Phylogenetic and functional diversity are relevant for restoration planning, as they influence important ecosystem functions and services. However, it is unknown whether initial phylogenetic and functional diversity of restorations as planned and planted are maintained over time, that is, the extent to which diversity of the restoration planting is reflected in the diversity of the resulting plant community. Furthermore, in the tallgrass prairie, many restorations are planted from seed. Among‐species variation in emergence and establishment affects the transition from seed mixes to realized plant communities in these restorations. We evaluated emergence and early establishment of experimental communities in a biodiversity plot experiment designed to test how phylogenetic and functional diversity influence restoration outcomes. We planted the same experimental communities starting from both seeds and plugs to assess differences in establishment. Our results suggest that phylogenetically and functionally diverse species mixes tend to produce phylogenetically and functionally diverse restored plant communities. After 3 years, experimental communities generally maintained their phylogenetic and functional diversity from seed and plug mixes to established vegetation, despite declines in species richness. While plots planted from seeds had on average 1.3 fewer species than plots planted from plugs, phylogenetic and functional diversity did not significantly differ between the two. Furthermore, most species exhibited no significant differences in percent cover when planted from seeds or plugs. Seeds are generally more cost‐effective for restoration than plugs, and our results indicate these two establishment methods achieved similar biodiversity outcomes.
Recovering biodiversity is a common goal of restoration, yet outcomes for animal communities are highly variable. A major reason for this variability may be that active restoration efforts typically target plant communities, with the assumption that animal communities will passively recover in turn. However, this assumption remains largely unvalidated experimentally making it unclear how plant‐focused restoration strategies influence animal communities. We evaluated how the diversity of seed mixes used to restore tallgrass prairies (a common plant‐focused technique) influenced the recovery of ant community diversity and composition. Our study took place within a large‐scale restoration experiment in southwest Michigan, where 12 former agricultural fields are being restored to tallgrass prairie by sowing seeds of prairie plant species native to our region. Half of each field was seeded with 12 prairie species and the other half with 72 prairie species. Sites restored with high diversity seed mixes increased plant species richness, but did not consistently influence ant richness or community composition. Instead, ant species richness and composition were related to an interaction between realized plant species richness (which was only partly structured by seeding treatments) and environmental structure. Specifically, ant richness increased more with higher realized plant richness when vegetation cover was lower and soil‐surface temperatures were higher. Our findings illustrate how plant and animal communities can respond differently to plant‐focused restoration efforts. Despite this, plant community restoration can structure animal community responses, in concert with environmental factors. Layering additional restoration strategies onto existing plant‐focused approaches may further benefit biodiversity across taxa.more » « less
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- Restoration Ecology
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- National Science Foundation
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Phylogenetic and species‐based taxonomic descriptions of community structure may provide complementary information about the mechanisms driving community assembly across different environments. Environmental filtering may have similar effects on taxonomic and phylogenetic diversity under the assumption of niche conservatism, whereas competitive exclusion could produce contrasting patterns in these diversity metrics. In grassland restorations, these diversity patterns might then reveal potential assembly mechanisms underlying the impacts of restoration and management conditions on community structure.
We compared plant community structure (alpha diversity, composition, and within‐site beta diversity) from both phylogenetic and taxonomic perspectives. Using surveys from 120 tallgrass prairie restorations in four regions of the Midwestern United States, we examined the effects of four potential drivers or environmental gradients: precipitation in the first year of restoration, seed mix richness, time since last prescribed fire, and restoration age, and included soil conditions as a covariate.
First‐year precipitation influenced taxonomic community structure, but had weak effects on phylogenetic diversity and composition. Similarly, greater seed mix richness increased taxonomic diversity but did not influence phylogenetic diversity. Taxonomic, but not phylogenetic, diversity generally was lower in older restorations and those with a longer time since the last prescribed fire. These drivers consistently explained more variation in taxonomic than phylogenetic diversity and composition, perhaps in part because species turnover was largely among related species, producing weak impacts on phylogenetic community measures.
An impact of precipitation on taxonomic but not phylogenetic diversity suggests that there may not be large differences in drought tolerance among clades that would cause phylogenetic patterns to arise from this environmental filter. Declining taxonomic diversity but not phylogenetic diversity is consistent with competitive exclusion as an assembly mechanism when competition is strongest between related species.
Synthesis. This research shows how studying taxonomic and phylogenetic diversity of ecosystem restorations can inform plant community ecology and help natural resource managers better predict the outcomes of restoration actions and management.
Restoration in this era of climate change comes with a new challenge: anticipating how best to restore populations to persist under future climate conditions. Specifically, it remains unknown whether locally adapted or warm‐adapted seeds best promote native plant community restoration in the warmer conditions predicted in the future and whether local or warm‐adapted soil microbial communities could mitigate plant responses to warming. This may be especially relevant for biomes spanning large climatic gradients, such as the North American tallgrass prairie. Here, we used a short‐term mesocosm experiment to evaluate how seed provenances (Local Northern region, Non‐local Northern region, Non‐local Southern region) of 10 native tallgrass prairie plants (four forbs, two legumes, and four grasses) responded to warmer conditions predicted in the future and how soil microbial communities from those three regions influenced these responses. Warming and seed provenance affected plant community composition and warming decreased plant diversity for all three seed provenances. Plant species varied in their individual responses to warming, and across species, we detected no consistent differences among the three provenances in terms of biomass response to warming and few strong effects of soil provenance. Our work provides evidence that warming, in part, may reduce plant diversity and affect restored prairie composition. Because the southern provenance did not consistently outperform others under warming and we found little support for the “local is best” paradigm currently dominating restoration practice, identifying appropriate seed provenances to promote restoration success both now and in future warmer environments may be challenging. Due to the idiosyncratic responses across species, we recommend that land managers compare seeds from different regions for each species to determine which seed provenance performs best under warming and in restoration for 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.more » « less
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.