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Applied Quiz: Invasive Species Removal

A second set of questions on this chapter, weighted toward using the ideas rather than recalling them. Each one puts you in a situation and asks what the chapter's framework says to do.

1. A volunteer group spends a Saturday cutting every buckthorn stem on a woodland lot. They do not treat the stumps. What does this chapter predict for next season?

  1. The buckthorn will be gone
  2. The site will be worse — each cut stump can send up five to ten new stems, so the stand comes back denser than before
  3. The buckthorn will return at roughly the same density
  4. Native plants will fill the gaps before buckthorn regrows
Show Answer

The correct answer is B. Bree calls this "the buckthorn trap," and the chapter names cutting without follow-up treatment as one of the most common and costly mistakes in invasive management. A day of hard work can leave the site harder to fix than before it started.

Concept Tested: Buckthorn Resprouting

See: Chapter 9

2. A contractor offers to clear your buckthorn "completely, in one season, guaranteed." Using this chapter, how should you read that?

  1. Accept — professional equipment can finish the job in one pass
  2. Treat it skeptically; buckthorn seeds stay viable in the soil for five years or more, so the chapter says anyone promising a one-season fix is mistaken or selling something
  3. Accept, but ask for a two-year warranty
  4. Refuse all professional help and do it by hand
Show Answer

The correct answer is B. The chapter states this almost word for word. The adult plants are the visible half of the problem; hundreds of seeds per square meter in the soil are the other half, and no single-season treatment reaches them.

Concept Tested: Buckthorn Seed Bank

See: Chapter 9

3. After clearing buckthorn, a landowner rototills the whole site to prepare for native seeding. What does this chapter say is wrong with that?

  1. Nothing — tilling is standard site preparation
  2. Disturbed soil exposes buried buckthorn seed to light and stimulates germination, so tilling can trigger a flush of exactly what was just removed
  3. Tilling kills native seed only
  4. Tilling is fine as long as herbicide was used first
Show Answer

The correct answer is B. "Minimize soil disturbance" is one of the chapter's seed-bank rules, sitting right alongside establishing dense native cover to compete with seedlings. Removal already increases light at ground level; adding soil disturbance compounds it.

Concept Tested: Managing the Seed Bank

See: Chapter 9

4. You pull garlic mustard in late May and pile the plants at the edge of the woods to compost. What has gone wrong?

  1. Nothing — pulled plants are dead
  2. Garlic mustard can keep ripening seed after it is pulled, so the pile becomes a seed source; the chapter says to bag pulled plants and remove them from the site
  3. May is too early to pull
  4. Composting is fine but the plants should be chopped first
Show Answer

The correct answer is B. This is a specific, easily-made error with a specific fix. The plant has enough stored resources to finish maturing seed pods after being uprooted, which is why "bag and remove" is a separate instruction from "pull."

Concept Tested: Garlic Mustard Removal

See: Chapter 9

5. A land manager has budget to work on either a high-quality remnant prairie with a small new knapweed patch, or a badly degraded lot completely overrun with it. What does the chapter's prioritization say?

  1. The degraded lot, because it has more invasive plants
  2. The remnant — protect your best remaining native areas first, and small early infestations are far cheaper to control than established ones; both criteria point the same way
  3. Split the budget evenly
  4. Neither; wait for more funding
Show Answer

The correct answer is B. Two of the chapter's four prioritization criteria — ecological value of the site and stage of invasion — line up here. Spending the same money on the overrun lot buys much less ecological return and probably does not finish the job.

Concept Tested: Prioritizing Removal Efforts

See: Chapter 9

6. You cut a large buckthorn stem at 9 a.m. and plan to come back with herbicide after lunch. What does this chapter say about that plan?

  1. Fine — timing within the same day makes no difference
  2. Treat the stump immediately; even a few hours of delay reduces effectiveness as the cut surface begins to seal
  3. Wait a full day so the stump dries
  4. Herbicide should be applied before cutting
Show Answer

The correct answer is B. The chapter's timing principles make this explicit. The open cut surface is the delivery route to the root system, and the plant starts closing it right away.

Concept Tested: Cut-Stump Treatment Timing

See: Chapter 9

7. Why does the chapter recommend late summer and fall for woody invasive removal rather than spring?

  1. The weather is more comfortable for volunteers
  2. In late summer and fall plants are moving carbohydrates down to their roots, so herbicide applied to a cut stump travels with that flow and reaches the root system
  3. Herbicide is cheaper in fall
  4. Woody plants are dormant and cannot resprout
Show Answer

The correct answer is B. The reasoning is about the direction of flow inside the plant. Treating with the downward carbohydrate movement carries the herbicide where it needs to go; treating against it in spring is far less effective.

Concept Tested: Seasonal Timing of Herbicide Treatment

See: Chapter 9

8. A group pulls garlic mustard from the same woodland every spring for four years, then skips year five because the population looks small. What does this chapter say happens?

  1. Nothing — four years is enough to exhaust the seed bank
  2. Skipping even a single year can undo several years of progress, because the surviving plants set seed and reload the seed bank
  3. The population will decline on its own by then
  4. Native plants will outcompete it after four years
Show Answer

The correct answer is B. The chapter reports this from land managers directly, and puts the required commitment at four to six years. A biennial that produces hundreds of seeds per plant only needs one unattended season to reset the clock.

Concept Tested: Persistence in Garlic Mustard Control

See: Chapter 9

9. After removing invasives from a woodland, what does this chapter say monitoring should watch for besides regrowth of the original species?

  1. Only regrowth matters
  2. New seedlings from the seed bank, different invasive species colonizing the disturbed area, and whether natives are actually returning or the ground is still bare
  3. Only whether natives return
  4. Soil pH changes
Show Answer

The correct answer is B. Removal creates a disturbed, well-lit opening, which is precisely the condition a different invader can exploit. The chapter's monitoring list covers all four items, and the site can fail in any of them.

Concept Tested: Follow-Up Monitoring

See: Chapter 9

10. A neighbor mows a patch of Wild Parsnip once in early August, after it has flowered. Evaluate that decision.

  1. Well timed — August mowing kills the plant outright
  2. Too late; the chapter's most important timing rule is to remove before seed set, and cutting a flowered plant in August risks having already added to the seed bank — the recommended approach is cutting the root below the crown in spring, wearing protection
  3. Correct, but he should have used herbicide
  4. Timing does not matter for biennials
Show Answer

The correct answer is B. "Remove before seed set" is the chapter's single most important timing rule, because a badly timed effort adds to the problem rather than reducing it. The species-specific guidance for wild parsnip is a spring root cut below the crown, with protective clothing against the sap.

Concept Tested: Removal Timing and Seed Set

See: Chapter 9