Sericea lespedeza is an aggressive invasive plant which can suppress and displace native plant species in grasslands and prairies in the United States. The goal of the study is to determine how large the seed bank of lespedeza might be. Furthermore, the author tries to determine if a pre-emergent herbicide treatment could suppress Lespedeza germination and whether this provided benefits to a typical native species propagated into the site.
In the work, the author first characterized the soil seed bank at different invaded sites on SIUE campus using the seedling emergence method. In the second part, the author assessed the success of a pre-emergent herbicide in preventing the germination of lespedeza seed bank after lespedeza removal. The growth of a native grass (Sorghastrum nutans) as a replacement species has also been evaluated.
Currently Sericea lespedeza is rapidly spreading throughout the U.S and has been estimated to eventually invade about 61percent of the total land area. Lespedeza has become a successful colonizer because of its ability to tolerate and thrive under a wide range of environmental and soil conditions. Once established, lespedeza is very difficult to remove due to its persistent seed bank which can remain viable for years. To successfully control lespedeza, we must find effective ways to suppress or kill seeds in the soil, but this has received little research attention.
Table of Contents
CHAPTER I
INTRODUCTION
Overview of Invasive Plants in United States: Upper Midwest
Distribution and Occurrence of Invasive Plants in The Upper Midwest.
Ecological and Economic Impacts of Invasive Plants.
Restoration of Grassland in North America
Mowing
Herbicides
Distribution and Occurrence of Sericea Lespedeza in The United States
Botanical and Ecological Characteristics of Sericea Lespedeza
Plant morphology
Seed production /Seed banking
Seed dispersal
Germination
Ecological Impacts of Sericea Lespedeza
Study Questions / Objectives
CHAPTER II
METHODS
Study Areas
Soil Seed Bank Sampling
Greenhouse Seed Bank Procedure
Field Treatment Experiment
Data Analysis
CHAPTER III
RESULTS
Seed Bank
Effect of Pre-Emergent Herbicides on The Performance of Height and Stem Count of Indian Grass
Effect of Pre-Emergent Herbicide on The Emergence and Cover of Lespedeza Seedlings
CHAPTER IV
DISCUSSION
Research Objectives and Focus Areas
The primary research objective is to develop effective strategies for controlling the invasive plant Sericea lespedeza by managing its persistent soil seed bank and facilitating the successful establishment of native Sorghastrum nutans (Indian grass) in degraded grassland ecosystems.
- Characterization of the Sericea lespedeza soil seed bank density in various infested campus sites.
- Evaluation of pre-emergent herbicide efficacy in suppressing Sericea lespedeza germination post-eradication.
- Assessment of Indian grass growth performance under different management regimes.
- Investigation into the impact of mowing and herbivory on invasive population dynamics and native species recovery.
Auszug aus dem Buch
Botanical and Ecological Characteristics of Sericea Lespedeza
Lespedeza is an invasive, warm-season, short life cycle, perennial plant (Bare 1979). Plants are shrubby looking due to the many stems which develop with age. Plants height ranges 0.5 to 2 m (Bare 1979, Diggs et al. 1999). Leaves are dense and alternate along the branches and main stem (Gleason 1991). Leaflets are 1.5 to 6 mm in width and 0.5 to 2.5 cm in length (Bare 1979). Inflorescences are solitary or in a group of 2 to 4 in the axils of the top and middle leaves (Gleason 1991, Stubbendiek and Conad 1989). It either produces chasmogamous and/or cleistogamous flowers. Plants have indehiscent legume fruits which are single-seeded and 2.5 to 3.5 mm in length. Lespedeza seeds are usually 1.5 to 2.5 mm long (Stubbendiek and Conad 1989). Plants grow an extensive, woody taproot which can develop as large as 0.9 to 1.2 m deep into the soil (Czarapata 2005).
Summary of Chapters
CHAPTER I: Provides an overview of invasive plant issues in the U.S. Upper Midwest, detailing the characteristics and ecological impact of Sericea lespedeza and the challenges of grassland restoration.
CHAPTER II: Outlines the scientific methodology, including the seedling emergence method for seed bank assessment and the field treatment experiment involving herbicide application and native grass planting.
CHAPTER III: Presents the findings regarding seed bank variability across sites and the measured performance of Indian grass and lespedeza seedling emergence under experimental treatments.
CHAPTER IV: Discusses the implications of the results, specifically regarding the effectiveness of pre-emergent herbicides and the competitive dynamics between invasive lespedeza and native grassland species.
Keywords
Sericea lespedeza, Lespedeza cuneata, invasive plants, grassland restoration, soil seed bank, seedling emergence, Indian grass, Sorghastrum nutans, pre-emergent herbicide, Trifluralin, herbicide application, grassland ecology, weed management, species competition, biological invasions
Frequently Asked Questions
What is the central focus of this thesis?
The thesis investigates the control of the invasive plant Sericea lespedeza in North American grasslands, focusing on managing the persistent soil seed bank and replacing it with native Indian grass.
What are the primary themes discussed?
The work covers invasive plant biology, the ecological impacts of Sericea lespedeza, seed bank dynamics, methods of mechanical and chemical weed control, and strategies for native prairie restoration.
What is the core research goal?
The goal is to determine if a pre-emergent herbicide can effectively suppress Sericea lespedeza germination from the seed bank to allow for the successful establishment of native Indian grass.
Which scientific methods were employed?
The study used the seedling emergence method to quantify seed bank density and conducted a field experiment using pre-emergent herbicides combined with native grass transplantation, analyzed via statistical methods like ANOVA.
What topics are covered in the main body?
The main body examines the morphological characteristics of lespedeza, the impact of mowing and herbicides, field observations of native grass performance, and discussions on herbivory and competitive pressure.
Which keywords characterize this research?
Key terms include Sericea lespedeza, soil seed bank, pre-emergent herbicide, Indian grass, and grassland restoration.
Why did the study observe such a high variation in seed bank density?
The study attributes the 10-fold difference between sites largely to mis-timed mowing, which scattered developed seeds, highlighting how mechanical disturbance can inadvertently facilitate invasive spread.
What role did herbivory play in the study results?
Rodent herbivory caused the total mortality of transplanted native grasses at the Nature Preserve site, revealing that invasive thickets may alter local herbivory pressure on native species.
What was the conclusion regarding the use of pre-emergent herbicides?
While the herbicide had a significant effect on reducing lespedeza seedling cover, the actual reduction was relatively small, suggesting that multiple rounds of treatment may be necessary for effective long-term control.
- Citar trabajo
- Eric Ntiamoah (Autor), 2017, Invasive Plants. Restoration of Grasslands Invaded by Sericea Lespedeza, Múnich, GRIN Verlag, https://www.grin.com/document/517366
