Prairie Remnants Research Articles

Soil microbial community composition in tallgrass prairie restorations converge with remnants across a 27-year chronosequence.

Restoration and management of natural ecosystems is a critical strategy in mitigating global biodiversity loss. This is exemplified in the American Midwest by efforts aimed at reclaiming historical grasslands lost to high-yield agriculture. While restorations traditionally take the form of plant reintroduction and management, advances in microbial analyses suggest that soil communities could be indicators restoration success. However, current understanding of key microbial taxa and functional activities in both natural and restored ecosystems is limited. Here, we investigated the impact of nearly 30 years of carefully managed restoration on soil microbial communities at the Nachusa Grasslands in northern Illinois, USA. We characterized bacterial and archaeal communities in a chronosequence of restored tallgrass prairies ranging from 1 to 27 years old across a growing season and compared them to communities in pre-restoration agricultural fields and remnant prairies. Results indicate that older restorations harboured communities statistically distinct from newer restorations. These communities converged toward those in local prairie remnants, suggesting that plant-focussed restoration has yielded soil bacterial communities reflective of a successful restoration. Recovery of microbial clades within the Verrucomicrobia and Acidobacteria are an important feature of this convergence, and these groups could be targeted for future soil-focussed, bottom-up restoration studies.

Effects of Patchburn Grazing on Vegetative Composition of Tallgrass Prairie Remnants in Missouri

ABSTRACT: Patch-burn grazing is a grassland management approach that recouples the processes of fire and grazing altering animal distribution and creating structural heterogeneity for the benefit of flora and fauna biodiversity. Our objective was to investigate the effects of patch-burn grazing on plant species composition in tallgrass prairie remnants on conservation lands in Missouri. Each grazed unit consisted of three patches with each patch approximately one-third the size of the grazed unit. We burned a different patch annually and stocked the entire unit at a moderate rate of 0.45 AUM/ha with yearling stocker steers. We established paired plots of treatment (grazed) and control (grazing excluded) and sampled vegetative composition during a 3-yr graze-burn cycle and a fourth year of no treatments. Species richness, diversity, and floristic quality of exclosures were compared between plots using the Shannon, Simpson, and Floristic Quality indices. Our results indicated a year × treatment interaction....

Agroecological and environmental factors influence Barley yellow dwarf viruses in grasslands in the US Pacific Northwest

Plant pathogens can play a role in the competitive interactions between plant species and have been understudied in native prairies, which are declining globally, and in Conservation Reserve Program (CRP) lands in the United States. Barley/Cereal yellow dwarf virus (B/CYDV) are among the most economically important disease-causing agents of small grain cereal crops, such as wheat, and are known to infect over 150 Poaceae species, including many of the grass species present in prairies and CRP lands. Field surveys of Poaceae species were conducted in endangered Palouse Prairie and CRP habitats of southeastern Washington and adjacent northern Idaho, USA from 2010 to 2012 to examine for the presence of B/CYDV among plant hosts and aphid vectors. Viral species were identified via cloning and sequencing. Landscape, soil and climate data were retrieved from USDA-NASS and USDA-NRCS databases. Analyses were conducted to examine effects of diverse agroecological and environmental factors on virus prevalence. A total of 2271 grass samples representing 30 species were collected; 28 of these were infected with BYDV in at least one location. BYDV infection was detected at every CRP and prairie remnant sampled, with an overall infection of 46%. BYDV-SGV and BYDV-PAV were the only two B/CYDV species encountered, with BYDV-SGV being more prevalent. Sampling time (season) and host plant identity were the main variables explaining variation in virus prevalence among sites. BYDV was more prevalent in perennial compared to annual grass species. Aphids were encountered only once suggesting non-colonizing aphids, potentially from neighboring cereal fields, are responsible for disease spread in these habitats. BYDV prevalence increased in sampled habitats as cereal crop cover increased within a 1-km radius of a habitat patch. Results demonstrate moderate to high and persistent prevalence of BYDV in an endangered grassland habitat. Species composition and susceptibility to pathogens should be considered when creating seed mixes for CRP sites, especially in relation to agricultural crops and diseases in a region. Future work exploring host abundance, competence and habitat utilization by vectors is required to fully elucidate BYDV ecology and epidemiology in grassland habitats.

