Biology subjects

Roswell, M.

Publications and source records attributed to Roswell, M..

5 recordsLinked to original sources

bioRxiv2024

Reassessing global historical R0 estimates of canine rabies

Rabies spread by domestic dogs continues to cause tens of thousands of human deaths every year in low- and middle-income countries. Nevertheless rabies is often neglected, perhaps because it has already been eliminated from high-income countries through dog vaccination. Estimates of canine rabiess intrinsic reproductive number ([R]0), a metric of disease spread, from a wide range of times and locations are relatively low (values < 2), with narrow confidence intervals. Given rabiess persistence, this consistently low and narrow range of estimates is surprising. We combined incidence data from historical outbreaks of canine rabies from around the world with in-depth contact-tracing data from Tanzania to investigate initial growth rates (r0), generation-interval distributions (G), and reproductive numbers ([R]0). We improved on earlier estimates by choosing outbreak windows algorithmically; fitting r0 using a more appropriate statistical method that accounts for decreases through time; and incorporating uncertainty from both r0 and G in our confidence intervals on[R] 0. Our[R] 0 estimates are larger than previous estimates, with wider confidence intervals. These revised[R] 0 estimates suggest that a greater level of vaccination effort will be required to eliminate rabies than previously thought, but that the level of coverage required remains feasible. Our hybrid approach for estimating[R] 0 and its uncertainty is applicable to other disease systems where researchers estimate[R] 0 by combining data-based estimates of r0 and G.

ecology↗

bioRxiv2023

Global conservation prioritization approach provides credible results at a regional scale

AimConservationists and managers must direct resources and enact measures to protect species, despite uncertainty about their present status. One approach to covering the data gap is borrowing information from data-rich species or populations to guide decisions about data-poor ones, via machine learning. Recent efforts demonstrated proof-of-concept at the global scale, leaving unclear whether similar approaches are feasible at the local and regional scales at which conservation actions most typically occur. To address this gap, we tested a global-scale predictive approach at a regional scale, using two groups of taxa. LocationState of Maryland, USA. TaxaVascular land plants and lepidopterans. MethodsUsing publicly available occurrence and biogeographic data, we trained random forest classifiers to predict the State-level conservation status of species in each of the two focal taxa. We assessed model performance with cross-validation, and explored trends in the predictions. ResultsOur models had strong discriminatory ability, accurately predicting status for species with existing status assessments. They predict that the northwestern part of Maryland, USA, which overlaps the Appalachian Mountains, harbors a higher concentration of unassessed, but likely threatened plants and lepidopterans. Our predictions track known biogeographic patterns, and unassessed species predicted as most likely threatened in Maryland were often recognized as also needing conservation in nearby jurisdictions, providing external validation to our results. Main ConclusionsWe demonstrate that a modelling approach developed for global analysis can be downscaled and credible when applied at a regional scale that is smaller than typical species ranges. We identified select unassessed plant and lepidopteran species, and the western, montane region of Maryland as priority targets for additional monitoring, assessment, and conservation. By rapidly aggregating disparate data and integrating information across taxa, models like those we used can complement traditional assessment tools and assist in prioritization for formal assessments, as well as protection.

ecology↗

bioRxiv2022

Biodiversity-ecosystem function relationships change in sign and magnitude across the Hill diversity spectrum

SummaryMotivated by accelerating anthropogenic extinctions, decades of biodiversity-ecosystem function (BEF) experiments show that ecosystem function declines with species loss from local communities. Yet, at the local scale, changes in species total and relative abundances are more common than species loss. The consensus best biodiversity measures are Hill numbers, which use a scaling parameter, {ell}, to emphasize rarer versus more common species. Shifting that emphasis captures distinct, function-relevant biodiversity gradients beyond species richness. Here, we hypothesized that Hill numbers that emphasize rare species more than richness does may distinguish large, complex, and presumably higher-functioning assemblages from smaller and simpler ones. In this study, we tested which values of {ell} produce the strongest BEF relationships in community datasets of ecosystem functions provided by wild, free-living organisms. We found that {ell} values that emphasized rare species more than richness does most often correlated most strongly with ecosystem functions. As emphasis shifted to more common species, BEF correlations were often weak and/or negative. We argue that unconventional Hill diversities that shift emphasis towards rarer species may be useful for describing biodiversity change, and that employing a wide spectrum of Hill numbers can clarify mechanisms underlying BEF relationships.

