Sample Report Paper on Examining the Effects of Land Use on Species Diversity: The Composition of Ants in Forest, Edge and Pasture Habitat

The land is arguably one of the most important natural resources that aid in the sustenance of the economy. Human beings use land in various economic activities, including food production, livestock rearing, and timber and energy production, among others. Carrying out these activities while still maintaining ecosystem balance and diversity has, according to scientists, been a great environmental challenge in the modern time (Yeo et al., 2011). Yeo and others illustrate how diversified changes in land usage results in decrease of plant and animal species (2011). This is because some of the species are adapted to a particular set of conditions and may not survive when the conditions are interrupted. In a study by Boulton and others (2005), species composition was found to change with increased agricultural productivity. According to Boulton et al.’s research, for instance, prolonged and intense grazing results in decline of species (2005). Various studies have indicated that land usage interferes with species diversity, but how does changes in land use affects the composition and species richness of ants? This study examines the composition of ants in forest, edge and pasture habitats of Samford Valley in Australia.

Materials

The experiment uses six Petri dishes, sugar, protein, flagging tape, pipettes, paint brushes and ethanol.

Method

The site of the experiment, the Samford Valley, is characterized by subtropical climate and hosts myriad of plant and animal species. Over the years, the Samford Valley has been grazed, burnt and slashed. This experiment evaluates whether the composition of ants at the site relates to the historical changes in land usage. For the purpose of this study, the site was classified into three sub-habitats. The first part includes the grazed but not slashed part, named as the forest. The second part covers the grazed and slashed region, which was categorized as the pasture while the last sub-habitat, the edge, composed the most vulnerable habitat along the edges. It is hypothesized that the difference in prior land use altered the composition of ant species.

The experiment was carried by fourteen different groups, each with members. Two Petri dishes, one filled with sugar syrup and the other with protein syrup, were placed in each of the three sub-habitats. These syrups filled Petri dishes were to serve as a trapping component for the ants as they gather for feeds. The exact location of the trapping dishes was marked using the flagging tape for ease of identification. The dishes remained at the respective sites for thirty minutes, enough time for ants to recruit to the food sources. While the ants wrestled for food at the Petri dishes, each of the five group members spent 10 minutes searching and collecting ants from the ground, shrubs and trees in each habitat using the paintbrush and/or pipette. The collected ants were preserved into an ethanol filled collection tube, ready for further analysis.

The analysis involved the sorting of ants into different morphospecies where dissimilar species were identified and tallied to estimate the species richness. The results in each sub-habitat were compared against other sub-habitats.

Results and Statistical Analysis

Every group recorded the number of species obtained per site. A total of 10 different species were collected. The following is a presentation of the species richness as obtained in this experiment.

 

Table 1; Species Richness across sites

Chart 1; Species Richness

As indicated in table 1, the mean number of species reported in forest habitat (mean of 6) is higher than that of edge and pasture habitat (mean of 4.4 in both habitats). Nonetheless, is the difference statistically significant? This was determined using the ANOVA single factor test in Table 2 below. According to the test, F=1.047 with a critical value of 0.05, the critical F=3.98, that is F statistics is less than the critical value. Further, the P value=0.38, which is greater than 0.05 and thus, the null hypothesis is not rejected. Therefore, there is no significant difference in species richness across sites.

Table 2; ANOVA Single test: Null hypothesis: there is No difference in species richness across site composition. Reject the null hypothesis if p<0.05

In addition to the ANOVA test of similarity, species composition was also analyzed using the Jaccard coefficient that compares between two sets of data. In this experiment, the Jaccard similarity is the ratio of the number of species widespread to any two give sites (C) and the total sum of species present in both sites (S).

Jaccard Similarity=C/S

Table 3 shows different morphospecies and the sites in which the each species was present. It also illustrates the computation of the Jaccard similarity. The Jaccard Similarity values were expected to range from zero, when no species is common to both sites and one when all species are found in both sites. As observed in this experiment, the JS values are all more than 0.5. Hence, more that 50% of species were common in the compared sites.

Table 3; Species composition across sites

Discussion

The forest, pasture and edge habitat were historically subjected to different levels of land usage. The expectation was that the difference in land use would have affected the ant species richness. However, the experimental results did not show a material difference in ant species variety. This may be because other factors that affect ant species presence that were not examined in this experiment might have been the same in all the habitats. For example, ant species richness has been found to correlate with plants species richness and density (Grau et al., 2005). The difference between forest and pasture habitat is that the earlier was grazed but not slashed while the latter was grazed and slashed. However, there may not be a significant change in plant vegetation as a result of slashing since plants may re-grow after the slash. On the other hand, the edge habitat was presumed to be vulnerable to disturbances and abiotic influences; nevertheless, this was not evident in ant species richness.

Although this survey was successful, there are various biotic and abiotic factors that might have influenced the results. For instance, light and temperature ambient are among the factors that have been found to affect ant’s activities (Jayatilaka et al., 2011, Navendra et al., 2013). According to a study by Jayatilaka and others, for example, temperature affects the rate of decay of the trail, thus altering the rate of ant recruitment (2011). Also, some ant species are nocturnal and some are diurnal. Others are only active during the morning and evening twilight. This experiment may be improved by considering the biological characteristics that differentiate the various habitats such as plant species composition.

References

Boulton, A. M., Davies, K. F., & Ward, P. S. (2005). Species richness, abundance, and composition of ground-dwelling ants in northern California grasslands: role of plants, soil, and grazing. Environmental entomology,

Grau, H. R., Aide, T. M., Zimmerman, J. K., Thomlinson, J. R., Helmer, E., & Zou, X. (2003). The ecological consequences of socioeconomic and land-use changes in postagriculture Puerto Rico.

Jayatilaka, P., Narendra, A., Reid, S. F., Cooper, P., & Zeil, J. (2011). Different effects of temperature on foraging activity schedules in sympatric Myrmecia ants.

Narendra, A., Reid, S. F., & Raderschall, C. A. (2013). Navigational efficiency of nocturnal Myrmecia ants suffers at low light levels. PloS one,

Yeo, K., Konate, S., Tiho, S., & Camara, S. K. (2011). Impacts of land use types on ant communities in a tropical forest margin (Oumé–Côte d’Ivoire). African Journal of Agricultural Resear