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Extreme and short-lasting sea-level stands structure insular species diversity of a continental-shelf archipelago (Aegean Sea, Greece)
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  • Cyril Hammoud,
  • Konstantinos Kougioumoutzis,
  • Kenneth F. Rijsdijk,
  • Stylianos Simaiakis,
  • Sietze Norder,
  • E. Emiel Van Loon
Cyril Hammoud
Ghent University
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Konstantinos Kougioumoutzis
University of Athens
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Kenneth F. Rijsdijk
Universiteit van Amsterdam
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Stylianos Simaiakis
Natural History Museum - Crete
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Sietze Norder
Universidade de Lisboa
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E. Emiel Van Loon
Universiteit van Amsterdam
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Abstract

Recent research in island biogeography has highlighted the important role of late Quaternary sea-level fluctuations in shaping biogeographical patterns in insular systems, but largely focused on volcanic oceanic systems. Through this study we aim to extend this work by investigating the role of late Quaternary sea-level fluctuations in shaping species richness patterns in continental shelf island systems. Focusing on the Aegean archipelago, we first reconstructed the area’s geography using published data, under three sea-level stands: 1) current; 2) median over the last nine Glacial-Interglacial cycles; 3) Late Glacial Maximum (LGM). We compiled taxon-island occupancy for angiosperms (70 islands) and centipedes (56 islands). We investigated the impact of present-day and past geographical settings on chorological groups by analysing Island Species-Area Relationships (ISARs) and using Generalized Linear Mixed Models selection based on multiple metrics of goodness-of-fit. Our results confirm that the Aegean’s geography has changed dramatically since the LGM, while the median sea-level scenario only modestly differs from the present configuration. Paleogeographical changes largely shaped Aegean plant diversity patterns, and to a lesser degree centipede species richness patterns. The LGM geographic configuration affected both native and endemic species diversity through establishing connections between land-bridge islands and the mainland. Particularly on land-bridge islands we detected supersaturation of native species and stronger underrepresentation of endemics on those same islands. Unlike oceanic islands, where the longer lasting median configuration has ample effect on the current species diversity, the shorter lasting LGM configurations promoted increased connectivity with the mainland counteracting processes promoting endemism. Our study shows that in terms of processes affecting species richness patterns, continental archipelagos differ fundamentally from oceanic systems, highlighting the importance of distinguishing between them while studying biota from the perspective of historical biogeography.

Peer review status:IN REVISION

21 Apr 2020Submitted to Ecology and Evolution
23 Apr 2020Assigned to Editor
23 Apr 2020Submission Checks Completed
24 Apr 2020Reviewer(s) Assigned
03 May 2020Review(s) Completed, Editorial Evaluation Pending
07 May 2020Editorial Decision: Revise Minor