Maryland+Population+Review+Results

How many individuals can an area support?
===Before we talk about the number of populations that can survive over the long-term, we need to learn one more important concept that conservationists consider: key concept - carrying capacity.===


 * The analysts concluded that even under the best possible circumstances, none of the local populations in the collection of Maryland metapopulations have a significant chance of maintaining a minimum viable population by themselves. Populations in the Sassafras River metapopulation are especially vulnerable to local extinction (9).
 * =====The only way of preventing the eventual extinction of local populations along the Chesapeake Bay is to improve the habitat's degraded **carrying capacity** by allowing the cliffs to constantly erode. This would be accomplished by removing cliff vegetation, which drives the Puritan tiger beetle away (9, 24).=====
 * An experimental approach has been attempted at Sassafras River cliffs, in which herbicides were applied to remove fast growing vegetation that includes fast-growing exotic species. The results of this are still being analyzed (24). The Sassafras River populations remain precariously low (9).
 * Just as important as addressing habitat quality, **local populations need to be connected by having protected small areas between the local populations** that will allow individuals to migrate between them.
 * =====Without the presence of protected small passage areas, there will not be enough genetic flow to prevent the fragmented populations from going extinct.=====
 * =====As soon as a subpopulation goes extinct, it will probably trigger a domino effect of local extinctions that will eventually cause the extinction of the entire Calvert County population (9).=====
 * An obstacle to obtaining an adequate amount of permanently protected habitat is **a conflict over the space with humans**, who have recently purchased real estate over the cliff sites for the view of the Chesapeake Bay from their homes (2). The owners of these properties are attempting to arrest cliff erosion, which the beetles require, since it is destroying their investment. The conflicting interests of the property owners and the threatened Puritan tiger beetles is the center of an ongoing controversy that will be debated later in this unit. As the controversy simmers, the Calvert County metapopulation, the single largest population of Puritan tiger beetles, continues to decline (9).

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