Draft Genome Sequences of Switchgrass Diazotrophs

We report the draft genome sequences of five native nitrogen-fixing bacteria associated with roots of switchgrass isolated from the Tallgrass Prairies of Oklahoma. Nitrogen-fixing genes, including the nif cluster, are conserved across the Klebsiella and Kosakonia strains.

Effects of management outweigh effects of plant diversity on restored animal communities in tallgrass prairies

A primary goal of ecological restoration is to increase biodiversity in degraded ecosystems. However, the success of restoration ecology is often assessed by measuring the response of a single functional group or trophic level to restoration, without considering how restoration affects multitrophic interactions that shape biodiversity. An ecosystem-wide approach to restoration is therefore necessary to understand whether animal responses to restoration, such as changes in biodiversity, are facilitated by changes in plant communities (plant-driven effects) or disturbance and succession resulting from restoration activities (management-driven effects). Furthermore, most restoration ecology studies focus on how restoration alters taxonomic diversity, while less attention is paid to the response of functional and phylogenetic diversity in restored ecosystems. Here, we compared the strength of plant-driven and management-driven effects of restoration on four animal communities (ground beetles, dung beetles, snakes, and small mammals) in a chronosequence of restored tallgrass prairie, where sites varied in management history (prescribed fire and bison reintroduction). Our analyses indicate that management-driven effects on animal communities were six-times stronger than effects mediated through changes in plant biodiversity. Additionally, we demonstrate that restoration can simultaneously have positive and negative effects on biodiversity through different pathways, which may help reconcile variation in restoration outcomes. Furthermore, animal taxonomic and phylogenetic diversity responded differently to restoration, suggesting that restoration plans might benefit from considering multiple dimensions of animal biodiversity. We conclude that metrics of plant diversity alone may not be adequate to assess the success of restoration in reassembling functional ecosystems.

Bison, anthropogenic fire, and the origins of agriculture in eastern North America

Scholars have argued that plant domestication in eastern North America involved human interactions with floodplain weeds in woodlands that had few other early successional environments. Archeological evidence for plant domestication in this region occurs along the Mississippi river and major tributaries such as the Tennessee, Ohio, Illinois, Missouri, and Arkansas rivers. But this region is also known as the prairie peninsula: a prairie-woodland mosaic that was maintained by anthropogenic fire starting as early as 6000 BP. Contrary to conventional wisdom, recent research has shown that bison were also present in the prairie peninsula throughout the Holocene. Recent reintroductions of bison to tallgrass prairies have allowed ecologists to study the effects of their grazing on this ecosystem for the first time. Like rivers and humans, bison create early successional habitats for annual forbs and grasses, including the progenitors of eastern North American crops, within tallgrass prairies. Our fieldwork has shown that crop progenitors are conspicuous members of plant communities along bison trails and in wallows. We argue that ancient foragers encountered dense, easily harvestable stands of crop progenitors as they moved along bison trails, and that the ecosystems created by bison and anthropogenic fire served as a template for the later agroecosystem of this region. Without denying the importance of human-river interactions highlighted by previous researchers, we suggest that prairies have been ignored as possible loci for domestication, largely because the disturbed, biodiverse tallgrass prairies created by bison have only been recreated in the past three decades after a century of extinction.