Glenn D. Dreyer

Influence of Land Use and Site Characteristics on Invasive Plant Abundance in the Quinebaug Highlands of Southern New England

Abstract Invasive exotic plants have been identified as one of the major threats to ecosystem function and biodiversity. This study examined the distribution and abundance (cover and frequency) of invasive plants in natural habitats of the Quinebaug Highlands forest block (13,760 ha) of northern Connecticut and southern Massachusetts in relation to current and historical land use and site conditions. Multiple regression and GIS analyses were used to identify areas of high infestation and factors most useful in predicting invasions. Celastrus orbiculatus, Rosa multiflora, and Berberis thunbergii were the most frequent invasives. Past land use was the strongest predictor of invasive cover (r2 = 0.219) and richness (r2 = 0.303; p < 0.001 both regressions). Current land development and physical soil characteristics were also strongly correlated. These results add to our understanding of factors promoting plant invasions. Because invasive species control in natural areas is time- and resource-intensive, this information may enhance conservation efforts by increasing efficiency in predicting and managing biological invasions.

Changes in a hemlock-dominated forest following woolly adelgid infestation in southern New England1

Abstract Small, M. J., C. J. Small (Department of Botany, Connecticut College, New London, Connecticut 06320), and G. D. Dreyer (Goodwin-Niering Center for Conservation Biology and Environmental Studies, Connecticut College, New London, Connecticut 06320). Changes in a hemlock-dominated forest following woolly adelgid infestation in southern New England. J. Torrey Bot. 132: 458–470. 2005.—The hemlock wooly adelgid (HWA; Adelges tsugae), a small aphid-like insect introduced from Japan, has caused widespread hemlock (Tsuga canadensis) mortality throughout the mid-Atlantic and southern New England region over the last twenty years. We examined long-term (1952–2002) changes in hemlock-dominated stands before and after the appearance of the HWA in 1987 in the Connecticut College Arboretum, southeastern Connecticut. With HWA infestation, basal area of T. canadensis declined dramatically, dropping 70% from 1982 to 2002. Forest communities responded to the elimination of the dominant species by quickly filling various sized gaps. Black oaks (Quercus velutina, Q. coccinea, Q. rubra) increased from 28% of canopy basal area in 1982 to 41% in 2002. Sapling density increased markedly following HWA infestation, from 80 stems/ha in 1982 to nearly 5600 in 2002, with greatest increase in Sassafras albidum (0 to 1900 stems/ha) and Acer rubrum (4 to 1100 stems/ha). Ledge and ravine communities, formerly dominated by T. canadensis, became more compositionally distinct, with greater importance of black oaks on more xeric ledge sites and mixed canopy dominance in mesic ravine sites. Major trends associated with the decline of T. canadensis included a shift in canopy dominance to oak and mixed hardwoods, considerable understory development, including greater herb richness and abundance and increased density of clonal saplings, and expansion of several invasive shrubs and woody vines.

Effects of prescribed burning on Andropogon scoparius in postagricultural grasslands in Connecticut.

-Since 1968 postagricultural Andropogon scoparius grasslands have been subjected to annual and biennial burning. After 17 years of burning, Andropogon standing crop has increased averaging 364 g/m2 compared to 252 g/m2 when unburned. Baptisia tinctoria, a fire increaser and nitrogen fixer, increased in density 2and 3.5-fold with annual and biennial burning, respectively. Woody growth was stem-killed, but resurged following each burn. Clonal species such as Gaylussacia baccata and Comptonia peregrina increased 3and 4-fold, respectively, after more than a decade of burning. Where nonclonal woody species were present in burn plots, there was little change in woody cover; unburned plots have become dominated by woody growth. A multifactor, qualitative working model involving increases in light, soil moisture and temperature, mineralization, nitrogen-fixing species and ash is proposed to explain why Andropogon standing crop increases with burning. The use of fire favors perpetuation of a native eastern prairie grassland somewhat similar to that which previously existed in the Hempstead Plains of Long Island, New York. The use of prescribed burning has considerable potential in wildlife management and ecosystem restoration and in maintaining graminoiddominated landscapes within this oak forest region.

Evaluation of two herbicide techniques on electric transmission rights-of-way: development of relatively stable shrublands

Postmanagement vegetation patterns were studied on five transmission rights-of-way subjected to over a decade of basal or stem-foliar herbicide applications designed to eliminate tall-growing trees. The basally treated lines had a mean of 100% greater shrub and 50% less herbaceous cover than stem-foliar treated lines due primarily to the lack of overspray damage to nontarget plant species with the basal technique. Persisting tree growth was also 50% less with basal treatments whenSassafras albidum, a rootsuckering problem species on all areas, was excluded. Tree seedling establishment on basally treated rights-of-way was 34% less than on stem-foliar treated lines. The creation of stable shrublands can potentially reduce the amount of future herbicide usage. These findings also lend support to the Initial Floristic Composition concept in vegetation development proposed by Egler. In southern New England, commercial basal applications can effectively control unwanted tree growth on rights-of-way while promoting the development of relatively stable shrublands which tend to inhibit the invasion of tree seedlings.

