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Tallgrass prairie has been reduced to a fraction of its original extent, due to rapid conversion to other land use types, especially agricultural and urban. Restoration is a relatively new process to convert agricultural land back to communities dominated by native vegetation. We used a differential equations compartmental model to quantify changes between land use types, incorporating the impact of human population within the Midwestern tallgrass prairie ecosystem. We considered transitions between native prairie, prairie restored through the Conservation Reserve Program (CRP), agricultural, and urban land. We used historical data to determine parameter ranges. Sensitivity analyses emphasize the importance of increasing incentives for CRP enrollment as a means to restoring the tallgrass prairie ecosystem.

Conversion of cultivated land to grassland is globally practiced to reverse soil degradation, but belowground ecosystem response to restoration has never been compared between old and new world temperate grasslands. We used a chronosequence approach to model change in root biomass and quality (indexed by C:N ratio), microbial biomass and composition [indexed by phospholipid fatty acids (PLFAs)], soil aggregate structure, and soil C and N stocks in the South African Highveld and compared recovery of these variables to a grassland restoration chronosequence in the US tallgrass prairie. We hypothesized soil C recovery, and mechanisms promoting soil C and N accrual would be convergent between these distant temperate grasslands with similar growing season precipitation, history of cultivation, and undergoing restoration with C4-grasses. Total PLFA richness and concentrations of most microbial groups rose to represent uncultivated grassland in the highveld (similar to tallgrass prairie), but in contrast to tallgrass prairie, the fungi:bacteria ratio did not increase with restoration age. In the highveld, root biomass accumulation was lower, but root quality became more representative of the never-cultivated grassland than in restorations in tallgrass prairie. Soil aggregate recovery was slightly faster in tallgrass prairie, and the pattern of macroaggregate C recovery was divergent due to less depletion in cultivated soil and higher stock of C in the uncultivated soil relative to the highveld. More rapid restoration of total soil C and N stocks in the highveld was attributed to greater soil C saturation deficit at the onset of restoration, development of higher quality root systems that promote the microbial biomass and soil aggregation, and climate conditions (distinct periodicity of rainfall and high aridity) that likely impose more limitation to decomposition relative to the tallgrass prairie ecosystem.

Macroinvertebrates are increasingly used as indicators of wetland integrity and productivity. However, accurate interpretation of biological information depends on effective sampling methods, which are also preferably cost-effective. We compared sampling yield, precision, and cost-effectiveness of two traditional wetland sampling methods (dipnet, stove pipe corer) to a dipnet combined with a dropframe in wetlands in the Platte River Valley, USA. The dropframe method was designed to be more quantitative than standard dipnet techniques and to maximize capture of mobile taxa. We compared measures of macroinvertebrate community structure (e.g., abundance, richness, diversity) and function (functional structure, habitat associations), as well as processing time for each sampling technique in vegetated and non-vegetated habitats. Vegetated habitats harbored higher richness, diversity, abundance, and biomass of most invertebrates. The dipnet consistently yielded the lowest values in vegetated and non-vegetated habitats, suggesting that sampling with a dipnet alone can greatly underestimate macroinvertebrate populations and diversity. The corer and the dropframe yielded similar results, but the dropframe produced significantly higher richness values. While the dropframe appeared to be a good choice for sampling in these wetlands, sample processing times for this method were more than two times longer than the other methods. Results provide a basis for informed decisions regarding quantitative sampling of wetland macroinvertebrates.

Many biotic and abiotic factors influence recovery of soil communities following prolonged disturbance. We investigated the role of soil texture in the recovery of soil microbial community structure and changes in microbial stress, as indexed by phospholipid fatty acid (PLFA) profiles, using two chronosequences of grasslands restored from 0 to 19 years on silty clay loam and loamy fine sand soils in Nebraska, USA. All restorations were formerly cultivated fields seeded to native warm-season grasses through the USDA’s Conservation Reserve Program. Increases in many PLFA concentrations occurred across the silty clay loam chronosequence including total PLFA biomass, richness, fungi, arbuscular mycorrhizal fungi, Gram-positive bacteria, Gram-negative bacteria, and actinomycetes. Ratios of saturated:monounsaturated and iso:anteiso PLFAs decreased across the silty clay loam chronosequence indicating reduction in nutrient stress of the microbial community as grassland established. Multivariate analysis of entire PLFA profiles across the silty clay loam chronosequence showed recovery of microbial community structure on the trajectory toward native prairie. Conversely, no microbial groups exhibited a directional change across the loamy fine sand chronosequence. Changes in soil structure were also only observed across the silty clay loam chronosequence. Aggregate mean weighted diameter (MWD) exhibited an exponential rise to maximum resulting from an exponential rise to maximum in the proportion of large macroaggregates (>2000 μm) and exponential decay in microaggregates ( 53 μm) and the silt and clay fraction (

