RESTORATION & INVASIVE SPECIES 9:00 AM SATURDAY, MARCH 31, 2001 KOLENBRANDER-HARTER ROOM 203 CAROLYN MCQUATTIE-PRESIDING.
Although many studies have shown general community modifications by invasive plants, few have examined the effects of invasive species on the trajectory of succession. The goal of this investigation was to examine a chronosequence of Amur honeysuckle (Lonicera maackii) invasion and study its effects on vegetation. Sixteen forest stands in southwestern Ohio were studied: 12 honeysuckle invaded sites of various ages and 4 non-invaded control sites. Trees were increment cored (n = 224) to determine stand age, and honeysuckle stems were cut and aged (n = 448) to determine time since invasion. Soil cores were collected (n = 224), and seeds were grown to study germinable seed composition. At fourteen points per site, the forest layers including herbs, tree seedlings, saplings, shrubs, and canopy were quantified. Of all species honeysuckle showed the greatest seedling recruitment ability (mean density = 3.7 [stems.sup.x][m.sup.2] [+ or -] 1.2 SE; density range = 0.3 to 18.3 [stems.sup.x][m.sup.2]). Honeysuckle age (11.5 yrs [+ or -] 1.1; max = 42) was not significantly (P [is greater than] 0.05) correlated with canopy age (mean = 55.6 yrs [+ or -] 5.6; max = 119) indicating broad invasibility by honeysuckle in terms of stand maturity. Honeysuckle biomass at sites ranged from 49.3 to 1147.8 [kg.sup.x][ha.sup.-1] (mean = 316.5 [kg.sup.x][ha.sup.-1] [+ or -] 68.7). Richness and Shannon-Weiner diversity of seedbanks, herbs, tree seedlings, and saplings were negatively related to honeysuckle biomass ([R.sup.2] = 0.83, P = 0.04). This suggests that honeysuckle dominance in stands could adversely affect community diversity and succession.
09:15 SURVIVAL, GROWTH, AND FECUNDITY OF TWO UNDERSTORY PERENNIAL HERBS IN THE PRESENCE AND ABSENCE OF THE EXOTIC INVASIVE SHRUB LONICERA MAACKII (AMUR HONEYSUCKLE). Kara E. Miller, email@example.com, David L. Gorchov, firstname.lastname@example.org, Miami University, Department of Botany, Oxford OH 45056.
Studies that examine invasive species and invaded communities rarely quantify direct effects of invasive plants on native species. We investigated effects on understory herbs of the exotic shrub Lonicera maackii(Rupr.) Herder (Amur Honeysuckle), which has invaded forests in eastern North America. Transplants of 120 individuals each of Anemonella thalictroides L. (Rue-anemone) and Allium burdickii (Hanes) A.G. Jones (Wild Leek) were placed in a blocked design of three treatments (L. maackii present, absent, and removed) at an anthropogenically disturbed and an undisturbed forest stand in Oxford, Ohio (Butler County). Herb demography was monitored for 4-5 seasons following transplanting to test the hypothesis that L. maackii reduces herb survival, growth, and fecundity. Log-likelihood tests revealed that A. thalictroides individuals survived equally well in all treatments at the undisturbed site, and had higher survival under L. maackii in the disturbed forest. At the undisturbed site A. burdickii survival was higher in the shrub's presence, but no significant difference was detected at the disturbed site. Growth, as determined by average leaf number (A. thalictroides) or sum of leaf widths (A. burdickii), occurred in all treatments at both sites, but was greatest for individuals in the absent or removal treatments (mixed model ANOVA). Lonicera maackii reduced the proportion of A. burdickii flowers at the disturbed site, and reduced flower and seed number per plant for both species at both sites. These results suggest that L. maackii does not reduce survival of perennial forest herb individuals, but hinders population growth of these species due to reduced growth and fecundity.
09:30 COMPARISON OF STANDING HERBACEOUS VEGETATION AND SEED BANK COMPOSITION OF A RESTORED PASTURE. Cathlene I. Leary, learyci@email@example.com, Carolyn Howes Keiffer, firstname.lastname@example.org, Miami University, Department of Botany, Oxford OH 45056.
