Juncus is a plant species that prevents salt build up and the oxygen deprivation in the soil. When it is removed from a plot, the region could support fewer than 50% or even fewer plant species. What Can Juncus be referred to as and what is the population interaction between it and other species called?

 

Any species whose removal causes loss of many others is a key stone species. Since only fewer than 50% plant species are found in the region without Juncus, it is a classic example like Pisaster. Since Juncus itself derives no benefit or remains neutral while other plant species are benefitted, it is commensalism.