Plant species diversity, plant biomass and responses of the soil community on abandoned land across Europe: idiosyncracy or above-belowground time lags

We examined the relationship between plant species diversity, productivity and the development of the soil community during early secondary succession on former arable land across Europe. We tested the hypothesis that increasing the initial plant species diversity enhances the biomass production and consequently stimulates soil microbial biomass and abundance of soil invertebrates. We performed five identical field experiments on abandoned arable land in five European countries (CZ, NL, SE, SP and UK) which allowed us to test our hypothesis in a range of climate, soil and other environmental factors that varied between the experimental sites. The initial plant diversity was altered by sowing seed mixtures of mid-successional grassland species with two or five grass species, one or five legumes and one or five forbs. The results of low and high sown diversity treatments were compared with plots that were naturally colonized by species present in the seed bank. In three out of the five field sites, there was no correlation between plant species number and plant biomass production, one site had a positive and the other a negative relation. Treatments with a high diversity seed mixture had a higher biomass than the naturally colonized plots. However, there was no significant difference between high and low sown diversity plots at four out of five sites. The three-year study did not give any evidence of a general bottom-up effect from increased plant biomass on biomass of bacteria, saprophytic fungi or abundance of microarthropods. The biomass of arbuscular mycorrhizal was negatively related to plant biomass. The abundance of nematodes increased after abandonment and was related to plant biomass at four sites. Our results support the hypothesis that plant species diversity may have idiosyncratic effects on soil communities, even though studies on a longer term could reveal time lags in the response to changes in composition and biomass production of plant communities.     

POPULATION STRUCTURE,BIOMASS ALLOCATION,AND PHENOTYPIC PLASTICITY IN MURDANNIA KEISAK (COMMELINACEAE)

Field and glasshouse studies were used to explain differences in plant biomass, shoot length, and reproductive effort in four populations of a wetland annual herb, Murdannia keisak. Populations were chosen from continually thermally disturbed, intermittently thermally disturbed, revegetating, and undisturbed portions of a floodplain forest in South Carolina, USA. Plants in the two thermally disturbed areas were shorter, flowered earlier in the autumn, and produced more and smaller seeds than plants in revegetating and undisturbed sites. Reproductive effort was higher in populations from undisturbed and revegetating sites than in the two thermally disturbed sites. Generally, differences observed in the field were not expressed in the glasshouse plants. Glasshouse experiments suggested that most of the observed among-population differences in size and reproductive effort in the field study were a result of a plastic response to water depth and light. The combination of field and glasshouse data showed that this wetland weed adjusts readily to newly disturbed habitats, thus spreading rapidly and maintaining local dominance.     

Evaluating soil seed banks of phosphate mining restoration in the hyper-arid Negev desert

Ecological systems are severely damaged by the anthropogenic disturbance of mining. Phosphate open-pit mining fields cover over 200 km² of the Negev desert, Israel. However, the effects of the ongoing mine site restoration efforts on the plant community have not been studied. Plants and their seed banks have a major role in ecosystem processes and restoration. In this study, we focused on three mining sites, restored in different years, along Zin River valley. We compared the plant community of restored mining plots within these areas to adjacent natural plots. We asked whether plant community germination potential from the soil seed bank differs between the restored plots and the adjacent natural plots within a mining site. We hypothesized that: (1) there is a lack of seed bank in the restored plots; (2) the altered soil composition at the restored plots inhibits germination. We used soil samples collected from the different mining sites and set up greenhouse experiments. One experiment compared natural and restored areas with different soil treatments. In another experiment, we added native seeds to test their germination potential on restored soil. Our results indicate that lack of seed bank is the major limiting factor hindering germination and not the composition of the soil after restoration. Our findings shed light on the constraints of seed bank establishment in post-mining areas of hyper-arid regions. We suggest considering active restoration practices to facilitate natural dispersal and improve seed bank establishment.     

