Ornithochory

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The Ornithochor Spreading Bird Cherry ( Prunus avium )

The ornithochory ( old Greek ὄρνῑθ- [ornith-], stem of ὄρνις [ornis]: "bird" - and χωρίς [choris]: "separated, separate" = bird spreading ) is a spreading mechanism in which birds play the role of spreading the diaspores take over.

Adjustments

Similar to animal pollination , the spread of animals has often led to a coevolution between plant and spreader, whereby the specializations on each other are usually less strong, since several mechanisms of spread are often realized in parallel ( polychory ). Nevertheless, some common features can be identified. Since birds have a pronounced sense of sight, the ( generative ) diaspores (these can be seeds, fruits, collective fruits or fruit clusters, see below) are often red, yellow or shiny black, thus forming a strong color contrast to the surroundings. The odor of the diaspores, however, is usually less pronounced. In addition, they usually remain on the stem axis when the seeds are ripe , are soft-skinned and small to medium-sized.

Ecological importance

Birds are very important for seed dispersal . In Central Europe alone, 186 wood plant species were identified whose diaspores are ornithochoric. Many birds contribute to this by hiding diaspores (especially blue jays and pine jays ) as stocks, but not using all of the depots for food ( hiding spread ). This is the case with oak , beech , hazel species and Swiss stone pine , among others . The birds mentioned can justify often entire tree populations in this way, in the forestry are called Hähersaaten. The greater part is certainly spread through endochoria (digestive expansion).

The (endo-) ornithochoric spread plays a major role, especially when repopulating gaps in settlement caused by disturbances (fires, floods, volcanic eruptions, etc.). The dispersal units quickly reach unpopulated places with the bird droppings. This means that these plant species, in addition to the anemochorous species, often belong to the pioneer plants and thus form the so-called initial stage of succession .

Also epiphytes (such as the. Mistletoe ) are usually ornithochor, their seeds are brought by the birds with their droppings directly to the sites to which they have adapted: high branching points by trees.

In the case of mosses in particular , the spread through the use of plant parts as nesting material plays a greater role.

Examples

Examples of ornithochore species that are endochorically spread are:

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