Seeds Of Native Plants Research Articles

Selection of Seeds of Common Native and Non-native Plants by Granivorous Rodents in the Northeastern United States

Abstract Post-dispersal seed predation by rodents represents a potentially important element of biotic resistance to plant invasion. Selection for five different types of seeds by granivorous rodents was studied in maple-beech forests, old fields and conifer plantations in Madison County, New York. Rodents visited dishes containing equal masses of seeds of the native Cornus amomum and Rubus idaeus, and the non-native Lonicera morrowii, Rhamnus cathartica and Rosa multiflora. Greater masses of C. amomum and R. idaeus seeds were consumed during a night of mammal visitation than of the three non-native species, and pattern of selection did not differ among habitats. Rodents encountered seed dishes sooner in forested habitats than old fields. The primary seed predators in our region, Peromyscus spp., were more common at forests and plantations than old fields. Patterns of habitat use by Peromyscus spp. may aid in resisting invasion of intact forests by invasive plants; however, selection of native over non-na...

Post-Wildland Fire Desertification: Can Rehabilitation Treatments Make a Difference?

Desertification, caused by land degradation as opposed to the immediate creation of classical deserts, is of prime concern in the 21st century. As a result of human activities and climate change, the land loses its proper hydrologic function and biological productivity. Desertification affects 33 % of the earth’s surface and over a billion people. Fire-related desertification has a number of environmental, social, and economic consequences. The two key environmental consequences are soil erosion and non-native plant invasions. Erosion after wildland fires can be in the range of <1 Mg ha−1 to 370 Mg ha−1, depending on fire severity, degree of water repellency, slope, and post-fire rainfall events. Soil losses in the high end of that range definitely exceed soil loss tolerances and contribute to desertification. Non-native plants are typically ten times as abundant on landscapes burned by wildland fires than on unburned lands. Seeding has been used for many years as a prime Burned Area Emergency Response (BAER) treatment. Until recently, this seeding contributed to non-native plant invasions because fast-growing but non native plant seeds were used. The use of native plant seeds and sterile hybrids has reduced this problem somewhat. However, even certified weed-free seed lots have low percentages of non-native plant seeds. Recent use of wet and dry mulches have contributed to reduced postwildland fire erosion rates, but they are quite expensive. This paper examines post-wildland fire desertification and the capabilities of BAER treatments to deal with this growing problem.

WEED‐BIOCONTROL INSECTS REDUCE NATIVE‐PLANT RECRUITMENT THROUGH SECOND‐ORDER APPARENT COMPETITION

Small-mammal seed predation is an important force structuring native-plant communities that may also influence exotic-plant invasions. In the intermountain West, deer mice (Peromyscus maniculatus) are prominent predators of native-plant seeds, but they avoid consuming seeds of certain widespread invasives like spotted knapweed (Centaurea maculosa). These mice also consume the biological-control insects Urophora spp. introduced to control C. maculosa, and this food resource substantially increases deer mouse populations. Thus, mice may play an important role in the invasion and management of C. maculosa through food-web interactions. We examined deer mouse seed predation and its effects on seedling emergence and establishment of a dominant native grass, Pseudoroegneria spicata, and forb, Balsamorhiza sagittata, in C. maculosa-invaded grasslands that were treated with herbicide to suppress C. maculosa or left untreated as controls. Deer mice readily took seeds of both native plants but removed 2-20 times more of the larger B. sagittata seeds than the smaller P. spicata seeds. Seed predation reduced emergence and establishment of both species but had greater impacts on B. sagittata. The intensity of seed predation corresponded with annual and seasonal changes in deer mouse abundance, suggesting that abundance largely determined mouse impacts on native-plant seeds. Accordingly, herbicide treatments that reduced mouse abundance by suppressing C. maculosa and its associated biocontrol food subsidies to mice also reduced seed predation and decreased the impact of deer mice on B. sagittata establishment. These results provide evidence that Urophora biocontrol agents may exacerbate the negative effects of C. maculosa on native plants through a form of second-order apparent competition-a biocontrol indirect effect that has not been previously documented. Herbicide suppressed C. maculosa and Urophora, reducing mouse populations and moderating seed predation on native plants, but the herbicide's direct negative effects on native forb seedlings overwhelmed the indirect positive effect of reducing deer mouse seed predation. By manipulating this four-level food chain, we illustrate that host-specific biological control agents may impact nontarget plant species through food-web interactions, and herbicides may influence management outcomes through indirect trophic interactions in addition to their direct effects on plants.