In areas of anthropogenic disturbance, effective means of restoration are necessary to re-establish functional communities and habitats. Disturbances related to restoration planting have the potential to influence this process by exposing the seed bank. Different planting regimes were evaluated in restoring a pasture to a lowland forest on an industrial site in southwestern Ohio (Butler County). Eight 0.1 ha plots were established of four treatments, with 2 replicates of each: Control (no planting), Seedlings (120 individuals of 5 species planted), Saplings (200 individuals of 5 species planted), Mixed (120 seedlings, 100 saplings, each of 5 species). Changes in herbaceous vegetation composition were observed among the eight plots by the end of the first growing season. The seed bank was evaluated to determine if differences in above ground vegetation observed among plots could be explained by differences in composition of the seed bank. Based on cluster analysis, the seed bank and above ground vegetation composition form two discrete groups, suggesting the seed bank does not fully explain standing vegetation. Results indicate that the seed bank and standing vegetation had a similarity of 33% (Sorensen's index) overall with similarity ranging from 17% to 31.5% among plots. Further analysis will investigate whether seed bank composition combined with micro-environmental differences among plots may be driving the herbaceous vegetation changes observed.
09:45 SPATIAL DISTRIBUTION AND SPREAD OF GARLIC MUSTARD FROM NASCENT FOCI. Daniel R. Scott, dr email@example.com, and Emilie E. Regnier, firstname.lastname@example.org. The Ohio State University, Dept. Hort and Crop Science, 2021 Coffey Rd., Columbus OH 43210.
Garlic mustard is an exotic weed of the forest understory that is competing with native spring ephemerals. It spreads rapidly through a site from low-density nascent foci that eventually merge to form a high-density population with a large front. A study was initiated in 1998 and continued through 2000 to quantify the spread of nascent foci in established wood lots. Plots were selected at three sites in Ohio: Buck Creek State Park, Clark County; Badger Farm of Ohio Agricultural Research and Development Center (OARDC), Wooster; and Western Branch OARDC, Clark County. The sites selected were based on remoteness of small populations of garlic mustard rosettes. Grids were established on each plot as 0.5 meter per side blocks. The area occupied by seedlings in 1999 was on average 53% to 170% greater than 1998 at the three sites. The area occupied by rosettes in 2000 increased by an average of 161% over the first season (1998) at Wooster, OH. The density of each plot increased by an average of 8.3% at Wooster. The number of rosettes in 2000 was an average of 301% higher than the number of rosettes in 1998 at Wooster and 588% greater at Western. Rosette numbers declined by an average of 43% and the area occupied by rosettes declined by an average of 18% at Buck Creek State Park. This was attributed to lower rainfall. Approximately 30% of 1999 seedlings survived to flower in 2000. Elimination of these nascent foci should be the primary goal for controlling garlic mustard.
10:00 STAND RESPONSE TO HEMLOCK WOOLLY ADELGID INFESTATION IN CONNECTICUT. Aaron R. Weiskittel(1), email@example.com, and David A. Orwig(2), firstname.lastname@example.org. (1) The Ohio State University, School of Natural Resources, 2021 Coffey Road, Columbus, OH 43210-1095 and (2) Harvard University.
Understanding the response of stands infested with hemlock woolly adelgid (HWA, Adelges tsugae) is a critical step in identifying the influences this introduced insect will have on ecosystem processes and landscape dynamics. Stand response was examined by establishing 24-400 [m.sup.2] sample plots within eight recently infested Tsuga canadensis (eastern hemlock) stands greater than three ha in size. Within these plots, species, diameter at breast height (dbh), crown class, and vigor were recorded for all living and dead trees greater than ten cm dbh. Increment cores were taken from 24 randomly selected living trees in each stand. Age ranged from 81 to 116 years, with total basal area between 39 and 62 [m.sup.2]/ha. Overstory hemlock mortality was between zero and seven percent and all crown classes were affected by HWA. The average hemlock tree in sites with high mortality lost 50 to 75% of their foliage, while hemlock trees in sites with moderate mortality on average had 25 to 50% foliar loss. From 1992 to 1998, hemlock growth on sites with high mortality decreased over fourteen percent annually and hemlock growth on sites with moderate mortality decreased nearly twenty percent annually between 1996 and 1998, illustrating that the physiological damage caused by HWA on an individual tree is the most severe in the first few years of infestation. Betula lenta (black birch) and Acerrubrum (red maple) were the primary species regenerating in these stands. Thus, these hemlock stands will continue to deteriorate slowly, which will alter microenvironment conditions, nutrient-cycling, and decomposition rates of these ecosystems.
