Ammophila Breviligulata Research Articles

Facilitative effects of a sand dune shrub on species growing beneath the shrub canopy.

Only recently has the importance of positive interactions among plant species in structuring natural communities been supported by experimental evidence. Most studies have focused on interactions between a pair of species at a single life-history stage. In this study positive interactions between a woody nitrogen-fixing shrub (Myrica pensylvanica) and two herbaceous sand dune species (Solidago sempervirens, Ammophila breviligulata) which frequently grow beneath shrub canopies are examined throughout the life cycles of the herbaceous species. Comparisons of S. sempervirens and A. breviligulata growing beneath and outside M. pensylvanica shrubs show that plants growing in association with shrubs are larger, are more likely to flower, produce greater numbers of flowers and seeds, have higher midday xylem water potentials, have higher tissue nitrogen concentrations, and have higher photosynthetic efficiencies. Measurements of environmental conditions show that areas beneath shrubs are more shaded, have lower soil temperatures, and have higher soil nitrogen levels. The results from experimental manipulations designed to test the effects of Myrica shrubs on understory species suggest that the observed differences in plant performance are strongly influenced by canopy shading and soil nutrient enrichment associated with the shrubs. The results demonstrate that M. pensylvanica facilitates growth, reproduction, and recruitment of S. sempervirens and A. breviligulata growing beneath it. This study, one of the few to examine positive interactions at different life-history stages, supports previous predictions that positive interactions may be particularly important in plant communities characterized by physiologically stressful conditions.

The role of ethylene and darkness in accelerated shoot elongation of Ammophila breviligulata upon sand burial.

The impact of elevated ethylene concentrations and darkness on the growth and development of shoot organs of Ammophila breviligulata was investigated under experimental conditions in a complete two-way design. The results were compared with data of partially sand buried plants. Enhanced ethylene concentrations and sand burial stimulated the formation of new stem nodes, a prerequisite for burial-induced shoot elongation. However, internode elongation itself could not be promoted by the phytohormone ethylene, by darkness, or by their interaction. Sand burial inhibited the formation of rhizomes and tillers and the investment in root and rhizome biomass. Darkness mimicked this effect for the number of rhizomes and the biomass allocated to roots and rhizomes, indicating that the change in light regime upon sand burial may play an important role in the signal transduction chain that leads to a different allocation pattern in A. breviligulata. The results are discussed within the context of alternative signals that might initiate the internode elongation response in sand-buried A. breviligulata plants.

Vegetation of a Freshwater Dune Barrier Under High and Low Recreational Uses

BONANNO, S. E., D. J. LEOPOLD, AND L. R. ST. HILAIRE. Vegetation of a freshwater dune barrier under high and low recreational uses. J. Torrey Bot. Soc. 125:40-50. 1998.-The 27.4 km freshwater dune barrier on the eastern shore of Lake Ontario protects an extensive system of high quality wetlands. The vegetation was previously undescribed, and development pressures required management decisions for which data were needed. The objective of this study was to describe and compare the vegetation under high and low recreational use. We found four community types using hierarchical classification (TWINSPAN): (1) Ammophila breviligulata (beachgrass) (2) Toxicodendron radicans-Vitis riparia-Populus deltoides (brushland) (3) Quercus rubra-Acer rubrum (forest), and (4) Alnus incana (thicket). Reciprocal averaging ordination displayed communities along a first gradient of distance from the beach. A second gradient is likely related to disturbance. Species composition was similar in beachgrass and brushland communities under high and low recreational use. Under low use, forest and shrub thicket were present on the back of the barrier, but were absent under high use. Species richness and ground cover of vegetation, and density of colonizing species were lower on equivalent physiographic zones under high compared to low recreational use.

