Evaluating the prevalence and quality of conference codes of conduct.

Efforts to increase inclusion in science face multiple barriers, including cultural and social behaviors in settings such as academic conferences. Conferences are beneficial, but the culture can promote inequities and power differentials that harm historically underrepresented groups. Science suffers when conference culture propagates exclusion and discrimination that leads to attrition of scientists. Codes of conduct represent a tool to shift conference culture to better support diverse scientists and clearly detail unacceptable behaviors. We examined the prevalence and content of codes of conduct at biology conferences in the United States and Canada. We highlight how codes of conduct address issues of sexual misconduct and identity-based discrimination. Surprisingly, only 24% of the 195 surveyed conferences had codes. Of the conferences with codes, 43% did not mention sexual misconduct and 17% did not mention identity-based discrimination. Further, 26% of these conferences failed to include a way to report violations of the code and 35% lacked consequences for misconduct. We found that larger and national conferences are more likely to have codes than smaller (P = 0.04) and international or regional (P = 0.03) conferences. Conferences that lack codes risk creating and perpetuating negative environments that make underrepresented groups feel unwelcome, or worse, actively cause harm. We recommend that conferences have codes that are easily accessible, explicitly address identity-based discrimination and sexual misconduct, provide channels for anonymous impartial reporting, and contain clear consequences. These efforts will improve inclusivity and reduce the loss of scientists who have been historically marginalized.

Evolutionary history shapes grassland productivity through opposing effects on complementarity and selection.

Phylogenetic diversity (PD), the evolutionary history of the organisms comprising a community, is increasingly recognized as an important driver of ecosystem function. However, biodiversity-ecosystem function experiments have rarely included PD as an a priori treatment. Thus, PD's effects in existing experiments are often confounded by covarying differences in species richness and functional trait diversity (FD). Here we report an experimental demonstration of strong PD effects on grassland primary productivity that are independent of FD, which was separately manipulated, and species richness, which was planted uniformly high to mimic diverse natural grasslands. Partitioning diversity effects demonstrated that higher PD increased complementarity (niche partitioning and/or facilitation) but lowered selection effects (probability of sampling highly productive species). Specifically, for every 5% increase in PD, complementarity increased by 26% on average (±8% SE), while selection effects decreased more modestly (8 ± 16%). PD also shaped productivity through clade-level effects on functional traits, that is, trait values associated with particular plant families. This clade effect was most pronounced in the Asteraceae (sunflower family), which, in tallgrass prairies, generally comprises tall, high-biomass species with low phylogenetic distinctiveness. FD also reduced selection effects but did not alter complementarity. Our results show that PD, independent of richness and FD, mediates ecosystem function through contrasting effects on complementarity and selection. This adds to growing evidence that consideration of phylogenetic dimensions of biodiversity can advance ecological understanding and inform conservation and restoration.

Cracking the case: Seed traits and phylogeny predict time to germination in prairie restoration species.

Traits are important for understanding how plant communities assemble and function, providing a common currency for studying ecological processes across species, locations, and habitat types. However, the majority of studies relating species traits to community assembly rely upon vegetative traits of mature plants. Seed traits, which are understudied relative to whole-plant traits, are key to understanding assembly of plant communities. This is particularly true for restored communities, which are typically started de novo from seed, making seed germination a critical first step in community assembly and an early filter for plant establishment. We experimentally tested the effects of seed traits (mass, shape, and embryo to seed size ratio) and phylogeny on germination response in 32 species commonly used in prairie grassland restoration in the Midwestern USA, analyzing data using time-to-event (survival) analysis. As germination is also influenced by seed dormancy, and dormancy break treatments are commonly employed in restoration, we also tested the effects of two pretreatments (cold stratification and gibberellic acid application) on time to germination. Seed traits, phylogeny, and seed pretreatments all affected time to germination. Of all traits tested, variables related to seed shape (height and shape variance) best predicted germination response, with high-variance (i.e., pointier and narrower) seeds germinating faster. Phylogenetic position (the location of species on the phylogenetic tree relative to other tested species) was also an important predictor of germination response, that is, closely related species showed similar patterns in time to germination. This was true despite the fact that all measured seed traits showed phylogenetic signal, therefore phylogeny provided residual information that was not already captured by measured seed traits. Seed traits, phylogenetic position, and germination pretreatments were important predictors of germination response for a suite of species commonly used in grassland restoration. Shape traits were especially important, while mass, often the only seed trait used in studies of community assembly, was not a strong predictor of germination timing. These findings illustrate the ecological importance of seed traits that are rarely incorporated into functional studies of plant communities. This information can also be used to advance restoration practice by guiding restoration planning and seed mix design.