10:15 THE EFFECTIVENESS OF THE EZJECT CAPSULE INJECTION SYSTEM[TM] IN THE ERADICATION OF THE INVASIVE SHRUB, LONICERA MAACKII, AMUR HONEYSUCKLE. Cybil R. Franz, email@example.com. and Carolyn Howes-Keiffer, Miami University, 4200 E. University Blvd., Middletown OH 45042.
Amur honeysuckle (Lonicera maackii) is a non-native shrub that is aggressively invading open fields and forests in the Midwest. Because current methods of removal are difficult or time consuming; we field-tested a new device (EZJECT Capsule Injection System[TM]), which directly injects herbicide into the cambium layer. We conducted two studies to determine if the EZJECT would be successful in the eradication of L. maackii and comparing effectiveness between methods of injection. Our first experiment was undertaken in the summer of 1998 when we injected 947 shrubs of various sizes. A survey conducted two months after injection, indicated that 78% of the treated shrubs were dead. The second study began in the Spring of 1999, to determine if seasonal translocation would affect survival. For this study, we used 100 shrubs total; half were injected in the spring and the remaining half in the fall. We also subdivided each season into two groups and injected herbicide into either the main stem only or into all stems of each individual. A survey, conducted 6 months after injection, indicated that the spring-injected shrubs had 56% mortality, while the fall-injected group experienced 80% mortality. Injecting all stems was more successful than only injecting the main stem. The fall treatment group exhibited 88% mortality, when all stems were injected. Based on our studies, the best practice of using the EZJECT against Amur honeysuckle is to inject in the fall, making sure to inject all stems that are large enough to accommodate a capsule.
10:30 COMMUNITY AND ALLELOPATHIC EFFECTS OF THE EXOTIC SPECIES, LESPEDEZA CUNEATA G.DON (FABACEAE), ON OLD FIELD VEGETATION. Wendy M. Dobrowolski, firstname.lastname@example.org, Irwin A. Ungar, Ohio University, Department of Environmental and Plant Biology, Porter Hall, Athens OH 45701.
The exotic species Lespedeza cuneata, Chinese lespedeza, was introduced into the United States in 1896 from eastern Asia. The goal of this project was to determine the effects of L. cuneata on the diversity and density of the old field plant communities by observing a population at Waterloo Wildlife Experimental Station (WWES) in southeastern Ohio. Its presence has been hypothesized to dramatically decrease native plant diversity as it establishes and spreads throughout a region. In order to determine the effects of L. cuneata on the plant community, four types of observational plots were set up at Waterloo Wildlife Experimental Station (WWES) to observe species composition, diversity and density of the plant community throughout the growing season. Results indicated that L. cuneata did significantly decrease plant diversity and density. The second objective of this project was to determine if allelopathy is a mechanism by which L. cuneata succeeds. Germination and growth experiments, using L. cuneata plant parts and phenolic compounds, were conducted to address this issue for four target species Tridens flavens, Daucas carota, Setaria faberi, and Solidago canadensis. The germination of S. canadensis and the germination and growth of D. carota were significantly inhibited by the phenolic compounds found in L. cuneata. Phenolic compounds in L. cuneata were shown to be highest in leaves, then seeds, roots, stems, dead stems, and soil, respectively.
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|Publication:||The Ohio Journal of Science|
|Date:||Mar 1, 2001|
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