bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors Affecting Seed Germination and Seedling Establishment of Fen‐Meadow Species
Authors: Isselstein J. , Tallowin J. R. B. , Smith R. E. N. 
Published: March 2003

AbstractAvailability of seeds and provision of “safe sites” for seedling recruitment are essential for successful restoration of seminatural grassland communities. Inability to provide species‐specific conditions for seedling recruitment appears to be a major factor limiting establishment of fen‐meadow species on restoration sites. This contention was tested in the field for both germination and establishment conditions for a selection of fen‐meadow species. A Cirsio‐Molinietum fen meadow and an agriculturally semi‐improved species‐poor grass dominated rush pasture were used. Seeds of Carex ovalis, Cirsium dissectum, Molinia caerulea, Succisa pratensis, and Holcus lanatus were sown onto treatments comprising either irrigation or no irrigation, presence or absence of existing vegetation canopy, and presence or absence of soil disturbance. Germination of all except H. lanatus was higher in the fen meadow than in the rush pasture. The fen‐meadow site was less susceptible to drought, provided more light to the seed environment, and showed a stronger day–night variation in relative humidity compared with the rush pasture. All the fen‐meadow species responded strongly to the experimental treatments, whereas H. lanatus showed only a small response. Soil disturbance was the major factor that increased germination. Removal of the vegetation canopy improved germination only in S. pratensis. Conditions affecting survival of seedlings were different from those affecting seed germination. Seedling survival was greater on the fen‐meadow site than on the rush pasture. Canopy presence was the major factor that reduced seedling survival. Few seedlings survived in the presence of the rush pasture canopy. Irrigation and soil disturbance were of minor importance for seedling survival on both sites. Safe sites for seed germination and seedling establishment of fen‐meadow species existed on the fen meadow even without soil disturbance and gap creation. Safe sites for seedling recruitment were not present in the rush pasture. The need for species‐specific definition of safe site characteristics at the two stages of seedling recruitment (i.e., for seed germination and for seedling survival) was demonstrated. The implications of these findings for restoration of seminatural grasslands are discussed.
Quantifying Vegetation and Nekton Response to Tidal Restoration of a New England Salt Marsh
Authors: Roman Charles T. , Raposa Kenneth B. , Adamowicz Susan C. , James‐Pirri Mary‐Jane , Catena John G. 
Published: March 2003

AbstractTidal flow to salt marshes throughout the northeastern United States is often restricted by roads, dikes, impoundments, and inadequately sized culverts or bridge openings, resulting in altered ecological structure and function. In this study we evaluated the response of vegetation and nekton (fishes and decapod crustaceans) to restoration of full tidal flow to a portion of the Sachuest Point salt marsh, Middletown, Rhode Island. A before, after, control, impact study design was used, including evaluations of the tide‐restricted marsh, the same marsh after reintroduction of tidal flow (i.e., tide‐restored marsh), and an unrestricted control marsh. Before tidal restoration vegetation of the 3.7‐ha tide‐restricted marsh was dominated by Phragmites australis and was significantly different from the adjacent 6.3‐ha Spartina‐dominated unrestricted control marsh (analysis of similarities randomization test, p < 0.001). After one growing season vegetation of the tide‐restored marsh had changed from its pre‐restoration condition (analysis of similarities randomization test, p < 0.005). Although not similar to the unrestricted control marsh, Spartina patens and S. alterniflora abundance increased and abundance and height of Phragmites significantly declined, suggesting a convergence toward typical New England salt marsh vegetation. Before restoration shallow water habitat (creeks and pools) of the unrestricted control marsh supported a greater density of nekton compared with the tide‐restricted marsh (analysis of variance, p < 0.001), but after one season of restored tidal flow nekton density was equivalent. A similar trend was documented for nekton species richness. Nekton density and species richness from marsh surface samples were similar between the tide‐restored marsh and unrestricted control marsh. Fundulus heteroclitus and Palaemonetes pugio were the numerically dominant fish and decapod species in all sampled habitats. This study provides an example of a quantitative approach for assessing the response of vegetation and nekton to tidal restoration.
Exotic Plant Species as Problems and Solutions in Ecological Restoration: A Synthesis
Authors: D'Antonio Carla , Meyerson Laura A. 
Published: March 2003

AbstractExotic species have become increasingly significant management problems in parks and reserves and frequently complicate restoration projects. At the same time there may be circumstances in which their removal may have unforeseen negative consequences or their use in restoration is desirable. We review the types of effects exotic species may have that are important during restoration and suggest research that could increase our ability to set realistic management goals. Their control and use may be controversial; therefore we advocate consideration of exotic species in the greater context of community structure and succession and emphasize areas where ecological research could bring insight to management dilemmas surrounding exotic species and restoration. For example, an understanding of the potential transience of exotics in a site and the role particular exotics might play in changing processes that influence the course of succession is essential to setting removal priorities and realistic management goals. Likewise, a greater understanding of the ecological role of introduced species might help to reduce controversy surrounding their purposeful use in restoration. Here we link generalizations emerging from the invasion ecology literature with practical restoration concerns, including circumstances when it is practical to use exotic species in restoration.
Demographic Analysis of a Disjunct Population ofFroelichia floridanain the mid‐Ohio River Valley
Authors: McCauley Ross A. , Ungar Irwin A. 
Published: March 2003