Does seed availability limit plant establishment during salt marsh restoration?

Patterns of seed dispersal and seed bank accumulation need to be known to predict the species that will recruit into restoration sites versus those that must be introduced. We assessed the temporal and spatial patterns of seed availability and seed accumulation on the salt marsh plain of an 8-ha resforation site, based on seedlings that emerged from tidal material, wrack, rabbit pellets, and soil samples (in controlled experiments). We compared results from the first 3 yr of restoration (2000–2002) with results from a 5-yr-old restoration and an extant marsh, all within Tijuana Estuary, California. Seed dispersal was limited for most marsh plain species. Tidal dispersal occurred mainly in winter; seedling density and richness were highest with high spring tides and after fruiting of the dominant species,Sarcocornia pacifica (>90% of emergent seedlings).S. pacifica was also common in the seedlings that emerged from soil seed banks (up to 63%) and wrack (60%), while other species common in the vegetation were present at much lower densities. Seed bank accumulation in restored sites was low and few species were abundant. Seedlings that emerged from soil samples from the youngest restoration were mostly invasive exotics (64%), those of the 5-yr restoration were mostlyS. pacifica (63%), and those from the nearby extant marsh were mostlyTriglochin concinna (70%), despite more diverse vegetation. No salt marsh seedlings emerged from rabbit pellets; all were invasives (Mesembryanthemum crystallimum andCarpobrotus edulis). Emerging seedlings were much sparser in soil from the younger restoration than from the 5-yr restoration and the extant site (32.9±5.7<4642.2±1131.5 and 4689.3±359.3 seedlings m−2, respectively). Because dispersal is limited for most species, restoring diverse vegetation will require seeding or planting. Natural recruitment could be facilitated by completing restoration by early winter, when seeds of native plants have maximum tidal dispersal.

Native Plant Regeneration on Abandoned Desert Farmland: Effects of Irrigation, Soil Preparation, and Amendments on Seedling Establishment

Abstract Direct seeding methods to revegetate abandoned farmland were tested at a desert site west of Phoenix, Arizona. Native seeds were broadcast onto plots prepared by mulching, imprinting, chiseling, and fertilizing with phosphorous in a split‐plot design. Each main plot was split into subplots that were not irrigated, irrigated with saline (3.25 dS/m) well water, or irrigated and hand weeded of Salsola iberica. Native seeds germinated poorly on all treatments, and three annual exotic weeds (Brassica nigra, S. iberica, and Schismus spp.) dominated the plots. None of the main plot treatments (mulching, imprinting, chiseling, or fertilizing) had a significant effect on seed germination or canopy cover. Irrigation increased plant cover on plots, but weeds dominated the cover (&lt;4% native species, up to 50% weeds). Near the end of the second growing season a seed bank study was conducted in the greenhouse. Undisturbed desert soil had relatively few weed seeds and more native plant seeds than the disturbed agricultural soil samples, which had few viable native seeds and were dominated by Schismus spp., B. nigra, and S. iberica. The results illustrate the difficulty of establishing native plants on abandoned desert farmland due to the dominance of weedy species, the presence of salts in the soil, and the lack of adequate soil moisture in the treatments without supplemental irrigation.

Do frugivorous birds assist rainforest succession in weed dominated oldfield regrowth of subtropical Australia?