Targeting Introduced Species to Improve Plant Community Composition on USFWS-Managed Prairie Remnants

The quality of plant community composition on US Fish and Wildlife Service (USFWS) lands in North Dakota and South Dakota has declined over the past several decades—the abundance of native species has decreased while the abundance of introduced species has rapidly increased. Extensive efforts have been made to improve plant community composition on USFWS prairies; however, there was not a unified approach to this end in North Dakota and South Dakota until the advent of the Native Prairie Adaptive Management (NPAM) program. The NPAM program provides decision support for the selection of management actions to improve plant community composition of tallgrass and mixed-grass prairies in the Northern Great Plains. We evaluated plant community composition on USFWS native tallgrass and mixed-grass prairie remnants enrolled in the NPAM program in North Dakota and South Dakota to examine effects of management on plant community composition. Our analysis suggests that incorporating certain management actions can improve plant community characteristics on the agency's tallgrass and mixed-grass prairies. We documented increased native species richness and decreased Bromus inermis (smooth brome) relative cover at sites that had been burned two or more times during a four-year period. In contrast, smooth brome relative cover was higher at sites managed by the exclusion of fire and intermittent light grazing or rest. Smooth brome is extremely invasive in native prairie remnants throughout the Northern Great Plains. Thus, our results have marked implications for managers working to reduce the prevalence of smooth brome on public and private lands.

Bee communities along a prairie restoration chronosequence: similar abundance and diversity, distinct composition.

Recognition of the importance of bee conservation has grown in response to declines of managed honey bees and some wild bee species. Habitat loss has been implicated as a leading cause of declines, suggesting that ecological restoration is likely to play an increasing role in bee conservation efforts. In the midwestern United States, restoration of tallgrass prairie has traditionally targeted plant community objectives without explicit consideration for bees. However, restoration of prairie vegetation is likely to provide ancillary benefits to bees through increased foraging and nesting resources. We investigated community assembly of bees across a chronosequence of restored eastern tallgrass prairies and compared patterns to those in control and reference habitats (old fields and prairie remnants, respectively). We collected bees for 3yr and measured diversity and abundance of in-bloom flowering plants, vegetation structure, ground cover, and surrounding land use as predictors of bee abundance and bee taxonomic and functional diversity. We found that site-level variables, but not site type or restoration age, were significant predictors of bee abundance (bloom diversity, P=0.004; bare ground cover, P=0.02) and bee diversity (bloom diversity, P=0.01). There were significant correlations between overall composition of bee and blooming plant communities (Mantel test, P=0.002), and both plant and bee assemblages in restorations were intermediate between those of old fields and remnant prairies. Restorations exhibited high bee beta diversity, i.e., restored sites' bee assemblages were taxonomically and functionally differentiated from each other. This pattern was strong in younger restorations (<20yr old), but absent from older restorations (>20yr), suggesting restored prairie bee communities become more similar to one another and more similar to remnant prairie bee communities over time with the arrival of more species and functional groups of bees. Our results indicate that old fields, restorations, and remnants provide habitat for diverse and abundant bee communities, but continued restoration of old fields will help support and conserve bee communities more similar to reference bee communities characteristic of remnant prairies.