Emergence of Eucalyptus marginata (jarrah) from seed in Mediterranean-climate forest in response to overstorey,site, seedbed and seed harvesting

Abstract The effects of overstorey, type of site, seedbed, seeding date and seed harvesting by vertebrates and invertebrates on the emergence of Eucalyptus marginata (jarrah) seedlings were studied experimentally in the northern jarrah forest of Western Australia. Seed harvesting by small vertebrates substantially reduced emergence, whereas invertebrates only slightly reduced emergence. Ninety per cent of seed was removed within 1 day when it was on the soil surface and in the open, whereas seed removal was insignificant when the seed was covered by soil. Vertebrates harvested seed more effectively when the understorey and litter were removed and the seed was more visible on the soil surface. Seed harvesting by small vertebrates had less impact on a site where there had been bauxite mining, possibly because the surrounding area was being revegetated with large numbers of seed and the area afforded poor cover for vertebrates. Emergence was less where the overstorey was removed compared to where it was retained, and on the rehabilitated bauxite mined site compared to the forest sites. There was no difference in emergence between the low and high quality forest sites and so the emergence phase could not fully explain the variation in abundance off. marginata seedlings on different quality sites. Post emergence events are likely to be important in explaining this difference between low and high quality sites.     

Plant Functional Type Effects on Trace Gas Fluxes in the Shortgrass Steppe

Plant community structure is expected to regulate the microbial processes of nitrification and denitrification by controlling the availability of inorganic N substrates. Thus it could also be a factor in the concomitant release of NO and N2O from soils as a result of these processes. C3 and C4 plants differ in several attributes related to the cycling of nitrogen and were hypothesized to yield differences in trace gas exchange between soil and atmosphere. In this study we estimated fluxes of NO, N2O and CH4 from soils of shortgrass steppe communities dominated by either C3 plants, C4 plants or mixtures of the two types. We collected gas samples weekly from two sites, a sandy clay loam and a clay, throughout the growing seasons of 1995 and 1996. Plant functional type effects on gas fluxes at the clay site were not apparent, however we found several differences among plant communities on the sandy clay loam. CH4 uptake from atmosphere to soil was significantly greater on C4 plots than C3 plots in both years. NO fluxes were significantly greater from C4 plots than from C3 plots in 1995. NO fluxes from C3 and mixed plots were not significantly different between 1995 and 1996, however fluxes from C4 plots were significantly greater in 1995 compared to 1996. Results indicate that under certain environmental conditions, particularly when factors such as moisture and temperature are not limiting, plant community composition can play an important role in regulating trace gas exchange.     

Experimental evidence for a delayed response of the above-ground vegetation and the seed bank to the invasion of an annual exotic plant in deciduous forests

Invasions by alien plants significantly affect native biodiversity and ecosystem functioning. We conducted a 5-year field experiment to investigate potential effects of the annual invasive plant Impatiens glandulifera on both the native above-ground vegetation and the soil seed bank in a deciduous forest in Switzerland. Eight years after the establishment of I. glandulifera, we set up plots in patches invaded by the alien plant, in plots from which the invasive plant had been manually removed and in plots which were not yet colonized by the invasive plant. We examined plant species richness, diversity and plant species composition in the above-ground vegetation and soil seed bank in all plots one year and five years after the initiation of the experiment. The 36 plots (3 plot types × 6 replicates × 2 sites) were equally distributed over two forest sites. Neither the native above-ground vegetation nor the soil seed bank was influenced by the presence of I. glandulifera one year after the start of the field experiment. After five years, however, plant species richness of both the above-ground vegetation and the soil seed bank was reduced by 25% and 30%, respectively, in plots invaded by the alien plant compared to plots from which I. glandulifera had been removed or uninvaded plots. Furthermore, plots invaded by the alien plant had a lower total seedling density (reduction by 60%) and an altered plant species composition in the soil seed bank compared to control plots. Our field experiment indicates that negative effects of the annual invasive plant on the native above-ground vegetation and soil seed bank of deciduous forests become visible with a delay of several years.     

Effects of elevated nitrogen and exotic plant invasion on soil seed bank composition in Joshua Tree National Park

We investigated the effects of exotic species invasion and 3?years of nitrogen (N) fertilization on the soil seed bank in Joshua Tree National Park, California, USA at four sites along an N deposition gradient. We compared seed bank composition and density in control (no N added) and fertilized (30?kg?N?ha^?1?year^?1) plots to determine if the seed bank would reflect aboveground changes due to N fertilization. Soil samples were collected and germinated in a greenhouse over 2?years. In the field, invasive species cover responded positively to N fertilization. However, we did not observe increased seed density of exotic invasive species in fertilized plots. While no significant differences were detected between treatments within sites, exotic invasive grass seeds overwhelmed the seed bank at all sites. Significant differences between sites were found, which may be due to differences in level of invasion, historic N deposition, and soil surface roughness. Sites experiencing low N deposition had the highest seed bank species richness for both control and fertilized treatments. Aboveground plant density did not correlate well with seed bank density, possibly due to the inherent patchiness of soil seed banks and differential ability of species to form seed banks. This seed bank study provided insight into site-specific impacts on native versus invasive species composition of soil seed banks, as well as magnitude of invasion and restoration potential at invaded sites.     

