Ecological facilitation
For example, seed germination and survival in harsh environments is often higher under so-called nurse plants than on open ground.
[1][3] A nurse plant is one with an established canopy, beneath which germination and survival are more likely due to increased shade, soil moisture, and nutrients.
[1][3] The beneficial effects of species on one another are realized in various ways, including refuge from physical stress, predation, and competition, improved resource availability, and transport.
A similar interaction occurs between the red alga Chondrus crispus and the canopy-forming seaweed Fucus in intertidal sites of southern New England, US.
An example of such "whole-community" facilitation is substrate stabilization of cobble beach plant communities in Rhode Island, US, by smooth cordgrass (Spartina alterniflora).
[6] Large beds of cordgrass buffer wave action, thus allowing the establishment and persistence of a community of less disturbance-tolerant annual and perennial plants below the high-water mark.
However, at higher elevations where soil salinity was lower, marsh elder fitness was decreased in the presence of the rush, due to increased competition for resources.
[1][3] Herbivory can also reduce predation of the herbivore, as in the case of the red-ridged clinging crab (Mithrax forceps) along the North Carolina, US, coastline.
[2] The acacia provides nourishment and protection (inside hollow thorns) to the ant in return for defense against herbivores.
Three African bird species (village weaver Ploceus cucullatus, common bulbul Pycnonotus barbatus, and mouse‐brown sunbird Anthreptes gabonicus) regularly feed on the sap flowing from holes made by local wine tappers in oil‐palm trees Elaies guineensis in the Bijagós archipelago, Guinea‐Bissau.
[17] However, the most familiar examples of increased access to resources through facilitation are the mutualistic transfers of nutrients between symbiotic organisms.
This is apparent in whole-community facilitation by a foundation species, such as sediment stabilization in cobble beach plant communities by smooth cordgrass.
[6] A facilitating species may also help drive the progression from one ecosystem type to another, as mesquite apparently does in the grasslands of the Rio Grande Plains.
[19] Other mechanisms such as resource partitioning and sampling effect act in tandem with facilitation to increase biodiversity (observable evidence in plant communities).
