Individual report:vegetation succession on lava flows - Essay Example

Download file to see previous pages... Volcanic lava flows occurred in these areas and are referred to as primary succession. All organic matter and soil has disappeared, however, some of the sites visited have experienced secondary succession, as soil and organic matter grew in the area. One major goal was to see if the vegetation followed Gleason or Clements theory, where by vegetation succession occurs at random. Clements’ theory stated that the pioneering species change the environment, allowing new species to develop as they cannot develop in the pioneering conditions known as facilitation. The activity aimed to see if in the older environments, the pioneering species had allowed for new growth and, in the newer environments, what the pioneering species are. This is what is known as vegetation succession. Gleason’s view is supported by Whittaker in believing species respond to changes individually. Vegetation succession has 6 stages; nudation area left bare, migration-species arrive, Ecesis plant seeds establish themselves, competition-plants compete with one another for resources, reaction-established plants alter the environment, and stabilisation-equilibrium reached. This could be seen to an extent on older sites, rather than in the newer areas of volcanic ash, as the pioneering species such as lichens and mosses had a lower percentage of cover compared to forbes and grasses. However, it is hard to verify what stage it is in as we don’t know if any new species have or will occur in succession. With increased altitude comes decreased sunlight and increased precipitiation. Durbin (1981) has stated that areas within the region piedmontese have been replaced with commercial production. I don’t believe the areas we were in exhibited this as we visited only one part considered in regionee piedmontese. See handbook lit for this. Finlay 1968 and King 1973 stated that the regione boscara would ‘have been engulfed by lava flows’. This was evident at site number 2, from the 1910 and 1983 lava flows, as lava flows were predominant with bits of lichens and mosses growing. Which followed what Clements seems to suggest as; initial communities are dominated by mosses, then by more diverse species. ‘The soil of Sicily is for the most part remarkably rich and fertile, and consists of a great variety of earth’s’. page 12 (http://books.google.co.uk/books?id=3MsZAAAAYAAJ&printsec=frontcover&dq=sicily+vegetation&source=bl&ots=smASoAa18i&sig=Kq7maeTAIMMQzqEax2HwbiHq_nE&hl=en&ei=GnaoTYCBLcio8AOW2Y2nBg&sa=X&oi=book_result&ct=result&resnum=4&ved=0CCYQ6AEwAw#v=onepage&q&f=false http://books.google.co.uk/books?id=tdLAbiExrHcC&printsec=frontcover&dq=fundamentals+of+biogeography&hl=en&ei=sl2cTZCUCdO08QPEh6DmBg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CDMQ6AEwAA#v=onepage&q&f=false page 225 Within Etna there are 3 vegetation zones; the regione piedmontese (sea level-1000m) Site 1669 (Nicolosi), regione boscara (1000-2000m), (Sites 1910 and 1983) and regione deserta (>2000m). Clearing activity has led less natural successional communities and the development of maquis (schrubland vegetation) and garigue (sparse vegetation). (Chester 1985) Over time there should be a greater amount of vegetation and the objective of ...Download file to see next pagesRead More