Bird Conservation International

Research Articles

Galápagos Rail Laterallus spilonotus population change associated with habitat invasion by the Red-barked Quinine Tree Cinchona pubescens

W. GREGORY SHRIVERa1 c1, JAMES P. GIBBSa2, HARA W. WOLTZa3, NICOLE P. SCHWARZa4 and MARGARET A. PEPPERa5

a1 Department of Entomology and Wildlife Ecology, University of Delaware, Newark, DE 19717, USA.

a2 State University of New York, College of Environmental Science and Forestry, 1 Forestry Drive, Syracuse, New York 13210, USA.

a3 Columbia University Department of Ecology, Evolution, and Environmental Biology 10th Floor Schermerhorn Ext. 1200 Amsterdam Avenue New York, New York 10027, USA.

a4 Charles Darwin Research Station, Puerto Ayora, Santa Cruz Island Galápagos, Ecuador.

a5 Department of Entomology and Wildlife Ecology, University of Delaware, Newark, DE 19717, USA.

Summary

Species on oceanic islands are more likely to be endemic as well as more extinction-prone than those on continents. The Galápagos Rail Laterallus spilonotus, endemic to the Galápagos Archipelago, is presently known to occur on just four of its seven previously occupied islands and is facing multiple threats to its persistence. In this study, we compared the rail’s occurrence and abundance at 193 survey points between 2000 and 2007 on Santa Cruz Island and examined the influence of an invasion of the habitat of the species by the exotic Red-barked Quinine Tree Cinchona pubescens. We detected a 13% reduction in rail occurrence and a 31% reduction in abundance between 2000 and 2007. Rail abundance declined more in low elevation areas (< 719 m) and outside of Cinchona pubescens removal areas but not in areas where Cinchona pubescens was removed. Insofar as Galápagos Rails responded positively to management actions that promote and maintain native vegetation, we conclude that restoration projects that restore native vegetation communities benefit this apparently declining endemic bird for which more focused conservation attention is warranted.

(Received April 08 2010)

(Accepted July 07 2010)

(Online publication November 03 2010)

Correspondence:

c1 Author for correspondence; e-mail gshriver@udel.edu