BioOne.org will be down briefly for maintenance on 14 May 2025 between 18:00-22:00 Pacific Time US. We apologize for any inconvenience.
Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact helpdesk@bioone.org with any questions.
Callery pear is an invasive nonnative species that was introduced to the United States as an ornamental tree. Previous work on its stand structure has suggested that Callery pear is mid-shade-tolerant or shade-intolerant. The shade tolerance of plants can also be determined by examining their spatial distributions. I selected nine stands dominated by Callery pear in northern Kentucky and southwest Ohio. At each site I laid out a 10 m × 10 m grid and recorded the position of each pear tree, as well as its diameter. Diameters were fit to a two-factor Weibull distribution to determine the shape parameter of diameter distributions. I also determined the pair correlation (nearest neighbor) function ĝ(r), which is related to Ripley's K, to look for patterns of distribution. To look for associations among size classes at each stand, bivariate Ripley's 12(r) functions were determined. Overall, trees were randomly distributed, with no associations among size classes. However, the smallest size classes often showed clustering, while the larger size classes rarely did. These distribution patterns follow those typically seen in shade-intolerant plants with bird-distributed seeds. While a shade-intolerant species would ordinarily be confined to open and disturbed areas, Callery pear's extended leaf phenology and documented invasion of forests suggest it may become a problem in closed-canopy forests.
Lack of fire and increasingly wet conditions in eastern North America are thought to interact in a way that depresses the recruitment of fire-adapted species like Quercus and Carya while promoting the growth and recruitment of mesophytic species like Acer. This process, referred to as forest mesophication, has tended to focus on the consequences for Quercus with more limited attention on Carya. Additionally, forest mesophication has the potential to alter traditional forest community and topographic relationships as environmental conditions continue to shift. This study questioned if Carya populations have responded to forest mesophication over the last 38 yr. Also, this study questioned if long-term changes in forest composition maintained traditional aspect-species relationships in response to forest mesophication. In Athens County, Ohio, forest surveys of Carya and associated overstory, midstory, sapling, and seedling vegetation were conducted in 1983 and 2021. Survey results from 1983 and 2021 were analyzed to determine shifts in Carya population structure and shifts in forest community composition and diversity. Carya populations decreased by approximately 50% since the original 1983 survey across all species, topographic positions, and aspects. Current populations are composed of mostly large individuals with little evidence of recruitment over the last several decades. The midstory and sapling forest layers have experienced decreases in species diversity, mostly through increases in Acer and Fagus grandifolia Ehrh., and decreases in Quercus and Carya. Species compositions from the sapling and seeding layers retained aspect differences and reflected overstory species compositions. The midstory and overstory layers have experienced shifts in species composition over time with the midstory layer no longer retaining topographic and aspect relationships with species composition. Changes in forest composition may be trending towards a loss in topographic distinction in species composition for forest communities in the region. Carya populations appear unlikely to remain a significant portion of the forest community given the observed lack of recruitment into larger size classes past the sapling stage. Long-term changes in forest composition, due in large part to mesophication, are becoming evident and have the potential to drastically alter forest composition in the very near future without direct intervention.
Mountain ecosystems face increasing disturbance impacts (e.g., wildfire) due to climate change, leading to significant changes in vegetation composition and landscape dynamics. Clonal plants, characterized by their vegetative reproduction strategies, offer a range of ecologically important traits to cope with disturbances. However, clonality is often excluded in postfire vegetation studies in mountain ecosystems, and our knowledge of the ability of clonal plants to respond to differing disturbance regimes is limited. We studied the response of understory vegetation, based on composition and clonal traits, in burned and unburned Pinus ponderosa Lawson & C. Lawson (ponderosa pine) stands in the Colorado Front Range. Data from 40 total burned (n = 20) and unburned plots (n = 20) (10 m × 10 m) included relative plant cover and five environmental variables. Burned plots had greater overall clonal plant cover and diversity compared to unburned plots. Although there were statistically distinct differences in species composition between burned and unburned plots, these differences may not be ecologically meaningful. A fourth-corner analysis showed relationships between elevation and slope and type of clonal growth organs, suggesting that elevation, slope, and fire history interact significantly in shaping vegetation community structure. Combined responses of lateral spread and ramet length of Arctostaphylos uva-ursi L. (kinnikinnick) differed significantly in areas impacted by wildfire to those unburned, whereas that of Antennaria parvifolia Nutt. (small-leaf pussytoes) showed no differences, suggesting a species-specific response of clonal traits following fire. Our findings indicate that clonal plants dominate the understory in burned P. ponderosa stands. We suggest managers and modelers account for plant clonal traits for a comprehensive understanding of postfire forest recovery.
