| Abstract: |
| Competition between macroalgae and corals for occupying the available space in sea bed is an important ecological process underlying coral-reef dynamics. Several benthic macroalgae species produce allelopathic chemical compounds that hinder the settlement and survival of coral larvae. Toxic macroalgae species damage coral tissues when in contact by transferring hydrophobic allelochemicals present on macroalgal surfaces. This leads to the reduction in fecundity of corals and even coral mortality. Also, the release of allelochemicals by toxic-macroalgae influences the microbes associated with corals by transmitting pathogens. We investigate coral-macroalgal phase shift in presence of macroalgal allelopathy and microbial infection on corals under the assumption that the transmission of infection occurs through both contagious and non-contagious pathways. We found that the system is capable of exhibiting the existence of two stable configurations of the community under the same environmental conditions by allowing saddle-node bifurcations that involves in creation and destruction of fixed points and associated hysteresis effect. It is observed that in presence of low coral recruitment rate on algal turf and reduction in herbivory, the system exhibits hysteresis through a saddle-node bifurcation and a transcritical bifurcation. |
|