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Topography‐driven isolation, speciation and a global increase of endemism with elevation
Author(s) -
Steinbauer Manuel J.,
Field Richard,
Grytnes JohnArvid,
Trigas Panayiotis,
AhPeng Claudine,
Attorre Fabio,
Birks H. John B.,
Borges Paulo A. V.,
Cardoso Pedro,
Chou ChangHung,
De Sanctis Michele,
de Sequeira Miguel M.,
Duarte Maria C.,
Elias Rui B.,
FernándezPalacios José María,
Gabriel Rosalina,
Gereau Roy E.,
Gillespie Rosemary G.,
Greimler Josef,
Harter David E. V.,
Huang TsurngJuhn,
Irl Severin D. H.,
Jeanmonod Daniel,
Jentsch Anke,
Jump Alistair S.,
Kueffer Christoph,
Nogué Sandra,
Otto Rüdiger,
Price Jonathan,
Romeiras Maria M.,
Strasberg Dominique,
Stuessy Tod,
Svenning JensChristian,
Vetaas Ole R.,
Beierkuhnlein Carl
Publication year - 2016
Publication title -
global ecology and biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.164
H-Index - 152
eISSN - 1466-8238
pISSN - 1466-822X
DOI - 10.1111/geb.12469
Subject(s) - endemism , species richness , elevation (ballistics) , ecology , biogeography , biology , genetic algorithm , geography , physics , astronomy
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.