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Habitat and Niche

Concepts of Habitats and Niche

Concept of Habitat

   Habitat is the environment in which a particular organism may live, breed and eventually die. The organism may be either Animal, Plant or Microscopic in nature, while the environment or Physical surroundings provides for its sustainable growth. Organisms may have even multiple habitats based on their physiology and memory. Its commonly practice for Sockeye Salmon to spawn in rivers hundreds of miles inland which is considered their juvenile habitat. However once they reach juvenile maturity, they will venture back out to sea where they will grow to adult maturity and head back to the rivers to spawn and die.

There are 2 main types of Habitats to consider.
  1. Macro habitat (Is the larger habitat surrounding largely mobile organisms. The macrohabitat may cantain the nescessary elements for multiple organisms to survive and reproduce within its environment). In the image below, the Manatee occupies a macrohabitat in which several other organisms are also dependants upon.

  2. Micro habitat (Is the immediate habitat surrounding small organisms. This microhabitat may not contains all the nutrients needed to support the confined organisms, however owing to the physiological nature of the microhabitat, these organisms will continuously remain in this confined environment) - The following example shows the (A) microhabitat of stringy seaweed below the intertidal zones.

Concept of Niche

   Niche is the term used to define the role of the organism within its habitat. By definition the niche role is played by no more than 1 individual species within its ecological environment. It could also refer to the position or status of an organism within a community and ecosystem resulting from its structural adaptation and behavior. It may also be referred to as an Ecological Niche.

There are 2 main types of Niches to consider.
  1. Fundamental Niche (Where the role of the organism is studied under controlled environments without disruptions from predators)
  2. Realized Niche (where the role of the organism is studied in the wild without any human interference)

General Discussions

   When early explorers documented their finding in foreign lands, they never failed to mentioned the unique diversity of animals and trees that they have encountered. Even though they didn't understand biodiversity, they were quite capable of drawing pictures and naming such plants and animals after their own native language. Today we see these ancient drawing in museums and in documentaries as historical evidence to certain species of animals which have now gone extinct. One such species was the Dodo.

    All species occupy either one or more niches in their environment and thus provide a certain type of support for all other dependent species, which in turn are ecological niches themselves. Therefore even if one ecological niche is disrupted, the danger can spread through successive chains disruption the entire ecosystem...

Dodo: A Failure to adapt. (Mauritius Island / Indian Ocean)
Once a species adapts to a particular niche environment, it becomes more prone to extinction if that environment is changed. This statement holds particularly true if the species in question has no natural predators.

When settlers arrived in the Island of Mauritius the Dodo's was hunted to almost extinction. Due to its ecological niche in the environment, the Dodo had lost its flight feathers and thus remained an easy target for hunting. Its also believe that the "Dodo tree" (Tambalacoque) is almost extinct due to the absence of tho Dodo. Stanley Temple believe the Dodo played a significant role in germinating these seeds as the Dodo's stomach acids were able to weaken the Tambalacoque seeds enabling it to germinate. He also reported a significant decline in the Tambalacoque after the demise of the Dodo.

The Dodo is a classic example of niche habitat disaster due to mans interference. As cargo ships gathers, rats, cats, pigs, dogs also contributed to the destruction of their nesting grounds thus systematically eliminating them from their natural habitat.

Ecological Niche. Sword-billed hummingbird (S. America)

Certain species of Hummingbirds have adapted specialized beaks for feeding deep throat flowering plants. Some species of hummingbirds are solely responsible for pollinating certain types of flowering plants within a larger geographical boundary.

This sword-billed hummingbird is the largest hummingbird of all species. Its also the only hummingbird capable of pollinating the Passiflora mixta flower; thereby acquiring a certain niche within its habitat.

If this ecological niche is broken, there would be a decrease in the population of Passiflora mixta as well as other dependent organisms. Sword-billed hummingbirds are also responsible for pollinating flowers over a wider geographical zone. This may also prevent inbreeding of flora. Most species of hummingbirds are completely dependent on certain species of flora for survival, which is commonly known as co-dependencies.
Pitcher Plant. Carnivorous.
Pitcher plants are capable of controlling the insect population within its habitat due to its physiological adaptations. Like all carnivorous plants, they occur in locations where the soil is too poor in minerals or too acidic for most plants to grow. In such cases they have occupied a ecological niche within their habitat.

As Pitchers plants are primarily carnivorous, they obtain their mineral from decomposing insects which are trapped within its large hollow tubular leaf. Special enzymes secreted from the plant either provoke direct digestion of bacterial decomposition of the insects which have fallen into the residue.

Only a few other species of carnivorous plants exists around the world which have uniquely adapted to their own environment causing specific habitat niches where no other plant could occupy.