Ant Community Development on Rehabilitated Ash Dams in the South African Highveld

Ant communities have been widely used as indicators of minesite rehabilitation in Australia and are beginning to play a similar role in other parts of the world. Here we examine ant communities on rehabilitated ash dams associated with a coal‐fired power station on the highveld of South Africa, to improve our understanding of ecosystem development on these substrates. Ants were sampled using pitfall traps at 11 ash‐dam sites, ranging from unrehabilitated to 9‐year‐old rehabilitated sites, as well as two adjacent natural grassland sites. Sampling was conducted on 12 occasions from March 1997 to January 1999. Forty‐nine ant species from 19 genera were recorded during the study. Site species richness was positively correlated with rehabilitation age, ranging from 10 to 25 at ash‐dam sites, compared with 28 and 34 at the two natural grassland sites. There was a humped relationship between total ant abundance and rehabilitation age, with abundance peaking after 5–7 years at levels far higher than those at natural sites. Ordination analysis showed clear separation between ash‐dam and natural sites along the first axis. The unrehabilitated ash‐dam site was also separated from rehabilitated sites along the first axis. Sites of different rehabilitation age were separated along the second axis. Individual ant species showed clear successional patterns across the rehabilitation gradient. Although there was a clear successional trend for the development of ant communities on rehabilitated ash dams, this trend was not toward natural grassland. The lack of convergence toward ant communities of natural grasslands reflects the markedly different substrate and plant composition on ash dams and supports the widely held view that restoration of natural grassland communities is not a realistic goal of ash‐dam rehabilitation. However, the development of species‐rich ant communities, containing at least some late‐successional species, indicates the potential for rehabilitated ash dams to support diverse and complex ecosystems.     

Ant assemblages on rehabilitated tropical landfills

Ant assemblages have been used widely throughout the world except in Asia to assess land restoration. In this study, ant assemblages were studied on three rehabilitated landfills (closed for 11–26 years) and a mature woodland as reference in Hong Kong. Grassland and woodland areas on each landfill were examined separately. Ants were sampled by soil extraction, litter extraction and pitfall trapping to maximize capture efficiency. Simple vegetation measurements were also taken. A total of 64 ant species from 33 genera were recorded. Ant species richness in the three landfills was similar (25–30 species), which did not correlate with the age of rehabilitation. A relationship between ant species richness and various vegetation parameters was not observed. Cluster analysis separated the landfill sites from the reference site, and grassland sites from woodland sites. Composition of ants based on functional grouping differed on the grassland and woodland sites, and functional group composition also separated the landfill sites from the reference site. Ant functional groups but not species richness showed a successional pattern with the ecological development of landfills. However, even after more than 25 years of rehabilitation, the ant assemblages on landfills were still very different from that on the reference site.     

Responses of ant communities to dry sulfur deposition from mining emissions in semi‐arid tropical Australia,with implications for the use of functional groups

Abstract The impact of dry deposition of SO₂ emissions on ant abundance, diversity and composition was investigated at Mount Isa in the semiarid tropics of northern Australia. Forty plots were sampled, stratified at two levels: sulfur deposition zones (high, medium, low, and two control zones) and habitat (Ridge and Plain). The two habitats supported distinctly different ant communities. Ants had clear responses to SO₂ emissions. Ant abundance was lowest in the high and medium sulfur zones in both habitats. Species richness in high SO² plots (up to 5 km from the source) was approximately half that of control plots in Ridge habitat, and was substantially less than controls in the Plain habitat. Ant community composition in the high sulfur zone was clearly separated from those of other zones in ordinations. Vector fitting showed soil SO₄ concentration as a primary correlative factor in this separation. Ant abundance and richness were both negatively correlated with soil SO₄ concentration, and positively correlated with plant species richness and distance away from the smelters. The abundance of 10 of the 21 most common species showed significant responses to emissions. Five species showed positive responses, and all belong to species‐groups known to be abundant at disturbed sites throughout northern Australia. Relative abundance and richness of Eyrean (arid adapted) taxa collectively responded positively to sulfur, and Torresian (tropical) and Widespread species responded negatively. Despite large changes in species composition and abundances, there was relatively little change in the abundance of functional groups that have been widely used in studies of Australian ant communities. Ants are sensitive to SO₂ emissions and appear to be good candidates as an indicator group in this context. However, an alternative functional group framework is required for the identification of recurrent responses of arid zone ant communities to disturbance.     

