Lichens of the Family Xanthoparmelia

Introduction:

The objective of the research is to shed some light on the ecological interaction between the foliose lichen, Xanthoparmelia tasmanica (Lepp, 2011) and the resources and organisms in its environment. This particular species has been observed to grow abundantly only on the south facing side of rocks in the southern hemisphere, this might suggest that relatively higher light intensity of north facing rocks is a factor that hinders its growth. However, without further testing, it cannot be stated with certainty that light is in fact correlated with growth of X. tasmanica, rather than other factors such as wind, humidity and interactions with other organisms.

Description:

To ensure sufficient sample size, at least 60 samples of X. tasmanica thalli growing on the same type of substrate are to be collected (Benedict 1990). Half of the sample are to be kept in an enclosed and controlled environment as the control group. This group will be exposed to favourable conditions for growth (favourable light intensity, humidity, wind, and nutrient level) in an isolated environment away from disturbances (Gentner 1967; Wiley et al. 1982). The rest of the sample will be kept in a separate controlled environment identical to the control group with the exception of the level of light intensity present. This second group will be exposed to a higher level of light intensity mimicking what it would have experienced if exposed to direct sunlight. Periodic measurements at monthly intervals will be conducted (Armstrong 1973). These measurements will be recorded over a 2 year period and will include starting diameter, number of lobes, and mean radial growth rate. Statistical analysis will be conducted to infer characteristics of the population based on the measured sample data. If the second group exhibits similar growth rate compared with the control group, the hypothesis would be refuted