Abstract:
:Explaining the maintenance of tropical forest diversity under the countervailing forces of drift and competition poses a major challenge to ecological theory. Janzen-Connell effects, in which host-specific natural enemies restrict the recruitment of juveniles near conspecific adults, provide a potential mechanism. Janzen-Connell is strongly supported empirically, but existing theory does not address the stable coexistence of hundreds of species. Here we use high-performance computing and analytical models to demonstrate that tropical forest diversity can be maintained nearly indefinitely in a prolonged state of transient dynamics due to distance-responsive natural enemies. Further, we show that Janzen-Connell effects lead to community regulation of diversity by imposing a diversity-dependent cost to commonness and benefit to rarity. The resulting species-area and rank-abundance relationships are consistent with empirical results. Diversity maintenance over long time spans does not require dispersal from an external metacommunity, speciation, or resource niche partitioning, only a small zone around conspecific adults in which saplings fail to recruit. We conclude that the Janzen-Connell mechanism can explain the maintenance of tropical tree diversity while not precluding the operation of other niche-based mechanisms such as resource partitioning.
journal_name
Proc Natl Acad Sci U S Aauthors
Levi T,Barfield M,Barrantes S,Sullivan C,Holt RD,Terborgh Jdoi
10.1073/pnas.1813211116subject
Has Abstractpub_date
2019-01-08 00:00:00pages
581-586issue
2eissn
0027-8424issn
1091-6490pii
1813211116journal_volume
116pub_type
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