Date of Award

Summer 8-1-2007

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Biology

First Advisor

John O. Whitaker

Second Advisor

Thomas P. Simon

Third Advisor

Peter E. Scott

Abstract

I investigated the distribution, zoogeography, and habitat associations of crayfish (Decapoda: Cambaridae) in an area of west central Indiana containing glaciated and unglaciated regions. I first sampled 180 streams within Vigo, Clay, Owen, Sullivan, Greene, and Knox counties to establish spatial distributions of crayfish species and gather information on natural history and site specific habitat conditions. Ten species were found; Cambarus (Tubericambarus) polychromatus, Cambarus (Lacunicambarus) sp.A, Cambarus (Erebicambarus) laevis, Fallicambarus (Creaserinus)fodiens, Procambarus (Girardiella) gracilis, Procambarus (Ortmannicus) acutus, Orconectes (Triscellescens) immunis, Orconectes ( Gremicambarus) virilis, Orconectes ( Crockerinus) propinquus, - Orconectes (Faxinous) indianensis. The two rarest species were 0. indianensis (collected at four sites) and P. gracilis (collected at one site. Morphometric data for 23 ovigerous females of four species was recorded. Second, I investigated the spatial distribution of each species in relation to dispersal from glacial refugia following Pleistocene ice advance. Of the nine species occurring in glaciated habitat only 0. propinquus possibly dispersed from a northern refuge. The extensive ice-free area within the Missouri River along with areas south of the glacial terminus were important glacial refugia for the crayfish of western Indiana and eastern Illinois. Third, I investigated associations of crayfish with reach and watershed scale habitat, land use, and water quality. Reach models predicted assemblage structure variables better than watershed models. Watershed models were stronger predictors of crayfish structure within the unglaciated region. Both reach and watershed models developed for individual species were successful in predicting species abundance. Stronger models were developed for aquatic species than for terrestrial species. A variety of habitat and water quality characteristics at the reach scale, most notably instream cover amount and complexity, appeared as important predictors. Forested riparian and watershed land use were important watershed scale predictors.

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