Restored tallgrass prairies have reduced phylogenetic diversity compared with remnants

SummaryEcological restoration is critical for mitigating habitat loss and providing ecosystem services. However, restorations often have lower diversity than remnant, reference sites. Phylogenetic diversity is an important component of biodiversity and ecosystem function that has only recently been used to evaluate restoration outcomes. To move towards prediction in the restoration of biodiversity, it is necessary to understand how phylogenetic diversity of restorations compares with that of reference sites, and where deficits are found, to evaluate factors constraining phylogenetic diversity.We quantified plant taxonomic and phylogenetic diversity in eastern tallgrass prairie, one of the most endangered ecosystems on earth. We measured diversity at large (site) and small (plot) scales in 19 restored prairies and compared patterns with those from 41 remnant prairies. To evaluate how environmental conditions and management actions influence outcomes, we tested the effects of soil properties and seed mix composition on diversity of restorations.Restored prairies were less phylogenetically diverse than remnants at both spatial scales. On the other hand, the total species richness of remnant and restored prairies did not significantly differ, but remnants had higher native richness. Restored communities were taxonomically and phylogenetically distinct from remnants.Soil properties (moisture andpH) influenced phylogenetic diversity and composition. There were positive relationships between the taxonomic and phylogenetic diversity of seed mixes and resulting diversity of planted assemblages (excluding volunteer species). Species in seed mixes were more closely related than expected by chance, and several clades found in remnant prairies were missing from seed mixes.Synthesis and applications. Restored tallgrass prairies had lower phylogenetic diversity than remnant prairies, which may contribute to the widely observed phenomenon of restorations not being functionally equivalent to reference sites. It is encouraging for restoration efforts that seed mix phylogenetic diversity predicted phylogenetic diversity of planted assemblages. This indicates that designing phylogenetically diverse seed mixes for restoration is beneficial. In addition, clades found in reference sites that are missing from restoration seed mixes could be added to new or existing restorations to reduce gaps in phylogenetic diversity. Further work on the effects of management on phylogenetic diversity is needed to advance restoration of biodiversity.

Grassland songbird occurrence on remnant prairie patches is primarily determined by landscape characteristics

North American grassland songbird populations have declined significantly due to habitat loss and fragmentation. Understanding the influence of the surrounding landscape on prairie fragment occupancy is vital for predicting the fate of grassland birds in these heavily altered landscapes. We examined the relative importance of local and landscape variables on grassland bird occupancy of prairie fragments using a focal-patch study. We also investigated the spatial scale at which landscape variables were most influential. We surveyed birds on 29 unplowed prairie fragments in western Minnesota and eastern North and South Dakota. We quantified local habitat on the fragment using vegetation surveys and aerial photographs and the landscape surrounding the fragment out to 4 km using aerial photographs. We analyzed occupancy using multi-model approaches applied to multiple logistic regression. Of 38 species encountered, nine were neither too rare nor too abundant to be analyzed. Predictors of patch occupancy were unique for each bird species, yet general patterns emerged. For eight species, landscape variables were more important than local variables. Mostly, those landscape variables measured configuration (e.g., edge density) and not composition (e.g., percent cover of a particular matrix element). Landscape effects were mostly from variables measured at the greatest extents from the prairie fragment. Using a focal-patch study design we demonstrated the importance of the surrounding landscape, often out to 4 km from the fragment edge, on prairie occupancy by grassland birds. Effective management of grassland songbirds will require attention to the landscape context of prairie fragments.

Research Article: Relationships between plant community species richness, remnant area, and invasive leafy spurge cover in southeastern Minnesota bluff prairie habitats

Abstract Bluff prairies are extreme habitats centered on southwestern facing bluffs along major rivers in the driftless area of the upper Midwest. Characterized by steep slopes, thin soils, and intense exposure to sun and wind, bluff prairies harbor a much warmer, drier microclimate than is found elsewhere in the region. Such harsh conditions help preserve bluff prairie habitat for unique communities of plants and animals. However, like many prairie habitats, bluff prairies are shrinking in size and experiencing fragmentation, resulting in smaller prairie remnants rather than larger, intact prairies. This shrinking and fragmentation is likely a consequence of non-prairie and/or non-native plants encroaching from the edges. One prominent introduced invasive species, leafy spurge (Euphorbia esula), has the ability to spread quickly and displace native plants. During the summer of 2012, the native flowering plant communities (excluding grasses, rushes, and sedges), prairie remnant sizes, and invasive leafy s...