Endozoochory by free-ranging, large herbivores: Ecological correlates and perspectives for restoration

Seed dispersal via ingestion and defecation by large herbivores provides a possible aid for ecological restoration of plant communities, by connecting source communities of target species with habitat restoration sites. It is also a possible threat due to invasion of weeds, grasses or exotic species. Insight into the factors determining internal seed dispersal could therefore improve the management of grazed ecosystems.

We recorded viable seed density in cattle, sheep and pony dung samples and monitored dung pat colonisation in the field. In addition, we counted the distribution of dung pats in plots spread over all habitat units in our study site.

The three herbivore species appeared to disperse large quantities of many species (61 in total) from a variety of plant families, monocots as well as dicots. The density of viable seeds in herbivore dung and the colonisation of dung pats were positively correlated with Ellenberg nitrogen indicator values and seed supply, but not with seed mass or shape.

The results imply that many seeds are dispersed from high productive to low productive parts of the grazed area. In free-ranging systems, we therefore recommend enclosure and separate management of plant communities on nutrient-poor soils with high conservation interest. For habitat restoration sites we recommend integrated grazing only with target plant communities on nutrient-poor soils and not with plant communities on nutrient-richer soils.     

Manganous oxide as a seed-pellet additive for controlling manganese deficiency in sugar-beet seedlings

Summary Experiments in the laboratory, glasshouse and field during 1975–78 tested manganous oxide as a seed-pellet additive for controlling deficiency in sugar-beet seedlings. There was no experimental evidence that manganous oxide in the seed pellet was ever harmful to seedling establishment. On the contrary, germination tests in the laboratory and experiments in the glasshouse indicated that, in certain conditions, manganous oxide may improve plant establishment even when plants are not likely to be deficient, probably by accelerating germination of seed and emergence of seedlings. In field experiments where sugar beet were severely deficient, the plants were heavier and contained more manganese on plots sown with seed pelleted with material containing 50% manganous oxide than on plots sown with ordinary pelleted seed. Applying a foliar spray of manganese sulphate during the third week of June in addition to pelleting the seed with material containing manganous oxide gave bigger yields than either the seed-pellet treatment or foliar spraying alone.     

The seed banks of English lowland calcareous grasslands along a restoration chronosequence

We investigated whether the seed banks of ex-arable lowland calcareous grasslands underwent restoration similar to that of the above-ground restoration, and whether this was influenced by seed-sowing or environmental conditions. We compared 40 sites, where some form of restoration work had been implemented between 2 and 60 years previously, with 40 paired reference sites of good quality calcareous grassland with no history of ploughing or agricultural improvement. We analysed differences between sites and between above- and below-ground vegetation using both a multivariate approach and proportions of selected plant attributes. Seed banks of reference sites were more characteristic of late successional communities, with attributes such as stress tolerance, perenniality and a reliance on fruit as the germinule form more abundant than in restoration sites. In restoration sites, these tended to decrease with restoration site isolation and increase with restoration site age and where soil nutrient conditions were more similar to reference sites (i.e. with relatively low phosphorus and high nitrogen). Seed bank communities of all sites differed considerably from above-ground communities, however, and no overall significant responses to site age, isolation or soil nutrients were detected by multivariate analyses of similarity of species between pairs of sites. Responses to different seeding methods were also barely detectable. While there is some indication from the plant attribute data that the regeneration potential contained in the seed banks of restored sites increasingly resembles that of references sites over time, even seed banks of good quality calcareous grassland are dominated by ruderal species. It is likely, therefore, that permanent seed banks do not facilitate the restoration of ex-arable grasslands.     

Contrasting Effects of Substrate and Fertilizer Nitrogen on the Early Stages of Litter Decomposition

Commonly observed positive correlations between litter nitrogen (N) concentrations and decomposition rates suggest that N frequently limits decomposition in its early stages. However, numerous studies have found little, if any, effect of N fertilization on decomposition. I directly compared internal substrate N and externally supplied inorganic N effects on decomposition in sites varying in soil N availability. I decomposed eight substrates (with initial %N from 0–2.5) in control and N-fertilized plots at eight grassland and forest sites in central Minnesota. N fertilization increased decomposition at only two of eight sites, even though decomposition was positively related to litter N at all sites and to soil N availability across sites. The effect of externally supplied N on decomposition was independent of litter N concentration, but was greater at sites with low N availability. The inconsistent effects of substrate and externally supplied N may have arisen because decomposers use organic N preferentially as an N source; because inorganic N availability across sites or with fertilization induced changes in microbial community attributes (for example, lower C:N or greater efficiency) that reduced the response of decomposition to increased inorganic N supply; or because the positive correlation between litter N or site N availability with decomposition was spurious, caused by tight correlations between litter or site N and some other factor that truly limited decomposition. These inconsistent effects of substrate N and external N supply on decomposition suggest that the oft-observed relationship between litter N and decomposition may not indicate N limitation of decomposition.     