Wetlands historically provided many ecosystem servicesbut most have been lost or degraded through land conver-sion. Recent appreciation for wetland values and increas-ing ecotourism in the Central Platte River Valley (U.S.A.)has promoted restoration of wet meadow systems, al-though recovery patterns are not well known. We quanti-fied plant community structure in sloughs (deeper habitats)and adjacent margins (slightly higher elevation) of six wet-land sites, restored for 1–7 years at the onset of a 3-yearstudy, and three natural wetlands to assess recovery dy-namics. Plant community metrics recovered differentiallybetween habitats. Within restored margins, richness anddiversity showed aweak quadraticresponsewith time sincerestoration, indicating that both indexes overshoot naturallevels shortly following restoration. Within sloughs, rich-ness and diversity showed no change with time, suggestingthat recovery occurs more quickly in these deeper, moisterhabitats. Percent similarity of plant communities in resto-rations and natural wetlands increased linearly over time.However, ordinations of plant community compositionshowed that recovery was strongly influenced by site-spe-cific hydrology and that recovery may not be a linear tra-jectory toward natural systems. The analysis andinterpretation of plant community dynamics revealed sev-eral challenges to restoration assessment, including therole of interannual variability in precipitation, limitationsto hydrologic recovery, and temporal variability in plantcommunity structure in natural systems that resulted in‘‘moving targets’’ for recovery comparisons. Temporal var-iability in climate must be considered when assessing res-toration success in systems where plant communitystructure is responsive to variable moisture regimes.Key words: assessment, Platte River, slough, temporalvariability, vegetation, wet meadow.IntroductionWorldwide, 53% of wetlands have been lost (Mitsch G U.S. Fish and Wildlife Service 1997). The severedegradation of wetlands in the PRV is of particular con-cern because this region is extensively used by migratorybirds on the central flyway to acquire energy and nutrientsessential for migration and reproduction (U.S. Fish andWildlife Service 1997). Seven to nine million individuals of300 bird species, including the federally endangered Inte-rior Least Tern (Sterna antillarum) and Whooping Crane(Grus americana),migrate annually alongthis route(Krapuet al. 1984; Currier et al. 1985; Austin & Richert 2001).Heightened awareness of the wetland services and theextent of loss and degradation of wetland habitats hasresulted in increased efforts to protect remaining systemsand spawned widespread restoration efforts. Followingthe removal of anthropogenic disturbance (e.g., ceasingcrop production), recovery of some ecosystem aspectsoccurs through natural succession (Dormaar & Smoliak1985; Burke et al. 1995; Ihori et al. 1995). However, natu-ral recovery often requires extensive time. Therefore,restoration aims to catalyze natural recovery processesthrough habitat manipulations (e.g., returning hydrology)(Wilcox et al. 2006), reintroduction of historic plant spe-cies (e.g., seeding) (Reinartz & Warne 1993), and/or man-agement (e.g., prescribed fire) (Clark & Wilson 2001).Plants are often the focus of wetland restorations (e.g.,Willard et al. 1990; Reinartz & Warne 1993; Galatowitsch& van der Valk 1996a) because vegetation is tightly cou-pled to wetland function (Mitsch & Gosselink 2000).Although restoration is a labor-intensive process in thePRV, evaluations of these restorations have been limitedin frequency, duration, and scope (but see Currier 1994;Whitney 1997; Currier 1998).

Wetlands in the central Platte River basin provide numerous ecosystem services but have been diminished and degraded by agricultural practices and development. Wetland restoration is increasingly common in this region, but the success of restorations is virtually unknown. We sampled macroinvertebrates during spring 2003 and 2004 in restored (5–16 y old) and natural slough wetlands to assess restoration success. Simple measures (e.g., total abundance, biomass, diversity) were all similar in restored and natural wetlands. Communities were similar in natural and restored wetlands, but we observed some taxonomic differences. For example, abundances of Helisoma and Pisidium and abundance and biomass of amphipods were higher in natural than in restored wetlands, and leeches were collected only in natural wetlands. These results suggest that dispersal ability is a biotic filter limiting recovery and that these noninsects are good candidates for assessing recovery. Functional structure on the basis of abu...

