Evaluating the Relationship Between Habitat Interspersion and Abundance of the Hawaiian Gallinule.
Munoz, M. Alejandra.
- Habitat selection is a crucial behavioral process that affects fitness and reproductive success in animal species. Understanding habitat selection also has strong implications for the success of habitat management plans and the conservation of endangered species. The endangered Hawaiian Gallinule (Gallinula galeata sandvicensis) is a wetland specialist endemic to two islands in Hawaii. It has ... read moresuffered extensive habitat loss, particularly through conversion for agriculture and by extensive urbanization; the remaining habitat has a fragmented distribution. This loss is severe on the island of Oahu, where 75% of its wetlands have been lost since human arrival to the island. Despite its importance, little research has been published for this species and little is known about the details of Hawaiian gallinule habitat requirements beyond basic associations, mostly garnered from studies of other subspecies. My research focuses on understanding the effect of interspersion, defined as the intermixing of water, emergent vegetation, floating vegetation, and bare ground, on the abundance of the Hawaiian gallinule. We gathered abundance and interspersion data at freshwater coastal wetlands along the coast of the island of Oahu between the months of May and August 2015-2017.We determined the relationship between five interspersion metrics (Contagion, Edge Density, Edge Length, Edge Index, and Simpson’s Diversity Index) and gallinule abundance using general linear models. Our analyses revealed that, among the interspersion metrics we evaluated, edge length is the best predictor of gallinule abundance in ponds on the island of Oahu. We therefore believe that the direct creation of interspersion with an emphasis on maximizing emergent/water edges could be an indispensable management tactic at increasing gallinule numbers.read less