch to biotic disturbance features, such as roads, railways and settlements, are then considered to derive the disturbance index. This is followed by field assessment by the Shannon-Wiener index of diversity in different vegetation strata and evaluation of the vegetation community for its uniqueness and determination of its biodiversity value following Belal and Springuel (1996).
The approach takes into account the terrain complexity, which plays an important role in biodiversity development. The final output, the biological richness is calculated as a function of disturbance index, terrain complexity, biodiversity value, species richness and ecosystem uniqueness. The non-spatial field data are converted into spatial data in the geographic information system (G.I.S.) domain, by assigning values ranging from 1 tolO. The resultant output is scaled to four classes like very high richness, high richness, medium richness and low richness, representing plant richness across the district, state or region. Sampling of biodiversity saves considerable time and cost otherwise needed for such an inventory using ground-based methods alone. A Windows-based software module of the ARC/INFO, BioCAP was developed to aid the landscape analysis (Anonymous 2002; Singh and Kushwaha 2008).
This G.I.S. methodology, developed in 1998, was field tested extensively for biological richness assessment in North-East India (262,179 km2), western Himalayas (339,575 km2), Western Ghats (260,962 km2) and the Andaman-Nicobar Islands (8249 km2) between 1999 and 2001. It provides an enormous quantity of maps and tabular data. During phases 1 and 2 of this project, more than 10,000 plots were sampled and a detailed species database was created (Anonymous 2002; Singh and Kushwaha 2008).
Application of G.I.S. technology in predictive mapping was recently attempted by Bhandari et al. (2020). The population of Rhododendron arboreum Sm. is shrinking in the middle Himalayas due to low seed viability, poor regeneration, habitat fragmentation, habitat distortion and species invasion. The authors attempted to predict R. arboreum distribution in Uttarakhand using the MaxEnt model. The MaxEnt software is particularly popular in species distribution and environmental niche modeling, with over 1000 applications published since 2006 (Phillips et al. 2006; Merow et al. 2013).
A total of 1077 geospatial data was recorded and 300 well-distributed geo-coordinates were used to predict and estimate the distribution. The remaining data were used to validate the model. The MaxEnt model furnished an A.U.C. curve with an accurate and significant value of 0.886 ± 0.023. Bioclimatic variables like temperature seasonality, annual temperature range, altitude, annual precipitation and precipitation seasonality significantly contributed to the prediction of the distribution using the Jackknife test. In the total geographical area of 617.48 km2 under R. arboreum distribution as shown by Landsat 8-generated map, 167.48 km2 were found to be very dense, 320.75 km2 were moderately dense and 129.25 km2 were open. This study shows that satellite- based mapping and model-based prediction of plant species are of great importance to conservation biologists and foresters for species conservation, management and sustainable utilization (Bhandari et al. 2020).
Mapping of Plant Distribution
Understanding the natural distribution and eco-climatic limits of the fast-disappearing taxa can help conservation biologists to formulate strategies for their conservation (Ganeshaiah and Uma Shaankar 1998). With the help of data on distribution patterns and availability of the species, the causes for their reduction in number and rarity can be discovered. Systematic mapping of the occurrence of the species can also help identify regions where conservation has to be initiated. Such maps provide information on the extent of protection required and how effectively it could be carried out (Ved et al. 1998).
The process of developing the maps began with prioritization of wild medicinal plants of southern India, based on data related to their trade. This included volume, value and plant parts or products in trade. Endemism and reported rarity were also considered. A short list of nearly 300 prioritized species was finalized and data on them were collected from the published literature, herbarium records and M.P.C.A. data (Ved et al. 1998).
The survey of India has 1:1 million scale digital maps of state boundaries, rail and road networks, rivers and lakes of the country. Based on such maps, distribution maps were generated using Maplnfo Professional vl.O software. The presence of the species was indicated in the distribution maps, using black, red and blue flags. Black flags represented the herbarium specimens collected from the 22 herbaria visited in connection with the study. Red flags indicated collections from M.P.C.A. network. Locations mentioned in the literature were indicated by blue flags. Using these databases, three types of maps were developed for 60 species of medicinal plants (Ved et al. 1998).
Global and Indian Distribution Maps
Country-level occurrence of a species was depicted in the world map, included as inset in the Indian distribution map. State-level presence of the species was shown on the Indian map. In the case of endemic species with very restricted distribution, like Janakia arayalpathra J. Joseph & V. Chandrasekaran and Pterocarpus santalinus Linn, f., the districts of occurrence were marked on the Indian map. Indian distribution maps were based on data compiled from published floras of the respective states. The maps thus generated serve as ready-reckoner for information on the distribution of particular plant species in the country and neighboring countries (Ved et al. 1998).
Regional Distribution Maps
Maps were prepared for southern India, covering Kerala, Karnataka and Tamil Nadu. They show the district-level occurrence of the species, based on literature survey and recorded collections in herbaria. From a survey of the species mapped, it is observed that most of them occur in the Western Ghats biogeographic zone, which is a major evergreen and deciduous forest region of India, with great biological diversity (Ved et al. 1998).
