Landscape-scale differences among cities alter common species' responses to urbanization.

Understanding how biodiversity responds to urbanization is challenging, due in part to the single-city focus of most urban ecological research. Here, we delineate continent-scale patterns in urban species assemblages by leveraging data from a multi-city camera trap survey and quantify how differences in greenspace availability and average housing density among 10 North American cities relate to the distribution of eight widespread North American mammals. To do so, we deployed camera traps at 569 sites across these ten cities between 18 June and 14 August. Most data came from 2017, though some cities contributed 2016 or 2018 data if it was available. We found that the magnitude and direction of most species' responses to urbanization within a city were associated with landscape-scale differences among cities. For example, eastern gray squirrel (Sciurus carolinensis), fox squirrel (Sciurus niger), and red fox (Vulpes vulpes) responses to urbanization changed from negative to positive once the proportion of green space within a city was >~20%. Likewise, raccoon (Procyon lotor) and Virginia opossum (Didelphis virginiana) responses to urbanization changed from positive to negative once the average housing density of a city exceeded about 700 housing units/km2 . We also found that local species richness within cities consistently declined with urbanization in only the more densely developed cities (>~700 housing units/km2 ). Given our results, it may therefore be possible to design cities to better support biodiversity and reduce the negative influence of urbanization on wildlife by, for example, increasing the amount of green space within a city. Additionally, it may be most important for densely populated cities to find innovative solutions to bolster wildlife resilience because they were the most likely to observe diversity losses of common urban species.

A modern method of multiple working hypotheses to improve inference in ecology.

Science provides a method to learn about the relationships between observed patterns and the processes that generate them. However, inference can be confounded when an observed pattern cannot be clearly and wholly attributed to a hypothesized process. Over-reliance on traditional single-hypothesis methods (i.e. null hypothesis significance testing) has resulted in replication crises in several disciplines, and ecology exhibits features common to these fields (e.g. low-power study designs, questionable research practices, etc.). Considering multiple working hypotheses in combination with pre-data collection modelling can be an effective means to mitigate many of these problems. We present a framework for explicitly modelling systems in which relevant processes are commonly omitted, overlooked or not considered and provide a formal workflow for a pre-data collection analysis of multiple candidate hypotheses. We advocate for and suggest ways that pre-data collection modelling can be combined with consideration of multiple working hypotheses to improve the efficiency and accuracy of research in ecology.

Investigating Undergraduate Biology Students' Science Identity Production.

Identity production is a complex process in which a person determines who he or she is via internal dialogue and sociocultural participation. Understanding identity production is important in biology education, because students' identities impact classroom experiences and their willingness to persist in the discipline. Thus, we suggest that educators foster spaces where students can engage in producing science identities that incorporate positive perceptions of who they are and what they have experienced. We used Holland's theory of identity and Urrieta's definitions of conceptual identity production (CIP) and procedural identity production (PIP) to explore the process of students' science identity production. We interviewed 26 students from five sections of a general biology course for majors at one higher education institution. The interview protocol included items about students' identities, influential experiences, perceptions of science, and perceptions of their classroom communities. From the interviews, we developed hierarchical coding schemes that focused on characterizing students' CIP and PIP. Here, we describe how students' socially constructed identities (race, gender, etc.) and their experiences may have impacted the production of their science identities. We found that authoring (i.e., making meaning of) experiences and recognition by others as a community member influenced students' science identity production.

Principles and Strategies for Effective Teaching: A Workshop for Pre- and Postdoctoral Trainees in the Biomedical Sciences.

The 2012 National Institutes of Health (NIH) Biomedical Workforce Working Group Report documented that graduate training in the biomedical sciences predominantly prepares people for academic research positions. The report recommended that NIH provide funds for institutions to develop broader career development opportunities, including training related to teaching. Indeed, teaching is not only a required component of any faculty position, it is the primary task for trainees who seek employment at small liberal arts colleges and other primarily undergraduate institutions. NIH funding for the BEST (Broadening Experiences in Scientific Training) programs allowed us to develop a six-week training workshop for bioscience trainees to introduce participants to research-based, student-centered pedagogies and instructional design techniques and to inspire them to view teaching as an intellectual endeavor. The methods and outcomes of our case study should be applicable in a variety of programs and organizations, especially those with a separate health science campus, where faculty mentors often do not teach many classes and there are few, if any, apprenticeship-teaching opportunities for trainees.

Crossing the Threshold: Bringing Biological Variation to the Foreground.

Threshold concepts have been referred to as "jewels in the curriculum": concepts that are key to competency in a discipline but not taught explicitly. In biology, researchers have proposed the idea of threshold concepts that include such topics as variation, randomness, uncertainty, and scale. In this essay, we explore how the notion of threshold concepts can be used alongside other frameworks meant to guide instructional and curricular decisions, and we examine the proposed threshold concept of variation and how it might influence students' understanding of core concepts in biology focused on genetics and evolution. Using dimensions of scientific inquiry, we outline a schema that may allow students to experience and apply the idea of variation in such a way that it transforms their future understanding and learning of genetics and evolution. We encourage others to consider the idea of threshold concepts alongside the Vision and Change core concepts to provide a lens for targeted instruction and as an integrative bridge between concepts and competencies.

The effects of black-tailed prairie dogs on plant communities within a complex urban landscape: an ecological surprise?

Historically, prairie dogs (Cynomys spp.) have been considered essential keystone species of western United States grassland ecosystems because they provide unique services and increase vegetation community richness, evenness, and diversity. However, the effects of black-tailed prairie dogs (Cynomys ludovicianus) on lands adjacent to or surrounded by urban areas may not result in the same ecosystem benefits historically associated with their presence. An urban landscape presents prairie dogs with movement challenges unparalleled in natural landscapes, as well as suites of nonnative plant species that are more common in disturbed areas. This study examined a complex ecosystem where vegetation communities are being influenced by directional environmental change, and quantified the synergistic effects resulting from the protective management of a native keystone species. The data set for this analysis was comprised of 71 paired (occupied by prairie dogs vs. unoccupied) vegetation surveys and 156 additional unpaired surveys collected from around the city of Boulder, Colorado, USA for 14 yr. Linear mixed models were used to compare data from transects occupied and unoccupied by prairie dogs, as well as to evaluate the effect of prairie dog occupation duration. In the absence of prairie dogs, vegetation in this region exhibited declines in native grasses, no changes in introduced grasses, and increases in native and nonnative forbs and bare soil over the study interval. In the presence of prairie dogs, these observed directional changes were nearly all amplified at rates four to 10 times greater than when prairie dogs were absent. Areas in Boulder occupied by prairie dogs also had significantly lower richness, evenness, and diversity of plant species, compared to unoccupied areas. Analysis of plant functional groups revealed the significant reduction of perennial native grasses, as well as a significantly higher cover of introduced forbs in occupied areas. Prairie dogs amplified the effects of low-impact environmental directional changes, creating more novel vegetation communities than the environmental factors alone. Results from this research provide insight regarding the synergistic effects of a native keystone species within a complex human-impacted 21st century landscape.