Statistical method for testing the neutral mutation hypothesis by DNA polymorphism.

Foreword Preface Contributors Participating Institutions Acknowledgements 1. Biodiversity: Our Precious Heritage 2. Discovering Life in America: Tools and Techniques of Biodiversity Inventory 3. A Remarkable Array: Species Diversity in the United States 4. Conservation Status of U.S. Species 5. State of the States: Geographic Patterns of Diversity, Rarity, and Endemism 6. The Geography of Imperilment: Targeting Conservation towards Critical Biodiversity Areas 7. More than the Sum of the Parts: Diversity and Status of Ecological Systems 8. Leading Threats to U.S. Biodiversity: What's Threatening Imperiled Species 9. Strategies for Biodiversity Protection 10. Owning Up to Our Responsibilities: Who Owns Lands Important for Biodiversity? 11. Safeguarding Our Precious Heritage Appendix A: Extinct and missing species of the United States Appendix B: State Diversity, Endemism, and Rarity Appendix C: Kuchler Potential Natural Vegetation Types Appendix D: Principal Sources for the Natural Heritage Central Databases Literature Cited

Wisdom and Wonder@@@2000. Precious Heritage: The Status of Biodiversity in the United States

Sedimentation and turbidity are significant contributors to declines in populations of North American aquatic organisms. Impacts to lotic fauna may be expressed through pervasive alterations in local food chains beginning at the primary trophic level. Decreases in primary production are associated with increases in sedimentation and turbidity and produce negative cascading effects through depleted food availability to zooplankton, insects, freshwater mollusks, and fish. Direct effects at each trophic level are mortality, reduced physiological function, and avoidance; however, decreases in available food at trophic levels also result in depressed rates of growth, reproduction, and recruitment. Impacts of turbidity to aquatic organisms often seem inconsistent among watersheds and experiments, but this apparent difference is actually due to the lack of correlation between suspended sediment concentrations (mg/L) and units of measure (Nephelometric Turbidity Units, NTU). The use of NTU as a surrogate measurem...

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Effects of sedimentation and turbidity on lotic food webs: a concise review for natural resource managers

The sustainable use of water resources requires clear guidelines for the management of diffuse pollution inputs to rivers. Without informed guidelines, management decisions are unlikely to deliver cost-effective improvements in the quality of rivers as required by current water policy. Here, we review the evidence available for deriving improved guidelines on the loading of fine sediment to rivers based on the impact on macro-invertebrates. The relationship between macro-invertebrates and fine sediments is poorly defined. Studies of the impacts of fine sediment on macro-invertebrates have been undertaken at various scales, which has an influence on the range of responses displayed and the reliability of the results obtained; results obtained from investigations at smaller scales may not manifest at the scale required to manage rivers and vice versa. Many of the identified effects of increased loading of fine sediment on macro-invertebrates occur as a consequence of deposition on the river bed, yet many current management guidelines are based on suspended sediment targets. On this basis, existing water quality guidelines for sediment management are unlikely to be appropriate.

The impact of fine sediment on macro-invertebrates

Freshwater mussel larval parasitism of fish is unique among bivalves. The relationship is primarily phoretic rather than nutritive; only the smallest glochidia and the haustorial larva grow substantially while on the host. Growth of the smallest larvae suggests a lower functional size limit of ;150 lm for the juvenile stage. Most Ambleminae, the most diverse North American clade, infect host gills by attracting feeding fish. Many species of Pleurobemini and some Lampsilini release conglutinates of eggs and larvae that resemble host food items. Many Lampsilini and a few Quadrulini use mantle modifications to attract host fish to the female. The mantle of some Quadrulini forms a posterior chamber that holds glochidia for immediate release in response to host fish. In many Lampsilini, mantle flap lures and a protrusible marsupium promote attack by the host fish and direct extraction of glochidia from the marsupium by the host. Host extraction of glochidia from the brooding female might have favored the evolution of long-term brooding in Lampsilini because glochidia need not be released by the female to encounter the host. A remarkable derivative of the host extraction strategy evolved in Epioblasma, which catch fish between the valves and release glochidia directly to the trapped host before releasing it. Host specificity is a critical feature of the evolutionary diversification and conservation biology of Unionoida. As temporary parasites, mussels must primarily evade the innate immune responses of the host, rather than the adaptive (acquired) responses. Evolution of host specificity is associated with selective encounter of host taxa, either because of host attraction strategies or because of dominance of particular host species in the habitat. The intricate relationships between mussels and fish are easily disrupted and, thus, contribute to the imperilment of many mussel species, yet they also fascinate us and compel conservation efforts.