Eco-Distribution Maps
These maps were generated by superimposing layers of altitude range and rainfall range over the geographical distribution of the species. Such superimposing of altitude and rainfall layers on the distribution maps provides valuable information on the ecological factors that influence the natural occurrence of the species in question (Ved et al. 1998).
Eco-distribution maps are attempted for mapping distribution, occurrence and population of critical species of conservation concern, like Saraca asoca and Coscinium fenestratum. This is not a one-time effort but a continuous upgradation process, based on research and botanical field experience. Incorporating information on precise geographical locations from literature, herbaria and field, correlated with ecological parameters like altitude range, rainfall range and soil type provides an understanding of the pattern of natural distribution of the species. F.R.L.H.T. has created such eco-distribution maps for 450 rare, endemic and threatened species. For educating the society on medicinal plants, 2000 geo-maps for threatened and traded species, prioritized from different bio- geographical regions of India have been created and disseminated as the Digital Atlas of Medicinal Plants, under the Center of Excellence program of Ministry of Environment, Forest and Climate Change. This activity has widened the distribution database of the Indian Medicinal Plant Database ofF.R.L.H.T.-T.D.U.
Sustainable Harvesting
Destructive collection practices are one of the major factors influencing the depletion of plant resources in the wild. Lack of awareness of good collection practices, growing industrial demand for the wild resources, weak guidelines and monitoring mechanisms for wild resource collection and management, competition among the local collectors, non-availability of better prices or incentives for primary collectors and an insufficient policy environment are some of the reasons for destructive collection. Unscientific collections from the wild had led to the threat of species extinction and inflicted severe genetic impoverishment among the wild populations. Sustainable harvesting can improve the livelihoods of people by ensuring a continued supply of biomass through supplementary income and employment (Leaman 2006).
The simplest definition of sustainable harvesting is “the use of plant resources at the levels of harvesting in such a way that the plants are able to continue to supply indefinitely” (Wong et al. 2001). It places an emphasis on maintenance of the population of the species in the wild, irrespective of high demand from across the globe. It is important to conserve the populations of many commercially exploited species in the wild, which face the threat of extinction on the grounds of cultural, ecological and commercial pressures.
Good collection practices or sustainable collection practices are the method of extraction of non-timber forest produce (N.T.F.P.)/medicinal plants or wild resources from the forest areas without causing any damage to their reproduction, while also avoiding damages to their associates. Applying sustainable collection practices in the wild is significant in conservation of resources and fulfilling the needs of forest-dependent communities and other stakeholders, who directly or indirectly benefit from the harvesting of N.T.F.Rs including medicinal plants (Anonymous 2009b).
Success Story
Terminalia chebula Retz.
Terminalia chebula, commonly known as myrobalan, is a deciduous tree, fruits of which have high medicinal value. Apart from this, the fruits of chebula are used in the tanning industry (Auad et al. 2020). In India, more than 10,000 M.T./year is traded. Due to the high demand for these fruits in the herbal as well as tanning industries, the fruits are collected following destructive harvesting methods such as lopping the branches and plucking immature fruits. This results in increased mortality of the trees and decreased regeneration, thereby lowering the fruit yield year after year. Regeneration in Terminalia chebula is also difficult, as the percentage of seed germination is very low. As it is a tree species, fruiting starts at the age of 10-15 years (Bawa 1974).
A pilot project was undertaken in the state of Karnataka to study the quantity of fruits available for collection, development of sustainable harvesting technique and marketing of the collected fruits (Anonymous 2012). The study area was mapped at the onset of the study for understanding the resource availability. Later traditional collection practices were documented. By merging traditional collection practices with modern scientific techniques, sustainable harvesting techniques were developed for collection of the fruits. The sustainable harvesting techniques emphasized collection of 80% mature or fallen fruits. During the process of drying, it was observed that the fruits were turning black. This deteriorates the quality of the fruits and the collector gets lower price in the market. Training sessions were organized to orient the collectors on sustainable and efficient post-harvesting techniques. The intervention made to dry the fruits on a rock or concrete platform helped to retain the golden colour of the fruits, thereby ensuring their quality.
A market survey was undertaken to determine marketing and pricing of the fruits. Before the project intervention, local traders were purchasing at Rs. 5-6 for a kilogram (kg) of fruits. After implementation of sustainable harvesting and post- harvesting techniques such as drying on the rock and grading the fruits based on size and colour, the fruits were directly marketed to an herbal industry in Kerala through the Forest Development Agency, which is a government enterprise, for collection and marketing of N.T.F.P. and medicinal plants. After deducting the expenditure on transportation and other administrative costs, each collector received Rs. 10.35 per kg of fruit. This study demonstrated >75 % price appreciation by adopting sustainable harvesting and post-harvesting methods (Deepa et al. 2019).