Foredune development on Îles de la Madeleine (Quebec), Atlantic Canada

The foredune, in this cool-temperate, sediment-abundant, relatively high wind and wave energy environment, is generally a single ridge with a mean height of 5.1 m (max. 11.4 m) and width of 25–35 m. Pioneer vegetation is dominated by Ammophila breviligulata. Four foredune types were identified: scarped, scarped with blowouts, scarped with incipient foredune, and nonscarped, the first being the most common, occupying more than 50% of the shoreline. Foredune erosion and retreat is occurring at an average rate of 0.8 m∙a−1. The marked differences in dune character between the west and east coasts of the islands are related to differences in wave energy and shoreline dissipativeness. The higher energy west coast exhibits more dynamic dunes with more frequent blowouts, which may develop into parabolic forms.

Aboveground Biomass and Net Primary Production along a Virginia Barrier Island Dune Chronosequence

-Aboveground biomass was measured along a chronosequence of dunes on Hog Island, a Virginia Coast Reserve LTER site. The dominant species were Ammophila breviligulata and Spartina patens. Aboveground biomass was harvested monthly from 10 quadrats on 6, 24, 36 and 120-yr-old dunes from April to November 1993. Total aboveground biomass decreased along the chronosequence and ranged from 205 g m-2 on the 6-year-old dune to 152 g m-2 on the 120-yr-old dune in October 1993. Spartina patens biomass exceeded A. breviligulata biomass on the 6, 24 and 36 yr-old-dunes. Spartina patens biomass decreased along the chronosequence; in July it ranged from 72 g m-2 on the 6-yr-old dune to 5 g m-2 on the 120-yr-old dune. Ammophila breviligulata biomass increased from 17 g m-2 on the 6-yr-old dune to 39 g m-2 on the 120-yr-old dune. Ammophila breviligulata had greater biomass than S. patens on only the 120-yr-old dune. Net aboveground primary productivity did not vary along the chronosequence. Aboveground net primary production (ANPP) from the sum of species peaks was 259 g m-2 yr-1 for the 6-yr-old dune, 226 g m-2 yr-1 for the 24-yrold dune, 256 g m-2 yr-1 for the 36yr-old dune and 274 g m-2 yr-1 for the 120-yr-old dune. There was no opportunity to study dunes of the same or comparable ages on other barrier islands, so these inferences apply only to the four dunes studied on Hog Island.

Mycorrhizae and succession in plantings of beachgrass in sand dunes

A survey of arbuscular mycorrhizal fungi (AMF), arbuscular mycorrhizae (AM), and hyphal networks of AMF was carried out in sand dune sites of different successional stages in the Province Lands Area of Cape Cod National Seashore, Massachusetts. The study focused on large‐scale plantings (each of 12–20 ha) of American beachgrass (Ammophila breviligulata) aged 0–7 yr and five adjacent natural dune areas. Sample sites ranged in vegetative cover from barren to forested. Spores of 17 species of AMF were recovered from the dunes. Over the successional sequence, there were increases in the richness and spore populations of the AMF community, the extent of colonization of A. breviligulata roots, and the mycorrhizal inoculum potential of the soil. Unvegetated sites lacked propagules of AMF, but roots of planted culms of A. breviligulata (which carried propagules of AMF) became mycorrhizal in <1 yr after planting. Spores were recovered from previously AMF‐free sites that had been planted with beachgrass for 47 wk, and five species of AMF sporulated in sites <6 yr old. Significant hyphal networks were not present in any of the planted areas (<6 yr old at the time of sampling), but did occur in natural areas. The rate of invasion of areas planted to A. breviligulata by later successional plant species may in part depend upon the establishment of a vigorous network of hyphae of AMF in a site.

Relationships among plant-parasitic nematodes, mycorrhizal fungi and the dominant vegetation of a sand dune system

:We investigated the influence of arbuscular mycorrhizal (AM) fungi and plant-parasitic nematodes on the composition of dominant grasses in a lacustrine sand dune habitat. The data were subjected to canonical correlation analysis to determine the relationships within and between plant species and the soil variables. The plant species displayed a zonal distribution across the study area but colonization of these species by AM fungi was relatively constant. Plant-parasitic nematodes of the genus Meloidogyne were the most abundant of all nematode genera in the study area. They were also more frequent in the high beach zone (dominated by the beachgrass Ammophila breviligulata) as compared to other zones. The richness of endoparasitic nematode genera was correlated with a decline in density of Ammophila breviligulata and an increase of Andropogon scoparius, with increasing distance inland from the beach. Inferring causal relations by simple observation may not be possible because of the complexity of soil environment.

