Identifier

etd-0419102-000538

Degree

Doctor of Philosophy (PhD)

Department

Biological Sciences

Document Type

Dissertation

Abstract

A series of spatially based models of Hawaiian streams and stream fish habitats were developed to aid in the conservation of native fishes. The spatial models focused on the quantification of habitat for native fishes at three levels within a spatial hierarchy. First, at the reach level, the models classified the major geomorphological features of a stream and its watershed to determine the distribution of fish habitat within the different sections of the stream. The distribution of habitat was combined with habitat suitability criteria and the migratory abilities of the native fishes to quantify available habitat and predict expected community membership within a reach. The reach model correctly predicted 87 of 98 possible species presence or absence combinations, and only once predicted a species would not occur in a reach where field surveys verified its existence. At the stream level, a new classification system for Hawaiian streams based on the streams’ major morphological characteristics was developed. Cluster analysis of 150 perennial streams resulted in eight stream types differentiated by their size, shape, position of the steepest slope, and extent of bay development. Within each stream type, the amount of habitat available for the native fishes was quantified. The amount of native fish habitat was non-randomly distributed among stream types. At the island level, the distribution of stream types and amount of habitat were determined for each island. The distribution of stream types changed consistently along with the age of the islands. The distribution of fish habitat also changed with island age, and habitats for some species were associated with the younger islands while other habitats were associated with older islands. The spatial models support the role of available habitat in the structuring of native fish populations yet allow for future models concerning the large-scale recruitment processes to be integrated with these habitat models. The spatial habitat models derive an expected natural distribution of stream fishes and stream fish habitats. These expected distributions can be used to restrict comparisons to similar habitats. These spatial models also will provide a naturally expected goal for stream restoration projects in highly altered stream conditions.

Date

2002

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

J. Michael Fitzsimons

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