solved Assess the impact of declining biodiversity upon a major terrestrial

Assess the impact of declining biodiversity upon a major terrestrial biome that you
have studied.Mark schemeLevel 3 (7–9 marks)AO1 – Demonstrates detailed knowledge and understanding of concepts,processes, interactions and change. These underpin the responsethroughout.AO2 – Applies knowledge and understanding appropriately with detail.Connections and relationships between different aspects of study arefully developed with complete relevance. Evaluation is detailed and wellsupported with appropriate evidence.Level 2 (4–6 marks)AO1 – Demonstrates clear knowledge and understanding of concepts,processes, interactions and change. These are mostly relevant thoughthere may be some minor inaccuracy.AO2 – Applies clear knowledge and understanding appropriately.Connections and relationships between different aspects of study areevident with some relevance. Evaluation is evident and supported withclear and appropriate evidence.Level 1 (1–3 marks)AO1 – Demonstrates basic knowledge and understanding of concepts,processes, interactions and change. This offers limited relevance withinaccuracy.AO2 – Applies limited knowledge and understanding. Connections andrelationships between different aspects of study are basic with limitedrelevance. Evaluation is basic and supported with limited appropriateevidence.Notes for answersAO1 The concept of the biome. The global distribution of major terrestrialbiomes. The nature of one biome: tropical rainforest or savanna grassland toinclude: the main characteristics of each biome; ecological responsesto the climate, soil and soil moisture budget – adaptations by flora andfauna; human activity and its impact on each biome; typicaldevelopment issues in each biome to include changes in population,economic development, agricultural extension and intensification,implications for biodiversity and sustainability.The concept of biodiversity. Local and global trends in biodiversity.Causes, rates and potential impacts of declining biodiversity.AO2 Responses are likely to consider either tropical rainforest or savannagrassland. Other biomes may be considered such as temperatedeciduous woodland or tundra for example. The loss of biodiversity has many potential consequences. Losses in biodiversity in rainforests cause significant changes inecosystem functioning. The particular species making up anecosystem determine its productivity, they affect nutrient cycles andsoil constituents, and they influence environmental conditions such aswater cycles, weather patterns, climate and other abiotic aspects suchas soil formation. Some may argue that in some ecosystems it is possible that manyspecies can disappear without serious degradation of most of thefunctional aspects of the ecosystem. Many ecologists nevertheless feelthat the total number of species has a great effect on ecosystemfunctioning. Reducing biodiversity may lead to a reduction inproductivity because of the loss of some niche roles. Reduced biodiversity affects soil processes, decomposition, waterretention and many other ecosystem functions. For example increasingthe diversity of plants, herbivores, and decomposing organisms, mayincrease net primary productivity (NPP). Areas with greater numbers ofspecies tend to have a greater above- and below-ground plantbiomass, higher rates of nitrogen fixation. Data suggests for a 50%reduction in biodiversity, there will be a 10%–20% loss of productivity.There are suggestions that loss of species richness may affect manyecosystem processes (nutrient cycling, increased uptake of carbon,and others) in addition to productivity. Another unintended impact of reduced biodiversity relates to firehazards and wider impact upon local climate. In Hawaii for example,grasses were introduced to improve cattle grazing, but since thesegrasses are flammable, they have caused a significant increase in firesin the forests into which they spread. Most woody plants are damagedor destroyed by fires, while grasses generally are not, since their deeproot systems are maintained even when the superficial portions of theplant are lost. This in turn reduces evapotranspiration and rainfall. Iftropical forest trees are removed and their place is taken by savannahgrasses, the evapotranspiration is reduced, decreasing rainfall (andreducing the possibility of forest regeneration). Trophic interactions may be altered as biodiversity declines:Ecosystem functions depend greatly upon trophic interactions amongspecies within that system. For instance, if carnivores are removed,prey species populations may grow tremendously, leading to a seriesof uncontrolled changes in the system.Credit any other valid approach. Evaluation should be based uponpreceding content.