Platte Prairies Ants (Hymenoptera: Formicidae) in Restored and Remnant Prairie Tracts in Central Nebraska

ABSTRACT In July 2012, we sampled ant species in remnant and restored prairie tracts in the Platte River Prairies, managed by The Nature Conservancy of Nebraska. The sampling period coincided with TNC's July 2012 “Week of Insects”, an event which involved both general public and invited expert participation, and was an opportunity for both education and citizen science. In four days of sampling, even under severe drought conditions, we encountered 22 species of ants. Fifteen species were found in never-plowed, remnant prairies, and four species were found only in them. Thirteen species were found on restored (planted) prairies, with three of these found only in the planted prairies. Four species were exclusively associated with mature cottonwood trees near the site headquarters.

Wild bee community change over a 26‐year chronosequence of restored tallgrass prairie

AbstractRestoration efforts often focus on plants, but additionally require the establishment and long‐term persistence of diverse groups of nontarget organisms, such as bees, for important ecosystem functions and meeting restoration goals. We investigated long‐term patterns in the response of bees to habitat restoration by sampling bee communities along a 26‐year chronosequence of restored tallgrass prairie in north‐central Illinois, U.S.A. Specifically, we examined how bee communities changed over time since restoration in terms of (1) abundance and richness, (2) community composition, and (3) the two components of beta diversity, one‐to‐one species replacement, and changes in species richness. Bee abundance and raw richness increased with restoration age from the low level of the pre‐restoration (agricultural) sites to the target level of the remnant prairie within the first 2–3 years after restoration, and these high levels were maintained throughout the entire restoration chronosequence. Bee community composition of the youngest restored sites differed from that of prairie remnants, but 5–7 years post‐restoration the community composition of restored prairie converged with that of remnants. Landscape context, particularly nearby wooded land, was found to affect abundance, rarefied richness, and community composition. Partitioning overall beta diversity between sites into species replacement and richness effects revealed that the main driver of community change over time was the gradual accumulation of species, rather than one‐to‐one species replacement. At the spatial and temporal scales we studied, we conclude that prairie restoration efforts targeting plants also successfully restore bee communities.

Thermal environment and microhabitat of ornate box turtle hibernacula

Box turtle populations are under significant threat from historic and current alterations of land‐use where remaining populations often occur in remnant patches of suitable habitat surrounded by a heterogeneous mixture of anthropogenically altered, unsuitable habitat. Ornate box turtles Terrapene ornata are a prairie‐dependent species, are considered Near Threatened by the International Union for Conservation of Nature (IUCN), and are Endangered or Threatened within many US states. Since their range exists largely in northern latitudes, aspects of hibernacula are particularly important for winter survival. How box turtles select hibernacula within prairies is likely of great importance to better understand which microhabitats are selected for and to identify areas of suitable habitat for management purposes. Using radio telemetry in conjunction with temperature dataloggers (iButtons), we examined the phenology and thermal characteristics of box turtle hibernation, and quantified microhabitat selection of their hibernacula in remnant prairie patches. We monitored hibernation initiation/termination phenology and turtle carapace temperatures, and quantified vegetative and soil microhabitat variables of hibernacula for seven turtles in 2014/2015 and 18 turtles in 2015/2016. Box turtles initiated (descended into hibernacula) and terminated (ascended out of hibernacula) at similar time periods across two years. Although the ambient thermal environment consistently experienced temperatures below freezing, turtle hibernacula offered a buffer against those temperatures and thus the temperature of turtle carapaces never fell below freezing. Turtles selected microhabitat hibernacula with higher percentages of sand, leaf litter and bare ground, and lower percentages of clay, silt, shrubs and herbaceous ground cover. Our study suggests the phenology of box turtle hibernation may be similar across years and that hibernacula selection is driven by above‐ and belowground characteristics that ultimately lead to a more stable and warmer thermal environment.