ecology↗

bioRxiv2021

Pollinator habitat plantings benefit wild, native bees, but do not necessarily favor rare species

O_LIInstalling pollinator habitat is a ubiquitous conservation tool, but little is known about which pollinator taxa require support, or which benefit from habitat installations. C_LIO_LIWe studied the response of rare and common bees to pollinator habitat enhancement. We used independent regional datasets to designate bee species as common or rare based on their rank according to one of three metrics: a) site occurrence frequency, b) local relative abundance, and c) geographic range size. We asked whether the abundance or richness of rare and common bees were greater in pollinator habitat, relative to old-field controls. Because we used an arbitrary, quantile-based cutoff to categorize species rarity, we conducted sensitivity analysis and controlled for rarity classification errors with a null model. With this null model, we determined whether rare and/or common species responded to pollinator habitat disproportionately, compared to the expectation for typical bee species. C_LIO_LIWe found that the number of individuals and of species designated as rare based on local relative abundance was greater in pollinator habitat enhancements. The number of individuals from bee species designated as rare based on site occurrence was lower in pollinator habitat enhancements, but the number of species was not clearly different between habitat types. We did not find a clear positive nor negative effect of habitat enhancement for species designated rare based on geographic range size. For all three rarity metrics, common species increased in abundance and richness in pollinator habitat relative to controls. Null models indicated that in most cases, neither rare nor common species disproportionately benefited from pollinator habitat. C_LIO_LISynthesis and Applications: Our results suggest that pollinator habitat can lead to an increase in the abundance and richness of bees, including species that are rare and that are common. However, rare species appeared to respond differently than typical species, and depending on how species were classified as rare, could display muted or even negative responses to habitat enhancement. Targeting rare species with specific floral resources or unique habitat types may lead to better outcomes for rare and threatened species. C_LI

ecology↗

bioRxiv2018

Male and female bees show large differences in floral preference

O_LIIntraspecific variation in foraging niche can drive food web dynamics and ecosystem processes. Field studies and theoretical analysis of plant-pollinator interaction networks typically focus on the partitioning of the floral community between pollinator species, with little attention paid to intraspecific variation among plants or foraging bees. In other systems, male and female animals exhibit different, cascading, impacts on interaction partners. Although the foraging ecology of male bees is little known, we expect foraging preferences to differ between male and female bees, which could strongly impact plant-pollinator interaction outcomes.\nC_LIO_LIWe designed an observational study to evaluate the strength and prevalence of sexually dimorphic foraging preferences in bees.\nC_LIO_LIWe observed bees visiting flowers in semi-natural meadows in New Jersey, USA. To detect differences in flower use against a shared background resource availability, we maximized the number of interactions observed within narrow spatio-temporal windows. To distinguish observed differences in bee use of flower species, which can reflect abundance patterns and sampling effects, from underlying differences in bee preferences, we analyzed our data with both a permutation-based null model and random effects models.\nC_LIO_LIWe found that the diets of male and female bees of the same species were often as dissimilar as the diets of bees of different species. Furthermore, we demonstrate differences in preference between male and female bees, and identify plant species that are particularly attractive to each sex. We show that intraspecific differences in preference can be robustly identified within interactions between hundreds of species, without precisely quantifying resource availability, and despite high phenological turnover.\nC_LIO_LIGiven the large differences in flower use and preference between male and female bees, ecological sex differences should be integrated into studies of bee demography, plant pollination, and coevolutionary relationships between flowers and insects.\nC_LI

ecology↗