Ecosystems at Risk


HSC GEOGRAPHY 2004 – Assessment Task 2


Ecosystems at Risk


1. Identify the case study of the ecosystem at risk which you have chosen and describe and map its location.


The ecosystem at risk that I have chosen to research is the Himalayan Mountain range. Considering the mountain range covers a very large area, the ecosystem type has been narrowed down to the Alpine variety. The 2 500 kilometre long Himalayas stretch across three countries; India, Nepal and China (Tibet). The width of the mountain range varies from 100-400 kilometres, giving a total area of 594 400 square kilometres.


http://www.nationalgeographic.com/xpeditions/atlas/index.html?Parent=asia&Rootmap=nepal


2. Outline the main features of the functioning of this case study with particular reference to what makes this ecosystem vulnerable and/or resilient.


The alpine ecosystem of the Himalayas begins at about 3 000 metres above sea level. The sheer height of the Himalayas produce a number of different climate variations. On the southern slopes of the Himalayas in India, heavy rain and snowfall is received yearly, but the northern slopes of Tibet frequently remain untouched by rainfall. The taller mountains have temperatures that stay below zero degrees all year round, with permanent ice, snow and wind speeds that can reach up to 160 kilometres per hour. Temperature ranges in summer can reach a maximum of 12 degrees at 3 000 metres. Minimum temperatures are found higher up at around 5 000 metres, where the temperature rarely reaches above 0 degrees.


Due to the alpine conditions, the soil quality is very low in fertility due to the poor nutrient cycling. Without trees the biomass levels are lowered, meaning that there is hardly any decaying material that can adequately return nutrients to the soil. The poor soil quality can only support certain types of vegetation, this includes junipers, mosses and rhododendrons. Commonly these plants form meadows that can be found up to heights of 5 000 metres. Above this height, it is rare to see any vegetation as plants cannot survive in frost. The fragile nature of the nutrient cycle and energy transfer rates make the Himalayas very vulnerable to change.



Rhododendrons


http://www.trekkinginhimalayas.com/photo_gallery.cfm?pno=4


There are only a few carnivores that can survive above the tree line, for example the Snow Leopard, Himalayan Brown Bear, Red Panda and Tibetan Yak. Animals that habitat the area have adapted to the climatic conditions of the Himalayas. In Summer, animals migrate higher up to the grasslands, and in Winter they migrate lower for warmer temperatures. The Himalayan Black Bear hibernates, but unlike other bears, there is no set season since the weather is always at freezing point. Carnivores have also adapted to the smaller amount of food, making the carnivores proportionally smaller having to feed off small animals like rabbits. The primary consumers in the food chain is hugely vulnerable as the carnivores have a limited food supply in the high altitudes. Secondary consumers can survive above the tree line because of the vegetation that still grows up to 5 000 metres. This makes the herbivores resilient to change because the vegetation growth covers thousands of square kilometres and because the mosses, meadows and grasslands etc. have adapted to the alpine conditions.



Tibetan Yak


http://ananta.hypermart.net/NepalAlbumThree.htm


3. Explain the impacts of natural stress and human induced stress where possible include rates of change.


The characteristics of an alpine ecosystem make it exceptionally vulnerable to natural and human induced stress. The Himalayas are prone to a regular occurrence of natural disasters because the mountains lie directly on a fault between the Eurasian and Indian Australian tectonic plates. Being the home to the highest point on Earth, the Himalayas is unsurprisingly a popular tourist location. As a result humans have “taken control” of the area, and simultaneously destroying the ecosystem.


http://pubs.usgs.gov/gip/volc/fig37.gif


Earthquakes take an immediate effect on the Himalayas, triggering giant landslides. Large portions of rocks and boulders break off the mountain slope and travel towards the bottom, destroying large amounts of flora and fauna. Earthquakes also make the terrain unstable, rendering the area useless. Although glaciers are very tiny compared to what they were hundreds of years ago, they are still considerably significant in impacting the natural environment. Glaciers are a long-term major cause for mass amounts of erosion, where there is little vegetation cover in the alpine regions. The terminal moraine which gets left behind