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Abstract Understanding mechanisms of coexistence is a central topic in ecology. Mathematical analysis of models of competition between two identical species moving at different rates of symmetric diffusion in heterogeneous environments show that the slower mover excludes the faster one. The models have not been tested empirically and lack inclusions of a component of directed movement toward favourable areas. To address these gaps, we extended previous theory by explicitly including exploitable resource dynamics and directed movement. We tested the mathematical results experimentally using laboratory populations of the nematode worm,Caenorhabditis elegans. Our results not only support the previous theory that the species diffusing at a slower rate prevails in heterogeneous environments but also reveal that moderate levels of a directed movement component on top of the diffusive movement allow species to coexist. Our results broaden the theory of species coexistence in heterogeneous space and provide empirical confirmation of the mathematical predictions.
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Dormancy promotes coexistence in fluctuating environments
Dormancy allows organisms to survive hostile conditions and is hypothesized to enable species to coexist in fluctuating environments. Although determining how species avoid extinction is critical to understanding the dynamics of natural populations, experimental work exploringifandwhendormancy rescues populations from extinction remains rare. We conducted an experiment, where we grew two species of nematode at three temperatures. Strains ofCaenorhabditiseleganshad mutations altering their propensity to enter a dormant stage andCaenorhabditis briggsaewas a single strain with a wildtype background. We used those empirical results to parameterize a model and simulate competitive outcomes in fluctuating environments between the two species. We show that upregulating the dormancy pathway rescues populations that would otherwise go extinct, thereby increasing coexistence between competing species. By leveraging the genetic tools available from a model system, this study provides experimental confirmation that dormancy specifically facilitates species coexistence and thereby promotes diversity. This study system could be used more expansively to explore the role of dormancy in species interactions.
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- Award ID(s):
- 1936674
- PAR ID:
- 10552289
- Publisher / Repository:
- Nordic Society Oikos
- Date Published:
- Journal Name:
- Oikos
- ISSN:
- 0030-1299
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1111/oik.10503
