Range Shifts


When an animal or species finds a new suitable habitat or their current habitat becomes inhospitable they may undergo a range shift. A range shift is when an animal or species moves its range (the habitat that it uses) to a new area that it is better suited to. These range shifts occur more in species that are able to move or disperse easily. Range shifts have already been recorded in terrestrial animals in response to climate change. Terrestrial animals have been moving to higher elevations and higher latitudes, and animals moved the most in studies where there were the levels of warming were the highest. Another important aspect of range shifting is persistence. Persistence is a measure of how many generations a population can survive in an area. The persistence of west Indian manatees in new areas will determine whether or not their range can expand. 

This range increase estimation only accounts for new areas that west Indian manatees could live due to increase in water temperature, it does not take into account food, or any other factors.
As you may have read in the Meet the Manatee section, West Indian manatees are very sensitive to water temperature. You also might have seen that they are able and willing to adapt to new resources when available. This leads us to believe that when sea surface temperatures rise, manatees will be able to expand to the newly warmer places and exploit them. Sea surface temperature has already risen an average of 0.12 degrees Fahrenheit per decade during the past century. Above is a figure of my own creation showing the West Indian manatee’s current range, and projected range for 2100. Temperature is not the only factor that contributes to the possible range shift of the West Indian manatee, see the tab Seagrass and Range Shifts for more information. 


3 comments:

  1. UnknownNovember 8, 2012 at 5:35 PM

    This section seems to contradict itself. In one aspect, the manatees are seen as a species that can easily and readily expand to warmer climates and exploit the resources there. On the other hand, they are seen as very dependent on sea grass. Is that showing signs of migration as well? How much of the diet consists of seagrass? Try and figure out a conclusion on the net effect of temperature change, and clear this section up a bit.

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  2. AnonymousNovember 12, 2012 at 12:09 PM

    Is this your original figure? It clearly shows the future places that the manatees could live. It's a very easy to understand picture, but it does kind of contradict the text. It is explained in the caption, but maybe you could include a line or something showing where they would be if food is limiting. Perhaps you could talk about niches and fundamental versus realized niches and how although the range could expand, limiting factors might limit them. This might help clear up the confusion. You could also maybe include a figure like the one Dr. Harsch had in lecture of the niches.

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  3. Danielle AldenNovember 12, 2012 at 4:01 PM

    So if the manatees can adapt and experience range shifts, will they be affected by climate change negatively? This tab kind of makes it seem like the manatees will be fine, but then you talk about seagrass and how they depend on it. I think if you find a little more primary research on the topic and talk about what the ultimate predictions for manatee range shifts are, it would really help.

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