Population ecology ofCirsium pitcherion Lake Huron sand dunes: II. Survivorship of plants

Cirsium pitcheri is a threatened plant species endemic to the shoreline sand dunes of the Greak Lakes. In this study, we attempted to identify some of the environmental factors that may limit the growth, survival, and reproduction of its populations. This species occurs as a minor associate among mixed populations of three dominant grass species, Ammophila breviligulata, Calamovilfa longifolia, and Andropogon scoparius in sandy soil of varying texture (fine, medium, coarse, or shingle). It occupies bare areas within stands of grasses on the first and second sand dune ridges and is prevalent in blowouts. The size class distribution based on the number of leaves per plant showed that the population was dominated by young plants (1–5 leaves) and the relative frequency of juveniles in each successive size class decreased from the smallest to the largest size class. Large juveniles were few in number, which suggests that there was high mortality during the juvenile phase. Seedling mortality in individual plots ranged from 11 to 90% in 1993 and 0 to 70% in 1994. Seed production of its populations was severely reduced because of consumption of whole capitula by white-tailed deer. Transition probabilities indicated that the probability of flowering was dependent on the size of the plant based on the longest leaf length. Keywords: survivorship, deer grazing, transition probability, sand texture, Cirsium pitcheri.

The `Ammophila Problem' Revisited: A Role for Mycorrhizal Fungi

1 A glasshouse study was conducted to determine the effects of three variables (sand burial, arbuscular mycorrhizal (AM) fungi and endoparasitic root nematodes) and their interactions on the growth of Ammophila breviligulata Fern. seedlings. We tested the hypotheses that burial allows A. breviligulata to escape from plant-parasitic nematodes and that inoculation with AM fungi is another factor capable of ameliorating the detrimental effects of nematodes to the plant. 2 Seedlings were grown in y-irradiated, sterile sand and treated in a factorial manner with 5 cm of sand burial, i'hizosphere inoculation with AM fungi and rhizosphere inoculation with plant parasitic nematodes. Both AM fungi and nematodes originated from field populations of A. breviligulata. 3 Burial stimulated the foliar growth rate of plants in all combinations except when plants had been infected with nematodes prior to burial. The root dry weight was significantly reduced when nematode infected plants were buried. AM fungi improved the foliar growth rate and root dry weight of buried plants infected with nematodes. We therefore rejected the hypothesis that burial allows escape from plant-parasitic nematodes. 4 AM fungi are capable of reducing plant susceptibility to plant-parasitic nematodes and must be considered when assessing the influence of plant-parasites on the vigour of natural A. breviligulata populations.

The effect of gap dynamics on the size and spatial structure of Solidago sempervirens on primary coastal dunes

Abstract. The role of gap dynamics in shaping the spatial and size distributions of the gap specialist Solidago sempervirens (seaside goldenrod) were examined on the primary dune grassland (Ammophila breviligulata, American beachgrass) of an Atlantic barrier island. Results suggest that coastal dune blowouts are patchy disturbances that allow S. sempervirens to temporarily establish and disperse seed. Natural measurements and clipping experiments demonstrated that A. breviligulata competitively dominated S. sempervirens in undisturbed grasslands. Coastal dune blow‐outs reversed this dominance by temporarily burying A. breviligulata and increasing densities and above‐ground biomass of S. sempervirens. Examination of size/density distributions of S. sempervirens suggested that blow‐outs were seed sources but not regeneration sites. Regeneration was found primarily in neighboring transition and undisturbed grassland areas. Comparison of lateral growth by A. breviligulata on blow‐out margins suggested that disturbances were closed by lateral encroachment from gap edges. After blow‐out recovery, greater densities and skewed size distributions of S. sempervirens could still be detected for a number of years after blow‐out recovery.

