A student reads that the net primary productivity of a climax forest is low, and she concludes that…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
A student reads that the net primary productivity of a climax forest is low, and she concludes that a climax forest gives us less than a young forest does.
- Explain why the NPP of a climax community is low.
- Name two services that a climax forest gives better than a pioneer community.
- A farmer wants the highest yield of new plant matter for each year. Which stage of a succession would he prefer to keep, and why?
- Is the student's conclusion correct? Explain.
Need a reminder? The key ideaShow
and . Assimilation efficiency is assimilated divided by ingested. Net production efficiency is production divided by assimilated. Ecological efficiency is the production of a level divided by that of the level below.
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. (a) The climax community is large and has a very big biomass. It respires almost as much as it produces, so the P over R ratio is near . Little is left as net production.
Step 2. (b) Any two of: carbon storage (a large biomass), soil formation and protection, regulation of floods and water flow, habitat for many species, nutrient cycling.
Step 3. (c) A young or middle stage has a high NPP. A farmer keeps the community there, by ploughing or mowing, to get the greatest yield of new plant matter.
Step 4. (d) No. A low NPP does not mean a low value. The climax community stores a large biomass, holds the soil and the water, and shelters many species. These are services.
Answer: (a) respiration nearly equals production; (b) for example carbon storage and flood regulation; (c) a young or middle stage; (d) not correct, because the services are large.
Discussion (0)
Log in to join the discussion.
Loading…