Widener University Journal of Undergraduate Ecological Research

Widener University Journal of
Undergraduate
Ecological Research

    The research inquiry journal for the course
         Biology 301, Introduction to Ecology.

         Volume 7, Number 2, Fall 1999

         Dr. Bruce W. Grant, Editor
         Department of Biology,
         Widener University , Chester, PA, 19013.
         office Kirk. 200, 610-499-4017.
         grant@pop1.science.widener.edu

Please Read This Comment.

       The abstracts at this site were written by junior or senior undergraduates and are the culmination of semester long ecological research inquiries that are a core component of my ecology course at Widener University. These students are biology, environmental science, or science education majors and minors.

       These abstracts (and the manuscripts to which they refer) have been peer reviewed by other students in the class according to specific guidelines I have generated for format, clarity, and the student reviewers' assessment of the scientific merit of their peer's manuscript.

       It is important for interested visitors of this site to understand that the results of the research inquiries reported in this journal are the results of course projects designed, conducted, and reviewed by undergraduate students in an ecology course.

       You are welcome to download some or all of the material I have posted at this site for your use in your ecology course. This does not include commercial uses for profit. If you do use any lengthy exerpts (more than 2 lines) of the material above, I request that you formally acknowledge this site and/or sites I have acknowledged as the source(s). I also request that you reciprocate and send me a copy of your ecology materials so that I may see what you have put together.

Please send comments to me: grant@pop1.science.widener.edu.

Volume 7, Number 2, Biology 301, Fall 1999.

1. The Effects of Exotic Ornamentals on Understory Plant Biodiversity in the Duer Tract, Nether Providence Township, PA. Elaine Crescenzi, Mary Malosh, and Shannon McGlinchey.

2. The Search for Nothing: The Effects of Hurricane Floyd on Macroinvertebrate Species Population and Biodiversity in Crum Creek, Southeastern PA. Robert Dendall, Jennifer Fuchs, and David LeBold.

3. Among-site Variation in Periphyton Abundance and Biodiversity Along Crum Creek in Southeastern PA: Is "Exceptional Value" Status Justified for the Upper Crum Creek? Corinne Piotrowski, Aaron Stillwell, and Mayerling Thanis.

The Effects of Exotic Ornamentals on Understory Plant Biodiversity in the Duer Tract, Nether Providence Township, PA. Elaine Crescenzi, Mary Malosh, and Shannon McGlinchey.

ABSTRACT:
Exotic ornamental plants can have a serious impact on our environment and the economy. They have decreased biodiversity and caused billions in economic losses. We investigated the effects of exotic ornamental plants on the biodiversity in the Duer Tract located in Nether Providence, Delaware County, PA. There was a mansion and several outbuildings formerly located on this property and from a previous environmental study we understand that the landscape was very diverse, containing both exotic and native ornamental plants. However, the mansion and the outbuildings were destroyed by fire and abandoned over thirty years ago. Consequently, the landscaping was no longer maintained which facilitated the unabated growth of the exotic ornamental plants. Therefore, we hypothesized that the diversity would increase as the distance from the remnants of the former house increased because the exotic invasive ornamentals displaced the native ornamentals. Plant specimens were collected at different distances from the house using a point-intercept sampling scheme. The collection sites were recorded and a representative specimen of each species was preserved. The number of different species and their frequencies were counted. The Shannon Diversity Index (H') and the Kolmogorov-Smirnov statistical tests were performed. The exp(H') for the samples near the house was 1.98 and for the samples distant from the house it was 6.68. In the Kolmorgorov-Smirnov test we calculated a Dmax value of 0.51 which is significantly greater than the Dcrit(0.01) of 0.28. Both tests support our hypothesis that biodiversity increased with distance. To prevent further degradation by the exotic ornamentals, a study of various restoration methods, including physical removal of the exotics and introduction of native species, could be performed.

The Search for Nothing: The Effects of Hurricane Floyd on Macroinvertebrate Species Population and Biodiversity in Crum Creek, Southeastern PA. Robert Dendall, Jennifer Fuchs, and David LeBold.

