Search

Assessing genetic variation in species of conservation concern is critical for developing sound recovery strategies. In this study, we compared sympatric populations of two related species, the endangered Quadrula fragosa (Conrad, 1836) and its common relative Amphinaias pustulosa (Lea, 1831), using standard genetic parameters such as allelic richness, heterozygosity, and effective population size. Our primary aim was to determine if a small population size and isolation from conspecifics had negatively affected the genetic diversity of this population of Q. fragosa. By comparing the endangered species to a related and sympatric, common species we can assess the rare species for genetic effects associated with reduced population size, and in addition, develop management targets for what a recovered Q. fragosa population looks like genetically. Examination of eight microsatellite loci indicated that Quadrula fragosa exhibited reduced genetic variation when compared to A. pustulosa at all measures,...

Early life history information on the federally endangered winged mapleleaf (Quadrula fragosa (Conrad, 1835)) mussel is needed by natural resource managers to improve conservation and propagation programs. We conducted four studies to obtain some of this information. First, we observed Q. fragosa in the St. Croix River, Wisconsin between 1997–2010 and found females brood larvae (glochidia) for a unique period, between 8 September to 8 October at water temperatures ranging between 15–21 °C Second, we tested 67 fish species and Necturus maculosus for their ability to transform glochidia into juveniles. Nearly 30,000 juvenile Q. fragosa were produced, but only on Ictalurus furcatus and I. punctatus. Unlike most mussel species, Q. fragosa glochidia grew 3 to 4-fold while attached. Third, using scanning electron microscopy we were able to distinguish Q. fragosa glochidia height and length from six other mussel species that also produce small glochidia (

1. North America is a globally important centre of freshwater mussel biodiversity. Accurate population estimates and descriptions of critical habitat for endangered species of mussels are needed but are hindered by their patchy distribution and the dynamic nature of their habitat. Adaptive cluster sampling (ACS) was used to estimate population size and habitat associations of two federally endangered species, Higgins eye (Lampsilis higginsii) and winged mapleleaf (Quadrula fragosa), in the St. Croix River. 2. This river holds the largest known winged mapleleaf population in the upper Mississippi River and contains Essential Habitat Areas for Higgins eye. Winged mapleleaf density ranged from 0.008–0.020 individuals m−2 (coefficient of variation=50–66%), yielding an estimate of 13 000 winged mapleleaf in this reach of the river. Higgins eye density varied from 0.008–0.015 individuals m−2 (coefficient of variation=66–167%) giving an estimate of 14 400 individuals in this area. 3. Higgins eye and winged mapleleaf were associated with areas of the overall highest mussel density and species richness, suggesting these endangered species occur in ‘premier’ mussel habitat. There were no differences in many microhabitat factors for sites with and without either endangered species. Select hydraulic measures (such as shear velocity and shear stress) showed significant differences in areas with and without the winged mapleleaf but not for Higgins eye. Areas that are less depositional support dense and diverse mussel assemblages that include both endangered species, with winged mapleleaf having a narrower habitat range than Higgins eye. 4. This study suggests that ACS can provide statistically robust estimates of density with 2–3 times more efficiency than simple random sampling. ACS, however, was quite time consuming. This work confirmed that of others demonstrating that larger-scale hydraulic parameters might be better predictors of prime mussel habitat than fine-scaled microhabitat factors. Using hydraulic measures may allow improved identification of potentially critical mussel habitat. Copyright © 2009 John Wiley & Sons, Ltd.

We reviewed the conservation status of rare and endangered species of mussels in southeastern Oklahoma by completing surveys of 10 long-term monitoring sites on the Kiamichi River and five sites in the Little River. We found extant populations of the Ouachita rock pocketbook, Arkansia wheeleri, scaleshell, Leptodea leptodon, winged mapleleaf, Quadrula fragosa, and rabbitsfoot, Quadrula cylindrica cylindrica. This is the first reported documentation of Q. fragosa in the Little River. When our data are compared to historic records, populations, particularl yo fA. wheeleri and Q. cylindrica, appear to be declining. RESUMEN—Revisamos el estado de conservacion de las especies raras de mejillones y en peligro de extincion en 10 sitios de muestreo a largo plazo en el ro ´o Kiamichi y 5 sitios en el ro ´o Little en el sureste de Oklahoma. Encontramos poblaciones existentes de Arkansia wheeleri, Leptodea leptodon, Quadrula fragosa y Quadrula cylindrica cylindrica. Reportamos por primera vez a Q. fragosa en el ro ´o Little. Cuando los resultados son comparados con registros historicos, las poblaciones, particularmente de A. wheeleri y Q. cylindrica, parecen estar disminuyendo.

The winged mapleleaf mussel [Quadrula fragosa (Conrad)] is a Federal endangered species. Controlled propagation to aid in recovering this species has been delayed because host fishes for its parasitic glochidia (larvae) are unknown. This study identified blue catfish [Ictaluris furcatus (Lesueur)] and confirmed channel catfish [Ictaluris punctatus (Rafinesque)] as suitable hosts. The time required for glochidia to metamorphose and for peak juvenile excystment to begin was water temperature dependent and ranged from 28 to 37 d in a constant thermal regime (19 C); totaled 70 d in a varied thermal regime (12–19 C); and ranged 260 to 262 d in simulated natural thermal regimes (0–21 C). We developed a quantitative model that describes the thermal-temporal relation and used it to empirically estimate the species-specific low-temperature threshold for development of glochidia into juveniles on channel catfish (9.26 C) and the cumulative temperature units of development required to achieve peak excystmen...

We examined physical and biological factors that may influence the distribution of the endangered winged mapleleaf mussel Quadrula fragosa (Conrad, 1835). Quantitative sampling of the mussel community was undertaken at two sites in the St. Croix River known to harbor Q fragosa. Additional searches were conducted specifically for Q. fragosa individuals. For each quantitative sample of mussels, substrate composition, water velocity and depth were assessed and mussels were identified and measured. In general, Q. fragosa does not have habitat requirements different from the rest of the mussel community, although Q. fragosa occurred in shallower areas with lower bottom current velocity compared to the overall mussel community. There was no difference in substrate composition in areas with and without Q fragosa. Mussel community density and richness were higher in areas where Q fragosa was found. The mussel community associated with Q. fragosa was not significantly different from the general mussel community in the area. However three species (Truncilla truncata, Truncilla donaciformis and Quadrula metanevra) were significantly associated with Q fragosa. Due to its association with dense and diverse mussel communities, management that benefits the entire mussel community should be effective in protecting this endangered species.