Mercury Magnification In Riverine Food Webs In The Northern Rocky Mountains: Clark Fork River Basin, Montana, U.S.A.

At a local scale, such as the Clark Fork River Basin (CFRB), historic gold mining contributes the majority of mercury (Hg) found in the environment. Mercury enters aquatic systems in inorganic forms and is transformed to methylmercury (MeHg) by bacteria. MeHg has the ability to bioaccumulate within higher trophic levels, causing severe neurotoxic diseases and mortality. Hg concentrations observed within an aquatic food web are controlled by two factors, a source of inorganic mercury and the potential for that Hg to become methylated (methylation controlled by environmental conditions i.e.: water velocity, organic matter, etc.). A sufficient source of inorganic mercury and environmental conditions which promote Hg methylation can lead to maximum MeHg biomagnification. This study presents a comprehensive look at food web Hg biomagnification within the CFRB. Hg concentrations are characterized through blood or tissue samples from osprey, fish, and aquatic macroinvertebrates. Additionally we look at controlling Hg biomagnification factors, Hg of fine-grained sediment, percentage of wetlands and riparian land cover, and mean monthly discharge, to access the biomagnification process within the watershed and thus the Hg levels observed throughout these three trophic levels. Preliminary results show Hg levels of aquatic invertebrates have been found to be heavily influenced by the source of Hg (fine-grained sediment), while upper trophic level species exhibit a strong correlation to environmental characteristics of the sample reach

Blood-Lead Levels Of Fall Migrant Golden Eagles In West- Central Montana

Lead has long been documented as a serious environmental hazard to eagles and other predatory, opportunistic and scavenging avian species. The use of lead shotgun pellets for waterfowl hunting on federal and state lands was banned in 1991 due to lead poisoning in Bald Eagles (Haliaeetus leucocephalus), Golden Eagles (Aquila chrysaetos) and numerous waterfowl species. At that time, this was thought to be the only major source of the lead exposure. More recently, lead poisoning from ingested lead-bullet fragments and shotgun pellets has been identified as the leading cause of death in California Condors (Gymnogyps californianus), leading to the recent ban of lead ammunition within the “California Condor Recovery Zone.” Another on-going study on Common Ravens (Corvus corax) and Bald Eagles in Wyoming has shown a direct correlation between very high blood-lead levels and the on-set of rifle hunting season. Indeed, there is overwhelming evidence showing that lead toxicity is still prevalent in the environment and mounting data points to fragmented rifle bullets as the source. We sampled blood from 131 Golden Eagles captured on migration during the fall from 2006 and 2010 to quantify a suite of possible heavy metal contaminants, with an emphasis on lead

Satellite Telemetry Provides Insight into Where Western Montana Osprey Spend the Winter

During a long-term study of Osprey (Pandion haliaetus) in western Montana on demography and ecotoxicology, migratory information on several birds was collected. It is important to know where these birds migrate and spend the winter because 2/3 of their lives are spent outside Montana. Since virtually nothing was known about where these birds go when they leave the state, in 2012 and 2013 we put satellite transmitters on two families of Osprey (adults and chicks) from nests near Florence, Montana. Telemetry data show that these birds migrate south through a fairly narrow corridor to Arizona and New Mexico, but then go in different directions:  some individuals spend the winter in Texas, and others migrate to Mexico and as far south as the Nicaragua-Costa Rica border on both the Atlantic and Pacific coasts. Migration pathways of the adults were very similar for both south-bound and north-bound migrations across multiple years

METAL CONTAMINATION AND FOOD WEB CHANGES ALTER EXPOSURE TO UPPER TROPHIC LEVELS IN UPPER BLACKFOOT RIVER BASIN STREAMS, MONTANA

Reduced invertebrate abundance and diversity are common responses to metals contamination in mining-impacted streams. The resulting changes in community composition may have implications for metals accumulation and transfer through the food web. We investigated how changes in invertebrate community composition (abundance, species richness, and food web complexity) influence metals bioaccumulation and exposure risk to upper trophic levels along a contamination gradient in the upper Blackfoot River Basin, Montana. Invertebrate species richness exhibited the strongest decline with increasing sediment metals concentrations, driven by the loss of metals-sensitive taxa. These changes in invertebrate community composition resulted in a decline in the proportion of invertebrates in the scraper functional feeding group, likely influencing dietary metals exposure to the invertebrate community. Additionally, invertebrates with a strong propensity-to-drift increased with sediment contamination, potentially facilitating metals transfer to fish and higher trophic levels through predation. Using invertebrate exposure values (invertebrate abundance x metals concentrations), we found that moderately contaminated sites in our study area produced both the highest invertebrate exposure values and the highest fish tissue metals concentrations. Considering both changes in invertebrate community composition and metal concentrations is an important step towards understanding and evaluating potential toxic effects to upper trophic levels in mining-impacted streams. Note that there are several datasets associated with this article

Dataset for the article: Metal contamination and food web changes alter exposure to upper trophic levels in upper Blackfoot River basin streams, Montana

