Temperature has a strong influence on species interactions and a lot of research has shown that it plays an important role in shaping biological communities. That’s why researchers were surprised to find that temperature did not affect the “competitive balance of power” between two rival species of Chilean barnacles.
Barnacles are a popular model for ecology research and happen to be particularly sensitive to temperature. For example, in the North Atlantic, the little gray barnacle (Chthamalus fragilis) can only survive high up on the rocks where it is hottest, but farther down, the northern rock barnacle (Semibalanus balanoides) takes over. Temperature is the main factor in the location of these barnacles.
That’s why researchers studying two barnacle species in Chile expected to see “clear effects on competition” between the two species if they altered the temperature. The results from this study would help researchers better understand how the coastline will be altered by climate change. But, the researchers found “no significant effect of temperature on competition at all.”
“Temperature wasn’t the beast that we often think of it being, which in itself is surprising,” co-author Heather Leslie of Brown University explained in a news release.
Like the barnacles in the North Atlantic, the Chilean barnacles, Jehlius cirratus and Notochthalamus scabrosus, also live in a stratified society; Jehlius is more abundant higher up and Notochthalamus is more abundant lower down, although they do blend somewhat in the highest rocks along the shore.
To see what effect temperature has on the growth, spatial cover, and reproductive output of the barnacles, researchers shaded ten 10 x 10 cm plots with plastic mesh and shade-cloth that acted as a roof. They monitored these sites along with ten other similar sites without shade regularly from February to August of 2010 and found that shade and cooler temperatures did not give either species an advantage over the other. In fact, both species grew better under the shade.
“Finding a pair of species that exhibit vertical zonation but do not strongly compete is unusual,” Lamb said.
The study will be printed in the 2014 issue of the Journal of Experimental Marine Biology and Ecology.
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