Seed dispersal in Cakile edentula var. lacustris : decoupling the fitness effects of density and distance from the home site

A factorial design of three densities of siblings at three local distances from seed parents was employed to distinguish effects of density from effects of dispersal distance on lifespan and fruit production of Cakile edentula var. lacustris, a plant with heteromorphic seeds. The segmented fruits produce two seed types: proximal and distal, with distal seeds having greater mass and greater dispersibility. Effects of longer distances (0.5 km and 30 km) on lifespan and fruit production were investigated using plants at low density. The prediction was tested that the greater seed mass of distal seeds increases fitness when seeds are dispersed into sites of unknown quality away from the home site or when seeds are dispersed to low density. High density caused earlier mortality and lower probability of reproduction. Distance from the maternal plant did not influence lifespan or reproduction at distances of 15 m or less, but lifespan was longer 0.5 km from the home site. No interaction was detected between the effects of density and distance on either lifespan or total fitness. Environmental conditions that influence fitness did not vary as a function of dispersal distance in this system, and favorable conditions at the home site did not persist between generations. Therefore, selection on dispersion patterns in natural conditions is likely to be through effects of density rather than dispersal distance. Proximal seeds had greater reproduction than distal seeds at the home site, and distal seeds had greater reproduction at the more distant sites (but not the most distant site), as expected, but these performance differences could not be attributed to differences in mass between the two seed types. Reduced seed mass was favored at the most distant site, but larger seed mass was favored most strongly at low density. Seeds that are dispersed to low density are larger, suggesting that although kin selection may limit the effectiveness of individual selection to increase seed mass under conditions of sibling competition, density-dependent individual selection on seed mass, rather than distant-dependent selection, also contributes to the observed associations among seed type, seed mass and dispersal ability. Received: 21 October 1996 / Accepted: 4 December 1996     

Phenotypic plasticity and population differentiation in seeds and seedlings of the grass Anthoxanthum odoratum

Summary Seeds of Anthoxanthum odoratum were transplanted reciprocally between a xeric and a mesic field population that were genetically differentiated in adult traits. In one experiment seeds were reciprocally buried in bags in the soil, in a second experiment seeds were reciprocally sown in small plots. For most traits, site effects were much larger than seed-source effects. Germination, emergence, mortality of buried seed and recruitment were significantly higher at the xeric site than at the mesic site, irrespective of population of origin. Seed dormancy, was significantly higher for seed originating from the mesic than from the xeric population. Seedling recruits originating from the xeric population tended to be larger at both sites. Fecundity of seedling recruits depended on the environment; fecundities of plants growing in the xeric site had more than double the fecundity of plants growing in the mesic site. Phenotypic plasticity rather than population differences determined variation in performance in the seed and seedling stages.     

Safe Site and Seed Limitation in Cytisus Scoparius (Scotch Broom): Invasibility, Disturbance, and the Role of Cryptogams in a Glacial Outwash Prairie

In all plant populations, establishment is controlled by two factors: the supply of propagules and their access to ‘safe sites’ for growth. An infestation of invading pest plants results in a seed-production gradient, from the edge where seeds are limiting, to the center where seeds may be in excess. Do invaded sites become ‘saturated’ with seeds? How rapidly does this occur, and how does the process depend on the availability of safe sites? Are safe sites, and consequently invasion, promoted by disturbance? I quantified the response of seedling establishment to seed input and disturbance in Cytisus scoparius (Scotch broom), an exotic shrub invading glacial outwash prairie remnants in western Washington, USA. I used disturbance treatments to investigate the role of the thick cryptogamic layer in these prairies, disturbing cryptogams by scraping or by fire. The effect of fire was partitioned into two factors: burning of the background vegetation/substrate versus breaking C. scoparius seed dormancy, by adding seeds either before or after the burn. Seed treatments ranged from 20 to 1000 seeds per m². Both seed number and surface treatment showed significant effects on seedling density, along with a significant interaction between the two factors. Disturbance did not promote C. scoparius establishment; undisturbed plots produced more seedlings than burned or scraped plots. Within the burned plots, fire scarification appeared to increase germination but this effect was not significant. For germinated seedlings, mortality through the dry season (June–August) was not significantly different among surface treatments, nor did survivorship depend on density, with the result that initial differences in germination among the treatments persisted. The message that the undisturbed cryptogam layer facilitates C. scoparius establishment suggests that ‘ecosystem management’ strategies promoting healthy, undisturbed sites will not always be effective against invasive pest species.     

