Chesapeake+Bay+Case+Study+responses

Question 1: Drawing from both this case study, and other portions of the unit that you have covered, what global, regional, and local threats to biodiversity are present in the Chesapeake Bay?

 * **Global warming** and an influx of **exotic species** are both **global** threats to biodiversity, present in the Chesapeake Bay.
 * Global warming is responsible for the rising water level that is submerging coastal habitat, and increasing the frequency and severity of coastal storms.
 * Exotic species in the Chesapeake Bay include both plant and animal species. As more exotic plant species appear in the bluffs in Puritan tiger beetle habitat in Calvert and Cecil county, erosion cycles are disrupted, which affects habitat suitability.
 * Various forms of pollution are a **regional** challenge to biodiversity in the bay.
 * **Local** threats to biodiversity include erosion control projects, and residential development.

Question 2: How might larger coastal storms, resulting from global warming create immediate threats of local extinction to a species like the Puritan tiger beetle?
A certain amount of disruption from coastal storms is expected, and beneficial to Puritan tiger beetles, although the storms may inflict significant population losses. The storms also clear accumulated vegetation in the cliffs and beaches, as well as sediments that have settled at the base of the cliff (colluvium). When these are removed by the erosive effects of coastal storms, the surviving population recovers due to improved hunting/foraging opportunities. The increased risk from local extinctions comes in conjunction with the long-term population decline, and the increase in strength of coastal storms associated with global climate change. Extirpations are more likely as a chance occurance if a declining population suffers a catastrophic loss from a large storm that reaches the Chesapeake Bay. This is an example of a phenomenon that has long been tolerated by Puritan tiger beetles, which is becoming more risky to them as population sizes approach dangerously small thresholds.

Question 3: If the Puritan tiger beetle was to disappear from the Chesapeake Bay, how do you think other species in this community would be affected?
There is no evidence that the species performs any critical ecosystem services. The Puritan tiger beetle is a voracious predator, and small insects such as ants and other beetles might be expected to increase in abundance in the absence of the loss of a predator. Tiger beetle larvae are preyed upon by parasitic wasps, which may find other hosts if the Puritan tiger beetle was unavailable.

Question 4: Is there anything that you can do to help preserve local biodiversity by responding to the global warming trend?
Yes. There are simple things that we can all do that reduce CO2 emissions, which in turn will reduce stress that climate change is putting on native species.


 * Use mass transit, carpool with friends, or ride a bike whenever possible.
 * When it’s time to replace the family vehicle, shop for one that gets more miles per gallon than your present vehicle.
 * If you have a small boat for fishing and recreation, run it with “human power” when possible.
 * Buy products that feature reusable, recyclable, or reduced packaging to save the energy required to manufacture new containers and reduce greenhouse gas emissions from landfills.
 * Plant trees, which remove carbon dioxide from the air.
 * Educate others. Let friends and family know about these practical, energy-saving steps they can take to save money while protecting the environment.

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