Project Safe Flight: Making New York Safe for Migratory Birds

More than 100 species of migratory birds pass through New York City during spring and fall migrations. Located at the nexus of several migratory routes, New York City’s tall buildings and reflective glass pose a serious threat to over 100 species of migratory birds. Since 1997, NYC Audubon has led Project Safe Flight (PSF), a volunteer-based citizen-science project, with the goal of monitoring and mitigating bird collisions. We examined 16 years of PSF data, during which volunteers collected over 6,000 birds of 126 different species. The top two species, White-throated Sparrow and Common Yellowthroat, make up 23% of all collisions. The fall migration has a higher average number of collisions than spring. Distinct phenological trends in species composition are apparent, with American Woodcock making up the majority of early spring collisions and Dark-eyed Junco being the most common in late fall. Because birds may be overlooked by volunteers or be taken by scavengers or maintenance crews after collisions, we performed a persistence study and found that the recovery of bird carcasses was highly variable between sites. This ongoing study is important in developing a database of bird collisions to help elucidate and reduce the causes of urban bird collisions

Microbial Community Field Surveys Reveal Abundant Pseudomonas Population in Sorghum Rhizosphere Composed of Many Closely Related Phylotypes

While the root-associated microbiome is typically less diverse than the surrounding soil due to both plant selection and microbial competition for plant derived resources, it typically retains considerable complexity, harboring many hundreds of distinct bacterial species. Here, we report a time-dependent deviation from this trend in the rhizospheres of field grown sorghum. In this study, 16S rRNA amplicon sequencing was used to determine the impact of nitrogen fertilization on the development of the root-associated microbiomes of 10 sorghum genotypes grown in eastern Nebraska. We observed that early rhizosphere samples exhibit a significant reduction in overall diversity due to a high abundance of the bacterial genus Pseudomonas that occurred independent of host genotype in both high and low nitrogen fields and was not observed in the surrounding soil or associated root endosphere samples. When clustered at 97% identity, nearly all the Pseudomonas reads in this dataset were assigned to a single operational taxonomic unit (OTU); however, exact sequence variant (ESV)-level resolution demonstrated that this population comprised a large number of distinct Pseudomonas lineages. Furthermore, single-molecule long-read sequencing enabled high-resolution taxonomic profiling revealing further heterogeneity in the Pseudomonas lineages that was further confirmed using shotgun metagenomic sequencing. Finally, field soil enriched with specific carbon compounds recapitulated the increase in Pseudomonas, suggesting a possible connection between the enrichment of these Pseudomonas species and a plant-driven exudate profile

Microbial Community Field Surveys Reveal Abundant Pseudomonas Population in Sorghum Rhizosphere Composed of Many Closely Related Phylotypes

While the root-associated microbiome is typically less diverse than the surrounding soil due to both plant selection and microbial competition for plant derived resources, it typically retains considerable complexity, harboring many hundreds of distinct bacterial species. Here, we report a time-dependent deviation from this trend in the rhizospheres of field grown sorghum. In this study, 16S rRNA amplicon sequencing was used to determine the impact of nitrogen fertilization on the development of the root-associated microbiomes of 10 sorghum genotypes grown in eastern Nebraska. We observed that early rhizosphere samples exhibit a significant reduction in overall diversity due to a high abundance of the bacterial genus Pseudomonas that occurred independent of host genotype in both high and low nitrogen fields and was not observed in the surrounding soil or associated root endosphere samples. When clustered at 97% identity, nearly all the Pseudomonas reads in this dataset were assigned to a single operational taxonomic unit (OTU); however, exact sequence variant (ESV)-level resolution demonstrated that this population comprised a large number of distinct Pseudomonas lineages. Furthermore, single-molecule long-read sequencing enabled high-resolution taxonomic profiling revealing further heterogeneity in the Pseudomonas lineages that was further confirmed using shotgun metagenomic sequencing. Finally, field soil enriched with specific carbon compounds recapitulated the increase in Pseudomonas, suggesting a possible connection between the enrichment of these Pseudomonas species and a plant-driven exudate profile

The Role of Urbanization and Community Assembly on the Microbial Defense Mechanisms of Plethodon cinereus

