Effects of Intrinsic and Extrinsic Factors on Population Fragmentation in Three Species of North American Minnows (Teleostei: Cyprinidae)

Abstract

Abstract.-Geographic patterns of genetic variation (mitochondrial DNA [mtDNA] and allozymes) were used to examine effects of intrinsic characteristics (e.g., vagility, habitat specificity, and reproductive behaviors) and extrinsic factors (e.g., climatic and geological history) on population fragmentation.The three species of cyprinid fishesexamined (Tiaroga cobitis, Meda fulgida, and Agosia chrysogaster) occupied similar historical ranges within the lower Colorado River drainage, but differ in intrinsic characteristics conducive to population fragmentation. Relationships among populations were similar across species, reflecting common historical influences, but results indicate the distribution of variation among species is strongly affected by intrinsic characteristics. Variation within two species (T. cobitis and M. fulgida) is subdivided among populations, suggesting little gene flow among rivers. In contrast, similarity of A. chrysogaster populations throughout the Gila River drainage supports the hypothesis that levels of gene flow are high for this species. Levels of mtDNA divergence were much higher than expected for both T. cobitis and A. chrysogaster suggesting long-term isolation of geographic regions. These results indicate that both long-term and short-term extrinsic factors have shaped basic patterns of variation within these fishes; however, the intrinsic characteristics of each species have strongly affected the population genetic structure of these fishes.

Influence of Introgression and Geological Processes on Phylogenetic Relationships of Western North American Mountain Suckers (Pantosteus, Catostomidae)

“…Genomic DNA was extracted from muscle tissue using the DNeasy Tissue Kit (QIAGEN Inc., Chatsworth CA) or by phenol-chloroform extraction as described in [46]. Nine of the 13 mtDNA protein coding genes (ND1, ND2, ND4L, ND4, ND5, ND6, ATPase6/8, cyt b and partial sequence from COIII) were amplified, representing approximately half of the mitochondrial genome (8055 bp).…”

Multi‐scale effects of impoundments on genetic structure of creek chub (Semotilus atromaculatus) in the Kansas River basin

“…Although dams, irrigation diversions and other waterway alterations are common features in contemporary aquatic systems (Benke, 1990), the genetic effects of fragmentation in running water habitats has been restricted to a limited number of taxa, many of which occur in mainstem habitats (e.g. Hence, there is an urgent need to understand the genetic consequences and potentially infer the demographic consequences of fragmentation in different lotic habitats because a clear understanding of patterns of genetic diversity is of central importance to developing conservation strategies that encourage the persistence of aquatic organisms in changing landscapes (Ryman, Utter & Laikre, 1995;Tibbets & Dowling, 1996;Aló & Turner, 2005). Nevertheless, recent evidence suggests that impacts of habitat fragmentation on genetic structure of stream fishes are likely to depend on ecological traits of those species.…”

Synthesis of Upper Verde River research and monitoring 1993-2008

“…Isolation of the spikedace in the UVR from spikedace of the Gila River and Aravaipa Creek dates at least to completion of the Horseshoe and Bartlett dams on the Verde in the 1930s. Analyses of spikedace populations in the Gila River system (Tibbets and Dowling 1996) suggest that the population of spikedace in the UVR is genetically distinct. Accordingly, no translocation of spikedace should occur unless there is unequivocal evidence that the spikedace has been extirpated from the UVR drainage.…”