Question

How might three species occupying the same distribution and competing for the same resource be unaffected by indirect facilitation?

What is the most important condition in order for indirect facilitation to occur in riparian communities? Based on your answer, how might the environment shape the frequency at which indirect facilitation occurs in this community?

Answer 1

Indirect facilitation is a mechanism by which three or more species in an area interact with each other. In Indirect facilitation, there is indirect positive effect of one species on another, through the suppression of a shared competitor. There is also direct competitive effect of one species on another. This suppression of the shared competitor should be stronger than the direct competitive effect.

Facilitation is the ubiquotous driver of boidiversity. It has direct and indirect mechanisms . The increase in a diversity results directly or indirectly from the modifications of biotic and abiotic conditions caused by any and all species’ presence. The ability of facilitative mechanisms to modify a site’s conditions created by the environment and by competition, allowes the species diversity to change. In facilitative mechanisms Plants ameliorate stressful conditions for other plants.

Riparian community is Plant habitats and communities along the river margins and banks.

Conditions in reprian communities are environmental stresses, including abiotic resource stress (e.g., water limitation), abiotic non-resource stress (e.g., excessive solar insolation) and biotic stress from herbivores.

Facilitation vary along environmental gradients, There is competition dominating in communities of low‐abiotic stress, while facilitation increases in importance with high abiotic stress .

Only few keystone species provide important facilitative services to many facilitated species under stressful conditions, while under less stressful conditions facilitation may be of lower intensity but provided by a larger number of species.Facilitation is lost under environmental conditions that are favourable to plant growth.