Here is your Essay on the Important Characteristics of Niche for School and College Students!
The niche space is usually measured in terms of one to several variables, such as utilization of space, height of feeding or nesting above ground, position in canopy, size of food, and morphological differences. Organisms have restricted areas of the vertical profile in which they forage. For example, warblers are numerous in the evergreen-deciduous forest ecotone of Eastern North America because they nest and feed in so many diverse niches (Kendeigh, 1945; Mac Arthur, 1958):
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1. Blackburnian warbler: Top level of evergreen trees.
2. Black-throated green warbler: Middle level of evergreen trees.
3. Magnolia warbler: Low level of evergreen trees.
4. Redstart: Secondary deciduous growth.
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5. Black and white warbler: Tree trunks.
6. Black-throated blue warbler: Shaded shrubs.
7. Chestnut-sided warbler: Sunlit shrubs.
8. Canada warbler: Wet shaded ground.
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9. Yellowthroat: Wet sunlit area.
10. Ovenbird: Dry shaded ground.
11. Nash Ville warbler: Dry sunlit ground.
12. Louisiana water thrush: Stream margin.
13. Northern water thrush: Bog forest.
A similar division exists among the bird titmice, Paridae, of Europe (Lack, 1971). Such a division of feeding space may even exist between sexes of same species. The male red-eyed vireo (an American singing bird called greenlet), for example, picks up its insectivorous food in the upper canopy, the female in the lower canopy, with only about a 35 per cent overlap in the feeding area between the two (Williamson, 1971).
Although similar foods may be utilized, each secures the insects from different levels. Similar sexual differences in foraging area exist between males and females of the woodpeckers. Even niches may be separated by the size of food, dictated in birds, perhaps by bill-size (Lack, 1971). Such morphological differences influencing food procurement may exist either between two species or between the sexes of a given species.
For example, two African birds, the greater flamingo (Phoenicopterns antiguorum) and the lesser flamingo (Phoeniconaias minor) share same pond but exploit different niches for food. Here the fine platelets in the bill of the lesser flamingo restrict its diet largely to microscopic blue-green algae, whereas the coarser filter structure in the bill of the greater flamingo allows it to ingest larger food particles like small animals, as tiny crustaceans and mud-dwelling insect larvae.
Similarly a pronounced sexual difference in bill-size exists between some male and female woodpeckers (Dendrocopus arizonae). Differences in bill-length are correlated with differences in foraging behaviour. The male seeks food on the trunk, the female on the branches (Lignon, 1968).
Further, most niche measurements involve plots along at least two axes; the resulting graph covers a certain area along an axis called niche width. The wider the niche, the more generalized a species is considered to be. A species with a narrow niche is considered more specialized. This hypothesis has led to the suggestion that organisms with wide niches show more variability in environmental tolerance or food size, in behaviour or in some applicable morphological measurement such as bill-size.
Certain islands have a number of empty niches (Boughey 1971). This term is used to show that the habitats of the island ecosystem include a number of resources not as yet being fully exploited by the island communities.