Exotic plants often form the first woody vegetation that grows on abandoned farmland. If this vegetation attracts vertebrate frugivores which disperse the seeds of native plants, then native plants may recruit to such oldfield sites. However, there is debate about the extent to which exotic vegetation assists or suppresses the regeneration of native plants, and about its effects on faunal biodiversity. These issues were investigated in subtropical eastern Australia, where rainforests were cleared for agriculture in the 19th century, and where regrowth dominated by camphor laurel ( Cinnamomum camphora, an exotic, fleshy-fruited tree) has become common on former agricultural land. The study assessed the assemblages of frugivorous birds, and the recruitment of rainforest plants, at 24 patches of camphor laurel regrowth. The patches were used by nearly all frugivorous birds associated with subtropical rainforest. Many of these birds (16 of 34 species) are considered to have a medium to high potential to disperse the seeds of rainforest plants, and eight of these were abundant and widespread in regrowth patches. Of 208 recorded plant species, 181 were native to local rainforest. The ratio of native to exotic species was higher amongst tree recruits than adult trees, both for numbers of species and individuals. Among native tree recruits, 79% of 75 species, and 93% of 1928 individuals, were potentially dispersed by birds. These recruits included many late-successional species, and there were relatively more individuals of late-successional, bird-dispersed native species amongst recruits than adult trees. The species richness, but not the abundance, of both frugivorous birds and of bird-dispersed rainforest trees decreased with distance from major rainforest remnants. Camphor laurel regrowth provides habitat for rainforest birds and creates conditions suitable for the regeneration of native rainforest plants on abandoned farmland. Careful management of regrowth dominated by fleshy-fruited exotic invasive trees can provide an opportunity for broadscale reforestation in extensively-cleared landscapes.

SEEDS OBTAINED BY VACUUMING THE SOIL SURFACE AFTER FIRE COMPARED WITH SOIL SEEDBANK IN A FLATWOODS PLANT COMMUNITY

One method of obtaining seeds of native plants may be to let seeds fall to the soil surface and collect them by vacuuming. We evaluated this method by comparing plants that germinated from material vacuumed after fire with plants that germinated from seeds found in cores taken from the top 25 mm (1 in) of soil in a Florida flatwoods plant community before and after fire. A total of 76 species were identified in cores, of which 66 species were found before, and 60 species after, fire. No differences attributable to fire were found for seed density (3261 seeds/m² [2740/yd²]) or concentration in cores (282 seeds/kg [128/lb]). Vacuumed material contained seeds of 58 species (54 in common with cores) with a density of 170 seeds/m² [142/yd²] and a concentration of 451 seeds/kg (204/lb). Species correlations between cores and vacuumed material were significant for 19 of 46 species whose density was &gt; 1/m² in cores. Seeds of 10 species in vacuumed material were common as plants in standing vegetation, but seeds of 13 species (mostly shrubs) growing on the site were not in cores or vacuumed material. Vacuuming the soil surface may be effective for obtaining a diverse supply of seeds for herbaceous plants common on flatwoods after fire. Some species in vacuumed material, however, may not be in proportion to seeds in soil and the vacuumed material will not include seeds of some shrubs that characterize Florida flatwoods communities.

Cordless Hedge Trimmer for Seed Collection

We use a rechargeable hedge trimmer to collect seeds of native plants. With an easy modification and an inverter that plugs into a vehicle cigarette lighter, the trimmer is ready to harvest seeds as we travel about.

Seed quality and New Zealand's native plants: An unexplored relationship?

Seed quality refers to a number of seed properties which may have varying degrees of practical importance depending on species and end use. Possible reasons for requiring information about the quality of seeds of New Zealand's native plants are presented, and data for both seed physical and physiological quality reviewed. Despite the strategic value of New Zealand's native plants in biological diversity and for the conservation of this biodiversity, their seed quality is largely an unknown area of plant science.