Coastal Dune Restoration: A Strategy for Alleviating Dieout of Ammophila breviligulata

AbstractDieout of Ammophila breviligulata— death of the major dune‐stabilizing plants — has been observed along the north and mid‐Atlantic coast of the United States for the past decade and a half. Pathogenic nematodes have been identified as the probable causal agents; they can bring about a complete dieout of sand dune vegetation, with Ammophila breviligulata being the first species to die. Typically, such an area would remain barren for up to five years before plants could be successfully introduced. Applications of fertilizer and dolomitic limestone were tested in the field as a possible management strategy to alleviate the vulnerability of a denuded dune to erosion by making it possible to plant such a site earlier than usual. These applications were also tested in an area of weakened and dying plants to determine if the vegetation could be saved before complete dieout occurred. By creating soil conditions conducive to vigorous plant growth, it was hypothesized that the plants could better withstand the stress of nematode attack. The addition of N‐P‐K macronutrient fertilizer resulted in increased growth and spread of plants introduced into a site where the grass had been dead for only one to two years. Results indicate that application of fertilizer would be necessary only every other year at most. Micronutrient application, at the concentration used in this study, had little or a somewhat detrimental effect. The addition of dolomitic limestone increased the survival of newly introduced plants. It was also found that the application of macronutrients to a site of moribund vegetation could not only rescue the plants in that site, but could also increase their growth, vigor, and spread, thereby preventing further loss of plant cover essential to dune stabilization.

The effect of accelerated sand accretion on growth, carbohydrate reserves, and ethylene production in Ammophila breviligulata (Poaceae)

In a 3‐yr field study Ammophila breviligulata responded positively to sand accretion by maintaining plant height above a rising sand surface. Vertical growth for treated plants was approximately 80 cm over 3 yr. Bunch size did not differ between treated and control plants in the first or second year. But by Year 3, bunch circumference, number of stems per bunch, and plant height above the sand surface were significantly greater in plants receiving accelerated sand accretion. During the first year, treated plants flowered significantly less than controls. The greater vertical growth necessary for the treated plants may have depleted the energy reserves of a young rhizome system otherwise used for inflorescence production. The percent of the total nonstructural carbohydrates in rhizomes in the form of sugar was greater in plants in the accelerated sand accretion treatment, perhaps sustaining the necessary rapid vertical growth. To determine whether ethylene plays a role in stimulating stem elongation, endogenous ethylene accumulation was measured in plants in the field and seedlings in the greenhouse exposed to sand accretion. Treated plants responded by accumulating higher levels of ethylene in their stems, after 10 and/or 30 d, than did control plants. However, plants treated with exogenous ethylene exhibited growth and elongation inhibition.

Effects of Sand Accretion on photosynthesis, Leaf-Water Potential and Morphology of Two Dune Grasses

Field studies were conducted to determine the effects of burial in sand on net CO 2 uptake, water potential and leaf morphology of two grasses, the C 3 , Ammophila breviligulata and the C 4 , Calamovilfa longifolia. Buried plants of both species exhibited higher net photosynthetic rates than controls. However, the increase in net CO 2 uptake was much greater in A. breviligulata than in C. longifolia. At the same burial depth, C. longifolia usually maintained a greater net photosynthetic rate than A. breviligulata. Sand accretion did not influence the water potential of leaves but resulted in a slight increase (not significant) in leaf thickness of A. breviligulata but a significant increase in leaf thickness of C. longifolia (...)

