Background
The authors write that "habitat reserves can promote ecological resilience to climate variability by supporting intact trophic webs and large-bodied individuals," citing Behrens and Lafferty (2004), Micheli et al. (2012) and Mumby et al. (2013). And they say that "protection may also alter community responses to long-term climate change by offering habitat for range-shifting species," noting the study of Thomas et al. (2012) in this regard.

What was done
As described by Bates et al., they analyzed "the species richness, diversity and functional traits of temperate reef fish communities over 20 years in a global warming hotspot [Maria Island Marine Reserve, Tasmania] and compared patterns in a marine reserve with nearby sites open to fishing."

What was learned
The six scientists found that "reserve sites were distinguished from fished sites by displaying: greater stability in some aspects of biodiversity; recovery of large-bodied temperate species; resistance to colonization by subtropical vagrants; and less pronounced increases in the community-averaged temperature affinity."

What it means
As a result of their arduous long-term study, Bates et al. were able, as they put it, to "empirically demonstrate that protection from fishing has buffered fluctuations in biodiversity and provided resistance to the initial stages of tropicalization," thereby demonstrating the significant virtues of protected fish communities and highlighting their inestimable ecological value.

References
Behrens, M.D. and Lafferty, K.D. 2004. Effects of marine reserves and urchin disease on southern California rocky reef communities. Marine Ecology Progress Series 279: 129-139.

Micheli, R., Saenz-Arroyo, A., Greenley, A., Vazquez, L., Montes, J.A.E., Rossetto, M. and De Leo, G.A. 2012. Evidence that marine reserves enhance resilience to climatic impacts. PLOS ONE 7: e40832.

Mumby, P.J., Wolff, N.H., Bozec, Y.-M., Chollett, I. and Halloran, P. 2013. Operationalizing the resilience of coral reefs in an era of climate change. Conservation Letters 7: 10.1111/conl.12047.

Thomas, C.D., Gillingham, P.K., Bradbury, R.B., Roy, D.B., Anderson, B.J., Baxter, J.M., Bourn, N.A.D., Crick, H.Q.P., Findon, R.A., Fox, R., Hodgson, J.A., Holt, A.R., Morecroft, M.D., O'Hanlon, N.J., Oliver, T.H., Pearce-Higgins, J.W., Procter, D.A., Thomas, J.A., Walker, K.J., Walmsley, C.A., Wilson, R.J. and Hill, J.K. 2012. Protected areas facilitate species' range expansions. Proceedings of the National Academy of Sciences USA 109: 14,063-14,068.