AbstractFroelichia floridana(cottonweed) occurs as a disjunct population along the Ohio River in southeastern Ohio. The anomalous occurrence ofF. floridanain this area has led to its designation as a state endangered species and a management regime to maintain the habitat conditions in which it occurs. As part of this effort, a restoration site was established on public lands in 1984 from seed collected in areas threatened by development. This study seeks to determine the demographic characteristics of this species in the restored and non‐restored managed sites to provide basic ecological information regarding life history parameters and to judge the effectiveness of the restoration. For two years (1997–1998) we collected information on seed bank abundance, field seed germination, plant survivorship, and seed production to create a stage‐based transition matrix model. The model suggests that population growth and abundance as assayed by λ (rate of increase) are stable to declining and are similar between the restoration and natural sites. A reduction in competition had a positive effect on population growth. Elasticity analysis showed that plants germinating earlier in the spring and becoming established as an early cohort contributed a greater level of reproductive output than plants germinating in late spring. Lowered population growth for 1997 is attributed to a cooler and dryer than average early spring that delayed germination and subsequent seed production. Elasticity analysis also suggested that the presence of a persistent seed bank was crucial for long‐term population maintenance and may allow for recovery in areas of low aboveground abundance through soil manipulation.
Fire Season and Dominance in an Illinois Tallgrass Prairie Restoration
Authors: Copeland Tanya E. , Sluis William , Howe Henry F. 
Published: March 2003

AbstractNorth American prairie remnants and restorations are normally managed with dormant‐season prescribed fires. Growing‐season fire is of interest because it suppresses dominant late‐flowering grasses and forbs, thereby making available light and other resources used by subdominant grasses and forbs that comprise most prairie diversity. Here we report a twofold increase in mean frequency and richness of subdominant species after late‐summer fire. Stimulation of subdominants was indiscriminate; richness of prairie and volunteer species increased in species that flowered in early, mid‐, or late season. Early spring fire, the management tool used on this site until this experiment, had no effect on subdominant richness or frequency. Neither burn treatment affected reproductive tillering of the tallgrasses Sorghastrum nutans or Panicum virgatum. Flowering of Andropogon gerardii increased 4‐fold after early‐spring fires and 11‐fold after late‐summer fires. These preliminary results suggest that frequency and species richness of subdominants can be improved by late growing‐season fire without compromising vigor of warm‐season tallgrasses.
The Relative Importance of Seeding Method, Soil Ripping, and Soil Variables on Seeding Success
Authors: Montalvo Arlee M. , McMillan Paul A. , Allen Edith B. 
Published: March 2003

AbstractWe conducted a field experiment to examine how seeding method, soil ripping, and soil characteristics affected the initial establishment and growth of seeded species and if differences among treatments persisted into the second growing season. We planted seeds into a compacted field plot where most of the topsoil had been removed. The native seed mixture of Artemisia californica, Eschscholzia californica, Eriogonum fasciculatum, Lupinus succulentus, Nassella pulchra, and Vulpia microstachys represented different seed sizes and life histories. Three seeding methods (hydroseeding, imprinting, and drilling) and three ripping depths (0, 20, and 40 cm) were combined in a factorial experiment. Soil organic matter and NO3− were used as covariates. For two years, we measured density, percent cover, mean size, and flower production of the selected species, and weed emergence. Only seeding method and soil variation affected initial establishment of natives. Small‐seeded species had higher density in imprinted and hydroseeded than drilled treatments, whereas large‐seeded species had higher density in imprinted and drilled than hydroseeded treatments. These patterns persisted with only slight modification into the second year. Weed density in year 1 decreased with soil ripping. In year 1, Vulpia height and Lupinus height and flowering were greater with drilling or imprinting than hydroseeding but were not affected by ripping. Eschscholzia, Lupinus, and Vulpia produced seeds in the first year, but only Vulpia reestablished successfully in the second year. Vulpia had high cover in the second year that increased with increasing NO3−, but did not vary by treatment. In year 2 perennial Nassella, and to some extent Eriogonum, grew largest, produced more inflorescences, and had their highest percent cover in the 40‐cm rip treatment. Size and inflorescence production also increased with increasing NO3−; sometimes this relationship was stronger than the effects of treatments. We found only positive associations between estimated biomass (density × height) of annuals and survival of shrubs. Potential for erosion control, as measured by total density in year 1 and total vegetative cover in year 2, was greatest in imprinted and hydroseeded treatments and increased with increasing NO3−. This relatively simple experiment yielded information critical to understanding optimum seeding methods and seedbed preparation and indicates that seeding method can be determined by seed size and germination biology. Although an experiment such as this enables some generalizations, it does not eliminate the need for site‐specific experiments prior to restoration.
Palatability and Chemical Defenses of Macroalgae in the Antarctic Peninsula
Authors: Amsler C. D. , Amsler M. O. , McClintock J. B. , Iken K. B. , Hubbard J. M. , Baker W. J. 
Published: March 2003