Reduced invertebrate abundance and diversity are common responses to heavy metals contamination in mining-impacted streams. The resulting changes in community composition may have implications for metals accumulation and transfer through the food web. We investigated how changes in invertebrate community composition (abundance, species richness, and food web complexity) influence metals bioaccumulation and exposure risk to upper trophic levels along a contamination gradient in the upper Blackfoot River basin, Montana. Invertebrate species richness exhibited the strongest decline with increasing sediment metals concentrations, driven by the loss of metals-sensitive taxa. These changes in invertebrate community composition resulted in a decline in the proportion of invertebrates in the scraper functional feeding group, likely influencing dietary metals exposure to the invertebrate community. Additionally, invertebrates with a strong propensity-to-drift increased with sediment contamination, potentially facilitating metals transfer to fish and higher trophic levels through predation. By using invertebrate exposure values (invertebrate abundance x metals concentrations), we found that moderately contaminated sites in our study area produced both the highest invertebrate exposure values and the highest metals concentrations in fish tissues. Our results indicate that considering both changes in invertebrate community composition and metal concentrations is an important step towards understanding and evaluating potential toxic effects to upper trophic levels in mining-impacted streams. Geographic location: Upper Blackfoot River, Montana and tributaries in the vicinity of the Upper Blackfoot Mining Complex Associated data and attachments (files available below): Water quality [Water_quality.csv] Fine sediment metals [Fine_sediment_metals.csv] Invertebrate community composition [Invertebrate_community_composition.csv] Invertebrate metals concentrations [Invertebrate_metals.csv] Fish tissue metals [Fish_metals.csv] Fish population estimate [Fish_population.csv] Site descriptions [Site_descriptions.csv] Site map [Site_map.pdf] (see Download button above

The Bird’s-Eye View Education Program: Using Bird Research To Educate The Public On The Importance Of Healthy Riparian Systems

The Upper Clark Fork River Basin (UCFRB) has been degraded by over 100 yrs of mining and smelting activities. The UCFRB is the largest contiguous complex of federal Superfund sites in the nation. Restoration and remediation efforts were initiated in the late 1980s and will continue, at a minimum, through 2030. Any restoration activity should include public education and outreach so that land-use decisions in the future do not compromise the integrity of the ecosystems that support the region. We have developed a program, the Bird’s-eye View Education Program, which integrates public education and research on the ecological health of the UCFRB. Specifically we focus on birds, inviting the public to observe research at songbird banding stations and Osprey (Pandion haliaetus) nests. Riparian-associated birds are likely to respond positively to riparian restoration activities and can be used as bio-indicators to measure success. In 2010 we operated three bird banding stations and monitored 19 Osprey nests. We captured 595 songbirds, collected 43 blood and feather samples from Osprey chicks, and served nearly 1000 participants. The program was an outstanding success and results from an assessment show that participants leave with a positive attitude toward the outdoor science experience and a general knowledge of Upper Clark Fork restoration, history, and its riparian ecosystems

Continuous presence of genetically diverse rustrela virus lineages in yellow-necked field mouse reservoir populations in northeastern Germany.

Rustrela virus (RusV; species Rubivirus strelense, family Matonaviridae) was discovered in different zoo animal species affected by fatal encephalitis. Simultaneous RusV RNA detection in multiple yellow-necked field mice (Apodemus flavicollis) suggested this rodent as a reservoir of RusV. Here, we investigated 1,264 yellow-necked field mice and sympatric other small mammals from different regions in Germany for RusV RNA using an optimized reverse transcription-quantitative polymerase chain reaction (RT-qPCR) protocol and high-throughput sequencing. The investigation resulted in the detection of RusV RNA exclusively in 50 of 396 (12.6 per cent) yellow-necked field mice but absence in other sympatric species. RT-qPCR-determined tissue distribution of RusV RNA revealed the highest viral loads in the central nervous system, with other tissues being only very rarely affected. The histopathological evaluation did not reveal any hints of encephalitis in the brains of infected animals despite the detection of viral RNA in neurons by in situ hybridization (ISH). The positive association between the body mass of yellow-necked field mice and RusV RNA detection suggests a persistent infection. Phylogenetic analysis of partial E1 and full-genome sequences showed a high diversification with at least four RusV lineages (1A-1D) in northeastern Germany. Moreover, phylogenetic and isolation-by-distance analyses indicated evolutionary processes of RusV mostly in local reservoir populations. A comparison of complete genome sequences from all detected RusV lineages demonstrated a high level of amino acid and nucleotide sequence variability within a part of the p150 peptide of the non-structural polyprotein and its coding sequence, respectively. The location of this region within the RusV genome and its genetic properties were comparable to the hypervariable region of the rubella virus. The broad range of detected RusV spillover hosts in combination with its geographical distribution in northeastern Germany requires the assessment of its zoonotic potential and further analysis of encephalitis cases in mammals. Future studies have to prove a putative co-evolution scenario for RusV in the yellow-necked field mouse reservoir

Can a River Heal Itself? Natural Attenuation of Metal Contamination in River Sediment

Sediment sampling of bed sediment from a large river contaminated by mining and smelting was used to determine rates of natural attenuation of metal concentrations. A “natural decay model” was developed from high-resolution temporal data and used to predict when restoration guidelines would be met without restoration and with various degrees of restoration success. The natural decay model estimates that in the most contaminated reaches it will take about 90 years for average concentrations of As, Cd, Cu, Pb, and Zn to fall below “probable effects concentrations” (PEC), i.e. levels above which we expect to see adverse environmental effects. At sites farther downstream, all metals will fall below PEC in <35 ± 8 years. It will take longer to reach “threshold effects concentrations” (TEC), i.e. concentrations at which no effects are expected. But, even in the most contaminated reaches, Cd, Pb, and Zn will reach TEC in <80 ± 57 years, while Cu and As will take ∼200 years. Model simulations with different levels of remediation success show that recovery is highly dependent on source reduction and how far the goal is from the basin background concentration. Furthermore, beneficial effects of restoration may be unexpectedly small: for example a likely decrease of ∼20% in the source concentration would shorten the time to reach the Cu PEC by only 13 years. We argue that conducting analyses like these can provide insight into remediation approaches and ultimately decrease the cost of restoration by identifying the role of natural attenuation in restoration design and implementation