Succession and climatic climax

Outline the concept of climatic climax.

Figure 11 is in the insert.

Figure 11 shows the amount of organic carbon stored in different parts of various world biomes.

Analyse the data shown in Figure 11.

Figure 12 is in the insert.

Figure 12 shows the nutrient cycle in a typical temperate deciduous woodland.

Using Figure 12 and your own knowledge, assess impacts of human activity on the cycling of nutrients in a temperate deciduous woodland.

Assess the potential impact of climate change upon people living in savanna grasslands.

With reference to a coral reef that you have studied, assess the sustainability of human activity within the area.

Outline processes involved in mineral nutrient cycling in an ecosystem.

Figure 11 is in the insert.

Figure 11 shows information about global biodiversity by species category measured in 2019.

Analyse the information shown in Figure 11.

Figure 12 is in the insert.

Figure 12 shows a food web diagram of a coastal lagoon in Italy.

Using Figure 12 and your own knowledge, assess the potential impact of human activity on this food web.

How far do you agree that changes to the carbon cycle are leading to an increasingly uncertain future for coral reefs?

With reference to one plagioclimax in the British Isles, assess the factors affecting change and development in this ecosystem.

Outline the concept of climatic climax in vegetation succession.

Figure 11a and Figure 11b are in the insert.

Figure 11a shows the cause of deforestation in equatorial west Africa, 2000–2014.

Figure 11b shows national estimates of forest loss by area and cause in equatorial west Africa, 2000–2014.

Analyse the data shown in Figure 11a and Figure 11b.

Figure 12 is in the insert.

Figure 12 shows a range of issues facing game parks and reserves in Kenya, east Africa.

Using Figure 12 and your own knowledge, assess the implications of this data for sustainability in areas of savanna grassland in east Africa.

Analyse the interconnections between climate, vegetation and soils in the development of temperate deciduous woodland.

With reference to an ecosystem at a local scale, evaluate the extent to which management has created a viable future for the area.

Outline the effect of human activity on succession in one plagioclimax that you have studied (eg heather moorland).

Figure 11 is in the insert.

Figure 11 shows selected climate extremes and impacts affecting coral and forests in tropical and sub-tropical regions.

Analyse the data shown in Figure 11.

Figure 12 is in the insert.

Figure 12 shows information about coral reefs.

Using Figure 12 and your own knowledge, assess the implications of this information for the management of coral reefs.

How far do you agree that global governance has a role to play in the conservation of the savanna grassland biome?

With reference to the tropical rainforest biome, assess the view that latitude is the most important factor in its natural development.

Outline the process of succession in a lithosere.

Figures 11a and 11b are in the insert.

Figure 11a shows the global human footprint in 2009.

Figure 11b shows the change in the global human footprint between 1993 and 2009.

Analyse the data shown in Figure 11a and Figure 11b.

Figures 12a, 12b and 12c are in the insert.

Figure 12a shows coral bleaching in the Great Barrier Reef (GBR), Australia, in 2016.

Figure 12b shows estimated change in sea water pH caused by human-created CO₂ between the 1700s and the 1990s.

Figure 12c shows the sea surface temperature anomaly for the Coral Sea, Australia, between 1900 and 2016.

Using Figures 12a, 12b, 12c and your own knowledge, assess the scale of the threat facing this coral reef.

Assess the impact of declining biodiversity upon a major terrestrial biome that you have studied.

With reference to a region experiencing ecological change, assess the role of human activity in securing a sustainable future.

What is a seral stage?

A This is a stage where human activity has led to the creation of a sub-climax within the ecosystem. Until the human activity ceases the seral stage will remain.

B This is a stage whereby no further changes will occur in the succession. The only change that will occur is due to human activity or as a response to environmental change.

C This is a stage in the development of the ecosystem as it progresses towards climax. New species which are better adapted to the conditions outcompete a declining species.

D This is a stage in the food web. For example, primary consumers feed off the producers. This would be the second seral stage in the development of the food web.

What is the distinction between the biotic and abiotic components of an ecosystem?

A Biotic elements are the weathered rock and leaf litter. These elements interact with the organisms, heat and light (abiotic) to help produce a soil structure.

B Biotic elements are part of the structure of a food chain. The biotic elements provide the building blocks of life. The abiotic elements feed off the biotic elements in the food chain.

C Biotic elements are responsible for processes such as leaching and decomposition. Abiotic elements provide the raw materials (such as water) which allow life to flourish.

D Biotic elements are the living part of an ecosystem such as micro-organisms, plants and animals. Life is supported by the abiotic elements such as weathered rock, climate and various gases.

What are trophic levels?

A These are stages of a food chain or food web. At each new stage there are species which take energy from those in the previous stage. This process supports life.

B This is a stage in succession of plants in an ecosystem. At each new stage a better adapted species will dominate the local environment as it claims a niche in the local conditions.