AbstractWe examined palatability of 37 species of nonencrusting macroalgae from the Antarctic Peninsula. This represents approximately 30% of the entire antarctic macroalgal flora and 75% of the 49 nonencrusting species we collected. Organic extracts from most species were also prepared and mixed into artificial foods. We examined palatability using feeding bioassays with three common, macroalga‐consuming animals (an omnivorous antarctic rockfish, Notothenia coriiceps; an omnivorous sea star, Odontaster validus; and a herbivorous amphipod, Gondogenia antarctica). Thallus pieces from 23 of 34 macroalgal species tested with the fish (68%) were rejected. Of the 23 species rejected as thallus, organic extracts of 16 were bioassayed using the fish with 9 (56%) unpalatable. Thallus pieces from 21 of 36 macroalgal species tested with the sea star (58%) were rejected. Of the 21 species rejected as thallus, organic extracts of 20 were bioassayed using the sea stars and 14 (70%) were unpalatable. Overall, 28 of the 37 species assayed as thallus (76%) were rejected by either or both the fish and sea stars. The amphipod assay was not suitable for use with thallus but was utilized with organic extracts of 23 macroalgal species that were rejected as thallus by either or both the fish and sea stars. Of these, 14 (61%) of the species' extracts were rejected by the amphipods. Unpalatability was highest among the brown algae examined with only an ephemeral, ectocarpoid species not rejected as thallus out of 10 species tested. Of the remaining nine brown algal species, six of seven tested were also unpalatable as extracts, including all the ecologically dominant, perennial species in the area. We conclude that unpalatability to herbivores is common in antarctic macroalgae and that chemical defenses may play an important role in the unpalatability of many algal species (NSF OPP9814538, OPP9901076).
Mycosporine‐Like Amino Acids in Harmful Marine Microalgae
Authors: Wulff A. , Appelgren M. 
Published: March 2003

AbstractTwo current environmental issues are the increasing occurrence of harmful algal blooms and the increasing level of ultraviolet radiation. The objective of this ongoing project is to investigate whether there is a coupling between these two phenomena, i.e. to test the hypothesis that UV‐B radiation functions as a selective pressure favoring surface‐blooming toxic/harmful marine microalgal species capable of producing UV‐absorbing compounds (mycosporine‐like amino acids, MAAs). A series of experiments were designed to test if the light environment induces the production of MAAs. Treatments were PAR with and without the addition of UV‐B radiation. Preliminary results show a different response for different species. Most species increased their production of MAAs when exposed to an increased PAR intensity (300 µmol photons/m2/s) and in, e.g. Alexandrium ostenfeldii and Gyrodinium aureolum a further increase was observed upon exposure to UV‐B radiation. The content and composition of MAAs for a number of potentially harmful marine microalgae will be shown. In addition, the outcome of small changes in the HPLC method used will be discussed.
Macroalgae of the Hawaiian Islands: 23 Additional Stream Segments
Authors: Filkin N. R. , Sherwood A. R. , Vis M. L. 
Published: March 2003

AbstractThe Hawaiian Islands are located 3700 km from the nearest continental land mass and as such provide an interesting research opportunity to study freshwater organisms intolerant of seawater. The freshwater biota have been only partially studied with little research on the stream macroalgae. The only previous study to focus solely on stream macroalgae, reported 25 new species to the Hawaiian Islands from 34 stream segments sampled. The purpose of our study was to expand the sampling of streams to better determine macroalgal distributions and species richness. Twenty‐three additional stream segments (seven on Oahu, eight on Kauai and eight on Hawaii) were sampled for macroalgae. The physical and chemical parameters of each stream were measured. Stream segments ranged greatly in size from 1.2 to 40 m in width. Water temperature was relatively uniform (about 21 °C) but other chemical parameters differed from site to site (pH 5.5–8.9, specific conductance 20–200 mS/cm). Mean species richness per stream segment was 3.9 with one to eight species collected per segment. Ninety populations of 44 infrageneric taxa were identified from the Cyanobacteria (20), Chlorophyta (18), Rhodophyta (3) and Chrysophyta (3). The most abundant taxa were Spirogyra sp. 2, Audouinella pygmaea and Phormidium retzii. All three of these species are cosmopolitan. Twenty‐two of the taxa are new records for streams in the Hawaiian Islands. The large percentage (50%) of new taxa suggests that more research is needed to fully catalog the Hawaiian stream macroalgal diversity.
The Diversity and Availability of Caulerpa Species Found in Retail Aquarium Outlets in Southern California, USA
Authors: Frisch S. M. , Murray S. N. 
Published: March 2003

