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close this bookBasic Concepts in Environment, Agriculture and Natural Resources Management: An Information Kit (IIRR, 1993, 151 p.)
close this folderIntroduction
View the documentUse of workshop
View the documentWorkshop participants
View the documentSupport staff
View the documentGlossary of commonly used environmental terms
View the documentList of references
close this folderEcological basics
View the documentEcosystem degradation
View the documentHabitat and niche
View the documentThe food chain
View the documentBiological magnification
View the documentNitrogen cycle
View the documentSociety and the carbon-oxygen cycle
View the documentHealth consequences of environmental degradation
View the documentPopulation and the environment
close this folderFreshwater and marine ecosystems
View the documentFreshwater ecosystems
View the documentEstuarine-mudflat ecosystems
View the documentSeagrass ecosystems
View the documentMangrove ecosystems
View the documentCoral reef ecosystems
View the documentHuman intrusions into the water cycle
View the documentDiversity of coastal and marine resources
View the documentPhilippine marine fisheries
View the documentMarine turtles
View the documentMarine food web
View the documentOcean pastures
View the documentThe menace of algal bloom
View the documentRed tide (Dynamics and public health aspects)
close this folderForest ecosystems
View the documentTropical forest -ecosystems
View the documentProtected areas: a tool for biological diversity conservation
View the documentEnvironmental effects of overexploitation for fuelwood in nearshore coastal resources
View the documentBiological diversity: and wildlife conservation
View the documentWildlife trade
close this folderGlobal warming and acid rain
View the documentClimate change and the greenhouse effect
View the documentHow deforestation contributes to the greenhouse effect
View the documentAcid rain
close this folderPollution
View the documentToxic and hazardous wastes
View the documentPollution and long-term effects on the human body
View the documentUrban pollution: The metro Manila environment
View the documentMining operations: environmental effects on soil, water, communities and atmosphere
View the documentPesticides: environmental and health effects
close this folderOthers
View the documentPhilippine commercial energy sources, 1990
View the documentCommon property resources in crisis
View the documentDegradation of the uplands
View the documentLowland degradation
View the documentEnvironmental issues in animal production
View the documentPlant genetic resources
View the documentNatural hazards

Habitat and niche


Habitat and niche

Habitat = address or home of an organism

· The area where an animal lives or its home, usually an ecosystem or an area within an ecosystem.

· Habitat relates mostly to the non-living physical or chemical conditions of the area such as temperature, rainfall, salinity, sunlight, soil and elevation.

· Habitat and the preservation of biodiversity

· Habitat conservation is directly related to species conservation. The protection of habitats is a more systematic and comprehensive way or preserving species. By protecting any given habitat, a host of species will automatically be protected. This is often more useful than trying to preserve a single species. The loss of habitat is the main cause of species loss in the world. For example, the preservation of mangrove habitat protects those plants and animals that are associated with it.

Niche = occupation of an organism in its community

· A species niche is composed of its habitat, plus the biological or living things found the habitat. The living component (plants and animals) of a habitat is called a community.

· Biological factors include location on the food chain (producers, herbivores, carnivores, etc.) predator/prey relationships and reproductive requirements.

· Interrelationships and interactions are important aspects of niche. For example, tall trees provide shade for plants and animals living under it; birds help disperse seeds of certain trees; and, worms help to aerate the soil.

· Temporal activities are also important in understanding niche. Activities which relate to temporal cycles such as day and night, lunar or seasonal cycles help to define the niche of an organism.

Specialized is generalized niches

Specialized niches apply to species which have very well-defined or narrow physical, biological or chemical requirements for survival. If an organism can only be found within very limited or specific conditions, it is considered to have a very specialized niche. The dugong is an example of an animal with a specialized niche. It requires seagrass beds for food and warm, calm waters for rearing its young. Animals such as the dugong with a specialized niche are more susceptible to extinction than animals with a generalized niche.

Generalized niches apply to species which can exist in a broad range of conditions. Humans are the best examples of species with a generalized niche. In the Philippines, as elsewhere, humans live in diverse conditions with an almost infinite variety of interrelationships. Other animals that are considered to have generalized niches are cockroaches, flies and rats.

Competitive exclusion principle

The fact that no two species can occupy the same niche is called the competitive exclusion principle. For example, two different species of Kingfisher may share the same habitat but may feed on different organisms at different times of the day or in different places.

Niche and ecosystems changes

Understanding the niche of species within an ecosystem will provide insights as to what the consequences of change may be. Two of the more common changes are the elimination of a species and the introduction of exotic or foreign species. The removal of a species whether through extinction or habitat loss can have many undesirable effects. This is often seen when pesticides eliminate beneficial as well as harmful insects. The result can be the removal of an important predator of harmful insects and subsequent increases in the pest population. Understanding the niche of the various organisms in a given habitat will help to predict potential effects of change. The introduction of exotic or non-native species can also bring about detrimental effects. If the introduced species is known to be very resilient and competitive and has a generalized niche, it may colonize-large areas to the detriment of native species. The Eurasian Tree Sparrow is an example of this in the Philippines.