Linking genotypic diversity within Solidago altissima to communities and ecosystems

For almost two decades, ecological studies have addressed the importance of plant species diversity for associated animal diversity and the functioning of ecosystems. Recently, a burgeoning focus of research in ecology is on how population-level diversity scales up to affect patterns and processes at the community- and ecosystem-level. In this dissertation, I present results from a series of common garden experiments in which I manipulated genotypic diversity of tall goldenrod (Solidago altissima) to address a suite of questions about how intraspecific variation in a dominant old-field plant species shapes communities of associated arthropods and ecosystem processes. In these studies, I found that host-plant genotypic diversity had non-additive effects on insect herbivore and predator diversity and that incorporating temporal dynamics into community genetics studies is essential for predicting how different community members perceive and respond to genetically variable host-plant traits. I found that variation among host-plant genotypes had strong effects on the diversity and composition of foliage-based arthropods, but only weak effects on litter-based microarthropods. Additionally, I found strong effects of instraspecific genetic variation in goldenrod functional traits on primary productivity, litter quality, decomposition rate, nitrogen release, and community invasibility. Together, my results indicate that within-species variation is an important, but all to [sic] often overlooked, influence on the structure and dynamics of communities and ecosystems

Multiple plant traits shape the genetic basis of herbivore community assembly

1. Community genetics research has posited a genetic basis to the assembly of ecological communities. For arthropod herbivores in particular, there is strong support that genetic variation in host plants is a key factor shaping their diversity and composition. However, the specific plant phenotypes underlying herbivore responses remain poorly explored for most systems. 2. We address this knowledge gap by examining the influence of both genetic and phenotypic variation in a dominant host-plant species, Salix hookeriana, on its associated arthropod herbivore community in a common garden experiment. Specifically, we surveyed herbivore responses among five different arthropod feeding guilds to 26 distinct S. hookeriana genotypes. Moreover, we quantified the heritability of a suite of plant traits that determine leaf quality (e.g. phenolic compounds, trichomes, specific leaf area, C : N) and whole-plant architecture, to identify which traits best accounted for herbivore community responses to S. hookeriana genotype. 3. We found that total herbivore abundance and community composition differed considerably among S. hookeriana genotypes, with strong and independent responses of several species and feeding guilds driving these patterns. We also found that leaf phenolic chemistry displayed extensive heritable variation, whereas leaf physiology and plant architecture tended to be less heritable. Of these traits, herbivore responses were primarily associated with leaf phenolics and plant architecture; however, different herbivore species and feeding guilds were associated with different sets of traits. Despite our thorough trait survey, plant genotype remained a significant predictor of herbivore responses in most trait association analyses, suggesting that unmeasured host-plant characteristics and/or interspecific interactions were also contributing factors. 4. Taken together, our results support that the genetic basis of herbivore community assembly occurs through a suite of plant traits for different herbivore species and feeding guilds. Still, identifying these phenotypic mechanisms requires measuring a broad range of plant traits and likely further consideration of how these traits affect interspecific interactions.Fil: Barbour, Matthew A.. University Of British Columbia; CanadáFil: Rodriguez Cabal, Mariano Alberto. University Of British Columbia; Canadá. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; Argentina. Universidad Nacional del Comahue; ArgentinaFil: Wu, Elizabeth T.. Humboldt State University; Estados UnidosFil: Julkunen Tiitto, Riitta. University of Eastern Finland; FinlandiaFil: Ritland, Carol E.. University Of British Columbia; CanadáFil: Miscampbell, Allyson E.. University Of British Columbia; CanadáFil: Jules, Erik S.. Humboldt State University; Estados UnidosFil: Crutsinger, Gregory M.. University Of British Columbia; Canad

Non-Additive Effects of Genotypic Diversity Increase Floral Abundance and Abundance of Floral Visitors