AbstractBiological invasions are recognized as a serious threat to marine biodiversity. Within the last 2 years, invasive populations of Caulerpa taxifolia were found in southern California's coastal waters as well as in New South Wales, Australia. In addition, two other seaweeds (Undaria pinnatifida and Caulacanthus ustulatus) also appear to have recently invaded southern California's warm temperate waters. The introduction of C. taxifolia has attracted much attention because this exotic seaweed is thought to have significantly altered the structure of Mediterranean marine ecosystems following its 1984 invasion. The southern California inoculation of C. taxifolia is believed to have resulted from the release of aquarium specimens. Besides C. taxifolia, other species of Caulerpa being sold for aquarium use also may have the potential to invade temperate waters. As a first step towards making this determination, the availability (% frequency) of Caulerpa species being sold in southern California for aquarium use was ascertained. Fifty retail saltwater aquarium stores were visited in three southern California counties between November 2000 and August 2001. Sixteen Caulerpa taxa were identified from the retail aquarium outlets. Caulerpa species were sold in 52% of these stores. C. taxifolia, ‘Mediterranean form’, was offered for sale in 10% of the visited stores; C. serrulata var. hummii (18%), C. racemosa (14%), and C. racemosa var. lamourouxii (14%) were the most commonly sold species. These data indicate that the aquarium industry is bringing into the region other species of Caulerpa besides C. taxifolia. Some of these species may also have the potential to invade temperate waters.
Relationship Between Periodic Resuspension Events and Planktonic Diatom Community Structure in Lake Michigan: A Field and Laboratory Investigation
Authors: Julius M. L. 
Published: March 2003

AbstractLake Michigan provides an ideal location for comparing episodic physical forcing events (storms) on phytoplankton processes and the more persistent seasonal variability of phytoplankton communities. This is due to the duration and extent of the highly turbid, recurrent coastal plume (RCP) in the lake during the winter/early spring. Although the RCP can coincide with the initiation of the basin wide spring diatom bloom, linkages between the duration and intensity of the plume and the prominent role of light availability in regulating Lake Michigan phytoplankton growth during the spring isothermal period have been postulated, but not verified. The concurrent physical and biological events provide a novel opportunity to examine phenomena associated with the RCP affecting the distribution and abundance of species in Lake Michigan's planktonic diatom flora. In this study, planktonic diatom assemblages from pre, post and active spring plume events were examined from stations along Lake Michigan's southern shoreline. Species abundance changed rapidly during storm events. Sediment resuspension via storm activity created a suboptimal growth environment. Post‐storm event diatom phytoplankton communities were floristically distinct from prestorm event communities, with resting cell‐forming taxa playing a significant role in these community‐restructuring periods. Laboratory simulations of resuspension events using Lake Michigan sediments were conducted under a variety of environmental conditions. Parameters varied included day length, temperature, and silica. The resulting assemblages were quantitatively counted. A statistically significant relationship was identified between day length and the vegetative growth of many resting cell‐forming diatom species. When day length was calculated for poststorm event field data, it revealed a high correlation between poststorm event communities and those predicted by the laboratory simulations. Timing of storm events and latitudinal position of the aquatic system are then important elements for consideration when predicting diatom phytoplankton community structure due to the relationship these factors have with day length.
Public Outreach Materials Regarding Harmful Algal Blooms and Their Possible Effects on Human Health
Authors: Kirkpatrick B. , Fleming L. E. , Stephan W. B. , Backer L. , Clark R. , Squicciarini D. , Weisman R. , Van De Bogart G. 
Published: March 2003

AbstractThe potential interactions between marine and freshwater harmful algal blooms (HABs) and humans are increasing. Humans are exposed through food, drinking water, and recreational and occupational water use to an increasing number of organisms and their toxins. Nevertheless, the amount of clinical and epidemiologic research concerning acute and chronic human health effects from the HAB organisms and their toxins is relatively sparse. At the same time, the public is increasingly aware of and interested in the potential dangers associated with exposure to HABs. Public health authorities and researchers must respond to these public health concerns. The development of appropriate educational and outreach materials based on limited scientific databases is the challenge of informing the public concerning the possible human health effects of HAB organisms and their toxins, and their prevention. Educational materials developed by a group of researchers and public health personnel for general HABs, Florida Red Tide Toxins (brevetoxins), Cyanobacteria, and Ciguatera are discussed, as well as methods for their dissemination.