Vegetation classification and invasive species distribution in natural areas of southern New England1

Abstract Invasive plant species pose serious threats to ecosystem function and community diversity, dominating many natural systems through suppression of, competition with, and replacement of native species. This study examines the distribution of invasive alien plant species relative to vegetation, site characteristics, and disturbance indicators in a relatively unfragmented matrix forest block (∼8,000 ha) in southern New England and provides the first quantitative description of the forested vegetation of this region. Within 139 - 10 × 10 m sample plots, percent ground coverage was estimated for each vascular plant species and basal area determined for all woody species reaching breast height (1.4 m). Site conditions, including topography, soil moisture and fertility, and evidence of current and historical site disturbance, were assessed to identify factors influencing invasive plant abundance. Fifteen relatively distinct vegetation types were identified using NMS ordination and cluster analysis, including wetland forest, terrestrial open woodland, and terrestrial closed canopy vegetation types. Of the 209 species occurring in sample plots, only 10 (4.8%) were invasive. Most abundant were Berberis thunbergii, Celastrus orbiculatus, and Rosa multiflora, each occurring in 5% or fewer plots. Moist sites were invaded most frequently, especially those with high species richness, lower canopy cover, and those dominated by Acer rubrum or Pinus strobus. Site disturbance, particularly roads, trails, and former land use, also was correlated with invasive abundance. The low frequency of invasive plant species in our study area offers an exceptional opportunity to identify ecosystem characteristics inhibitory to invasive plant species and the opportunity to preserve a series of relatively unfragmented and uninvaded natural habitats in this region.

Saving Biological Diversity: An Overview

The conservation movement in North America emerged in part due to the shock of the extinction of the passenger pigeon and the near extinction of the American bison, species that had once been considered too numerous to be depleted. By the 1960s, a broad consensus emerged in the United States that species should not be driven to extinction by human activity. Since then, however, the Endangered Species Act and major programs to restore endangered and threatened species have become controversial. Private property rights advocates claim that endangered species protection hampers economic activity and land development to an unreasonable extent. At the same time some conservationists are concerned that too much money and effort are devoted to endangered species, diverting efforts from protection of entire ecosystems that support numerous species. They argue that given the limited resources available, preventing common species from becoming rare is the most effective long-term strategy. Defenders of endangered species programs claim that protecting endangered species usually entails protecting entire ecosystems, and endangered species can serve as effective symbols to rally support for ecosystem protection. Saving Biological Diversity: Balancing the Protection of Endangered Species and Ecosystems seeks to emphasize the interplay between the science and policy of species protection. We have chosen to take a broadly interdisciplinary approach by focusing on such important topics as the effectiveness and economics of endangered species protection, efforts to sustain biological diversity in entire ecosystems or across regional landscapes, and the need to protect species diversity on a global scale. Our book is a synthesis of the views of economists, political scientists, resource managers and conservation biologists on a wide array of species protection issues. In a single book we could not hope to address the myriad species, habitats, ecosystems, conservation issues and political systems worldwide that a truly comprehensive treatment would require. Instead we present chapters illustrating a wide range of problems and solutions as they are seen by people who work in an array of disciplines and professions. Since our authors come from different academic traditions, the editors have chosen to tread lightly on preferred writing and referencing styles. While this results in some distinct stylistic differences between those authors with a legal background and those with scientific training, it does not detract from the communication of important ideas. Our goal for this book is to engage a wide audience that includes researchers, concerned citizens, regulators, conservation managers and policy analysts. Saving Biological Diversity may also serve as a book of readings for courses in conservation biology, environmental studies, or environmental policy. We believe that the juxtaposition of

THE HISTORY, STATUS, AND FUTURE OF THE NEW ENGLAND OFFSHORE FISHERY: INTRODUCTION TO THE PROCEEDINGS

Any regular reader of a New England daily newspaper is aware that all is not well in our offshore waters. Commercial harvests of fish have been dropping and many fish populations are in trouble globally, even in our own Northwest Atlantic region. In 1995, the National Marine Fisheries Service surveyed 201 species groups of US fish and judged over 60% to be either fully or over utilized. By 1998, the National Academy of Sciences estimated that 80% of commercially harvested fish species were fully or over utilized. Declines in fish stocks and subsequent fishing restrictions have translated into huge decreases in income and employment opportunities, both in New England and adjacent Canada. One report indicates closures to fishing on Georges Bank in the early 1990s cost 14,000 jobs in New England while Grand Banks closures caused 30,000 to become unemployed in Newfoundland. Most recently, in southern New England, a still mysterious die-off of lobster in Long Island Sound has thrown what was once a fairly stable segment of the industry into complete turmoil. Contrary to the general consensus on declines in numbers of commercial fish and in the number of people employed in the industry, there is considerable debate about the cause of the problem. How much is simply due to overfishing and how much to misguided regulation, pollution, or other factors is hotly debated. The History, Status, and Future of the New England Offshore Fishery Conference, held at Connecticut College in April 1999, was the second such gathering sponsored by the Goodwin-Niering Center for Conservation Biology and Environmental Studies. Like its predecessor, which dealt with the topic of New England forests (proceedings in Northeastern Naturalist 5(2), 1998), this two-day meeting was designed to examine a fairly specific subject from as many different points of view as possible. Our goal was to produce an insightful overview of current scientific, regulatory, economic, sociological, and conservation perspectives on the New England offshore fishery. We began planning this event shortly after the reauthorization of the Magnuson-Stevens Act, which governs federal management of fisheries outside of coastal state waters. In the spirit of Connecticut College’s mission to foster the liberal arts, we held our ban-