Spontaneous and initiated succession on unvegetated slopes in the abandoned lignite‐mining area of Goitsche,Germany

Abstract. In this study, we examined the colonization of unvegetated, dry slopes in the lignite‐mining area of Goitsche, Germany. The plots, characterized by different habitat conditions, were studied from 1994–2000. The vegetation development on treated plots was compared to untreated plots showing spontaneous succession. For initial treatments we used fresh plant clippings from a species‐rich sandy grassland (Armerion elongatae) mowed at the end of July. Soil seed bank samples, taken at the beginning of the experiments and cultivated for 18 months, confirmed that the vegetation development on the slopes started with primary succession. Because seed rain is considered to be an important factor in primary succession, we also studied the diaspore input during the first year. The hospitable Quaternary substrate of Site I (pH = 4.1–4.7, 92 % sand) supports fast vegetation development on treated and untreated plots. On treated plots, we have identified plant assemblages similar to initial stages of the Armerion elongatae community. On control plots, Coryne‐phorion communities have established spontaneously. At Site II (mixed Quaternary and Tertiary substrate, pH = 3.0–3.5,40 % sand) the total cover and number of psammophytic species was low. Treated plots showed development towards ruderal sandy grassland, but the establishment of Calamagrostis epigejos would eventually lead to monodominant stands. Untreated control plots showed basically the same pattern, however the development was slower. At Site III (pH = 1.8–2.8, 34 % sand), the hostile Tertiary substrate impeded the succession on both treated and untreated plots because low pH and therefore high amounts of Al³⁺ produced elemental toxicity to plants. The application of plant clippings accelerated the vegetation development in sites with a pH exceeding 3. On plots with the initial treatment, vegetation cover and total number of species were higher than on untreated plots. The application of fresh plant clippings from areas with similar habitat conditions appears to be a viable alternative to traditional restoration methods.     

Long-Term Effects of Biosolids on Revegetation of Disturbed Sagebrush Steppe in Northwestern Colorado

A study was conducted to evaluate the long‐term effects of biosolids amendment on restoration of disturbed sagebrush steppe habitat in northwestern Colorado. Twenty‐four years after biosolids amendment, soil fertility and plant community development were studied in replicated plots receiving various biosolids amendments on two different substrates. The two substrates used were a subsoil, determined to have low initial fertility, and a topsoil over retorted shale substrate, determined to have relatively high initial fertility. Results suggest that biosolids amendments have long‐lasting effects on soil fertility and plant community composition, but these effects vary between the two substrates that were utilized. Within the plots established on subsoil, the long‐term effect of biosolids was a reduction in plant species diversity and dominance by perennial grasses. On the topsoil substrate, there was a decrease in perennial grasses and an increase in shrub dominance with increasing biosolids. Results demonstrate the importance of considering initial soil conditions, seed mixture, and biosolids application rate when using biosolids for restoration of disturbed sagebrush steppe habitat. The long‐term effects of the biosolids treatments at this site demonstrate the need to consider restoration treatment effects over longer and more ecologically meaningful time frames.     

Seed dispersal by water: a contribution to the interpretation of seed assemblages

The composition of a seed flora always differs from actual vegetation. For archaeobotanists, who try to reconstruct former communities on the basis of plant macrofossils extracted from soil samples, this is a serious handicap. This difference can be explained by dispersal processes and by differences in preservation. Seeds that are incorporated into the soil may originate from both local and regional vegetation. Once incorporated, differences in preservation may result in a seed flora from a mixture of communities. The comparison may be further confounded when seeds that are transported over long distances are also of subfossil or even fossil origin. Both wind and water are effective agencies for long-distance dispersal. This study deals with the dispersal of botanical macro-remains by water. Water may be considered an important dispersal agent, especially in sites situated in the vicinity of running water, or liable to contact with water during storm surges or river floods. Therefore, the interpretation of seed assemblages from sediments that may have been in contact with running water needs special attention. In order to obtain information about the dispersal potential of plant remains by water transport, litter which had been transported by the river Rhine, and litter which had been washed ashore on the North Sea coast of the Netherlands was examined.     