Ants as ecological indicators of rainforest restoration: Community convergence and the development of an Ant Forest Indicator Index in the Australian wet tropics

Ecosystem restoration can help reverse biodiversity loss, but whether faunal communities of forests undergoing restoration converge with those of primary forest over time remains contentious. There is a need to develop faunal indicators of restoration success that more comprehensively reflect changes in biodiversity and ecosystem function. Ants are an ecologically dominant faunal group and are widely advocated as ecological indicators. We examine ant species and functional group responses on a chronosequence of rainforest restoration in northern Australia, and develop a novel method for selecting and using indicator species. Four sampling techniques were used to survey ants at 48 sites, from grassland, through various ages (1–24 years) of restoration plantings, to mature forest. From principal components analysis of seven vegetation metrics, we derived a Forest Development Index (FDI) of vegetation change along the chronosequence. A novel Ant Forest Indicator Index (AFII), based on the occurrences of ten key indicator species associated with either grassland or mature forest, was used to assess ant community change with forest restoration. Grasslands and mature forests supported compositionally distinct ant communities at both species and functional levels. The AFII was strongly correlated with forest development (FDI). At forest restoration sites older than 5–10 years that had a relatively closed canopy, ant communities converged on those of mature rainforest, indicating a promising restoration trajectory for fauna as well as plants. Our findings reinforce the utility of ants as ecological indicators and emphasize the importance of restoration methods that achieve rapid closed‐canopy conditions. The novel AFII assessed restoration status from diverse and patchily distributed species, closely tracking ant community succession using comprehensive species‐level data. It has wide applicability for assessing forest restoration in a way that is relatively independent of sampling methodology and intensity, and without a need for new comparative data from reference sites.     

Ants as Indicators of Restoration Success: Relationship with Soil Microbial Biomass in the Australian Seasonal Tropics

Ants are widely used as bioindicators in Australian land assessment and monitoring programs, particularly in relation to ecosystem restoration following mining. Little is known, however, about the relationship between ant community development and key ecological processes such as nutrient cycling. We have examined the relationship between ant species richness and soil microbial biomass at 17 sites subject to disturbance by mining in the Kakadu region of Australia's Northern Territory. The number of ant species recorded ranged from 7 at an unvegetated site undergoing restoration to 43 at a site that was undisturbed except for edge effects. Soil microbial biomass ranged from 19.3 to 134.3 μgC/g. Ant species richness was positively correlated with soil microbial biomass (r= 0.638), more so than was plant species richness (r= 0.342 for total plant species, r= 0.499 for woody species only). Our findings demonstrate a correlation between aboveground ant activity and belowground decomposition processes at disturbed sites, thereby providing support for the use of ants as indicators of restoration success following disturbance. Interestingly, when a range of undisturbed sites in the region was considered, a negative rather than positive relationship between ant richness and soil microbial biomass was found. This illustrates the importance of distinguishing between variation within a habitat due to disturbance and variation across different habitats when searching for indicators of ecological change.     

Ants as Indicators of Restoration Success at a Uranium Mine in Tropical Australia

The composition and structure of ant communities were used to assess the success of the preliminary restoration program at Ranger uranium mine in the seasonal tropics of northern Australia. Ants were surveyed at eight sites, including two relatively undisturbed control sits, within the Ranger lease. The revegetated sites represented a range of variables likely to influence restoration success: revegetation age (two, four, and eight years), proximity to undisturbed sites (which act as potential sources of recolonization), and burning treatment. Revegetation at most sites was dominated by fast-growing species of Acacia. There was a clear succession of ant species across revegetated sites. Initial colonization was by species of Iridomyrmex, but as plant cover and litter development increased these were replaced by broadly adapted, opportunist species, especially the introduced Paratrechina longicornis. Ant recolonization was very slow at isolated sites, with only 12 species present after eight years (the oldest site available). This compares with 21 species after only four years at a site located close to potential sources of recolonization. The ant community at this site, however, was very similar to that at another site located close to colonization sources, but eight years old. Ant succession therefore appeared to have stalled at this point, with species richness and composition bearing little resemblance to that at control sites. The heavy shade and litter produced by acacias were considered to be the major impediment to further change. Results from a site that had undergone a prescribed burn after two years, thereby breaking dominance by acacias and allowing for the establishment of a wide variety of plant taxa, suggest that such management practices may promote further colonization by ant species.     

