Towards a glacial‐sensitive model of island biogeography

Abstract

Although the role that Pleistocene glacial cycles have played in shaping the present biota of oceanic islands world‐wide has long been recognized, their geographical, biogeographical and ecological implications have not yet been fully incorporated within existing biogeographical models. Here we summarize the different types of impacts that glacial cycles may have had on oceanic islands, including cyclic changes in climate, shifts in marine currents and wind regimes and, especially, cycles of sea level change. The latter have affected geographical parameters such as island area, isolation and elevation. They have also influenced the configurations of archipelagos via island fusion and fission, and cycles of seamount emergence and submergence. We hypothesize that these sea level cycles have had significant impacts on the biogeographical processes shaping oceanic island biotas, influencing the rates and patterns of immigration and extinction and hence species richness. Here we provide a first step toward the development of a glacial‐sensitive model of island biogeography, representing the tentative temporal evolution of those biogeographical parameters during the last glacial cycle. From this reasoning we attempt to derive predictions regarding the imprint of sea level cycles on genetic, demographic or biogeographical patterns within remote island biotas.

Assessing predicted isolation effects from the general dynamic model of island biogeography with an eco‐evolutionary model for plants

“…However, isolation changes at various time‐scales, from recently increased source pools via human‐induced activities and dispersal (i.e. alien species; Kueffer et al, ), over climate‐mediated changes in sea levels (Fernández‐Palacios et al, ; Weigelt et al, ), to deep time‐scales of plate tectonics, archipelagic dynamics and eco‐evolutionary changes in the source pool. Moreover, intra‐archipelagic isolation may play an important role for trends of single‐island endemics (Borregaard et al, ; Cabral et al, ), and thus, further insights might be gained by disentangling isolation in relation to intra‐archipelagic versus mainland source pools.…”

Pleistocene extinctions as drivers of biogeographical patterns on the easternmost Canary Islands

“…The ECI also have a particular ontogeny. Following Pleistocene oscillations, the fusion of these two islands and nearby islets throughout recurrent stadial periods resulted in an emerged surface area, known as Mahan, that was up to two times larger than at present (Figure a; see also Fernández‐Palacios et al., ). The relatively low topological complexity of Mahan probably allowed plant and animal dispersal, providing genetic homogeneity across the extension of the currently separated islands (Caujapé‐Castells et al., ).…”

“…large emerged area and closeness to other sources of potential colonizers) could have offered high opportunities for island colonization (e.g. Fernández‐Palacios et al., ).…”

Biodiversity Dynamics on Islands: Explicitly Accounting for Causality in Mechanistic Models

“…Other processes known to have major impacts on biodiversity, but hitherto absent explicitly in models, include glaciation-induced sea level oscillations [71,72] or anthropogenic influences [73]. However, one initialization scenario of Rosindell and Harmon [28] reflects a sea level change that separates a landmass from the mainland, which thus harbors a subset of the mainland species pool.…”