Background: In the emerging field of community and ecosystem genetics, genetic variation and diversity in dominant plant species have been shown to play fundamental roles in maintaining biodiversity and ecosystem function. However, the importance of intraspecific genetic variation and diversity to floral abundance and pollinator visitation has received little attention. Methodology/Principal Findings: Using an experimental common garden that manipulated genotypic diversity (the number of distinct genotypes per plot) of Solidago altissima, we document that genotypic diversity of a dominant plant can indirectly influence flower visitor abundance. Across two years, we found that 1) plant genotype explained 45 % and 92 % of the variation in flower visitor abundance in 2007 and 2008, respectively; and 2) plant genotypic diversity had a positive and non-additive effect on floral abundance and the abundance of flower visitors, as plots established with multiple genotypes produced 25 % more flowers and received 45 % more flower visits than would be expected under an additive model. Conclusions/Significance: These results provide evidence that declines in genotypic diversity may be an important but little considered factor for understanding plant-pollinator dynamics, with implications for the global decline in pollinators due t

THE FUTURE OF UAVS IN ECOLOGY: AN INSIDER PERSPECTIVE FROM THE SILICON VALLEY DRONE INDUSTRY

N/AThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Data from: Spartina alterniflora genotypic identity affects plant and consumer responses in an experimental marsh community

1. Competition and herbivory are ubiquitous processes known to interactively shape plant performance, distribution and community assembly. Likewise, plant genetic variation and associated trait differences can impact both plant-plant and plant-herbivore interactions individually, yet few studies have explored these interactions simultaneously. 2. Salt marsh communities are an ideal system to study these questions, as they are dominated along the Atlantic and Gulf coasts of the United States by a foundation plant species, Spartina alterniflora, with high levels of genetically-based trait variation. Furthermore, consumer pressure and plant competitors are known to influence both the distribution and production of Spartina. We manipulated Spartina genetic identity, neighbor identity (needlerush, Juncus roemerianus), and consumer presence (snail, Littoraria irrorata) in a one-year field experiment in St. Joseph Bay, FL to test how the strength and direction of neighbor and consumer interactions vary by plant genotype. 3. Consumer effects on Spartina were generally stronger and more variable than those of the plant neighborhood, and these effects were generally consistent across Spartina genotypes. However, genotype-specific variation in morphology, phenology, and palatability significantly influenced both consumer and neighbor responses to Spartina: the consumer Littoraria was more likely to climb palatable Spartina genotypes, and neighboring Juncus had shorter stems in the presence of highly productive Spartina genotypes. 4. Synthesis. Our results add to the growing list of examples highlighting the role of intraspecific variation in species interactions, and suggest that variation in these interactions may promote the maintenance of plant genetic variation and community composition

Local and latitudinal variation in abundance: the mechanisms shaping the distribution of an ecosystem engineer

Ecological processes that determine the abundance of species within ecological communities vary across space and time. These scale-dependent processes are especially important when they affect key members of a community, such as ecosystem engineers that create shelter and food resources for other species. Yet, few studies have examined the suite of processes that shape the abundance of ecosystem engineers. Here, we evaluated the relative influence of temporal variation, local processes, and latitude on the abundance of an engineering insect—a rosette-galling midge, Rhopalomyia solidaginis (Diptera: Cecidomyiidae). Over a period of 3–5 years, we studied the density and size of galls across a suite of local experiments that manipulated genetic variation, soil nutrient availability, and the removal of other insects from the host plant, Solidago altissima (tall goldenrod). We also surveyed gall density within a single growing season across a 2,300 km latitudinal transect of goldenrod populations in the eastern United States. At the local scale, we found that host-plant genotypic variation was the best predictor of rosette gall density and size within a single year. We found that the removal of other insect herbivores resulted in an increase in gall density and size. The amendment of soil nutrients for four years had no effect on gall density, but galls were smaller in carbon-added plots compared to control and nitrogen additions. Finally, we observed that gall density varied several fold across years. At the biogeographic scale, we observed that the density of rosette gallers peaked at mid-latitudes. Using meta-analytic approaches, we found that the effect size of time, followed by host-plant genetic variation and latitude were the best predictors of gall density. Taken together, our study provides a unique comparison of multiple factors across different spatial and temporal scales that govern engineering insect herbivore density

Appendix B. Monte Carlo simulations to test for nonadditivity.

Monte Carlo simulations to test for nonadditivity

Appendix A. Natural history information and site description.

Natural history information and site description