Wet meadows in the Platte River valley (PRV) consist of linear wetlands in mesic prairie matrix systems that have been degraded and diminished for agriculture. Restoration in this region is a widespread practice that involves land contouring and seeding native species, however ecosystem recovery following restoration has never been examined. We quantified recovery trajectories and rates of above- and belowground plant biomass, soil physical and chemical properties, and C and N pools in a chronosequence of six restored wet meadows in relation to three natural wetlands. Within each site, we sampled sloughs (deeper habitats) and adjacent margins (slightly higher elevation) for three consecutive years. Varying hydrologic regimes between habitats resulted in differential patterns in ecosystem measurements (bulk density, C mineralization) in both natural and restored wetlands. Total aboveground biomass (TAB), root biomass, root C and N storage, total soil C and N, microbial N, and extractable N increased with years restored in both margins and sloughs. The model predicted rates of increase did not differ between habitats, but elevations of linear regressions were higher in sloughs than margins for root N, total soil C, total soil N, MBN, and extractable total N (P < 0.05). Our results suggest that bulk density and soil organic matter (SOM) represent two useful, easily measured indices of ecosystem recovery, because they were correlated with many pools and fluxes of C and N. Furthermore, we conclude that most change in ecosystem structure and function during the first decade following restoration occurs in shallow soil depths, and ecosystem recovery varies with subtle differences in elevation and associated plant community structure.

Secondary production of the acridid community on Konza Prairie Biological Station, Kansas, was estimated to evaluate its significance to energy and nutrient cycling in annually burned and long-term unburned tallgrass prairie. A drop-trap and vacuum device were used to sample acridids on three watersheds in both the burned and unburned prairies during the 1998 and 1999 growing seasons. Production of common species was estimated using the instantaneous growth method, and consumption and egestion were estimated using ecological efficiencies. Total acridid abundance, biomass, and production estimates showed a trend of higher values on burned than on unburned watersheds during both years with significantly higher biomass and production on burned watersheds during 1998 (P < 0.05). Higher biomass and production on burned watersheds was primarily a result of higher values for graminivorous taxa. Forb-feeder and grass-feeder production was more similar on unburned than on burned watersheds, although responses of individual species varied greatly between the two watershed types and years. Grass-feeders and forb-feeders consumed an estimated 0.4-4.7 g ash-free dry mass (AFDM) m - 2 yr -1 of grass and 0.7-2.1 g AFDM m -2 yr -1 of forbs, respectively, depending on watershed type and year. Results indicate that acridids are important in nitrogen cycling. However, their relative importance to energy and nutrient cycling in tallgrass prairie varies with plant responses to burning and may be influenced by ungulate grazing.

The 1998 emergence of 17-y periodical cicadas (Magicicada cassini) on Konza Prairie Research Natural Area (KPRNA), Kansas, was quantified using emergence trap transects and counts of emergence holes. Emergence density, biomass (emergence production) and associated nitrogen flux were estimated for the entire 100 ha gallery forest of Kings Creek, the major drainage network on KPRNA. Emergence commenced on 22 May 1998 and lasted for 24 d, with 87% of the individuals emerging within the first 9 d. Males dominated early during the emergence, and the sex ratio for the entire population was estimated at 54:46 male:female. Average emergence abundance and biomass estimated from trap transects located in low areas where cicadas were most abundant were 152/m2 and 34.9 g ash-free dry mass (AFDM)/m2, respectively. Based on emergence hole counts, average density and biomass for the 59 ha of gallery forest where cicadas emerged were 27.2 individuals/m2 and 6.3 g AFDM/m2, and emergence hole densities >100/m2 wer...

Understanding processes that promote or constrain ecosystem recovery from disturbance is needed to predict the restorative potential of degraded systems. We quantified a suite of ecosystem properties and processes across two chronosequences of restored grasslands on contrasting soil textures to test the hypothesis that restorations on silty clay loam soil would exhibit greater recovery of soil carbon (C) and nitrogen (N) pools and fluxes than on loamy fine sand because soil with higher clay content possesses a greater capacity to physico-chemically protect organic matter. Warm-season grass aboveground net primary productivity was similar between the two soil textures. Root biomass increased and root quality (as indexed by C:N ratio) decreased across both chronosequences. An asymptote in the accumulation of N in roots in the silty clay loam chronosequence resulted in wider C:N ratios of roots than in the loamy fine sand chronosequence. Total soil C (TC) and microbial biomass C (MBC) increased across the si...