The current global mass extinction of amphibians, driven by both habitat degradation and wildlife disease (Batrachochytrium dendrobatidis, Bd), has resulted in the extinction of nearly 100 species and threatened approximately 40% of the remaining 7000 species. Habitat degradation, of which the most extreme form is urbanization, which involves increasing levels of impervious surfaces, man-made structures, and human populations, can shift soil characteristics altering microbial composition. Such environmental changes ultimately shift taxonomic and functional diversity of bacterial species. Given that the amphibian cutaneous microbiome is supplied with microbial colonists from the soil community, host health and disease protection can be compromised with changes in the soil environment. For the bacteria that successfully colonize amphibian skin, their dominance in the community will be further regulated by intra- and interspecific interactions on the host as they compete for resources and exchange antibiotic metabolites. This dissertation combines ecological theory and applied molecular biology to elucidate the mechanisms behind variation in microbiome composition, structure, and function. Further it explores the factors most important for guiding assembly of the amphibian microbiome and how variation in these processes might affect disease resistance. Overall, this research provides essential insights into the ecological dynamics of host-associated microbiomes, the use of probiotics in wildlife disease management, as well as the processes driving variation in community structure and diversity over space and time

Exploring the roles of microbes in facilitating plant adaptation to climate change.

Plants benefit from their close association with soil microbes which assist in their response to abiotic and biotic stressors. Yet much of what we know about plant stress responses is based on studies where the microbial partners were uncontrolled and unknown. Under climate change, the soil microbial community will also be sensitive to and respond to abiotic and biotic stressors. Thus, facilitating plant adaptation to climate change will require a systems-based approach that accounts for the multi-dimensional nature of plant-microbe-environment interactions. In this perspective, we highlight some of the key factors influencing plant-microbe interactions under stress as well as new tools to facilitate the controlled study of their molecular complexity, such as fabricated ecosystems and synthetic communities. When paired with genomic and biochemical methods, these tools provide researchers with more precision, reproducibility, and manipulability for exploring plant-microbe-environment interactions under a changing climate

Poisson hurdle model-based method for clustering microbiome features

Motivation: High-throughput sequencing technologies have greatly facilitated microbiome research and have generated a large volume of microbiome data with the potential to answer key questions regarding microbiome assembly, structure and function. Cluster analysis aims to group features that behave similarly across treatments, and such grouping helps to highlight the functional relationships among features and may provide biological insights into microbiome networks. However, clustering microbiome data are challenging due to the sparsity and high dimensionality. Results: We propose a model-based clustering method based on Poisson hurdle models for sparse microbiome count data. We describe an expectation–maximization algorithm and a modified version using simulated annealing to conduct the cluster analysis. Moreover, we provide algorithms for initialization and choosing the number of clusters. Simulation results demonstrate that our proposed methods provide better clustering results than alternative methods under a variety of settings. We also apply the proposed method to a sorghum rhizosphere microbiome dataset that results in interesting biological findings

Microbial Community Field Surveys Reveal Abundant Pseudomonas Population in Sorghum Rhizosphere Composed of Many Closely Related Phylotypes.

While the root-associated microbiome is typically less diverse than the surrounding soil due to both plant selection and microbial competition for plant derived resources, it typically retains considerable complexity, harboring many hundreds of distinct bacterial species. Here, we report a time-dependent deviation from this trend in the rhizospheres of field grown sorghum. In this study, 16S rRNA amplicon sequencing was used to determine the impact of nitrogen fertilization on the development of the root-associated microbiomes of 10 sorghum genotypes grown in eastern Nebraska. We observed that early rhizosphere samples exhibit a significant reduction in overall diversity due to a high abundance of the bacterial genus Pseudomonas that occurred independent of host genotype in both high and low nitrogen fields and was not observed in the surrounding soil or associated root endosphere samples. When clustered at 97% identity, nearly all the Pseudomonas reads in this dataset were assigned to a single operational taxonomic unit (OTU); however, exact sequence variant (ESV)-level resolution demonstrated that this population comprised a large number of distinct Pseudomonas lineages. Furthermore, single-molecule long-read sequencing enabled high-resolution taxonomic profiling revealing further heterogeneity in the Pseudomonas lineages that was further confirmed using shotgun metagenomic sequencing. Finally, field soil enriched with specific carbon compounds recapitulated the increase in Pseudomonas, suggesting a possible connection between the enrichment of these Pseudomonas species and a plant-driven exudate profile