How a Development Project Destroys Biodiversity

In one line

A project destroys biodiversity in six ways, and only two of them are visible on the site plan.

In exam wording: a development project affects biodiversity by direct loss of habitat under the footprint; by fragmentation, which divides a population into isolated parts; by edge effects, which change the conditions of the habitat that remains; by disturbance from noise, light, traffic and people; by pollution of water, air and soil; and by the induced development that follows access, which is usually the largest effect and is never in the project's own accounts; and the Indian instruments that address them are the Environmental Impact Assessment Notification 2006 made under sections 3 and 5 of the Environment (Protection) Act 1986, section 2 of the Van Adhiniyam 1980, sections 29 and 35 of the Wild Life (Protection) Act 1972, and the Forest Rights Act 2006 for the people affected.

MU's own phrase. She asks for the effects of development projects on biodiversity, and the answer has a physical half and a procedural half.

The six mechanisms

1. Direct loss. The area cleared for the works. It is the only one a project measures accurately, and it is usually the smallest.

2. Fragmentation. A road, canal or transmission line divides a habitat. The total area lost is small; the effect is two populations where there was one, each too small to survive a bad year and each losing genetic variation. The corridor between two tiger reserves is the standard Indian example, and section 38V of the Wild Life (Protection) Act 1972 requires a tiger conservation plan to provide for the ecological needs of the reserve.

3. Edge effects. The boundary of a fragment is not the same as its interior. Light, wind, temperature and humidity change; weeds and invasive species colonise; predators and human access reach further in. A long, thin fragment may be all edge.

4. Disturbance. Noise, artificial light, vehicle movement, dust and the presence of people change behaviour, breeding and feeding, at distances well beyond the footprint.

5. Pollution. Effluent, dust, spoil and runoff. Indian Council for Enviro-Legal Action v. Union of India (1996) 3 SCC 212 is the standing Indian illustration: sludge from chemical industries at Bichhri percolated into the aquifer and rendered the soil unfit for cultivation, and the Court applied the polluter pays principle and directed recovery of the cost of remedial measures.

6. Induced development. A road brings settlements, shops, extraction and encroachment. This is almost always the largest effect and is almost never assessed, because it is caused by third parties rather than by the proponent.

What the law measures, and what it does not