IMPACT OF ENVIRONMENT AND LAND USE HETEROGENEITY ON WEEDY CENTAUREA

Urbanization has steadily increased around the world since the advent of the industrial revolution. With more than 50% of the world's population predicted to live in urbanized areas by 2050, the rate at which the urban world is expected to interact with the biological world will increase. Particularly in the past 20 years, biologists have been pushing to better understand how the ecological interactions and evolution of organisms are responding to urban environments. A major open question in the field is what specific environmental variables (both natural and anthropogenic in nature). lead to biological change in urban environments, including for weedy and invasive species. Using the invasive species Centaurea melitensis across urbanization gradients of California, this study will explore the relationship between environmental heterogeneity and the evolution of invasive species across a dynamic urban gradient.Goal 1. Testing for trait evolution among environments that vary in anthropogenic influenceIdentifying which eco-evolutionary life history traits may be under selection in Centaurea melitensis due to specific urban stressors like water availability and the Urban Heat Island effect will be a central part of this project.Objective 1: Grow a second generation of Centaurea melitensis in a greenhouse environment and measure ecologically important traitsObjective 2: Collect leaf samples for later DNA extraction for further goalsObjective 3: Analyze the association of traits with environmental variables and prepare for publicationGoal 2. Associating trait variation with genotypic and environmental variationI will use whole genome resequencing to identify regions of the C. melitensis genome that are associated with environmental heterogeneity, and to connect those genetic variants to phenotypes.Objective 1: Extract DNA from leaf samples of Centaurea melitensisObjective 2: Sequence samples at low coverage of the whole genome (skim sequencing)Objective 3: Align sequences from Centaurea melitensis individuals to the reference genome of its sister species Centaurea solstitialisObjective 4: Perform a Genome Wide Association Study (GWAS) and Genome Environmental Analysis (GEA) to identify genes under selection in response to urbanization and environmental gradientsObjective 5: Prepare results for publicationGoal 3. Quantifying gene flow and connectivity across environmentsI will use the population genomic data described above to conduct a landscape genomic analysis of the environments that promote and hinder gene flow in C. melitensis.Objective 1: Identify population genetic structure of Centaurea melitensis across CaliforniaObjective 2: Quantify standard population genetic statistics for populations of C. melitensisObjective 3: Identify environmental variables influencing gene flow using a landscape genomics approachObjective 4: Prepare results for publication