An official website of the United States government
Abstract Restoring ecosystems requires the re-establishment of diverse soil microbial communities that drive critical ecosystem functions. In grasslands, restoration and management require the application of disturbances like fire and grazing. Disturbances can shape microbial taxonomic composition and potentially functional composition as well. We characterized taxonomic and functional gene composition of soil communities using whole genome shotgun metagenomic sequencing to determine how restored soil communities differed from pre-restoration agricultural soils and original remnant soils, how management affects soil microbes, and whether restoration and management affect the number of microbial genes associated with carbohydrate degradation. We found distinct differences in both taxonomic and functional diversity and composition among restored, remnant, and agricultural soils. Remnant soils had low taxonomic and functional richness and diversity, as well as distinct composition, indicating that restoration of agricultural soils does not re-create soil microbial communities that match remnants. Prescribed fire management increased functional diversity, which also was higher in more recently planted restorations. Finally, restored and post-fire soils included high abundances of genes encoding cellulose-degrading enzymes, so restorations and their ongoing management can potentially support functions important in carbon cycling.
more »
« less
Restoration age and reintroduced bison may shape soil bacterial communities in restored tallgrass prairies
Abstract Knowledge of how habitat restoration shapes soil microbial communities often is limited despite their critical roles in ecosystem function. Soil community diversity and composition change after restoration, but the trajectory of these successional changes may be influenced by disturbances imposed for habitat management. We studied soil bacterial communities in a restored tallgrass prairie chronosequence for >6 years to document how diversity and composition changed with age, management through fire, and grazing by reintroduced bison, and in comparison to pre-restoration agricultural fields and remnant prairies. Soil C:N increased with restoration age and bison, and soil pH first increased and then declined with age, although bison weakened this pattern. Bacterial richness and diversity followed a similar hump-shaped pattern as soil pH, such that the oldest restorations approached the low diversity of remnant prairies. β-diversity patterns indicated that composition in older restorations with bison resembled bison-free sites, but over time they became more distinct. In contrast, younger restorations with bison maintained unique compositions throughout the study, suggesting bison disturbances may cause a different successional trajectory. We used a novel random forest approach to identify taxa that indicate these differences, finding that they were frequently associated with bacteria that respond to grazing in other grasslands.
more »
« less
- PAR ID:
- 10401670
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- FEMS Microbiology Ecology
- Volume:
- 99
- Issue:
- 3
- ISSN:
- 1574-6941
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
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.more » « less
-
Disturbances are drivers of ecosystem function and play important roles in shaping ecological communities. Pre- scribed fire and grazing disturbances are common management tools in restored and remnant grasslands. The effects of these management actions on plant communities and on vegetation-dwelling invertebrates are generally well studied. However, less is known about their effects on ground-dwelling invertebrates, which can contribute to important ecosystem processes like herbivory, predation, and decomposition. We examined bison grazing and prescribed fire effects on abundance, diversity, and community composition of ground-dwelling invertebrate groups in restored tallgrass prairies using pitfall trap samples. Surprisingly, invertebrate Shannon diversity decreased when bison were present and was unaffected by fire or the fire–bison interaction. Bison, and to a lesser extent fire, also shifted community composition, increasing abundance of ground, rove, and dung beetles, as well as orthopterans and spiders. Prescribed fire generally increased beetles but caused declines in sev- eral ecologically diverse invertebrate groups, including harvestmen and true bugs, although these reduced abundances did not lead to differences in overall diversity. Bison presence may amplify the abundances of dominant groups, such as ground and dung beetles and orthopterans, that outcompete other invertebrates and reduce diversity. Implications for insect conservation Prescribed fire and grazing by bison change ground-dwelling invertebrate community composition, but bison presence did not reduce the abundance of most taxonomic groups. Fire may have short-term negative impacts on some invertebrate groups that promote desirable invertebrate-driven ecosystem processes, but these effects are likely short-lived, and the resulting environmental mosaic under bison and fire management could support biodiversity over the long-term.more » « less
-
Blubaugh, Carmen (Ed.)Abstract Ecosystem restoration is a critical component of land management, countering the loss of native biodiversity. Restoration efforts are enhanced by reintroducing naturally occurring ecosystem processes, including disturbances that may impact species characteristics such as niche position or niche size. In grasslands, grazing and fire affect plant diversity and habitat complexity, which potentially influence insect dietary behaviors and thus their contributions to functions like seed and arthropod predation. Using carbon and nitrogen stable isotopes, we characterized variation in the dietary niche of six ground beetle species (Coleoptera: Carabidae) in response to grazing by reintroduced bison and prescribed fire disturbances in twenty tallgrass prairies. Management disturbances did not affect activity density for most beetle species and mean trophic position was mostly unaffected. However, five of six species exhibited increased trophic niche area and breadth with disturbances, indicating a switch to a more generalist diet that incorporated a wider range of food items. The combination of bison and fire impacts may increase vegetation patchiness and heterogeneity, driving these diet changes. Morphological traits and microhabitat preferences might mediate response to disturbances and the resulting heterogeneity. Combining prescribed fire and grazing, which increases plant diversity and vegetation structural diversity, may help beetle communities establish over time and support the ecological functions to which these insects contribute.more » « less
-
Abstract 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.more » « less