The importance of sampling intensity when assessing ecosystem restoration: ants as bioindicators in northern Australia

Insects are commonly used as bioindicators for assessing ecosystem restoration, but such assessments are potentially influenced by sampling intensity. Uncommon species are often late colonizers of sites undergoing restoration, so that sampling that is effective for only common species can under‐represent differences between rehabilitation and reference sites. We found that differences in observed ant species richness and composition between rehabilitation and reference sites at a northern Australian uranium mine increased markedly with increasing sampling intensity (through repeat sampling), reflecting differences in the numbers of uncommon species. Ensuring appropriately high sampling intensity is important in assessments of restoration success using insect bioindicators.     

Recovery of ground ant (Hymenoptera: Formicidae) communities six years after a major environmental disaster

The recovery of ant communities at the Guadiamar River bank (southwest Spain) was studied across 5 yr, after an environmental disaster caused by the spill of toxic sludge over the river caused by a mine accident. Three affected and three control sites were sampled from 2000 to 2004 using pitfall traps. The last year of study, a more exhaustive sampling was conducted at the affected area (eight sampling sites). Additionally, four adjacent study sites not affected by the toxic spill were also studied. Ants showed clear responses to the restoration of the area. Mean ant species richness in spillage affected sites showed a significant increase over the 5 yr. Moreover, multivariate analysis showed distinct changes of ant community composition of the affected area over the years that were not observed in control sites. Six years after the disaster, one half of the species recorded in control sites were also present in the affected area, with only one species exclusive to this area, Cardiocondyla mauritanica Forel (tramp species). However, not only habitat specialist species but also some generalist and conspicuous species within the river basin are not present along the affected area, including species of the genera Camponotus, Messor, Cataglyphis, and Aphaenogaster. This study shows an incipient recovery of ant communities 6 yr after a major environmental disturbance, highlighting the absence of any invasive ant species in the restored area.     

Ants as Indicators of the Success of Rehabilitation Efforts in Deposits of Gold Mining Tailings

The evaluation of the success of restoration efforts is an essential step for environmental monitoring programs, providing reliable and intricate information on the response of biotic and abiotic elements of ecosystem following the restoration programs adopted. The aim of this study was to evaluate the efficacy of different rehabilitation efforts after gold mining activities using ants as bioindicators. We tested the following hypotheses: (1) the ant species richness and composition vary with the technique of revegetation and (2) the number of epigaeic and hypogaeic ant species increases with resources. We selected four tailing dumps from gold mining, one spontaneously revegetated (“Natural”) and the other three areas with different rehabilitation techniques, namely: Grassy 2005—rehabilitation with grasses in 2005; Grassy 2006—rehabilitation with grasses in 2006, and Shrubby 2004—rehabilitation with grasses, herbaceous, and shrubs in 2004. Ants were sampled using epigaeic and hypogaeic pitfall traps. Species accumulation curves show that the “Natural” area has a higher number of species. We found differences in species composition of epigaeic and hypogaeic ants among the different areas sampled. We conclude that Camponotus fastigatus can be taken as a good indicator of environmental rehabilitation in areas impacted by mining activities. Moreover, Ectatomma edentatum, Dorymyrmex brunneus, Crematogaster evallans, and Solenopsis invicta can also indicate that the rehabilitation process is not yet completed.     

Conservation value of low fire frequency in tropical savannas: Ants in monsoonal northern Australia

The conservation values of ‘old‐growth’ forests in landscapes subject to repeated disturbance by fire or logging have received considerable conservation attention. However, little is known of the conservation values of old‐growth sites in ecosystems with an evolutionary history of highly frequent disturbance. Here we address the value of low fire frequency (<1 fire/10 years) in tropical savannas, the world's most fire‐prone biome, in terms of ant biodiversity. We do this by comparing savanna ant communities within the Territory Wildlife Park (TWP) near Darwin in the Australian monsoonal tropics, which has experienced a low incidence of fire over 25 years due to active fire exclusion, with those of adjacent (outside) sites experiencing the ambient fire regime of burning every 2–5 years. Ants were sampled using terrestrial and arboreal pitfall traps at 16 sites, eight each inside and outside TWP. More than 16 000 ants were recorded during the study, representing a total of 98 ant species from 30 genera. More species in total were recorded outside (90) than inside (74) TWP, but there was no difference in mean site species richness or abundance, and overall species composition was similar. All species recorded inside TWP are common and widespread throughout the savanna landscapes of the broader region, in the absence of active fire exclusion. Low fire frequency at the Territory Wildlife Park therefore does not appear to have enhanced regional ant conservation values. Our findings reinforce the importance of targeting fire regimes that are clearly linked to positive conservation outcomes, rather than assuming a need for maximum ‘pyrodiversity’.     