Morgan L. Vis, Gabriella A. Lindsey, Sarah J. Shainker-Connelly, Roseanna M. Crowell, Alexis P. Oetterer, Brinkley M. Thornton, Stacy A. Krueger-Hadfield
The state of Michigan is 253,800 km2 in size with abundant freshwater habitats, including lakes, streams, ponds, and rivers that are ideal for freshwater red algae from the order Batrachospermales. In addition, there are numerous herbarium records, but approximately 60% are more than 20 years old. Recent collections have been from a small geographic area and only a handful of specimens have associated DNA sequences that are often needed for accurate species identification. We surveyed broadly in the Upper and Lower Peninsula, revisiting previously sampled sites and exploring new localities. Freshwater red algae were collected from 19 sites that varied from small streams, rivers, and lake inlet/outlets with a corresponding range in water temperature, pH, and conductivity. Four genera were collected, Batrachospermum, Paludicola, Sheathia, and Virescentia, with species identifications verified with rbcL gene sequencing. The genus Sheathia was the most abundant (15 sites) and represented by two species, S. grandis and S. involuta. At seven sites, we found Batrachospermum gelatinosum, whereas Paludicola communis and Virescentia viride-americana were each collected once. Although these four genera have been previously known from the state, this study provided the first rbcL sequence for B. gelatinosum and P. communis in Michigan. At one location, we confirmed the presence of Virescentia viride-americana 30 years after it had first been collected, and likewise, we confirmed B. gelatinosum at another site 27 years later. Sheathia grandis was recently described from only two locations in nearby states. This study was the first report in Michigan and added considerably to the number of known locations. This research has yielded new records, species identification with DNA sequence, and expanded habitat information.
The genus Phallus, popularly known as stinkhorns, includes representatives characterized by phaloid form, mucilaginous gleba with a passive dispersal mechanism of basidiospores associated to insects. In Brazil, the records of Phallus species are concentrated in the South and Southeast regions of the country, some identifications are mistaken, and studies are insufficient to estimate biodiversity of the genus. In this context, the present study aimed to contribute with two new Phallus records for Brazil, inventory Phallus species described for Brazil, and develop an identification key. Collections were conducted in the municipalities of Barbalha-CE (Parque Ecológico Municipal Riacho do Meio) and Crato-CE (Parque Estadual Sítio Fundão). The basidiomata collected were herborized, underwent morphological analysis, and were identified based on specific literature. The species P. squamulosus was identified, characterized by an unexpanded basidiome and volva with a scaly surface and white receptacle with shallow reticulations and a wide apical pore. This is the third record for science and the first for the Semiarid Northeast. After review of Phallus records for Brazil in the literature (articles and books), we concluded that there are 14 species of Phallus in Brazil. In the checklist of the genus Phallus, we have included synonymies, collections, type locality, GenBank information, records for Brazil, including state, city, biome, voucher used in the description, and reference. We also present additional information on the species: diagnostic characters, discussion, taxonomic problems, references for illustrations and description, DNA sequencing data deposited in GenBank, and information from Brazilian collections. The identification key for Phallus species recorded for Brazil was based on the macro- and microscopic characters of the basidiomata. The study will contribute to the taxonomy and systematics of the genus Phallus and will serve as a basis for new taxonomic studies and for the identification of new specimens collected in Brazil and other localities.
Over the years, many studies with Lycoperdon have been carried out in Brazil, but none include the state of Bahia, one of the states with the largest number of biomes in the country. The aim of this study is to present the first occurrences of this genus for the state of Bahia and provide a checklist for the species of this subgenus cited for Brazil and a taxonomic key for all species in the world. Collections were made in the municipalities of Elísio Medrado, Miguel Calmon, Mucugê, Igrapiúna, and Uruçuca. After analysis, three species were identified: Lycoperdon arenicola, L. fuligineum, and L. nudum. All species characterize the first occurrences for the state of Bahia. Descriptions, photos, and SEM of the analyzed material are provided. In addition, a checklist and taxonomic key for subgenus Morganella are provided.
This article is only available to subscribers. It is not available for individual sale.
Access to the requested content is limited to institutions that have
purchased or subscribe to this BioOne eBook Collection. You are receiving
this notice because your organization may not have this eBook access.*
*Shibboleth/Open Athens users-please
sign in
to access your institution's subscriptions.
Additional information about institution subscriptions can be foundhere