Title

Multiple source pools and dispersal barriers for Galapagos plant species distribution

Authors

Authors

J. A. Yeakley;J. F. Weishampel

Abbreviated Journal Title

Ecology

Keywords

connectivity and species number; dispersal barriers, plant; elevation; barriers to dispersal; extinction; Galapagos Archipelago; habitat; diversity; immigration; island biogeography; oceanic pathways of plant; dispersal; plant species richness; source pools and plant species; richness; species dispersal in archipelagos; ISLAND BIOGEOGRAPHY; NUMBER; IMMIGRATION; ARCHIPELAGO; EXTINCTION; AREA; Ecology

Abstract

We reexamined geographic factors explaining the number of plant species on islands in the Galapagos Archipelago. We hypothesized that plant species richness (S) was related to the number of source pools and that plant species dispersal preferentially followed direct, oceanic pathways. To test different dispersal pathways from multiple source pools, the total number of islands within a given dispersal radius (i) was posed as the sum of the number of line-of-sight islands (C-i) and of the number of islands without line-of-sight connection (B-i). In partial regression analyses, controlling for nearest island area (A(2)) and for recipient island elevation (E) and area (InA), C-i and C-i x E were found to be positively correlated with S in the Galapagos for nearly all dispersal ranges from 10 km to 419 km (maximum inter-island separation). In contrast, B-i x E was negatively correlated with S at the longest dispersal ranges. The connectivity index, C-i, multiplied by elevation, E, explained more variation in S in the Galapagos than prior regression models using additive forms of E, InA, A(2), and isolation from the central island. Using the variables C-i x E and InA, multiple-regression models explained >90% of the variance in both endemic and total plant species richness in the Galapagos Archipelago.

Journal Title

Ecology

Volume

81

Issue/Number

4

Publication Date

1-1-2000

Document Type

Article

Language

English

First Page

893

Last Page

898

WOS Identifier

WOS:000086351500002

ISSN

0012-9658

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