Dissolved organic carbon production and runoff quality following peatland extraction and restoration

We examined dissolved organic carbon (DOC) production and quality in a cutover (extracted) and restored peatland in eastern Québec through a combined laboratory DOC production study and an accompanying field DOC runoff quality study. Both temperature and substrate were significant for explaining variability in net DOC production rate in both short (5 days) and longer term (25 day) laboratory incubations. Moss (Sphagnum spp. and Polytricum spp.) produced the least amount of DOC, with initial release rates of 0.02–0.35 mg DOC g⁻¹ d⁻¹. Shrubs, and to a lesser extent herbaceous vegetation, showed an initial high release of DOC followed by a decrease. Peat from the restored site had significantly higher longer-term DOC production rates than the cutover site. Humic acid (HA) was more likely to be produced by shrub and herbaceous plant material than by peat, mosses and straw. The hydrophilic (HPI) fraction of the DOC increased at higher temperatures. Despite differences in the surface cover of available substrate (e.g. vascular vegetation, moss, and straw), there was no difference in the quality of DOC exported from the cutover and restored sites. However, hydrological and biogeochemical controls were apparent in temporal variability of DOC quality in discharge. DOC exported during snowmelt and most storm events was high in HPI with little contribution from HA. Since contact time between water and soil is limited during these high flow periods, larger more hydrophobic HA molecules are less likely to be mobilized. Higher export of HA in summer compared to spring and autumn suggests that polycondensation and increased vascular plant productivity are important for controlling seasonal patterns of DOC export quality. As various substrates produced different amounts and quality of DOC, it is likely that the DOC quality exported from the restored site will continue to change as the new vegetation community develops. DOC production rates and DOC quality should be considered when developing a plan to control DOC runoff/export from managed peatlands.     

Investigation of artifacts from chronographic tethering experiments—interactions between tethers and predators

We used a submersible chronographic tethering device to compare the survival time of tethered juvenile brown tiger prawns (Penaeus esculentus [Haswell, 1897]) in seagrass and bare plots at two different sites. At one site, more prawns survived and those that were eaten survived for longer among the seagrass than on the bare habitat. However, at the other site there was little difference between numbers of survivors and survival time in the seagrass compared to the bare substrate. Laboratory observations suggest that the difference in survival was due to an effect of the tethers on the prawn's ability to escape from blue-swimmer crabs (Portunus pelagicus [Linnaeus 1758]), and differences in the abundance of P. pelagicus at the two field sites. P. pelagicus rely on olfaction, rather than sight to locate their prey, and so the crabs' efficiency at locating tethered prawns is not affected by the structure that seagrass provides. Our results clearly demonstrate an example of an artifact caused by experimental intervention, and highlight the need to investigate the possible effects of these types of artifacts.     

Ecosystem Services from Keystone Species: Diversionary Seeding and Seed‐Caching Desert Rodents Can Enhance Indian Ricegrass Seedling Establishment

Seeds of Indian ricegrass (Achnatherum hymenoides), a native bunchgrass common to sandy soils on arid western rangelands, are naturally dispersed by seed‐caching rodent species, particularly Dipodomys spp. (kangaroo rats). These animals cache large quantities of seeds when mature seeds are available on or beneath plants and recover most of their caches for consumption during the remainder of the year. Unrecovered seeds in caches account for the vast majority of Indian ricegrass seedling recruitment. We applied three different densities of white millet (Panicum miliaceum) seeds as “diversionary foods” to plots at three Great Basin study sites in an attempt to reduce rodents' over‐winter cache recovery so that more Indian ricegrass seeds would remain in soil seedbanks and potentially establish new seedlings. One year after diversionary seed application, a moderate level of Indian ricegrass seedling recruitment occurred at two of our study sites in western Nevada, although there was no recruitment at the third site in eastern California. At both Nevada sites, the number of Indian ricegrass seedlings sampled along transects was significantly greater on all plots treated with diversionary seeds than on non‐seeded control plots. However, the density of diversionary seeds applied to plots had a marginally non‐significant effect on seedling recruitment, and it was not correlated with recruitment patterns among plots. Results suggest that application of a diversionary seed type that is preferred by seed‐caching rodents provides a promising passive restoration strategy for target plant species that are dispersed by these rodents.