Ecosystem carbon pools, fluxes, and balances within mature tallgrass prairie restorations

AbstractTallgrass prairie restorations can quickly accrue organic C in soil and biomass, but the rate of C accumulation diminishes through time and is highly variable among more mature prairies. Long‐term soil organic carbon (SOC) accumulation in prairies has been linked to edaphic factors such as soil texture, soil moisture, and SOC content, but it is unclear how these factors affect the ecosystem processes that are responsible for observed differences in C accumulation rates in older prairies. We measured belowground plant and SOC pools and fluxes within 27–36‐year‐old restored tallgrass prairies in order to quantify total C storage, determine the net ecosystem production of C (NEP‐C), and explore which edaphic factors influence the ecosystem processes responsible for divergent NEP‐C. We found that 11% of organic C was stored in biomass, and we estimate that one‐third of post‐restoration C sequestration has occurred in biomass, thereby highlighting biomass as a large but often overlooked C pool. Belowground biomass and soil C pools were notably smaller than those reported for remnant prairie, suggesting that future belowground C accumulation could still occur. During this study, the prairies appeared to be a net source of C, although the range of NEP‐C values encompassed zero. Sand content positively affected NEP‐C via increased belowground biomass production‐C inputs, and SOC negatively affected NEP‐C due to increased soil respiration C outputs. However, soil moisture had a smaller negative effect on soil respiration, indicating that both SOC and soil moisture play important roles in determining prairie C balance.

Restoration Implications of Land Management Legacy on Aboveground and Seed Bank Composition of North American Grasslands

Abstract A variety of nonprairie landscapes, including pastures, crop fields, and unmanaged seral ground, are being restored to native prairie on a yearly basis. Seldom is the seed bank associated with these nonprairie lands taken into account in the restoration process. We examine the seed bank potential of nonprairie lands and the relationship between aboveground vegetation and seed bank composition at the largest grassland restoration east of the Mississippi River, the Midewin National Tallgrass Prairie (U.S.A.), by surveying six land management histories: remnant prairie, restored prairie, new pasture, active pasture, old field, and crop field. Both aboveground vegetation and seed bank composition varied with land management history. However, species composition of aboveground vegetation differed significantly from the species composition of the seed bank irrespective of land management history. Aboveground vegetation carried a higher proportion of the seed bank flora than vice versa. In contrast to s...

Impact of Restoration and Management on Aggregation and Organic Carbon Accumulation in Urban Grasslands

Core Ideas Few studies have examined SOC accrual in restored urban grasslands. We examined SOC accrual in 14 restored and native grasslands in Chicago. Short‐term (&lt;7 yr) restoration increased microaggregate OC toward levels in native prairies. Longer‐term restoration did not improve total SOC or aggregate OC. Differences in SOC were linked to soil moisture, N, texture, and inputs of C4–C among sites. Understanding the patterns of soil organic carbon (SOC) accumulation in restored grasslands is necessary to determine their potential to sequester atmospheric CO2. Patterns of SOC accrual after grassland restorations are generally based on studies in former agricultural fields, and these studies show an increase in SOC and aggregated‐associated OC over time. In this study, we quantified SOC accrual in a series of restored grasslands situated within the matrix of the Chicago metropolitan region. Soil samples were collected from unmanaged (no restoration), short‐term (&lt;7 yr), and longer‐term restorations (&gt;10 yr) and from native prairie remnants located on Mollisols or Alfisols and analyzed using a combination of physical fractionation (aggregate size) and chemical measurements (organic C [OC], 13C/12C natural abundance). We found that (i) total SOC declined after restoration and remained significantly lower in restored than unmanaged soils, (ii) patterns of aggregate OC in longer‐term restorations were more similar to those in unmanaged than to prairie sites, and (iii) microaggregate OC levels and C4–C inputs into aggregate fractions were significantly higher in short‐ than longer‐term restorations. Thus, an increasing time under management did not enhance SOC accrual. For all sites, path models showed that SOC accrual was correlated with soil N, texture, and moisture, whereas C4–C inputs were significant model terms only in short‐term restorations and prairie sites. Taken together, these results indicate the need to consider inter‐relationships among vegetation and soil factors as influences on SOC accrual rather than simply time under management.

