Environmental Biology III: Biodiversity and its Conservation — Types, Values and Threats, Hotspots, Measures of Diversity, In Situ, Ex Situ and In Vitro Conservation, Protected Areas and Sacred Groves, Gene Pools, Biopiracy and Bioprospecting, Restoration Ecology, Threatened Species of India, and Industrial Ecology

Norman Myers proposed the idea in 1988, identifying ten tropical forest regions where exceptional concentrations of endemic species faced exceptional loss of habitat, so that conservation money would save the most species per unit spent. Conservation International formalised the criteria: a region qualifies if it has at least 1,500 species of endemic vascular plants (more than 0.5% of the world's total) and has lost at least 70% of its original natural vegetation. There are now 36 hotspots worldwide, the most recent, the North American Coastal Plain, recognised in 2016. Together they cover only about 2.5% of the land surface but hold more than half of the world's endemic plant species.

India is one of the world's seventeen megadiverse countries, with about 2.4% of the world's land area and about 7 to 8% of its recorded species, a richness owed to the meeting of three biogeographic realms, a range of climates from desert to rainforest and from sea level to over 8,000 m, and long isolation of the peninsula.

Species richness, S, is the simplest measure: the number of species present. Because richness rises with sampling effort, Margalef's index corrects for sample size: (S − 1) ÷ ln N, where N is the total number of individuals. Diversity indices combine richness with evenness, the equality of abundances. If pᵢ is the proportion of individuals belonging to species i, the Shannon-Wiener index is H′ = −Σ pᵢ ln pᵢ; it is zero for a single species and rises with both richness and evenness, typically lying between about 1.5 and 3.5 in real communities. Pielou's evenness, J = H′ ÷ ln S, scales it from 0 to 1. Simpson's index, D = Σ pᵢ², is the probability that two individuals drawn at random belong to the same species, so it measures dominance; diversity is reported as 1 − D (the probability that they differ) or as 1/D.

For this community, Simpson's diversity 1 − D = 1 − 0.30 = 0.70 and 1/D ≈ 3.3; Shannon's H′ ≈ 1.28, and evenness J = 1.28 ÷ ln 4 = 1.28 ÷ 1.386 ≈ 0.92. Beta diversity compares sites. The Jaccard coefficient of similarity is c ÷ (a + b − c), where a and b are the species at two sites and c the species they share; the Sørensen coefficient is 2c ÷ (a + b). If one site has 20 species, another 15 and they share 10, Jaccard = 10 ÷ 25 = 0.4 and Sørensen = 20 ÷ 35 ≈ 0.57. Whittaker's beta diversity is γ ÷ mean α − 1.

In situ conservation protects species in their natural habitats, together with the ecological processes and interactions that sustain them, and is the primary strategy. India's protected areas under the Wild Life (Protection) Act 1972 are national parks, where no rights of people are allowed and grazing is prohibited; wildlife sanctuaries, where some rights and activities can be permitted; and, since the 2002 amendment, conservation reserves and community reserves on government and community or private land respectively. Tiger reserves and elephant reserves are overlaid on these. Biosphere reserves, under UNESCO's Man and the Biosphere programme (1971), have a strictly protected core zone, a buffer zone for research, education and limited use, and a transition zone where sustainable development and settlements are encouraged; India's first was the Nilgiri Biosphere Reserve (1986).

Sacred groves are patches of forest protected by local communities because they are dedicated to a deity or ancestral spirit, often for centuries; hunting, felling and even the removal of dead wood may be forbidden. They are refuges for relict species and often protect springs. They are known by regional names: devrai or devrahati in Maharashtra, kavu in Kerala, sarna in Jharkhand, law kyntang in Meghalaya (the Mawphlang grove is famous), orans in Rajasthan and devara kadu in Karnataka. They are an example of community conservation older than any law.

The gene pool is the total of all the genes and their alleles in an interbreeding population; its loss, genetic erosion, occurs when high-yielding uniform varieties replace traditional landraces or when populations shrink. Bioprospecting is the systematic search for genes, compounds and organisms of commercial value, and it is legitimate when the country and communities that supply the resource and knowledge give prior informed consent and share the benefits, as the Nagoya Protocol (2010, in force 2014) requires. Biopiracy is the appropriation of biological resources or traditional knowledge without consent or benefit sharing, often through patents; India successfully challenged a United States patent on the wound-healing use of turmeric, revoked in 1997, and a European patent on a neem-based fungicide, revoked in 2000, largely by showing prior traditional knowledge. Restoration ecology is the science of assisting the recovery of degraded, damaged or destroyed ecosystems towards their historical trajectory, through reforestation, the reclamation of mine land, the rewetting of wetlands and the reintroduction of species; the UN has declared 2021 to 2030 the Decade on Ecosystem Restoration.

The IUCN Red List assigns species to categories on quantitative criteria of population decline, range size, population size and extinction probability: Extinct (EX), Extinct in the Wild (EW), Critically Endangered (CR), Endangered (EN), Vulnerable (VU), Near Threatened (NT), Least Concern (LC), Data Deficient (DD) and Not Evaluated (NE). Only CR, EN and VU together are "threatened". "Rare" was a category in older Red Data Books, meaning small populations not at present endangered, and survives in national lists such as the Red Data Book of Indian Plants compiled by the Botanical Survey of India; the Zoological Survey of India compiles the animal equivalent.

Plants face the same pressures of habitat loss and over-collection, especially medicinal species harvested from the wild, such as kuth (Saussurea costus), listed on Appendix I of CITES, and the red sanders of the Eastern Ghats, prized for its timber and heavily smuggled. The vulture crash is the clearest Indian case of a single pollutant driving species towards extinction: populations of three Gyps species fell by over 95% in little more than a decade after diclofenac, a veterinary painkiller, entered carcasses.

Industrial ecology studies industrial systems as if they were ecosystems, tracing the flows of materials and energy through them and redesigning them so that, as in nature, the wastes of one process become the raw materials of another. The term was popularised by Frosch and Gallopoulos in a Scientific American article of 1989. Its tools include material flow analysis, life-cycle assessment and design for environment, and its practical form is industrial symbiosis. The classic case is Kalundborg in Denmark, where, over several decades and without central planning, a power station, an oil refinery, a pharmaceutical and enzyme plant, a plasterboard factory, a fish farm and the municipality came to exchange steam, cooling water, gypsum from flue-gas desulphurisation, fly ash, sludge and surplus heat. Eco-industrial parks attempt the same by design, and the idea underlies the circular economy.