Persistence in the seed bank: The effects of fungi and invertebrates on seeds of native and exotic plants

Fungal pathogens and invertebrate seed predators both may limit the establishment of persistent seed banks. Exotic plants may be less subject to attack by these natural enemies than are native species; if so, this may provide exotics with an important advantage by reducing seed mortality and enhancing the persistence of colonizing populations. We investigated this idea with a field experiment in which we used fungicides and screening to protect seeds of 39 native and exotic old field plants. The recovery of germinable seeds was improved by fungicide additions, but not by the exclusion of macroinvertebrates. The effects of fungicide varied among species and sampling dates, but the recovery of natives was not consistently improved more than the recovery of exotics. These results suggest that soil fungi have important impacts on the seed banks of many species, but that exotics are not consistently more resistant than natives to attacks by either fungal pathogens or invertebrates. Consequently, it is unlikely that the majority of invaders benefit from reduced pest loads at the seed bank stage.

Effects of fungal pathogens on seeds of native and exotic plants: a test using congeneric pairs

SummaryIt has previously been hypothesized that low rates of attack by natural enemies may contribute to the invasiveness of exotic plants.We tested this hypothesis by investigating the influence of pathogens on survival during a critical life‐history stage: the seed bank. We used fungicide treatments to estimate the impacts of soil fungi on buried seeds of a taxonomically broad suite of congeneric natives and exotics, in both upland and wetland meadows.Seeds of both natives and exotics were recovered at lower rates in wetlands than in uplands. Fungicide addition reduced this difference by improving recovery in wetlands, indicating that the lower recovery was largely attributable to a higher level of fungal mortality. This suggests that fungal pathogens may contribute to the exclusion of upland species from wetlands.The effects of fungicide on the recovery of buried seeds did not differ between natives and exotics. Seeds of exotics were recovered at a higher rate than seeds of natives in uplands, but this effect was not attributable to fungal pathogens.Fungal seed pathogens may offer poor prospects for the management of most exotic species. The lack of consistent differences in the responses of natives vs. exotics to fungicide suggests few aliens owe their success to low seed pathogen loads, while impacts of seed‐pathogenic biocontrol agents on non‐target species would be frequent.

Antifungal proteins from seeds of Australian native plants and isolation of an antifungal peptide from Atriplex nummularia

Extracts from seeds of 69 different species of plants mostly originating from Australia were screened for antifungal agents with activity against the plant pathogens, Fusarium oxysporum fsp. vasinfectum, Rhizoctonia solani, Thielaviopsis basicola, and Verticillium dahliae. Many seed extracts showed inhibitory activity against one or more of the fungi tested. High antifimgal activities were detected in the genera Archontophoenix, Atriplex, Alphitonia, Callistemon, and Dodonaea. Only the Atriplex seed extract was shown to contain a protease-sensitive antifungal activity. A 30 amino acid residue peptide (An1) was purified to homogeneity from the seeds of Atriplex nummularia and its in vitro activity against several fungal pathogens of plants was characterised. Amino acid sequence analysis revealed Anl to be homologous to the chitin-binding antimicrobial peptides of Amaranthus caudatus.

The seed rain and seed bank of an adjacent native tallgrass prairie and old field

The ability of a grassland to regenerate following disturbance depends on the presence of seeds of native plants and the ability of the seeds to germinate. To examine whether the presence or absence of plant propagules influences reestablishment of tallgrass prairie on abandoned agricultural lands, we sampled the seed rain and soil seed bank across a transition from native tallgrass prairie to unmanaged successional grassland (old field). The native prairie seed rain was seven times greater than that of the old field, richer in species (33 vs. 27), and more diverse (diversity index 0.96 vs. 0.73). In addition, the native tallgrass prairie seed bank was three times as dense as the old-field seed bank and contained the seeds of more species (23 vs. 19), but had a lower index than did the old field (0.81 vs. 1.08). One species, Sphenopholis obtusata, present in the prairie, was observed dispersing to the old-field plot, but was absent in the old-field plot; this observation suggests that at least some species are unable to establish on the old-field plot. Thus, the ability of a native grassland to reestablish may be limited by the dispersal ability of native species and the ability to establish once dispersed. Key words: seed rain, seed bank, native tallgrass prairie, old-field succession.

