Question 1
Figure:Vegetation map of New Zealand
Key:
Figure:Topographic map of New Zealand
With reference to Figures: Topographic map of New Zealand and Vegetation map of New Zealand, identify a relationship between altitude and type of vegetation.
Figure:Vegetation map of New Zealand
Key:
Figure:Topographic map of New Zealand
With reference to Figures: Topographic map of New Zealand and Vegetation map of New Zealand, identify a relationship between altitude and type of vegetation.
a. Low/lower altitude is associated with bog/swamp/grass steppe/shrub steppe/subtropical laurel forest/subtropical rainforest/temperate broadleaf forest;
b. High/higher altitude is associated with alpine shrubland/highland steppe/temperate rainforest;
c. Mid/middle altitude is associated with temperate rainforest/temperate broadleaf forest;
d. Low/lower altitudes are associated with subtropical forests / mid/middle altitudes with temperate forests / high/higher altitudes are associated with grasslands;
e. The higher the altitude, the more grass steppe there is;
f. Zonation;
Note to examiners: accept any other reasonable responses. Do not accept just "steppe" or "rainforest", it must be specifically named for the appropriate altitude. Do not accept responses which simply state at which height range a specific vegetation type is located (e.g. Temperate broadleaf forest is located at 1000 m−1249 m ) as this is not a relationship.
Figure:Beaver-dam succession sequence — panel A
Figure:Beaver-dam succession sequence — panel B
Figure:Beaver-dam succession sequence — panel C
Figure:Beaver-dam succession sequence — panel D
Suggest how an ecologist might measure the changes in one abiotic factor along a transect from a beaver marsh, through beaver meadow to the adjoining forest.
use appropriate method/sampling device for identified abiotic factor eg use of thermometer to measure soil or air temperature / pH probe to measure pH value of soil / light sensor to measure light intensity / soil test kits to measure concentration of nutrients/nitrates/phosphates / hygrometer to measure humidity / use of soil moisture sensor/tensiometer / soil texture using different mesh size sieves;
use systematic sampling/interrupted belt transect/ take readings at regular intervals along transect;
repeat readings to obtain averages/increase reliability /take multiple readings to obtain average/increase reliability;
Figure:Stages of ecological succession after fire
Outline two reasons why the species within pioneer communities in the succession model shown above are more likely to be r-strategists than K-strategists.
r-strategists produce greater numbers/many offspring/fast population growth;
r-strategists distribute themselves more widely/colonize more quickly;
r-strategists mature quickly/reproduce earlier/establish themselves faster;
r-strategists better adapted to harsh/low-nutrient conditions/less specialised niches;
Do not accept just ANY valid characteristic of r-strategists (eg short life-span) ...only those directly relevant to a pioneer community as above.
Outline two reasons why the climax community in the succession model shown above is more stable than the intermediate community.
greater number of species/habitat/ecological niches/genetic diversity in climax community;
gross productivity/stored biomass is higher in climax community;
more complex/diverse energy pathways/food webs;
more established nutrient cycling;
more favourable abiotic conditions/soil properties;
more established negative feedback mechanisms;
Distinguish between zonation and succession.
succession is the process of changes in community/ecosystem over time, whereas zonation is the process of changes over an environmental gradient/space;
Outline two ways in which the food web is likely to change as a result of succession.
increasing numbers of trophic levels / longer food chains;
will be composed of new/different species;
more branching / greater complexity / more species at each trophic level;
greater gross productivity/energy transferred at each trophic level;
more biomass stored at each trophic level;
increased prominence of decomposer community;
Outline two ways in which the soil quality in the pioneer stages of the succession model shown above will differ from that in the climax ecosystem.
In pioneer communities... there will be lower organic content/leaf litter (due to combustion from the fire);
there may be a higher concentration of available minerals (released from ashes);
there may be fewer soil organisms (following deaths from fire);
it will be more prone to erosion/evaporation losses (through lack of vegetation cover/roots by fire);
less established nutrient recycling / reduced decomposer community;
Marking guidance:
Accept converse of these statements for climax community.
Note: The model shows SECONDARY succession (after fire), so not all generic features of a pioneer community in PRIMARY succession would be valid. eg in primary succession soil nutrients may be higher in climax community, but in secondary succession reverse is more likely (although processes of nutrient cycling/decomposition may still be more advanced established in climax community as in primary succession).