Are small, isolated prairie remnants effectively smaller than they look and getting smaller?1,2

Abstract To evaluate the floristic sustainability of three small, isolated tallgrass prairie remnants, spatial and temporal patterns of species and functional group (FG) composition, richness, diversity, and dominance were examined to determine whether there was divergence between edge (outer 10 m) and interior zones. These remnants, all protected and managed nature preserves, are rectangular in shape and range in area from 1.29 ha to 1.77 ha; each is bordered by cropland and unmanaged or mowed ruderal grassland. A stratified sampling design was established using permanently marked transects oriented perpendicular to the long axis of each site. Vegetation data were collected in 50 cm × 50 cm quadrats along each transect; prairies were resampled 5–6 yr following baseline data collection. The null expectations were no differences between edge and interior zones, no differences between edge type (crop and noncrop), and no change over time. Results from linear mixed-effects models identified significant diffe...

Reproductive morphology ofSynthyris bullii,a rare Midwestern endemic species, in association with habitat degradation1

North America, prairie and savanna remnants suffer from increased habitat degradation and structural changes (e.g., woody encroachment). Plant populations in remnant habitats may be threatened over time as a result of this degradation. Past studies have explored plant responses to such changes by focusing primarily on vegetative characteristics rather than reproductive ones. Our research uses a rare Midwestern endemic, Synthyris bullii, to determine if the morphology of reproductive structures is associated with habitat quality. Study populations were visited and categorized according to the level of observed woody encroachment: shaded, semishaded, and open. From each population, 20 individuals were selected to measure inflorescence size (i.e., inflorescence height and flower number) and flower size (e.g., lengths of petals, stamens, carpels). Data were explored by canonical discriminant analysis to determine if traits were associated with particular habitat types and then analyzed by MANOVA and univariate ANOVAs to determine differences in traits among habitats. Results showed that floral morphometrics differed in open and shaded habitats, though semishaded habitats did not generally differ from the other two categories. Specifically, shaded habitats produced smaller inflorescences (e.g., fewer flowers) with larger flowers (e.g., increased lengths of petals and carpels), while the inverse pattern was observed in open habitats. Although we initially predicted consistent reductions in size across reproductive traits, we found instead inverse size patterns at the inflorescence level versus the flower level in different habitats. Our study highlights the impact of habitat changes that could ultimately affect the reproductive success of S. bullii and contribute to its decline.

Selection of fungi by candidate cover crops

Diversified cropping systems that incorporate year-round ground cover, are known to maintain healthy soils. Information is available for producers regarding the benefits of specific cover crop species for soil fertility, weed and pest management. Even though it is widely recognized that cover crops promote microbial biomass and activity, the specific responses of particular microbial groups to specific cover crop treatments are yet to be understood. In this work we determined differences in diversity and relative abundance of root endophytic fungi recovered by four potential cover crop species grown in a microbe-rich soil inoculum. For this, a trap culture approach was used, were plants of four species were grown in the greenhouse until maturity in a soil mix originating from a prairie remnant. Root endophytic fungi were surveyed through amplicon sequencing of total root DNA, targeting universal fungal and arbuscular mycorrhizae (AM) – specific ribosomal markers. Each host species studied enriched for different fungal community assemblages, with particular fungal lineages being differentially abundant across hosts. In general, wheat enriched for the greatest diversity of fungi, whereas vetch and clover were best for enrichment of AM fungi and oat for saprotrophs. Specific groups of fungi more abundant in wheat roots included members of the Sordariomycetes, mainly represented by the families Lasiosphaeriaceae, Magnaporthaceae and the order Pleosporales; whereas vetch recovered greater abundance of Hypocreales-like sequences, highly represented by the genus Ilyonectria. Within AM fungi differences in taxa recovery were observed between the orders Glomerales and Diversisporales across hosts, being these groups more abundant in wheat and vetch roots, respectively. From a fungal perspective, the direct benefits of the cover crop species (or species mix) in the cash crop will relate to the life history characteristics of the fungal communities preferentially colonizing each cover crop host.

