Biology in the Real World

Introduction

An ecological system is often characterised by biodiversity meaning a wide range of biological species both plants and animals coexist together. However, during interspecific competition one species may significantly reduce the population of the other leading to disruption of the previously existing ecosystem (Leveque & Mounolou, 2003). For instance, an ecological research in old-growth forests in Wisconsin reveals that Pennsylvania sedge, a grass-like species dominates the forest floor. This may be due to the exclusion of other ground species by sedge through interspecific competition, which may lead to a decrease in the forest’s biodiversity. The other issue which may be attributable to the observable ecological behaviour in the Wisconsin forest may be selective herbivory due to the white-tailed dear abundance leading to a significant reduction of most other ground plants (Margulis et al., 2009). Moreover, another problem is that the dominant trees in the forest including white pine and sugar marple are not successfully reproduced to perfectly reproduce old pines and maples that die.

As a result of this an ecological research was carried out to collect data on the ground vegetation cover using transects and quadrants across the study plot at Trout Lake Cathedral Point, Vilas County, Wisconsin and the obtained numbers were recorded. However, this ecological research sought to test the three proposed hypotheses which are:

Pennsylvania sedge inhibits regeneration of white pine
Pennsylvania sedge inhibits regeneration of sugar maple
Pennsylvania sedge decreases biodiversity

Data analysis

The results of this ecological research are presented in both tables and graphs in order to ensure that the hypotheses are effectively tested to enables discussion of the results to be carried out as well as conclusion and recommendations to be made (Margulis et al., 2009). In particular the results section is divided into four sections where the first section presents a table of the overall results, while the subsequent sections two, three and four each present the results of each research hypothesis.

Table 1: A table of overall research results

Pennsylvania sedge cover percentage	Quadrants	Number of white pine	Number of sugar maple	Number of species
0-25	133	85	86	676
26-50	13	8	1	63
51-75	15	15	3	84
76-100	28	16	5	136
Totals	189	124	95	959

The results shown in the above table show that as the percentage cover of Pennsylvania sedge continues to increase there is a significant decrease in the overall vegetation including the number of white pine, sugar maple as well as the total number of species. This also indicates a decrease in biodiversity (Margulis et al., 2009).

The subsequent results in section two through four are presented both in terms of tables and graphs where the tables shows the grouped results of the quadrants and a graph to determine the relationship between the independent variable (Pennsylvania sedge) and dependent variables (number of white pine, number of sugar maple and number of species).

Pennsylvania sedge inhibits regeneration of white pine

Table 2: A table of the results between Pennsylvania sedge percentage and the number of white pine

Pennsylvania sedge cover percentage	Quadrants	Number of white pine
0-25	133	85
26-50	13	8
51-75	15	15
76-100	28	16
Totals	189	124

Graph 1: A graph of the relationship between Pennsylvania sedge percentage and the number of white pine

The results shown above in Table 2 and Figure 1 show that Pennsylvania sedge inhibits regeneration of white pine because as the Pennsylvania sedge cover percentage increases there is a significant decrease in the number of white pine seedlings in the forest. Therefore, the results shown in the above table and chart indicate that Pennsylvania sedge inhibits regeneration of white pine.

Pennsylvania sedge inhibits regeneration of sugar maple

Table 3: A table of the results between Pennsylvania sedge percentage and the number of sugar maple

Pennsylvania sedge cover percentage	Quadrants	Number of sugar maple
0-25	133	86
26-50	13	1
51-75	15	3
76-100	28	5
Totals	189	95

Graph 2: A graph of the relationship between Pennsylvania sedge percentage and the number of sugar maple

The results shown above in Table 3 and Figure 2 are show Pennsylvania sedge inhibits regeneration of sugar maple because as the Pennsylvania sedge cover percentage increases there is a significant decrease in the number of sugar maple seedlings in the forest. Therefore, the results shown in the table and charts indicate that Pennsylvania sedge inhibits regeneration of sugar maple.

Pennsylvania sedge decreases biodiversity

Table 4: A table of the results between Pennsylvania sedge percentage and the number of species

Pennsylvania sedge cover percentage	Quadrants	Number of species
0-25	133	676
26-50	13	63
51-75	15	84
76-100	28	136
Totals	189	959

Graph 3: A graph of the relationship between Pennsylvania sedge percentage and the number of species

The above results shown it Table 4 and Figure 3 are indicative of the fact that there is a significant decrease in the number of biodiversity which shows a low number of species richness. Therefore, both the results shown in the table and charts indicate that Pennsylvania sedge decreases biodiversity because as the percentage cover of Pennsylvania sedge is increased, the number of species decreases significantly.

Discussion and conclusion

From the results presented in the above section, it is clearly evident that the three hypotheses that were proposed at the beginning of this ecological research are all supported. Therefore, hypothesis A through C are all supported through the data analysis which show a decreasing number of the white pine, sugar maple and the number of species with increasing percentage of Pennsylvania sedge cover. However, shade which influences the number of light reaching the ground vegetation may also play a crucial role in making sure that the population of other species do not thrive, but this must also be accompanied by the adaptation of Pennsylvania sedge to thrive in limited amount of light (Leveque & Mounolou, 2003). Moreover, since the forest also consists of many herbivores, the observed change may also be attributed to selective herbivory by the animals that inhabit this forest which means specific specifies may continue to decrease because they are often fed on creating more space and nutrients for the Pennsylvania sedge to continuously growth due to reduced competition. This may cause other two hypotheses to be proposed which state that: (1) Shade influences the biodiversity of old-growth forests in Wisconsin; and (2) Selective herbivory cause inhibition of other species as Pennsylvania sedge continues to thrive at old-growth forests in Wisconsin.

In conclusion, it is undoubtedly evident that Pennsylvania sedge leads to an overall inhibition of other species in the considered ecosystem because as its percentage cover increases the number of other species continue to decreases an indication that it also decreases biodiversity which is confirmed by a decrease in the number of species observed in quadrants where its percentage cover was significant.

References

Holling, C. S. (1973). Resilience and stability of ecological systems. Annual Review of Ecology and Systematics, 4(1), 1–23.

Levin, S. (2010). Encyclopedia of Biodiversity. San Diego: Elsevier Academic Press.

Leveque, C. & Mounolou, J. (2003). Biodiversity. New York: John Wiley and Sons Inc.

Margulis, L., Dolan, Delisle, K., Lyons, C. (2009). Diversity of Life: The Illustrated Guide to the Five Kingdoms. Sudbury: Jones & Bartlett Publishers.

Novacek, M.J. (ed.) (2001). The Biodiversity Crisis: Losing What Counts. New York: American Museum of Natural History Books.

Pereira, H.M., Navarro, L.M. & Martins, I. S. S. (2012). Global Biodiversity Change: The Bad, the Good, and the Unknown. Annual Review of Environment and Resources, 37(2), 25-38.