The effect of seed dispersal limitations on the spatial distribution of a gap species, seaside goldenrod (Solidago sempervirens)

This study examined the seed ecology of seaside goldenrod, Solidago sempervirens L., a gap species, on coastal dunes dominated by American beachgrass, Ammophila breviligulata. A test was done to determine whether lower densities of S. sempervirens on undisturbed primary dune grasslands were due to limited seed dispersal or barriers to seedling establishment. Seed rain was greater within blowouts and transition areas than in immature and mature grasslands. Blowouts and transition areas produced prominent seed shadows and served as primary seed sources. Both seed shadow measurements and inflorescence removal experiments suggested that the majority of seeds fell to the ground within 10 m outside blowouts. Experiments involving the hand broadcasting of seeds increased densities of seedlings in undisturbed areas. Plots with hand-drilled seeds showed no differences in percent emergence between transition and undisturbed areas; however, both were significantly greater than blowouts. Persistent seed storage in the soil was probably negligible. Seed bank densities at 5 m depth did not accurately reflect temporal or spatial patterns of seed rain. Often very low densities or no seeds were found in collected samples within an area. Furthermore, emergence percentages of field-buried seeds showed a significant drop-off after a single year. Thus, this study concluded that lower densities of plants in undisturbed areas were, in part, due to lack of seed dispersal from blowouts. Key words: seed dispersal, gap species, patchy disturbances, dune ecology, grassland ecology.

Response of Ammophila breviligulata to acid rain and low soil pH

The effects of simulated acid rain and low soil pH on the growth of Ammophila breviligulata (Cape Strain), American beach grass, were studied in greenhouse experiments. Plants treated with acid rain were shorter, but shoot density, live shoot biomass, and rhizome biomass were not adversely affected by the acid rain treatments. Root biomass was greatest in the acid rain treatments. A manipulated soil pH of 4.0, typical of that found in field sites of dying beach grass, resulted in significantly reduced plant height, shoot density, shoot biomass, and rhizome biomass. Root biomass was greater in the low pH treatment and was six times greater than rhizome biomass in that treatment while the root to rhizome ratio was approximately 1∶1 in the control — likely a reflection of the plant's response to decreased nutrient availability in the low pH soil. Acid rain treatment of dune sand resulted in the leaching of Al, a potentially phytotoxic element.

ENDOPHYTE‐HOST ASSOCIATIONS IN GRASSES. XVI. PATTERNS OF ENDOPHYTE DISTRIBUTION IN SPECIES OF THE TRIBE AGROSTIDEAE

Distribution of Acremonium endophytes in several species of Agrostideae is determined through surveys conducted in the field and in grass herbaria. Widespread geographic distribution of Acremonium in a particular grass species may indicate early colonization of the grass as a host, while a narrow pattern of geographic distribution suggests more recent colonization of the grass. Two grasses that appear to show a narrow endophyte distribution include Agrostis alba and Ammophila breviligulata. Cultural features of endophytes from several grasses are compared. A new variety of Acremonium typhinum is proposed to accommodate the endophyte from A. breviligulata. An endophyte in Agrostis alba is identified as Acremonium starrii. It is also suggested that Acremonium endophytes are spreading in grasses and may be progressively colonizing new hosts.

The spatial dispersion of spores of vesicular-arbuscular mycorrhizal fungi in a sand dune: microscale patterns associated with the root architecture of American beachgrass

In order to develop a model of the spatial dispersion of populations of vesicular-arbuscular mycorrhizal fungal (VAMF) spores within a root zone, we hypothesized that their spatial pattern would be correlated with the below-ground architecture (growth and structure) of the root system. Detailed excavation and mapping of the roots within the vicinity of three clusters of Ammophila breviligulata ramets (culms) revealed a network of rhizomes, many of which were not connected to the original plant. The species richness of VAMF for the three plots ranged from six to nine, including five genera. A high degree of spore clumping was not significantly correlated with the location of roots, nor with any of the physical soil parameters tested, or with the abundance of spores in adjacent sampling areas. The abundance of spores at a particular location in the soil generally was not a good predictor of spore populations only 10 cm distant. Since such spores are not readily dispersed from the point of sporulation, it is likely that some spore aggregations formed previously in association with fibrous roots that have subsequently decayed and are no longer detectable in the soil profile.