C Trophic levels are a type of species which is responsible for the decay process in the ecosystem. These detritivores consume the dead matter and create conditions for regrowth.

D Trophic levels are a measure of the biodiversity within an ecosystem. An ecosystem with high trophic levels is considered to be healthy and free from human interference.

Why is weathering important in nutrient cycling?

A Weathering allows for eroded material to be carried away by aeolian processes. As the eroded material settles in new locations, plant colonisation begins, eg sand dunes.

B Weathering releases important minerals which decomposers further break down. Bacteria and fungi break down rock particles for future uptake by plants in the cycle.

C The weathered material is a key part of decomposition. Climate directly impacts upon leaf litter to aid the decomposition process. From this nutrients are released.

D Weathering processes are essential in the development of healthy soils. Weathered materials are mixed with biotic matter and become available for uptake by plants.

Figures 11a and 11b are in the insert.

Figure 11a shows rainfall totals and cumulative rainfall in a woodland savanna (cerrado) in south-east Brazil between 2009 and 2012.

Figure 11b shows the relationship between albedo and soil water content over the same time period for the same area.

Analyse the data shown in Figure 11a and Figure 11b.

Figures 12a and 12b are in the insert.

Figure 12a shows a simplified diagram of vegetation succession in moorland environments in the UK.

Figure 12b shows a moorland landscape in the UK.

Using Figure 12a, Figure 12b and your own knowledge, assess the potential role of human activity as an arresting factor shaping this landscape.

Evaluate the impact of human activity upon the future prospects for coral reefs.

‘Changing attitudes towards sustainable tourism, recreation and conservation have meant that local scale ecosystems are no longer under threat.’

To what extent do you agree with this view?

Which of the following are adaptations found in savanna vegetation?

A Buttress roots give the trees stability and access to nutrients found in the upper soil. Waxy leaves and drip tips help to remove large quantities of water during the short wet season.

B There are distinctive layers of vegetation adapted to deal with the intense summer insolation. Trees lose their leaves in winter as insolation levels fall and the dry season arrives.

C Only a few tree species can survive the long dry season. Waxy leaves reduce moisture loss. Deep tree roots reach groundwater. Grasses die and return during the wet season.

D Coniferous trees dominate and give way to small shrubs at the edges of the savanna. Needle-like leaves are adapted to cope with the large diurnal temperature variations.

What is a pioneer species?

A Following a drought, there is almost always significant die-back for most plant species. In these conditions, xerophytic pioneers colonise the area with limited competition.

B Pyrophytes are adapted to cope with conditions associated with wildfire. Root systems can cope with loss of vegetation above ground. This vegetation quickly returns after fire.

C Plant species which require very few nutrients to survive and will colonise bare rock. These species are the first to colonise following a volcanic eruption and succession follows.

D Once human activity has altered the climatic climax vegetation, the species are quick to adapt to the niche which is created. Pioneers readily exploit the available environment.

What is net primary productivity (NPP)?

A NPP is the biomass (minus respiration) produced in an ecosystem. It is a measure of the rate at which an ecosystem can capture and store carbon, usually measured in g/m²/yr.

B NPP relates to the productivity of land for the purposes of agriculture. The addition of nitrate-based fertilisers or genetically modified crops dramatically increases NPP.

C As plants respire they take in oxygen and release carbon dioxide. NPP is a measure of how much oxygen is produced by plants in an ecosystem. This rate is measured as O₂/m³/yr.

D NPP is the total amount of chemical energy (as biomass) that primary producers create in a given length of time. This is the rate at which decomposition occurs in an ecosystem.

Where are coral reefs typically found?

A Coral reefs form in latitudes between 30^o north and south of the equator. Sea temperatures ideally need to be around 26^oC. Coral reefs are unlikely to exceed depths of 50 metres.

B Coral reefs form wherever there is a sufficient food source and calm water. The upwelling of cold currents around 12^oC brings an ample supply of phytoplankton and zooplankton, a key food source.

C Algal blooms in the high latitudes at 60^o north provide the ideal circumstances for coral reef formation. Deep water coral is found off the east coast of Australia – the Great Barrier Reef.

D Coral is found anywhere on the planet. Provided the water is free from pollution and well sheltered from strong currents, some coral will form. It will not form in warm sea water.

Figure 11, on the insert, shows data related to Main Trophic Index (MTI) in selected sea areas around Europe between 1950 and 2004. MTI indicates the percentage change in top marine predators. Figure 12, on the insert, shows data related to the status of fish stocks in selected fishing regions around Europe in 2008.

Analyse the data shown in Figure 11 and Figure 12.

Analyse the human and ecological inter-relationships which lead to the development of a plagioclimax.

Assess the importance of global governance in securing the long-term health and survival of coral reefs.

‘It is simply not possible to find a true balance between biodiversity and sustainable economic development in savanna grasslands. Economic development will always come at the expense of biodiversity.’

To what extent do you agree with this view?