Wednesday, June 9, 2010

*My Introduction*

My name is Johanna Andrews and I am a Biology major at Hofstra University with a concentration in Pre-Medicine and a minor in Chemistry. I will be a senior in the fall and I was awarded an undergraduate research fellowship in the Biology Department. After attaining my degree, I plan to go on to Medical School and pursue a career in Obstetrics and Gynecology. I have always had an interest in children and the miracle of life. Although, I have always loved medicine, the Biology program has exposed me to many disciplines in this major. As a result, my eyes have been opened to a world of new interests.

After taking introductory biology courses, I realized that I was very interested in the field of Ecology as well. I was amazed at the complexity and diversity of plants and I was very interested in doing a project that would broaden my knowledge in this field. Therefore, I began working with one of my biology professors, Dr. Myla Aronson, for my research experience. With her guidance, I was introduced to the invasive species Ranunculus ficaria. A biological invasion occurs any time an organism is introduced to a new area outside of its current range. These invasions are often linked with anthropogenic disturbance of the environment, but pristine natural habitats may also be susceptible to invasion (Meekins and McCarthy 1999). The phenomenon of biological invasions is a growing concern of scientists, nature preserve managers, and conservationists (Meekins and McCarthy 1999). One reason for studying invasions is that many invasive species have become serious pests. Due to the economic importance of invaders, it is important to realize how little we understand and how predictions of the outcome of new invasions can only be weak and reliable (Williamson 1996). Invasive species may negatively affect a community by leading to decreases in population numbers, increases in species extinctions, or alterations in ecosystem function. These effects may be achieved by many factors. These factors include competition, predation, diseases or amensalism (Meekins and McCarthy 1999).

One non-native invasive plant of recent concern in riparian and forested areas of the Northeast is Ranunculus ficaria, also known by its common name lesser celandine. While the invasion of R. ficaria has been well documented by land managers, this plant is not well-studied ecologically. It is not known exactly when this plant was introduced to the United States. This plant is currently found in nineteen states in the Northeast and Pacific Northwest. It is reported to be invasive in nine states including Connecticut, Delaware, Maryland, New Jersey, Oregon, Pennsylvania, Virginia, Wisconsin, West Virginia and in the District of Columbia (USDA Forest Service). The variety that is invasive in the US is Ranunculus ficaria var. bulbifera (Metcalfe 1938). This plant is an herbaceous, perennial plant in the buttercup family, Ranunculaceae. They have a basal rosette of dark green, shiny, stalked leaves that are kidney-shaped to heart-shaped. The flowers open in March and April, have 8-12 glossy, butter-yellow petals that are 1 inch wide, and are borne singly on delicate stalks that rise above the leaves. Along the stems of the above-ground portions of the plant, pale-colored bulblets are produced. However, these bulblets are not visible until late in the flowering period. The root system is composed of a cluster of tuberous roots and when in bloom, large infestations of R. ficaria appear as a green carpet with yellow dots, spreading across the forest flower. As a result of the plant’s production of many bulbils and tubers, it spreads rapidly across habitats as well as colonizes them when it grows and dies (USDA Forest Service).

The objective of my study is to examine the effects of R. ficaria on native forest herbaceous plants. It has been observed that after R. ficaria dies in the beginning of June, no other plants grow in the invaded areas. Due to the life history of late-blooming forest herbaceous plants, R. ficaria should not compete directly for space, water and nutrients. Therefore, I believe that R. ficaria may have allelopathic effects on native plants. I will be planting seeds of five native species in invaded areas and non-invaded areas as well as examining the growth and reproductive response of these native plants to R. ficaria invasion. These seeds will be planted in July after the R. ficaria plants die, thus indirectly examining possible allelopathic effects left in the soil.

Ranunculus ficaria is primarily a threat to native plants and native plant diversity in lowland woods and on flood plains. It outcompetes native plants through its extremely early seasonal growth and the development of a dense network of roots and tubers in the soil. Over time it forms extensive carpets in natural areas, crowding out native plants, especially native ephemeral wildflowers. There is little understanding of this plants ecological effect. After a thorough literature search, no published peer-reviewed studies were found on the effects of R. ficaria on native plants. Therefore, research on this species will help manage native plant conservation as well as understand other invasive species.

1 comment:

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