ABSTRACT:
The diverse and numerous macroinvertebrate communities are among the most important components of ecosystems. A decline in biodiversity and number of macroinvertebrates would create an imbalance in the ecosystem in which they live. Our study looks at the effect of a natural disturbance, Hurricane Floyd, which caused major flooding in southeastern PA in September 1999, on macroinvertebrate species population and biodiversity. To understand just how Hurricane Floyd affected macroinvertebrates, we sampled four creeks in Delaware County, PA: Crum, Chester, Ridley, and Darby. We then compared our data to that collected in previous years. Methods included obtaining two aquatic kick net samples at each site, measuring water temperature and speed, testing for water dissolved oxygen levels, and comparing this data to data obtained before the hurricane. Data analysis consisted of comparative data species plots, Shannon Biodiversity Index calculations and plots, cumulative rank plots, and the Kolmogorov-Smirnov statistics plot. It was suspected that the hurricane would prove fatal to certain macroinvertebrate individuals. Therefore, population number and biodiversity would decline. Our results in comparison to data from before this disturbance indicate that species population densities declined and biodiversities increased after Hurricane Floyd. These results were partially consistent with our hypothesis. The diminished population size of every species (507 total number of organisms in the four old data sites compared to 88 in the creeks after the hurricane) coincides with the proposed effects of Hurricane Floyd. Contrary to our hypothesis, however, our biodiversities (old/new for Crum: 1.62/10.60, Chester: 2.37/4.86, Ridley: 1.14/1.83, and Darby: 2.06/7.21) were higher than expected. Nonetheless we still conclude that Hurricane Floyd did have an ecological impact on macroinvertebrates because the observed increase in diversity was due to the great reduction in numbers of what were previously numerically dominant taxa. In other words, the dominant taxa appear to have been most heavily impacted by the flood disturbance event. Further research studies relating to disturbance effects would aid in the support of hurricane effects on macroinvertebrate species population sizes and biodiversity. A study preceding a natural disruption would be helpful in assessing macroinvertebrate ability to reestablish. A post-hurricane study could again be compared and effects noted. Exact species observations could be noted for before and after a hurricane and the recovery rates of certain species could be tested.

Among-site Variation in Periphyton Abundance and Biodiversity Along Crum Creek in Southeastern PA: Is "Exceptional Value" Status Justified for the Upper Crum Creek? Corinne Piotrowski, Aaron Stillwell, and Mayerling Thanis.

ABSTRACT:
The stress levels in an aquatic environment affects species abundance, diversity and distribution. A petition is currently pending to the State of Pennsylvania to designate the upstream portion of Crum Creek (above the Springton Lake Reservoir) as of Exceptional Value (EV). Creeks granted EV status must support a non-impaired, high quality aquatic community (EPA website), however, the majority of indices used in making this designation are based on water quality, macro-invertebrates, and vertebrate communities. Little attention is paid to the essential organisms at the base of the food web – the periphytic (surface dwelling) phytoplankton. Therefore, we investigated the biodiversity of periphyton in Crum Creek upstream within the area under petition for EV status (assumed to be low stress) and downstream of the area petitioned for EV status (assumed to be high stress). We hypothesized that the periphyton diversity would be higher in the upstream area than in the downstream area because of the lower environmental stresses on these Creek ecosystems within the area under petition for EV status. We chose 5 sites along the creek, and we sampled periphyton from three rocks at each site. All rocks were submerged with slow current, direct sunlight, and shallow water. The algal samples obtained were mounted on slides, photographed, and censused. Among the five sites, we found 3830 total individuals that we classified into 40 different algal morphotypes. The number of different morphotypes found in each area varied greatly. Interestingly, according to Shannon Diversity indices, periphyton morphotypic diversity did not differ between upstream and downstream sites, which rejected our hypothesis. However, there were differences in which types of periphytom were common among sites, and the algal population densities were generally lower downstream. Future studies should focus on more intensive sampling of the slides and taxonomic identification of the periphyton species to look for pollution indicator taxa (especially among the cyanobacteria). In addition, future studies could involve free-floating microorganisms and chemical tests of water quality.