BIOL 1010 Chapter Notes - Chapter 7: Minimum Viable Population, Environmental Impact Statement, Ecosystem Management

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4 Nov 2016

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Bio 1010 - lecture 6 - chapter 7: population ecology. Core message: population size and makeup can fluctuate or remain stable. The stability of populations is often dependent on regulation by the environment or by other species like predators. If human impact has killed or removed predators, we may have to step in to fill their role. After reading this chapter, you should be able to know . What is carrying capacity and why do some populations slowly approach it and. Population- all the individuals of a species that live in the same geographic area and are able to interact and interbreed. Population dynamics- the changes over time of population size and composition. Minimum viable population- the smallest number of individuals that would still allow a population to be able to persist or grow, ensuring long-term survival. Environmental impact statement- an evaluation of the positive and negative impacts of a proposed environmental action, including alternative actions that could be pursued.

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Check the Course Announcements at the beginning of the week following the deadline for Part 1 to discover exactly what happened to the deer population on the Kaibab plateau. This information is essential for completion of Part 2.

The second part of your project is to take what you've learned about the Kaibab forest ecosystem and write an accurate description of the boom and bust of this deer population, using correct ecological language. Consider as many of the aspects of these events as you can. Be sure to consider the effects on the other species in the ecosystem as well.

Refer to your on-line materials and the appropriate sections of your textbook. Your discussion should include (but not be confined to) consideration of all of the following concepts: carrying capacity, predator/prey relationships, population cycling, resource partitioning, competitive exclusion, fundamental and realized niches, food chains, food webs and trophic pyramids.

Note that the purpose of this exercise is for you to demonstrate to me that you understand these important concepts of ecology by utilizing them accurately and appropriately in the description of the disaster in the Kaibab forest. Your essay must include both clear indications that you understand the meanings of these principles and clear indication that you understand how these principles can be used to describe what happened to the ecosystem on the Kaibab plateau.

information given of part one: On the north rim of the Grand Canyon, an area called the Kaibab plateau, there is a conifer forest called the Kaibab forest. The forest's trees include pine, fir and spruce. Shrubbery includes a variety of willows, raspberries, etc. A hundred years ago, this forest was a stable ecosystem, housing, among other species, a population of about four thousand mule deer.

These deer were hunted by local Native Americans, who used them for food and other materials. They were also hunted by predators like pumas, wolves and coyotes.

In 1906, the US made this region into a National Game Preserve. With the intent of protecting the deer, hunting was forbidden. Bounties were paid for killing the pumas, wolves and other large animals that preyed on the deer. By 1925, more than 6000 predators had been killed, virtually wiping out the ecosystem's large predators.

*Read the instructions* for Part 2, then consider this additional information about the Kaibab forest.
There are some hints in here to suggest the *minimum* range of the subjects you need to discuss to explain this; You will need to read the chapters and the course materials to understand the meanings of these concepts, and to be able to use them to explain the Kaibab disaster. There are other important concepts as well--so keep your eyes open as you read. It wouldn't hurt to go back and read the original description in Part 1, either. And you may find it necessary to do some quick browsing in areas of your book not directly related to ecology. (For instance, you might just want to do some looking into the nature and importance of the bark and twig ends on a tree.) Do not neglect the on-line essays which are provided for you in this Unit. What you should *not* do is Google the Kaibab, or look it up on a source like Wikipedia. This is not about what you can *discover* about the Kaibab forest.
Your grade will depend upon how completely you convince me you understand the concepts involved in this description. This is your test on ecology--your goal is to convince me that you understand the concepts and terminology of the subject, and can apply them to a real life situation.
Before we go on to the new information, there are a few things that came up as I was grading the Part 1 submissions which I think I should mention, just to keep you from straying in some incorrect directions.
First, remember that your concern is the fate of the Kaibab forest in the *immediate* sense--over tens of years, not thousands. There are no evolutionary issues here, at least in the short term (and that's your concern right now). So we won't be talking about adaptive radiation.
Also, keep your focus on the *Kaibab forest*, not on other ecosystems. Oh, and remember that the Kaibab is pretty isolated--emigration really isn't a reasonable alternative for the species living in this forest.
And finally, until we get to Part 3, the only human interaction we are considering is the initial decision to put bounties on those large predators, which led to their near-extinction in the area. You will be thinking a bit about human hunters trying to control the deer population toward the end, but the rest of the time you're just concerned with the natural processes going on in the ecosystem.
Okay, now on to the actual description of what happened in the Kaibab Forest as a result of killing almost all of the large predators. Remember, your task in Part 2 is going to be to describe and explain all of this using the concepts of ecology which you are learning in Unit 2 of the course.
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The primary, most immediate outcome of the removal of the predators from the ecosystem was that the deer population exploded, because the loss of the normal predator populations removed a primary source of population control. And the expanding deer population ate a *lot.* [Hint: explaining this requires discussion of population cycling, predator prey relationships and carrying capacities.]
As the deer population got larger and larger, their impact upon their favored food plants became extreme. They ate a much larger percentage of each year's plant populations, and they ate a larger portion of each individual plant. They also began to eat more from the plants which they didn't like so well--plants normally consumed by other herbivores in the ecosystem. In the winter, the starving deer ate about anything remotely resembling food, including twigs and bark from trees. As a result of the destruction of many of the twig ends of the trees, the spring tree growth was inhibited (why?). The stripping of the bark caused the death of some of the trees (why?). The extreme browsing on the herbaceous plants caused shifts in the plant population diversity, as the deer drove many of their favored plants into extinction within the ecosystem. [Hint: Explanation here will need to include discussion of resource partitioning, competitive exclusion, and realized vs. fundamental niches.]
All of this also impacted upon the rest of the animals in the ecosystem, since many of them depended upon the same kinds of food the deer ate, or depended upon the foods that the deer were eating because they could no longer get the food they favored. Then of course, the smaller predatory species (like foxes and owls) depended upon the health of those populations of small herbivores (like rabbits and mice). [Hint: sounds like food chains, food webs and trophic pyramids come into this part.]
After a couple of decades, the ecosystem was quite altered. The plant community was very different from what it had been before, and the deer herd, though not extinct, was composed of significantly smaller and weaker deer than the herd from the 1890s. (This was partially due to their straightened circumstances re. food, but also partially due to the absence of predators. Why would the removal of the natural predators cause this change in the general vigor of the deer in the herd (and why would the substitution of *human* hunting not exert the same positive influence)?)
Okay, the next phase of your assignment is to describe all the things going on in this ecosystem using the proper terminology that you should be learning from studying this unit of the course. Note that your use of terms like, for instance, "resource partitioning" needs to show that you understand not just what the concept means, but how it is reflected in this specific ecological disaster. Feel free to discuss this as much as you want to on your Discussion Board. Don't ignore the little questions tucked into the above description, and pay attention to those hints. Your response must demonstrate proper understanding of these concepts and how they are demonstrated by the disaster in the Kaibab forest.
This is the largest part of your exam project; your response should reflect the fact that this is a 50 point "essay" question. You are given a lot of organizational clues and hints about what issues you need to include in the information above. Make use of those things.