Ecosystem services and tradeoffs in the home food gardens of African American, Chinese-origin and Mexican-origin households in Chicago, IL

AbstractWith increasing urbanization and environmental degradation, urban landscapes are increasingly expected to provide a wide range of ecosystem services typically associated with rural areas, including biodiversity conservation and food production. Because residential landscapes constitute the largest single urban land use, domestic gardens have emerged as a topic of research interest and planning concern. The ecosystem services (or disservices) these landscapes provide, however, have not been rigorously measured, nor have tradeoffs between the services they provide been assessed. In this study, semi-structured interviews were conducted with 59 African American, Chinese-origin or Mexican-origin households with on-lot or vacant lot food gardens in Chicago. Crop plants and cultivated ornamental plants on the lot were inventoried and mapped at the species level. A total of 123 edible plant taxa from 25 families and 288 ornamental plant species from 85 families were identified, for a combined total of 387 species from 90 families. Cumulatively, the gardens of African American households were relatively rich in ornamental plant species and families, while those of Chinese-origin households had a depauperate flora. Crop plant richness was more even across sample types. Shade trees and a developed shrub layer were absent from most gardens, possibly representing a tradeoff in ecosystem services in favor of food production. The richness of the aggregate 2.1 ha of residential property inventoried in this study was comparable with or exceeded that of a 34 ha prairie remnant west of Chicago. However, only 35 (9.6%) of the inventoried species were native to the Chicago area.

The pace of plant community change is accelerating in remnant prairies.

Patterns of biodiversity are changing rapidly. "Legacy studies" use historical data to document changes between past and present communities, revealing long-term trends that can often be linked to particular drivers of ecological change. However, a single pair of historical samples cannot ascertain whether rates of change are consistent or whether the impact and identity of drivers have shifted. Using data from a second resurvey of 47 Wisconsin prairie remnants, we show that the pace of community change has increased with shifts in the strength of particular drivers. Annual rates of local colonization and extinction accelerated by 129 and 214%, respectively, between 1950 and 1987 and between 1987 and 2012. Two anthropogenic drivers-patch area and fire history-increased in importance between these periods. As the strength and number of anthropogenic forces increase, rates of biodiversity change are likely to accelerate in other ecosystems as well.

Urban Rights-of-Way as Reservoirs for Tall-Grass Prairie Plants and Butterflies.

Urban rights-of-way may be potential reservoirs of tall-grass prairie plants and butterflies. To determine if this is true, in 2007-2008, we conducted vegetation surveys of species richness and cover, and butterfly surveys of species richness and abundance, along 52 transmission lines and four remnant prairies in Winnipeg, Manitoba. We detected many prairie plants and butterflies within transmission lines. Some unmowed and infrequently managed transmission lines had native plant species richness and total percent cover of native plants comparable to that of similar-sized remnant tall-grass prairies in the region. Although we did not find significant differences in overall native butterfly numbers or species richness between rights-of-way and remnant prairies, we found lower numbers of some prairie butterflies along frequently mowed rights-of-way than within remnant tall-grass prairies. We also observed higher butterfly species richness along sites with more native plant species. By reducing mowing and spraying and reintroducing tall-grass prairie plants, urban rights-of-way could serve as extensive reservoirs for tall-grass prairie plants and butterflies in urban landscapes. Eventually, managing urban rights-of-way as reservoirs for tall-grass prairie plants and animals could contribute to the restoration of tall-grass prairie in the North American Midwest.