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A Minimal Model for the Latitudinal Diversity Gradient Suggests a Dominant Role for Ecological Limits.
Am Nat. 2019 11; 194(5):E122-E133.AN

Abstract

The latitudinal diversity gradient (LDG) is one of Earth's most iconic biodiversity patterns and still one of the most debated. Explanations for the LDG are often categorized into three broad pathways in which the diversity gradient is created by (1) differential diversification rates, (2) differential carrying capacities (ecological limits), or (3) differential time to accumulate species across latitude. Support for these pathways has, however, been mostly verbally expressed. Here, we present a minimal model to clarify the essential assumptions of the three pathways and explore the sensitivity of diversity dynamics to these pathways. We find that an LDG arises most easily from a gradient in ecological limits compared with a gradient in the time for species accumulation or diversification rate in most modeled scenarios. Differential diversification rates create a stronger LDG than ecological limits only when speciation and dispersal rates are low, but then the predicted LDG seems weaker than the observed LDG. Moreover, range dynamics may reduce an LDG created by a gradient in diversification rates or time for species accumulation, but they cannot reduce an LDG induced by differential ecological limits. We conclude that our simple model provides a null prediction for the effectiveness of the three LDG pathways and can thus aid discussions about the causal mechanisms underlying the LDG or motivate more complex models to confirm or falsify our findings.

Authors

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Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

31613672

Citation

Etienne, Rampal S., et al. "A Minimal Model for the Latitudinal Diversity Gradient Suggests a Dominant Role for Ecological Limits." The American Naturalist, vol. 194, no. 5, 2019, pp. E122-E133.
Etienne RS, Cabral JS, Hagen O, et al. A Minimal Model for the Latitudinal Diversity Gradient Suggests a Dominant Role for Ecological Limits. Am Nat. 2019;194(5):E122-E133.
Etienne, R. S., Cabral, J. S., Hagen, O., Hartig, F., Hurlbert, A. H., Pellissier, L., Pontarp, M., & Storch, D. (2019). A Minimal Model for the Latitudinal Diversity Gradient Suggests a Dominant Role for Ecological Limits. The American Naturalist, 194(5), E122-E133. https://doi.org/10.1086/705243
Etienne RS, et al. A Minimal Model for the Latitudinal Diversity Gradient Suggests a Dominant Role for Ecological Limits. Am Nat. 2019;194(5):E122-E133. PubMed PMID: 31613672.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A Minimal Model for the Latitudinal Diversity Gradient Suggests a Dominant Role for Ecological Limits. AU - Etienne,Rampal S, AU - Cabral,Juliano Sarmento, AU - Hagen,Oskar, AU - Hartig,Florian, AU - Hurlbert,Allen H, AU - Pellissier,Loïc, AU - Pontarp,Mikael, AU - Storch,David, Y1 - 2019/08/23/ PY - 2019/10/16/entrez PY - 2019/10/16/pubmed PY - 2020/5/20/medline KW - dispersal KW - diversification KW - ecological limits KW - extinction KW - latitudinal diversity gradient KW - speciation SP - E122 EP - E133 JF - The American naturalist JO - Am Nat VL - 194 IS - 5 N2 - The latitudinal diversity gradient (LDG) is one of Earth's most iconic biodiversity patterns and still one of the most debated. Explanations for the LDG are often categorized into three broad pathways in which the diversity gradient is created by (1) differential diversification rates, (2) differential carrying capacities (ecological limits), or (3) differential time to accumulate species across latitude. Support for these pathways has, however, been mostly verbally expressed. Here, we present a minimal model to clarify the essential assumptions of the three pathways and explore the sensitivity of diversity dynamics to these pathways. We find that an LDG arises most easily from a gradient in ecological limits compared with a gradient in the time for species accumulation or diversification rate in most modeled scenarios. Differential diversification rates create a stronger LDG than ecological limits only when speciation and dispersal rates are low, but then the predicted LDG seems weaker than the observed LDG. Moreover, range dynamics may reduce an LDG created by a gradient in diversification rates or time for species accumulation, but they cannot reduce an LDG induced by differential ecological limits. We conclude that our simple model provides a null prediction for the effectiveness of the three LDG pathways and can thus aid discussions about the causal mechanisms underlying the LDG or motivate more complex models to confirm or falsify our findings. SN - 1537-5323 UR - https://www.unboundmedicine.com/medline/citation/31613672/A_Minimal_Model_for_the_Latitudinal_Diversity_Gradient_Suggests_a_Dominant_Role_for_Ecological_Limits_ L2 - https://doi.org/10.1086/705243 DB - PRIME DP - Unbound Medicine ER -