The Effect of Climate-Driven Phenological Shifts on Plant-Pollinator Interactions and Plant and Pollinator Reproductive Success

Plants and pollinators are shifting their annual bloom periods and emergence dates (i.e., phenologies) in response to ongoing climate-warming. However, the magnitude of phenological shifts can be species-specific, causing concern that unequal responses will disrupted plantpollinator interactions (i.e., phenological mismatches) and create novel community composition throughout the growing season. The effects of phenological mismatches on plants and pollinators remains unknown, preventing conservation strategies that pinpoint the most vulnerable species. The goal of this study was to investigate the effects of phenological shifts on plants and bees by manipulating plant-bee community composition within mesh-sided enclosures (mesocosms). Plantbee communities were assembled following a factorial design based on phenologies (i.e., spring vs. summer blooming plants and spring vs. summer emerging bees), allowing a comparison of plant-bee interactions and reproductive success within ‘phenologically matched’ communities (e.g., spring blooming plants with spring emerging bees) and ‘phenologically mismatched’ communities (e.g., spring blooming plants with summer emerging bees). Preliminary results suggest that interaction frequency was similar between ‘mismatched’ and ‘matched’ communities, implying that plants and bees can compensate for interactions disrupted by phenological mismatches. Currently, I am processing the reproductive data from both plants (i.e., seed set) and bees (i.e, total offspring) to determine if interaction frequency is indicative of reproductive success

Life History Traits as Mediators of Solitary Bee Responses To Climate-Warming

Climate-warming is uncoupling plant-pollinator interactions by causing species-specific shifts in seasonal flowering periods and pollinator activity times (i.e. phenologies). The mechanisms mediating pollinator responses to warming are poorly understood, preventing conservation professionals from identifying the most at-risk species and limiting our understanding of the potential effects of climate warming on plant-pollinator communities. The goal of this study was to experimentally investigate whether solitary bee (Hymenoptera spp.) overwintering life stages influence phenological responses to climate-warming. Climate-controlled growth chambers where used to manipulate the temperature bees experienced while developing and overwintering. Results suggest that different physiological constraints associated with overwintering in the prepupal life stage compared to the adult life stage may influence how solitary bees respond to climate-warming in predictable ways. Bees that overwinter as adults may be more prone to phenological mismatches in the spring, while bees that overwinter as prepupae may be more prone to phenological mismatches in mid summer. In addition, the phenologies of bees that overwinter as adults may be converging with the phenologies of bees that overwinter as prepupae, causing reduced pollinator abundance during late summer and altering competition among bees for nectar and pollen during early summer. This work demonstrates that life history traits of bees may mediate their responses to climate-warming. These findings contribute to a better understanding of the effects of climate warming on pollinator species, with implications for preserving pollination services in Montana, as well as informing future studies investigating the effects of climate warming on plants and pollinators

Wildfire disturbance and productivity as drivers of plant species diversity across spatial scales

Wildfires influence many temperate terrestrial ecosystems worldwide. Historical environmental heterogeneity created by wildfires has been altered by human activities and will be impacted by future climate change. Our ability to predict the impact of wildfire-created heterogeneity on biodiversity is limited because few studies have investigated variation in community composition (beta-diversity) in response to fire. Wildfires may influence beta-diversity through several ecological mechanisms. First, high-severity fires may decrease beta-diversity by homogenizing species composition when they create landscapes dominated by disturbance-tolerant or rapidly colonizing species. In contrast, mixed-severity fires may increase beta-diversity by creating mosaic landscapes containing habitats that support species with differing environmental tolerances and dispersal traits. Moreover, the effects of fire severity on beta-diversity may change depending on site conditions. Disturbance is hypothesized to increase local species richness at higher productivity and decrease local species richness at lower productivity, a process that can have important, but largely unexamined, consequences on beta-diversity in fire-prone ecosystems. We tested these hypotheses by comparing patterns of beta-diversity and species richness across 162 plant communities in three sites that span a large-scale gradient in climate and productivity in the Northern Rockies of Montana. Within each site, we used spatially explicit fire-severity data to stratify sampling across unburned forests and forests burned with mixed- and high-severity wildfires. We found that beta-diversity (community dispersion) of forbs was higher in mixed-severity compared to high-severity fire, regardless of productivity. Counter to our predictions, local species richness of forbs was higher in burned landscapes compared to unburned landscapes at the low-productivity site, but lower in burned landscapes at the high-productivity site. This pattern may be explained by rapid regeneration of woody plants after fire in high-productivity forests. Moreover, forbs and woody plants had disproportionately higher overall species richness in mixed-severity fire compared to high-severity fire, but only at the low-productivity site. These patterns suggest that mixed-severity fires promote higher landscape-level biodiversity in low-productivity sites by increasing species turnover across landscapes with a diverse mosaic of habitats. Our study illustrates the importance of understanding the mechanisms by which patterns of wildfire severity interact with environmental gradients to influence patterns of biodiversity across spatial scales

Plant-pollinator interactions over 120 years: loss of species, co-occurrence, and function

Using historic data sets, we quantified the degree to which global change over 120 years disrupted plant-pollinator interactions in a temperate forest understory community in Illinois, USA. We found degradation of interaction network structure and function and extirpation of 50% of bee species. Network changes can be attributed to shifts in forb and bee phenologies resulting in temporal mismatches, nonrandom species extinctions, and loss of spatial co-occurrences between extant species in modified landscapes. Quantity and quality of pollination services have declined through time. The historic network showed flexibility in response to disturbance; however, our data suggest that networks will be less resilient to future changes

Validation of suitable internal control genes for expression studies in aging.

