Topography-driven isolation, speciation and a global increase of endemism with elevation

Steinbauer, Manuel J. and Field, Richard and Grytnes, John Arvid and Trigas, Panayiotis and Ah-Peng, Claudine and Attore, Fabio and Birks, H. John B. and Borges, Paulo A.V. and Cardoso, Pedro and Chou, Chang-Hung and De Sanctis, Michele (2016) Topography-driven isolation, speciation and a global increase of endemism with elevation. Global Ecology and Biogeography . ISSN 1466-8238

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Abstract

Aim: Higher-elevation areas on islands and continental mountains tend to be separated by longer distances, predicting higher endemism at higher elevations; our study is the first to test the generality of the predicted pattern. We also compare it empirically with contrasting expectations from hypotheses invoking higher speciation with area, temperature and species richness.

Location: Thirty-two insular and 18 continental elevational gradients from around the world.

Methods: We compiled entire floras with elevation-specific occurrence information, and calculated the proportion of native species that are endemic (‘percent endemism’) in 100-m bands, for each of the 50 elevational gradients. Using generalized linear models, we tested the relationships between percent endemism and elevation, isolation, temperature, area and species richness.

Results: Percent endemism consistently increased monotonically with elevation, globally. This was independent of richness–elevation relationships, which had varying shapes but decreased with elevation at high elevations. The endemism–elevation relationships were consistent with isolation-related predictions, but inconsistent with hypotheses related to area, richness and temperature.

Main conclusions: Higher per-species speciation rates caused by increasing isolation with elevation are the most plausible and parsimonious explanation for the globally consistent pattern of higher endemism at higher elevations that we identify. We suggest that topography-driven isolation increases speciation rates in mountainous areas, across all elevations and increasingly towards the equator. If so, it represents a mechanism that may contribute to generating latitudinal diversity gradients in a way that is consistent with both present-day and palaeontological evidence.

Item Type: Article
Additional Information: This is the peer reviewed version of the following article: teinbauer, M. J., Field, R., Grytnes, J.-A., Trigas, P., Ah-Peng, C., Attorre, F., Birks, H. J. B., Borges, P. A. V., Cardoso, P., Chou, C.-H., De Sanctis, M., de Sequeira, M. M., Duarte, M. C., Elias, R. B., Fernández-Palacios, J. M., Gabriel, R., Gereau, R. E., Gillespie, R. G., Greimler, J., Harter, D. E. V., Huang, T.-J., Irl, S. D. H., Jeanmonod, D., Jentsch, A., Jump, A. S., Kueffer, C., Nogué, S., Otto, R., Price, J., Romeiras, M. M., Strasberg, D., Stuessy, T., Svenning, J.-C., Vetaas, O. R., Beierkuhnlein, C. (2016), Topography-driven isolation, speciation and a global increase of endemism with elevation. Global Ecology and Biogeography, which has been published in final form at http://dx.doi.org/10.1111/geb.12469. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
Keywords: Altitude; biogeographical processes; diversity; ecological mechanisms; endemism; global relationship; isolation; latitudinal gradient; mixed-effects models; sky islands
Schools/Departments: University of Nottingham UK Campus > Faculty of Social Sciences > School of Geography
Identification Number: https://doi.org/10.1111/geb.12469
Depositing User: Eprints, Support
Date Deposited: 22 Jun 2016 13:00
Last Modified: 14 Sep 2016 01:22
URI: http://eprints.nottingham.ac.uk/id/eprint/34319

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