Insect predation of seeds of native New Zealand woody plants in some central South Island localities

Abstract Samples of fruit collected from woody plants in central South Island lowland forests, showed that nine species were more or less heavily affected by insect seed predation (more than 10% of seeds and up to 63% eaten in some samples). One obligate seed-eater each occurred in seven of these; the rest had two or more. Two were also attacked by facultative seed-eaters. A further eight species of plants were affected to a lesser degree by obligate or facultative seed-eating insects. Moth larvae from nine families and ten genera are the main seed eaters, but weevils are important for some plant species.

Native Seed Collection, Processing, and Storage for Revegetation Projects in the Western United States

AbstractThe foundation of a successful revegetation or restoration program is quality native seed. This requires careful collection, processing, and storage. Mature seed should be collected from healthy, local stands with a sufficiently broad genetic base. Careful identification of the site characteristics and seed‐lot tracking are essential. Yearly variation in seed production and seed quality can be very high, and an early determination of seed quality can prevent expensive failures. Nondestructive evaluation using X‐rays is effective and economical, but techniques such as staining, inspection, and germination tests can also be helpful. Cleaning, dewinging, and upgrading seed before storage can (1) reduce weight and bulk, (2) improve storage life, (3) increase germination, and (4) make greenhouse production and field planting easier and more economical. The seeds of many native plants can lose their viability quickly if they are not stored under controlled conditions. Seeds in storage must also be protected from rodents, pests, and disease. Dormancy is common in the seeds of many native species, and experimentation is often necessary to determine the best way to break seed dormancy. This can be complicated by year‐to‐year and plant‐to‐plant variation.

Stimulation of Germination of Quandong (Santalum acuminatum) and Other Australian Native Plant Seeds

Intact seeds of quandong (Santalum acuminatum), Ixodia achillaeoides, Ptilotus exaltatus, Codonocaupus pyramidalis and Exocarpos aphyllus which are normally difficult to germinate responded to vacuum infiltration with gibberellins. In most cases GA4 was far more effective than GA3. Cytokinins, ethylene and silver ions did not affect quandong germination but abscisic acid (ABA) was inhibitory. If imbibed quandong seeds were subject to a rapid drying and re-wetting cycle, subsequent germination was inhibited. This transient drying was associated with a rise in endogenous ABA and the effect of the drying could be overcome by gibberellin. There was no correlation between ABA level and state of dormancy in recently imbibed seed suggesting that ABA was not necessary for the maintenance of dormancy. These results suggest that the mechanisms controlling quandong seed germination are hormonally based although the mechanical constraints imposed by the rigid shell may also be important.

Silica and Ash in Seeds of Cultivated Grains and Native Plants

Silica and ash contents and the depositional patterns of opaline silica have been determined in the seeds of 31 plant species. Included were 13 monocotyledons, eight dicotyledons and the seeds of eight common cereal grains

Quality and storage characteristics of the seeds of important native pasture species in South-West Queensland.

Seeds of native plants can be difficult to germinate reliably. In addition, the useful life of a carefully harvested seed lot needs to be known. This paper reports on the laboratory germination over eight years of seed of 27 native pasture species hand-harvested near Charleville after the 1972-73 summer and stored in a laboratory without special conditions. The legumes had prolonged hard-seededness and high viability. Forb species varied in their degree of hard-seededness and the level of initial dormancy, Most perennial grasses produced high quality seed which attained best germination between one and three years after harvest. The Andropogoneae had much poorer seed fill than most other species. Laboratory germination of annual and small seeded grasses was often low, even after scarification. Thus, the use of freshly harvested or old, untested seed of native rangeland species in - research programmes is very unwise.