Population biology of Ammophila breviligulata and Calamovilfa longifolia on Lake Huron sand dunes. III. Dynamic changes in plant community structure

Changes in vegetation and physiography of Lake Huron shoreline were studied by recording total counts and by comparing photographs taken in 1977, 1985, and 1987. In 1977, a large number of annual and biennial plant species such as Cakile edentula, Corispermum hyssopifolium, Salsola kali, Euphorbia polygonifolia, Artemisia campestris, and Oenothera biennis were found growing in association with two perennial grasses, Calamovilfa longifolia and Andropogon scoparius. Ammophila breviligulata was absent at that time, but became abundant through establishment of ramets from rhizome fragments after the storms of 1979 and 1981. Two damaging storms, one in October 1986 and the second in April 1987, wiped out almost all of Ammophila breviligulata, leaving a few remnant shoots among clumps of Calamovilfa longifolia. Observations suggest that the low density (two shoots∙m−2) of Ammophila breviligulata tillers among Calamovilfa longifolia populations on the first dune ridge has resulted from landward extensions of plagiotropic rhizomes from the once abundant Ammophila breviligulata populations on the lakeward end of the beach.

The effects of experimental spills of natural gas condensate on three plant communities on Sable Island, Nova Scotia, Canada

We examined the effects of an experimental oiling with natural gas condensate on three plant communities on Sable Island, a sandy, temperate island located 160 km east of Nova Scotia in the Atlantic Ocean. The plant communities were: (i) a dune grassland dominated by Ammophila breviligulata; (ii) a herbaceous beach community dominated by Honckenya peploides; and (iii) a heath dominated by Empetrum nigrum, Myrica pensylvanica, Rosa virginiana, and Vaccinium angustifolium. The experimental treatments were: (i) control; (ii) sprayed with 6·3 litres of condensate/25 m 2 and (iii) sprayed with 12·5 litres/25 m 2. Initially, in all three communities there was a severe herbicidal effect on most above-ground plant tissues that were directly impacted by the condensate. However, below-ground perennating tissues were little affected by the hydrocarbon treatment, and the vigorous regeneration that issued from these tissues allowed an essentially complete recovery of most species after one or two post-spill growing seasons.

Vesicular-Arbuscular Mycorrhizal Fungi of Wisconsin Sandy Soils

Soils of the Great Lakes states are largely unexamined for vesicular-arbuscular mycorrhizal fungi (VAMF). Wisconsin, in particular, has no records of these fungi. There are only three reports (Koske, 1985; Koske et al., 1975, 1986) of VAMF being isolated from the great lacustrine dunes of North America, even though there are numerous reports of VAMF from North American maritime dune systems (e.g., for New England, Koske and Halvorson, 1981; Tews and Koske, 1986; and for the Northwest, Gerdeman and Trappe, 1974). The purpose of this study was to determine the species of VAMF present in dune soils of Lake Michigan and in sandy soils in Wisconsin and to compare the species lists with those of other dune systems. VAM fungi were collected from soil around the root zones of plants at 53 different sites. (FIG. 1 indicates the major collection sites.) The sites included dunes of Lake Michigan and Lake Superior, sandbars and banks of the Wisconsin River, and irrigated and unirrigated sandy soils of central Wisconsin. Samples (ca. 11) were collected from the following plants: Ammophila breviligulata Fern., Oct., 1983, July, 1984, June, 1985; Agropyron dasystachum (Hook.) Scrbn., July, 1984; Avena sp., June, 1985; Calamovilfa longifolia (Hook.) Scrbn., Oct., 1983, July, 1984; Glycine max L., July, 1985; Lathyrus maritimus (L.) Bigelow, Oct., 1983; Lythrum salicaria L., June, 1985; Poa praetensis L., July, 1984, June, 1985; Rosa sp., Oct., 1983; Zea mays L., June, 1985; sedges, June, 1985. Collection localities for each species are found in TABLE I. Soil samples were placed in plastic bags and stored at about 6 C until processed. Field observations regarding position, date, vegetational cover, and depth were recorded. Routinely, 2-3 root zones of each plant species were sampled at each site at a depth of 10-30 cm.