Distribution of threatened crayfishes and spread of an invasive crayfish in the upper Saint Francis River drainage, Missouri
No Thumbnail Available
Authors
Meeting name
Sponsors
Date
Journal Title
Format
Thesis
Subject
Abstract
Crayfish invasions are among the top global threats to native crayfish populations. The Saint Francis River Crayfish Faxonius quadruncus and Big Creek Crayfish Faxonius peruncus, endemic to the upper Saint Francis River (USFR) drainage in Missouri, are under threat of extinction due to invasion of the Woodland Crayfish Faxonius hylas from nearby drainages. Previous research documented reduced abundances and range reductions for both native species in reaches invaded by F. hylas, but recent and comprehensive distribution data for these species are lacking. In 2022-23, I conducted the first systematic, basin-wide distribution survey of crayfish in the USFR drainage and located leading edges (i.e., estimated upstream or downstream range extent) of F. hylas invasion in six streams. The distribution survey provided updated locality data for both endemic crayfishes and for invasive F. hylas in 96 sites, and it supplied training data for species distribution models. Random forest and boosted regression models trained with coarse-scale environmental predictors, spatial stream network models, and ensemble models predicted species presence in stream segments across the drainage. Cross-validated prediction error rates for the best performing models were less than 10 percent. Distribution and leading-edge surveys documented newly discovered invasions of F. hylas in two tributaries to the USFR drainage and a range expansion of F. hylas 1.4 km upstream from the 2009 leading edge in Orr Hollow Creek. The results of this study provide pertinent information for the recovery planning of threatened F. quadruncus and F. peruncus and can be used to identify potential refugia for native species, prioritize locations for long-term monitoring, and inform United States Endangered Species Act consultations and reviews.
Table of Contents
DOI
PubMed ID
Degree
M.S.