Differences among species in seed dispersal and conspecific neighbor effects can interact to influence coexistence

Seed dispersal is a critical mechanism for escaping specialist natural enemies. Despite this, mean dispersal distances can vary by an order of magnitude among plant species in the same community. Here, we develop a theoretical model to explore how interspecific differences in seed dispersal alter th...

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Bibliographic Details
Published in:Theoretical ecology 2020-12, Vol.13 (4), p.551-581
Main Authors: Stump, Simon Maccracken, Comita, Liza S.
Format: Article
Language:English
Subjects:
Animal behavior
Biomedical and Life Sciences
Coexistence
Conspecifics
Dispersion
Interspecific
Life Sciences
Natural enemies
Niches
Original Paper
Plant Sciences
Plant species
Seed dispersal
Seedlings
Species
Theoretical Ecology/Statistics
Tradeoffs
Zoology
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Summary:Seed dispersal is a critical mechanism for escaping specialist natural enemies. Despite this, mean dispersal distances can vary by an order of magnitude among plant species in the same community. Here, we develop a theoretical model to explore how interspecific differences in seed dispersal alter the impact of specialist natural enemies, both on their own and though a trade-off between seed dispersal and enemy susceptibility. Our model suggests that species are more able to recover from rarity if they have high dispersal because (1) seedlings are more likely to escape their parent’s natural enemies, (2) adults are more spread out, reducing the chance that a seed will disperse near conspecifics, and (3) seedlings compete less with kin for open gaps. Differences in dispersal do not produce stabilizing mechanisms—species with low dispersal are purely at a disadvantage and do not gain a novel niche opportunity. However, dispersal-susceptibility trade-offs will be equalizing, as species disadvantaged by low dispersal will benefit from being less susceptible to specialist natural enemies. This mechanism, unlike most mechanisms of dispersal-mediated coexistence, does not require that there is an abundance of empty space: high-dispersers gain an advantage by escaping from their enemies, not by colonizing empty habitat. Our study therefore suggests that differences in dispersal are unlikely to promote diversity on their own, but may strengthen other coexistence mechanisms.
ISSN:1874-1738
1874-1746
DOI:10.1007/s12080-020-00468-5