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Adaptations to host infection and larval parasitism in Unionoida

The decline in freshwater mussel populations in many river basins throughout North America has been attributed, in part, to land-use modifications that cause changes in sediment regimes However, t

Sediment, Land Use, and Freshwater Mussels: Prospects and Problems

Freshwater mussels (unionids) are increasingly recognized as important providers of ecosystem services, yet are among the most endangered fauna in the world. Because unionids are generally sessile and require specific fish hosts for development and dispersal, they are particularly vulnerable to habitat degradation. Surprisingly, little is known about the distribution of genetic diversity in freshwater mussels and this gap has a negative impact on taxonomy, monitoring, conservation and ecological research in these species. Here, we focus on western North American Anodonta, one of only three genera known to exist in this broad landscape and which contains three highly divergent lineages. We describe phylogeographical subdivision in the most widespread and diverse of these lineages, which includes Anodonta californiensis and Anodonta nuttalliana and occurs from Canada to Mexico. Using mitochondrial and nuclear data, we found that genetic structuring within this clade is inconsistent with morphologically based species designations, but instead follows patterns of vicariance among major hydrogeologic basins. Furthermore, there was a strong tendency for population diversity within drainage systems to increase downstream, implying greater habitat or host fish availability in this direction. Microsatellite results indicated that sampling locations were all genetically distinct, even at short distances. Many of our sample populations showed evidence of a recent demographic bottleneck, although this effect seemed to be very local and not drainage or basin-specific. This study provides a foundation for the establishment of appropriate management units and future research on adaptive differentiation and host fish relationships.

Genetic structuring in the freshwater mussel Anodonta corresponds with major hydrologic basins in the western United States

The surprising diversity and recent dramatic decline of freshwater mussels in North America have been well documented, although inventory efforts to date have been concentrated in the eastern United States. Unlike their eastern counterparts, western freshwater mussels have received comparatively little attention. The accurate identity of western lineages is a necessary component for future inventory, monitoring, and ecological work involving these taxa. Here we initiate a study involving the most speciose genus (Anodonta) in western North America, incorporating information about type localities and type specimen morphology and describing the discovery of three highly divergent lineages among four western Anodonta species. In a limited phylogenetic analysis, we find (1) that A. californiensis/nuttalliana and A.oregonensis/kennerlyi are distinct, highly divergent clades, and (2) that A. beringiana is more closely allied with A. woodiana, an Asian species, than either of the other two western North American clades. We were largely unable to resolve the placement of these three clades with respect to other anodontines, and suggest the need for a broader phylogenetic framework. We recommend, however, that the existence of these three deeply divergent groups be considered in the development of regional monitoring, conservation and research plans despite the taxonomic uncertainty.

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Three deeply divided lineages of the freshwater mussel genus Anodonta in western North America

The reproductive biology, glochidial morphology and recruitment of the federally endangered shinyrayed pocketbook, Lampsilis subangulata, were studied from May 1995 to July 1996 in the Flint River system, Georgia. Gravid female L. subangulata were found nine months of the year. On 19 May 1995, a L. subangulata was discovered releasing a superconglutinate, the first record confirming that this species used this specialized reproductive strategy. Superconglutinate release occurred from late May to mid-July in water temperatures ranging from 20.0 to 23.5 C. Laboratory experiments indicated that two fish species served as primary hosts, the spotted bass (Micropterus punctulatus) and largemouth bass (M. salmoides). Secondary host fish included the eastern mosquitofish (Gambusia holbrooki), guppy (Poecilia reticulata) and bluegill (Lepomis macrochirus). The glochidial morphology of L. subangulata was similar to other lampsiline species. Using quantitative survey methods, no evidence of recent juvenile ...

Reproductive Biology and Juvenile Recruitment of the Shinyrayed Pocketbook, Lampsilis Subangulata (Bivalvia: Unionidae) in the Gulf Coastal Plain

The reproductive biology of the California floater (Anodonta californiensis), western ridged mussel (Gonidea angulata) and western pearlshell (Margaritifera falcata) was studied in the Middle Fork John Day River from May 2005 to July 2011. Anodonta californiensis was gravid from early May to late July. Mature A. californiensis glochidia were hooked, rust-colored, sub-triangulate, averaged 276 µm in length, and were similar in size to other glochidia of the genus Anodonta. Gravid G. angulata were found only in June. Mature G. angulata glochidia were hookless, white, sub-round, and averaged 171 µm in length, similar to the oval pigtoe (Pleurobema pyriforme). Margaritifera falcata were gravid in early May. Mature M. falcata glochidia were hookless, white, sub-round, and averaged 55 µm in length, a size and shape similar to the spectacle case (Cumberlandia monodonta). Anodonta californiensis glochidia were found attached to six wild-caught fish species from early June to late July. In contrast, G. an...

https://bioone.org/journals/Northwest-Science/volume-87/issue-1/046.087.0105/Reproductive-Biology-of-Anodonta-californiensis-Gonidea-angulata-and-Margaritifera-falcata/10.3955/046.087.0105.pdf

Reproductive Biology of Anodonta californiensis, Gonidea angulata, and Margaritifera falcata (Bivalvia: Unionoida) in the Middle Fork John Day River, Oregon

Jayne C. Brim Box

Papers

Sediment, Land Use, and Freshwater Mussels: Prospects and Problems

Genetic structuring in the freshwater mussel Anodonta corresponds with major hydrologic basins in the western United States

Three deeply divided lineages of the freshwater mussel genus Anodonta in western North America

Reproductive Biology and Juvenile Recruitment of the Shinyrayed Pocketbook, Lampsilis Subangulata (Bivalvia: Unionidae) in the Gulf Coastal Plain

Reproductive Biology of Anodonta californiensis, Gonidea angulata, and Margaritifera falcata (Bivalvia: Unionoida) in the Middle Fork John Day River, Oregon