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Environment ManagementConcepts of Ecology

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Ecology DefinitionsThe wordEcologycomes from the Greek oikosmeaning house

or place to live. Taken literally, Ecology refers to the study oforganisms in their natural habitat.

DEFINITIONS:

Living Organism: Any form of life, includes all flora and fauna.Ecology deals with how individuals are affected by (and how

they affect) the environment.Habitat: Major habitats are Land (terrestrial, incl. subterranean),

Water (both freshwater and marine), andAir (Biosphere, incl.trees and plants) where birds, insects, mammals, reptiles andamphibians (incl. Micro-organisms) live.

Community: Populations of different plants and animals living andinteracting with one another in an area. The composition andstructure of communities and natural resources affected bythem is not constant. They are continuously changing due tointeractions and disturbances caused by climactic and geologicalevents, as well as by human activities.

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Definitions (contd.)Ecosystem: is the fundamental concept of ecology, which emphasizes

relationships and inter-dependence of communities making up theecosystem.

Remarkable aspect is self-maintenance, self-regulation and naturalstate ofequilibrium present within the ecosystem.

Human activities tend to disruptthe natural functioning andmechanisms and sometimes create an imbalance.

Our country is blessed with a variety of ecosystems like

The Mountains of the Himalayas, Nilgiris, etc.;

Cold deserts (Ladakh) and Hot deserts (Thar, Rajasthan);

The Indo-Gangetic plain very fertile and highly productive;

Areas with very low rainfall (Sivakasi, Kalahandi), and very highrainfall (Mawsynram, Meghalaya);

Estuarine deltas (Sunderbans) and Wetlands (Chilika, Orissa), etc.

Each of these ecosystems supports a large variety oflife-forms.Therefore, the dynamics of each of these ecosystems need to be

properly understood.

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Sunderbans [Sanctuary Asia, Oct.2004]THE EARTHS LARGEST ESTUARINE MANGROVE DELTA

This dynamic ecosystem now holds the largest single tiger population in theworld, as well as a host of other mammals, avians, reptiles, marine fauna andinvertebrates. The dense mangrove forests of the Sunderbans sustain anincredible diversity ofterrestrial and marine life, and are a direct means oflivelihood for lakhs of people. The unique feature of mangroves is that they

thrive in salt/brackish water,

and breathe throughpneumatophores (aerialroots) which protrudethrough the mud. Mangrovesact as biological filters andare of immense importanceto coastal flora and fauna.

The Sunderbans, spread

over 10,000 sq km in India andBangladesh, is a vast andremote land mass, criss-crossedwith hundreds of rivers, creeksand tidal channels.

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Biological Clock Flamingos

Migratory birds/animals sometimes cross half the globe to reach their annual breedinggrounds, guided by only their instinctand their biological clock (eg, Siberian cranes,Whales, etc). More than 20,000 Flamingos migrate every year to feed in the SewriandUran mudflats near Mumbai, from their breeding grounds in the Rann of Kutch.However, of late there seem to be a big drop in their numbers, either due to urban andindustrial pollution or active work on the Sewri-Nhava Transharbour link, which is a

cause for major concern.

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Limiting factor - VulturesScience & the Environment, 18/02/04

Vultures, Dying faster than the Dodo: Asian

vulture populations collapse due to unregulateduse of Veterinary medicine.by Edward Teague et@shoppp.comThe common vulture is said to be the most abundant

raptorin the world, with a global population exceeding 10

million in the early 1990's. Vultures have an importantecological role in the Asian environment, where they have

been relied upon for millennia to clean up and removedead livestock and even human corpses,says PeregrineFund biologist, Munir Virani.

The first signs of a massive population crash of the species in India was first noticed and

reported from the Keoladeo National Park near the North Indian town ofBharatpurwhere

nesting pairs declined from 353 in 1987/88 to 20 in 1998/99 with none recorded in

1999/00 and 2000/01 and only one bird seen in 1999/2000.

In 1989, Dr Vibu Prakash of the Bombay Natural History Society had observed sick birds,

listless and evidently unwell, inexplicably dying. He found, after autopsy, evidence of

kidney degeneration which he attributed to some unknown viral infection.

However, this hypothesis could not be scientifically substantiated. Further research on a

global level led to the conclusion that residues of the commonly used veterinary product

diclofenacin dead livestock, eaten by vultures are directly responsible for the population

collapse, with important economic, cultural and human health consequences.

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Definitions (contd.)

Limiting factor: Single factor that limits the growth, abundance anddistribution of the population of a particular organism in an ecosystem.

Any factor in short-supply or over-supply can become a limiting factor,eg. Temperature, light, water, etc.

Carrying capacity: Maximum population of a particular species that a givenhabitat can supportover a given period of time. Overloading due toexcessive population leads to environment getting exhausted.

CASE STUDY: Panthers of Sanjay Gandhi National Park [TOI, 7.3.2002]

Bittu Sahgal, Editor ofSanctuary magazine, said: Most panther cubs diebefore adulthood because their mothers cannot find enough food. Thisis natures way ofregulating numbers of predators. In SGNP, peopleliving on the periphery and in settlements inside generate huge

quantities ofedible garbage, which results in a large number of dogs,who are easy prey or panthers. This results in more cubs surviving toadulthood..

The panther attacks are thus directly related to the human encroachmentsinto the animals habitat, as also the stray dog population.Unfortunately, the panther soon discovers that man is the easiest prey.