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  1. Abstract

    Invasive species introduction is one of the major ongoing ecological global crises. Identifying factors responsible for the success of invasive species is key for the implementation of effective management actions. The invasive filter-feeding bivalve,Corbicula, is of particular interest because it has become ubiquitous in many river basins across North America and elsewhere. Here we sampled bivalve assemblages, environmental indicators, and land cover parameters in the Ouachita highlands in southeastern Oklahoma and southwestern Arkansas, and in the Gulf Coastal Plain of Alabama to test three working models (using structural equation modeling, SEM) based on a priori scientific knowledge regardingCorbiculainvasions. Our models tested three competing hypotheses: (1) Native mussel declines are related to land use changes at the watershed level and subsequentCorbiculacolonization is a result of an empty niche; (2)Corbiculaabundance is one of the factors responsible for native mussel declines and has an interactive effect with land use change at the watershed level; (3) Native mussel declines andCorbiculasuccess are both related to land use changes at the watershed level. We found no evidence for the first two hypotheses. However, we found that environmental indicators and land cover parameters at the watershed scale were robust predictors ofCorbiculaabundance. In particular, agricultural land covermore »was positively related withCorbiculadensity. These results suggest that further improvement of conventional agricultural practices including the optimization of fertilizer delivery systems may represent an opportunity to manage this species by limiting nutrient inputs to stream ecosystems. Preservation of extensive floodplain habitats may help buffer these inputs by providing key ecosystem services including sediment and nutrient retention.

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  2. Preparing graduates to enter the workforce is a common goal of undergraduate geoscience degree programs. Determining what skills are necessary for new graduates to succeed in the workforce requires knowledge of the skills sought by employers of bachelors-level geoscientists. To investigate skills desired by employers, we systematically analyzed job advertisements retrieved from 4 search engines between May and November 2020. We used 15 search words derived from the 2018 Status of the Geoscience Workforce (AGI) report to select job advertisements that required or preferred a geoscience-based bachelor's degree. Additionally, we categorized each advertisement by industry sector based on definitions in the 2018 AGI report. Each job advertisement (n=1214) was coded to identify skills sought by the employer. An initial set of codes was based on skills identified by the Future of Undergraduate Geoscience Education project and additional emergent codes were identified during the coding process. We generated a final set of 34 codes, with definitions and examples, through an iterative coding process, checking for inter-rater reliability. Advertisements were not coded for geoscience content knowledge. The most common skills sought by employers were the ability to conduct field work, teamwork, work with computers, collect, process and interpret data, and communicate effectively,more »however, the desirability of skills varied across industry sectors. For example, teamwork skills were sought in 60% of mining sector advertisements but only 22% of oil and gas sector advertisements. Our results provide insight into the expectations of potential employers for recent graduates seeking a career in geoscience. Additionally, our results provide geoscience degree programs with critical information required to prepare undergraduates with the necessary skills to be successful in the current job market.« less