The Effect of Logging on the Ground-Foraging Ant Community in Eastern Amazonia

In order to determine the suitability of ants as indicator organisms for habitat disruption in tropical forests, we studied the effects of both high and low impact logging on ant communities in northeastern Pará State, in the Brazilian Amazon. We collected ants from logged forests and unlogged forest sites with Winkler bags throughout the 1998 rainy season (January and April) and the following dry season (July and September). Both methods of timber harvesting showed impacts on ant community composition when compared with unlogged forest, although these impacts did not include modifications in total species richness or the relative contribution of each ant subfamily to the total number of species. Instead, logging induced alterations took place at the level of species and genera. A 2-fold reduction in the dominance of ants of the highly diverse genus Pheidole was associated with forest alterations in high-impact logging sites. Thus, logging in Amazonia can be seen to promote species shifts in ant communities, without, however, altering species richness. Ants of the genus Pheidole are potentially useful indicators for forest disturbances resulting from timber extraction.     

Comparative Study of Ant Communities of Rehabilitated Mineral Sand Mines and Heathland, Western Australia

We conducted a survey of ants in April 1997 in seven rehabilitated (2- to 20-year-old) and three native heathland reference sites of the Renison Goldfields Corporation (RGC) Mineral Sands operations at Eneabba, Western Australia. We employed a variety of collecting methods, including pitfall trapping, litter and soil sampling, sweeping and beating of vegetation, and collecting by hand in the day and after dark, replicating those used by previous researchers in a similar study conducted in the same area in 1980. We found a total of 96 ant species representing 30 genera in 1997, compared with 46 species from 18 genera in 1980. Ant species richness increased with age of rehabilitation and exceeded that of heath controls by the time it reached 11 years. Ant species richness related to rehabilitation age was represented by a logarithmic curve, and the slope for current rehabilitation was steeper than that for the earlier rehabilitation studied in 1980. This probably reflects improved rehabilitation practices. Ordination of the sites in terms of ant species composition indicated differences between ant species in the rehabilitated sites studied in 1980 and 1997, and also between all rehabilitated sites and heath controls. Classification of the sites in terms of the distribution of ants across functional groups also indicated differences between rehabilitation and heath control sites. According to species composition and functional group profiles from rehabilitated and control sites, we concluded that although the current rehabilitation allows for a rapid return of ant species, even after 20 years the fauna still had not attained the composition of the original heath fauna.     

Species richness,equitability, and abundance of ants in disturbed landscapes

Ants are used as indicators of environmental change in disturbed landscapes, often without adequate understanding of their response to disturbance. Ant communities in the southeastern United States displayed a hump-backed species richness curve against an index of landscape disturbance. Forty sites at Fort Benning, in west-central Georgia, covered a spectrum of habitat disturbance (military training and fire) in upland forest. Sites disturbed by military training had fewer trees, less canopy cover, more bare ground, and warmer, more compact soils with shallower A-horizons. We sampled ground-dwelling ants with pitfall traps, and measured 15 habitat variables related to vegetation and soil. Ant species richness was greatest with a relative disturbance of 43%, but equitability was greatest with no disturbance. Ant abundance was greatest with a relative disturbance of 85%. High species richness at intermediate disturbance was associated with greater within-site spatial heterogeneity. Species richness was also associated with intermediate values of the normalized difference vegetation index (NDVI), a correlate of net primary productivity (NPP). Available NPP (the product of NDVI and the fraction of days that soil temperature exceeded 25 °C), however, was positively correlated with species richness, though not with ant abundance. Species richness was unrelated to soil texture, total ground cover, and fire frequency. Ant species richness and equitability are potential state indicators of the soil arthropod community. Moreover, equitability can be used to monitor ecosystem change.     

Long-Term Trends in Faunal Recolonization After Bauxite Mining in the Jarrah Forest of Southwestern Australia

