TY - JOUR TI - Positive density dependence acting on mortality can help maintain species-rich communities AU - Aubier, Thomas G A2 - Donoso, David A2 - Weigel, Detlef VL - 9 PY - 2020 DA - 2020/06/18 SP - e57788 C1 - eLife 2020;9:e57788 DO - 10.7554/eLife.57788 UR - https://doi.org/10.7554/eLife.57788 AB - Conspecific negative density dependence is ubiquitous and has long been recognized as an important factor favoring the coexistence of competing species at local scale. By contrast, a positive density-dependent growth rate is thought to favor species exclusion by inhibiting the growth of less competitive species. Yet, such conspecific positive density dependence often reduces extrinsic mortality (e.g. reduced predation), which favors species exclusion in the first place. Here, using a combination of analytical derivations and numerical simulations, I show that this form of positive density dependence can favor the existence of equilibrium points characterized by species coexistence. Those equilibria are not globally stable, but allow the maintenance of species-rich communities in multispecies simulations. Therefore, conspecific positive density dependence does not necessarily favor species exclusion. On the contrary, some forms of conspecific positive density dependence may even help maintain species richness in natural communities. These results should stimulate further investigations into the precise mechanisms underlying density dependence. KW - competition KW - species coexistence KW - species diversity KW - reproductive interference KW - theoretical ecology KW - Allee effect JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -