Effects of a Low Head Dam on a Dominant Detritivore and Detrital Processing in a Headwater Stream

I evaluated the breakdown of yellow birch leaves in the presence and absence of P. gentilis using a leaf pack breakdown experiment. Leaf packs were placed in reaches above the dam where P. gentilis is present and below where it is essentially absent. I also conducted experiments to determine why P. gentilis was uncommon below the dam. Using enclosures, I evaluated whether there were differences in the survival and growth of P. gentilis in the two stream sections. I also evaluated the potential for intraguild predation by a larger caddisfly, Pycnopsyche luculenta, which is more abundant below the dam. Pycnopsyche gentilis larvae were placed in enclosures with or without P. luculenta above and below the dam; all enclosures included leaf packs. Leaf breakdown was significantly slower in the downstream section. Pycnopsyche gentilis was absent from downstream leaf packs. Detritivore diversity indices were similar for both stream sections. Calculations of P. gentilis per capita leaf ingestion in enclosures suggest that P. gentilis was primarily responsible for the higher breakdown rates in the upstream reach. My results are consistent with those of other studies that suggest the presence of P. gentilis and not diversity drives detrital breakdown in southern Appalachian streams

Diversity patterns associated with varying dispersal capabilities as a function of spatial and local environmental variables in small wetlands in forested ecosystems

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. The diversity of species on a landscape is a function of the relative contribution of diversity at local sites and species turnover between sites. Diversity partitioning refers to the relative contributions of alpha (local) and beta (species turnover) diversity to gamma (regional/landscape) diversity and can be influenced by the relationship between dispersal capability as well as spatial and local environmental variables. Ecological theory predicts that variation in the distribution of organisms that are strong dispersers will be less influenced by spatial properties such as topography and connectivity of a region and more associated with the local environment. In contrast, the distribution of organisms with limited dispersal capabilities is often dictated by their limited dispersal capabilities. Small and ephemeral wetlands are centers of biodiversity in forested ecosystems. We sampled 41 small and ephemeral wetlands in forested ecosystems six times over a two-year period to determine if three different taxonomic groups differ in patterns of biodiversity on the landscape and/or demonstrate contrasting relationships with local environmental and spatial variables. We focused on aquatic macroinvertebrates (aerial active dispersers consisting predominantly of the class Insecta), amphibians (terrestrial active dispersers), and zooplankton (passive dispersers). We hypothesized that increasing active dispersal capabilities would lead to decreased beta diversity and more influence of local environmental variables on community structure with less influence of spatial variables. Our results revealed that amphibians had very high beta diversity and low alpha diversity when compared to the other two groups. Additionally, aquatic macroinvertebrate community variation was best explained by local environmental variables, whereas amphibian community variation was best explained by spatial variables. Zooplankton did not display any significant relationships to the spatial or local environmental variables that we measured. Our results suggest that amphibians may be particularly vulnerable to losses of wetland habitat in forested ecosystems as they have high beta diversity. Consequently, the loss of individual small wetlands potentially results in local extirpations of amphibian species in forested ecosystems

Results of Treatment for Patients With Multicentric or Bilaterally Predisposed Unilateral Wilms Tumor (AREN0534): A report from the Children’s Oncology Group

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156248/2/cncr32958_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156248/1/cncr32958.pd

Trends in Stream Biodiversity Research since the River Continuum Concept

Lotic environments contain a disproportionate amount of biodiversity given their relatively small proportion of the worldwide landscape. We conducted a systematic literature search of research directed towards understanding factors that influence biodiversity in lotic habitats, published in 31 major ecological and freshwater science journals from 1981 to 2014. Our goal was to characterize emergent themes in research successes and identify important areas in need of study. We show an overwhelming taxonomic bias favoring studies of macroinvertebrates and fish, and a paucity in studies of other important groups such as bacteria and fungi. While most studies assessed habitat variables that affect diversity at a local scale, there has been a recent push to investigate regional drivers of beta and gamma diversity. Several factors were consistently found to be important drivers of diversity including local habitat type, hydrologic variables, disturbance, and stream morphometry. Others such as nutrients and chemical variables showed mixed support. Species interactions, dispersal, and evolutionary processes were rarely considered but show promise as fruitful areas for future study. We suggest that researchers should give increased attention to diversity drivers at different scales as well as take advantage of new molecular techniques to address questions regarding organismal diversity in streams

Postfledging survival of the Worthington's Marsh Wren (Cistothorus palustris griseus)

The postfledging period of a passerine bird's life is increasingly recognized as an understudied component of songbird conservation, because the habitat needs of fledglings can differ from nesting adults and survivorship during this period can substantially affect population growth rates. We studied postfledging survival of the Worthington's Marsh Wren (Cistothorus palustris griseus), a state-listed salt marsh songbird subspecies in northeastern Florida, USA, during 2016-2017. Postfledging survival was low during the first 21 d following fledging for the cohort of tracked birds (0.10; 95% confidence interval: 0.01, 0.37). The top a priori model indicated that heavier birds at the time of tagging exhibited greater survival than lighter birds, and birds from larger broods had greater survival than birds from smaller broods. Other covariates not in the top model that also influenced survival included the amount of tall-form smooth cordgrass (Spartina alterniflora) within the natal patch, which positively influenced survival, and the amount of black needlerush (Juncus roemerianus) within the natal patch, which negatively affected survival. The low rates of postfledging survival combined with low rates of nest survival reported elsewhere indicate that Worthington's Marsh Wrens in northeastern Florida require continued protection and warrant further research into management and restoration activities that will improve their habitat

Hypopigmented_Supplemental

Data includes individual bat data, measurements of white marks, recapture data, and museum specimen data

Circulating Tumor DNA as a Biomarker in Patients With Stage III and IV Wilms Tumor: Analysis From a Children\u27s Oncology Group Trial, AREN0533

PURPOSE: The utility of circulating tumor DNA (ctDNA) analyses has not been established in the risk stratification of Wilms tumor (WT). We evaluated the detection of ctDNA and selected risk markers in the serum and urine of patients with WT and compared findings with those of matched diagnostic tumor samples. PATIENTS AND METHODS: Fifty of 395 children with stage III or IV WT enrolled on Children\u27s Oncology Group trial AREN0533 had banked pretreatment serum, urine, and tumor available. Next-generation sequencing was used to detect ctDNA. Copy-number changes in 1q, 16q, and 1p, and single-nucleotide variants in serum and urine were compared with tumor biopsy data. Event-free survival (EFS) was compared between patients with and without ctDNA detection. RESULTS: ctDNA was detected in the serum of 41/50 (82%) and in the urine in 13/50 (26%) patients. Agreement between serum ctDNA detection and tumor sequencing results was as follows: 77% for 1q gain, 88% for 16q deletions, and 70% for 1p deletions, with ĸ-coefficients of 0.56, 0.74, and 0.29, respectively. Sequencing also demonstrated that single-nucleotide variants detected in tumors could be identified in the ctDNA. There was a trend toward worse EFS in patients with ctDNA detected in the serum (4-year EFS 80% 100%, = .14). CONCLUSION: ctDNA demonstrates promise as an easily accessible prognostic biomarker with potential to detect tumor heterogeneity. The observed trend toward more favorable outcome in patients with undetectable ctDNA requires validation. ctDNA profiling should be further explored as a noninvasive diagnostic and prognostic tool in the risk-adapted treatment of patients with WT

A prospective study of pediatric and adolescent renal cell carcinoma: A report from the Children’s Oncology Group AREN0321 study

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/163640/2/cncr33173.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/163640/1/cncr33173_am.pd

Kidney Preservation and Wilms Tumor Development in Children with Diffuse Hyperplastic Perilobar Nephroblastomatosis: A Report from the Children\u27s Oncology Group Study AREN0534

INTRODUCTION: Diffuse hyperplastic perilobar nephroblastomatosis (DHPLN) represents a unique category of nephroblastomatosis. Treatment has ranged from observation to multiple regimens of chemotherapy. Wilms tumors (WTs) develop in 100% of untreated patients and between 32 and 52% of treated patients. Renal preservation rates have not been previously reported. An aim of the Children\u27s Oncology Group (COG) study AREN0534 was to prospectively evaluate the efficacy of chemotherapy in preserving renal units and preventing WT development in children with DHPLN. METHODS: Patients were enrolled through the COG protocol AREN03B2 with central radiological review. DHPLN was defined as the cortical surface of the kidney being composed of hyperplastic rests, with the entire nephrogenic zone involved, and with a thick rind capping all of one or both kidneys. Treatment was with vincristine and dactinomycin (regimen EE4A), with cross-sectional imaging at weeks 6 and 12. If the patient\u27s disease was stable or decreasing, treatment was continued for 19 weeks. Renal preservation, WT development rates at 1 year, and overall survival (OS) are reported. RESULTS: Nine patients were enrolled (five females and four males), with a median age at enrollment of 10.22 months (range 2.92-29.11). One patient who was enrolled was deemed unevaluable because they did not meet the radiological criteria for DHPLN, resulting in eight evaluable patients. These eight patients had DHPLN confirmed via radiological criteria (all bilateral). Initial chemotherapy was EE4A for all eight patients, with seven of eight patients starting chemotherapy without tissue diagnosis.One patient who had an upfront partial nephrectomy was found to have DHPLN in the specimen and was subsequently treated with EE4A. All patients remained alive, with a median follow-up of 6.6 years (range 4.5-9.1). No patients were anephric; 14 of 16 kidneys were functioning (87.5%). Six of eight patients (75%) did not have WT on therapy, but two of these patients relapsed within 6 months of stopping therapy; both had favorable histology WT. One patient who was diagnosed with WT on therapy relapsed at 12 months (one of eight [12.5%]) and developed anaplastic histology. CONCLUSIONS: Chemotherapy for patients with DHPLN was effective in preserving kidney function. Five-year OS is excellent, however the ideal type and duration of chemotherapy to prevent WT development remains elusive