Abstract Fauna serve a key role in many forest ecological processes. Despite this, few studies have considered long‐term faunal recolonization after mining and rehabilitation of forest ecosystems. In the jarrah forest of southwestern Australia, permanent fauna monitoring sites have been established in bauxite mined areas rehabilitated in 1990 and in a range of representative unmined forest control sites. At each site mammals, birds, reptiles, and ants were surveyed in 1992, 1995, and 1998. The aims of the monitoring were to develop a better understanding of faunal recolonization trends, to produce recommendations for promoting fauna return, and to consider which techniques and fauna groups are best suited for monitoring recolonization. The results showed that successional trends varied between fauna groups. Generalist foraging mammals recolonized rapidly, whereas small predators took longer. Feral mice were initially abundant and then declined. Birds gradually recolonized, and after 8 years bird communities were very similar to those in unmined forest sites. Reptile species took longer, and after 8 years numbers of species remained lower than in unmined forests. Species richness and diversity of ants in 8‐year‐old rehabilitation were comparable with those of unmined forest in some rehabilitated sites but were lower in others. The composition of ant communities was still different from that of unmined sites. Ant species that only use disturbed forest declined rapidly in abundance as rehabilitation aged. The results suggest that although the rates of faunal recolonization will vary, with time most or all mammal, bird, reptile, and ant species should inhabit rehabilitated bauxite mines. The densities of many are likely to be similar to those in unmined forest, but for others it is too early to know whether this will be the case. Techniques for promoting fauna return are discussed. This study demonstrates that no single fauna group is suitable for use as an overall “indicator” of faunal recolonization; different fauna species and groups reflect different aspects of faunal succession.     

Ant Diversity and Abundance along an Elevational Gradient in the Philippines1

Ant communities were surveyed along an elevational gradient in the Philippines extending from lowland dipterocarp forest (250 m elevation) to mossy forest (1750 m). Standardized pitfall trapping in arboreal and terrestrial microhabitats at seven sites yielded 51 species. Collecting by hand at five of the sites yielded 48 species. The two methods produced substantially different assemblages, with only 22 species (29%) taken in common. Only a fraction of the total ant community appeared to be sampled at most of the sites. Measures of species richness and relative abundance peaked at mid-elevations and declined sharply with increasing elevation. Ants were extremely rare above 1500 m elevation. Arboreal ants were trapped much less frequently than terrestrial ants at all sites. Ant species that were abundant had broader elevational distributions than those that were less common, but most species were rare and occurred at only one or two sites. The elevational patterns for ants are largely the inverse of those documented for Philippine small mammals which reach their greatest diversity and abundance at high elevations where ants are rare. This suggests that the two groups may interact competitively. Some of the patterns observed or inferred from this study may apply to tropical ant communities in general, and are presented as series of testable hypotheses as a guide and stimulus for future research.     

Contrasting Effects of Fire on Arboreal and Ground‐Dwelling Ant Communities of a Neotropical Savanna

Ants are a dominant group in tropical savannas and here we examined the responses of the arboreal and ground‐dwelling ant fauna to a fire in a Neotropical savanna (cerrado) reserve in Central Brazil. Ants were collected using pitfall traps and baits placed in trees and on the ground beneath each tree. Of the 36 trees marked along two transects, half (from each transect) were burned and half not. The same trees were sampled 1 wk before and again 3 and 12 mo after the fire. Rarefaction curves and ordination analyses using data from all trees from each side of each transect indicated that overall ant species richness and composition did not change after fire. Fire, however, reduced the mean number of ant species per tree, and increased the mean number of species on the ground. Fire increased the average abundance of specialist predators, Camponotini, and opportunistic species, and decreased that of arboreal specialists. Changes in the ground‐dwelling fauna were only detected 12 mo after the fire, while those in the arboreal fauna occurred earlier and were no longer apparent 12 mo after the fire. We suggest that these contrasting results represent mainly an indirect response of the ant communities to fire‐induced changes in vegetation. Given the temporary and small scale nature of the effects detected and the overall resilience of the ant fauna, our results indicate that a single fire in the cerrado vegetation does not greatly impact the structure of ant communities in the short term.     

Long‐term regeneration of a tropical plant community after sand mining

Sandy coastal plant communities in tropical regions have been historically under strong anthropic pressure. In Brazil, these systems shelter communities with highly plastic plant species. However, the potential of these systems to regenerate without human assistance after disturbances has hardly been examined. We determined the natural regeneration of a coastal sandy plain vegetation (restinga) in Brazil, 16 years after the end of sand removal. We inventoried 38 plots: 20 within a sand‐mined site and 18 in an adjacent undisturbed site. We expected lower diversity values in the sand‐mined site compared to the undisturbed site, but similar species composition between the two sites due to the spatial proximity of the two sites and the high plasticity of restinga species. Species were ranked using abundance and importance value index in both sites, and comparisons were performed using Rényi entropy profiles, rarefaction curves, principal component analysis, and redundancy analysis. Species composition and dominant species differed markedly between the two sites. Bromeliads and Clusia hilariana, well‐known nurse plants, dominated the undisturbed site but were almost absent in the regenerating site. Species richness did not differ between both sites, but diversity was higher in the undisturbed site. Within‐site composition differences in the mined area were associated with field characteristics. Interestingly, species classified as subordinate or rare in the undisturbed site became dominants in the regenerating site. These newer dominants in the sand‐mined site are not those known as nurse plants in other restingas, thus yielding strong implications for restoration.     

