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1. Management actions shape dung beetle community structure and functional traits in restored tallgrass prairie

   https://doi.org/10.1111/een.12950  

   Hosler, Sheryl C. ; Jones, Holly P. ; Nelson, Melissa ; Barber, Nicholas A. ( September 2020 , Ecological Entomology)

   1. Ecosystem restoration often focuses on re‐establishing species richness and diversity of native organisms. However, effective restoration requires re‐establishment of ecosystem functions and processes by all trophic levels. Functional trait descriptions of communities, including decomposer communities, may provide more comprehensive evaluations of restoration activities and management than taxonomic community metrics alone.

   2. We examined species and functional trait composition of dung beetle (Coleoptera: Scarabaeidae, Geotrupidae) communities across a 3–31 yearchronosequence of restored prairies, in which sites varied in the presence of re‐introduced bison and prescribed fire. We calculated functional diversity metrics and community‐weighted mean trait values using behavioural and morphological measurements. We also performed a dung decomposition experiment to measure an ecosystem function driven by these insects.

   3. Bison presence doubled beetle abundance and increased richness by 50%. Shannon diversity increased with restoration age, nearly doubling from the youngest to oldest restorations. Functional diversity was unchanged by site characteristics, except functional richness, which was reduced by bison and fire presence. Beetles were, on average, smaller in older restorations, although this pattern was weaker when bison were present.

   4. Dung decomposition was unaffected by site characteristics but increased with community weighted mean beetle mass. Dung decomposition was better predicted by mean trait values, suggesting that supporting large‐bodied species may be more important than species diversity in settings where maximizing decomposition function is a goal.

   5. Restoration managers should consider dung beetle communities and their functional characteristics when making management decisions, particularly where large grazers are a component of management strategies.

    

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2. Reintroduced grazers and prescribed fire effects on beetle assemblage structure and function in restored grasslands

   https://doi.org/10.1002/eap.2217  

   Nelson, Melissa ; Hosler, Sheryl C. ; Boetzl, Fabian A. ; Jones, Holly P. ; Barber, Nicholas A. ( September 2020 , Ecological Applications)

   Ecological restoration seeks to reestablish functioning ecosystems, but planning and evaluation often focus on taxonomic community structure and neglect consumers and their functional roles. The functional trait composition of insect assemblages, which make up the majority of animal diversity in many systems, can reveal how they are affected by restoration management and the consequences for ecosystem function. We sampled ground beetle (Coleoptera: Carabidae) assemblages in restored tallgrass prairies varying in management with prescribed fire and reintroduced American bison (Bison bison) to describe their taxonomic and functional trait structure. We also measured seed and arthropod predation to relate management, beetle assemblage characteristics, and function, and to test if function is maximized by trait diversity, dominant trait values, or beetle abundance. Beetle assemblages primarily varied with restoration age, declining over time in richness and both taxonomic and functional diversity, but bison presence also influenced taxonomic composition. Prescribed fire reduced seed predation in summer and arthropod predation in fall. Although seed predation was unrelated to beetle assemblages, arthropod predation was greater in sites with higher abundances of carnivorous ground beetles. The relatively weak impacts of fire and bison on functional assemblage structure is a promising sign that these management disturbances, aimed at supporting a diverse native plant community, are not detrimental to beetle assemblages. The significance of reduced predator function following prescribed fire will depend on the restoration context and whether seed or arthropod predation relates to management goals.

    

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

   https://doi.org/10.1073/pnas.2015421118  

   Guiden, Peter W. ; Barber, Nicholas A. ; Blackburn, Ryan ; Farrell, Anna ; Fliginger, Jessica ; Hosler, Sheryl C. ; King, Richard B. ; Nelson, Melissa ; Rowland, Erin G. ; Savage, Kirstie ; et al ( February 2021 , Proceedings of the National Academy of Sciences)

   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. 

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4. Microbial Dispersal, Including Bison Dung Vectored Dispersal, Increases Soil Microbial Diversity in a Grassland Ecosystem

   https://doi.org/10.3389/fmicb.2022.825193  

   Hawkins, Jaide H. ; Zeglin, Lydia H. ( March 2022 , Frontiers in Microbiology)

   Microbial communities display biogeographical patterns that are driven by local environmental conditions and dispersal limitation, but the relative importance of underlying dispersal mechanisms and their consequences on community structure are not well described. High dispersal rates can cause soil microbial communities to become more homogenous across space and therefore it is important to identify factors that promote dispersal. This study experimentally manipulated microbial dispersal within different land management treatments at a native tallgrass prairie site, by changing the relative openness of soil to dispersal and by simulating vector dispersal via bison dung addition. We deployed experimental soil bags with mesh open or closed to dispersal, and placed bison dung over a subset of these bags, to areas with three different land managements: active bison grazing and annual fire, annual fire but no bison grazing, and no bison grazing with infrequent fire. We expected microbial dispersal to be highest in grazed and burned environments, and that the addition of dung would consistently increase overall microbial richness and lead to homogenization of communities over time. Results show that dispersal rates, as the accumulation of taxa over the course of the 3-month experiment, increase taxonomic richness similarly in all land management treatments. Additionally, bison dung seems to be serving as a dispersal and homogenization vector, based on the consistently higher taxon richness and increased community similarity across contrasting grazing and fire treatments when dung is added. This finding also points to microbial dispersal as an important function that herbivores perform in grassland ecosystems, and in turn, as a function that was lost at a continental scale following bison extermination across the Great Plains of North America in the nineteenth century. This study is the first to detect that dispersal and vector dispersal by grazing mammals promote grassland soil microbial diversity and affect microbial community composition. 

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5. Consumer roles of small mammals within fragmented native tallgrass prairie

   https://doi.org/10.1002/ecs2.3441  

   Hope, Andrew_G ; Gragg, Sabrina_F ; Nippert, Jesse_B ; Combe, Fraser_J ( March 2021 , Ecosphere)

   Grassland ecosystems globally are being negatively impacted by changes in climate, disturbance regimes, nutrient flux, and consumer guilds. Changes in the trophic ecology of consumers can substantially influence local resources, contributing to shifting diversity, community turnover, and other processes of ecosystem change. Small mammals are diverse and abundant within grasslands and yet the impact of changing ecosystems on small mammals and the role of these mammals as consumers are still both under‐studied. We assessed small mammal resource use within grassland and woodland vegetation types that have resulted from landscape‐scale experimental disturbance through fire treatments within the tallgrass prairie ecoregion of the North American Great Plains. We predicted that resource use would vary significantly among grassland vs. woodland communities, in turn reducing the role of small mammals in contributing to future maintenance of native prairies. We sampled five dominant species of rodents across three years and multiple habitats. Using stable isotope analysis, we investigated isotopic niche area and overlap to infer variation in diet, both within and among species. Resource use shifted in bivariate isotopic space seasonally but not across years when combining all species and habitats. Inferred spring diet (based on fur samples) was highly diverse and overlapping. Summer isotopic values (based on liver tissue) in woody habitat treatments were narrower and overlapped less than within grassland habitats. Consumers generally shifted from C₄herbivory to C₃herbivory, or greater omnivory, when analyzing grassland, shrubland, and woodland habitats respectively. Within the tallgrass prairie ecosystem, small mammal populations in herbaceous‐dominated habitats use a broader variety of resources than small mammals in proximate woody‐dominated habitats. As native grasslands experience woody encroachment, small mammal assemblages experience turnover of dominant species and associated changes in diet. Ecosystem changes such as cessation of frequent fire resulting in more woody habitats may include reduced roles by native small mammals as consumers/dispersers/propagators of native grassland plants.

    

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