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Multisite, course-based undergraduate research experiences (CUREs) in the Ecological Research as Education Network (EREN) were assessed for impacts on student learning of collaborative science skills using a survey that could serve as a starting point for a validated assessment instrument for multisite CUREs. Pretests/posttests were administered across multiple courses and institutions, capturing effects of diverse EREN projects and pedagogies on collaborative knowledge. Students' scientific collaboration and data management skills improved most in small, upper-level courses. The amount of EREN content in a course was positively associated with posttest scores for 60 to 86 percent of assessment survey questions. However, no learning gains were seen for some questions, and some cases of low competency and effects of timing and place of assessment testing were observed in student scores. EREN CUREs need further development to maximize their potential.

Question To what extent are species, including native and non-native species, influencing one another's distribution and abundance in the herb layer of a Minnesota oak woodland? Location Oak woodland succeeding into a more mesic forest, on bluffland of the Mississippi River, east-central Minnesota. Methods We collected plant composition and species cover data in 182 1.0 × 0.5 m quadrats regularly spaced on a 6-ha study grid in the oak woodland. We also recorded slope, slope position, aspect, elevation and photosynthetically active radiation (PAR) at each quadrat. Results Presence and abundance of other plant species, topographic variables and light availability explained only a small portion of the variation (5-19%) in the distribution and abundance of individual species. The most common strongest predictor of cover for the ten most common species was species richness, with the association being positive. The non-native species, garlic mustard ( Alliaria petiolata) exhibited the strongest positive association with species richness. Only one of the 45 pair-wise comparisons of the ten species resulted in a negative relationship between the species. Abundance and distribution of two species were associated with topographic features, but this accounted for much less of the variation in abundance than did species richness. Conclusion We found little evidence that competition or any other interactions among common herb layer species, including the non-native Alliaria petiolata, play an important role in determining the abundance and the distribution of herb layer species in this oak woodland. Topographic factors may explain a small amount of the distribution and abundance patterns of a few species. But, for the most part, species are more likely to be present when other species are present, suggesting that they are simply establishing in microsites favourable to plants in general. [ABSTRACT FROM AUTHOR]

Garlic mustard, Alliaria petiolata (M. Bieb.) Cavara & Grande, is an introduced biennial forb that has commonly been referred to as highly invasive and as having substantial negative effects on other plants in the eastern deciduous forests of North America. However, several recent studies have documented only modest effects on other plant species, raising questions as to the extent of the threat really posed by A. petiolata. Alliaria petiolata often exhibits an alternating two-year life-history cycle, with high rosette years alternating with high flowering stem years. It has been proposed that this cycle is partly driven by intraspecific competition between the stems and the rosettes. In a two-year study, we extensively sampled A. petiolata in a Minnesota woodland at two spatial scales, including 6.5 km of belt transects in a 6.8 ha study grid (20 x 20 m cells) and 90 small sampling quadrats (1.0 x 0.5 m) within the grid. At the large scale, we compared seed bank abundance and diversity of other herbaceous plants with A. petiolata abundance. Using the monitoring data we also investigated whether this population was exhibiting an alternating two-year life-history cycle, consistent with the intraspecific competition hypothesis for this phenomenon. At the small scale, we compared A. petiolata abundance with the abundance of other plants, including herbs, ferns, shrubs, and tree seedlings. We also conducted an ex-situ pot experiment in which we planted seeds of six tree species in soil collected from dense A. petiolata patches and soil collected where A. petiolata was absent and recorded emergence rates and seedling growth over an 8 wk period. Overall, we found little evidence that A. petiolata was negatively affecting other plant species. This is consistent with other recent studies and indicates that, despite earlier claims to the contrary, A. petiolata seems to be more a product than an agent of change in eastern North American deciduous forests. We also documented an alternating two-year life-history cycle, providing additional evidence to support the hypothesis that this cycle is at least partly being driven by intraspecific competition. [ABSTRACT FROM AUTHOR]