Download Niche

Prof. Dr. Asrar M. Khan/ Dr. M. Nadeem
Hassan
Habitat & Niche
Habitat & Niche
• Habitats are the places plants and animals normally live.
• The habitat provides factors necessary for survival of
individuals and populations.
• A niche is the role and position of a species in nature.
• In short, every aspect of a plant or animal's existence
can determine its niche.
• Another way of looking at it is that a niche is basically an
organism's "job" in nature.
• Obviously, the concepts of "niche" and "habitat" overlap,
but with "niche" focusing more on the animal's "job,"
while "habitat" focuses more on what corner of nature
the organism occupies.
Habitat
• Types of environment in which a population or species
regularly lives.
• Environment includes biotic and abiotic factors e.g.
forests, meadows, pasture, coniferous forest etc.
• The habitat provides factors necessary for survival of
individuals and populations.
• Examples of important habitat features for animals
include cover (i.e., protection from weather extremes and
predators), nesting and birthing sites, feeding sites, and
hibernation sites.
Habitat
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Habitat can be divided into layers or zones/ Microhabitat
Forest canopy: leaves & branches
Shrub layer: leaves, branches, trucks
Herb layer:
leaves, stems, mosses, ferns
Litter:
dead fallen leaves, logs
Soil
top soil, subsoil
Occupying Species: A species may occupy a specific
part of a microhabitat with some limitations
Niche
• Niche
• The concept of ecological niche is useful in explaining how
seemingly similar species can coexist in the same biotic community.
Ecological niche is the particular combination of biotic and abiotic
factors required by a species to live in any one location. Niche is
sometimes thought of as the "role" an organism fills in the
ecosystem. The term niche has been used by ecologists to refer to habitat,
food, reproductive requirements, and physical and chemical factors related
to a species survival.
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Species’ or population’ role in its community
Characteristics of a niche:
Habitat & microhabitat (space occupied)
Food “spectrum” essential nutrients
Niche
• Reproductive requirements; nutrition, nest/den sites
• Seasonality: when are resources required or used
• Climate requirement: Humidity, rainfall, sunlight
• Two kinds of niche
• Fundamental niche
• All of the potential niche component components for a
given species if there were no competition for those
resources.
• Realized niche
• What the population actually gets while in competition
with other species.
Niche
• No two species can occupy the same niche at the same
time without tough competition – one species have to
give in.
• Vacant niche; a niche that is not occupied by a species
• Competition:
• Organisms always compete for resource; space, food,
mates/partner etc.
• Intraspecies competition: competition between
organism of a different species e.g. bats and bird
compete for same insects.
Niche
• Interspecies competition between the individuals of the
same species
• Competition drives natural selection
• Co-evaluation: in a natural setting, species continuously
compete and evolve with each other and the
evolutionary change or one is based on the evolutionary
change of another. Humans and our parasites
• Invasive species are successful because have not co-evolved with
the native species and can take their niche. New diseases, Invasive
plants, invasive insects etc.
Niche
• Reducing competition:
• Different species often divide resources to reduce
Intraspecies competition
• Different species of birds will occupy different areas
within the canopy of tree to reduce competition from
other species.