Orthocladius Essay

By comparing the data in Table 2 against the graph above, it is discovered that Site 1 is located on the St Mary’s glacial river and feeds onto the meltwater from the St Mary’s glacier. Orthocladius is most abundant between 2 and 4 degrees as well as Microspectra. The first 2 bugs thrive when it is 2 to 4 degrees and they are most rich at site 1. At site 2, Psectrocladius is present between 6 and 8 degrees. Site 2 is situated on St Mary’s River at a height of 1100m and is located approximately 10km east of site 4. Reasons for the cooler temperatures than sites 4 and 3 is the glacial meltwater that sources the river causing significantly lower water temperatures, but also the higher temperature compared to site 1 may be caused by the willow and birch scrub cover, lower altitude and the water load from the warmer non-glacial tributaries.
At site 3 and 4, Tanytarsus is most abundant between 12 -14 degrees. Site 3 is nearer the Elphistone River source which channels from the Westerly catchment area away from the St Mary’s glacier. This site is situated at a height of 1200m and has half the abundance of Tanytarsus organism. It can be concluded from the habitat preference curve that the likely temperature of the river at Site 3 would be 11o C.
Site 4 is situated at a height of 1000m on the non-glacial Elphistone River with …show more content…
In addition, there has been a reduction in the Willow/Birch scrub cover. Figure 3 (in the question booklet) demonstrated a simplified stratigraphic profile. This shows the gravel rich sediments have increased in site 1 and 3 and a small amount of sediment in 2 and 4, meaning that erosion has increased from the glacier and river transport leading to a gravel rich sediment. Furthermore, there was reduced land coverage by birch/willow scrub cover from the smaller organic sediment