A six-year experimental restoration of biodiversity by shrub-clearing and grazing in calcareous grasslands of the French Prealps

The conservation of dry calcareous grasslands in the French Prealps strongly depends on the maintenance of low-intensity farming systems supported by agri-environmental schemes. An experimental assessment of the effect of current agro-pastoral management on the biodiversity of plant communities was conducted during a six-year permanent plot survey in four sites with contrasting habitat conditions (mesic to xeric). Analyses of species changes showed: (i) a strong increase in species richness and open grassland species frequencies four years after shrub-clearing, and (ii) a noticeable recovery of rare annuals and perennial species of conservation interest establishing in gaps created by grazing. At the community level, the restoration effect was evaluated by a between-year Correspondence Analysis, explaining 10.9% of the total floristic variability versus 29.5% for the site effect (between-site CA). Species ordination by between-year CA showed similar trajectories of vegetation changes during restoration despite different habitat conditions and grazing regimes between sites. The successful restoration of prealpine calcareous grasslands was explained by the availability of seed sources during the study in adjacent grazed or mown grasslands. Thus, restoration assessment should focus on dispersal possibilities and functional roles of species rather than species richness only. Finally, the spatial (i.e. the area of patches that need to be restored) and temporal (i.e. the frequency of shrub-clearing) implications for the large-scale conservation of prealpine calcareous grasslands by current agro-pastoral management are discussed.     

Ants show that the conservation potential of afforestation efforts in Chinese valley-type savanna is dependent upon the afforestation method

China has the largest afforestation effort in the world, which was implemented in response to large-scale deforestation that has occurred over centuries. Although the outcomes for vegetation coverage are clear, it remains unclear if these efforts also translate into broader conservation outcomes for fauna. Here we use ant communities to assess the conservation potential of vegetation undergoing natural regeneration and subject to afforestation plantings in valley-type savanna in the Hengduan Mountains of southwest China. Species richness was almost always highest in the oldest (30 year) sites irrespective of habitat type. The two sites that were monocultures of Leucaena leucocephala had notably low species richness (1 and 6 species respectively). Plant species richness had a significant positive relationship with total ant abundance and richness. The number of exotic ant species present had a negative relationship with total species richness. Multivariate analysis of species presence/absence data found no distinction between ant communities of plantation and rehabilitating sites, except for the two Leucaena plantation sites. PCA analysis of abundance data found that the separation of the sites was dependent upon the analyses conducted. We conclude that afforestation efforts are a useful conservation tool, regardless of whether these are of regenerating purely native vegetation or the creation of novel ecosystems using non-native species. However, for plantations the conservation benefits are dependent upon the species that are planted.     

Recovery of Native Plant Community Characteristics on a Chronosequence of Restored Prairies Seeded into Pastures in West‐Central Iowa

Restored grasslands comprise an ever‐increasing proportion of grasslands in North America and elsewhere. However, floristic studies of restored grasslands indicate that our ability to restore plant communities is limited. Our goal was to assess the effectiveness of restoration seeding for recovery of key plant community components on former exotic, cool‐season pastures using a chronosequence of six restoration sites and three nearby remnant tallgrass prairie sites in West‐Central Iowa. We assessed trends in Simpson's diversity and evenness, richness and abundance of selected native and exotic plant guilds, and mean coefficient of conservatism (mean C). Simpson's diversity and evenness and perennial invasive species abundance all declined with restoration site age. As a group, restoration sites had greater richness of native C₃ species with late phenology, but lower richness and abundance of species with early phenology relative to remnant sites. Total native richness, total native abundance (cover), mean C, and abundance of late phenology C₃ plants were similar between restoration and remnant sites. Observed declines in diversity and evenness with restoration age reflect increases in C₄ grass abundance rather than absolute decreases in the abundance of perennial C₃ species. In contrast to other studies, restoration seeding appears to have led to successful establishment of tallgrass prairie species that were likely to be included in seeding mixtures. While several floristic measures indicate convergence of restoration and remnant sites, biodiversity may be further enhanced by including early phenology species in seeding mixes in proportion to their abundance on remnant prairies.