FRESHWATER CRAYFISH | 2011| vol. 18| issue 1 | Research Article
 
doi: 10.5869/fc.2011.v18.37 |  View Table of Contents

Full Citation: Distefano RJ and Westhoff JT (2011). Range expansion by an invasive crayfish and subsequent range contraction of imperiled endemic crayfish in Missouri (USA) Ozark streams. Freshwater Crayfish 18(1): 37-44.



Range expansion by an invasive crayfish and subsequent range contraction of imperiled endemic crayfish in Missouri (USA) Ozark streams

Distefano RJ and Westhoff JT

Abstract:
Orconectes hylas is endemic to three Missouri (USA) drainages but invaded the St. Francis River drainage (SFRD), in the late 20th century. Data from 1984 suggest O. hylas occurred in only one SFRD stream reach, but data from the 1990s suggest the invader expanded its range to reaches of three streams. Simultaneously, two endemic imperiled species, Orconectes peruncus and Orconectes quadruncus, declined in those streams, eliciting concern about extirpations. Confirmation of presumed O. hylas SFRD range expansion and information on expansion rates would benefit conservation planning for the imperiled species. Objectives were to 1) confirm/refute O. hylas range expansion in two SFRD streams over several consecutive years, 2) estimate rates of confirmed range expansion, 3) document possible range contractions of imperiled crayfish. We sampled crayfish to determine the invasion’s “leading edge” using baited traps and seines in Carver and Orr Hollow creeks during five and eight nearly consecutive summers, respectively. Orconectes hylas expanded its range in both streams; O. peruncus’ range contracted in invaded reaches of Carver Creek. Despite O. hylas expansion, O. quadruncus persisted in Orr Hollow Creek, apparently at lower abundances. Invasion rates varied greatly between streams and among years, creating uncertainty in predicting future range expansions.

Keywords: imperiled crayfish; invasive crayfish; Orconectes conservation

Article Language: English

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