1.What is an ecological footprint? What is the greatestcontribution that you make to your footprint? How could you reduceit?

2. Are humans a keystone species? Support your answer.

3. Why does community connectedness matter?

4. Why does community change matter?

5. What kind of environmental features favor pioneer species,what kind favor climax/late succession species? What kinds ofadaptations favor pioneer species, and what kinds favor climaxspecies?

5. What do we mean when we say that landscapes are stable?

6. What would a community ecologist be able to learn from the USCensus?

7. What does evolution have to do with community ecology?

8. What role does disturbance play in ecology? Giveexamples.

9. You will be expected to be able to calculate species richnessand determine evenness and species diversity indices.

10. You will be expected to make a connection between carryingcapacity, population growth, and community succession in NewJersey.

11. What are the factors that can or could influence thecarrying capacity of NJ?

12. Rank the following three factors in terms of their impact onhuman carrying capacity: space availability, food availability,money availability.

13. Why are some invasive species more successful (i.e. havegreater fitness) in their introduced environment compared to theirnative environment?

14. What is global change about and how do our actions affectit? How is NJ going to be affected by global change?

15. Why, if it is summer in the southern hemisphere and winterin the northern hemisphere, do we see an overall increase in globalCO2 concentrations?

16. What is a dead zone and how is it created? What humanactivity (ies) help create a dead zone?

17. How would a fire that burns most of a forest affect theenergy, water, nutrient, and carbon cycles?

18. What are ecosystem services? Give an example of two.

19. Show how the energy and carbon cycles are inter-related.Explain what is happening in your diagram.

20. You need to be able to explain why nitrogen is important andwhy too much nitrogen is bad.

21. Which gas is more important for global warming:CO₂ or methane? Why?

22. What are the major carbon sinks and sources on earth?

23. What evidence do we have that CO2 concentration of theatmosphere has increased in the last 200 years and what evidence dowe have that that increase is due to human activity?

24. What is happening to our oceans in response to the increasein CO2 in the atmosphere. Be complete, there is more than one partto this answer.

25. How do we know that global warming is and will have animpact on populations, communities, and ecosystems?

26. Given what we know about Japanese knotweed, global change,and human activity, explain the interactions and consequences ofJapanese knotweed invasion on our water supply. You need toinclude, the physiology of the plant, the population ecology of theplant, the water cycle (ecosystems), and global change.

27. Regional climate change models predict that this area willget warmer and receive more rainfall. They also predict thatagriculture (i.e. growing plants) will suffer. Explain why. Becomplete in your answer. There are several factors at workhere.

28. Why are sea-levels increasing globally? Give a detailedanswer. What are some likely consequences going to be (other thanlosing land).

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BIOL 1010 Chapter Notes - Chapter 7: Minimum Viable Population, Environmental Impact Statement, Ecosystem Management

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