Winter Condition of Mallards on the Southern High Plains of Texas

Body composition and condition of mallards (Anas platyrhynchos) wintering on the Southern High Plains (SHP) of Texas were studied from October to March 1979-82. Lipid reserves, and usually body weights, of all sex and age classes were lowest in autumn. By mid-winter, however, lipid reserves increased 49-62% for adults and 21-30% for juveniles and averaged 13-18% of body weight. The majority of these reserves (56-100%) were acquired from autumn to early winter. Adults and juvenile females then lost lipids from mid-winter to late winter (9-15%), but juvenile males increased reserves by 20%. Adult females mobilized more lipids than adult males during late winter (15 vs. 9%) and previously had acquired a larger reserve (20 vs. 7%). Body weight and lipids increased before spring migration. Overall, mallards on the SHP maintained better condition than those wintering farther north. J. WILDL. MANAGE. 50(1):52-57 Body weight and carcass composition of waterfowl are not stable during winter (Peterson and Ellarson 1979, Raveling 1979, Reinecke et al. 1982). These changes may be influenced by body condition, which has been defined as an individual's ability to meet present and future needs (Owen and Cook 1977). In this paper we refer to condition as the relationship between an individual's endogenous energy reserves and energy demands for maintenance, productivity, and activity. The SHP of Texas is an agricultural region where wintering mallards have adopted a fieldfeeding strategy; they join northern pintails (A. acuta), American wigeons (A. americana), and green-winged teal (A. crecca) in morning and evening field-feeding flights for waste corn (Baldassarre and Bolen 1984). More than 90% of the diet, by volume, consisted of corn during a 2-year study sampling 324 mallard crops and gizzards (Moore 1980). Corn is higher in energy than seeds of native plants occurring in the numerous playa lakes that serve as wetland habitat for waterfowl on the SHP (Baldassarre et al. 1983). This high energy content influences body condition as available carbohydrates are converted into endogenous lipids (Hazelwood 1976). Lipids, in turn, become important reserves used by birds during periods of winter stress (Blem 1976). However, although mallards wintering on the SHP have access to high energy foods, they also encounter temperature stress during certain periods (Whyte and Bolen 1984). The objective of this study was to determine the relationship between winter stress and carcass composition, especially lipid reserves, of mallards wintering on the SHP. Financial support was provided by the Caesar Kleberg Found. Wildl. Conserv. and the U.S. For. Serv. (F. A. Stormer, Proj. Leader, Great Plains Wildl. Habitat Res. Lab.). J. D. Myrick, J. R. Davis, C. L. Lee, H. A. McLain, D. W. Brown, W. J. Hill, and T. J. Hill granted access to private property. R. J. Baker, K. T. Scribner, J. J. Juen, E. E. Quinlan, G. E. Huber, R. H. Lunn, and R. D. Godfrey aided collection of mallards during hunting seasons. R. D. Godfrey, J. A. Templer, and J. J. Peterson assisted with laboratory work. L. J. Celentano and D. B. Webster provided advice during statistical and computer analysis of the data. We are grateful to all. This is contribution T-9-370 of the Coll. Agric. Sci., Texas Tech Univ., Lubbock.

Study of Viable Seeds in Various Habitats in Mixed Prairie

In the Great Plains it is important that denuded or partially denuded areas be covered with vegetation as soon as possible; otherwise erosion and consequent soil deterioration are likely to become severe. Areas varying in size from a few square feet to many acres are often destroyed by grazing, trampling, drought, and other means. For example, the drought of 1933-40 caused considerable damage to the grasses, but where they were also overgrazed, reduction in cover was much more severe (Weaver & Albertson 1944). Whatever the cause, new populations must come either through migration or from seeds or plants remaining in the area. Seeds of many native plants may lie dormant for several years and then germinate when environmental conditions become favorable. However, this supply of dormant seeds may become exhausted if proper growing conditions do not follow germination at least part of the time (Weaver & Mueller 1942). The purpose of this study was to ascertain what viable seeds were present in the surface soil of various plant communities in the mixed prairie association several years after the drought. These data furnish some information as to what plants might be expected to populate the areas if the vegetation were destroyed.