Quantitative data from experiments of gene expression are often normalized through levels of housekeeping genes transcription by assuming that expression of these genes is highly uniform. This practice is being questioned as it becomes increasingly clear that the level of housekeeping genes expression may vary considerably in certain biological samples. To date, the validation of reference genes in aging has received little attention and suitable reference genes have not yet been defined. Our aim was to evaluate the expression stability of frequently used reference genes in human peripheral blood mononuclear cells with respect to aging. Using quantitative RT-PCR, we carried out an extensive evaluation of five housekeeping genes, i.e. 18s rRNA, ACTB, GAPDH, HPRT1 and GUSB, for stability of expression in samples from donors in the age range 35-74 years. The consistency in the expression stability was quantified on the basis of the coefficient of variation and two algorithms termed geNorm and NormFinder. Our results indicated GUSB be the most suitable transcript and 18s the least for accurate normalization in PBMCs. We also demonstrated that aging is a confounding factor with respect to stability of 18s, HPRT1 and ACTB expression, which were particularly prone to variability in aged donors

Negative density dependence mediates biodiversity–productivity relationships across scales

Regional species diversity generally increases with primary productivity whereas local diversity–productivity relationships are highly variable. This scale-dependence of the biodiversity–productivity relationship highlights the importance of understanding the mechanisms that govern variation in species composition among local communities, which is known as β-diversity. Hypotheses to explain changes in β-diversity with productivity invoke multiple mechanisms operating at local and regional scales, but the relative importance of these mechanisms is unknown. Here we show that changes in the strength of local density-dependent interactions within and among tree species explain changes in β-diversity across a subcontinental-productivity gradient. Stronger conspecific relative to heterospecific negative density dependence in more productive regions was associated with higher local diversity, weaker habitat partitioning (less species sorting), and homogenization of community composition among sites (lower β-diversity). Regional processes associated with changes in species pools had limited effects on β-diversity. Our study suggests that systematic shifts in the strength of local interactions within and among species might generally contribute to some of the most prominent but poorly understood gradients in global biodiversity

Checklist of bees (Hymenoptera: Apoidea) from small diversified vegetable farms in south-western Montana

Background Over three years (2013-2015), we sampled bees using nets and bowl traps on four diversified vegetable farms in Gallatin County, Montana, USA, as part of a study evaluating the use of wildflower strips for supporting wild bees and crop pollination services on farmlands (Delphia et al. In prep). We document 202 species and morphospecies from 32 genera within five families, of which 25 species represent the first published state records for Montana. This study increases our overall understanding of the distribution of wild bee species associated with agroecosystems of the northern US Rockies, which is important for efforts aimed at conserving bee biodiversity and supporting sustainable crop pollination systems on farmlands. New information We provide a species list of wild bees associated with diversified farmlands in Montana and increase the number of published bee species records in the state from 374 to at least 399. The list includes new distributional records for 25 wild bee species, including two species that represent considerable expansions of their known ranges, Lasioglossum (Dialictus) clematisellum (Cockerell 1904) with previously published records from New Mexico, Arizona, California and Utah and Melissodes (Eumelissodes) niveus Robertson 1895 which was reported to range from New York to Minnesota and Kansas, south to North Carolina, Alabama and Mississippi

Increasing Invasive Plant Pest Early Detection Through Interagency First Detector Education

The Collaborative and Enhanced First Detector Training program has expanded invasive species detection efforts by teaching participants to scout for, identify, and submit suspect exotic species samples. Workshops were delivered to agriculture professionals, master gardeners, and other Extension audiences. Topics included introduction pathways, regulatory agency procedures, identification of invasive pests or pathogens, monitoring procedures, and sample submission. Survey data indicated the intent of participants to augment detection efforts and the efficacy of Extension workshops in improving participants\u27 perceptions of government agencies. Respondents perceived increases in knowledge related to particular invasive species, identification of potential future invaders, and sample submission. Other implications related to Extension programming on invasive species education are discussed

A review of iron carbonate (FeCO₃) formation in the oil and gas industry

This paper reviews the information in the literature relating to FeCO₃ formation in the context of oil and gas production. Numerous factors which influence the kinetics, physical properties and protective nature of FeCO₃ are considered in addition to a review of semi-empirical models developed to predict precipitation/corrosion layer accumulation rate. The limitations of current models are discussed and the challenges of conducting deposition studies onto steel surfaces in a controlled environment using laboratory based techniques are also reviewed. Finally, more recently employed experimental techniques are considered in their potential to provide a further understanding of FeCO₃ and mixed carbonate kinetics